SWITCHING POWER SUPPLY APPARATUS

摘要

A switching power supply apparatus of a current-resonance type, including a first switching element and a second switching element connected in series, a series circuit of a resonant reactor and a resonant capacitor connected in parallel to the first switching element or the second switching element, a control circuit configured to alternately turn on and off the first switching element and the second switching element, and a load detection circuit. The load detection circuit includes a shunt circuit which shunts a resonant current flowing through the resonant reactor and resonant capacitor connected in series to obtain a shunted current, converts the shunted current to a first voltage signal, and outputs the first voltage signal, a switching circuit which switches between the first voltage signal and a second voltage signal of a ground level to generate a third voltage signal, and an averaging circuit which averages the third voltage signal.

主权项

1. A switching power supply apparatus of a current-resonance type, comprising:
a first switching element and a second switching element connected in series; a series circuit of a resonant reactor and a resonant capacitor connected in parallel to the first switching element or the second switching element; a control circuit configured to alternately turn on and off the first switching element and the second switching element; and a load detection circuit, including:
a shunt circuit which shunts a resonant current flowing through the resonant reactor and resonant capacitor connected in series to obtain a shunted current, converts the shunted current to a first voltage signal, and outputs the first voltage signal;a switching circuit which switches between the first voltage signal and a second voltage signal of a ground level to generate a third voltage signal; andan averaging circuit which averages the third voltage signal.