Patent ID: 8760081

Claim:
An LCD backlight circuit, the LCD backlight circuit comprising: a lamp; an analog inverter circuit that provides a drive voltage to the lamp based at least in part on a pulse width modulated (PWM) signal; a current sensor that is coupled to the lamp so as to sense a current traversing the lamp; and a digital control circuit that is coupled to the current sensor, wherein the digital control circuit compares the sensed current to a threshold current, and wherein the digital control circuit increases the duty cycle of the PMW signal if the sensed current is less than the threshold current so as to increase the drive voltage, wherein the digital control circuit is a digital signal processor, wherein the analog inverter is a class-D inverter, and wherein the control signal is designed to induce a pre-distorted sinusoidal voltage on the drive voltage, wherein the pre-distorted sinusoidal voltage is designed to result in a substantially pure sinusoidal current traversing the lamp.