The Kynix Blog

SummarySeveral days ago, I was facing a challenge in my lab is--what is the perfect way to power breadboard projects?Situation and SolutionActually,I used breadboards to prototype almost all of my designs and I have always had less than ideal setups.Between my bench power supply, which has banana plugs, and the many wall transformer power supplies I have around the house with 2.1 mm plugs, I just do not have any options that are breadboard friendly.Here,just see the following photos,you will know that I end up with solutions in the past,well,it's not the easiest or prettiest of ways to connect to the breadboard.It does not take more than a casual glance at the pictures above to recognize that while functional, these are not ideal solutions. In both cases, the connections are too easy to accidentally dislodge and there is a risk of a short with the second one.  There had to be a better way.Before a design could be had, it needed some requirements.  As I pondered the requirements, I came up with the following technical specifications for this little device. I wanted to be able to optionally use my bench power supply or wall transformer and that each would have a secure connection to the breadboard.  I also wanted the ability to switch it on or off and have the option to power either both rails or just one with the external supply.As I worked through the design, it became a simple but effective solution.( I am excited)At first,I created a project in Eagle CAD around the connectors I needede,and designed the board shape to match up to the standard 830 point breadboards that I use in my lab. There were a handful of other features I wanted to include such as an optional filter cap, an on/off switch, and a power status LED.   As I got designing, I decided to refine a few of the features.  Many of my projects have more than one input voltage.  To facilitate this, I added a jumper block to connect or disconnect the second power rail for projects that need a dual voltage. Electronic partsHere just let me list the material we need in this project firstly: Deltron 571-0100 : Test Sockets SINGLE PCB SOCK BLKDeltron 571-0500 : Test Sockets SINGLE PCB SOCK REDKobiconn 163-7620E-E : DC Power Connectors PCB 2.1MMFCI / Amphenol 67997-472HLF : Headers & Wire Housings 72P HDRHarwin M7581-08 : Headers & Wire Housings JUMPER SOCKET OPEN TOP REDKOA Speer MF1/2DC1501F : Metal Film Resistors – Through Hole 1.5K 1% 100PPM Kingbright WP710A10SGD : Standard LEDs – Through Hole Grn 40mcd 568nm 40 deg DiffusedPanasonic ECA-1HM100I : Aluminum Electrolytic Capacitors – Leaded 10UF 50V ELECT M RADIAL If you would like to build one following me , these parts you can find from: https://www.kynix.com Schematic and ComponentsWith the basic design framework laid out, I started researching the components needed.  I personally tend to use the online Mouser catalog to help me sort through the vast quantities of components available.  I stuck with all through-hole components to make this project easier to assemble at home.  With all the parts identified, I returned to my project in Eagle CAD and found each of the components in my component libraries.  I connected them electrically as shown in the schematic below, and double-checked the design (an often under rated step in the design process). Board LayoutWith the schematic complete, it was time to move on to the board layout. Breadboards use a standard 0.1 inch pin spacing, but when I measured the spacing between the power busses, I noticed that they were slightly different.  After some trial and error, I realized that the actual spacing between the power bus pins was 1.85 inches O.C.  With the header pins placed at this location, the board outline was adjusted to create a proper fit.  After arranging the components, I added a ground pour to the top layer to simplify routing.  The Eagle autorouter made quick work of the rest of trace routing and the resulting board design looks like this:Board Assembly and TestingI ordered a batch of these boards from my favorite purple PCB vendor (OSHPark) online and assembled them.  I couldn’t be happier with the finished product.  The fit is perfect and they snap into the power bus tightly and stay put.  This little device has gone through extensive testing as I have been using these on all of my breadboard projects ever since I got the first one assembled.  They really work wonderfully!     Article edited by: kynix 

  This article will be divided into three parts--individual transformer , parallel transformer and redundancy requirements for bulk power transformers.     Catalog   I. Individual Transformer II. Parallel Transformer III. Redundancy Requirements for Bulk Power Transformers FAQ   I. Individual Transformer   Just see the following picture, it includes the protection for banks where fuses are used on the primary. Overall differential protection may be applied by using CTs in the transformer primary bushings for larger or important banks. The common connection is shown with delta on the source (primary) side and wye-grounded on the secondary side. Other possible connections: delta–delta, wye–wye, or primary-wye– secondary-delta. Figure 1 – Transformer protection without primary-side circuit breaker   About the analysis of power circuit, you can see the article: Analysis of Switching Power Supply Principle   Note: Secondary circuits should have 51 and 51N relays. Therefore, transformer secondary breaker and relays may be omitted unless another source connects to the secondary bus. 51N relay can be omitted with 51G available.   