Patent ID: 9652104
Date: 2017-05-16
CPC Classifications: G01R,G06F,H03K

Claim:
1. A capacitance voltage conversion circuit which converts a capacitance of each of a plurality of sensor capacitors into a voltage, the capacitance voltage conversion circuit comprising: a plurality of capacitance current conversion circuits disposed in respective correspondence with the sensor capacitors, each of the capacitance current conversion circuit configured to generate a detection current corresponding to a capacitance of a corresponding sensor capacitor; a current average circuit configured to average detection currents, which are generated by the capacitance current conversion circuits, to generate an average current; a plurality of current voltage conversion circuits disposed in respective correspondence with the sensor capacitors, each of the current voltage conversion circuit configured to convert a difference current between a corresponding detection current and the average current into a first output voltage, wherein in a standby mode, whether a user touches at least one of the sensor capacitors is determined on the basis of a difference current between the reference current and the average current; a reference capacitor; and a second capacitance current conversion circuit configured to generate a reference current corresponding to a capacitance of the reference capacitor.