Abstract: The present invention discloses an AC impedance measurement circuit with a calibration function, which is characterized in that only one calibration impedance is needed, associated with a switch circuit. Based on the measurement results of the two calibration modes, an equivalent impedance of the switch circuit, circuit gain and phase offset can be calculated. Based on the above results, the equivalent impedance of the internal circuit is deducted from the measurement result of the measurement mode to accurately calculate an AC conductance and a phase of the AC conductance for impedance to be measured. In addition, by adjusting a phase difference between an input sine wave signal and a sampling clock signal, impedance of the same phase and impedance of the quadrature phase can be obtained, respectively, and the AC impedance and phase angle of the impedance to be measured can be calculated.

Abstract: The present invention discloses an AC impedance measurement circuit with a calibration function, which is characterized in that only one calibration impedance is needed, associated with a switch circuit. Based on the measurement results of the two calibration modes, an equivalent impedance of the switch circuit, circuit gain and phase offset can be calculated. Based on the above results, the equivalent impedance of the internal circuit is deducted from the measurement result of the measurement mode to accurately calculate an AC conductance and a phase of the AC conductance for impedance to be measured. In addition, by adjusting a phase difference between an input sine wave signal and a sampling clock signal, impedance of the same phase and impedance of the quadrature phase can be obtained, respectively, and the AC impedance and phase angle of the impedance to be measured can be calculated.