Patent ID: 6366479
Filing Date: 2002-04-02
Classification: H02M

Abstract:
A DC-DC converter comprising a transformer having a primary winding and a drive winding, said transformer being an autotransformer which has a tap provided in said primary winding of said autotransformer;a first output smoothing circuit connected between an end and said tap of said primary winding and with output terminals; a switching element connected in series to a DC power source and said primary winding; a control circuit for generating outputs to drive said switching element, said control circuit being operable and inoperable when voltages of a trigger level and an inoperative level respectively are applied on said control circuit; a trigger circuit for supplying electric power from said power source at the beginning of operating said control circuit; a second output smoothing circuit connected to said drive winding for supplying electric power to said control circuit; and a voltage control circuit for detecting output voltage of said drive winding under a trigger level for driving said control circuit, said voltage control circuit being operable to decrease the output voltage of the second output smoothing circuit to an inoperative level for ceasing operation of the control circuit when said second output smoothing circuit is electrically charged to the trigger level through said trigger circuit.