Low voltage current sense amplifier
US5969574A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 1998 |
| Grant date | Oct 19, 1999 |
| Priority date | — |
| Expiry date | Jun 4, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/0092
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An accurate, low voltage, low parts-count current sense amplifier can be employed to sense either high side or low side currents. A pair of transistors are connected in a common-base configuration and biased with equal currents, with a sense resistor connected between their respective emitter circuits. A sensed current develops a voltage across the sense resistor which unbalances the transistor currents. A third transistor is connected to provide a feedback current to detect and correct the current imbalance; the feedback current is directly proportional to the sensed current, and serves as the current sense amplifier's output. The current sense amplifier requires only three transistors, can be realized with bipolar or FET devices of either polarity, and can operate at supply voltages as low as about 1.1 volts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.