Apparatus and method for reducing crosstalk in an integrated circuit which includes a signal bus
AssigneeIntel Corporation
InventorMaynard Falconer
Life of this patent
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Abstract
An apparatus and method to compensate for variations in effective electrical impedance of a digital bus having plurality of transmission lines in a very large scale integrated circuit includes bus driver circuitry, which comprises a plurality of transistors coupled to an output node that is connected to a corresponding one of the transmission lines. Control circuitry is utilized to selectively enable/disable the transistors, thereby adjusting the driver impedance of the bus driver circuitry so as to match a state of the digital bus.
Claims13
A method for driving a digital bus that includes a plurality of closely coupled lines, the method comprising the steps of:
- (a) accessing a particular impedance state of the digital bus;
- and
- (b) adjusting an output impedance of a bus driver circuit to match cross-talk induced impedance associated with the particular impedance state of the digital bus, the bus driver circuit being coupled to a respective line of the digital bus.
An integrated circuit for reduced cross-talk, comprising:
- a digital bus having a plurality of coupled transmission lines, a transmission line having an effective electrical impedance that depends on a particular bus state;
- a bus driver comprising a plurality of transistors coupled to an output node which is connected to the transmission line of the digital bus;
- control circuitry that selectively enables/disables each of the transistors to create a transistor combination that produces an impedance at the output node that matches the effective electrical impedance associated with the particular bus state.
Apparatus for driving a digital bus having a plurality of transmission lines comprising:
- a plurality of bus driver circuits, each of which has an output coupled to a corresponding one of the transmission lines;
- multiplexer circuitry to access a particular state of the digital bus;
- and
- a plurality of resistors coupled to the bus driver circuits to dynamically adjust a driver impedance of each of the bus driver circuits so as to match the cross-talk
- induced impedance associated with the particular state of the digital bus.
Dependencies are inferred from the claim text.