Patent ID: 9490692
Filing Date: 2016-11-08
CPC Classification: H02M,H05B,Y02B

Claim Text:
1. A power factor correcting circuit for an AC direct lighting apparatus, the circuit comprising: a valley signal generating unit that receives a full-wave rectified AC input voltage signal, and compares an internal reference voltage signal and the AC input voltage signal to generate a valley signal; a reference voltage control unit that receives the valley signal, counts clock cycles of a clock signal to detect a frequency of the AC input voltage signal, and determines a frequency of a drive current to control a reference voltage signal based on the frequency of the drive current; and a reference voltage control clock generating unit that generates a pulse width modulation (PWM) signal associated with a pulse width of the reference voltage signal, and generates a reference voltage control clock signal based on the PWM signal and the reference voltage signal.