US Patent 10075178 Digital-to-analog converter and an operation method thereof

A digital-to-analog converter (DAC) includes a DAC circuit, a switch circuit and a control circuit. The DAC circuit includes most significant bit digital-to-analog converter (MDAC) circuits and calibration digital-to-analog converter (CDAC) circuits. The switch circuit includes a current source circuit and a detection circuit. The MDAC, CDAC circuits and the current source circuit are coupled to a first output terminal and a second output terminal of the DAC circuit. In a calibration mode, the current source circuit generates current deviation of the first output terminal and the second output terminal. The detection circuit detects the current differences to generate detection signals. The control circuit outputs control signals to the CDAC circuits to adjust output currents of the CDACs at the first output terminal and the second output terminal. In a regular mode, the current source circuit is configured to function as a dual DC current source.