HIGH PERFORMANCE ADAPTIVE SWITCHED LED DRIVER

摘要

The LED driver controls the current through the LED string. The LED driver generates a boosted PWM signal to drive the PWM transistor in the LED current path so that the PWM transistor maintains a substantially constant V _GS and thus the turn on impedance of the PWM transistor, on impedance. When the PWM transistor is on, the current mirror circuit controls the peak LED current. The trimming circuit includes a set of proramable switches that couple or decouples a trimming transistor from the LED current path and provides a precise calibration of the LED current (fine calibration). By compensating for current mismatch in the LED current path and maintaining a low resistance, the LED driver is able to provide robustness and efficient power performance that are particularly useful for high current applications to provide.