The circuit below will make the outputs from your inverter, SMPS and all PWM circuits stable.
This is a simple feedback circuit for all PWM inverters and converter circuits. The circuit shows how to use optocouplers or photo transistors for feedback operations.
Photo transistor / optocoupler feedback circuit for PWM converters.
The circuit is as simple as it looks.The output of your converter is connected to the part labeled ''inverter/converter output'' .
The above circuit will work for voltages between 110V DC to 400VDC.
Resistors R16 and R18 can be increased when handling very high voltages (above 450V) AC.
Diode D6 and D9 should be ignored if the output of your converter is DC voltage.
D6 and D9 should be replaced with fast switching diodes like UF4007 or 1N4148 or better if your output is high frequency AC.
U18 can be replaced with any cheap optocoupler or photo transistor of your choice.
Pin 4 of the optocoupler is connected to 5 volts supply for 5V PWM ICs or between 5 to 12V supply for any other circuit which does not operate on 5V DC.
The part labeled "VFD" is connected to feedback pin of your IC. The ''GND" is connected to your negative supply so that your input will be isolated from your output to avoid shock.
The image below shows low voltage version of the above circuit. This is for low DC output voltages.
This is a simple feedback circuit for all PWM inverters and converter circuits. The circuit shows how to use optocouplers or photo transistors for feedback operations.
Photo transistor / optocoupler feedback circuit for PWM converters.
Feedback control circuit using optocoupler
The circuit is as simple as it looks.The output of your converter is connected to the part labeled ''inverter/converter output'' .
The above circuit will work for voltages between 110V DC to 400VDC.
Resistors R16 and R18 can be increased when handling very high voltages (above 450V) AC.
Diode D6 and D9 should be ignored if the output of your converter is DC voltage.
D6 and D9 should be replaced with fast switching diodes like UF4007 or 1N4148 or better if your output is high frequency AC.
U18 can be replaced with any cheap optocoupler or photo transistor of your choice.
Pin 4 of the optocoupler is connected to 5 volts supply for 5V PWM ICs or between 5 to 12V supply for any other circuit which does not operate on 5V DC.
The part labeled "VFD" is connected to feedback pin of your IC. The ''GND" is connected to your negative supply so that your input will be isolated from your output to avoid shock.
The image below shows low voltage version of the above circuit. This is for low DC output voltages.
Low voltage feedback circuit.
