Patent ID: 7667444
Filing Date: 2010-02-23
Classification: H03F

Abstract:
1. A method of driving a capacitive load, comprising the steps of: providing an analog input signal; in a generating step, generating a pulse-width modulated (PWM) waveform, wherein said generating step includes comparing said analog input signal with a specified modulation waveform, thereby modulating and discretizing said analog input signal, the specified modulation waveform comprising a series of approximately parabolic waveforms; processing said PWM waveform to generate a discrete low-harmonic sine wave approximation; producing a plurality of drive signals from said discrete low-harmonic sine wave approximation; applying said plurality of drive signals to a plurality of switches, respectively, said plurality of switches being coupleable to said capacitive load; and in response to applying said plurality of drive signals to said plurality of switches, respectively, driving said capacitive load by switchingly connecting said capacitive load between a source output and a reference potential to charge said capacitive load positively, and to discharge said capacitive load or charge said capacitive load negatively.