The Kynix Blog

SummaryAs we all known,better knowledge of the absorption and scattering of light inside the LED,the performance of white LEDs can be improved.Yeah,LEDs can be made even more efficient and powerful.When in May,2017,researchers who from the University of Twente and Philips Lighting have developed a new method which can lead to efficiency improvement and powerful design tools. They found a detailed way to describe the light that stays inside the LED by absorption and scattering. This is very valuable information for the design process. The Theory about Light Sources From relatively weak light sources to strong lights at home and in cars, for example: since the blue and white LED were invented, we've seen a rapid development in possible applications. Low energy consumption and long lifetime are major advantages over existing lighting solutions. White LEDs consist of a semiconductor emitting blue light, with on top of that phosphor plates that turn the blue light into yellow. What we see then, is white light. The light will be scattered by the phosphor particles, but it is absorbed as well. What part of the light will exit the LED, is not easy to predict. Unless you look at absorption and scattering in another way, according to Maryna Meretska and her colleages. Theory from astronomy helps. Good Prediction is Difficult What makes good prediction particularly difficult: some of the light is absorbed, but re-emitted in another colour. One way is trying to define all possible light rays, and use a lot of computing time to get a result. This doesn't give much insight in what is actually happening. A theory that is often used for light propagation in a LED, is diffusion theory. In strongly absorbing media, however, this approach isn't valid anymore. Meretska therefore has built a setup to collect all the light around the phosphor plates, in the whole visual spectrum. Based on this, absorption and scattering can be deduced using the radiative transfer equation, well known in astronomy.  This results in a full description of light propagation inside and outside the phosphor plates. Compared to a description using diffusion theory, the absorption level is up to 30 percent higher. At the same time, the method is about 17 times faster than the numerical approach. ConclusionThis new insights leaded to powerful and predictive tools for LED designers.They help in further improving the efficiency and overall performance.The research has been done in the Complex Photonic System group of UT's MESA+Institute for Nanotechnology,together with Philips Lighting in Eindhoven. The University of Twente has a strong concentration of research groups and facilities within the rapidly growing field of photonics.  Article provided by University of TwenteArticle edited by kynix 

 This article is a brief introduction to contactor.  Catalog  I. What is a Contactor?II. Differences Between Contactor and RelaysIII. Contactor Working PrincipleIV. About Arc SuppressionFAQ I. What is a Contactor? As an essential part of the motor control gear, the most widespread switching device used in a starter is the a,c. airbrake contactor which consists of contact assemblies actuated by electromagnetic action. An operating coil is enclosed by the magnetic yoke, as well as when energized attracts an armature to which is attached a set of moving contacts which make with a set of stationary contacts. Modern contractors use a silver alloy contact tip, normally silver–cadmium oxide or silver–tin oxide alloy attached to a brass or copper backing strip. The choice of tip material is critical and is normally established after many types of tests.  Note: The rating of the contactor depends on the size, shape, and material of the contacts and on the efficiency of the arc extinction method used. An electrical contactor is an electromagnetic switch similar to a relay. It is a switch that can be controlled with the current/pulse to switch over an electrically powered circuit. II. Differences Between Contactor and Relays Let me put forward a basic question firstly:If you see in industrial control panels, both relays and contractors are used for the same purpose, so why different names? Both of them perform the same task. The relay is usually used in low voltage paths such as switching tube-light or small LEDs. The contactor is used in electrical circuits of industrial motors or other heavy applications. So, the difference is from an application point of view. The basic working principle is the same for both. The relay behaves similarly to how a contractor works. If you want to switch circuits with high voltages, use contactors and if you want to switch light voltages then the relay is ready for you.  It is important to note here the difference between protection and switching. A relay is a protection device whereas a contactor cannot assure you about protection. The relay can differentiate between normal & abnormal conditions and give command accordingly which contactor cannot. Switching means to break and make a circuit and a contactor is mainly used for that purpose. III. Contactor Working Principle When the contactor coil is de-energized, gravity or a spring returns the electromagnet core to its initial position and opens the contacts. For contactors energized with alternating current, a small part of the core is surrounded by a shading coil, which slightly delays the magnetic flux in the core. The following video will help you understand the working principle of contactor more intuitively:  IV. About Arc Suppression Most motor control contactors at low voltages (600 volts and less) are air brake contactors; air at atmospheric pressure surrounds the contacts and extinguishes the arc when interrupting the circuit. Modern medium-voltage AC motor controllers use vacuum contactors. High voltage AC contactors (greater than 1,000 volts) may use a vacuum or an inert gas around the contacts. High voltage DC contactors (greater than 600V) still rely on air within specially designed arc-chutes to break the arc energy. High-voltage electric locomotives may be isolated from their overhead supply by roof-mounted circuit breakers actuated by compressed air; the same air supply may be used to "blow out" any arc that forms.Without adequate contact protection, the occurrence of electric current arcing causes significant degradation of the contacts, which suffer significant damage. An electrical arc occurs between the two contact points (electrodes) when they transition from a closed to an open (break arc) or from an open to a closed (make arc). The break arc is typically more energetic and thus more destructive. Without adequate contact protection, the occurrence of electric current arcing causes significant degradation of the contacts, which suffer significant damage. An electrical arc occurs between the two contact points (electrodes) when they transition from a closed to an open (break arc) or from an open to a closed (make arc). The break arc is typically more energetic and thus more destructive.FAQ 1. What is the main function of contactor?Function of contactor, generally used for connected and disconnected of electric current supply. Usually in use for applications: motors, heater, lighting or electric power distribution. 2. Why do we need contactors?Contactors are used for high power applications. They allow a lower voltage and current to switch a much higher power circuit, so they are generally larger and more heavy-duty than control relays, enabling them to switch higher power loads on and off for many thousands of cycles. 3. How a contactor is wired?Break your circuit, L N E through your contactor. Link a permanent live and a neutral from your supply to your coil (Al + A2) then use your switch feed to your photocell from A1, and switch the wire to the switched phase of your contactor load. This should now open when light, close when dark. 4. What is NO and NC In Contactor?Normally Open (NO) and Normally Closed (NC) terms refer to type of dry contact or wet contact. Put very simply, a Normally Open sensor will have no current when in a normal state but when it enters an alarm state it will have +5V applied to the circuit. 5. How many types of contactors are there?The contacts are classified as power contact, auxiliary contact, and contact spring. There are two types of power contact; stationary contact and movable contact. The material used for the contacts has stable arc resistance and high welding resistance. 6. Why contactor is used?Contactors are used for high power applications. They allow a lower voltage and current to switch a much higher power circuit, so they are generally larger and more heavy-duty than control relays, enabling them to switch higher power loads on and off for many thousands of cycles 7. What is the difference between a relay and a contactor?A contactor joins 2 poles together, without a common circuit between them, while a relay has a common contact that connects to a neutral position. Additionally, contactors are commonly rated for up to 1000V, while relays are usually rated to only 250V. 8. What are the types of contactors?There are different types of contacts in a contactor, and they are; auxiliary contact, power contact, and contact spring. The power contact has two types that are; stationary and movable contact. Material for making contacts must have a high welding resistance and stable arc resistance. 9. What are the three major parts of a contactor or relay?There are three major parts of a contactor or relay: the coil, mechanical linkage and contacts. The coil is used to create a magnetic field and is rated based on voltage (24 V, 120 V, 208/204 V, 480 V). The mechanical linkage connects the armature to the contacts when the coil is energized, completing the circuit. 10. How contactor is connected?A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagnet controlling a 230-volt motor switch. Unlike general-purpose relays, contactors are designed to be directly connected to high-current load devices. 

This blog is about GPS and inertial sensors for driverless cars. GPS is an essential technology for today's driving locations. However, due to the error, multi-path, and low update frequency of GPS, we cannot rely on it for positioning. Inertial sensors have a high update frequency and can be used in conjunction with GPS. CatalogI Self-driving car positioning technologyII Introduction to GPSIII Introduction to inertial sensorsIV GPS and inertial sensor fusionV GPS vs inertial sensor & GPS vs   inertial sensor fusionVI ConclusionFAQI Self-driving car positioning technologyDriving location is one of the core technologies of Driverless cars. Global positioning system (GPS) also plays a very important role in driverless positioning. However, unmanned vehicles are driving in complex dynamic environments, especially in metropolitan areas, where GPS multipath reflections can be significant. This GPS positioning information is very easy to produce an error. Such errors are likely to cause traffic accidents for cars traveling at high speed over limited widths. Therefore, we must rely on other sensors to assist positioning and enhance the positioning accuracy. In addition, due to the low frequency of GPS update (10Hz), it is difficult to provide accurate real-time positioning when the vehicle is driving fast.The inertial sensor (IMU) is a high-frequency (1KHz) sensor that detects acceleration and rotational motion. After the inertial sensor data is processed, we can get the displacement and rotation information of the vehicle in time. However, the inertial sensor itself also has the effect of deviation and noise . By using Kalman filter-based sensor’s fusion technology, we can integrate GPS and inertial sensor data to achieve better positioning results. Because unmanned driving’s requirements for reliability and safety are very high, positioning based on GPS and inertial sensors is not the only way to locate. We also match LiDAR with high-precision map, or position by visual odometer, so that a variety of positioning method will be adopted to correct each other in order to achieve more accurate results.II Introduction to GPS Global Positioning System (GPS) is an indispensable technology for current driving location and plays a very important role in driverless positioning. The GPS system includes 32 GPS satellites in space, 1 master control station on the ground, 3 data injection stations and 5 monitoring stations, and a GPS receiver as a subscriber station. With at least three of these satellites, the location and altitude of the client on Earth can be quickly determined. Now civilian GPS can reach about 10 meters positioning accuracy. The GPS system uses low-frequency signals and maintains considerable signal penetration, even in poor weather. Following i will analysis GPS operating principle and technical flaws.Figure 1. GPS three-way measurement of positioning2.1 Trilateration methodAs shown in Figure 1, GPS positioning system is the use of satellite basic triangulation Principle, utilizing GPS receiver to measure the transmission time of radio signals to measure the distance. From the location of each satellite, the distance between each satellite and the receiver can be measured to calculate the coordinates of the three-dimensional space of the receiver. Users receive the device as long as the use of three satellite signals received, you can set the user's location. In practice, GPS receiving devices use more than four satellite signals to locate the location and height of the user. Triangle positioning works as follows:Assuming that we measure the distance of the first satellite to 18,000 km, we can limit the current range of possible locations to 18,000 km above the surface of the Earth from the first satellite.Next, suppose we measure a distance of 20,000 km from the second satellite, and then we can further limit the current location to an intersection of 18,000 km from the first satellite and 20,000 km from the second satellite.Then we will measure the third satellite again and locate the current position through the intersection of the three satellites. Normally, the GPS receiver uses the location of the fourth satellite to confirm the position measurements of the first three satellites for better results.2.2 Distance measurement and precise time stampingIn theory, distance measurement is a simple process, and we only need to multiply the signal propagation time by the speed of light to get the distance information. But the problem is that the measured propagation time, any error, will result in a huge distance error. There is a certain amount of error in the clock we use every day. If we use quartz clock to measure the propagation time, there is a big error in GPS-based positioning. To solve this problem, atomic satellites are installed on each satellite to achieve nanosecond-level accuracy. In order for the satellite positioning system to use a synchronous clock, we need to have atomic clocks installed on all receivers as well. But atomic clocks cost tens of thousands of dollars, making it impractical for every GPS receiver to install such an expensive thing. In order to solve this problem, atomic clocks can still be used on every satellite, but ordinary quartz clocks often need to be calibrated at the receiver. Receivers receive signals from four or