Finger biometric sensing device including drive signal nulling circuitry and related methods

摘要

A finger biometric sensing device may include drive circuitry capable of generating a drive signal and an array of finger biometric sensing pixel electrodes cooperating with the drive circuitry and capable of generating a detected signal based upon placement of a finger adjacent the array of finger biometric sensing pixel electrodes. The detected signal may include a relatively large drive signal component and a relatively small sense signal component superimposed thereon. The finger biometric sensing device may also include a gain stage coupled to the array of finger biometric sensing pixel electrodes, and drive signal nulling circuitry coupled to the gain stage capable of reducing the relatively large drive signal component from the detected signal.

主权项

1. A finger biometric sensing device comprising:
drive circuitry comprising a finger coupling electrode and a voltage generator coupled thereto; an array of finger biometric sensing pixel electrodes adjacent the finger coupling electrode, cooperating with the drive circuitry, and capable of generating a detected signal based upon placement of the finger adjacent the array of finger biometric sensing pixel electrodes, the detected signal including a drive signal component and a finger biometric sense signal component superimposed thereon, the finger biometric sense signal component comprising finger biometric characteristic data for performing an authentication function; and drive signal nulling circuitry capable of reducing the drive signal component from the finger biometric sense signal component.