Being the control circuit which controls the switching operation of switching transistor of the separately excited type DC/DC converter which generates the Drive voltage which is

摘要

PROBLEM TO BE SOLVED: To provide a control circuit for an externally commutated DC/DC converter that directly monitors output voltages, detects short-circuit state, and performs overcurrent protection.;SOLUTION: A switching controller 10 for a control circuit 100 controls the switching operation of a switching transistor Tr1 of an externally commutated DC/DC converter 210. A voltage comparator 30 compares an output voltage Vout with a threshold voltage Vth, to detect short-circuit state. The switching controller 10 interrupts the operation of the switching operation of the switching transistor Tr1, when the voltage comparator 30 detects a short-circuit state, after the elapse of a predetermined starting time, since the starting of the externally commutated DC/DC converter. Detection of short-circuit state by the voltage comparator 30 is invalidated, before the elapse of a predetermined starting time. The switching controller 10 commences again starting the externally commutated DC/DC converter, after having detected the short-circuit state and interrupted the switching operation of the switching transistor Tr1 for a predetermined interruption time.;COPYRIGHT: (C)2007,JPO&INPIT