SWITCHING POWER SUPPLY AND METHOD FOR CONTROLLING VOLTAGE OF BULK CAPACITOR IN THE SAME

摘要

A switching power supply and a method for controlling a voltage of a Bulk capacitor in the switching power supply are provided. The switching power supply includes: a rectifying unit; a Bulk capacitor; a converter; a monitoring circuit; a control circuit, controlling discharging of the Bulk capacitor, being configured to perform controls such that the voltage across the Bulk capacitor maintains the peak value after the Bulk capacitor having been charged to a peak value of AC voltage, and to perform controls such that the Bulk capacitor discharges from a peak value when the instantaneous absolute value of the AC voltage is smaller than or equal to the preset voltage. Using the technical solution of the present disclosure, a discharging time of the Bulk capacitor can be shortened, and thereby the volume of the Bulk capacitor is reduced. Consequently, it is conducive to realize miniaturization of the switching power supply.

主权项

1. A switching power supply, comprising:
a rectifying unit having an Alternating Current (AC) side and a Direct Current (DC) side, the rectifying unit being configured to convert an AC voltage which is input to the AC side into a DC voltage which is output from the DC side; a Bulk capacitor connected to the DC side of the rectifying unit; a converter connected to the Bulk capacitor; a monitoring circuit connected to the AC side of the rectifying unit, the monitoring circuit being configured to detect and judge whether an instantaneous absolute value of the AC voltage is greater than a preset voltage; and a control circuit controlling discharging of the Bulk capacitor, connected to the monitoring circuit and the Bulk capacitor, the control circuit being configured to perform controls such that the Bulk capacitor maintains the peak value when the monitoring circuit judges that the instantaneous absolute value of the input AC voltage is greater than the preset voltage after the Bulk capacitor having been charged by the rectifying unit to a peak value of the AC voltage, and to perform controls such that the Bulk capacitor discharges from the maintaining peak value of the AC voltage so as to provide power to the converter when the monitoring circuit judges that the instantaneous absolute value of the input AC voltage is smaller than or equal to the preset voltage.