Patent ID: 8242703
Filing Date: 2012-08-14
Classification: H05B

Abstract:
1. A driving apparatus, suitable to drive at least a string of light emitting diodes, the driving apparatus comprising: a flyback power factor correction converter, for working in an operation mode according to a pulse-width modulation signal, and receiving an alternating current power and converting the alternating current power into a pulsating current; a harmonics-filtering unit, coupled to the flyback power factor correction converter and the string of light emitting diodes, for receiving the pulsating current and filtering out high-frequency harmonic components in the pulsating current so as to drive the string of light emitting diodes; and a control unit, coupled to the flyback power factor correction converter and the harmonics-filtering unit, for detecting the pulsating current by a means of current-transforming, and producing the pulse-width modulation signal according to the alternating current power and the detected pulsating current, wherein the control unit is further for reducing the peak-to-average ratio of the pulsating current by adjusting a duty cycle of the pulse-width modulation signal in response to a variation of the alternating current power.