Current mode driver with variable termination
AssigneeIntel Corporation
InventorsAaron K. Martin, Bryan K. Casper, Stephen R. Mooney
Life of this patent
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Abstract
A simultaneous bidirectional port circuit includes a current mode output driver for driving an output node and a current mode return driver for driving a differential receiver. Variable impedance termination devices are included to provide terminations for both the current mode output driver and current mode return driver. A control circuit and method set the impedance value of the variable impedance termination devices by comparing voltage values at the output of the current mode output driver and current mode return driver.
Claims30
A method comprising:
- transmitting a first current signal to a parallel combination of a first termination impedance and a transmission line;
- transmitting a second current signal to a second termination impedance;
- comparing a first voltage on the first termination impedance to a second voltage on the second termination impedance;
- and
- modifying the first termination impedance.
An article comprising a machine-readable medium with instructions encoded thereon, the instructions when executed operable to cause a computerized system to perform:
- turning off a first current driver coupled to a transmission line;
- turning on a second current driver coupled to the transmission line;
- comparing a voltage on an output node of the second current driver to a second voltage;
- and
- modifying a termination impedance on the output node of the second current driver.
An integrated circuit comprising:
- a first differential current driver having an output node;
- a first variable impedance termination device coupled to the output node of the first differential current driver;
- a second differential current driver having an output node;
- a comparator coupled to the output nodes of the first and second differential current drivers;
- and
- a control circuit to modify the first variable impedance termination device responsive to the comparator.
An electronic system comprising:
- a pair of conductors;
- a first integrated circuit including a first current mode driver having a differential output node coupled to a first end of the pair of conductors, a first pair of variable impedance termination devices coupled to the differential output node of the first current mode driver, a second current mode driver having a differential output node, a comparator having input nodes coupled to the differential output nodes of the first and second current mode drivers, and a control circuit to influence the first pair of variable impedance termination devices responsive to the comparator;
- and
- a second integrated circuit having a third current mode driver coupled to a second end of the pair of conductors.
Dependencies are inferred from the claim text.