High performance adaptive switched LED driver

摘要

An LED driver controls current through an LED string. The LED driver generates a boosted PWM signal to drive a PWM transistor in the LED current path such that the PWM transistor maintains a substantially constant V_GS, thus minimizing turn-on impedance of the PWM transistor. A current mirror circuit controls peak LED current when the PWM transistor is on. A trimming circuit includes a set of programmable switches to couple or decouple trimming transistor from the LED current path, and allowing for fine calibration of the LED current. By maintaining a low resistance and compensating for current mismatch in the LED current path, the LED driver provides efficient power performance and robustness that is particularly beneficial in high current applications.