thd analysis in closed-loop analog PWM class-D amplifiers

in this paper we investigate the parameters affecting total harmonic distortion and power supply rejection ratio in PWM class D amplifiers on the basis of linear models with feedback.from our mathematical analysis we show that the THD of a PWM class D amplifier with feedback can be improved by increasing the gain of the integrator through adding another amplifier at the output of integrator.we also show taht the THD can be further improved by means of two cascaded amplifiers.simulation results show that the THD of the gain boosting and the two cascaded amplifiers with a singel pole CDAscan be improved by as much as 1.4 times and 2 times respectively.