A novel multiple modes PWM controller for LEDs

Abstract

A monolithic controller for pulse width modulation (PWM) DC-DC converter was presented in this paper. The controller was designed specially for LED (light emitting diode) driver circuit with four operation modes, current feedback mode, constant current mode, no sense resistor mode and PWM dimming mode. The controller can be adapted to almost all current DC-DC topologies such like Boost, Buck-Boost and etc.. It also features the different load current sense methods for different topologies. For LED lighting, both the digital and analog dimming modules were integrated onto the chip, which were used to meet the demands of two kinds of dimming applications respectively. The controller integrated circuit (IC) was designed, simulated and fabricated in 1.5 mum BCD process. And both the simulation and test results were consistent with expectations well.