Shahid Rajaee Teacher Training University Journal of Electrical and Computer Engineering Innovations (JECEI) 2322-3952 2 1 2014 01 01 THD Analysis in Closed-Loop Analog PWM Class-D Amplifiers 1 5 36 10.22061/jecei.2014.36 EN P. Amiri Faculty of Electrical and Computer Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran. M. Kohestani Faculty of Electrical and Computer Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran. M. Seifouri Faculty of Electrical and Computer Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran. Journal Article 2014 02 10 In this paper, we investigate the parameters affecting Total Harmonic Distortion (THD) and Power Supply Rejection Ratio (PSRR) in PWM Class D Amplifiers (CDAs) 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 the integrator. We also show that the THD can be further improved by means of two cascaded amplifiers with a single pole. We verify our analysis by means of PSPICE simulations. Simulation results show that the THD of the gain boosting and the two cascaded amplifiers with a single pole CDAs can be improved by as much as 1.4 times and 2 times, respectively. https://jecei.sru.ac.ir/article_36_470360c97099dbf8f5e9b8e03c9db0e4.pdf