more satellites and calculate their own errors to adjust their own clock to a uniform time value.2.3 Differential GPSAs mentioned above, there are problems such as errors caused by satellite clocks and delays in satellites' distance measurement. Using differential technology, we can eliminate or reduce these errors, so GPS to achieve higher accuracy. The principle of differential GPS operation is quite simple: if both GPS receivers are fairly close to each other, the signals from both will have almost the same error. If the error of the first receiver can be accurately calculated, The results of the two receivers are corrected.Figure 2. Differential GPSHow to accurately calculate the error of the first receiver? We can place the reference receiver reference station at a known and accurate location. As shown in Figure 2, the GPS receiver installed on the reference station can observe three satellites and perform three-dimensional positioning to calculate the measurement coordinate of the base station. Then we can calculate the error by comparing the measured coordinates with the known coordinates. The reference station then sends the error value to a differential GPS receiver within a radius of 100 km to correct their measurement data.Figure 3. Multipath problem2.4 Multi-path problemAs shown in Figure 3, the multipath problem refers to the error of the signal propagation time caused by the reflection and refraction of GPS signals, which leads to positioning errors. Especially in urban environments, there are many suspended media in the air that reflect and refract GPS signals, and signals that reflect and refract on the outer walls of tall buildings, all of which cause confusion in distance measurements. The current high-precision military differential GPS, in the static and "ideal" environment can indeed achieve centimeter-level accuracy. The "ideal" environment here means that there is not too much suspended medium in the atmosphere, and the GPS has a stronger received signal when measured. However, unmanned vehicles are driving in a complex and dynamic environment, especially in large cities, GPS multipath reflections will be more obvious. This GPS positioning information is very easy to have a few meters of error, is likely to lead to traffic accidents.Even with all sorts of problems, GPS is still a relatively accurate sensor, and GPS errors do not increase over time. However, one problem with GPS is the low update frequency, which is around 10Hz. Due to the speed of unmanned vehicles, we need real-time precise positioning to ensure the safety of unmanned vehicles. Therefore, we must rely on other sensors to assist positioning and enhance the positioning accuracy.III Introduction to inertial sensorsThe inertial sensor (IMU) is a sensor that detects acceleration and rotational movement. The basic inertial sensors include accelerometers and MEMS gyroscope. This article focuses on MEMS-based six-axis inertial sensors, mainly by the three-axis acceleration sensor and three-axis gyroscope components.Here is a video introducing Inertial Sensor in detail：Inertial sensor introductionMEMS inertial sensors are divided into three levels: Low-precision inertial sensors are mainly used in consumer electronics products, smart phones, such sensors priced at 50 cents to a few dollars, but the measurement error will be relatively large. Intermediate inertial sensors are mainly used in automotive electronic stability systems and GPS-assisted navigation systems, such sensors priced at hundreds to thousands of dollars, relative to the low-end inertial sensors, intermediate inertial sensors in the control chip measurement error correction, So the measurement result is more accurate. However, after a long period of operation, the cumulative error will increase. High-precision inertial sensors as a military-grade and space-grade products, requiring high-precision, temperature zone, shock and other indicators. Mainly used for communications satellite wireless, missile seeker, optical aiming system and other stable applications. Such sensors are priced in the hundreds of thousands of US dollars range, even after a long run, such as transcontinental intercontinental missiles, still can achieve the rice level accuracy.Unmanned aerial vehicles are generally low-level inertial sensors. It is characterized by high update frequency (1KHz), can provide real-time location information. But the fatal disadvantage of an inertial sensor is that its error increases over time, so we can only rely on inertial sensors for positioning in a short period of time.Figure 4. Accelerometer3.1 AccelerometerFigure 4 shows the MEMS accelerometer, which works by virtue of the inertia of the moveable part of the MEMS. Because of the large mass of the intermediate capacitor plate and its cantilever configuration, the inertial force it receives exceeds the force that holds or supports it when the speed or acceleration is large enough, at which point it moves, keeping it up and down The distance between the plates will change, the upper and lower capacitors will change accordingly. Capacitance changes with the acceleration is proportional to. Depending on the measurement range, the strength or spring constant of the cantilever structure of the intermediate capacitor plate can be designed differently. And if you want to measure the acceleration in different directions, the structure of this MEMS will be very different. Capacitor changes will be another piece of dedicated chip into a voltage signal, and sometimes the voltage signal will be amplified. The voltage signal is digitized and processed through a digital signal that is output after zero and sensitivity correction.Figure 5. MEMS gyroscope3.2 MEMS gyroscopeFigure 5 shows the MEMS gyroscope, which works on the principle of conservation of angular momentum. It is a non-rotating object whose axis of rotation does not change with the rotation of the support carrying it. Similar to the working principle of an accelerometer, the upper active metal of the gyroscope forms a capacitance with the underlying metal. As the gyroscope rotates, the distance between the gyro and the underlying capacitive plate changes, and the upper and lower capacitances change accordingly. The change in capacitance is proportional to the angular velocity, so we can measure the current angular velocity.3.3 Inertial sensor problemDue to the production process, inertial sensor measurements usually have some error. The first error is the offset error, ie, the gyroscope and accelerometer will have non-zero data output even without rotation or acceleration. To get the displacement data, we need to integrate the accelerometer's output twice. After two integrations, even a small offset error will be magnified and as time progresses, the displacement error will accumulate, ultimately resulting in no further tracking of the UAV's position. The second error is the ratio error, the ratio between the measured output and the change in the sensed input. Similar to the offset error, after two integrals, the error caused by the displacement will accumulate over time. The third kind of error is the background white noise that, if not corrected, can also prevent us from tracking the location of the UAV.In order to correct these errors, we must calibrate the inertial sensor, find the offset error, the proportional error, and then use the calibration parameters to correct the original data of the inertial sensor. But the complication is that the error of the inertial sensor will also change with the temperature. Even if we make the best adjustments, as time goes on, the displacement error will continue to accumulate, so it is very difficult for us to use inertial sensors to locate UAV alone.IV GPS and inertial sensor fusionAs mentioned above, GPS is a relatively accurate positioning sensor even with multi-path problems. However, the update frequency is low and can not meet the requirements of real-time calculation. The inertial sensor positioning error will increase with the running time, but because it is a high-frequency sensor, in a short period of time can provide stable real-time location updates. Therefore, as long as we find a way to combine the advantages of these two sensors, each director, you can get more real-time and accurate positioning. Below we discuss how to use the Kalman filter to fuse the two sensor data.4.1 Introduction to Kalman FilterKalman filter predicts the position coordinates and velocity of an object from a set of observations that contain a limited set of noise-containing object positions. It has strong robustness. Even if there is an error in the observation of the object's position, we can accurately estimate the position of the object based on the historical state of the object and the current observation of the position. The Kalman filter is mainly divided into two phases: the prediction phase predicts the current position based on the position information of the previous time point; the update phase updates the position of the object by correcting the position prediction by observing the current position of the object.To give a concrete example, suppose you have a power outage without any light and you want to walk back to the bedroom from the living room. You know the relative position of the living room to the bedroom, so you walk in the dark and try to predict the current position by counting steps. Halfway through, you touch the TV. Since you know in advance the approximate location of the television in the living room, you can correct your prediction of the current location by the location of your television set, and then continue to rely on the calculated steps based on the more accurate adjusted position estimate Several to the bedroom forward. Relying on the calculation of the number of steps and touch the object, you eventually dark from the living room back to the bedroom, the truth behind this is the core principle of Kalman filter.Figure 6. GPS and IMU sensor fusion positioning4.2 Multi-sensor fusionAs shown in Figure 6, the fusion of inertial sensors and GPS data using a Kalman filter is very similar to the example given above. Inertial sensor here is equivalent to a few steps, and GPS data equivalent to the location of the reference TV. First of all, based on the last position estimation, we use the inertial sensor to predict the current position in real time. Before getting new GPS data, we can only predict the current position by integrating the data of inertial sensors. However, the positioning error of inertial sensors increases with runtime, so we can use this GPS data to update the current position prediction as new, more accurate GPS data is received. By constantly implementing these two steps, we can take the director of both to accurately locate the unmanned vehicle in real time. Assuming that the frequency of the inertial sensor is 1 KHz and the frequency of the GPS is 10 Hz, we can use 100 inertial sensor data points for position prediction between every two GPS updates.V GPS vs inertial sensor & GPS vs inertial sensor fusionThis article describes the principle of using GPS and inertial sensors to accurately position a vehicle in an unmanned location. The system consists of three parts, a relatively accurate but low-frequency update GPS, a high-frequency update but increasingly unstable precision inertial sensors over time, and a Kalman filter-based mathematical model to fuse both Sensors, take the director, in order to achieve fast and accurate positioning effect. However, since driverless reliability and safety requirements are very high, in addition to GPS and inertial sensors, we often use positioning methods such as LiDAR and high-precision map matching, visual odometer and the like to make various positioning France correct each other in order to achieve more accurate results.VI ConclusionThis article focuses on GPS and inertial sensors for driverless applications. GPS is an indispensable technology for current driving location.But due to GPS error, multipathing and low update frequency, we can not rely on GPS for positioning. The inertial sensor has a high update frequency that can complement with GPS. Using sensor fusion technology, we can integrate GPS and inertial sensor data in order to achieve better positioning results.FAQ 1. What is GPS and its uses?The Global Positioning System (GPS) has been developed in order to allow accurate determination of geographical locations by military and civil users. It is based on the use of satellites in Earth orbit that transmit information which allow to measure the distance between the satellites and the user. 2. What GPS means?Global Positioning System. The Global Positioning System (GPS) is a U.S.-owned utility that provides users with positioning, navigation, and timing (PNT) services. 3. How does the GPS work?GPS is a system of 30+ navigation satellites circling Earth. We know where they are because they constantly send out signals. A GPS receiver in your phone listens for these signals. Once the receiver calculates its distance from four or more GPS satellites, it can figure out where you are. 4.What is importance of GPS?Why GPS is Important? GPS includes space-base satellites, computers and receivers which provide your location information in every weather conditions anywhere at any time in the world. It was originally made for the US military to locate their troops in deserted areas and forests. 5. How is GPS useful in our daily life?Using GPS tracking systems, you can manage employee transportation fleet and improve its efficiency. You can save time and fuel, thereby minimizing expenses. While travelling, the feature in the GPS could track the luggage, laptop, and important personal belongings. 6. What is an IMU sensor?An IMU is a specific type of sensor that measures angular rate, force and sometimes magnetic field. ... Technically, the term “IMU” refers to just the sensor, but IMUs are often paired with sensor fusion software which combines data from multiple sensors to provide measures of orientation and heading. 7. How does an inertial device work?How Does an IMU Work? IMUs can measure a variety of factors, including speed, direction, acceleration, specific force, angular rate, and (in the presence of a magnetometer), magnetic fields surrounding the device. IMUs combine input from several different sensor types in order to accurately output movement. 8. How do you use the IMU sensor?An IMU sensor unit working can be done by noticing linear acceleration with the help of one or additional accelerometers & rotational rate can be detected by using one or additional gyroscopes. Some also contain a magnetometer which can be used as a heading reference. 9. Why magnetometer is used in IMU?The third component of our IMU is the magnetometer. This is where I have seen people facing difficulties. It is a device capable of measuring magnetism. It is able to help us find orientation using the earth's magnetic field, similar to a compass. 10. How do I choose an IMU sensor?Some of the aspects we have to consider when we have to select an IMU are performance, underlying technology, SWaP (Size, Weight, and Power) and Cost. Besides, another important factor in UAVs is the ruggedness of the IMU. In harsh UAV applications, vibrations can reach a high level and different temperatures. 

