Bias voltage and constant current supply circuit
US4808909A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 15, 1987 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Oct 15, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/185
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A circuit for providing a constant current and a constant bias voltage is described. The circuit includes two paths coupled between a positive voltage supply +V.sub.S and a negative voltage supply -V.sub.S. Each path inlcudes a Zener diode and a enhancement mode field effect transistor (FET) device (the FET device being coupled in a diode configuration) which are connected in series. Each path of the circuit further includes an FET device and an associated resistor combination, coupled in series with the Zener diode and the diode-coupled FET device. The FET device and the associated resistor function as a current source component. A gate terminal of each FET device of the current source component is coupled across the Zener diode and the diode-coupled FET device of the other circuit path. This cross-coupling between the two paths provides compensation, in addition to that provided by the Zener diode characteristics, for variations in circuit parameters, such as changes in the voltage supplies, thereby permitting a stable bias voltage to be generated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.