US5686872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Termination circuit for computer parallel data port
Assignee: Winbond Electronics Corp
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Filing: 1995-03-13
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Granted: 1997-11-11
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Expires: 2015-03-13
Abstract
Abstract Reflections and cross talk in a high-speed, bidirectional transmission line are minimized by terminating the transmission line with a network including a "serial" resistor connected in series between an end of the transmission line and a parallel (e.g. data) port, a "pull-up" resistor connected to the transmission line side of the serial resistor, and a capacitor connected between the parallel port side of the serial resistor and ground. Optionally, a diode is connected between the pull-up resistor and a bias potential. A variety of exemplary values for these components (i.e., serial resistor, pull-up resistor, capacitor) are discussed, in the context of particular signals. Preferably, the capacitor and the resistors are positioned as close as possible to the connector.
Inventors
- 👤 Rafael Fried
- 👤 Erez Bar-Niv
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:55
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/0264; H04L25/0278; H04L25/028; H04L25/0292
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
91 words
Termination circuit for a transmission line having an end connected to a parallel port, comprising: a serial resistor having a first terminal connected to the parallel port and a second terminal connected to the end of the transmission line; a pull-up resistor having a third terminal connected to the second terminal of the serial resistor and having a fourth terminal connected to a supply voltage; and a capacitor having a fifth terminal connected to the first terminal of the serial resistor and having a sixth terminal connected to a ground potential.
Claim 2
Dependent Claim
91 words
Termination circuit for a transmission line having an end connected to a parallel port, comprising: a serial resistor having a first terminal connected to the parallel port and a second terminal connected to the end of the transmission line; a pull-up resistor having a third terminal connected to the second terminal of the serial resistor and having a fourth terminal connected to a supply voltage; and a capacitor having a fifth terminal connected to the first terminal of the serial resistor and having a sixth terminal connected to a ground potential.
Claim 3
Dependent Claim
25 words
Termination circuit according to claim 1, wherein the serial resistor has a resistance of 33 ohms; and the capacitor has a capacitance of 470 picofarads.
Claim 4
Dependent Claim
25 words
Termination circuit according to claim 1, wherein the serial resistor has a resistance of 33 ohms; and the capacitor has a capacitance of 330 picofarads.
Claim 5
Dependent Claim
16 words
Termination circuit according to claim 3, wherein the pull-up resistor has a resistance of 4,700 ohms.
Claim 6
Dependent Claim
25 words
Termination circuit according to claim 1, wherein the serial resistor has a resistance of 100 ohms; and the capacitor has a capacitance of 680 picofarads.
Claim 7
Dependent Claim
16 words
Termination circuit according to claim 5, wherein the pull-up resistor has a resistance of 4,700 ohms.
Claim 8
Dependent Claim
25 words
Termination circuit according to claim 1, wherein the serial resistor has a resistance of 22 ohms; and the capacitor has a capacitance of 220 picofarads.
Claim 9
Dependent Claim
16 words
Termination circuit according to claim 7, wherein the pull-up resistor has a resistance of 4,700 ohms.
Claim 10
Dependent Claim
16 words
Termination circuit according to claim 1, wherein the pull-up resistor has a resistance of 1,000 ohms.
Claim 11
Dependent Claim
16 words
Termination circuit according to claim 1, wherein the pull-up resistor has a resistance of 4,700 ohms.
Claim 12
Dependent Claim
16 words
Termination circuit according to claim 1, wherein the transmission line is a high-speed, hi-directional transmission line.
Claim 13
Dependent Claim
28 words
Termination circuit according to claim 1, wherein: the capacitor, serial resistor and pull-up resistor are physically positioned as close as possible to a connector of the parallel port.
Claim 14
Dependent Claim
111 words
Termination circuit for a transmission line having an end connected to a parallel port, comprising: a serial resistor having a first terminal connected to the, parallel port and a second terminal connected to the end of the transmission line: a null-up resistor having a third terminal connected to the second terminal of the serial resistor and having a fourth terminal; a capacitor having a fifth terminal connected to the first terminal of the serial resistor and having a sixth terminal connected to a ground potential; and a diode having a first terminal connected to the fourth terminal of the pull-up resistor and having it second terminal connected to a supply voltage.
Claim 15
Dependent Claim
111 words
Termination circuit for a transmission line having an end connected to a parallel port, comprising: a serial resistor having a first terminal connected to the, parallel port and a second terminal connected to the end of the transmission line: a null-up resistor having a third terminal connected to the second terminal of the serial resistor and having a fourth terminal; a capacitor having a fifth terminal connected to the first terminal of the serial resistor and having a sixth terminal connected to a ground potential; and a diode having a first terminal connected to the fourth terminal of the pull-up resistor and having it second terminal connected to a supply voltage.
Claim 16
Dependent Claim
20 words
Termination circuit according to claim 13, wherein the fourth terminal, of the pull-up resistor, is connected to a pull-up voltage.
Claim 17
Dependent Claim
25 words
Termination circuit according to claim 13, wherein the serial resistor has a resistance of 22 ohms; and the capacitor has a capacitance of 220 picofarads.
Claim 18
Dependent Claim
16 words
Termination circuit according to claim 15, wherein the pull-up resistor has a resistance of 1,000 ohms.
Claim 19
Dependent Claim
16 words
Termination circuit according to claim 15, wherein the pull-up resistor has a resistance of 4,700 ohms.
Claim 20
Dependent Claim
25 words
Termination circuit according to claim 13, wherein the serial resistor has a resistance of 100 ohms; and the capacitor has a capacitance of 680 picofarads.
Claim 21
Dependent Claim
25 words
Termination circuit according to claim 13, wherein the serial resistor has a resistance of 33 ohms; and the capacitor has a capacitance of 470 picofarads.
