Hybrid class-D amplifier

An amplifier, comprising:

• a digital-to-analog conversion (DAC) input stage circuit, configured to convert a digital signal into an analog signal;
• a loop filter circuit, electrically coupled to the DAC input stage circuit, configured to generate a filtered signal according to the analog signal and a feedback signal;
• a quantizer circuit, electrically coupled to the loop filter circuit, configured to perform a quantization operation on the filtered signal to generate a quantized signal;
• an output stage circuit, electrically coupled to the quantizer circuit, configured to perform power amplification on the quantized signal to generate an output signal;
• and
• a feedback circuit, electrically coupled between the output stage circuit and the loop filter circuit, configured to generate the feedback signal according to the output signal;
• wherein the digital signal comprises a first digital signal of a first cycle and a second digital signal of a second cycle after the first cycle, and the DAC input stage circuit comprises:
• a first current source, electrically coupled to a first reference voltage;
• a second current source, electrically coupled to a second reference voltage;
• a first switch circuit, electrically coupled to the first current source, the second current source and an input terminal of the loop filter circuit, configured to control the input terminal of the loop filter circuit to be electrically coupled to one of the first current source and the second current source according to one of multiple bits of the first digital signal;
• a third current source, electrically coupled to the first reference voltage;
• a fourth current source, electrically coupled to the second reference voltage;
• and
• a second switch circuit, electrically coupled to the third current source, the fourth current source and the input terminal of the loop filter circuit, configured to control the input terminal of the loop filter circuit to be electrically coupled to one of the third current source and the fourth current source according to one of multiple bits of the second digital signal.