Precision current source
US4399399A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1981 |
| Grant date | Aug 16, 1983 |
| Priority date | — |
| Expiry date | Dec 21, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/30
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A circuit for providing an output current the magnitude of which is substantially independent to variations in the power supply voltage applied thereto. The circuit comprises first and second current sourcing transistors, and a conventional .DELTA.V.sub.be /R current mirror circuit for setting the current sourced from the two transistors. At least one output transistor having its base and emitter electrodes coupled in parallel with the base and emitter electrodes of the two transistors is included for sourcing the output current. An operational amplifier having its inverting and non-inverting inputs connected with respective collectors of the two transistors and its output connected to the commonly connected bases of the two transistors and the output transistor is provided which maintains the collectors of the two transistors at equal potential levels even though the magnitude of the power supply voltage may vary so that the current produced at the collector of the output transistor does not vary substantially.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.