Capacitance sensor using relaxation oscillators
US7307485B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 2005 |
| Grant date | Dec 11, 2007 |
| Priority date | — |
| Expiry date | Jan 17, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/26
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An apparatus that may be used to sense capacitance, as well as other functions. The apparatus includes a comparator circuit with hysteresis, a capacitor, and a current driver. The comparator circuit with hysteresis includes a first input and an output. The capacitor is coupled to the first input of the comparator circuit with hysteresis. The current driver is coupled to the output of the comparator circuit with hysteresis and to the capacitor. The current driver reciprocally sources and sinks a drive current through a terminal of the capacitor to oscillate a voltage potential at the terminal of the capacitor between a low reference potential and a high reference potential. The current driver is responsive to the output of the comparator circuit with hysteresis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.