For transformer banks with primary breakers, the protection is summarized in Figure 2.   Relay 51G provides backup protection for secondary bus and feeder faults and must be time-coordinated, with other ground relays protecting the various feeder circuits on the secondary bus. Similarly, phase relays 51 must be coordinated with the phase relays on the feeders. The common connection is shown with delta on the source (primary) side and wye-grounded on the secondary side. Other possible connections: delta–delta, wye–wye, primary-wye– secondary-delta, three-winding, or autotransformer.   Figure 2 – Transformer protection with primary-side circuit breaker   "52S may be omitted in some applications requiring 151G to coordinate with and trip the secondary circuit devices if used." II. Parallel Transformer   The protection for transformer banks where the secondaries are connected together by a bus tie breaker is summarized in the following picture(a,b,c).   The arrangement shown is typical for large- or critical-load substations, especially for industrial plants. The loads are supplied from separate buses that are connected together by a bus tiebreaker (52T) that may be operated either normally closed (NC) or normally open (NO).   Figure 3a – Single line diagram of transformer and secondary bus protection for a typical double-source supply with secondary tie and breaker   If you operated NO, the protection of the first picture and second is applicable. If operated with 52T NC, the protection of the first picture and second is applicable with the secondary side modified. Figure 3b – Secondary protection with high-side fuses With the bus tiebreaker closed, there is a possibility for the interchange of power between the two sources. Here, current flows from one source through its transformer, the secondary buses, and back through the other transformer to the second source. Generally, this is neither desirable nor permitted.   "To prevent this operation, directional time–overcurrent relays (67, 67N) are applied to each transformer."   Figure 3c – Secondary protection with high-side breaker The single-line connections are shown in Figure 3b and Figure 3c, with complete three-line connections in the following figure.   Note: They operate only for fault current that flows into the transformer and trip the secondary breaker (52–1 or 52–2). This is also important in removing a secondary fault source for faults in the transformer bank. The phase relays (67) can be set on a low of the minimum tap.   Load current certainly flows through the relay, but normally not in the operating direction. The low tap continuous rating must not be exceeded by increasing the maximum load current. The 67-time setting must coordinate with the protection on the transformer primary. When used, the ground relay can be set on minimum setting and time, because coordination is not necessary.   Figure 4 – Three-line connections for reverse-phase and partial differential backup protection The inverse-time–overcurrent relays (51, 51N) provide bus protection and backup protection for the feeder circuits. These relays trip both 52–1 (or 52–2) and 52T. This is a partial differential connection and these units must be time-coordinated with the protection on the several feeders that are connected to the bus.   "Only two-phase relays are required, but the third relay (shown optionally in Figure 4) provides additional redundancy. When a ground differential is used, as illustrated in Figure 3c, 67N and 51N are omitted."   Ground-fault backup is provided by 51G, 151G, and 251G inverse-time overcurrent relays (Figure 3abc). Relay 251G provides bus ground-fault protection and backup for the feeder circuit ground relays. It must be time- coordinated with these. It trips the bus tie 52T, as the fault could be either on the bus or on the associated feeders.   If the fault continues to exist with the bus tie open, relay 151G trips breaker 52–1 (or 52–2). Thus, 151G must coordinate with 251G. If the fault persists, it is between the secondary breaker, in the transformer winding, or in the grounding impedance.   Relay 51G set to coordinate with 151G is the last resort. It trips the high-side or primary breaker to remove the transformer from the service.   III. Redundancy Requirements for Bulk Power Transformers   When transformers are connected to bulk power systems, redundancy requirements for related protection need to be addressed. To provide the required redundancy, two separate differential schemes may be applied.   "Redundancy for transformer faults may also be obtained by a differential scheme and sudden pressure."   