Capacitance fingerprint sensing circuit and sensor

Capacitance fingerprint sensing circuit and sensor

  • CN 104,217,193 A
  • Filed: 03/20/2014
  • Published: 12/17/2014
  • Est. Priority Date: 03/20/2014
  • Status: Active Application
First Claim
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1. a capacitive fingerprint sensor circuit, it is characterized in that, comprise cancellation module and feedback amplifier, the first input end of described cancellation module is connected with the first external drive source, second input end of described cancellation module is by being connected with the second external drive source by the finger being pressed in this second input end, the output terminal of described cancellation module is connected with the input end of described feedback amplifier, the signal that described first external drive source and described second external drive source export is anti-phase each other, described first external drive source is sent to signal that the signal of described cancellation module and described second external drive source be coupled to described cancellation module and produces and offset, obtain the fingerprint induced signal relevant to the fingerprint degree of depth, the output terminal of described feedback amplifier exports the fingerprint induced signal after amplifying.

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