Line driver with adaptive output impedance
US5936393A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1998 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Feb 23, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/0278
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A line driver comprising a first transistor (M1), a first operational transconductance amplifier (A1) and a reference resistor (10) for converting an input voltage (Vin) to a first current (i1) through the first transistor (M1). A second current i2=n*i1 flows through a second transistor (M2) which forms a 1:n current mirror with the first transistor (M1). The current i2 flows to a load (6), if so required via a transmission line (TL). The impedance of the load (6) is equal to the characteristic impedance RL of the transmission line (TL). Thus, the impedance seen by the line driver is equal to RL. A second operational transconductance amplifier (A2) counteracts reflected signals in the output signal (Vout) caused by mismatch between the output impedance of the current mirror (M1, M2) and the impedance seen by the line driver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.