Method of biasing mosfet amplifiers for constant transconductance
US5777518A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1996 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Oct 30, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/301
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A MOSFET amplifier device is biased to exhibit a substantially constant transconductance over a range of variations in power supply, temperature and process. A bias circuit includes a pair of MOS field effect devices, one of which is biased in a triode operating region with a constant reference drain-to-source terminal voltage and with a constant first reference drain-to-source terminal current. The other field effect device is biased in saturation by a circuit that derives a gate-to-source terminal bias voltage from the gate terminal voltage of the first device and the first reference voltage. A second reference current flows into the drain terminal of the second device, and a corresponding bias current is derived, for example, by mirroring the second reference current. The mirrored reference current is used to bias a MOS amplifier device, to maintain a substantially constant transconductance over the mentioned range of variations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.