Capacitance sensing circuit
US8363033B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 14, 2010 |
| Grant date | Jan 29, 2013 |
| Priority date | — |
| Expiry date | Oct 12, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0418
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A capacitance sensing circuit for a touch panel includes an analog capacitance-detecting circuit, a PWM-to-digital circuit and a self-calibration circuit. The analog capacitance-detecting circuit detects the capacitance of the touch panel based on a charging current, and converts the detected capacitance into a PWM control signal. The PWM-to-digital circuit converts the PWM control signal into a sensing count value based on a clock signal. The self-calibration circuit adjusts the value of the charging current or the frequency of the clock signal according to the difference between the range of the sensing count value and a predetermined detecting range. The predetermined detecting range can thus be adjusted for matching the range of the sensing count value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.