US5485107A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Backplane driver circuit
Assignee: Unisys Corp
•
Filing: 1995-01-09
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Granted: 1996-01-16
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Expires: 2015-01-09
Abstract
Abstract Disclosed is a backplane driver circuit 14' that temporarily clamps its output (PAD) to the termination supply voltage (V term ) during a low to high transition. This termination is applied for a limited period of time determined by the delay through an inverter 14'-15 and a transfer gate 14'-11. This circuit is effective in reducing both the inductive effects of quickly turning the driver off and reflections due to the backplane stubs (L1-L8). Another feature of the driver circuit is that the driver can be plugged into or pulled out of a running system for maintenance without turning the system off. In order to accomplish this, the driver goes into a high impedance state when its supply voltage is turned off.
Inventors
- 👤 Brian C. Lacey
- 👤 David F. Collins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:03
CPC Classifications
H; H03; H03K; H03K19/00; H03K19/0175; H03K19/0185; H03K19/018507; H03K19/018521
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
62 words
A backplane driver comprising: (a) means for receiving a termination voltage (V term ); (b) means for receiving an output signal (DATAOUT) and in response thereto providing a drive signal to an output terminal (PAD); and (c) means for temporarily clamping the voltage on the output terminal to approximately the termination voltage during a low to high transition of the output signal.
Claim 2
Dependent Claim
62 words
A backplane driver comprising: (a) means for receiving a termination voltage (V term ); (b) means for receiving an output signal (DATAOUT) and in response thereto providing a drive signal to an output terminal (PAD); and (c) means for temporarily clamping the voltage on the output terminal to approximately the termination voltage during a low to high transition of the output signal.
Claim 3
Dependent Claim
60 words
A backplane driver as recited in claim 1, wherein the driver has an output impedance as seen from the output terminal, and further comprising means for receiving a supply voltage (VDD) and means for setting the driver output impedance to a high impedance state when the supply voltage is turned off while the termination voltage (V term ) is present.
Claim 4
Dependent Claim
24 words
A backplane driver as recited in claim 1, further comprising means for protecting the driver during hot insertion of the driver to a backplane.
Claim 5
Dependent Claim
68 words
A backplane driver as recited in claim 1, wherein the driver has an output impedance and further comprising: means for receiving a supply voltage (VDD); means for setting the driver output impedance to a high impedance state when the supply voltage is turned off while the termination voltage (V term ) is present; and means for protecting the driver during hot insertion of the driver to a backplane.
Claim 6
Dependent Claim
87 words
A backplane driver as recited in claim 1, wherein the means for temporarily clamping the voltage on the output terminal to approximately the termination voltage comprises an P-channel FET having a substrate connected to a drain and tied to V term , an inverter, and a transfer gate arranged to temporarily clamp the output to approximately V term during a low to high transition of the output signal, whereby inductive effects of quickly turning the driver off and effects of reflections associated with the stub are reduced.
Claim 7
Dependent Claim
103 words
In a GTL driver that receives a supply voltage (VDD), a termination supply voltage (V term ), and an output signal (DATAOUT), and provides a drive signal to an output terminal coupled to a stub associated with a backplane, the improvement comprising an N-channel FET having a substrate connected to a drain and tied to V term , an inverter, and a transfer gate arranged to temporarily clamp the output to approximately V term during a low to high transition of the output signal, whereby inductive effects of quickly turning the driver off and effects of reflections associated with the stub are reduced.
Claim 8
Dependent Claim
103 words
In a GTL driver that receives a supply voltage (VDD), a termination supply voltage (V term ), and an output signal (DATAOUT), and provides a drive signal to an output terminal coupled to a stub associated with a backplane, the improvement comprising an N-channel FET having a substrate connected to a drain and tied to V term , an inverter, and a transfer gate arranged to temporarily clamp the output to approximately V term during a low to high transition of the output signal, whereby inductive effects of quickly turning the driver off and effects of reflections associated with the stub are reduced.
Claim 9
Dependent Claim
60 words
A GTL driver as recited in claim 6, wherein the driver has an output impedance as seen from the output terminal, and further comprising means for receiving a supply voltage (VDD) and means for setting the driver output impedance to a high impedance state when the supply voltage is turned off while the termination voltage (V term ) is present.
Claim 10
Dependent Claim
24 words
A GTL driver as recited in claim 6, further comprising means for protecting the driver during hot insertion of the driver to a backplane.
Claim 11
Independent Claim
62 words
A method for driving a backplane, comprising the steps of: (a) receiving a termination voltage (V term ); (b) receiving an output signal (DATAOUT) and in response thereto providing a drive signal to an output terminal (PAD); and (c) temporarily clamping the voltage on the output terminal to approximately the termination voltage during a low to high transition of the output signal.
Claim 12
Independent Claim
62 words
A method for driving a backplane, comprising the steps of: (a) receiving a termination voltage (V term ); (b) receiving an output signal (DATAOUT) and in response thereto providing a drive signal to an output terminal (PAD); and (c) temporarily clamping the voltage on the output terminal to approximately the termination voltage during a low to high transition of the output signal.
Claim 13
Dependent Claim
50 words
A method as recited in claim 9, further comprising the steps of receiving a supply voltage (VDD) and setting an output impedance of a driver coupled to said backplane to a high impedance state when the supply voltage is turned off while the termination voltage (V term ) is present.
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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) | 1999-01-15 | 1999-07-17 | 2000-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-15 | 2003-07-17 | 2004-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-15 | 2007-07-17 | 2008-01-16 | $7700.00 | Window Closed / Lapsed |