Design and analysis for backlight inverter with four-phase PWM dimming control

This paper proposes a novel control scheme which possesses four-phase PWM dimming control for backlight inverter with triple output lamp currents for each phase. We adopt four-phase PWM dimming control circuit to control the brightness of twelve lamps. Each phase driving circuit can control three lamp currents. Circuit architecture is full bridge phase-shift circuit which can improve the total efficiency of the driving circuit. Four-phase PWM dimming possesses smaller error range E(%) of lamp currents comparing with single-phase PWM dimming. It is also better than single phase PWM dimming in power efficiency η for inverters. From the experimental results, we verify the performance that four-phase PWM dimming will be better than the conventional single phase one.