Monitoring circuit for a supply voltage
US5804995A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1997 |
| Grant date | Sep 8, 1998 |
| Priority date | — |
| Expiry date | Apr 24, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/16538
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The subject of the invention is a monitoring circuit for at least one supply voltage, having comparators that generate a first report signal if the supply voltage is below a predeterminable threshold value and a second report signal after a fixed warning time elapses. The supply voltage is supplied in a first circuit unit (4) to a first comparator (7). The first comparator is followed by a switch element, with which a capacitor (19), connected parallel to it and chargeable from an operating voltage source, can be short-circuited in order to lower the input voltage of a second comparator (13), disposed in the control unit (4), to below a second reference voltage that defines a limit value for the resetting of the report signal. The noninverting output of the second comparator (13) is followed by the base of an output transistor (14), whose emitter is connected to the negative pole of the operating voltage, the positive pole whereof is connected via a resistor (31) to the collector of the output transistor (14). The first report signal appears at the output transistor (14). The collector of the output transistor (14) is followed via a diode (20) by a capacitor (23), which in a second…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.