Variable frequency self-oscillating converter applied as a LED driver

Abstract

A drive converter for light emitting diodes (LEDs) is presented. The driver is based on a half-bridge self-oscillating converter (SOC) and uses variable frequency to reduce the output current fluctuation due to the input voltage ripple coming from a previous power factor corrector (PFC) stage. The proposal prototype employs a discrete self-oscillating drive circuit with a series resonant tank and a simple frequency control circuit. The topology uses no electrolytic capacitors and experimental results shows the feasibility of the proposal.