A built-in self-test high-current LED driver

In this paper, a built-in self-test (BIST) high-current light-emitting-diode (LED) driver circuit is proposed. The circuit not only maintains different constant currents for multiple LED strings, but it also minimizes the conduction power dissipation by keeping the power MOSFETs in the constant-current controllers operating in the linear region. The proposed driver first acquires the current-voltage (I-V) data of the constant-current power MOSFETs and stores them into memories. These stored I-V data, along with a duty cycle control of the switching converter, are used to ensure that these power MOSFETs are operating in their linear region to minimize conduction power dissipation. The proposed circuit was verified using PSPICE with two to five LED strings. Simulation results show a maximum efficiency of 95.6%.