Avoid Overvoltage Stresses by Minimizing Power-Supply Pumping on Single-Ended Output, Class D Audio Amplifiers

Abstract: This application note explains what power-supply pumping is and how it occurs in designs that employ a Class D audio amplifier with single-ended output loads. The article presents three design solutions that will reduce the problem. Mathematical equations show that use of power-supply capacitors greater than 1000µF greatly reduce the phenomenon. The MAX9742 Class D amplifier serves as design example.