Method and apparatus for independent output driver calibration
AssigneeMicron Technology, Inc.
InventorTerry R. Lee
Life of this patent
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Abstract
An apparatus and method for independently adjusting or calibrating the characteristics of multiple drivers for output buffer circuits without significantly increasing the associated necessary circuitry is disclosed. A central control logic circuit initiates the calibration process of the drivers. A serial communication link is provided between the control logic and each of the output drivers. The serial link reduces the number of lines that are required to communicate between the central control logic and the multiple output drivers. The output drivers can be calibrated one at a time, and a handoff is made from one driver to the next to start the calibration of the subsequent driver.
Claims17
A method for independently calibrating a driver in each of a plurality of buffer circuits, said method comprising:
- providing a control signal from a central control circuit to a driver control circuit associated with a first of said plurality of buffer circuits;
- performing a calibration operation on a driver in said first of said plurality of buffer circuits in response to said control signal;
- providing an output signal from said driver control circuit associated with said first of said plurality of buffer circuits when said calibration operation is complete;
- inputting said output signal into a driver control circuit associated with another of said plurality of buffer circuits;
- and
- performing a calibration operation on a driver in said another of said plurality of buffer circuits in response to said output signal.
A circuit for independently calibrating a driver in each of a plurality of buffer circuits comprising:
- a central control circuit;
- a plurality of serially connected driver control circuits, each of said plurality of driver control circuits associated with said driver in a respective one of said plurality of buffer circuits, each of said driver control circuits having an input and an output, said input of a first of said serially connected driver control circuits being connected to said central control circuit, said output of each of said plurality of driver control circuits being connected to said input of a subsequent driver control circuit;
- a control signal output from said central control circuit to said first of said serially connected driver control circuits, said first driver control circuit in response to said control signal performing a calibration operation on its associated driver, and upon completion of said calibration operation said first driver control circuit providing said control signal at its output to a next subsequent driver control circuit,
- whereby in response to said control signal said next subsequent driver control circuit performs a calibration operation on its associated driver.
Dependencies are inferred from the claim text.