Title :
A Low-THD Class-D Audio Amplifier With Dual-Level Dual-Phase Carrier Pulsewidth Modulation
Author :
Shang-Hsien Yang ; Yuan-Han Yang ; Ke-Horng Chen ; Ying-Hsi Lin ; Tsung-Yen Tsai ; Shian-Ru Lin ; Chao-Cheng Lee
Author_Institution :
Inst. of Electr. & Comput. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Abstract :
In this paper, a class-D audio amplifier which combines the advantages of the phase-shifted carrier pulsewidth modulation (PWM) and the multiple-level carrier PWM is proposed with a dual-level dual-phase carrier (DLDPC) PWM. The proposed closed-loop amplifier includes a second-order integrator and a DLDPC triangular wave generator. Two sets of 180° out-of-phase triangular waves are used as carriers, and each set has its respective offset voltage level with nonoverlapping amplitude. By performing the double Fourier analysis, it can be found that the linearity can be enhanced and the distortion can be reduced with the proposed modulation. Experimental results show that the proposed fully differential DLDPC PWM class-D audio amplifier features a total harmonic distortion lower than 0.01% with an output voltage swing of ±5 V.
Keywords :
Fourier analysis; PWM invertors; audio-frequency amplifiers; harmonic distortion; integrating circuits; phase shifters; waveform generators; DLDPC triangular wave generator; closed-loop amplifier; double Fourier analysis; dual-level dual-phase carrier pulsewidth modulation; fully differential DLDPC PWM class-D audio amplifier; low-THD class-D audio amplifier; nonoverlapping amplitude; offset voltage level; out-of-phase triangular waves; second-order integrator; total harmonic distortion reduction; Generators; Harmonic analysis; Power harmonic filters; Pulse width modulation; Regulators; Switches; Class-D; DLDPC; IMD; MLCPWM; PSCPWM; PWM; THD; dual-level dual-phase carrier; dual-level dual-phase carrier (DLDPC); dual-level dual-phase carrier (DLDPC) PWM; intermodulation (IMD); multilevel carrier pulsewidth modulation (MLCPWM); phase-shifted carrier pulsewidth modulation (PSCPWM); total harmonic distortion (THD);
Journal_Title :
Industrial Electronics, IEEE Transactions on
DOI :
10.1109/TIE.2015.2448518