LED driver with a combined energy transfer inductor for current balancing

A two-channel LED backlight driver for LCD monitor application using an integrated magnetic component, which is a combined energy transfer inductor for current balancing, is proposed in this paper. The integrated magnetic component has two functions: boost inductor and differential-mode current balance transformer. With proper design and arrangement, all 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. Compared with conventional topology, not only the power density is increased but the overall cost and volume of the magnetic component is also further reduced. The operating principles and design considerations of the proposed LED driver are analyzed. A 10-W prototype converter with two-channel LED string was developed to verify the feasibility of the proposed driver. Experimental results show that the proposed LED driver approach can provide an equally significant two-channel LED string current.