A dual-feedforward carrier-modulated second-order class-D amplifier with improved THD
Tan, Meng Tong
Goh, Wang Ling
Cox, Stephen Michael
Date of Issue2011
School of Electrical and Electronic Engineering
The advancement of power MOSFET fabrication technology has aided the reduction of power stage errors in class-D amplifiers (amps). This reduction reveals intrinsic distortion, which is a key performance limiter in modern pulsewidth-modulation (PWM)-based class-D amps. In this brief, a dual-feedforward carrier modulation topology is proposed to reduce the intrinsic harmonic distortion of a second-order loop filter class-D amp. The proposed design achieves a total harmonic distortion of less than 0.01% for input frequency up to 6 kHz, and it has an idle carrier frequency of 310 kHz. Such low carrier frequency is particularly important in high-power devices as it guarantees low switching loss. Moreover, the carrier frequency varies in a narrow range in the presence of an input signal and helps to suppress the audible intermodulation distortion in multichannel applications. The prototype circuit is implemented and tested on a printed circuit board using discrete components.
DRNTU::Engineering::Electrical and electronic engineering
IEEE transactions on circuits and systems II : express briefs
© 2011 IEEE.