Capacitance detecting circuit and detecting method, and fingerprint sensor employing the same
US7102364B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 2004 |
| Grant date | Sep 5, 2006 |
| Priority date | — |
| Expiry date | Jan 11, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0446
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A capacitance detecting circuit detects, in terms of voltage, change in capacitance at intersections of a plurality of column lines and a plurality of row lines crossing each other. The capacitance detecting circuit includes a column-line driving unit for driving a column line; a row-line selector for selecting a specific row line from the plurality of row lines; and a capacitance calculator for calculating a capacitance at an intersection of the specific row line and the driven column line based on a reference current that flows in relation to a reference capacitance and a current that flows in relation to the capacitance at the intersection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.