Abstracto

A LED Driver Design based on Fly-back Convert without Auxiliary winding

Pengcheng Xu ，Zhigang Han.

For boosting and taking advantage of itsmany outstanding advantages, LED needsespecially designed power supplies driver. Based on fly-back convert topology, a LED driver design is proposed but without auxiliary winding. According to the fly-back ampere-turns ratio conservation, the peak current through secondary side can be specified. The ratio of the interval time of secondary side flowing current to the switching period can also be set under performance of Zero Cross Detection schematic. In the role of filter and charge conservation, the output drive current will be constant. A more stable operation condition can be controlled by limiting the maximum and minimum interval time of secondary side flowing current. The elaborate adjust circuit in ZCD can magnify the resonance signal for better catching ring signal. Simulation results meet the schematic theoretical analysis and design specification.