Light-emitting diode driver with a combined energy transfer inductor for current balancing control

This study proposes a two-channel light-emitting diode (LED) backlight driver specifically for liquid crystal display monitor application that utilises an integrated magnetic component: a combined energy transfer inductor for current balancing. The integrated magnetic component has two functions: as a boost inductor and as a differential-mode current balance transformer. Under proper design and arrangement, all of the windings are wound on a single UU-core. This scheme uses leakage inductance as boost inductor for energy transfer and mutual inductance as differential mode transformer for output current balancing. By introducing the magnetic component, power density is increased whereas the overall cost and volume of the magnetic components are reduced in comparison with those values under conventional topology. The operating principles and design considerations of the proposed LED driver were analysed. A 10 W prototype converter with a two-channel LED string was developed to verify the feasibility of the proposed driver. Experimental results show that the proposed LED driver provides an equal current for a two-channel LED string.