ATX PC Circuit

This atx 200w PC power supply circuit with main chip TL494. Similiar the most atx PC power supply output 200 W use this circuit.

When somebody pushes the power button on CPU, pin PS-on running. Transistor Q10 closes and Q11 closes. Then C15 aktif to charging through R15 and on the pin 4 IC1 begins decrease voltage to zero thanks to R17. Due to this voltage is maximum pulse-width continuosly increased and main power supply goes run.