Image Source: unsplashWhen your device needs a CR1616 battery, finding the right replacement can feel tricky. Luckily, there are reliable alternatives like CR1620, CR2016, and BR1616. Each of these coin cell battery options offers unique benefits, but you’ll want to pick one that matches your device’s requirements.Choosing the wrong alternative could lead to performance issues or even damage your device. Always check the size, voltage, and manufacturer recommendations before making a decision. Your device deserves the best fit, so don’t compromise on safety or compatibility.What Is a CR1616 Battery?The CR1616 battery is a small but powerful coin cell battery that’s commonly used in various small electronic devices. Its compact size and reliable performance make it a go-to choice for gadgets that require low energy but consistent power. If you’ve ever wondered what makes this battery tick, let’s dive into its features and specifications.Specifications of the CR1616When it comes to the CR1616, its technical details are what set it apart. Here’s a quick look at its key specifications:SpecificationValueVoltage3VDiameter16 mmThickness1.6 mmCapacity50 mAhChemistryLithium Manganese DioxideApplicationsWatches, Calculators, Medical DevicesYou’ll notice that its small size (16 mm in diameter and 1.6 mm thick) makes it ideal for compact devices. It also weighs just about 1.2 grams, so it won’t add unnecessary bulk to your gadgets. With a voltage of 3V and a capacity of 50 mAh, this battery delivers steady power for extended periods.Common Uses of the CR1616You might be surprised by how many everyday items rely on the CR1616 battery. Here are some of its most common applications:Remote Controls – Its compact size and sufficient power make it perfect for remote controls.Calculators – Many scientific and basic calculators use this battery to keep running smoothly.Digital Watches – The CR1616 powers digital watches, ensuring accurate timekeeping and additional features.Key Fobs – Car key fobs often depend on this battery for remote entry systems.These small electronic devices benefit from the CR1616’s reliable performance and long-lasting power. Whether it’s your watch or your car key fob, this battery ensures your gadgets work when you need them most.Compatible Alternatives to the CR1616When your CR1616 battery runs out, you might wonder if there’s a suitable replacement. Luckily, there are several close alternatives that can work just as well. Let’s explore some of the most popular options and see how they compare.CR1620: A Slightly Thicker OptionThe CR1620 battery is one of the closest alternatives to the CR1616. It shares the same 3V voltage and lithium chemistry, making it a reliable choice for many devices. However, the key difference lies in its thickness. While the CR1616 is 1.6 mm thick, the CR1620 measures 2.0 mm. This slight increase in thickness means it may not fit in devices with very tight battery compartments.Here’s a quick comparison of the two:Battery TypeThickness (mm)Capacity ComparisonCR16161.6LowerCR16202.0HigherThe CR1620 battery also offers a higher capacity, which means it can last longer in devices that can accommodate its size. If your device has a bit of wiggle room in the battery slot, the CR1620 could be a great option. Just double-check the fit before making the switch.CR2016: A Larger Diameter AlternativeIf you’re looking for another battery equivalent, the CR2016 might catch your eye. This option has the same thickness as the CR1616 (1.6 mm), but its diameter is larger at 20 mm compared to the CR1616’s 16 mm. This makes it unsuitable for devices with small, circular battery compartments.Here’s how the two stack up:Battery TypeDiameter (mm)Thickness (mm)CR1616161.6CR2016201.6The CR2016’s larger size also means it has a higher capacity, so it can power devices for longer periods. However, it’s only a viable option if your device can accommodate the extra diameter. Always check your device’s specifications before opting for this alternative.Other Equivalent Batteries (BR1616, DL1616, ECR1616, GPCR1616)In addition to the CR1620 and CR2016, there are other equivalent options that might work for your device. These include the BR1616, DL1616, ECR1616, and GPCR1616. All of these batteries share the same size and voltage as the CR1616, making them direct replacements.BR1616: This is a lithium-based battery with a focus on long-term stability. It’s ideal for devices that require consistent performance over time.DL1616: Manufactured by Duracell, this battery is known for its reliability and wide availability.ECR1616: Energizer produces this equivalent, offering a trusted name in battery technology.GPCR1616: This option comes from GP Batteries, a brand known for its affordability and quality.These alternatives are perfect if you’re looking for a direct replacement without worrying about size or compatibility issues. Just make sure to choose a reputable brand to ensure safety and performance.Tip: Always check your device’s manual or battery compartment for specific recommendations. This will help you pick the most compatible option.Comparing CR1616 AlternativesImage Source: unsplashSize and DimensionsWhen choosing a replacement for your CR1616 battery, size matters. Even a slight difference in dimensions can affect whether the battery fits snugly in your device. Let’s break it down with a quick comparison of the CR1616 and its alternatives:SpecificationCR1616CR1620CR2025Diameter (mm)161620Height (mm)1.62.02.5Mass (g)1.22.62.6As you can see, the CR1620 shares the same diameter as the CR1616 but is slightly thicker. This makes it a good option if your device has a bit of extra room in the battery compartment. On the other hand, the CR2025 is both wider and thicker, which means it’s only suitable for devices designed to accommodate larger batteries. Always check your device’s manual to ensure the replacement fits properly.Voltage and CapacityVoltage and capacity are critical when selecting a replacement. The CR1616 battery operates at 3 volts, which is standard for most coin cell batteries. Its capacity, however, is 50 mAh, which determines how long it can power your device. Here’s how it compares to its alternatives:CR1620: Offers the same 3V voltage but has a higher capacity of around 70 mAh. This means it can last longer, provided your device can handle the extra thickness.CR2025: Also operates at 3V but boasts an even higher capacity of 150 mAh. While this might seem appealing, its larger size limits its compatibility with smaller devices.If you’re looking for a voltage and capacity match, the CR1620 is often the closest alternative. However, always prioritize compatibility over capacity to avoid damaging your device.Performance and LongevityBattery performance depends on both capacity and the type of device you’re using. The CR1616 is designed for low-drain devices like watches and key fobs, where it can last for months or even years. Alternatives like the CR1620 and CR2025 offer longer lifespans due to their higher capacities, but only if your device can accommodate them.For example, a CR1620 might last longer in a digital watch compared to a CR1616, thanks to its increased capacity. However, using a battery that doesn’t fit properly can lead to poor connections and reduced performance. Always test the alternative in your device to ensure it delivers consistent power.Tip: Stick to trusted brands when purchasing replacements. A high-quality battery ensures better performance and longevity, keeping your device running smoothly.Factors to Consider When Choosing an AlternativeWhen replacing your CR1616 battery, you can’t just grab the first alternative you see. There are a few important factors to keep in mind to ensure your device works properly and stays safe. Let’s break it down step by step.Device CompatibilityThe first thing you need to check is whether the alternative battery will fit and function in your device. Even small differences in size or voltage can cause issues. For example, the CR1620 is slightly thicker than the CR1616, which might make it unsuitable for devices with tight compartments. On the other hand, a larger button like the CR2016 won’t fit in smaller slots due to its wider diameter.To ensure compatibility, manufacturers and testing organizations have developed standardized methods to validate battery performance. Here’s a quick look at some of these tests:Testing MethodDescriptionApplicationExtremely Lean Electrolytic Testing (ELET)Developed based on electrolyte depletion behavior during cell cycling.Validates performance across different cell configurations, including Li-S and Li-NCA systems.Additionally, these certifications can help you identify reliable alternatives:CTIA Battery Certification ProgramIEEE Standard 1725TM1-2006UL 1642 Lithium CellUL 2054 Nickel Cell or Lithium/Nickel PacksIEC 60086-1 and IEC 60086-2 Non-rechargeable PerformanceIEC 61960 Performance of Rechargeable LithiumAlways check your device’s manual for specific recommendations. If it lists the CR1616, look for alternatives with similar features, like the CR1620 or BR1616. This ensures your device gets the power it needs without any hiccups.Safety PrecautionsSafety should always come first when choosing a battery alternative. Using the wrong type can lead to overheating, leakage, or even damage to your device. Non-rechargeable batteries like the CR1616 and CR1620 are designed for specific uses, so trying to recharge them or use them in high-drain devices can be dangerous.Statistical data highlights the importance of safety precautions. For instance:Electric vehicles have a 1 in 38,000 chance of catching fire, compared to 1 in 1,300 for gasoline vehicles.The failure rate of electric vehicles is around 0.9 to 1.2 per 10,000, much lower than fossil fuel-burning vehicles.While these stats focus on larger batteries, they emphasize the importance of using the right battery for the job. Always handle button batteries carefully, especially around children. These small batteries, like the CR1616 or l1154 battery, can pose a choking hazard if swallowed. Store them in a safe place and dispose of used batteries properly.Tip: Look for batteries with child-resistant packaging to reduce the risk of accidental ingestion.Manufacturer RecommendationsFinally, don’t overlook the advice from your device’s manufacturer. They’ve designed the product to work with specific batteries, so their recommendations are your best guide. If your manual suggests a CR1616 battery, stick to that size and voltage. Alternatives like the CR1620 or BR1616 can work, but only if they meet the same specifications.Reputable battery brands like Duracell, Energizer, and GP Batteries often provide detailed compatibility information. Choosing a trusted brand ensures better performance and reduces the risk of malfunctions. Avoid generic or unbranded options, as they may not meet safety or quality standards.If you’re unsure, reach out to the manufacturer or check their website for guidance. They might even list approved alternatives, saving you the guesswork.Note: Using an unapproved battery could void your device’s warranty. Always double-check before making a switch.Finding the right replacement for your cr1616 battery doesn’t have to be complicated. Options like the cr1620, CR2016, and BR1616 offer reliable performance, but you need to pick the one that fits your device. The cr1620 stands out as a great alternative with its higher capacity, as long as your device can handle the extra thickness. Always check your device’s manual and stick to trusted brands for the best results. Choosing the right battery ensures your gadgets stay powered and safe.FAQ### 1. Can I use a CR1620 battery in place of a CR1616?Yes, you can, but only if your device has enough space for the slightly thicker CR1620. It offers a higher capacity, so it may last longer. Always check your device’s manual to confirm compatibility before making the switch.

