Time interleaved analog to digital converter and gain calibration method

A gain calibration method, comprising:

• sampling an input signal according to a plurality of first clock signals to generate a plurality of first signals;
• amplifying, by a plurality of amplifier circuits, the plurality of first signals to generate a plurality of second signals;
• performing a plurality of analog-to-digital conversions according to the plurality of second signals to generate a plurality of digital signals;
• and
• adjusting a delay time of each of the plurality of first clock signals and calibrating gains of the plurality of amplifier circuits according to the plurality of digital signals,
• wherein adjusting the delay time of each of the plurality of first clock signals and calibrating the gains of the plurality of amplifier circuits according to the plurality of digital signals comprises:
• outputting, by a flip-flop circuit, a third signal as a count signal according to a second clock signal;
• adding, by a first adder circuit, the count signal and a predetermined value to generate the third signal;
• and
• multiplying, by a multiplier circuit, the third signal and a delay signal to generate a fourth signal, wherein the fourth signal is configured to indicate an adjustment amount of the delay time;
• and
• adding, by a plurality of second adder circuits, the fourth signal to the plurality of first clock signals respectively, in order to adjust the plurality of first clock signals.