Apparatus and method for reducing parasitic capacitive coupling and noise in fingerprint sensing circuits
USRE45650E1 · kind E1 · reissue
Assignee
Inventors
Key dates
| Filing date | Aug 22, 2013 |
| Grant date | Aug 11, 2015 |
| Priority date | — |
| Expiry date | Aug 22, 2033 |
Classification
- Technology area (CPC —)General
Abstract
A fingerprint sensing circuit for reducing noise and parasitic capacitive coupling is disclosed in one embodiment of the invention as including a plurality of transmitting elements to sequentially emit a probing signal. A digital ground is provided to ground digital components in the fingerprint sensing circuit. A quiet ground, separate from and quieter than the digital ground, is provided to ground transmitting elements that are not transmitting the probing signal. Similarly, control logic is provided to connect, to the quiet ground, transmitting elements that are not transmitting the probing signal, while disconnecting, from the quiet ground, transmitting elements that are emitting the probing signal. The quiet ground helps to reduce the adverse effects of parasitic capacitive coupling and noise on the inactive transmitting elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.