Summary: This comprehensive guide explores the critical differences between FPGAs and CPLDs, detailing their unique architectures, performance metrics, and ideal application scenarios. By comparing logic capacity, power consumption, and timing characteristics, it provides engineers with a practical framework for selecting the right programmable logic device for 2026 hardware designs.What is the Difference Between FPGA and CPLD?The primary difference between an FPGA (Field-Programmable Gate Array) and a CPLD (Complex Programmable Logic Device) lies in their architecture: FPGAs use a complex, look-up table (LUT) based structure ideal for high-capacity, parallel processing, while CPLDs rely on a simpler, macrocell-based architecture that provides deterministic timing and instant-on capabilities. In the field of digital electronic design, PLDs (Programmable Logic Devices) are becoming increasingly important due to their flexibility and rapid development capabilities. Among other things, the FPGAs and CPLDs are the two most prominent high-capacity programmable logic devices.While both devices provide programmable digital logic capabilities, they have significant differences in architecture, performance characteristics and application scenarios. It is critical for engineers and designers to understand these differences, as selecting the right device can significantly impact the cost, performance and development time of a project.In today's electronic designs, many functions that were traditionally implemented using multiple SPLD (Simple Programmable Logic Device) chips can now be integrated into a single CPLD; and complex functions that used to require custom ASICs (Application Specific Integrated Circuits) can now be realised through FPGAs. With the growth of the Internet of Things (IoT), artificial intelligence, and high-performance computing, the demand for these programmable devices is surging. In fact, the global FPGA market is projected to reach USD 15.2 billion in 2026, while the CPLD market is expected to grow to USD 0.68 billion in the same year.🔍 ‘Choosing an FPGA or a CPLD is not just a matter of capacity, it's a strategic decision for specific application needs.’This article will comprehensively analyse the technical differences between FPGAs and CPLDs, application scenarios, and provide a detailed selection guide to help you choose the most appropriate programmable logic solution for your project. Whether you are an experienced engineer, a student just entering the field, or a project manager seeking to optimise your product design, this guide will provide you with a valuable reference.How Do FPGA and CPLD Architectures Differ?FPGA and CPLD architectures differ fundamentally in their logic blocks, interconnects, and storage mechanisms. Although both FPGAs and CPLDs are programmable logic devices, their internal architectures and operating principles are fundamentally different. Understanding these differences is critical to the proper selection and application of these devices.Figure 1: Comparison of FPGA and CPLD architectures and functionsWhat is the Internal Architecture of an FPGA?The internal architecture of an FPGA consists of a vast array of Configurable Logic Blocks (CLBs), programmable interconnects, and Input/Output Blocks (IOBs).Logical block structure：Logic blocks in FPGAs are usually implemented based on look-up tables (LUTs), each of which is essentially a small memory cell that can implement arbitrary combinatorial logic functions.Interconnection resource：FPGAs use distributed, hierarchical interconnection networks that allow flexible routing but also increase cabling complexity.Storage Technology：Mainstream FPGAs use SRAM technology to store configuration data, the configuration is lost after power down, and external memory is needed to save the configuration; there are also FPGAs based on Antifuse (Antifuse) technology, which is programmed once and cannot be changed.Special resources：Modern FPGAs integrate a wealth of hardcore resources such as DSP blocks, embedded RAM, high-speed transceivers, and even complete processor cores.Figure 2: Schematic of FPGA internal architecture and componentsWhat is the Internal Architecture of a CPLD?A CPLD architecture is built around multiple macrocells connected by a central, predictable interconnect matrix.Macrocellular structure：Each macro cell contains a programmable AND-OR Array, optional registers, and output logic, enabling relatively complex combinational and timing logic.Interconnection method：CPLDs use a centralised fully-connected or nearly fully-connected interconnection matrix to make signal delays more deterministic and predictable.Storage Technology：CPLDs usually use non-volatile storage technology (e.g. EEPROM, Flash), where the configuration is maintained after power down and is ready for use on power up.Pin Assignment：CPLDs have more fixed pin assignments, usually each macrocell corresponds to a specific output pin.Figure 3: Basic CPLD architecture and organisationWhat Are the Key Technological Differences?FPGAs and CPLDs are fundamentally different in several key technology areas, particularly regarding logic implementation and configuration storage:CharacterisationFPGACPLDBasic building blocksLook-up table (LUT)-basedMacrocells (PAL-like structures)Logical implementation approachFine granularity, spreading resourcesWide with or array, centralised resourcesInterconnection ArchitectureDistributed, Multi-Level InterconnectionCentralised interconnection matrixConfiguration storageMainly SRAM (volatile)Mainly EEPROM/Flash (non-volatile)Timing CharacteristicsDelay is highly influenced by cabling and is highly variableDelays are fixed and predictableResource utilisationRelatively low due to wiring complexityHigher, almost all logic availableLogic DensityVery high (up to millions of gates)Medium (typically no more than 10,000 gates)Power consumption characteristicsRelatively high, with significant static power consumptionLow, especially static power consumptionThese architectural differences directly contribute to the differences in performance, application scenarios, and types of applicable projects between FPGAs and CPLDs. Next, we will analyse the performance characteristics, advantages and disadvantages of these two devices in detail.How Do FPGA and CPLD Performances Compare?Selecting the right programmable logic device requires a thorough understanding of the respective strengths and limitations of FPGAs and CPLDs. This section provides an in-depth analysis of the performance characteristics of both devices to help you make an informed choice in your project.What Are the Main Advantages of FPGAs?FPGAs offer unparalleled advantages in logic capacity and hardware-level parallel processing, making them ideal for complex digital systems.Key Advantages of FPGAsUltra-high logic capacity - Modern FPGAs can integrate millions of logic gates to support extremely complex designsParallel processing capability - Thanks to their array structure, FPGAs can enable true hardware parallel computingFlexible resource allocation - Flexible allocation of logic, storage and DSP resources on demandIntegration of special functions - Contains dedicated hard cores: DSP block, memory block, high-speed interface and processor coreHighly customisable - Can implement almost any digital circuit function, similar to a custom ASICThe FPGA architecture is particularly well suited for applications that require a lot of parallel processing, such as image/video processing, high performance computing and network packet processing. Its flexibility makes it ideal for prototyping and low-volume production applications as an alternative to expensive ASIC development. Modern FPGAs often integrate a variety of hard-core resources, such as ARM processor cores, Ethernet MACs, PCIe interfaces, etc., greatly simplifying system design.What Are the Limitations of FPGAs?Despite their power, FPGAs are limited by higher power consumption, complex timing convergence, and the need for external configuration memory.The main limitations of FPGAsRelatively high power consumption - Particularly static power consumption, not suitable for applications with strict power constraintsHigher costs - Higher cost per unit logic capacity than CPLDs and microcontrollersLonger start-up time - SRAM-based FPGAs require configuration time and do not work immediatelyHigh development complexity - Steep learning curve, requiring specialised HDL programming and complex toolchainDifficulty in timing analysis - Signal delay uncertainty is high and timing convergence can be a challengeThe complexity of FPGAs is a double-edged sword. On the one hand, it provides extreme flexibility, but on the other hand, it makes development more difficult. For simple control logic or applications that require instant startup, FPGAs may not be the best choice. In addition, the power consumption of FPGAs can be a serious obstacle in battery-powered applications.What Are the Main Advantages of CPLDs?CPLDs excel in providing deterministic timing, instant-on capabilities, and ultra-low static power consumption.Key Benefits of CPLDsDeterministic time series - Centralised interconnect structure provides stable and predictable signal delayInstant start-up capability - Non-volatile configuration, power-on ready to operate, no loading time requiredLow power consumption - Particularly good static power consumption for battery applicationsHigh I/O ratio - Provides more I/O pins relative to logic resourcesEasy to develop - Simple and clear architecture, easy to use development toolsCPLDs are particularly well suited for interface logic and control applications because of their simplicity and predictability. Their good timing characteristics make them ideal for high-speed interfaces and timing-critical applications. For systems requiring fast start-up, the immediate availability of CPLDs is an irreplaceable advantage.What Are the Limitations of CPLDs?The primary limitations of CPLDs include restricted logic capacity and a lack of dedicated hard-core resources like DSPs or embedded RAM.Major limitations of CPLDsLimited logical capacity - Typically no more than 10,000 equivalent logic gatesLimited memory resources - Lack of significant internal RAM resourcesLack of dedicated functionality - No specialised hardcore such as DSP blocks, high-speed interfaces, etc.Structural rigidity - With or array structure is not efficient enough for some algorithmsPoor scalability - Vulnerable to resource bottlenecks when adding functionalityThe biggest limitation of a CPLD is its capacity. As design complexity increases, it is easy to exceed the resource limitations of CPLDs. In addition, CPLDs are not suitable for applications that require large amounts of storage or complex mathematical operations because they lack the dedicated function blocks commonly found in FPGAs.By comparing the performance characteristics of FPGAs and CPLDs, it can be seen that they are each suitable for different types of application scenarios. In the next section, we will specifically analyse the best application areas for these two devices.What Are the Best Application Scenarios for FPGA vs CPLD?Because of their distinct architectural differences, FPGAs and CPLDs are suited for entirely different application scenarios in modern electronics.When Should You Use an FPGA?You should use an FPGA when your project requires high logic capacity, parallel data processing, or the integration of complex algorithms.High Performance Computing Acceleration - Accelerating computationally intensive tasks such as AI algorithms, scientific computing, and financial analysisImage and video processing - Real-time image filtering, computer vision, video codecs and enhancementData centre and network equipment - High-speed packet processing, network security, software-defined networkingCommunication system - Base station processing, software-defined radio, modemASIC Prototype Validation - Validating complex chip designs before mass productionAerospace and military - Mission-critical systems requiring high reliability and reconfigurabilityIndustrial control and automation - Real-time control and monitoring of complex industrial systemsFPGAs are particularly well suited for applications that require the processing of a large number of parallel data streams, and their hardware-level parallel processing capabilities can significantly improve performance. For example, in image processing, FPGAs can process multiple image regions at the same time, greatly speeding up processing.✨ "In data centres, FPGA accelerators can increase the performance of certain computing workloads by 5-10 times while reducing energy consumption by about 70%, making them ideal for green computing."Figure 4: Typical application scenarios of FPGAs in different industriesWhen Should You Use a CPLD?You should use a CPLD for system boot sequencing, interface bridging, and applications requiring strict deterministic timing.System boot and configuration control - Includes FPGA configuration managementInterface and Protocol Bridging - Connecting system components with different voltage standards or protocolsBus control and arbitration - Manage data flow between multiple devicesAddress decoding - Implement complex memory mapping and address translationState machine control - Implementing deterministic timing control logicLow-power portable devices - Applications with stringent requirements for power consumption and start-up timeOld design replacement and integration - Integration of multiple discrete logic devices into a single CPLDCPLDs excel in applications that require deterministic timing and high reliability. For example, during system startup, the CPLD can provide the necessary control signals before other components are ready, or manage the FPGA configuration process.