Low-noise preamplifier for magneto-resistive heads
US5122915A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1990 |
| Grant date | Jun 16, 1992 |
| Priority date | — |
| Expiry date | Sep 26, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2005/0018
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A preamplifer for use with a magneto-resistive playback head in which a d.c. current source provides current through a field effect transistor and the magneto-resistive element to ground. An operational transconductance amplifier included in a feedback loop provides a bias voltage for the field-effect transistor, whereby the voltage across the said magneto-resistive element is held constant while the resistance of said element changes. The resulting a.c. current flowing through the magneto-resistive element flows only through the feedback loop and an output resistor connected across the inputs of the operational transconductance amplifier. The amplification of the circuit is approximately the resistance of the output resistor divided by the resistance of the magneto-resistive element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.