Charge-steering amplifier circuit and control method thereof

A control method of a charge-steering amplifier circuit which comprises a charge-steering amplifier and a sample-and-hold circuit, the charge-steering amplifier circuit operating in a reset phase or an amplification phase, the charge-steering amplifier performing an amplification operation on a first sampled signal and a second sampled signal in the amplification phase, the method comprising:

• obtaining a common-mode voltage of a differential input signal in the reset phase;
• providing the common-mode voltage and a direct current (DC) voltage to an output terminal of the charge-steering amplifier in the reset phase;
• using the sample-and-hold circuit to sample the differential input signal to generate the first sampled signal and the second sampled signal in the reset phase;
• and
• inputting the first sampled signal and the second sampled signal to the charge-steering amplifier in the amplification phase.

A charge-steering amplifier circuit for amplifying a differential input signal, comprising:

• a sample-and-hold circuit configured to sample the differential input signal to generate a first sampled signal and a second sampled signal;
• a charge-steering amplifier coupled to the sample-and-hold circuit and comprising:
• a first input terminal configured to receive the first sampled signal;
• a second input terminal configured to receive the second sampled signal;
• a first output terminal;
• a second output terminal;
• a first switch;
• a second switch;
• a third switch;
• a fourth switch;
• a first load capacitor having a first end and a second end, wherein the first end is coupled to the first output terminal through the first switch and coupled to a first reference voltage through the second switch;
• and
• a second load capacitor having a third end and a fourth end, wherein the third end is coupled to the second output terminal through the third switch and coupled to the first reference voltage through the fourth switch;
• a common-mode voltage generation circuit configured to generate a common-mode voltage of the differential input signal according to the differential input signal;
• and
• a switch circuit coupled to the charge-steering amplifier and the common-mode voltage generation circuit and configured to couple the second end and the fourth end to the common-mode voltage or a second reference voltage.