The power supply uses two VN4000A 400-V MOSPOWER FETs in a half-bridge power switch configuration. Outputs available are + 5 Vat 20 A and ±15 V (or ±12 V) at 1 A. Since linear three-terminal regulators are used for the low-current outputs, either ±12 V or ±15 V can be made available with a simple change in the transformer secondary windings. A TU94 switching regulator IC proVides pulse-width modulation control and drive signals for the power supply. The upper MOSPOWER FET, Q7. in the power switch stage is driven by a simple transformer drive circuit.
100Khz-multiple-output-switching-power-supply - schematic

The lower MOS. Q6, since it is ground referenced. is directly driven from the control !C.

Recommended videos

  • Learn More About Switched-Mode Power Supplies and their Difference from Linear Power Supplies
    Duration: 4:28.
  • SMPS Tutorial (1): Introduction - Switched Mode Power Supplies and Power Conversion
    Duration: 18:38.
  • SMPS Tutorial (4): Boost Converters, Flyback Voltages, Switched Mode Power Supplies
    Duration: 13:06.