Abstract: A constant-current, current-programmed dc-to-dc converter includes a controllable switch and an inductor. The switch is rendered conductive in response to a recurrent clock signal, and nonconductive in response to a comparison of a voltage representing the inductor ramp current with an output voltage error signal from a high impedance source, which establishes an output voltage control feedback loop. An overcurrent limiting circuit includes a current sensor having a low output impedance which produces a load current representative signal. The load current representative signal is applied to an amplifier having a low output impedance and which includes a diode in its feedback loop to maintain it nonsaturated. A second diode is connected to the output of the amplifier and to the high impedance output terminal of the error voltage source to close a current limiting degenerative feedback loop which swamps the error voltage when the second diode becomes conductive due to excess load current.

Abstract: Saturation is avoided in the core of the transformer used for direct conversion in a single-ended dc-to-dc converter of the type using auxiliary flyback conversion through a plural-winding inductor. This is done by resetting the core with a winding threading the core, through which winding the secondary current of the plural-winding inductor passes.