💡 "CPLDs are often used as the ‘glue logic’ of a system, connecting components of different speeds, voltages or protocols to ensure that the whole system works in harmony. This role, although unassuming, is critical to system functionality."What Are Some Practical Application Case Studies?In real-world designs, FPGAs and CPLDs frequently operate alongside one another to maximize system efficiency and reliability.Case 1: Data Acquisition SystemIn a typical industrial data acquisition system:CPLD：Interface Control, Signal Conditioning, Address Decoding, Bus ManagementFPGA：High-speed data acquisition, real-time signal processing, data compression and pre-processingCase 2: Communications equipmentDivision of labour in modern communication equipment:CPLD：Power Management, Configuration Control, Interface Conversion, Basic Status MonitoringFPGA：Signal processing, complex protocol implementation, encryption/decryption, data flow managementCase 3: Embedded control systemIn Embedded Control Systems:CPLD：Simple timing control, status monitoring, safety shutdown logicFPGA：Complex control algorithms, sensor fusion, high-speed feedback controlIn practice, FPGAs and CPLDs are often not mutually exclusive choices, but rather work together in the same system, each playing to its strengths. For example, CPLDs can handle key control and interface functions of the system, while FPGAs are responsible for data-intensive processing tasks.In the next section, we provide a detailed selection guide to help you choose the most appropriate programmable logic device for your specific project.How to Choose Between an FPGA and a CPLD?Choosing between an FPGA and a CPLD requires a systematic evaluation of your project's logic scale, power constraints, and timing requirements.What Are the Key Decision Factors?The most critical decision factors include logic scale, startup requirements, power consumption, and cost sensitivity.Decision-making factorsPreference for FPGAsPreferences for CPLDsLogical ScaleLarge scale design (>10K gates)Small to medium scale design (<10K gates)Startup RequirementsAllow configuration delayRequires instant power-up to workPower Consumption RequirementsPower consumption is not a major considerationLow power consumption is criticalSignal TimingComplicated timing analysis acceptableDeterministic timing requiredStorage RequirementsLarge internal storage requirementsLow storage requirementsSpecialised FunctionsRequires DSP, high-speed interfaces, etc.Mainly general purpose logicDevelopment CycleLonger development cycle acceptableRapid development requiredCost SensitivityPerformance takes precedence over costCost is the key factorWhat is the Recommended Selection Process?To systematically select the appropriate device, follow this step-by-step evaluation process:Requirements Analysis: Clearly define the functional requirements and performance metrics of the projectResource Estimation: Evaluate the required number of logic gates, storage needs, and I/O quantityPerformance Constraints Definition: Determine timing requirements, power consumption limitations, and startup time requirementsScalability Considerations: Assess possibilities for future functional expansionDevelopment Resource Assessment: Consider the team's expertise and available development toolsCost Analysis: Consider development costs, unit costs, and lifecycle costsRisk Assessment: Evaluate technical risks and supply chain risks of different optionsDecision Making and Validation: Make decisions based on the above analysis, consider small-scale validationDecision Support Tool: FPGA vs CPLD Selection MatrixFor your project, score each factor (1-5 points), then use the formula below for weighted calculation:FPGA Suitability = Logic Scale×0.25 + Specialized Function Requirements×0.2 + Parallel Processing Requirements×0.2 + Memory Requirements×0.15 + Scalability Requirements×0.2CPLD Suitability = Deterministic Timing×0.25 + Quick Startup×0.2 + Low Power Consumption×0.2 + Development Simplicity×0.15 + Cost Sensitivity×0.2Compare the two scores and choose the technology route with the higher score.What Are Common Selection Misconceptions?Designers frequently make selection errors by focusing solely on gate count while ignoring timing, power, and long-term lifecycle costs.Common Misconceptions and CorrectionsMisconception 1: Selecting Based Only on Logic CapacityYou should consider architectural characteristics and application requirements comprehensively, not just the "gate count".Misconception 2: Over-specification DesignChoosing devices far exceeding requirements will increase cost, power consumption, and development complexity.Misconception 3: Ignoring Timing FactorsFPGA and CPLD have significant differences in timing characteristics, which directly affects design reliability.Misconception 4: Underestimating Development ComplexityFPGA projects typically require more expertise and development time; this factor should not be underestimated.Misconception 5: Ignoring Long-term CostsConsider the sum of development costs, unit costs, power consumption costs, and maintenance costs.In actual projects, many situations may require considering hybrid solutions, such as using CPLD for critical control logic and interfaces while using FPGA for complex data processing tasks in the same system.🔍 "Choosing the right programmable logic device is not just a technical decision, but also a strategic decision balancing cost, performance, power consumption, and development resources."What Are the Most Popular FPGA and CPLD Products in 2026?Based on different application scenarios and requirements, several FPGA and CPLD product families remain industry staples for both cutting-edge and legacy designs.Which FPGA Products Are Recommended?For high-performance and cost-optimized designs, the following FPGA families are highly recommended:Xilinx Artix-7: XC7A35T-1CPG236CKey Parameters: 33,208 Logic Cells, 1V Supply Voltage, Surface Mount 236-Pin LFBGA PackageKey Features: Cost-optimised FPGAs for small to medium-sized designs with low power consumption and good price/performance ratioApplicable Scenarios: Embedded vision, industrial control, automotive electronics, consumer electronicsReference price range: Medium-lowView DetailsIntel (Altera) Cyclone V: 5CGXFC7C6F23C7Key Parameters: 149,500 Logic Cells, 1.1V Supply Voltage, 484-BGA PackageKey Features: Highly integrated, built-in hardware floating-point DSP with PCIe Gen2 and high-speed transceiver supportApplicable Scenarios: Industrial Networking, Video Processing, Software Defined Radio, High Performance ComputingReference price range: Medium-highView DetailsLattice iCE40HX8K-BG121Key Parameters: 8,000 Logic Cells, Ultra Low Power, Small BGA PackageKey Features: One of the industry's lowest power FPGAs, instant startup and ease of useApplicable Scenarios: Portable Devices, Wearables, IoT Applications, Sensor HubsReference price range: lowView DetailsWhich CPLD Products Are Recommended?For low-power, instant-on control logic, these CPLD families continue to dominate the market:Xilinx CoolRunner-II: XC2C64A-7VQ44CKey Parameters: 64 Macrocells, 1.8V Supply Voltage, 44-TQFP PackageKey Features: Ultra-low power CPLD with fast start-up and good jitter controlApplicable Scenarios: Portable Device Control, Bus Interface, Protocol ConversionReference price range: lowView DetailsIntel (Altera) MAX II: EPM240T100C5NKey Parameters: 240 Logic Cells, 3.3V Operating Voltage, 100-Pin TQFP PackageKey Features: User flash technology, instant boot, rich I/O optionsApplicable Scenarios: System Control, Interface Bridging, Configuration ManagementReference price range: lowView DetailsLattice MachXO2: LCMXO2-1200HC-4TG100CKey Parameters: 1,200LUT, internal flash memory, 100-pin TQFP packageKey Features: Hybrid FPGA/CPLD Architecture, Instant Start, Flexible I/OApplicable Scenarios: Embedded control, interface management, real-time controlReference price range: mediumView DetailsWhen shopping for a product, it is recommended to consider the following factors:Development tool compatibility：Ensure your team is familiar with the relevant vendor's development environmentSupply chain stability：Assessing the long-term security of supply and life cycle of productsTechnical Support：Consider the quality of support and documentation provided by the manufacturerCommunity Resources：An active user community can provide a valuable development resourceUpgrade Path：Consider compatibility for future upgrades to higher performance productsConclusionIn this paper, we provide an in-depth analysis of the characteristics, strengths and weaknesses, and application scenarios of two important programmable logic devices, FPGAs and CPLDs. While both devices offer programmable logic capabilities, there are significant differences in architecture, performance, and areas of application.Summary of the selection guideSelecting an FPGA：When high logical capacity, complex functional implementations, large amounts of internal storage, dedicated hard-core resources, and scalability are requiredSelecting a CPLD：When deterministic timing, instant startup, low power consumption, simple development process and stable and reliable interface logic are requiredImportantly, FPGAs and CPLDs are not simply competing, but complementary technology solutions. In many complex systems, the two tend to work in tandem: CPLDs handle critical control and interface logic, while FPGAs are responsible for data-intensive processing tasks.With the growth of the Internet of Things, artificial intelligence, and edge computing, the demand for high-performance, low-power programmable logic will continue to grow. Understanding the characteristics of FPGAs and CPLDs and their optimal application scenarios will help engineers and designers make informed technology choices, optimise system performance, and reduce development risk.Ultimately, the choice of FPGA or CPLD should be based on the specific needs and constraints of the project, rather than simply going for the latest or most complex technology. Hopefully, the analysis and guidance provided in this article will help you make the best choice for your future projects.🔍 "In the field of digital design, understanding the differences in programmable logic devices and choosing the right technology path is often one of the key factors in the success of a project."Frequently Asked QuestionsWhich is faster, an FPGA or a CPLD?While FPGAs offer superior overall processing power and high-speed parallel execution for complex algorithms, CPLDs provide faster, more predictable pin-to-pin routing delays. For simple, timing-critical combinational logic, a CPLD often guarantees stricter deterministic timing, whereas an FPGA excels in high-throughput data processing tasks.Can a CPLD completely replace an FPGA?A CPLD cannot replace an FPGA for complex, data-intensive applications requiring thousands of logic gates, embedded memory, or DSP blocks. However, for simple glue logic, voltage translation, or system boot sequencing, a CPLD is often a more cost-effective, power-efficient, and reliable alternative to an over-specified FPGA.Why are FPGAs generally more expensive than CPLDs?FPGAs are more expensive because they feature significantly higher logic density, complex distributed interconnect architectures, and advanced integrated hard cores like DSPs and memory blocks. Manufacturing these high-capacity, SRAM-based chips requires advanced semiconductor nodes, whereas CPLDs use simpler, mature EEPROM or Flash-based macrocell architectures.Do CPLDs require external configuration memory?No, CPLDs do not require external configuration memory. They utilize non-volatile storage technologies, such as EEPROM or Flash memory, to retain their logic configuration even when powered down. This allows CPLDs to function instantly upon power-up, making them ideal for managing system boot sequences.FPGA vs CPLD Knowledge Cardbody {font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;line-height: 1.6;color: #333;background-color: #f8f9fa;}.container {max-width: 1200px;margin: 0 auto;padding: 20px;}h1, h2, h3, h4 {font-weight: 700;margin-top: 1.5em;margin-bottom: 0.8em;color: #2c3e50;}h1 {font-size: 2.5rem;margin-top: 1em;}h2 {font-size: 2rem;border-bottom: 2px solid #eaecef;padding-bottom: 0.3em;}h3 {font-size: 1.5rem;}h4 {font-size: 1.25rem;}p {margin-bottom: 1.2em;font-size: 1.05rem;}ul, ol {margin-left: 1.5em;margin-bottom: 1.2em;}li {margin-bottom: 0.5em;}.quote-box {background-color: #f1f8ff;border-left: 4px solid #2b6cb0;padding: 1em;margin: 1.5em 0;border-radius: 0 4px 4px 0;}.highlight-box {background-color: #fdf2e9;border-radius: 4px;padding: 1.5em;margin: 1.5em 0;box-shadow: 0 2px 5px rgba(0,0,0,0.1);}.comparison-table {width: 100%;border-collapse: collapse;margin: 1.5em 0;}.comparison-table th, .comparison-table td {border: 1px solid #ddd;padding: 12px;text-align: left;}.comparison-table th {background-color: #2b6cb0;color: white;}.comparison-table tr:nth-child(even) {background-color: #f2f2f2;}.image-container {display: flex;justify-content: center;margin: 2em 0;}.image-container img {max-width: 100%;height: auto;border-radius: 4px;box-shadow: 0 3px 6px rgba(0,0,0,0.16);}.caption {text-align: center;color: #666;font-size: 0.9rem;margin-top: 0.5em;}.faq-item {margin-bottom: 1.5em;border-bottom: 