Capacitive touch circuit
US8330735B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 2009 |
| Grant date | Dec 11, 2012 |
| Priority date | — |
| Expiry date | Apr 14, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/94026
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A capacitive touch circuit includes a single comparator, a reference voltage control unit, a resistance adjusting unit, a delay unit, and a relaxation oscillation control unit. The comparator has a first input terminal, a second input terminal, and an output terminal. The reference voltage control unit is electrically connected to the second input terminal and includes a high level voltage source, a low level voltage source, and a voltage switching controller. The voltage switching controller electrically connects either the high level voltage source or the low level voltage source to the second input terminal of the single comparator according to an output signal of the single comparator. The relaxation oscillation control unit is electrically connected to the resistance adjusting unit, the delay unit, and the reference voltage control unit. The relaxation oscillation control unit outputs a relaxation oscillation signal, and the frequency of the relaxation oscillation signal varies according to the resistance set by the resistance adjusting unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.