SWITCHING POWER SUPPLY CIRCUIT

摘要

A switching power supply circuit includes a semiconductor switching element that is ON/OFF-controlled and controls current through an inductance, an output capacitor that stores power delivered from the inductance through a boost diode, a bypass diode that bypasses the inductance and delivers a DC voltage given to the inductance to the output capacitor, and a switching control section that ON/OFF-controls the semiconductor switching element. The switching power supply circuit includes in particular, an operation frequency reducing means that detects variation of the voltage generated on short-circuit of the bypass diode and lowers a switching frequency of the semiconductor switching element.

主权项

1. A switching power supply circuit comprising:
an inductance configured to receive a DC voltage; a switching element that controls a current that flows through the inductance; an output capacitor that stores an output voltage delivered from the inductance through a boost diode; a switching control section that ON/OFF-controls the switching element, such that the current that flows through the inductance increases in an ON state of the switching element and the current that flows through the inductance decreases in an OFF state of the switching element; a bypass diode that bypasses the inductance when the output voltage stored in the output capacitor decreases and delivers the DC voltage to the output capacitor; and an operation frequency reducing means for detecting a short-circuit of the bypass diode based on a current flowing through the switching element after a turning OFF of the switching element, and for reducing a switching frequency of the switching element upon the short circuit detection.