Key press detecting circuit
US8138811B2 · kind B2 · utility
6Cited by
3References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 13, 2009 |
| Grant date | Mar 20, 2012 |
| Priority date | — |
| Expiry date | May 13, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/22
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A key press detecting circuit for detecting the status of the key is provided. The key press detecting circuit comprises a discharging circuit which discharges when the key (K1) is pressed; and a voltage detecting circuit, which comprises a combination of a PNP transistor (T2) and a NPN transistor (T3), wherein when the discharging circuit discharges for a predefined period, the PNP transistor (T2) will be turn on, which causes the NPN transistor (T3) to be turned on and to output a second signal for a second function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.