Capacitance detecting circuit

A capacitance detecting circuit comprising:

• N induction units, where N is an integer larger than or equal to 1;
• a transferring capacitor configured to transfer charges to a capacitor of a scanned induction unit among the N induction units, wherein a first terminal of the transferring capacitor connects to the N induction units, respectively, and a second terminal of the transferring capacitor is grounded;
• a charging module configured to charge the transferring capacitor, wherein a first terminal of the charging module connects to the first terminal of the transferring capacitor, and a second terminal of the charging module connects to a first power supply;
• a discharging module configured to discharge the transferring capacitor and comprising a first resistor and a second switch, wherein a first terminal of the discharging module connects to the first terminal of the charging module and the first terminal of the transferring capacitor, respectively, and a second terminal of the discharging module is grounded;
• and
• a controller connected to the charging module, the transferring capacitor and the discharging module, respectively, and configured to control the second switch to switch on when a voltage of the transferring capacitor is larger than a preset threshold voltage, and to update a count value and detect a touch on the N induction units according to the count value.