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Showing posts from October, 2019

USE OF POINTER TABLE IN GENERATING SINEWAVE

Demystifying The Use of Table Pointer in SPWM - Application in Sine Wave Inverter I have previously written quite a few articles on sinusoidal pulse width modulation (SPWM). I've discussed about how to generate the sine table, how to implement it, how to practically generate the SPWM signals (with example code) and also how to implement feedback with simple sine table manipulation with table pointer instead of complex PID control. All these methods have one thing in common regarding the implementation - use of the sine table and its control with the table pointer. Whether you use or implement feedback or not, the table pointer is used to access and retrieve values from the sine table. It took quite a while for me to understand exactly how the table pointer works in this case – to retrieve data from the sine table and feed it to the PWM module and generate the required output 50Hz frequency (you can use any frequency but my requirement is 50Hz). While many have seen my post

Using the TLP250 Isolated MOSFET Driver

Using the TLP250 Isolated MOSFET Driver - Explanation and Example Circuits I’ve already shown how to drive an N-channel MOSFET (or even an IGBT) in both high-side and low-side configurations in a multitude of ways. I’ve also explained the principles of driving the MOSFETs in these configurations. The dedicated drivers I’ve shown so far are the TC427 and IR2110. Some people have requested me to write up on MOSFET drive using the very popular TLP250. And I’ll explain that here. The TLP250, like any driver, has an input stage, an output stage and a power supply connection. What’s special about the TLP250 is that the TLP250 is an optically isolated driver, meaning that the input and output are “optically isolated”. The isolation is optical – the input stage is an LED and the receiving output stage is light sensitive (think “photodetector”). Before delving any further, let’s look at the pin configuration and the truth table. Fig. 1 - TLP250 Pin Configuration Fig.

Using the TLP250 Isolated MOSFET Driver

Using the SG3525 PWM Controller - Explanation and Example: Circuit Diagram / Schematic of Push-Pull Converter PWM is used in all sorts of power control and converter circuits. Some common examples include motor control, DC-DC converters, DC-AC inverters and lamp dimmers. There are numerous PWM controllers available that make the use and application of PWM quite easy. One of the most popular of such controllers is the versatile and ubiquitous SG3525 produced by multiple manufacturers – ST Microelectronics, Fairchild Semiconductors, On Semiconductors, to name a few. SG3525 is used extensively in DC-DC converters, DC-AC inverters, home UPS systems, solar inverters, power supplies, battery chargers and numerous other applications. With proper understanding, you can soon start using SG3525 yourself in such applications or any other application really that demands PWM control. Before going on to the description and application, let’s first take a look at the block diagram and

H-BRIDGE SINEWAVE INVERTER BOARD WITH PIC16F72 WITH ADJUSTABLE CHARGE CURRENT

                   The Sinewave board can drive up to 10kVA inverter single phase Feel free to ask an question on the inverter

E-TECH SOLAR INVERTER SOLUTION

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