Transistor current source
US4381484A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 1981 |
| Grant date | Apr 26, 1983 |
| Priority date | — |
| Expiry date | Jun 1, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/265
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A PNP transistor current source for sourcing current to a load connected thereto the magnitude of the sourced current being many times greater than the magnitude of a small constant reference current supplied to the current source. The PNP current source is suitable for being manufactured in monolithic integrated circuit form as the current source is made substantially independent to current amplification factor variations normally associated with typical integrated circuit fabrication processes. The PNP current source comprises a pair of PNP transistors having the respective base and emitters commonly coupled together with the emitter area of the output PNP device being N times greater than the emitter area of the other PNP device and including a feedback loop having a current mirror which is coupled between the collector of the other PNP device and the output of the reference current source, a Darlington amplifier coupled between the output of the reference current source and the commonly connected bases of the two PNP transistors wherein the collector currents of the two PNP transistors are made independent to beta variations of each devices.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.