Power factor correction circuit having on-period controlling

摘要

The present invention includes: a series circuit including a reactor and a switching element connected between the rectified-current output terminals of a rectifier; a series circuit including a diode and a smoothing capacitor for obtaining an output voltage, connected in parallel to the switching element; an error amplifier configured to detect the output voltage, amplify the error between the detected output voltage and a reference voltage, and output an error signal; a zero-current detector configured to output a signal when detecting that a reactor current flowing in the reactor has become zero current; a correction signal circuit configured to detect a switching current flowing in the switching element, and generate a correction signal corresponding to the detected switching current; and an ON-period control circuit configured to control the switching element's ON period in accordance with the error signal and correction signal, from when the zero-current detector detects the zero current.

主权项

1. A power-factor correction circuit, comprising:
a rectifier configured to rectify an input AC voltage; a first series circuit including a reactor and a switching element which are connected between rectified-current output terminals of the rectifier; a second series circuit including a diode and a smoothing capacitor for obtaining an output voltage, the diode and the smoothing capacitor being connected in parallel to the switching element; an error amplifier configured to detect the output voltage as a detected output voltage, amplify an error between the detected output voltage and a reference voltage, and output an error signal; a zero-current detector configured to output a signal when detecting that a reactor current flowing in the reactor has become zero current; a correction signal circuit configured to detect a switching current flowing in the switching element as a detected switching current, and generate a correction signal corresponding to the detected switching current; and an ON-period control circuit configured to control an ON period of the switching element with a control in accordance with the error signal and the correction signal, the control starting from when the zero-current detector detects the zero current.