1px solid #eaecef;padding-bottom: 1em;}.faq-question {font-weight: 600;color: #2c3e50;font-size: 1.1rem;margin-bottom: 0.5em;}.faq-answer {padding-left: 1em;border-left: 3px solid #e5e7eb;}.product-card {border: 1px solid #e5e7eb;border-radius: 8px;overflow: hidden;margin-bottom: 1.5em;background-color: white;box-shadow: 0 2px 5px rgba(0,0,0,0.05);transition: transform 0.3s, box-shadow 0.3s;}.product-card:hover {transform: translateY(-5px);box-shadow: 0 5px 15px rgba(0,0,0,0.1);}.card-header {padding: 1em;background-color: #2b6cb0;color: white;font-weight: bold;}.card-body {padding: 1em;}.card-footer {padding: 1em;background-color: #f9fafb;border-top: 1px solid #e5e7eb;}.btn {display: inline-block;padding: 0.5em 1em;background-color: #2b6cb0;color: white;text-decoration: none;border-radius: 4px;font-weight: 500;transition: background-color 0.3s;}.btn:hover {background-color: #1e4e8c;}.tip-box {background-color: #e6fffa;border-left: 4px solid #38b2ac;padding: 1em;margin: 1.5em 0;border-radius: 0 4px 4px 0;}.warning-box {background-color: #fff5f5;border-left: 4px solid #e53e3e;padding: 1em;margin: 1.5em 0;border-radius: 0 4px 4px 0;}.video-container {position: relative;overflow: hidden;width: 100%;padding-top: 56.25%; /* 16:9 Aspect Ratio */margin: 2em 0;}.video-container iframe {position: absolute;top: 0;left: 0;bottom: 0;right: 0;width: 100%;height: 100%;border: none;}.toc {background-color: #f8f9fa;border: 1px solid #eaecef;border-radius: 4px;padding: 1.5em;margin: 1.5em 0;}.toc-title {font-weight: 600;margin-bottom: 1em;font-size: 1.2rem;}.toc-list {list-style-type: none;margin-left: 0;}.toc-list li {margin-bottom: 0.5em;}.toc-list a {color: #3182ce;text-decoration: none;}.toc-list a:hover {text-decoration: underline;}.sublist {margin-left: 1.5em;margin-top: 0.5em;}{ "@context": "https://schema.org", "@type": "Article", "headline": "FPGA vs CPLD: Comprehensive Architecture, Performance, and Selection Guide", "datePublished": "2025-05-07", "dateModified": "2026-03-31", "author": { "@type": "Organization", "name": "Kynix" }, "publisher": { "@type": "Organization", "name": "Kynix" }}{ "@context": "https://schema.org", "@type": "FAQPage", "mainEntity":[ { "@type": "Question", "name": "Which is faster, an FPGA or a CPLD?", "acceptedAnswer": { "@type": "Answer", "text": "While FPGAs offer superior overall processing power and high-speed parallel execution for complex algorithms, CPLDs provide faster, more predictable pin-to-pin routing delays. For simple, timing-critical combinational logic, a CPLD often guarantees stricter deterministic timing, whereas an FPGA excels in high-throughput data processing tasks." } }, { "@type": "Question", "name": "Can a CPLD completely replace an FPGA?", "acceptedAnswer": { "@type": "Answer", "text": "A CPLD cannot replace an FPGA for complex, data-intensive applications requiring thousands of logic gates, embedded memory, or DSP blocks. However, for simple glue logic, voltage translation, or system boot sequencing, a CPLD is often a more cost-effective, power-efficient, and reliable alternative to an over-specified FPGA." } }, { "@type": "Question", "name": "Why are FPGAs generally more expensive than CPLDs?", "acceptedAnswer": { "@type": "Answer", "text": "FPGAs are more expensive because they feature significantly higher logic density, complex distributed interconnect architectures, and advanced integrated hard cores like DSPs and memory blocks. Manufacturing these high-capacity, SRAM-based chips requires advanced semiconductor nodes, whereas CPLDs use simpler, mature EEPROM or Flash-based macrocell architectures." } }, { "@type": "Question", "name": "Do CPLDs require external configuration memory?", "acceptedAnswer": { "@type": "Answer", "text": "No, CPLDs do not require external configuration memory. They utilize non-volatile storage technologies, such as EEPROM or Flash memory, to retain their logic configuration even when powered down. This allows CPLDs to function instantly upon power-up, making them ideal for managing system boot sequences." } } ]}{ "@context": "https://schema.org", "@type": "ItemList", "name": "Popular FPGA and CPLD Products in 2026", "itemListElement":[ { "@type": "Product", "position": 1, "name": "Xilinx Artix-7: XC7A35T-1CPG236C", "description": "Cost-optimised FPGAs for small to medium-sized designs with low power consumption and good price/performance ratio." }, { "@type": "Product", "position": 2, "name": "Intel (Altera) Cyclone V: 5CGXFC7C6F23C7", "description": "Highly integrated, built-in hardware floating-point DSP with PCIe Gen2 and high-speed transceiver support." }, { "@type": "Product", "position": 3, "name": "Lattice iCE40HX8K-BG121", "description": "One of the industry's lowest power FPGAs, instant startup and ease of use." }, { "@type": "Product", "position": 4, "name": "Xilinx CoolRunner-II: XC2C64A-7VQ44C", "description": "Ultra-low power CPLD with fast start-up and good jitter control." }, { "@type": "Product", "position": 5, "name": "Intel (Altera) MAX II: EPM240T100C5N", "description": "User flash technology, instant boot, rich I/O options." }, { "@type": "Product", "position": 6, "name": "Lattice MachXO2: LCMXO2-1200HC-4TG100C", "description": "Hybrid FPGA/CPLD Architecture, Instant Start, Flexible I/O." } ]}

This article will introduce you some basic information of LEDs, you will learn what is LED, what are its characterics, how to and where to use it, how many kinds of LEDs are there, and so on. Catalog I. What is LED? 1.1 Brief Introduction 1.2 LED Structure 1.3 LED Limiting Parameters 1.4 LED Electrical Parameters 1.5  LED Optical Parameters II. LED Material III. LED Polarity IV. LED Characteristics V. LED Types VI. LED Trends VII. LED Application VIII. LED Light Decline Reasons IX. Complement: Blue LED FAQ I. What is LED? 1.1 Brief Introduction A tutorial on the basics of using LEDs (light emitting diodes). Polarity, forward voltage and current are discussed. A light-emitting diode (LED) is a kind of semiconductor electronic component that can convert electric energy into light energy. The electronic component appeared as early as 1962, emitting only low-light red light at an early stage, and later developed versions of other monochromatic lights, which now has light throughout visible light, infrared and ultraviolet light, and the luminosity has increased to a fairly high degree. With the development of technology, light-emitting diodes have been widely used in display, TV lighting decoration, and lighting sources. With the rapid progress of LED technology in the 1990s, its luminous efficiency exceeded the incandescent lamp, the intensity of light has reached the candlelight level, but also the color has covered the whole visible spectrum range from red to blue. This technological revolution from LED levels to beyond general-purpose light sources has led to new applications such as automotive signals, traffic lights, large outdoor panchromatic displays, and special lighting sources. The light-emitting diode is abbreviated as LED. It is made of a compound containing Ga, As, P, N, and so on. The making principle of LED is when the electrons and the holes are combined, the visible light can be radiated. It is one of the semiconductor diodes that can convert electrical energy into light energy. Compared with ordinary diodes, light-emitting diodes are composed of a PN junction and have unilateral conductivity. When a forward voltage is applied to the light-emitting diodes, the holes injected from the P region to the N region and the electrons injected from the N region to the P region are combined with the electrons and holes in the N region and the P region in the vicinity of the PN junction, respectively, to produce spontaneous emission fluorescence. The energy states of electrons and holes in different semiconductor materials are different. So when their electrons and holes are combined, the energy released is different, and the more energy is released, the shorter the wavelength of light.  Commonly used light-emitting diodes are red, green, or yellow. The reverse breakdown voltage of light-emitting diodes is greater than 5V. Its forward volt-ampere characteristic curve is steep, it must be used in a series current limiting resistor to control the current through the diode. The current limiting resistance R can be calculated using the following formula: R= (E－UF) / IF E is the power supply voltage, the UF is the forward voltage drop of the LED, and the IF is the normal operating current of the LED. The core portion of the light-emitting diode is a crystal sheet composed of a P-type semiconductor and an N-type semiconductor, and a transition layer is formed between the P-type semiconductor and the N-type semiconductor, referred to as a PN junction. In the PN junction of some semiconductor materials, if the injected minority carriers are combined with the majority carriers, the rest will be released in the form of light, that is, the electric energy is directly converted into light energy.  When the reverse voltage is applied to the PN junction, and the minority carriers are difficult to inject, so that no light is emitted. When the current flows from the LED anode to the cathode, the semiconductor crystal emits light from ultraviolet to infrared colors, and the intensity of the light depends on the current. 1.2 LED Structure In the following, a common LED white light as an example to illustrate the structure of the LED. As shown in Fig. 1 , the LED is mainly composed of the following parts: Fig. 1 LED structure Chip ( light emitting) Support: including substrate and heat dissipation base, pin, etc. (heat dissipation, conduction) Gold wire (conductive) Transparent resin (protecting grains, transmittance) 1.3 LED Limiting Parameters 1) Allowable power (PM): The positive DC voltage added to both ends of the LED and the maximum value of the current that flows through it. Beyond this value, the LED will be heated and damaged. 2) Maximum forward DC (IFM): Maximum positive DC current allowed to be added. Exceeding this value will damage the diode. 3) Maximum reverse voltage (VRM): Maximum reverse voltage allowed. If this value is exceeded, the LED may be corrupted. 4) Working temperature: Making a temperature range based on the requirement that LED works with. When exceeding this range, the LED will not work properly and will greatly reduce efficiency. 1.4 LED Electrical Parameters Fig. 2 wavelength of LED light 1) Spectral distribution and peak wavelength: Light generated by light-emitting diodes is not a single wavelength, and its wave growth body is shown in Fig. 2. It can be seen from the diagram that the intensity of λ =100 wavelengths is the largest, and the wavelength is the peak wavelength. 2) The luminous intensity of IV: Light-emitting diodes usually refers to the light intensity in the normal line direction (for cylindrical light-emitting diodes, the axis is its axis). Due to the luminescence intensity of normal LED is 2, the luminescence intensity is usually candela (MCD). 3) The spectral half-width (1/2): It indicates the spectral purity of the light-emitting tube. It refers to a difference between the two wavelengths corresponding to the peak intensity of the light in Fig. 3. Fig. 3 angular distribution of the luminous intensity of two different types of LED 4) The half-value angle θ1/2 and the angle of view: θ1/2 is the angle between the direction of light intensity value and the axial direction (normal direction) of the axial intensity value, and the half-value angle is twice the angle of view (or half-power angle). Fig. 2 shows the angular distribution of the luminous intensity of two different types of LED. The coordinate of the vertical (normal) AO is the relative luminous intensity, that is, the ratio of the luminous intensity to the maximum luminous intensity. Obviously, the relative luminous intensity of the normal direction is 1, and the larger the angle of the normal direction, the smaller the relative luminous intensity.  And this graph can get a half-value angle or an angle of view. 5) The forward working current (IF): It is the positive value of LED when it is normal. In practice,  you should select an IFM below 0. 6. 6) The forward operating voltage VF: Obtain the working voltage in the parameter table at a given forward current. In general, it is measured under IF=20mA. In VF, the forward voltage of the LED is 1.4 ~3V. And when the external temperature rises, the VF drops. 