Method And System For Mitigating Transformer Saturation In A Communication Interface

摘要

A method and system for mitigating transformer saturation in a communication interface is provided. The method may include detecting a change in impedance resulting from transformer saturation of at least one isolation transformer utilized in a network path of a network. The network may conform to an IEEE 802.3af specification where power may be delivered through the network. The method may further comprise generating a pulse at a one end of the network and measuring a reflection at that end to detect the transformer saturation. In response to the impedance change, a transmitter signal may be pre-distorted in order to compensate for the detected transformer saturation, or the power delivered over the network may be disabled.

主权项

1. A network interface card comprising:
a power supply configured to produce a direct current (DC) power signal; a data transmission circuit configured to receive digital data for transmission over a network cable to a remote location, the data transmission circuit operable to convert the received digital data to a differential voltage; an isolation transformer having a primary winding coupled with the data transmission circuit to receive the differential voltage, a center tap coupled to the power supply to receive the DC power signal, and a secondary winding configured for coupling to the network cable to provide a composite signal to the network cable, the composite signal being a superposition of the DC power signal for powering a device through the network cable and the differential voltage for communicating information to a receiver on the network cable, the isolation transformer having a variable impedance which varies with the DC power signal in the isolation transformer; and a circuit coupled with the data transmission circuit and the isolation transformer and operable to detect variations in the variable impedance of the isolation transformer.