SG/KA3525 PWM Controller

Introduction

Hey everyone in this session we learn how to use KA/SG3525 IC to make PWM controller circuit having feedback, low voltage and over heating protection.

Components

So lets take look at components we need to make this circuit -

1.SG/KA3525 IC

2.LM358 IC

3.LM555 IC

4.10K NTC

5.Variable resistor - 10K*4, 500K*1

6.16-pin, 8-pin IC Base

7.Capacitors - 1nF*2, 100nF*4, 2.2uF*1)

8.Resistors - 100R*1, 220R*2, 1K*10, 5.6K*1, 10K*6, 15K*2, 100K*1

9.BC547*1

10.LED*2

11.Push Button*1

12.Zero PCB

Working                                                                                                                           

In this circuit we used SG3525 to make PWM controller and use to drive mosfets or IGBT to make converters and this features adjustable frequency from 30Hz to 70KHz & adjust the duty cycle from 0% to 50% main thing you noticed that it consists of PC817 optocoupler which is used to correct or adjust output without having any direct contact, it is galvanic isolated. By using inverting and non-inverting pins and 5v reference pins to make feedback circuit and also this IC have SD-pin i.e. shut down pin, this pin used to protect from having low battery or Mosfet getting over heating or any kind of short circuit. The 5v reference pin is used to power LM358 and LM555 IC.

LM358 is used to Sence input voltage and mosfet temperature to stop PWM and main role of LM555 is acts as bi-stable multivibrator, when LM358 detects low voltage then it triggers 555 IC and it stays off untile reset push button is pressed to again activates the output.

Testing

First we need all components as shown then on breadboard place all components and test its properly working and then make on zero PCB. 

You can adjust frequency and duty cycle with the help of preset given in the circuit like in the picture.

                                            

            

                                                                                                                                                           

After all done this is the half version i.e. PWM and feedback controller     

Circuit Diagram                                                                                                              

Here is the final circuit diagram of KA3525 with LOW voltage, Over heating and Short circuit protection. In circuit you can see pin 16 which connected with vcc pins of LM358 and LM555 IC.

Hey friends if you have any problem regarding the circuit, components then ask me in comments.