In such an application, the sudden pressure protection needs to be supplied with additional protection for faults on the transformer bushings and leads, as sudden pressure devices will not respond to faults in these areas. Redundant schemes for disconnecting the transformer from the system when a high-side breaker is not applied can be obtained by using various combinations of the methods. Take an example, two separate transfer trip systems may be applied although they are expensive. A cheaper alternative is to combine a transfer trip scheme and a faulty switch. It may be possible to delay closing the fault switch for a few cycles to allow time for the transfer trip scheme, provided it is operational, to de-energize the failed transformer before the closing of the fault switch. This would spare the power system from being subject to a solid fault when the fault switch closes, whenever the transfer trip scheme works properly.   When a high-side breaker is applied and it fails to operate, breaker failure protection is required to enable isolation of a faulted transformer. The breaker failure scheme may require the application of a fault switch, transfer trip scheme, or a second interrupting device if other local breakers are not available to isolate the transformer.   FAQ     1. What is the use of transformer? Transformers are employed for widely varying purposes; e.g., to reduce the voltage of conventional power circuits to operate low-voltage devices, such as doorbells and toy electric trains, and to raise the voltage from electric generators so that electric power can be transmitted over long distances.   2. What are the 3 types of transformers? There are three primary types of voltage transformers (VT): electromagnetic, capacitor, and optical.   3. What is the basic principle of transformer? A transformer consists of two electrically isolated coils and operates on Faraday's principal of “mutual induction”, in which an EMF is induced in the transformers secondary coil by the magnetic flux generated by the voltages and currents flowing in the primary coil winding.   4. Does a transformer convert AC to DC? A transformer is built to transfer the energy from one circuit into another circuit by way of magnetic coupling. ... An alternating current creates a magnetic flux in the core on its way through the first winding, inducing the voltage in the others. It can convert high and low voltages, it cannot convert AC to DC.   5. What are the main parts of transformer? There are three basic parts of a transformer: a. an iron core which serves as a magnetic conductor, b. a primary winding or coil of wire and. c. a secondary winding or coil of wire.   6. What are the classification of transformer? Depending upon the type of construction used, the transformers are classified into two categories viz.: (i) Core type, and (ii) Shell type. Depending upon the type of service, in the field of power system, they are classified as: (i) Power transformers, and (ii) Distribution transformers.   7. Can a transformer work on DC? As mentioned before, transformers do not allow DC input to flow through. This is known as DC isolation. This is because a change in current cannot be generated by DC; meaning that there is no changing magnetic field to induce a voltage across the secondary component.   8. How do you convert a transformer? This conversion is made by winding two separate conductors around a common iron core. Applying an alternating voltage to the primary conductor produces current which sets up a magnetic field around itself. This is known as mutual inductance.   9. What are two components of no load current in transformer? The no-load current of a transformer consists of two components: The Magnetization Current iM is the current required to produce the flux in the transformer core. The Core-loss Current ih+e is the current required to make up for hysteresis and eddy current losses.   10. Which type of transformer core is most efficient? SHELL CORE. The most popular and efficient transformer core is the SHELL CORE, as illustrated in figure (4). As shown, each layer of the core consists of E- and I-shaped sections of metal. These sections are butted together to form the laminations.   11. What is the power factor of transformer? The power factor of a distribution transformer is between (0.75 to 0.80) when secondary is connected to u.p.f loads.   12. Why do we need Transformers? Transformers help improve safety and efficiency of power systems by raising and lowering voltage levels as and when needed. They are used in a wide range of residential and industrial applications, primarily and perhaps most importantly in the distribution and regulation of power across long distances.   13. What is the difference between a step up transformer and a step down transformer? A transformer that increases the voltage from primary to secondary (more secondary winding turns than primary winding turns) is called a step-up transformer. Conversely, a transformer designed to do just the opposite is called a step-down transformer.   14. Are transformers dangerous? There is no established evidence that the exposure to magnetic fields from powerlines, substations, transformers or other electrical sources, regardless of the proximity, causes any health effects.   15. Why transformer rating is in kVA not in kW? Copper losses (I²R) depends on current which passing through transformer winding while Iron losses or core losses or Insulation losses depends on Voltage. ... That's why the transformer rating may be expressed in VA or kVA, not in W or kW.    

