Class-D amplifier with duty cycle control

An integrated circuit, comprising:

• a class-D audio amplifier, comprising:
• an output driver comprising an H-bridge configured to drive a loudspeaker;
• a pulse width modulator configured to provide input to the output driver;
• an integrator configured to provide input to the pulse width modulator;
• and
• duty cycle control circuitry coupled to the integrator, the duty cycle control circuitry comprising:
• thresholding circuitry comprising:
• a first comparator coupled an output of the integrator, the first comparator is configured to compare amplitude of signal output by the integrator to a first threshold value;
• and
• a second comparator is coupled the output of the integrator, the second comparator is configured to compare the amplitude to a second threshold value;
• wherein the first threshold is higher than the second threshold;
• a comparing circuit coupled to the thresholding circuitry and configured to determine, based on outputs of the first comparator and the second comparator, whether an average duty cycle of signal at an output of the output driver is to be changed;
• duty cycle adjustment circuitry coupled to the comparing circuit and configured to change the average duty cycle based on an output of the comparing circuit;
• wherein the average duty cycle is an average of a duty cycle of signal produced at a first loudspeaker drive terminal of the H-bridge and a signal produced at a second loudspeaker drive terminal of the H-bridge.