7) V-I characteristics: The relation between the voltage and current of the LED is shown in Fig. 4. When the forward voltage is less than a certain value (called threshold), the current is very small and does not emit light. When the voltage exceeds a certain value, the forward current increases rapidly with the increase of the voltage and is illuminated. The forward voltage, reverse current and reverse voltage of the LED can be obtained from the V-I curve. The reverse leakage current of the forward light emitting tube is lower than 10μA. Fig. 4 relation between voltage and current of LED Light-emitting diodes can be divided into four types: transparent, colored, and colorless. In addition, scattered light-emitting diodes are used to guide lights. (8) Main wavelength λD(nm): LED usually uses wavelength to represent color. The main wavelength is equivalent to the corresponding wavelength of the color seen by the human and is different from the peak wavelength of the luminous wavelength. The unit is nm (nanometer). The following are the wavelength parameters for the various luminous colors LED: Purple: 400～435nm Yellow-green: 560～580nm Blue: 435～480nm Yellow: 580～595nm Blue-green: 480～500nm Green: 595～610nm Green: 500～560nm Red: 610～760nm White: It is usually represented by the color coordinates below, or simply showed with warm white, right white, cold white. (9) Chromaticity diagram x and y It refers to the actual value of the LED glow color in the 2D orthogonal coordinate systems x and y, as shown in the following illustration: Fig. 5 chromaticity coordinate diagram 1.5 LED Optical Parameters Several important aspects of optical parameters of LED are: luminous flux, luminous efficiency, luminous intensity, light intensity distribution, wavelength. Luminous efficiency and luminous flux The luminous efficiency is the ratio of the luminous flux to the electric power, and the unit is generally lm/ W. The luminous efficiency represents the energy-saving characteristic of the light source, which is an important index to measure the performance of the modern light source. Luminous intensity and distribution The intensity of LED luminescence is a characterization of its intensity in a certain direction. Since the intensity of LED varies greatly in different spatial angles, we have studied the intensity distribution of LED. This parameter is of great practical significance and directly affects the minimum viewing angle of the LED display device. For example, the large-scale LED color display in gymnasiums and stadiums, if the distribution range of LED single tube is very narrow, then the audience facing the larger angle of the display screen will see the distorted image. And traffic signs also require a wider range of people to identify. Wavelength For the spectral properties of LED, we mainly look at whether its monochromatic property is good, and we should note that the main colors such as red, yellow, blue, green, white LED are pure or not. Because in many cases, such as traffic lights, the color requirements are relatively strict, but it is observed that in some LED lights, in reality, green looks blue and red is dark red. From this point of view, it is necessary and meaningful to study the spectral properties of LED. II. LED Material Generally, the five main raw materials of LED are wafer, bracket, silver glue, gold wire, epoxy resin. In 1993, at that time, Shuji Naka mura, who worked at Nichia Corporation in Japan, invented a blue light LED with commercial application value based on wide-gap semiconductor material nitride (GaN) and silicon nitride (InGaN), which was widely used in the late 1990s. In theory, the blue LED combined with the original red LED and the green LED can produce white light LED, but the white light LED is rarely made in that way. Most of the current white-light LED is made by covering the blue LED (near-UV, wavelength 450nm~470nm) with a yellowish phosphor coating, this yellowish phosphor is usually made by grinding the cerium-doped yttrium aluminum garnet (Ce3: YAG) crystal into powder and mixing it in a dense adhesive. When a LED chip emits blue light, some of the blue light is efficiently converted by this crystal into a mostly yellow light with a wider spectrum (the spectral center is about 580nm). Since the yellow light can stimulate the red and green light receptors in the naked eye, with the blue light, so that it looks like white light when these colors mixed, and its color is often referred to as moonlight. The method of making a white light LED was developed by Nichola Corporation and used in the production of white light LED from 1996. To adjust the color of the light yellowish light, it is possible to replace the Ce doped with the Ce3 +: YAG with other rare-earth elements, or even in a manner that replaces part or all of the aluminum in the YAG. Based on the characteristics of its spectrum, red light and green light are not as obvious as the broad-spectrum light source illuminated. In addition, due to the variation of the production conditions, the color temperature of the finished product of the LED is not uniform, therefore, the characteristics of the finished product should be distinguished during the production process. Another method of making a white LED is like a fluorescent lamp. An LED that emits near-ultraviolet light is coated with a mixture of two phosphors, one is europium which emits red light and blue light, and the other is copper and aluminum-doped with ZnS which emits green light. However, the epoxy resin in the adhesive will be cracked and deteriorated caused by the ultraviolet rays, the production difficulty is high, and the service life is also shorter. In contrast to that first method, it is less efficient (producing more heat) but its spectrum is better and the light looks better.  III. LED Polarity One of the longers of the two leads of the light-emitting diode is the positive pole, which should be connected to the positive pole of the power supply. Some LED leads are the same length, but there is a convex tongue on the shell, the lead near the small tongue is positive. LED Unidirectional Conductivity The LED can only be turned on in one direction, called forward bias, when the current flows, electrons, and holes recombine to emit monochromatic light, which is an electroluminescent effect, and the wavelength of the light and the color is related to the type of semiconductor material used and the element impurities to be incorporated. It has the advantages of high efficiency, long service life, difficult breakage, high switching speed, high reliability, and so on. The light-emitting efficiency of the white LED has been obviously improved in recent years. IV. LED Characteristics Compared with the incandescent bulb and the neon lamp, the light-emitting diode is characterized in that the working voltage is very low, and the working current is small, the impact resistance and the anti-seismic performance are good, the reliability is high, and the service life is long. The intensity of the light-emitting can be conveniently modulated by the intensity of the current passing through the modulation. Due to these features, the light-emitting diode is used as a light source in some photoelectric control devices and is used as a signal display in many electronic devices. Voltage LED uses a low-voltage power supply, the supply voltage is between 3~24V DC, depending on the product requirement, there are a few DC 36V or DC 40V, so it is a safer power supply than the use of high-voltage power supply, especially suitable for public places. Energy consumption The energy consumption is 80% less than the incandescent lamp with the same light efficiency and 40% less than the energy-saving lamp. Applicability Because of its small size, each unit of LED is a square of 3~5mm, so it can be fabricated into devices of various shapes and is suitable for the variable environments. Stability 100,000 hours, light attenuation is 50% of the initial. Response time The response time of the incandescent lamp is milliseconds and the response time of the LED lamp is nanosecond. Pollution No harmful metal mercury, etc. Color The red, yellow, green, and blue-orange multicolor luminescence can be realized by adjusting the energy band structure and the bandgap of the material conveniently through chemical modification. The operation voltage of the red light tube is small, and the operation voltage of red, orange, yellow, green, and blue light-emitting diodes is increased in turn. V. LED Types 1. Depending on the different packaging of the LED, the luminous surface and characteristics of the LED can be roughly divided into the following types: 1) Plug-in LED Plug-in LED, in addition to the common two-terminal monochrome LED, also includes three-terminal dual-color LED and four-terminal RGB full-color LED. 2) Surface-mount LED A surface-mount LED is usually available in 0402, 0603, 0805, 1206, and so on, in monochrome, two-colour, and RGB full-color type. 3) High power LED This type of LED is usually used for lighting source, and most of it is white-emitting LED. 4) LED digital tube By making more than one LED into each field and forming a characteristic letter or combination, you can display the 0/9 or English letters) or the bar-type to indicate progress or scale. 5) LED matrix screen The matrix form of LED can display Chinese and English letters. For example, the manufacturer's LED display screen is composed of these dot matrix screen modules. According to color, it can be monochrome, double color or RGB full-color type. 6) Smart LED This type of LED includes not only a LED core, but also a control circuit, IC, for specific functions, such as blinking flash. Or bus addressing controls the color of each point, and so on. 7) Special LED This kind of LED emits lights that are invisible to human eyes, such as infrared, ultraviolet, and so on. In daily life, we use the remote control as this kind of LED lamp. 2. Light-emitting diodes can also be divided into ordinary monochromatic light-emitting diodes, high brightness light-emitting diodes, ultra-high brightness light-emitting diodes, chronotropic light-emitting diodes, scintillation light-emitting diodes, voltage-controlled light-emitting diodes, infrared light-emitting diodes, and negative resistance light-emitting diodes, etc. There are two control modes of LED: constant current and constant voltage, and there are many dimming modes, such as analog dimming and PWM dimming. Most of the LEDs are controlled by constant current, so that the current of LED can be kept stable, and it is not easy to be affected to extend the service life of LEDs. Ordinary monochromatic light-emitting diode Ordinary monochromatic light-emitting diodes have the advantages of small volume, low operating voltage, small working current, uniform and stable luminescence, fast response speed, and long service life, and can be driven by various DC, AC, and pulse power sources. It belongs to the current-controlled semiconductor device, it needs to be connected to an appropriate current limiting resistor. The light-emitting color of ordinary monochromatic light-emitting diodes is related to the wavelength of light-emitting, and the wavelength of light-emitting depends on the semiconductor materials used in the manufacturing process. The wavelengths of red light-emitting diodes, amber light-emitting diodes, orange light-emitting diodes, and yellow light-emitting diodes are generally 650~700nm, 630~650nm, and 610~630nm respectively, and yellow light-emitting diodes are usually 585nm, green light-emitting diodes typically have a wavelength of 555~570nm. High brightness monochromatic light-emitting diode The semiconductor materials used in high brightness monochromatic light-emitting diodes and ultra-high brightness monochromatic light-emitting diodes are different from those of ordinary monochromatic light-emitting diodes, so the intensity of light-emitting is also different. Typically, high brightness monochromatic light-emitting diodes use materials such as gallium arsenide (GaAlAs) and ultra-high brightness monochromatic light-emitting diodes use phosphonium gallium arsenide (GaAsInP), etc. Common monochromatic light-emitting diodes use gallium phosphide (GaP) or phosphogallium arsenide (GaAsP). Variable color light-emitting diode The variable color light-emitting diode is a light-emitting diode capable of converting light-emitting colors. The color type of the variable color light-emitting diode can be divided into two-color light-emitting diodes, three-color light-emitting diodes, and multi-color (red, blue, green, and white) light-emitting diodes. According to the number of pins, the variable color light-emitting diode can be divided into two-terminal variable color light-emitting diode, three-terminal variable color light-emitting diode, four-terminal variable color light-emitting diode, and a six-terminal variable color light-emitting diode. Flashing light-emitting diode The flashing light-emitting diode is a special light-emitting device consisting of a CMOS integrated circuit and a light-emitting diode, which can be used for alarm indication and under-voltage and overvoltage indication. When using, the flashing light-emitting diode does not need to be externally connected with other components, so long as the appropriate direct-current working voltage is added at the two-end of the pins to flash and emit light. Voltage-controlled light-emitting diode Ordinary light-emitting diodes belong to current-controlled devices, and the current-limiting resistors with appropriate resistance values should be connected to each other when used. Voltage-controlled light-emitting diode integrates light-emitting diode and a current limiting resistor, which can be connected directly to both ends of the power supply when it is used. Infrared emitting diode  Infrared light-emitting diodes, also known as infrared emitting diodes, are light-emitting devices that can directly convert electrical energy into infrared light (invisible light) and can radiate it out. It is mainly used in various optical control and remote control emission circuits. The structure and principle of infrared light-emitting diodes are similar to those of ordinary light-emitting diodes, but the semiconductor materials used are different. Infrared light-emitting diodes are typically made of gallium arsenide (GaAs), gallium arsenide (GaAlAs), in a fully transparent or light blue, black resin package. VI. LED Trends With the development of the industry, technological breakthroughs, and the application of vigorously promote, LED lighting efficiency is also increasing and the price is constantly