CCD image sensors still remain preferable in some specialised application.Today I would like to talk something about CMOS image sensor technology. As the development of image sensor,CMOS technology is widely used in most machine vision applications.What's excited,perhaps as the concepts behind industry 4.0 become adopted more broadly--the need for mre capable vision systems has grown sharply. This is a video of CCD vs CMOS sensors Catalog   Historical and modern CMOS Improve productivity, support high bandwidth   readout Inherent flexible available About the high resolution Design the right products Conclusion FAQ Machine vision systems use images to gather information on a system or process and to then make decisions based on the image captured.While such systems are dependent upon lighting and software,the camera-and the image sensor within it-is the key component in the overall operation of the system,as well as the ability to improve manufacturing quality and increase productivity.At a high-level,a typical machine vision application involves som combinaton of basic measurement,counting or inspection functions.Objects may be assessed to confirm the number of objects present,to determine the number and size of features or their quality level.So machine vision could be used to not only determine that the proper number of holes have been drilled into an item, but also to verify the spacing and shape of each hole. Similarly, the location of an object may be determined in order for it to be picked up by a robot arm or to determine whether a feature is in the correct place. Other functions include reading a barcode, performing character recognition or measuring the level of a fluid.So machine vision could be used to not only determine that the proper number of holes have been drilled into an item, but also to verify the spacing and shape of each hole. Similarly, the location of an object may be determined in order for it to be picked up by a robot arm or to determine whether a feature is in the correct place. Other functions include reading a barcode, performing character recognition or measuring the level of a fluid.   Historical and modern CMOS Historically, machine vision systems have required CCD image sensors because of their high image quality and performance.  Today, however, CMOS image sensors have jumped to the forefront for many machine vision applications. Advances in CMOS pixel design have made the imaging quality available from this platform sufficient for a variety of different end uses.Modern CMOS image sensor platforms, such as that used in ON Semiconductor’s PYTHON family, are based on a global shutter pixel design that enables the capture of moving objects without the introduction of motion artefacts. In-pixel correlated double sampling provides low readout noise, while on-chip fixed pattern noise correction helps preserve image quality. Combined with a 10bit A/D converter and a dynamic range of 60dB, these features allow machine vision systems to leverage the intrinsic advantages of a CMOS platform in their operation.   Improve productivity, support high bandwidth readout With many machine vision applications looking to operate at ever higher speeds in order to increase productivity, image sensors must support high bandwidth readout. The output architecture of the CMOS platform enables this as additional digital outputs can be added to increase the available bandwidth. For example, the use of up to 32 separate LVDS outputs enables high resolution PYTHON devices to realise bandwidths that exceed those of modern computer interfaces, including 10Gbit Ethernet or USB 3.1. The ability to output at up to 80frame/s from a 25Mpixel device is well beyond the capabilities of standard CCD designs. Inherent flexible available The inherent flexibility available in CMOS output designs allows the frame rate to be further increased when operating in Region of Interest (ROI) mode, where only a portion of the image sensor array is read out. With proper design considerations, the speed increase when operating in this manner can scale by both the x and y dimensions of the ROI, enabling faster frame rates than can be realised when using a more standard CMOS output design, which only scales the x dimension. Consider the frame rates from the PYTHON 5000 image sensor compared to theoretical frame rates from a similar 5Mpixel sensor using a standard CMOS output. At full resolution, both designs would provide approximately 100frame/s, but when reading out a 1280 x 720 pixel ROI, the the PYTHON device’s frame rate increases to almost 600frame/s, while the standard output design would increase to only 300frame/s. This can be an important differentiator.    