Capacitance detection method and circuit

A capacitance detection circuit, comprising:

• a control module, a driving module, an offsetting module, a charge transfer module, and a processing module;
• N first offsetting processes and M second offsetting processes constituting a detection period during detection, wherein N, M≥1;
• the control module is configured to control the driving module, the offsetting module, and the charge transfer module performing charging, base capacitance offsetting, and charge transferring successively on a capacitor to be detected in an i-th first offsetting process of the first offsetting processes, respectively, to generate a first output voltage, wherein i≤N;
• the control module is configured to control the driving module, the offsetting module, and the charge transfer module performing discharging, base capacitance offsetting, and charge transferring on the capacitor to be detected successively in a j-th second offsetting process of the second offsetting processes, respectively, to generate a second output voltage, wherein j≤M;
• and
• the processing module is configured to determine a capacitance variation of the capacitor to be detected before and after the capacitor to be detected is affected by an external electric field based on the first output voltages corresponding to the N first offsetting processes and the second output voltages corresponding to the M second offsetting processes in the detection period, wherein:
• the offsetting module comprises an offset capacitor, and the control module is further configured to control the offset capacitor to perform a plurality of times of first offsetting operations on the capacitor to be detected until charges corresponding the base capacitance of the capacitor to be detected are offset in the i-th first offsetting process, each of the plurality of times of first offsetting operations comprising:
• charging an offset capacitor to a voltage of a voltage source Vcc minus a voltage source Vss;
• and performing charge offsetting on the capacitor to be detected through the charged offset capacitor;
• and
• the control module is further configured to control the offset capacitor to perform a plurality of times of second offsetting operations on the capacitor to be detected until the charges corresponding the base capacitance of the capacitor to be detected are offset in the j-th second offsetting process, each of the plurality of times of second offsetting operations comprising:
• charging an offset capacitor to a voltage of a voltage source Vss minus a voltage source Vcc;
• and performing charge offsetting on the capacitor to be detected through the charged offset capacitor.