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 Â±15 V (or Â±12 V) at 1 A. Since linear three-terminal regulators are used for the low-current outputs, either Â±12 V or Â±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.
The lower MOS. Q6, since it is ground referenced. is directly driven from the control !C.