Fingerprint sensor package having enhanced electrostatic discharge protection and associated methods
First Claim
1. A fingerprint sensor package comprising:
- a housing;
a fingerprint sensing integrated circuit within said housing and comprising a plurality of electric field sensing electrodes and processing circuitry connected thereto, said processing circuitry comprising at least one power supply line for external connection;
at least one external electrode carried by said housing for contact by a finger of a user;
an electrostatic discharge circuit within said housing and connected to said at least one external electrode for protecting said fingerprint sensing integrated circuit; and
a power supply isolation circuit within said housing and connected to the at least one power supply line for external connection for further protecting said fingerprint sensing integrated circuit;
said power supply isolation circuit comprising a DC power modulator and a DC power demodulator magnetically coupled thereto.
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Accused Products
Abstract
A fingerprint sensor package includes a fingerprint sensing integrated circuit within a housing and comprising a plurality of electric field sensing electrodes and processing circuitry connected thereto. At least one external electrode is carried by the housing for finger contact. An electrostatic discharge (ESD) circuit is provided within the housing and is connected to the at least one external electrode. An isolation circuit is connected to the at least one line of the processing circuitry for external connection. The external electrode and ESD circuit, as well as the line isolation circuit protect the integrated circuit against damage by voltage transients, such as ESD. The at least one external electrode may include first and second external electrodes. The first electrode may be connected to the electrostatic discharge circuit. The processing circuit may further comprise a wake-up circuit for selectively powering predetermined circuit portions responsive to sensing finger contact with the second external electrode. Moreover, the housing may define a recess therein to guide a finger of a user along a predetermined path of travel to contact the first external electrode before the second external electrode.
143 Citations
24 Claims
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1. A fingerprint sensor package comprising:
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a housing;
a fingerprint sensing integrated circuit within said housing and comprising a plurality of electric field sensing electrodes and processing circuitry connected thereto, said processing circuitry comprising at least one power supply line for external connection;
at least one external electrode carried by said housing for contact by a finger of a user;
an electrostatic discharge circuit within said housing and connected to said at least one external electrode for protecting said fingerprint sensing integrated circuit; and
a power supply isolation circuit within said housing and connected to the at least one power supply line for external connection for further protecting said fingerprint sensing integrated circuit;
said power supply isolation circuit comprising a DC power modulator and a DC power demodulator magnetically coupled thereto. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A fingerprint sensor package comprising:
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a housing;
a fingerprint sensing integrated circuit within said housing and comprising a plurality of electric field sensing electrodes and processing circuitry connected thereto, said processing circuitry comprising at least one data signal line for external connection;
at least one external electrode carried by said housing for contact by a finger of a user;
an electrostatic discharge circuit within said housing and connected to said at least one external electrode for protecting said fingerprint sensing integrated circuit; and
a data signal isolation circuit within said housing and connected to the at least one data signal line for external connection, said data signal isolation circuit comprising at least one series connected resistor. - View Dependent Claims (8, 9, 10, 11)
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12. A fingerprint sensor package comprising:
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a housing;
a fingerprint sensing integrated circuit within said housing and comprising a plurality of electric field sensing electrodes and processing circuitry connected thereto;
a circuit substrate mounting said fingerprint sensing integrated circuit and comprising at least one power supply rail extending only laterally adjacent said fingerprint sensing integrated circuits;
at least one external electrode carried by said housing for contact by a finger of a user; and
an electrostatic discharge circuit within said housing and connected to said at least one external electrode for protecting said fingerprint sensing integrated circuit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for making a fingerprint sensor package comprising:
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forming a fingerprint sensing integrated circuit including a plurality of electric field sensing electrodes and processing circuitry connected thereto, the processing circuitry comprising at least one data signal line for external connection;
positioning the fingerprint sensing integrated circuit within a housing;
forming at least one external electrode on the housing for contact by a finger of a user;
providing an electrostatic discharge circuit within said housing and connected to said at least one external electrode for protecting the fingerprint sensing integrated circuit; and
isolating the at least one data signal line for external connection by connecting a data signal isolation circuit to the at least one data signal line for further protecting said fingerprint sensing integrated circuit, the data isolation circuit comprising at least one series connected resistor. - View Dependent Claims (23, 24)
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Specification