Abstract: The present invention relates to a full bridge class-D amplifier where one of the output terminals (27) is grounded, and which is arranged to be supplied by a floating power supply (1). Each amplifier switching leg (7, 15) is connected to the corresponding load terminal (25, 27) via a low-pass filter (29, 31), at least one of which comprises a capacitor (C1, C2, C3 or C4), connected between the load terminal and the positive or negative output terminal (3, 5) of the floating power supply.

Abstract: A switch mode power supply for feeding a single ended class D amplifier, having. two voltage sources (1, 2) is disclosed. The power supply comprises a voltage equalizer circuit including a coil (10) having a first terminal connected to said common point (3), a first switch (11) connected between a second terminal of the coil (10) and the positive side of the first source (1), a second switch (12) connected between said second terminal of the coil (1) and the negative side of the second source (2), and control circuitry (13, 14) for determining when the voltage (v 1, v2) of one of the voltage sources (1 or 2) exceeds a predetermined threshold value (vthresh,ON), and, in response to such a determination, periodically operate the switch (11 or 12) associated with said one voltage source ON and OFF, thereby redistributing energy from said one voltage source (1 or 2) to the other voltage source (2 or 1).