Driving circuit for power switching device, driving method thereof, and switching power supply apparatus

Abstract

A driving circuit includes a generator configured to generate a driving signal having plural levels of voltage at which a power switching device is turned on. The driving circuit also includes a switching controller configured to switch between the plural levels of voltage at which the power switching device is turned on. The driving circuit further includes a load current detector configured to output a load current detection signal to the switching controller, the load current detection signal indicating whether or not a current flowing through the power switching device exceeds a threshold, wherein the switching controller is configured to perform the switching based on the load current detection.

1 . A driving circuit, comprising:
 a generator configured to generate a driving signal having plural levels of voltage at which a power switching device is turned on;   a switching controller configured to switch between the plural levels of voltage at which the power switching device is turned on; and   a load current detector configured to output a load current detection signal to the switching controller, the load current detection signal indicating whether or not a current flowing through the power switching device exceeds a threshold,   wherein the switching controller is configured to perform the switching based on the load current detection signal.   
     
     
         2 . A switching power supply apparatus, comprising:
 a power switching device that switches voltage of an input signal;   a driving circuit that drives said power switching device;   a transformer that transforms voltage generated by driving said power switching device into a different voltage; and   a rectifying and smoothing circuit that rectifies and smoothes the transformed different voltage and outputs the rectified and smoothed voltage,   wherein the driving circuit includes:   a generator configured to generate a driving signal having plural levels of voltage at which the power switching device is turned on;   a switching controller configured to switch between the plural levels of voltage at which the power switching device is turned on; and   a load current detector configured to output a load current detection signal to the switching controller, the load current detection signal indicating whether or not a current flowing through the power switching device exceeds a threshold,   wherein the switching controller is configured to perform the switching based on the load current detection signal.