FINGERPRINT SENSING DEVICE WITH COMMON MODE SUPPRESSION

摘要

The present invention relates to a fingerprint sensing device for sensing a fingerprint pattern of a finger, the fingerprint sensing device comprising at least a first sensing structure and a second sensing structure; and at least a first charge amplifier and a second charge amplifier. Each charge amplifier comprises: a first input; a second input; an output; and at least one amplifier stage between the first and second inputs, and the output. The output is capacitively coupled to the first input. The first input of the first charge amplifier is connected to the first sensing structure; the first input of the second charge amplifier is connected to the second sensing structure; and the output of the first charge amplifier is capacitively coupled to the first input of the second charge amplifier to suppress the common mode component.

主权项

1. A fingerprint sensing device for sensing a fingerprint pattern of a finger, said fingerprint sensing device comprising:
a plurality of electrically conductive sensing structures including at least a first sensing structure and a second sensing structure; and charge sensing circuitry connected to said sensing structures, said charge sensing circuitry including a set of charge amplifiers comprising at least a first charge amplifier and a second charge amplifier, each comprising:
a first input;a second input;an output; andat least one amplifier stage between said first and second inputs, and said output,said output being capacitively coupled to said first input, wherein:
the first input of said first charge amplifier is connected to said first sensing structure;the first input of said second charge amplifier is connected to said second sensing structure; andthe output of said first charge amplifier is capacitively coupled to the first input of said second charge amplifier.