US5422608A
Expired / Lapsed
US
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Adaptive transmission line termination
Assignee: Texas Instruments Inc
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Filing: 1994-08-30
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Granted: 1995-06-06
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Expires: 2014-08-30
Abstract
Abstract An adaptive transmission line termination which includes a variable voltage controlled resistor (16) connected either in series with the sending end of transmission line (10) or in parallel with the receiving end of line (10). The resistance of resistor (16) is varied in dependence upon the half voltage appearing on line (10) in order to match the characteristic impedance of line (10) for the series or source termination case. In the parallel termination case, the resistance of resistor (34) is varied in dependence upon the voltage appearing at the input of gate (14) to match the characteristic impedance of line (10).
Inventors
- 👤 Louis Y. Levesque
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:33
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/28; H03H11/30
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
69 words
A self adaptive transmission line termination comprising: a driving gate connected to a transmission line input having a prescribed output impedance; and a voltage controlled self adaptive resistive element coupled at the output of said driving gate, the resistance of said self adaptive resistive element being varied in response to the voltage appearing on the transmission line in order to match the overall characteristic impedance of the transmission line.
Claim 2
Dependent Claim
69 words
A self adaptive transmission line termination comprising: a driving gate connected to a transmission line input having a prescribed output impedance; and a voltage controlled self adaptive resistive element coupled at the output of said driving gate, the resistance of said self adaptive resistive element being varied in response to the voltage appearing on the transmission line in order to match the overall characteristic impedance of the transmission line.
Claim 3
Dependent Claim
28 words
The adaptive transmission line termination of claim 1 wherein said resistive element is connected in series with the transmission line at the sending end of the transmission line.
Claim 4
Dependent Claim
24 words
The adaptive transmission line termination of claim 1 wherein said resistive element is connected in parallel at the receiving end of the transmission line.
Claim 5
Dependent Claim
15 words
The adaptive transmission line termination of claim 1 wherein said resistive element comprises a transistor.
Claim 6
Dependent Claim
16 words
The adaptive transmission line termination of claim 4 wherein said transistor comprises a field effect transistor.
Claim 7
Dependent Claim
30 words
The adaptive transmission line termination of claim 1 and further comprising an amplifier, having its input connected to the transmission line and its output connected to control said resistive element.
Claim 8
Dependent Claim
35 words
The adaptive transmissions line termination of claim 6 and further comprising detection circuitry connected between the transmission line and the input of said amplifier, said detection circuitry detecting half voltage variations on the transmission line.
Claim 9
Dependent Claim
68 words
A self adaptive transmission line termination comprising: a variable resistor coupled to a transmission line; and a voltage sensor for sensing the voltage on the transmission line and for generating a continuous control signal depending upon the voltage on the transmission line, said variable resistor dependent upon said continuous control signal to constantly vary the impedance of the termination to match the overall impedance of the transmission line.
Claim 10
Dependent Claim
68 words
A self adaptive transmission line termination comprising: a variable resistor coupled to a transmission line; and a voltage sensor for sensing the voltage on the transmission line and for generating a continuous control signal depending upon the voltage on the transmission line, said variable resistor dependent upon said continuous control signal to constantly vary the impedance of the termination to match the overall impedance of the transmission line.
Claim 11
Dependent Claim
17 words
The adaptive transmission line termination of claim 8 wherein said variable resistor comprises a field effect transistor.
Claim 12
Dependent Claim
24 words
The adaptive transmission line termination of claim 8 wherein said variable resistor is connected in series with the sending end of the transmission line.
Claim 13
Dependent Claim
24 words
The adaptive transmission line termination of claim 8 wherein said variable resistor is connected in parallel with the receiving end of the transmission line.
Claim 14
Dependent Claim
29 words
The adaptive transmission line termination of claim 8 and further comprising an amplifier having its input connected to the transmission line and its output connected to control said resistor.
Claim 15
Dependent Claim
35 words
The adaptive transmission line termination of claim 12 and further comprising detection circuitry connected between the transmission line and the input of said amplifier, said detection circuitry detecting half voltage variations on the transmission line.
Claim 16
Dependent Claim
27 words
The adaptive transmission line termination of claim 13 wherein said detection circuitry comprises: a peak detector circuit whose output is connected to the input of said amplifier.
Claim 17
Dependent Claim
28 words
The adaptive transmission line termination of claim 9 wherein said control signal is applied to the gate of said field effect transistor to control the source resistance thereof.
Claim 18
Dependent Claim
33 words
The adaptive transmission line termination of claim 15 wherein the gate of said field effect transistor is biased below pinch-off, such that the source resistance of said field effect transistor is linearly variable.
Claim 19
Independent Claim
75 words
A method of self adaptively varying impedance of a transmission line termination comprising: constantly sensing the voltage on a transmission line; constantly comparing the sensed voltage with a reference voltage level and generating a control signal in response to variances of the sensed voltage; and constantly varying the magnitude of a resistor coupled to the transmission line in response to said control signal, such that the resistor matches the overall impedance of the transmission line.
Claim 20
Independent Claim
75 words
A method of self adaptively varying impedance of a transmission line termination comprising: constantly sensing the voltage on a transmission line; constantly comparing the sensed voltage with a reference voltage level and generating a control signal in response to variances of the sensed voltage; and constantly varying the magnitude of a resistor coupled to the transmission line in response to said control signal, such that the resistor matches the overall impedance of the transmission line.
Claim 21
Dependent Claim
35 words
The method of adaptively varying the impedance of a transmission line termination of claim 17 and further comprising applying said control signal to the gate of a field effect transistor to vary the resistance thereof.
Claim 22
Dependent Claim
31 words
The method of adaptively varying the impedance of a transmission line termination of claim 17 and further comprising coupling the resistor in series to the sending end of the transmission line.
Claim 23
Dependent Claim
31 words
The method of adaptively varying the impedance of a transmission line termination of claim 17 and further comprising coupling the resistor in parallel to the receiving end of the transmission line.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-06-05 | 1998-12-05 | 1999-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-05 | 2002-12-05 | 2003-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-05 | 2006-12-05 | 2007-06-06 | $7700.00 | Window Closed / Lapsed |