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US 7,256,617 B2Granted
Method and apparatus to linearize output buffer and on-chip termination
AssigneeSun Microsystems, Inc.
InventorsPriya Ananthanarayanan, Samudyatha Suryanarayana
Life of this patent
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Abstract
A driver circuit that outputs a data signal uses feedback of the data signal to the driver circuit to modulate a drive strength of the driver circuit. The driver circuit has a pull-up driver stage and a pull-down driver stage. The pull-up driver stage uses a pull-up control circuit to modulate a drive strength of the pull-up driver stage dependent on a voltage of the data signal. The pull-down driver stage uses a pull-down control circuit to modulate a drive strength of the pull-down driver stage dependent on the voltage of the data signal.
Claims13
A communication system, comprising:
- a pull-up driver portion arranged to generate a first transition on a data signal, the pull-up driver portion comprising:
- at least one pull-up device operatively connected to the data signal, and pull-up control circuitry arranged to modulate a drive strength of the pull-up device dependent on a feedback of the data signal to the pull-up control circuitry;
- and
- a pull-down driver portion arranged to generate a second transition on the data signal, the pull-down driver portion comprising:
- at least one pull-down device operatively connected to the data signal, and
- pull-down control circuitry arranged to modulate a drive strength of the pull-down device dependent on a feedback of the data signal to the pull-down control circuitry,
- wherein at least one of:
- the pull-up control circuitry is arranged to form a voltage potential divider at an input to the pull-up device dependent on the first transition;
- and
- the pull-down control circuitry is arranged to form a voltage potential divider at an input to the pull-down device dependent on the second transition.
7 more elements
A communication system, comprising:
- a pull-up driver portion arranged to generate a first transition on a data signal, the pull-up driver portion comprising:
- at least one pull-up device operatively connected to the data signal, and
- pull-up control circuitry arranged to modulate a drive strength of the pull-up device dependent on a feedback of the data signal to the pull-up control circuitry;
- and
- a pull-down driver portion arranged to generate a second transition on the data signal, the pull-down driver portion comprising:
- at least one pull-down device operatively connected to the data signal, and
- pull-down control circuitry arranged to modulate a drive strength of the pull-down device dependent on a feedback of the data signal to the pull-down control circuitry,
- wherein at least one of:
- the pull-up driver portion further comprises a diode-connected pull-up device arranged to compensate for current through the pull-up device during a portion of the first transition;
- and
- the pull-down driver portion further comprises a diode-connected pull-down device arranged to compensate for current through the pull-down device during a portion of the second transition.
8 more elements
A method for handling a data signal, comprising:
- receiving data;
- establishing a voltage divider potential dependent on the data signal and the data;
- when the data represents a logic high, pulling up a voltage of the data signal, wherein the pulling up comprises:
- feeding back the data signal, and
- modulating the pulling up dependent on the feeding back;
- and
- when the data represents a logic low, pulling down the voltage of the data signal, wherein the pulling down comprises:
- feeding back the data signal, and
- modulating the pulling down dependent on the feeding back.
6 more elements
A communication system, comprising:
- means for receiving input data;
- means for pulling up a voltage of a data signal when the input data is a logic high, wherein the means for pulling up comprises:
- first control means for controlling a drive strength of the means for pulling up dependent on a feedback of the data signal to the first control means;
- and
- means for pulling down the voltage of the data signal when the input data is a logic low, wherein the means for pulling down comprises:
- second control means for controlling a drive strength of the means for pulling down dependent on a feedback of the data signal to the second control means.
- where in at least one of:
- the first control means comprises means for establishing a voltage divider potential dependent on the data signal and the input data, wherein the drive strength of the means for pulling up is dependent on the voltage divider potential;
- and
- the second control means comprises means for establishing a voltage divider potential dependent on the data signal and the input data, wherein the drive strength of the means for pulling down is dependent on the voltage divider potential.
7 more elements
Dependencies are inferred from the claim text.