Shorting-inductor approach for dimming high power light-emitting diodes

Parallel dimming for reducing the intensity of high power light-emitting diode (HP-LED) is an effective way of achieving high contrast ratio and wide dimming range. However the scheme has limitation due to response of control loop and higher power dissipation due to losses during turn-off period. Therefore shorting-inductor approach is proposed in this paper which is capable of achieving improvement in efficiency while keeping similar level of performance. Moreover the proposed strategy for dimming HP-LED is considered to be more flexible in its design. For example the converter can provide dimming feature even if controller is not used to keep track of inductor current. This indicates performance of the method is assured with different types of control strategy which implies wider deployment in different applications.