Fingerprint identification system and electronic device

Abstract

The invention provides a fingerprint identification system comprising a plurality of first pixel circuits, a first sensing circuit, at least one second pixel circuit, a second sensing circuit, and a differential amplification circuit. The first sensing circuit is used for sensing a contact capacitor and outputting a first output signal, wherein the first output signal comprises a large signal component and a small signal component, and the small signal component is related to a variation of the contact capacitor. The second sensing circuit is used for outputting a second output signal, and the second output signal is equal to the large signal component. The differential amplification circuit is used for amplifying the difference between the first output signal and the second output signal in order to generate an amplified output signal, and the amplified output signal is related to the small signal component.

Description

technical field [0001] The invention relates to a fingerprint identification system and an electronic device, in particular to a fingerprint identification system and an electronic device capable of reducing the influence of parasitic capacitance. Background technique [0002] With the rapid development of technology, more and more portable electronic devices such as mobile phones, digital cameras, tablet computers, and notebook computers have become necessary tools in people's lives. Since portable electronic devices are usually used by individuals and have a certain degree of privacy, the data stored in them, such as phonebooks, photos, personal information, etc., are privately owned. Once the electronic device is lost, the data may be used by others to cause unnecessary loss. Although there is currently a password protection method to prevent the electronic device from being used by others, the password is easy to leak or be cracked, and has low security. Moreover, the ...

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Problems solved by technology

However, there will be a parasitic capacitance between the contact layer and the shielding layer, and the capacitance value of the parasitic capacitance is often greater than the capacitance value of the contact capacitance generated by the contact, which will affect the capacitance sensing circuit or the capacitive fingerprint recognition system to judge the capacitance value of the contact capacitance. , so that the accuracy of fingerprint identification is reduced

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