Soft-switched full-bridge converter for LED lighting applications with reduced switch current

Lighting systems using light-emitting diode (LED) have drawn significant attention across the world. This is due to their promising features such as high energy efficiency, reduced greenhouse gas emission, and eco-friendly nature. However, these systems require constant current regulators to provide constant illumination. This article proposes a soft-switched full-bridge LED driver circuit for dc-grid applications with dimming control operation. The circuit consists of a soft-switched full-bridge converter to power different LED lamps with reduced device count from dc-grid voltage. The semiconductor switches of the full-bridge converter conduct a small current during on time due to interleaved inductor and equal current sharing of lamp-2 and lamp-3. This feature reduces the conduction losses. In addition, the proposed converter yields less component count per lamp, dimming operation through on-off control and zero voltage switching, which results in low switching losses. The detailed steady-state analysis of the proposed converter for dc-grid applications with dimming control operation is presented in this work. The performance of the proposed converter is compared with other similar topologies available in the recent literature. Numerical simulations and real-time experimental validations are conducted to evaluate the steady-state performance of the proposed converter topology for LED applications, driving multiple lamp loads from dc-grid. It has been established that the efficiency of the proposed full-bridge converter is 97.52% at the rated power.