The author started building this project to replace the failed power supply in he’s Heath Warrior amplifier. By reverse engineering some Dell computer supplies, he soon had a rough schematic diagram sketched out. Here is a short description on how this power supplies work: When the supply operates on 120 Volts, half of a full wave bridge rectifier charges a pair of filter capacitors to + and – 150 Volts, respectively.
These voltages are alternately switched across the primary winding of the power supply transformer by a pair of transistors connected in a “totem pole” configuration (A half-bridge” circuit.) The secondary windings produce various voltages which are rectified, filtered and distributed to the loads in the computer. Samples of the +5 and +12 volt output are used for feedback to the voltage regulator circuitry.
After some building and thinkering, the project was finished. The power supply was tested, and was able to handle 1KW of power by lighting 10 x 100 w lightbulbs.