Low power switch closure sensing circuit
AssigneeRCA Corporation
InventorRobert E. Wilson
Life of this patent
Estimating the term…
Abstract
A matrix array of row and column conductors, electrically isolated from each other, with a key switch connected between a row and a column conductor at each intersection of a row and a column conductor. Each column conductor is connected to a normally non-conducting current sourcing circuit and each row conductor is connected to a normally non-conducting current sinking circuit. Each key switch, when closed, connects its associated row and column conductors causing current to flow between that column's current sourcing circuit and that row's current sinking circuit. The current sourcing and the current sinking circuits associated with the particular switch closure then produce signals indicative of that key switch closure.
Claims5
The combination comprising:
- first and second conductors, electrically isolated from each other;
- a first normally non-conducting current sourcing circuit connected at one point to said first conductor;
- a second normally non-conducting current sinking circuit connected at one point to said second conductor;
- a normally open switch connected between said first and second conductors;
- and
- said switch, when closed, providing a conduction path for passing current between said current sourcing and said current sinking circuits rendering both conductive in response to the switch closure and immediately causing said first and second circuits to produce output signals indicative of the switch closure.
Dependencies are inferred from the claim text.