Electronic digital logic circuitry – Signal sensitivity or transmission integrity – Bus or line termination
Reexamination Certificate
2002-12-16
2004-09-07
Tan, Vibol (Department: 2819)
Electronic digital logic circuitry
Signal sensitivity or transmission integrity
Bus or line termination
C326S086000, C326S083000, C326S026000, C327S108000, C327S065000, C375S288000
Reexamination Certificate
active
06788099
ABSTRACT:
BACKGROUND SECTION
1. Field of the Invention
This invention relates generally to techniques for transferring electronic information, and relates more particularly to a system and method for effectively implementing an active termination circuit in an electronic device.
2. Description of the Background Art
Implementing effective methods for transferring electronic information is a significant consideration for designers and manufacturers of contemporary electronic systems. However, effectively implementing electronic systems may create substantial challenges for system designers. For example, enhanced demands for increased transfer functionality and performance may require additional hardware resources. An increase in hardware requirements may also result in a corresponding detrimental economic impact due to increased production costs and operational inefficiencies.
Furthermore, enhanced system capability to perform various advanced transfer operations may provide additional benefits to a system user, but may also place increased demands on the control and management of various system components. For example, an enhanced electronic system that effectively supports a hard-disk drive may benefit from an efficient implementation because of the large amount and complexity of the digital data involved.
Due to growing demands on system resources and substantially increasing data magnitudes, it is apparent that developing new techniques for implementing and performing transfer operations is a matter of concern for related electronic technologies. Therefore, for all the foregoing reasons, developing effective systems for implementing and transferring electronic information remains a significant consideration for designers, manufacturers, and users of contemporary electronic systems.
SUMMARY
In accordance with the present invention, a system and method are disclosed for effectively implementing an active termination circuit in an electronic device. In one embodiment of the present invention, a source device and a destination device from an electronic system may bi-directionally communicate through a transmission line that includes a conductor A and a conductor B.
The electronic system may perform high-speed data transmissions by simultaneously using both conductor A and conductor B to transfer two corresponding differential data signals in a differential transmission mode. In addition, the electronic system may alternately use conductor A and conductor B to separately transfer individual single-ended signals in a single-ended transmission mode. In accordance with the present invention, at least one active termination circuit may be coupled to conductor A and conductor B, and appropriate control logic may then advantageously cause the active termination circuit to operate in either a differential termination configuration or a single-ended termination configuration to optimize transmissions over conductor A and conductor B.
During the differential transmission mode, current sources of the active termination circuit may be turned on, and the active termination circuit may create a differential mode termination resistance across conductor A and conductor B to effectively terminate the transmission line. The differential mode termination resistance may be selected to match an impedance of the transmission line to thereby optimize transmissions of high-speed differential data in the differential transmission mode.
Furthermore, during the single-ended transmission mode, the current sources of the active termination circuit may be turned off, and the active termination circuit may responsively create high-value single-ended mode termination resistances between conductor A and electrical ground potential, and between conductor B and electrical ground potential, to thereby effectively isolate the separate individual signals transferred over the transmission line by essentially creating an open circuit between conductor A and conductor B.
During a differential/single-ended mode transition procedure, the transmission line may initially be operating in a differential transmission mode to transfer differential signals from a source device to a destination device. The source device may indicate a change of transmission mode by utilizing any appropriate means, and the control logic of the destination device may responsively detect the change of transmission mode in any effective manner. Current sources from the active termination circuit may then be turned off by the control logic in response to detecting the indicated change of transmission mode.
The active termination circuit may dynamically switch from a differential mode termination configuration to a single-ended mode termination configuration in response to the control logic turning off the foregoing current sources. Then, the source device may advantageously transmit single-ended signals over the transmission line to the destination device, in accordance with the present invention.
During a single-ended/differential mode transition procedure, the transmission line may initially be operating in a single-ended transmission mode to transfer separate and individual signals from a source device to a destination device. The source device may indicate a change of transmission mode by utilizing any appropriate means, and the destination device may responsively detect the change of transmission mode in any effective manner. The control logic may then turn on the current sources of the active termination circuit in response to detecting the indicated change of transmission mode.
The active termination circuit may then dynamically switch from a single-ended mode termination configuration to a differential mode termination configuration in response to the control logic turning on the foregoing current sources. The source device may then advantageously transmit corresponding differential signals over the transmission line to the destination device, in accordance with the present invention. The present invention therefore provides an improved a system and method for effectively implementing an active termination circuit in an electronic device.
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Koerner Gregory J.
Simon & Koerner LLP
Sony Corporation
Tan Vibol
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