Circuit and method for programmably changing the transconductance of a transconductor circuit
US5994926A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1997 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Apr 16, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45076
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A programmably variable transconductance circuit (10) and method for varying its transconductance includes first and second current control input devices (16, 18), each having an input (17,19) to which a differential input voltage may be applied. A pair of current steering circuits (26, 28, 30, 32) are each connected in series with a respective one of the first and second current control devices (16, 18) for dividing respective currents in the first and second current control devices (16, 18) between a differential output current path (12, 14) and another current flow path, and a programmable voltage source (90) supplying V.sub.CONTROL is connected to control the current division by the current steering circuits (26, 28, 30, 32). The programmable voltage, V.sub.CONTROL, is provided by a programmable current control loop (90), which incorporates a master transconductance circuit, to establish a constant transconductance independently of temperature variations. A dynamically controllable resistance, such as an MOS transistor (24), or the like, is connected between the first and second current control input devices (16, 18), and a second voltage source (V.sub.GATE) is connected to the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.