Abstract:
In a switched-power amplifier that has controlled power supply rails, e.g., when a volume control is implemented by varying the power supply voltages, a rate-controlled power supply control circuit eliminates audible pops that would otherwise occur when a change in input level causes the power supply rail voltages to change. The control circuit generates control signals that control the regulators providing the power supply rails with a controlled rate of change such that asymmetry between the voltages of the power supply rail outputs during changes of the power supply rails is substantially reduced. The controlled rate of change is less than or equal to the slowest rate of change of the power supply outputs that supply the power supply rails of the switched-power amplifier.