Experimental verification of cooperative control method for 400-W class LED driver with wide dimming range

This paper proposes a new cooperative-control strategy for a 400-W class light-emitting diode (LED) driver consisting of two DC/DC converters operating in the discontinuous current mode (DCM). In the cooperative control method, one DC/DC converter is selected to supply the output current for the LED, based on the reference value of the LED current. Thus, the proposed cooperative-control strategy achieves wide dimming range operation. The DCM operation improves the total harmonic distortion (THD) value at the ac side of the LED driver. The basic principle of the proposed control strategy is discussed, and is then confirmed by digital computer simulations. A prototype LED driver is constructed and tested. Experimental results demonstrate that a wide dimming operation range from 1% to 100% is achieved with a THD value less than 10% at the ac side, by the proposed control strategy.