Diagram | S36012 Power Supply Circuit

S-360-12

While specific internal schematics can vary by manufacturer, most units follow a standard Half-Bridge or Flyback switching topology. Typical S36012 Circuit Stages

• Pin 7 (Vcc): Connected to auxiliary winding of transformer via a start-up resistor network.

Short Circuit / Overload

| Protection | Circuit Method | Action | | :--- | :--- | :--- | | | Current sensing via a 0.01Ω/5W wirewound resistor on the negative output rail. Voltage across it is fed to pin 16 (Error Amp 2) of TL494. | If voltage exceeds ~0.3V (≈30A), TL494 shuts down output. Hiccup mode. | | Over-voltage (OVP) | A Zener diode (13V) + SCR (C106) across output. | If output >13.5V, Zener triggers SCR, shorting output and blowing the primary fuse. | | Over-temperature | NTC thermistor bonded to the main heatsink, connected to TL494 shutdown pin. | Shuts down at >85°C. Automatically resumes when cool. | s36012 power supply circuit diagram

• No output: check EN pin, VIN decoupling, and ground continuity.
• Excessive ripple/heat: increase output capacitance, use lower DCR inductor, verify switching node layout.
• Output overshoot on load dump: add faster output ceramics or snubber per datasheet.
• Stability issues: follow datasheet compensation recommendations or add small ESR (via electrolytic) to output.

• Components: Fuse (F1 – 10A/250V), NTC Thermistor (SCK-105), MOV (14D471K), X-capacitor (0.33µF/275V), Common-mode choke (T18x10x7).
• Function: The fuse and MOV suppress surges. The common-mode choke with X/Y capacitors filters differential and common-mode noise from feeding back into the mains.