A Novel Driver Circuit for Supplying LED Projection Lamps with High-Power-Factor and Soft-Switching

This paper presents a novel single-stage AC-DC drive circuit for powering LED projection lamps, which combines a modified stacked boost converter with a half-bridge LLC resonant converter into a single-stage power converter with power-factor correction (PFC) and soft switching. The PFC functionality is realized by designing the inductor in the modified stacked boost converter subcircuit in discontinuous-conduction-mode (DCM). Besides, the power switch features zero-voltage switching (ZVS), which reduces switching losses and improves the efficiency of the proposed driver circuit.This paper has completed the development of a 100W (36V/2.77A) prototype driver circuit, and tested the experimental results when the input mains line voltage is 110 V. According to the test results of the single-stage AC-DC driver circuit, the power factor is greater than 0.99, the total harmonic distortion factor of the input current is less than 6%, and the circuit efficiency is greater than 89%. Therefore, satisfactory experimental results demonstrate the functionality of the proposed driver circuit for powering the LED projection lamp.