Patent ID: 7773399
Filing Date: 2010-08-10
Classification: H02M,Y02B

Abstract:
1. A control apparatus for controlling a voltage transforming apparatus including a transformer, power switching elements provided in a primary side of said transformer and performing on-operation and off-operation to invert a DC input voltage to an AC voltage, a synchronous-rectifying switching elements provided in a secondary side of said transformer and performing synchronous-rectifying control operation in synchronization with said power switching elements in order to rectify said AC voltage transformed by said transformer into a DC output voltage, and a smoothing circuit smoothing said DC output voltage, said control apparatus comprising: a driver circuit outputting first and second drive signals to said power switching elements, said power switching elements performing said on-operation while receiving said first drive signal, and performing said off-operation while receiving said second drive signal; a judging circuit making a judgment as to whether or not an output current of said voltage transforming apparatus is smaller than a specified current on the basis of a primary-side current flowing through a primary coil of said transformer before said second drive signal is outputted from said driver circuit in order to prevent said judging circuit from making said judgment on the basis of said primary-side current while said driver circuit outputs said second drive signal; and an inhibition circuit inhibiting said synchronous-rectifying switching elements from performing said synchronous-rectifying control operation when said judging circuit judges that said output current is smaller than said specified current.