About the high resolution While high resolution can provide finer detail, this must be balanced by making sure that too much information is not captured, which would slow data processing. In addition to having the right number of pixels, they need to be in the appropriate aspect ratio for the application. For example, an aspect ratios of 1:1 is often used in pick and place applications to maximise image capture across the full field of view. Different spectral sensitivities, such as colour, monochrome and extended near infrared (NIR), may also be required to optimise the imaging system for the application. In order to do this, a camera manufacturer will look for an integrated family of image sensor products that includes multiple resolution nodes and colour options to support a portfolio of products.The PYTHON family has more than 40 options, with resolutions ranging from VGA to more than 25Mpixel. These devices are available in multiple configurations, including monochrome, Bayer Color and extended NIR sensitivities. Selected devices are available in low-power configurations or with removable tape to protect the image sensor during the camera assembly process.   Design the right products Avent Silica offers a range of evaluation kits to help designers understand the performance available from the PYTHON family of image sensors.These kits include an image sensor,the appropriate sensor headboard,FPGA evaluation board and software and accessories.The Flexible design also allows the evaluation hardware to be use with other PYTHON devices by purchasing additional image sensors.After identifying the most appropriate image sensor, designers then need to consider the remainder of the camera design. Complementary products from ON Semiconductor include embedded boards, power and signal chain components that allow engineers to choose between modular solutions and the flexibility of a discrete design. If a machine vision system needs to be brought to market quickly, it may not be possible to build it from the ground up. For those applications, Avnet Silica products such as the PYTHON-1300-C camera module. Based on the PYTHON 1300 colour image sensor and featuring a 0.5in SXGA CMOS image sensor with a resolution of 1280 x 1024 pixels, the module can be combined with Avnet Silica’s MicroZed Embedded Vision Carrier Card and the Smart Vision Development Kit to provide a complete hardware design, leaving the designer to only write the application software.\ Conclusion Because of the combination of image quality,bandwidth,image flexiblity and configuration flexiblity available from MOS image sensors has accelerated adoption of this technology in machine vision applications.What's celebrating,The imaging capabilities of such devices has ushered in a new level of performance and functionality for industrial imaging and CMOS sensor based imaging is now suitable for use in almost every type of design.   FAQ   1. How does a CMOS image sensor work? Unlike CCD sensors that use high-voltage analog circuits, CMOS sensors employ a smaller digital circuitry that uses less power, and are in principle free from smear (vertical white streak in the image taken under bright light) and blooming (corruption of images such as white spots).   2. Which sensor is better CCD or CMOS? CMOS sensors have thousands. This means that CMOS cameras can read out incredibly fast, even 100X faster than a comparable CCD. For long-exposure applications that is not so important, but it is especially important for video cameras.   3. Is CMOS a full frame sensor? "Full frame" is a description of sensor size, sort of... "CMOS" is a name for semiconductor technology used to make sensors. So, they are definitely different, and not comparable.   4.What is CMOS sensor type? A CMOS sensor is an electronic chip that converts photons to electrons for digital processing. CMOS (complementary metal oxide semiconductor) sensors are used to create images in digital cameras, digital video cameras and digital CCTV cameras.   5. What is the function of image sensor? An image sensor is a device that allows the camera to convert photons – that is, light – into electrical signals that can be interpreted by the device. The first digital cameras used charge-coupled devices, facilitating movement of the electrical charge through the device so it could be modulated.   6. What is difference between CCD and CMOS? The biggest difference is that CCD sensors create high quality images with low noise (grain). CMOS images tend to be higher in noise. CCD sensors are more sensitive to light. CMOS sensors need more light to create a low noise image at proper exposure.   7. What CCD means? Charged Coupled Device. Stands for "Charged Coupled Device." CCDs are sensors used in digital cameras and video cameras to record still and moving images. The CCD captures light and converts it to digital data that is recorded by the camera. For this reason, a CCD is often considered the digital version of film.     8. What is CCD and CMOS? CCD (charge coupled device) and CMOS (complementary metal oxide semiconductor) image sensors are two different technologies for capturing images digitally. Each has unique strengths and weaknesses giving advantages in different applications.   9. Is CMOS sensor good? CMOS sensors traditionally have lower quality, lower resolution and lower sensitivity. CMOS sensors are just now improving to the point where they reach near parity with CCD devices in some applications. CMOS cameras are usually less expensive and have great battery life.   10. How does a CCD work? Fundamentally, a charge coupled device (CCD) is an integrated circuit etched onto a silicon surface forming light sensitive elements called pixels. Photons incident on this surface generate charge that can be read by electronics and turned into a digital copy of the light patterns falling on the device.  

