Temperature insensitive CMOS precision current source
US4595874A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1984 |
| Grant date | Jun 17, 1986 |
| Priority date | — |
| Expiry date | Sep 26, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/907
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A CMOS precision current source which is insensitive to changes in both ambient temperature and processing conditions. In particular, a CMOS circuit exhibits both a temperature dependent voltage (V(T)) and a temperature dependent on-chip resistance (R(T)) where the dependencies of both voltage and resistance are linear functions of temperature of the form y=mx+b. The ratio of the slopes (m.sub.V /m.sub.R) is constructed to be equal to the ratio of the y-intercepts (b.sub.v /b.sub.R), where this ratio is a constant value, denoted s. Therefore, since a constant output current I.sub.o is equal to V(T)/R(T), I.sub.o will be equal to the constant value s. Additionally, a constant reference voltage (V.sub.o) may also be provided with a minimal increase in the circuitry needed to provide the constant current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.