Capacitance measurement circuit with dynamic feedback
US8174273B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 7, 2010 |
| Grant date | May 8, 2012 |
| Priority date | — |
| Expiry date | Nov 27, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/96073
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods, devices, and systems that measure capacitance are disclosed. Typically, an accumulator circuit couples to the capacitance and includes an accumulator and switch(es) that charge the accumulator over a series of switch-controlled charging or discharging cycles governed by a first control signal. The accumulator circuit provides an accumulator signal based on the charge on the first accumulator. A discharge circuit couples to the accumulator circuit and includes an optional variable current device, the discharge circuit partially discharging the accumulator based on a second control signal. A control circuit, which couples to the accumulator circuit and the discharge circuit, dynamically adjusts the first and/or second control signals to keep the accumulator signal in a desired range. The dynamically adjusted control signal can be used as a measure of the capacitance. Such methods and systems may be used in capacitive touch sensing devices such as capacitive buttons and capacitive touch panels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.