We investigate the influence of two important practical design parameters on total harmonic distortion (THD) for the design of low-voltage (0.9-1.4 V) low-power analog Class-D amplifiers: the linearity of the carrier waveform and the impedance of the output stage. We show that the carrier nonlinearity results in THD and propose a novel mathematical analysis method to model the nonlinearity. We recommend a range of the parameter that describes the carrier nonlinearity and that results in a good compromise to the dynamic range of the pulsewidth modulator of the Class-D amplifier. We show that the impedance of the output stage has little effect on THD. We verify our analyses by means of MATLAB and HSPICE computer simulations, and on the basis of practical measurements.
Published in:
Circuits and Systems I: Fundamental Theory and Applications, IEEE Transactions on
(Volume:50
,
Issue:
10
)
Date of Publication: Oct. 2003