93% Efficiency and 0.99 power factor in pseudo-linear LED driver

The proposed pseudo-linear LED driver can effectively solve the serious flicker in conventional linear LED driver (LLD). Besides, it has good electromagnetic interference (EMI) performance similar to that in conventional LLD at high AC input voltage. In the meanwhile, it has high power factor (PF) similar to boost switching regulator (SWR) LED driver at low AC input voltage. Furthermore, owing to the combination of line filter and the active full bridge rectifier, the pseudo-linear LED driver has a compact solution and high efficiency. The test chip was fabricated in 0.5μm 500V LDMOS process. Experimental results show 93% high efficiency, 6% total harmonic distortion (THD), and 0.99 PF at the power of 7W.