Patent · US Expired

Positive current source

US5812020A · kind A · utility

7Cited by
6References
3Claims
0Family size

Assignee

Inventors

Key dates

Filing dateMay 23, 1997
Grant dateSep 22, 1998
Priority date
Expiry dateMay 23, 2017

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH03H11/0444
  • WIPO fieldBasic communication processes
  • WIPO sectorElectrical engineering

Abstract

A positive current source (PCS) for supplying common mode current. The PCS includes a pair of unity gain inverting single ended amplifiers that are connected in antiparallel across a pair of matched resistors. Alternately, the resistors can be connected across the inverting and non-inverting sides of a differential amplifier. A constant voltage is applied across the resistors to supply the common mode current (I.sub.cm) while maintaining a common mode resistance of R/2 and a differential mode resistance approaching infinity. The PCS has a common mode resistance which is small enough to maintain a stable common mode operating point with process variations providing minimal impact.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.