Keypad with 1-bit capacitive touch sensing analog front end with sparse multi-touch detection
US9524069B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 25, 2015 |
| Grant date | Dec 20, 2016 |
| Priority date | — |
| Expiry date | Jun 17, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/960725
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A capacitive touch keypad may receive a touch by a conductive object to one or more keys of the keypad, in which the keys each have a separate capacitive key electrode. The touched locations may be determined by precharging a pseudo-randomly selected set of key electrodes a number (M) of iterations while the keyboard is being touched, producing a sense voltage for each iteration by coupling all of the key electrodes to a reference capacitor, producing a 1-bit sense measurement for each iteration by comparing the sense voltage to a reference voltage to form a set of M 1-bit sense measurement, and by applying a modified binary iterative hard threshold (BIHT) algorithm to the set of M 1-bit sense measurements, in which only the non-zero locations of the solution are monitored in each iteration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.