The ambient light adaptive LED driver automatically adjusts display brightness for changing ambient light conditions, providing a more viewable display with better contrast. The design shown here drives three series-connected LEDs from an input voltage of 4.5V to 5.5V, provides 100mA current, and outputs 10V to 15V. The heart of the design is Texas Instruments' PowerWise® LM3423 LED driver, which has all the features needed to implement a boost converter with output current regulation and pulse-width modulation (PWM) dimming of the current.