Frequency dependent loss analysis and minimization of system losses in switch-mode audio power amplifiers

摘要

In this paper, frequency dependent losses in switch-mode audio power amplifiers are analyzed and a loss model is improved by taking the voltage dependence of the parasitic capacitance of MOSFETs into account. The estimated power losses are compared to the measurement and great accuracy is achieved. By choosing the optimal switching frequency based on the proposed analysis, the experimental results show that system power losses of the reference design are minimized and an efficiency improvement of 8 % in maximum is achieved without compromising audio performances.