Patent ID: 11954283
Assignee: TOUCH BIOMETRIX LIMITED
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 8:
9. A sensor array comprising a plurality of touch sensitive pixels, each pixel comprising:
a capacitive sensing electrode for accumulating a charge in response to proximity of a conductive object to be sensed;
a reference capacitor connected in series with the capacitive sensing electrode so that, in response to a control voltage, an indicator voltage is provided at the connection between the reference capacitor and the capacitive sensing electrode to indicate the proximity of the conductive object to be sensed;
a sense voltage-controlled impedance, VCI, having a control terminal connected so that the impedance of the sense VCI is controlled by the indicator voltage, wherein a conduction path of the sense VCI is connected to a readout line for providing readout signals to a readout circuit;
a select VCI having a conduction path connected in series between the conduction path of the sense VCI and a reference signal supply;
a reset VCI having a conduction path which connects a reset voltage source to the control terminal of the sense VCI,
wherein a control terminal of the select VCI is connected to a gate line for said pixel; and
wherein a first plate of the reference capacitor is connected to said gate line for the pixel, and wherein a second plate of the reference capacitor is connected to each of: the conduction path of the reset VCI, the control terminal of the sense VCI, and the capacitive sensing electrode.