Delay variability reduction method and apparatus
AssigneeSun Microsystems, Inc.
InventorAninda Roy
Life of this patent
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Abstract
A method for reducing delay variability in a differential receiver includes receiving a plurality of differential input signals, determining a first transition delay time of an output in response to the plurality of differential input signals, determining a second transition delay time of the output in response to the plurality of differential input signals, and modifying capacitance coupled to the output in response to the first transition delay time and to the second transition delay time.
Claims20
A method for reducing delay variability in a differential receiver comprises:
- receiving a plurality of differential input signals;
- determining a first transition delay time of an output in response to the plurality of differential input signals, the first transition delay time associated with a rising signal bias of the differential receiver;
- determining a second transition delay time of the output in response to the plurality of differential input signals, the second transition delay time associated with a falling signal bias of the differential receiver;
- and
- modifying capacitance coupled to the output in response to the first transition delay time and to the second transition delay time.
A method for configuring a differential amplifier comprises:
- varying an amount of capacitance coupled to the differential amplifier;
- for each amount of capacitance coupled to the differential amplifier, determining an associated delay variability factor of the differential amplifier, wherein the associated delay variability factor is associated with a bias selected from a group comprising:
- rising transition bias, falling transition bias;
- determining a target amount of capacitance, the target amount of capacitance having an associated delay variability factor lower than other associated delay variability factors;
- and
- coupling the target amount of capacitance to the differential amplifier.
An apparatus for amplifying differential signals comprises:
- a differential amplifier having differential outputs;
- a series of controllable switches coupled to the differential outputs of the differential amplifier;
- a series of capacitors coupled to the series of controllable switches;
- and
- state machine coupled to the differential outputs and to the series of controllable switches, the state machine configured to vary an amount of capacitance coupled to the differential outputs by controlling the controllable switches, wherein the state machine is also configured to determine an associated delay variability factor of the differential amplifier for each capacitance coupled to the differential outputs, and wherein the state machine is configured to determine a target amount of capacitance, the target amount of capacitance having an associated delay variability factor lower than other associated delay variability factors.
Dependencies are inferred from the claim text.