Adaptive capacitive touch sense control circuit
US7843249B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 2008 |
| Grant date | Nov 30, 2010 |
| Priority date | — |
| Expiry date | Dec 13, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/96073
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An adaptive capacitive touch sense control circuit includes a voltage buffer, a current setting resistor, a current mirror, a capacitor, a start comparator, an end comparator and a time-to-digital converter. The capacitor is connected with the current setting resistor. The circuit further includes a latch with a first control switch and a second control switch. The current setting resistor is switched between the ground and a voltage source through a switching element, so that when the current setting resistor is grounded, the first control switch is closed and the second control switch is opened, and when the current setting resistor is connected with the voltage source, the second control switch is closed and the first control switch is opened. An adaptive charging mode is adopted to sense a capacitance variation with a great ability of interference recognition, a simple structure, low power consumption and real time processing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.