HIGHLY-EFFICIENT POWER FACTOR CORRECTION CIRCUIT AND SWITCHING POWER SUPPLY APPARATUS

摘要

When a standby signal is High, a Comp_stb signal that is overlapped with an AC waveform is output from an AC-COMP combining circuit in a COMP signal changing circuit, input into a PWM.comp, and compared with an output waveform of a ramp oscillator. Here, only when a peak of the Comp_stb signal is higher than a minimum voltage of the ramp oscillator is an OUT terminal output signal output from a control IC and a burst operation is performed. When the Comp_stb signal is lower than the minimum voltage of the ramp oscillator, the OUT terminal output signal is not output from the control IC because a reset signal of an RSFF remains High. Accordingly, a switching loss is reduced by operating a switching element in a burst mode when a switching power supply apparatus is in a lightly loaded or unloaded state.

主权项

1. A power factor correction circuit comprising:
a control integrated circuit (IC) including a control function to operate a switching element in a burst mode when a switching power supply apparatus connected to the control IC is in one of a lightly loaded or unloaded state, the control IC comprising:
means for generating an added output voltage by performing a weighted addition of a detected value of an input voltage input into the switching power supply apparatus to an output voltage of an error amplifier, wherein the input voltage is obtained by rectifying a power source during a standby period of time and the output voltage of the error amplifier is obtained by amplifying a difference between a detected value of an output voltage of the switching power supply apparatus and a reference value; andmeans for comparing the added output voltage generated by the means for generating an added output voltage with a carrier signal, and for generating, on the basis of an output of the comparing means, a signal that turns on/off the switching element of the switching power supply apparatus.