US5166561A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Active intelligent termination
Assignee: Nortel Networks Ltd
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Filing: 1991-07-25
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Granted: 1992-11-24
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Expires: 2011-07-25
Abstract
Abstract An active intelligent termination circuit is designed to function as a self-switching clamp adapted to attenuate unwanted signals on a data bus. A field effect transistor is switched on or off in a conducting mode or non-conducting mode respectively in accordance with the data transmitted on the data bus. Any low level unwanted signals which may appear on the bus when data having a voltage level corresponding to a logic zero is present will be attenuated by the field effect transistor which is coupled to both the data bus and to a ground plane. The field effect transistor switches to the non-conducting mode when data corresponding to a logic level one is transmitted on the bus.
Inventors
- 👤 David K. Okura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:57
CPC Classifications
G; G11; G11C; G11C7/00; G11C7/10; G11C7/1048; G11C5/00; G11C5/06; G11C5/063; H; H03; H03K; H03K5/00; H03K5/125; H03K5/1252
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
147 words
A circuit for attenuating unwanted signals on a transmission line adapted to carry data signals, comprising: an inverter gate coupled to the transmission line for providing inverted data signals corresponding to the signals appearing on the transmission line; a flip-flop responsive to the inverted data signals and to a local clock signal for providing output signals; circuit means connected to the flip-flop for providing inverted output signals thereof; an AND gate responsive to the inverted data signals and to the inverted output signals from the flip-flop to provide ANDED signals; and a controllable transmission gate connected between the transmission line and terminal connected to a reference voltage, the controllable gate being responsive to the ANDED signals for providing a conducting path to the terminal from the transmission line in a first mode and for preventing conduction between the transmission line and the terminal in a second mode.
Claim 2
Dependent Claim
147 words
A circuit for attenuating unwanted signals on a transmission line adapted to carry data signals, comprising: an inverter gate coupled to the transmission line for providing inverted data signals corresponding to the signals appearing on the transmission line; a flip-flop responsive to the inverted data signals and to a local clock signal for providing output signals; circuit means connected to the flip-flop for providing inverted output signals thereof; an AND gate responsive to the inverted data signals and to the inverted output signals from the flip-flop to provide ANDED signals; and a controllable transmission gate connected between the transmission line and terminal connected to a reference voltage, the controllable gate being responsive to the ANDED signals for providing a conducting path to the terminal from the transmission line in a first mode and for preventing conduction between the transmission line and the terminal in a second mode.
Claim 3
Dependent Claim
16 words
The circuit as defined in claim 1 wherein the controllable gate is a field effect transistor.
Claim 4
Dependent Claim
151 words
A circuit for attenuating unwanted signals on a transmission line adapted to carry data signals, comprising: a controllable transmission gate operable in a first mode for conducting unwanted current from the transmission gate to a voltage reference terminal in response to unwanted signals on the transmission line and operable in a second mode for preventing the conduction of current from the transmission line to the terminal, the gate having a first terminal connected to the transmission line a second terminal connected to the voltage reference terminal and a control terminal, and a control circuit means for releasing the transmission gate from conducting in the first mode in response to a clock signal and to the data signals on the transmission line, said control circuit means being coupled to the transmission line via an inverter gate and having a control circuit output connected to the control terminal of the controllable transmission gate.
Claim 5
Dependent Claim
151 words
A circuit for attenuating unwanted signals on a transmission line adapted to carry data signals, comprising: a controllable transmission gate operable in a first mode for conducting unwanted current from the transmission gate to a voltage reference terminal in response to unwanted signals on the transmission line and operable in a second mode for preventing the conduction of current from the transmission line to the terminal, the gate having a first terminal connected to the transmission line a second terminal connected to the voltage reference terminal and a control terminal, and a control circuit means for releasing the transmission gate from conducting in the first mode in response to a clock signal and to the data signals on the transmission line, said control circuit means being coupled to the transmission line via an inverter gate and having a control circuit output connected to the control terminal of the controllable transmission gate.
Claim 6
Dependent Claim
72 words
A circuit as defined in claim 3 wherein the control circuit means comprises, a flip-flop responsive to the inverted data signals and to a local clock signal for providing output signals; inverting circuit means connected to the flip-flop for providing inverted output signals thereof; and an AND gate responsive to the inverted data signals and to the inverted output signals from the flip-flop to provide control signals to the controllable transmission gate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-11-24 | 1996-05-25 | 1996-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-24 | 2000-05-25 | 2000-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-24 | 2004-05-25 | 2004-11-24 | $7700.00 | Window Closed / Lapsed |