Switched-transconductance circuit within integrated T-switches
US6040732A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 9, 1997 |
| Grant date | Mar 21, 2000 |
| Priority date | — |
| Expiry date | Apr 9, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/72
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A switched-transconductance circuit for use in a multiplexer circuit includes integrated T-switches to provide isolation between each of the differential voltage inputs of a transconductance stage and: (1) a respective differential current output of the transconductance stage, and (2) the opposite polarity voltage input of the transconductance stage. Each of a pair of first switches, which are enabled only when the transconductance circuit is disabled, is connected between a differential current output of the transconductance stage and a circuit ground. Each of a pair of second switches, e.g., cascode transistors, which are biased to be turned on only when the transconductance circuit is enabled, is coupled between the output of the transconductance stage and an output of the transconductance circuit. A third switch is connected between a common-emitter node of a differential pair of input transistors included in the transconductance stage and a circuit ground. By turning on the third switch: (1) current from a current source driving the differential pair of input transistors is steered away from the input transistors so as to disable the transconductance stage, and (2) a low imped…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.