Claim 22
Dependent Claim
16 words
Termination circuit according to claim 19, wherein the pull-up resistor has a resistance of 1,000 ohms.
Claim 23
Dependent Claim
16 words
Termination circuit according to claim 19, wherein the pull-up resistor has a resistance of 4,700 ohms.
Claim 24
Dependent Claim
100 words
Method of terminating a transmission line having an end connected to a parallel port having a connector, comprising the steps of: connecting a first terminal of a serial resistor to the parallel port and a second terminal of the serial resistor to the end of the transmission line; connecting a first terminal of a capacitor to the first terminal of the serial resistor and a second terminal of the capacitor to ground; and connecting a first terminal of a pull-up resistor to the end of the transmission line and a second terminal of the pull-up resistor to a supply voltage.
Claim 25
Dependent Claim
100 words
Method of terminating a transmission line having an end connected to a parallel port having a connector, comprising the steps of: connecting a first terminal of a serial resistor to the parallel port and a second terminal of the serial resistor to the end of the transmission line; connecting a first terminal of a capacitor to the first terminal of the serial resistor and a second terminal of the capacitor to ground; and connecting a first terminal of a pull-up resistor to the end of the transmission line and a second terminal of the pull-up resistor to a supply voltage.
Claim 26
Dependent Claim
25 words
Method according to claim 22, further comprising: physically positioning the capacitor and the resistors as close as possible to the connector of the parallel port.
Claim 27
Dependent Claim
18 words
Method according to claim 22, further comprising: connecting a diode between the pull-up resistor and the supply voltage.
Claim 28
Dependent Claim
22 words
Method according to claim 24, and further comprising: connecting a pull-up voltage to a connection of the pull-up resistor and the diode.
Claim 29
Dependent Claim
112 words
Termination circuit for a transmission line having an end and communicating signals with a parallel port, comprising: a serial resistor having a first terminal connected to the parallel port and a second terminal connected to the end of the transmission line; a capacitor having a third terminal connected to the first terminal of the serial resistor and having a fourth terminal connected to a ground potential; a pull-up resistor having a fifth terminal connected to the second terminal of the series resistor and having a sixth terminal; and a diode having a seventh terminal connected to the sixth terminal of the pull-up resistor and an eighth terminal connected to a power supply.
Claim 30
Dependent Claim
112 words
Termination circuit for a transmission line having an end and communicating signals with a parallel port, comprising: a serial resistor having a first terminal connected to the parallel port and a second terminal connected to the end of the transmission line; a capacitor having a third terminal connected to the first terminal of the serial resistor and having a fourth terminal connected to a ground potential; a pull-up resistor having a fifth terminal connected to the second terminal of the series resistor and having a sixth terminal; and a diode having a seventh terminal connected to the sixth terminal of the pull-up resistor and an eighth terminal connected to a power supply.
Claim 31
Dependent Claim
26 words
Termination circuit according to claim 26, wherein: the seventh terminal of the diode is a cathode; and the eighth terminal of the diode is an anode.
Claim 32
Dependent Claim
16 words
Termination circuit according to claim 26, wherein: the transmission line is a high-speed, bi-directional transmission line.
Claim 33
Dependent Claim
112 words
Termination circuit for a transmission line having an end and communicating signals with a parallel port, comprising: a serial resistor having a first terminal connected to the parallel port and a second terminal connected to the end of the transmission line; a capacitor having a third terminal connected to the second terminal of the serial resistor and having a fourth terminal connected to a ground potential; a pull-up resistor having a fifth terminal connected to the second terminal of the series resistor and having a sixth terminal; and a diode having a seventh terminal connected to the sixth terminal of the pull-up resistor and an eighth terminal connected to a power supply.
Claim 34
Dependent Claim
112 words
Termination circuit for a transmission line having an end and communicating signals with a parallel port, comprising: a serial resistor having a first terminal connected to the parallel port and a second terminal connected to the end of the transmission line; a capacitor having a third terminal connected to the second terminal of the serial resistor and having a fourth terminal connected to a ground potential; a pull-up resistor having a fifth terminal connected to the second terminal of the series resistor and having a sixth terminal; and a diode having a seventh terminal connected to the sixth terminal of the pull-up resistor and an eighth terminal connected to a power supply.
Claim 35
Dependent Claim
26 words
Termination circuit according to claim 29, wherein: the seventh terminal of the diode is a cathode; and the eighth terminal of the diode is an anode.
Claim 36
Dependent Claim
16 words
Termination circuit according to claim 29, wherein: the transmission line is a high-speed, hi-directional transmission line.
Claim 37
Dependent Claim
65 words
Method of terminating a transmission line having an end connected to a parallel port having a connector, comprising the steps of: connecting a serial resistor between the parallel port and the transmission line; connecting a capacitor between the parallel port and ground; connecting a pull-up resistor to the end of the transmission line; and connecting a diode between the pull-up resistor and a supply voltage.
Claim 38
Dependent Claim
65 words
Method of terminating a transmission line having an end connected to a parallel port having a connector, comprising the steps of: connecting a serial resistor between the parallel port and the transmission line; connecting a capacitor between the parallel port and ground; connecting a pull-up resistor to the end of the transmission line; and connecting a diode between the pull-up resistor and a supply voltage.
Claim 39
Dependent Claim
22 words
Method according to claim 32, and further comprising: connecting a pull-up voltage to a connection of the pull-up resistor and the diode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-11-10 | 2001-05-12 | 2001-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-10 | 2005-05-12 | 2005-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-10 | 2009-05-12 | 2009-11-11 | $7700.00 | Window Closed / Lapsed |