Silvio
Well-known member
but i think i need to get feedback from error amp.
when we don't use error amp the op-amp just turn on and off.
It means that error amp just turn on and off the tl494
But when we use feedback for error amp it change dutycycle every time to have stable output.
Is it true?
PWM works like this. If you have a small pulse width then the output has low current but voltage will still rise to the peak so for this reason you should have a minimum load attached to bring the voltage to the desired output. When the load is increased the voltage tend to drop so the error amplifier widens the pulse width hence it will deliver more current to the output until it brings the voltage again to the desired level. This happens at a very fast speed say at 3000 times per second.
Try to do some reserch on the net to learn more about the subject. Try wikipedia and write Pulse width voltage regulation
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