High-efficiency amplifier architecture with de-gain stage

An amplifier, comprising:

• an input stage, configured to receive an input signal to generate an amplified signal;
• an amplifier stage, coupled to the input stage, configured to generate a first driving signal and a second driving signal according to the amplified signal;
• a power stage comprising a first input terminal and a second input terminal, wherein the power stage is coupled to a supply voltage and a ground voltage, for receiving the first driving signal and the second driving signal from the first input terminal and the second input terminal, respectively, and generating an output signal;
• and
• a de-gain stage, coupled to the power stage, configured to generate a first control signal to the first input terminal according to the second driving signal;
• wherein the de-gain stage comprises:
• a first low-pass filter, configured to filter the second driving signal to generate a filtered second driving signal;
• and
• a first control circuit, coupled to the first low-pass filter, configured to generate the first control signal to the first input terminal of the power stage to limit a swing of the first driving signal according to the filtered second driving signal.