A High-Power LED Driver Based on Single Inductor-Multiple Output DC–DC Converter With High Dimming Frequency and Wide Dimming Range

Abstract

This article proposes an LED driver circuit which is wide-range continuous dimmable for high power lighting application. The proposed LED driver is based on single-inductor–multiple-output (SIMO) dc–dc converter. A pulsewidth modulation (PWM) control strategy is applied on the LED driver to control the brightness of LEDs flexibly and precisely, with which the dimming frequency can be increased significantly, and the dimming ratio for all branches can be adjusted separately. PWM dimming would cause the inductor current overshooting when dimming switch alters from off to on , which makes the LED current varying. To suppress the inductor current overshooting, a sampling–holding circuit is adopted in the feedback loop of the proposed LED driver. A prototype of the proposed LED driver is fabricated and tested. The measurement results show that the dimming frequency can be increased to 10 kHz, the dimming ratio can be set from 5% to 100% with a minimum pulsewidth of 5 $\mu$ s, and the inductor current overshooting is suppressed from 150% to approximately 0%. The proposed LED driver can output more than 80 W and achieve a conversion efficiency of 97%.