LAUSR

Switch-mode technology is the common choice for high-efficiency audio power amplifiers. The dynamic nature of real audio limits the achievable continuous output power thus reducing efficiency. Based on methods used for radio frequency (RF) amplifiers, this article proposes a tracking multilevel power supply (TMLPS) in order to improve system efficiency. A simple prototype is designed and tested up to 200 W. Measured results show that employing a TMLPS can improve efficiency with a factor of 6 when playing music. In addition, the temperature rise of the amplifier is vastly reduced, especially for the switching power MOSFETs where it is halved from 100 °C to 50 °C. To further improve efficiency, an optimization method is proposed. The optimization considers the amplitude distribution of music signals and consumer behaviors. Simulations show that efficiency can be further improved by a factor of 1.23 with an optimized TMLPS compared to a simple uniform TMLPS solution.