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公开(公告)号：US09953204B2
公开(公告)日：2018-04-24
申请号：US15399124
申请日：2017-01-05
Applicant: Fingerprint Cards AB
Inventor： Rolf Sundblad , Emil Hjalmarson , Erik Säll , Allan Olsson , Klaas-Jan De Langen
CPC classification number: G06K9/0002 , G06K9/00087 , G06K9/03 , H02M3/07
Abstract: A fingerprint sensing system comprising a device connection interface including a device reference potential input, a sensing arrangement, and sensing reference potential providing circuitry. The sensing arrangement includes multiple sensing structures and read-out circuitry connected to each of the sensing structures. The sensing reference potential providing circuitry provides a sensing reference potential to the sensing arrangement in the form of a sensing reference signal alternating between a first sensing reference potential and a second sensing reference potential, and comprises a first capacitor; a second capacitor; charging circuitry; and switching circuitry for alternatingly switching the sensing reference potential providing circuitry between a first state in which the first capacitor and the second capacitor are connected in parallel to the charging circuitry; and a second state in which the first capacitor and the second capacitor, when charged, are connected in series between the device reference potential input and the sensing arrangement.
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公开(公告)号：US20170308730A1
公开(公告)日：2017-10-26
申请号：US15399124
申请日：2017-01-05
Applicant: Fingerprint Cards AB
Inventor： Rolf Sundblad , Emil Hjalmarson , Erik Säll , Allan Olsson , Klaas-Jan De Langen
CPC classification number: G06K9/0002 , G06K9/00087 , G06K9/03 , H02M3/07
Abstract: A fingerprint sensing system comprising a device connection interface including a device reference potential input, a sensing arrangement, and sensing reference potential providing circuitry. The sensing arrangement includes multiple sensing structures and read-out circuitry connected to each of the sensing structures. The sensing reference potential providing circuitry provides a sensing reference potential to the sensing arrangement in the form of a sensing reference signal alternating between a first sensing reference potential and a second sensing reference potential, and comprises a first capacitor; a second capacitor; charging circuitry; and switching circuitry for alternatingly switching the sensing reference potential providing circuitry between a first state in which the first capacitor and the second capacitor are connected in parallel to the charging circuitry; and a second state in which the first capacitor and the second capacitor, when charged, are connected in series between the device reference potential input and the sensing arrangement.
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