Texas Instruments Incorporated
MAXIMUM POWER DETECTION AND AUTOMATIC GAIN CONTROL FOR CAPACITIVE CLASS-D AMPLIFIERS

Abstract:

A system includes a charge pump having an input coupled to a first voltage and an output at a second voltage, the second voltage greater than the first voltage. The system also includes an amplifier having a first input, a second input, and a third input, the first input coupled to the output of the charge pump, the second input coupled to the first voltage, the third input coupled to an input signal, the amplifier having an amplified output signal. The system also includes a maximum power detector coupled to the amplifier, the maximum power detector operable to determine whether the amplified output signal has reached a threshold output level and to reduce a power of the amplified output signal responsive to the determination.