Switching Power-Supply Device

摘要

A switching power-supply device includes a main switching element connected between a power-supply and an output terminal; a driving circuit that drives the main switching element; a capacitor that feeds power to the driving circuit; a charging circuit that charges the capacitor when the main switching element is switched from an on-state to an off-state; a switching control circuit that performs switching control of alternately switching the main switching element to the on-state and the off-state via the driving circuit; a voltage detection circuit that detects a voltage between both ends of the capacitor, and a driving control circuit that switches a state of prohibiting driving of the main switching element and a state of permitting driving of the main switching element, based on a difference between an output voltage output from the output terminal and a preset reference voltage and the voltage between both ends of the capacitor.

主权项

1. A switching power-supply device comprising:
a main switching element connected between a power-supply and an output terminal; a driving circuit that drives the main switching element; a capacitor that feeds power to the driving circuit; a charging circuit that charges the capacitor when the main switching element is switched from an on-state to an off-state; a switching control circuit that performs switching control of alternately switching the main switching element to the on-state and the off-state via the driving circuit; a voltage detection circuit that detects a voltage between both ends of the capacitor; and a driving control circuit that switches a state of prohibiting driving of the main switching element and a state of permitting driving of the main switching element, based on a difference between an output voltage output from the output terminal and a preset reference voltage and the voltage between both ends of the capacitor.