Circuit for sensing voltages beyond the supply voltage of the sensing circuit
US4890013A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 17, 1988 |
| Grant date | Dec 26, 1989 |
| Priority date | — |
| Expiry date | Jun 17, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A voltage sensing circuit wherein voltages that appear at first and second sensing nodes are converted into first and second currents which are proportional to their respective voltages. A comparing circuit compares the first current to the second current and generates a difference current proportional to the difference between the magnitudes of the two currents. A rectifier circuit rectifies the difference current, and the difference current is added to a reference current. The combined current is applied to the first input terminal of a comparator. The second input terminal of the comparator is coupled to a reference voltage, and the comparator indicates when the voltage created from the combined currents exceeds the reference voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.