System for detecting irregular operation of switch state verification circuit
US4956637A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 29, 1988 |
| Grant date | Sep 11, 1990 |
| Priority date | — |
| Expiry date | Apr 29, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/04
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A system for debouncing a switch circuit includes a sample circuit for providing an initial determination of the switch status, and a debounce circuit connected to operate on the output of the sample or sensing circuit to verify the actual switch status by providing a confirmation signal. The system of the invention accumulates a count related either to the rate at which the sample circuit operates, or the actual changes in state indicated by latches coupled to the sample circuit. If the count accumulates to a predetermined number before being cleared by a confirmation signal verifying the switch status, then the irregular operation is signalled. This identifies a continuous, rapid alternation between different switch states without a confirmation of an actual state change, which would otherwise be undetected by system operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.