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US 6,480,798 B2Granted
Method and apparatus for independent output driver calibration
AssigneeMicron Technology, Inc.
InventorTerry R. Lee
Life of this patent
Estimating the term…
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.
Claims163
A method for independently calibrating a driver in each of a plurality of buffer circuits, said method comprising:
- providing a first control signal from a central control circuit to a first driver control circuit associated with a first of said plurality of buffer circuits;
- performing a first calibration operation on a first driver in said first of said plurality of buffer circuits in response to said control signal;
- providing an first output signal from said first driver control circuit associated with said first of said plurality of buffer circuits when said first calibration operation is complete;
- inputting said first output signal into a second driver control circuit associated with a second of said plurality of buffer circuits;
- and
- performing a second calibration operation on a second driver in said second of said plurality of buffer circuits in response to said output signal;
- wherein said first and second calibrations each comprise the steps of,
- utilizing a compare circuit to compare an output of a driver being calibrated to a reference signal to provide a respective result;
- inputting said respective result to said central control circuit;
- providing an adjust signal from said central control circuit to a driver control circuit of said driver being calibrated, said adjust signal being based on said result;
- and
- adjusting said output of said driver being calibrated in response to said adjust signal.
9 more elements
A method for calibrating each of a plurality of buffer circuits in an integrated circuit, said method comprising:
- providing a control signal from a central control circuit to a plurality of driver control circuits, each of said plurality of driver control circuits being associated with a respective one of said plurality of buffer circuits, each of said respective driver control circuits having an associated driver;
- and
- independently performing, in response to said control signal, a calibration operation on a driver in each of said plurality of buffer circuits.
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,
- a compare circuit having an output, a plurality of signal inputs and a reference input, said output being connected to said central control circuit, said plurality of signal inputs each being respectively connected to an output of said driver in each of said plurality of buffer circuits;
- a reference signal connected to said reference input of said compare circuit;
- and
- an adjust line for carrying an adjust signal to each of said plurality of buffer circuits,
- whereby in response to said control signal said next subsequent driver control circuit performs a calibration operation on its associated driver;
- and
- whereby said calibration operation is performed by comparing said output of said driver to said reference signal to obtain a result, inputting said result to said central control circuit, and outputting an adjust signal from said central control circuit to a respective one of said plurality of driver control circuits.
7 more elements
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,
- a plurality of compare circuits, each of said plurality of compare circuits having an output, a first input connected to an output of said driver associated with said respective one of said plurality of driver control circuits, and a second input;
- a reference signal connected to said second input of said each of said plurality of compare circuits;
- whereby in response to said control signal said next subsequent driver control circuit performs a calibration operation on its associated driver;
- and
- whereby said calibration operation is performed by comparing said output of said driver to said reference signal to obtain a result, passing said result through said buffer to said central control circuit, and outputting an adjust signal from said central control circuit to said respective one of said plurality of driver control circuits.
5 more elements
A circuit for independently calibrating a driver in each of a plurality of buffer circuits comprising:
- a central control circuit having an output;
- and
- a plurality of driver control circuits, each of said plurality of driver control circuits being associated with said driver in a respective one of said plurality of buffer circuits, each of said plurality of driver control circuits being connected to said output of said central control circuit,
- whereby in response to a control signal from said output of said central control circuit, said driver in each of said buffer circuits is independently calibrated by its associated driver control circuit.
1 more element
An integrated circuit comprising:
- a plurality of buffer circuits, each of said plurality of buffer circuits including an associated driver;
- a calibration circuit for independently calibrating said associated driver of each of said buffer circuits, said calibration circuit comprising:
- a central control circuit;
- a plurality of serially connected driver control circuits, each of said plurality of driver control circuits associated with a driver of each 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.
3 more elements
An integrated circuit comprising:
- a plurality of buffer circuits, each of said plurality of buffer circuits including an associated driver;
- a calibration circuit for independently calibrating said associated driver of each of said buffer circuits, said calibration circuit comprising:
- a central control circuit having an output;
- and
- a plurality of driver control circuits, each of said plurality of driver control circuits being associated with said driver in a respective one of said plurality of buffer circuits, each of said plurality of driver control circuits being connected to said output of said central control circuit,
- whereby in response to a control signal from said output of said central control circuit, said driver in each of said buffer circuits is independently calibrated by its associated driver control circuit.
3 more elements
A processing system comprising:
- a processing device which processes data;
- an integrated circuit connected to said processing device,
- wherein at least one of said processing device and said integrated circuit comprises:
- a plurality of buffer circuits, each of said plurality of buffer circuits including an associated driver;
- a calibration circuit for independently calibrating said associated driver of each of said buffer circuits, said calibration circuit comprising:
- a central control circuit;
- a plurality of serially connected driver control circuits, each of said plurality of driver control circuits associated with a driver of each 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.
6 more elements
The processing system according to 116, wherein in response to said adjust signal, said respective one of said plurality of driver control circuits is adapted to increase and decrease a relative size of at least one transistor in its associated driver.
The processing system according to 116, wherein in response to said adjust signal, said respective one of said plurality of driver control circuits is adapted to increase and decrease an output current of at least one transistor in its associated driver.
The processing system according to 116, wherein in response to said adjust signal, said respective one of said plurality of driver control circuits is adapted to increase and decrease an output voltage of at least one transistor in its associated driver.
The processing system according to 107, wherein said integrated circuit includes said calibration circuit for independently calibrating said associated driver of each of said buffer circuits.
A processing system comprising:
- a processing device which processes data;
- an integrated circuit connected to said processing device,
- wherein at least one of said processing device and said integrated circuit comprises:
- a plurality of buffer circuits, each of said plurality of buffer circuits including an associated driver;
- a calibration circuit for independently calibrating said associated driver of each of said buffer circuits, said calibration circuit comprising:
- a central control circuit having an output;
- and
- a plurality of driver control circuits, each of said plurality of driver control circuits being associated with said driver in a respective one of said plurality of buffer circuits, each of said plurality of driver control circuits being connected to said output of said central control circuit,
- whereby in response to a control signal from said output of said central control circuit, said driver in each of said buffer circuits is independently calibrated by its associated driver control circuit.
6 more elements
The processing system according to 135, wherein said integrated circuit includes said calibration circuit for independently calibrating said associated driver of each of said buffer circuits.
Dependencies are inferred from the claim text.