Multiple capacitive (button) sensor with reduced pinout
US8653741B2 · kind B2 · utility
5Cited by
3References
17Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jan 18, 2012 |
| Grant date | Feb 18, 2014 |
| Priority date | — |
| Expiry date | Aug 10, 2032 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A capacitive touch sensor and LED driver device achieves a reduction in pin count by multiplexing LED drive functionality and capacitive sense functionality on each input/output pin. A control circuit switches between LED drive mode and capacitive sense mode at a frequency of approximately 200 Hz, although other switching frequencies can be used. A bias driver functions as a current sink for LEDs in LED drive mode and can also be used to drive a bias voltage to the LEDs during capacitive sense mode to improve noise immunity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.