Switching audio amplifier with improved voltage supply control

A method for controlling a switching audio amplifier, the method comprising:

• coupling, by a voltage supply selector, a power supply input to a first power supply voltage of a plurality of power supply voltages;
• generating, by a switching circuit, a drive signal for driving a loudspeaker by modulating the power supply input based on a modulation signal;
• receiving, by a pulse generator, an audio input signal;
• outputting, by the pulse generator, the modulation signal based on the audio input signal and the voltage of the power supply input such that the drive signal generated by the switching circuit corresponds to the audio input signal;
• determining, by a supply voltage monitor, whether the modulation signal exceeds a first threshold;
• causing, by the supply voltage monitor, responsive to determining that the modulation signal exceeds the first threshold, the voltage supply selector to increase the voltage of the power supply input by coupling the power supply input to a second power supply voltage of the plurality of power supply voltages;
• and
• preventing, by the supply voltage monitor, the voltage supply selector from reducing the voltage of the power supply input for a first time period.

A packaged module comprising:

• a packaging substrate;
• a switching audio amplifier implemented on the packaging substrate and comprising a voltage supply selector configured to couple a power supply input to a first power supply voltage of a plurality of power supply voltages;
• a switching circuit configured to generate a drive signal for driving a loudspeaker by modulating the power supply input based on a modulation signal;
• a pulse generator configured to receive an audio input signal and to output the modulation signal based on the audio input signal and the voltage of the power supply input such that the drive signal generated by the switching circuit corresponds to the audio input signal;
• and a supply voltage monitor configured to determine whether the modulation signal exceeds a first threshold, the supply voltage monitor being configured to increase the voltage of the power supply input by causing the voltage supply selector to couple the power supply input to a second power supply voltage of the plurality of power supply voltages responsive to determining that the modulation signal exceeds the first threshold, the supply voltage monitor being configured to prevent the voltage supply selector from reducing the voltage of the power supply input for a first time period.