Patent ID: 6020732
Filing Date: 2000-02-01
Classification: H04M

Abstract:
A transformer line circuit comprising:a transformer having a primary winding and a secondary winding, the primary winding receiving both a direct current from a single power supply and an alternating current signal and the secondary winding transferring the alternating current signal to an external secondary circuit; anda flux cancelling circuit connected to the transformer that forms only one single current path in the transformer that passes current from the primary winding directly through the secondary winding and then through the flux cancelling circuit back to the primary winding, the flux cancelling circuit allowing the same internal direct current in that same single current path to pass through the primary and secondary winding in a manner such that a magnetic flux created in the primary winding from the internal direct current in that same single current path is cancelled by an equal amount of flux produced by the same internal direct current flowing through that same single current path in the secondary winding without using a compensation current generated from any external compensation circuit,the same flux cancelling circuit filtering the alternating current while allowing the magnetic flux generated by the alternating current to pass through the transformer from the primary winding to the secondary winding through that same single current path.