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Current imbalance compensation for magnetics in a wired data telecommunications network

  • US 7,577,104 B2
  • Filed: 12/07/2005
  • Issued: 08/18/2009
  • Est. Priority Date: 11/03/2004
  • Status: Active Grant
First Claim
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1. A method for compensating for an effective current imbalance in a pair of conductors carrying common mode electrical power, the conductors coupled to power sourcing equipment (PSE) and a powered device (PD) via a first magnetic device and a second magnetic device, the first and second magnetic devices each having a primary and secondary winding, the method comprising:

  • sending a signal between the PSE and the PD;

    detecting an effective current imbalance between the PSE and the PD from the signal; and

    applying a direct current bias at a desired point between the PSE and the PD in response to the detected current imbalance, the direct current bias having a magnitude and direction to compensate for the effective current imbalance;

    wherein a receiver circuit is coupled to the pair of conductors carrying the common mode electrical power, the receiver circuit being constructed and arranged to receive the signal between the PSE and the PD;

    wherein a processor circuit is coupled to the receiver circuit;

    wherein detecting the effective current imbalance between the PSE and the PD from the signal includes generating, from the processor circuit, a difference error signal indicating a magnitude of droop present on the first and second magnetic devices based on a comparison between (i) waveform characteristics of the signal, when received by the receiver circuit, and (ii) waveform characteristics of an ideal signal; and

    wherein applying the direct current bias at the desired point between the PSE and the PD in response to the detected current imbalance includes injecting current at an node coupled to the pair of conductors in response to the difference error signal.

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