Magnetic field sensor
US5438990A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1993 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Nov 12, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N59/00
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An implantable medical device uses a solid-state sensor for detecting the application of an external magnetic field. The sensor includes first and second split-drain field-effect transistors (MAGFETs) which are cross-coupled such that an external magnetic field perpendicular to the channel regions of the MAGFETs causes an increase in current through one split-drain half of each MAGFET, and a decrease in current through the other split-drain half of each MAGFET. The sensor also includes a high-gain differential amplifier coupled between the MAGFETs for detecting changes in the current conducted through the respective split-drain halves, and produces an output voltage which changes upon application of an external magnetic field to the implantable medical device. The magnetic sensor operates at low power supply voltages and bias currents available in implantable medical devices such as a cardiac pacemaker, so that current drain and power consumption are minimized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.