Drive led from 220v rectified

199

02:00:18

First block is simple buck converter which pulls down voltage.

Because of the transient of buck converter could burn LEDs I added the opamp which limits current to 0.5A.

published 12 years ago

hurz

12 years ago

Ok, but you should increase rise and falltime for the converter. Because EC has problems to simulated infinite values for analog circuits. And than you can go back to 100kV/V for the opamp and lower the transistor hfe to a more realistic value like 100 and decrease the base resistor to 47Ohm or so. Keep on designing

lucagessi

12 years ago

Thamk you

lucagessi

12 years ago

I set rise and fall time to 5%. 1kv\v could be realistic for a darlington.

hurz

12 years ago

Yes, 1k is even a bit low for most darlington

Secuture

12 years ago

Hmmm isn't op amp a right choice for a led buck drive?? Itself require some stable power supply at most cases even a symmetrical one if someone not handle yet well a single supply circuits for opamps. This complicate design cuz a some cap dropper based power suppl with zener will be required and if we make a cap dropper we already have power for led only some cap adjust for few miliamps more will be need. U catch what i have in mind ??

lucagessi

12 years ago

I don't know cap dropper circuit. I'll watch it.

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