Nanjing University of Aeronautics and Astronautics

Fsp Technology Inc.

Xinbo Ruan

Ming Xu

Kai Yao

Beibei Wang

Linlin Gu

A driving apparatus is provided and configured to suit driving at least a string of light emitting diodes (LEDs). The driving apparatus includes a flyback power factor correction (PFC) converter, a harmonics-filtering unit and a control unit. The flyback PFC converter works in an operation mode according to a pulse-width modulation (PWM) signal and receives an AC power so as to convert the AC power into a pulsating current. The harmonics-filtering unit is coupled to the flyback PFC converter and the string of LEDs, for receiving the pulsating current and filtering out the high-frequency harmonic components in the pulsating current so as to drive the string of LEDs. The control unit is coupled to the flyback PFC converter and the harmonics-filtering unit, for producing the PWM signal according to the AC power and the pulsating current, and reducing the peak-to-average ratio (PAR) of the pulsating current.

Driving apparatus for light emitting diodes without employing electrolytic capacitor

A power factor correction (PFC) circuit includes an inductor, a diode, a storage capacitor, a switch and a control unit. The input power has a voltage fluctuation V. The storage component absorbs a first voltage fluctuation and a switch regulation circuit absorbs a second voltage fluctuation V. Thus output voltage from the PFC circuit is not a conventional constant voltage but a voltage of a great ripple. The PFC circuit further has a harmonic regulation unit. The harmonic regulation unit generates a voltage signal containing 3harmonic. The control unit receives a feedback signal and the voltage signal containing 3harmonic to generate a reference to the inductor current. Therefore, the inductor current contains 3harmonic. Thus power fluctuation absorbed and released by the capacitor is smaller. As a result energy storage capacitance can be reduced significantly.

Growing community of inventors

Nanjing, China

Xinbo Ruan