SummaryRihito Kuroda, a researcher at Tohoku University in Japan who develops UV imagers in his lab said“There's important information hidden in the UV,”. However, this information has been difficult to capture; silicon doesn't absorb ultraviolet wavelengths very well, and other semiconductors that play well with ultraviolet light make slow imagers with low frame rates. But that’s about to change. This week at the International Electron Devices Meeting in San Francisco, two research groups presented ultrathin, flexible UV sensor designs they hope will help make these devices more widespread.  UV images reveal spots that presage rot on mushrooms, dark lines along flower petals that guide insects to nectar, and clouds of acetone in water. And with their relatively short wavelengths, UV sensors could be well suited to more precise navigation for flying swarms of tiny drones. The research aimed at making UV sensors from specially formulated paperA group from King Abdullah University of Science and Technology in Saudi Arabia presented their research aimed at making UV sensors from specially formulated paper. Electrical engineering student Chun-Ho Lin explained that it’s difficult to make flexible UV sensors because they heat up under the high-energy rays. Typical flexible substrates, like plastic and paper, can’t wick away that heat quickly enough. He and other electrical engineers in Jr-Hau He’s lab made thermally conductive, UV-sensitive paper by combining boron nitride nanosheets with cellulose fibers. Flexible sensors made from this formulation can take the heat, withstanding temperatures up to 200 degrees Celsius. What’s more, they are blind to wavelengths above the deep UV band.Other researchers are sticking with silicon, but using graphene to help it along. Yang Xu, an electrical engineer at Zhejiang University in China, says there are good reasons to work with silicon, even though in its native state it is a strong reflector of UV rays. Silicon photodetectors can work quickly, enabling higher frame rates, and they can draw on a vast manufacturing infrastructure. Xu says his philosophy is, “Why not help silicon do better?” With that in mind, his team is pairing the semiconductor with graphene, which absorbs UV light like a champ. To make flexible silicon-graphene UV photodetectors, the Zhejiang University group uses etching and rubber stamps to transfer ultrathin silicon microstructures to a flexible plastic substrate, then coats the silicon with graphene and adds electrodes. This photodetector is blind to visible light, because the silicon layer is just 20 nanometers thick and cannot absorb it. This ultrathin device is flexible and performs as well as state-of-the-art UV photo detectors, says Xu. His lab is currently working on shrinking the size of the photodetectors to improve their resolution. 

SummaryHappy new year! The year of 2017 has become a past tense,whatever you experienced in the last year,let's celebrate the 2018's coming together ! Today I would like to show you a power projects about the high power voltage current  bridge driver using IR2153&IGBT. Project PhotoThis is a high power voltage current half bridge driver. About IGBT and IR2153IGBT based alf bridge board has been designed for multiple applications,like induction heater driver,tesla coil driver,DC-DC converters,SMPS etc. High current and high voltage IGBTs are used to serve high power requirements. IGBT NGTB40N120FL2WG from ON semi and IR2153 from Infineon semiconductor are important parts of the circuit, IR2153 is a gate driver IC including inbuilt oscillator, 40A/1200V IGBT can handle large current.  Gate driver circuit works with 15V DC and load supply 60V DC to 400V DC.  The IR2153D(S) are an improved version of the Popular IR2155 and IR2151 gate driver ICs, and incorporate a high voltage half-bridge gate driver with a front end oscillator similar to the industry standard CMO 555 timer. The IR2153 provides more functionality and is easier to use than previous ICs. A shutdown feature has been designed into the CT pin, so that both gate driver outputs can be disabled using a low voltage control signal. In addition, the gate driver output pulse widths are the same once the rising under voltage lockout threshold on VCC has been reached, resulting in a more stable profile of frequency vs time at startup. Noise immunity has been improved significantly, both by lowering the peak di/dt of the gate drivers, and by increasing the under voltage lockout hysteresis to 1V. Finally, special attention has been played to maximizing the latch immunity of the device, and providing comprehensive ESD protection on all pins.Oscillation frequency adjustable by onboard Trimmer potentiometer, frequency spans approx. 