Hall-voltage slope-activated sensor
US5442283A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1993 |
| Grant date | Aug 15, 1995 |
| Priority date | — |
| Expiry date | Sep 3, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P3/488
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The Hall sensor circuit includes a Hall element that is preferably followed by a Hall-voltage amplifier, and a pole end of a magnet is preferably fixed adjacent to the Hall element. The amplifier output is connected directly to one of a pair of differential inputs of a Schmitt trigger circuit and is also connected, via a single or a dual-polarity track and hold circuit, to the other of the differential Schmitt inputs. The dual-polarity track and hold circuit causes the voltage across a capacitor to track positive and negative Hall voltage slopes, and to hold the positive-going peaks and negative-going peaks of the Hall voltage presented to the fore-mentioned other Schmitt input so that when the difference voltage between the Hall voltage and the held voltage of the capacitor exceeds a positive or negative threshold of the Schmitt circuit, the Schmitt circuit output changes binary state indicating the approaching edge or the receding edge of a ferrous-gear tooth. The dual-polarity track and hold circuit is made up of two complementary plus and a minus peak detector circuits, each including a bipolar transistor having an emitter connected to the voltage-holding capacitor, an operatio…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.