Output drivers for IC

  • US 6,653,882 B2
  • Filed: 06/11/2002
  • Issued: 11/25/2003
  • Est. Priority Date: 07/31/2001
  • Status: Active Grant
First Claim
Patent Images

1. An output driver for an integrated circuit comprising:

  • a driver circuit for driving an external circuit, the driver circuit having;

    a data input connected to the integrated circuit;

    a data output connected to a transmission line leading to the external circuit; and

    an impedance adjusting means for adjusting the output impedance of the driver circuit according to impedance adjusting data;

    a dummy circuit comprising a dummy driver circuit and a dummy transmission line, the dummy driver circuit and the dummy transmission line being electrical replicas of the driver circuit and the transmission line, respectively; and

    an impedance control circuit for controlling the output impedance of the driver circuit, the impedance control circuit being connected to the dummy circuit and the impedance adjusting means, wherein the impedance control circuit is configured to control the impedance of the driver circuit by determining the impedance adjusting data necessary for matching the output impedance of the dummy driver circuit to the impedance of the dummy transmission line and outputting the determined impedance adjusting data to the impedance adjusting means of the driver circuit, wherein the dummy driver circuit is a scaled down replica of the driver circuit.

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