Output drivers for IC
First Claim
1. An output driver for integrated circuits 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 an 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.
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Accused Products
Abstract
The invention features an output driver for integrated circuits that includes a driver that has a data input connected to the integrated circuit, a data output connected to a transmission line leading to the external circuit, and impedance adjusting means for adjusting the output impedance of the driver circuit according to determinable impedance adjusting data. The output driver also includes a dummy circuit having a dummy driver circuit and transmission line, and an impedance control circuit for controlling the output impedance of the driver circuit. The impedance control circuit controls 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 characteristic impedance of the dummy transmission line and outputting the determined impedance adjusting data to the impedance adjusting means of the driver circuit.
11 Citations
10 Claims
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1. An output driver for integrated circuits comprising:
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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 an 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for controlling the output impedance of an integrated circuit, the method comprising:
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providing the integrated circuit comprising a driver circuit for driving an external circuit, the driver circuit having;
a data input connectable to the integrated circuit;
a data output connectable 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 determinable impedance adjusting data;
determining the impedance adjusting data necessary for matching the output impedance of a dummy driver circuit to the characteristic impedance of a dummy transmission line, the dummy driver circuit and the dummy transmission line being electrical replica of the driver circuit and of the transmission line, respectively; and
outputting the determined impedance adjusting data to the impedance adjusting means of the driver circuit to match the output impedance of the driver circuit to the characteristic impedance of the transmission line.
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Specification