Abstract: Disclosed is a system of paralleled switching power supplies designed and controlled to have substantially identical output voltages and impedances so as to share the load equally. The output voltage of each supply is controlled to decrease linearly with increased output current, and the individual power supplies and their control circuits are designed and controlled to behave as identically as possible under the expected service conditions such that, under any given set of conditions, the output voltages and impedances of the several individual power supplies can be expected to be substantially identical and therefore they can be expected to share the load substantially equally. Provisions are made to make the control of the individual power supplies substantially independent of variations in the resistance of the power cables connecting them to the common load.

Abstract: A pulse width modulated power supply contains an inverter circuit which includes a plurality of transistors connected to a drive transformer. The transistors are caused to conduct alternatively to provide a switching waveform at an output, which waveform is filtered to provide a regulated DC output voltage.The supply includes means for preventing switch-through of the transistors while providing regulation of the output voltage to keep the same constant over a wide range of operating conditions.Other means provide an efficient drive for the inverter as well as the capability of operating the supply at either of two input voltage levels.