Four current transistor temperature sensor and method
US6554469B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 2001 |
| Grant date | Apr 29, 2003 |
| Priority date | — |
| Expiry date | Jul 6, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K7/01
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A four current transistor temperature sensor comprises a p-n junction, preferably the base-emitter junction of a bipolar transistor, which is driven with four different currents in a predetermined sequence. Each of the four currents induces a respective base-emitter voltage, which is measured. The temperature of the transistor is calculated based on the values of the four driving currents and the four measured base-emitter voltages. The four driving currents (I1, I2, I3 and I4) are preferably arranged such that I1=2*I3, I2=2*I4, I1/I2=A and I3/I4=A, where A is a predetermined current ratio. I1 and I2 produce respective base-emitter voltages which are subtracted from each other to produce &Dgr;Vbe1, and I3 and I4 produce respective base-emitter voltages which are subtracted from each other to produce &Dgr;Vbe2. When so arranged, the difference between &Dgr;Vbe1 and &Dgr;Vbe2 is entirely due to the effect of series base and emitter resistances rb and re. Therefore, the &Dgr;Vbe1−&Dgr;Vbe2 value provides a correction factor which enables temperature measurement errors due to rb and re to be eliminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.