PWM LED-Driver 0-100 percent using 2 OpAmps

313

04:55:36

Funny.... I have posted this circuit many months ago. Suddenly it is listed as private. That's why I post it again.

Push the switch to start the circuit. 
Use the Poti on the left to regulate the output of the MOSFET between 0% (off) and 100%(on) using PWM. 
***UPDATE***Middle Poti changes offset and the right one the frequency (~430Hz -  3kHz). 
I have  build this circuit on a breadboard. I had to adjust the window resistors on both sides of the Potentiometer (the 33k resistors) to make it work correctly. Also the oscillating frequency is different, but that doesn't matter. The circuit works fine in real.

published 10 years ago

GingerKing

10 years ago

Good Job. Add another pot to change the frequency. Its easy and comes in handy when running RC circuits or boost regulators.

ManuelPeh

10 years ago

Thanks. I have tried it. But EC "can't find solution" in some situations. So I have left it this way.

GingerKing

10 years ago

If you add a switch to the 12v supply, leave it open, start the simulation and close the switch then it should find a solution. In case you didn't know

ManuelPeh

10 years ago

Thanks very much GingerKing. No, I did not know that. Noob you know. :) Btw., your circuit are very interresting. I have watched them today. Nice nice, hope you don't get tired going on! 👍

ManuelPeh

10 years ago

Ok, added a switch and two pots. Middle pot chooses the voltage window (offset) and the right one changes the frequency.

rich11292000

10 years ago

A pmos should go in place of the nmos.

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