sg3525 pwm problem for 50hz 12v to 220v pwm....

[d@nny]

i have the following schematic for 50hz 12v to 220v dc. i have foud it from internet but not yet tested it. The problem is that how i can adjust pin no.2 the duty cycle by giving feed back from output 220 to obtain pwm? does it only require modification on the pin 2 or whole circuit needs to be changed?

 

[FvM]

A feedback amplifier and compensation circuit involving pins 1,2 and 9 should be supplemented. The 230 VAC output needs to be rectified for the feedback.

 

[d@nny]

Please can u provide me a schematic ? i also have download the following diagrame

thanking you in anticipation

 

[FvM]

I don't have a schematic, but the feedback circuit of your example can basically work. The feedback amplifier should probably have a PI rather than a pure I characteristic for faster response.

 

[d@nny]

please tell me which schematic i used i post 3 schematics. which one should i use

 

[kabiru]

Hi,you can simply used step down transformer let's say 6-9volt from your final output and rectified it,use simple pot and control pin 1 of your SG3525.

 

[FvM]

You have only posted one schematic with AC voltage feedback, it's almost similar to what kabiru suggested.

 

[atripathi]

refer the circuit at SG3525 DC Converter 12V to +35V,-35V | Circuit Project Electronic
This has PI feedback loop, Refer Pin 9,1, 2 connections.

 

[FvM]

This has PI feedback loop, Refer Pin 9,1, 2 connections.

Yes. The time constants would be however scaled by a factor > 100 according to the 60 Hz operating frequency of your inverter.