Current mirror circuit and method for providing zero temperature coefficient trimmable current ratios
US4673867A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 1986 |
| Grant date | Jun 16, 1987 |
| Priority date | — |
| Expiry date | Jun 30, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/907
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A resistively trimmed current mirror circuit including a diode coupled in parallel to the base-emitter conduction path of a transistor and to which a reference current is supplied to produce a proportional output current at the collector of the transistor. A trimmable resistor is connected in the collector-emitter conduction path of the transistor which is adjusted to vary the output current for a given reference current to trim the ratio between the two currents. By making the reference current a thermal current, i.e., a current whose magnitude is proportional to thermal voltage and inversely proportional to resistance, the trimmed ratio remains temperature independent after being trimmed to a desired value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.