Patent ID: 8362832

Claim:
A three-level pulse width modulation (PWM) amplifier comprising: a prescaling unit including: a signal separator configured to separate an input signal into a first separated input signal and a second separated input signal based on a reference level, the first separated input signal only having levels equal to or higher than the reference level, the second separated input signal having levels lower than the reference level; and a scaler configured to multiply the first separated input signal by a first gain value to provide the scaled first separated input signal to a PWM generator; the PWM generator, wherein the PWM generator is configured to generate a three-level PWM signal having a first level, a second level and the reference level by varying based on the scaled first separated input signal the width of pulses having the first level and by varying based on the second separated input signal the width of pulses having the second level; and an output stage configured to drive an output node to the level of a first power supply voltage, of a second power supply voltage or of a third power supply voltage based on the three-level PWM signal.