Switching Audio Power Amplifier

This example shows a switching audio power amplifier circuit. Switching audio power amplifiers are more efficient than conventional power amplifiers as switching devices are operating only in the fully-on and fully-off states. This audio power amplifier uses a 1MHz switching frequency and has a PI feedback controller to ensure that output voltage tracks the 2kHz and 2.5kHz sine wave inputs. The power spectrum is plotted in the Spectrum Analyzer, and can be used to inform selection of controller and filter parameters.

Model

Simulation Results from Simscape Logging

The plot below shows the output voltage as compared to the reference voltage. It also shows the dissipated power of the two MOSFETS averaged over 100 PWM cycles.

Simulation Results from Scopes

The power spectrum plotted in the Spectrum Analyzer shows peaks at 2kHz and 2.5kHz, the two components of the reference voltage.