Low voltage operational amplifier bias circuit and method
US5798673A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 1996 |
| Grant date | Aug 25, 1998 |
| Priority date | — |
| Expiry date | Mar 19, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/3067
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Low voltage operational amplifier (10) operates in a voltage range of one to eight volts over a temperature range of 0.degree. to 70.degree. centigrade. Op amp input stage (12) uses N-channel depletion-mode MOSFETs to provide amplification of the differential input and maintain constant transconductance. Source follower MOSFET (13) provides unity gain in transferring the AC signal, STAGE-1 OUTPUT, to the base of current sinking transistor (18). Sink control circuit (14) and source control circuit (22) generate the base drive currents for in transistors (18) and (24). The signal at the output of MOSFET (13) either causes the sink transistor (18) to sink current or the signal to be transposed by means of a translinear loop (16) and causes the source transistor (24) to source current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.