12 KHz to 100 KHz, duty cycle 50%. Note: Please take appropriate precautions as this power supply uses lethal voltages! Features Load Supply 60V to 400V DCGate Driver Supply 15V DCFrequency Span 12 KHz to 100 KHz, Other frequency range possible, alter R5, PR1, C8Duty Cycle Approx. 50%PR1: Trimmer Potentiometer to set the frequencyCN3: Logic Supply 15V DCCN1: Supply DC InputCN2 : L1 Load SchematicTesla Coil ExampleParts List  Connections Note 1: The circuit is provided with few extra components which may be used as per application requirement other components can be omitted as stated in BOM 2: Frequency span is determined by CT Capacitor (C8) and Trimmer Pot value, refer to datasheet for appropriate value for required frequency span. C8 1Kpf, R5=7k5 and PR1=50K provide frequency span 12 kHz to 100 kHz. 3:  Other Mosfet or IGBT can be used as per your current and voltage requirement. 4: This board also can be used as half bridge driver using IR2101/IR2104 and Mosfet, Header CN3 Pin1 HIN, Pin2 LIN, Omit following components R5, PR1, C8 to use IR2101/IR2105 5: IGBTs require large size heat sink. 

SummaryRecently the designers found a approach to improve speed,cost and linearity of A-D conversion--Using  ‘voltage-to-frequency converters’(VFCs) to perform A-D conversions in data acquisition systems that require strict monotonic response,high resolution and reuced noise and moderate speed.The VFC produces a pluse train with frequency proportional to the input voltage.Then a microcontroller or logic converts fre quency into a number by opening a gate for a fixed amount of time and counting how many.However,this approach is not perfect.the main drawback is that to increase speed, designers have to run the VFC at high frequency, which deteriorates linearity.   Design Ideathe design idea of this aproach reverses things.A circuit converts input voltage into a proportional time interval;then,the micro uses that interval to count pulses coming from its internal clock.The results are impressive:1.Good linearity as the voltage-to-period converter runs at low frequency2.Faster A-to-D conversion due to the high value of the clock frequency3.Potentially simpler program or logic, as it only has to count clock pulses, gated by the circuit4.Low priceCircuit and Voltage IssueThe key is that increasing the count frequency does not affect linearity of the A-to-D conversion, while increasing the frequency of the VFC always means worse linearity.Just see the following picture: This picture is a circuit about modified VFC,where the input voltage VIN and the reference voltage VREF swap their roles. The R1-R2 network shifts the input voltage so it is always more positive than the reference voltage and maintain proper operating conditions. The circuit uses all switches of the 4066 part: two in parallel build S1 to reduce the effect of imperfect switch flatness on linearity, one switch goes for S2, and the last switch is part of the start-up circuit, paralleling CINT, and controlled by the logic during initialization.As the input voltage changes from 0 to 5V, the output period changes from 78 to 578µs. Integration capacitor CINT and the threshold level of the one-shot’s Schmitt input do not participate in the period vs voltage relation.Filling the period with 10MHz clock pulses generates numbers from 780 to 5780 – one count per millivolt. Linearity is one count or ±0.02%, which is not a surprise when the maximum frequency is only 12.8kHz. The maximum time of the A-to-D conversion is 578µs. This is 8.65 times faster compared to the case of a 1MHz VFC, where it would take 5,000µs to count 5,000 pulses of 1µs. The interface program is short and simple.Calibration involves some back and forth due to the shift of the input voltage: adjust sensitivity to 100µs/V using the trim-pot of the one-shot. The nominal duration of the one-shot pulse is 26µs. Cancel the 780 count offset in the controller.The following table  shows that the V-to-P approach is significantly better than the V-to-F one (Refs 3, 4). Surprisingly, no chip-maker offers this type of converter.