Integrated circuit bus switching circuit
US4945267A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 10, 1989 |
| Grant date | Jul 31, 1990 |
| Priority date | — |
| Expiry date | Jan 10, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/1732
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A circuit is provided for switching an internal bus of an integrated circuit between an input/output pad on the integrated circuit and a circuit node of the integrated circuit. A first switch is connected between the input/output pad and the internal bus. A second switch is connected between the circuit node and the internal bus. A high voltage detector senses the presence or absence of a voltage exceeding a preselected threshold on the input-output pad. The high voltage detector assumes a first state if the voltage on the input/output pad exceeds the preselected threshold, and assumes a second state if the voltage on the input/output pad does not exceed the preselected threshold. Switch control circuitry responsive to the high voltage detector activates either the first or second switch depending upon the output of the high voltage detector. Circuitry is provided to prevent the first and second switches from being active simultaneously and for lowering the capacitance of the input/output pad.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.