Self-calibration digital-to-analog converter and calibration method thereof

A self-calibration digital-to-analog conversion circuit, comprising:

• a resistor circuit, comprising a plurality of bit input terminals, a reference voltage input terminal, an output terminal and a common connection correction terminal, wherein the reference voltage input terminal of the resistor circuit receives a reference voltage;
• a buffer amplifier, comprising a first input terminal, a second terminal and an output terminal;
• a fine-tuning circuit, comprising a first input terminal, a second terminal and an output terminal, wherein the first input terminal of the fine-tuning circuit is coupled to the output terminal of the resistor circuit, the output terminal of the fine-tuning circuit is coupled to the first input terminal of the buffer amplifier, the second input terminal of the fine-tuning circuit is coupled to the output terminal of the buffer amplifier;
• and
• a correction switching circuit, comprising a first terminal and a second terminal, wherein the first terminal of the correction switch circuit is coupled to the second input terminal of the buffer amplifier, the second terminal of the correction switching circuit is coupled to the output terminal of the buffer amplifier,
• wherein, in the self-calibration digital-to-analog conversion circuit, under a normal operation mode, the common connection correction terminal of the resistor circuit is input a common connection voltage, and the first terminal and the second terminal of the correction switching circuit are short-circuited;
• wherein the self-calibration digital-to-analog conversion circuit, under a correction mode, comprises:
• a sampling time:
• the first terminal and the second terminal of the correction switching circuit are short-circuited, wherein the common connection correction terminal of the resistor circuit is input the reference voltage, the plurality of bit input terminals of the resistor circuit are input first correction data, and the first terminal of the correction switching circuit samples a voltage at the second input terminal of the buffer amplifier and stores the voltage;
• and
• a comparison time:
• the common connection correction terminal of the resistor terminal is input a common connection voltage, the plurality of bit input terminals of the resistor circuit are input second correction data, the first terminal and the second terminal of the correction switching circuit are open-circuited, and the voltage sampled at the first terminal of the correction switching circuit is output to the second input terminal of the buffer amplifier,
• wherein, during the comparison time, the fine-tuning circuit adjusts correction data and adjusts the voltage at the output terminal of the fine-tuning circuit according to the correction data until a voltage at the output terminal of the buffer amplifier switches from a first saturation voltage to a second saturation voltage,
• wherein the fine-tuning circuit records the correction data when the voltage at the output terminal of the buffer amplifier switches from the first saturation voltage to the second saturation voltage as the correction data corresponding to the second correction data,
• wherein, when the common connection correction terminal of the resistor circuit is input the reference voltage and the resistor circuit is input the first correction data, an ideal voltage at the output terminal of the resistor circuit is a first theoretical voltage,
• wherein, when the common connection correction terminal of the resistor circuit is input the common connection voltage and the resistor circuit is input the second correction data, an ideal voltage at the output terminal of the resistor circuit is a second theoretical voltage, and
• wherein the first theoretical voltage equals to the second theoretical voltage.