Capacitance change measuring circuit of capacitive sensor device, capacitive sensor module, method of measuring capacitance change of capacitive sensor device, and electronic device
US8174271B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 2009 |
| Grant date | May 8, 2012 |
| Priority date | — |
| Expiry date | Nov 3, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/960725
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Scanning rate in a capacitance change measuring circuit for a capacitive sensor device is enhanced. The circuit includes: an electrode drive section line-sequentially applying an input pulse signal to a plurality of columns of first electrode patterns in the capacitive sensor device; a peak hold circuit storing a peak level of a detection signal extracted from each column of second electrode patterns into a capacitive element as a corresponding potential; a current source initializing the potential in the capacitive element within one period of the input pulse signal; a comparator comparing the potential in the capacitive element with a reference value; and determination sections each determining whether or not an input operation using a human body or the like is executed, based on a timing information and a reference timing information, the timing information representing a timing when the potential held in the capacitive element crosses the reference value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.