Switching power supply with reduced energy transfer during a fault condition

摘要

A switching regulator (18) for use in a switching power supply (10) detects a fault condition by looking for presence of feedback signals during a timer period. If feedback is present but less than a threshold value during the timer period, then the switching power supply (10) is operating normally. If feedback is not present during the timer period, then the switching power supply is in a fault condition. One way of implementing the timer is to charge and discharge by-pass capacitor (23). The timer period is the time for the VCC voltage to drop from a maximum value to a predetermined threshold. When a fault is detected, the gate drive signal from the switching regulator is disabled for a period of time before attempting auto-restart.