Audio amplifier with high pass filter based distortion suppression

An audio amplifier, comprising:

• a loop filter, comprising multiple amplifiers, and arranged to receive an audio signal and a feedback signal, wherein the multiple amplifiers comprise:
• a first amplifier, having a first output node, and arranged to process the audio signal and the feedback signal;
• and
• a second amplifier, having a first input node arranged to receive a first amplifier input and a second amplifier input, wherein the first amplifier input is obtained from a first signal path coupled between the first output node and the first input node;
• at least one high pass filter (HPF) circuit, coupled between the first amplifier and the second amplifier, and arranged to receive an amplifier output of the first amplifier, and generate and output the second amplifier input according to the amplifier output of the first amplifier;
• a pulse width modulation (PWM) generator, arranged to generate a PWM signal according to an amplifier output of the second amplifier;
• and
• a power stage, arranged to drive a load according to the PWM signal;
• wherein an output terminal of the power stage is coupled to an input terminal of the loop filter to form a feedback path, and the feedback signal is transmitted from the output terminal of the power stage to the input terminal of the loop filter through the feedback path;
• wherein the second amplifier input is a high-pass filtered result of an inversion version of the first amplifier input, and the first amplifier input and the second amplifier input is added at the first input node of the second amplifier for reducing a high frequency component of the first amplifier input.