Low noise voltage-biasing amplifier for magnetoresistive element
US5204789A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 1991 |
| Grant date | Apr 20, 1993 |
| Priority date | — |
| Expiry date | Jan 13, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/02
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A circuit for concurrently producing low noise electrical output signals which are amplified representations of signals produced by a magnetoresistive (MR) element and protecting said element from electrical short circuits which can occur between said element and its environment. A first feedback loop comprises (a) an input amplifier for amplifying a signal current from the MR element and (b) a source of bias current for biasing the MR element with a bias voltage. An input amplifier is concurrently biased by said current and amplifies a signal current from the MR element for producing a circuit output signal corresponding to dRh/RhRh and in which any differential direct current (dc) output offset error is minimized. (RhRh is the square of the time-averaged resistance of the MR element and dRh is the magnetic-signal-induced change in the resistance of the MR element.) A second feedback loop, electrically in series with the first feedback loop, biases the MR element toward a preselected reference potential and concurrently prevents flow of a current sufficient to damage the MR element in the event of a short circuit occurring between the MR element and its environment (e.g. the recor…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.