Cisco Technology, Inc.

Meilissa R Lum

Roger Antoine Karam

Kan-Chiu Seto

Mehran Ataee

Jim C Chiappe

Dean Wood

An improved method is performed within power-sourcing equipment. The method controls delivery of power to a remotely powerable device through a communications pathway that connects the power-sourcing equipment to the remotely powerable device. The method involves obtaining an initial resistance value representing an initial resistance of the communications pathway, and obtaining an operating resistance value representing an operating resistance of the communications pathway after obtaining the initial resistance value. The method further involves generating a temperature change result based on the initial resistance value and the operating resistance value, and selectively one of enabling, scaling back and disabling delivery of power to the remotely powerable device through the communications pathway based on the temperature change result.

Techniques for controlling delivery of power to a remotely powerable device based on temperature

Methods and apparatus are disclosed for balancing power across all conductors of an Ethernet connection. Balancing circuitry is disclosed to allow an Ethernet midspan device to receive power from an Ethernet Power Sourcing Equipment (PSE) on the signal pairs of an Ethernet connection. The balancing circuitry is configured to sense the level of the received power, and generate a second power source substantially equal to the received power level. The received power is provided to an Ethernet Powered Device (PD) over the signal pairs of an Ethernet connection, and the generated power to the PD over the unused pairs of the Ethernet connection.

Method and apparatus for current sharing ethernet power across four conductor pairs using a midspan device

A powered device, such as an IP telephone, includes power converter electronics that allows the powered device to couple to multiple power sources and receive a relatively large amount of power (e.g., 15 W or greater) from any single power source or from any combination of the power sources. For example, the powered device can connect to a first power source and a second power source by a cable having four twisted pairs of conductors where a first two-pair set of conductors couples the powered device to the first power source and a second two-pair set of conductors couples the powered device to the second powered device. In use, the converter circuitry can provide power to the load from either the first power source via the first two-pair set of conductors, the second power source via the second two-pair set of conductors, or from both power sources via both the first and second two-pair sets of conductors.

Method and apparatus distributing power to a load in a powered device

A common mode termination includes a shielded connector, a receive section and a transmit section, each section comprising an isolation transformer, a common mode transformer, a reference autotransformer, and an AC shield return. Each transmit section reference autotransformer and receive section reference autotransformer has a center tap for the application of a bias voltage and a bias voltage return. The bias voltage is fed through a common mode transformer, and the resultant common mode termination reduces the conduction of EMI from the serdes coupled to the common mode termination to cables connected to the connector. This common mode termination also provides a reference termination for the copper twisted pair cable and reduces resonances on the cable. Finally, this termination also provides filtering on the DC power source wires and improves noise immunity from transients coupled onto the twisted pair cable into the system.

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San Jose, CA, United States of America

Meilissa R Lum