Constant current circuit
US4327321A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1980 |
| Grant date | Apr 27, 1982 |
| Priority date | — |
| Expiry date | Jun 11, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/262
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A constant current circuit is provided which is capable of feeding a constant current to a load connected in series with the source-drain path of a load drive MOSFET. The circuit employs a current mirror comprising first and second P channel MOSFETs, and first and second N channel MOSFETs connected in series with the first and second P channel MOSFETs, respectively. To avoid dependence on variations in power source voltage and/or threshold voltage characteristics of the MOSFETs, a resistor is inserted between the first P and N channel MOSFET's and the gate of the load drive MOSFET is coupled to both the junction of the resistor and first N channel MOSFET and to the gate of the second N channel MOSFET. Variations of this basic arrangement are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.