Capacitive sensor interface and method
US9214938B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 2012 |
| Grant date | Dec 15, 2015 |
| Priority date | — |
| Expiry date | Feb 22, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/9622
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Electronic interface and method for reading a capacitive sensor that includes one input capacitor (30) or several input capacitors, in which the capacitive sensor is excited with a two-level voltage (Vlow, Vhigh) and read by a charge-sense amplifier whose output is sampled in four successive instants. An evaluation unit (333) is arranged to compute two difference values (V12, V34) between two pairs of samples corresponding to different voltage levels and to combine said difference values into an output value (V_out_raw) proportional to the charge transferred to the input of the charge-sense amplifier and an error value (error_bit) sensitive to a time derivative of a noise current din/dt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.