Switching type regulated power supply

Abstract

A power supply of the switching type having alternately conductive switching transistors coupled to the primary of a transformer, in which a control circuit insures that the switching transistors are never simultaneously conductive. The control circuit utilizes two multivibrators having a common timing circuit for generating pulses which have their leading edges synchronized and are such that the width of the pulses from one multivibrator is never less than the width of the pulses from the other multivibrator, thus insuring a minimum dead time interval between the on times of the alternately switched transistors. Circuit protection is provided by sensing and feedback of the current through the transformer secondary or primary windings, and by sensing the saturation voltage across the switching transistors, to regulate the duty cycle of the pulses generated by the control circuit. Power for the control circuit and the switching transistor drive circuitry is provided from the secondary of the transformer. A starting circuit, after a delay, provides operating voltage to the control and driving circuitry by charging of the capacitors to provide temporary power supply to said circuits until the power therefor can be supplied from the secondary winding of the transformer. The integrated output voltage derived from at least a portion of the secondary winding is duty cycle regulated by a saturable reactor circuit operating in the avalanche mode.