Patent ID: 6388514
Filing Date: 2002-05-14
Classification: H03F

Abstract:
A system for amplifying an input signal, comprising:level-shift PWM circuitry for level-shifting and converting the input signal into a pulse width modulated signal; gate drive circuitry for receiving the level-shifted pulse width modulated input signal and converting the signal into gate drive signals for controlling upper and lower transistor switches arranged in a half-bridge configuration to alternatively switch a positive and negative voltage applied thereto, thereby generating an output signal having a switching frequency; adaptive power supply control circuitry for adjusting the magnitude of the positive and negative voltage switched by the upper and lower transistor switches in the half-bridge arrangement in accordance with the magnitude of the input signal, such that when the input signal is absent, the positive and negative voltage switched is reduced to a low level to reduce switching losses and, when the input signal increases, the positive and negative voltage switched is increased by an amount proportional to the input signal level; and filter circuitry for removing the switching frequency from the output signal to generate an amplified system output signal to be applied to a load.