SWITCHING POWER SOURCE

摘要

PURPOSE:To make energies supplied to a load average by a method wherein a switching duty ratio of the switching power unit of a chopper system is decreased as increased when an impressed voltage is low. CONSTITUTION:The electric power unit for an electronic range or the like causes GTO12 to chop a pulsating a voltage in a high frequency through a primary winding of a high voltage transformer 5 and causes the energies of the transformer 5 to oscillate a magnetron 9. An output of a voltage detector 17 is supplied to a duty control circuit 19 to control the duty ratio of the GTO12 by generating a signal such as making the ON-period short when the instantaneous voltage being large. Accordingly, an area by one continuity period of wave forms of the current flowing in the GTO12 can be made almost equivalent, and the electric power less in ripple is transferred to the magnetron 9 leaving it in the pulsating state to enable the average to be contrived.