lower. The emergence of new combined tube sets also increases the power of a single LED. Through the continuous research and development of the same industry, the breakthrough of new optical design, the development of new lamps, the single product situation is also expected to be further improved. The improvement of control software also makes the use of LED lighting more convenient. LED, known as the fourth generation light source, has the characteristics of energy-saving, environmental protection, safety, long-life, low power-consumption, low heat, high brightness, waterproof, micro, shock proof, easy dimming, beam concentration, easy maintenance, and so on. It can be widely used in all kinds of the pilot light, display, decoration, backlight, general lighting, and other fields. Advantages of LED: high electro-optic conversion efficiency (close to 60%, environmental protection, long life (up to 100000 hours), low working voltage (about 3V), lossless life of repeated switches, small volume, less heat, high brightness, rugged and durable, easy dimming. The color is varied, the beam is concentrated and stable, and the start-up has no delay. Disadvantages of LED: high starting cost, poor color rendering, low efficiency of high power LED, constant current drive (special drive circuit required). In contrast, there are certain defects in traditional lighting. Incandescent lamp: low electro-optic conversion efficiency (about 10%), short life (about 1000 hours), high heating temperature, single-color, and low color temperature. Fluorescent lamps: low electro-optic conversion efficiency (about 30%), harmful to the environment (including mercury and other harmful elements, about 3.5-5mg/pic), non-adjustable brightness (low voltage can not start to glow), ultraviolet radiation, flicker phenomenon, large size, slow start, The increase in the price of the raw materials (the ratio of phosphors to costs increased from 10% to 60%~70%), the repeated switching affects the life. High-voltage gas discharge lamp: large power consumption, unsafe use, short life, heat dissipation problems, mostly used for outdoor lighting. VII. LED Application 1) LED display screen Since the mid-1980s, monochrome and multicolor displays have been introduced, most are text screens or animation screens at first. In the early 1990s, with the development of computer technology and integrated circuit technology, the video technology of LED display screen was realized. TV images can display directly on the screen, especially in the mid-1990s, the blue and green ultra-high brightness LED was successfully developed and put into production rapidly, which greatly expanded the application of outdoor screens with areas ranging from 100m to 300m. At present, LED display screen has been widely used in stadiums, squares, avenues, and even streets and shopping malls. 2) Traffic light Navigation lights have been using LED as a light source for many years, and the present work is to improve and perfect. Road traffic lights have made great progress in recent years, the technology is developing rapidly, and the application is developing rapidly. Its advantages are long life, power-saving and maintenance-free effect are obvious. At present, the peak wavelength of red LED is  630nm, yellow is 590nm and green is 505nm. It should be noted that the driving current should not be too large, otherwise the high temperature in the summer will affect the life of LED. 3) Automobile light Ultra-bright LED can be used as brake lamp, tail lamp, and direction lamp of the automobile, and can also be used in instrument lighting and in-car lighting. It has obvious advantages over an incandescent lamp in vibration resistance, power-saving, and service life. In addition, when it used as a brake light, the response time is 60ns, much shorter than the incandescent (140ms), which increases a safe distance of 4m to 6m on a typical highway. 4) LCD backlight As the backlight of liquid crystal display, LED can not only be used as green, red, blue, white, but also as a color-changing backlight. And many products have entered the production and application stage. 5) Decorative lighting Due to the increase in brightness of light-emitting diodes and the decline in price, coupled with the long life, power saving, easy drive and control than neon lights, and it can not only flash, but also change color during lighting, so it is made of various ultra-high brightness LEDs to decorate the tall buildings, bridges, streets and squares and other landscape in the cities, presenting a colorful, starlight and streamer scene. 6) Lighting source LED lamp has the advantages of anti-vibration, suitable for battery power supply, solid structure, and portability. It will have a great development in special lighting source. As lawn lights, buried lights, microscope field lighting, flashlights, medical lighting, museum or painting exhibition lighting, and reading table lamps. Application of monochromatic LEDs At first, LED was used as the indicator light source of the instrument. Later, various kinds of light-colored LEDs were widely used in traffic signal lights and large-area display screens, resulting in good economic and social benefits.  Automobile signal lamp is also an important field of the LED light source application. Due to the fast response speed (nanosecond level) of the LED, the driver of the trailing vehicle can be informed of the driving condition as soon as possible, thus reducing the occurrence of car rear-end collision accidents. In addition, LED lights in outdoor red, green, blue full-color display, key button miniature flashlight, and other fields have been used. VIII. LED Light Decline Reasons A. Quality issues of LED products 1) LED chip used in the physical condition is not good, and the brightness decay is faster. 2) There are defects in the production process. The heat dissipation of the LED chip can not be well derived from the pins, which leads to the increase of the attenuation of the chip because of the high temperature of the LED chip. B. Applying Problem 1) The LED is a constant current drive, and some of the LEDs are driven by the voltage to cause the LED to decay too fast. 2) The driving current is greater than the rated driving value. Advantages Small size: LED is basically a very small chip encapsulated in epoxy resin because it is very small and light. Low voltage: The power consumption of the LED is quite low, and generally speaking, the operating voltage of the LED is 2~3.6V, that is, only a very weak current is required to light normally. Long service life: The service life of the LED can be up to 100,000 hours under the proper current and voltage. High brightness, low heat: The LED uses cold light-emitting technology, which produces much lower heat than ordinary lighting lamps and lanterns of the same power. Eco-environment: LED is made of non-toxic materials, unlike fluorescent lamps containing mercury will cause pollution, and LED can also be recycled. IX. Complement: Blue LED Blue LED is a blue-emitting LED. In 2014, Yuji Nakamura and Hiro Amano won the Nobel Prize in physics for "inventing high-brightness blue light-emitting diodes, bringing energy-saving and white light sources." The invention of blue LED enables humans to gather together a three-primary colors LED, that emits trichromatic light so that it can produce enough bright white light with LED. The invention of the white LED lamp greatly improves the lighting efficiency of human beings. Principle Two breakthroughs in the late 1980s laid the foundation for the invention of blue LED: one was the development of epitaxial technology of gallium nitride and the another was the doping of P-type semiconductors. Blu LED contains several different (GaN) layers of gallium nitride. The lighting efficiency, adding indium (In) and aluminum (Al) in LED, is greatly improved. Meaning and controversy The invention of the blue LED enabled humans to use LED to produce white light that was bright enough, and the efficiency of the white LED is much higher than that of the incandescent lamp. White LED promotes the invention of all kinds of the LED display screen and also promotes the improvement of lighting efficiency. In particular, the latter makes it possible for humans to reduce carbon emissions and combat climate change. There are also concerns that blue light emitted by blue LEDs could do harm to the human eye because blue light can cause macular degeneration. Related Info: Triacs are at the heart of dimming controls for LED lighting. Triacs used in dimmers have normally been characterised and specified for incandescent lamp loads, which have high current ratings for both steady-state conditions and initial high in-rush currents, as well as very high end-of-life surge current when a filament ruptures. LEDs have much lower steady-state current than incandescents, and their initial turn-on current can be much higher for a few microseconds of each half-cycle of AC line voltage. Therefore, a spike of current can be seen at the beginning of each AC half-cycle. Typically, the current spike for an AC replacement lamp is 6 to 8A peak; the steady-state follow current is less than 100mA. An LED flood lamp for a recessed ceiling fixture designed to replace a typical filament unit that produces 750 lumens consumes only 13W in contrast with the old filament unit, which normally draws 65W. Designing an AC circuit for controlling LED light output is very simple when using the newest triac designs, such as the Littelfuse Q6008LH1LED or Q6012LH1LED Series, because the only components required are a firing/triggering capacitor, a potentiometer, and a voltage breakover triggering device. Two inverse parallel sensitive gate silicon-controlled rectifiers (SCRs), such as the Littelfuse S4X8ES1, can be used as the voltage breakover triggering device, allowing the controlling circuit to produce a wide range of light level outputs. Also, using these components as the triggering device allows achieving a low hysteresis control because two SCRs form a full breakback trigger.  If the application doesn’t demand a wide control range and low hysteresis, a simple variable light control may be designed using quadrac devices, such as the Littelfuse Q6008LTH1LED or Q6012LTH1LED Series (Figure 1). (A quadrac device is a special type of thyristor that combines a diac and a triac in a single package.) The circuit shown in Figure 2 minimises the component count by combining the diac triggering device and an alternistor triac in a single TO- 220 isolated mounting tab package. This control circuit allows a little lower full turn-on voltage due to higher VBO switching of the diac trigger device but offers a light dimming function that operates from 175° to <90° of each AC half-cycle. FAQ 1. What led means? light emitting diode. LED stands for light emitting diode. LED lighting products produce light up to 90% more efficiently than incandescent light bulbs. 2. What is LED used for? Made popular by their efficiency, range of color, and long lifespan, LED lights are ideal for numerous applications including night lighting, art lighting, and outdoor lighting. These lights are also commonly used in electronics and automotive industries, and for signage, along with many other uses. 3. How do LED lights work? An LED bulb produces light by passing the electric current through a semiconducting material—the diode—which then emits photons (light) through the principle of electroluminescence. Don't let that big word scare you! ... In contrast, an incandescent light bulb works by passing electricity through a small wire, or filament. 4. Why is it better to use LED lights? LED is highly energy efficient – Less heat, more light, lower cost. Use less electricity for the same light output - 85% less electricity when compared to conventional lighting and around 18% less electricity compared to CFL. ... LED can make a big impact on your energy use. 5. Why do LEDs fail? Temperatures are too high (or too low).When heat can't dissipate from the heat sink, it can cause lamps to fail prematurely. Also keep the surrounding environment in mind. ... Because LEDs emit light that decreases exponentially as a function of time and temperature. 6. What do LED light colors mean? The lower the color temperature, the warmer the light will appear, or the redder it will appear. The higher the temperature, the cooler the light will appear, or the bluer it will look. 7. What should be the biasing of LED? The LED works when the p-n junction is forward biased i.e., the p- side is connected to the positive terminal and n-side to the negative terminal. 8. Why are LED lights used mainly for lighting nowadays? Additionally, unlike Compact Fluorescent Lights (CFLs), LED lights do not contain mercury that can spill if dropped, making them a safer choice for household use. LEDs, which stand for Light Emitting Diodes, burn light 90 percent more efficiently than incandescent bulbs. 9. What are the disadvantages of LEDs? High up-front costs. Transformer compatibility. Potential color shift over lamp life. Performance standardization has not yet been streamlined. Overheating can cause reduced lamp life. 10. Why do my LED lights burn out so fast? The most common reasons for LED blowing out are high voltage, bad contacts, use of incompatible dimmer switch, or recessed lighting. Other causes include overheating due to not using the right fixtures, or simply a bad batch of lightbulbs! You May Also Like: Design LED strips on My House Walls Product Recommendation: LTL-4251NHBP LM3080N VC1510145UY3