Signalling between independently powered electrical circuit cards
US6336591B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1998 |
| Grant date | Jan 8, 2002 |
| Priority date | — |
| Expiry date | Nov 2, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/165
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A plurality of circuit cards include at least a first card having a first internal power rail, an earth connection, respective operating circuits powered from the first power rail, external terminals coupled to its operating circuit, and a first external connection. A second of the plural cards has a second internal power rail, an earth connection, respective operating circuits powered from the second power rail, external terminals coupled to its operating circuit, and a second external connector. The first card includes a bipolar transistor with an emitter-base junction forwardly biased in response to normal voltage between the first power rail and the earth connection and a collector connected to the first external connector. The second card includes a resistive connection between its second internal power rail and the second external connector and circuits responsive to changes in voltage level at the second connector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.