Impedance adjustment circuits and methods using replicas of variable impedance circuits
First Claim
1. An impedance adjustment circuit for controlling an impedance of a variable impedance circuit, the comprising:
- a calibration circuit including a replica of the variable impedance circuit and configured to generate an impedance control signal for the variable impedance circuit based on a voltage generated at the replica of the variable impedance circuit in response to a reference current.
1 Assignment
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Accused Products
Abstract
An impedance adjustment circuit for controlling an impedance of a variable impedance circuit includes a calibration circuit including a replica of the variable impedance circuit and configured to generate an impedance control signal for the variable impedance circuit based on a voltage generated at the replica of the variable impedance circuit in response to a reference current. The calibration circuit may be configured to generate the reference current based on a reference resistor coupled thereto. In particular, the calibration circuit may be configured to match a current in the replica of the variable impedance circuit and a current in the reference resistor to generate the voltage at the replica of the variable impedance circuit.
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Citations
33 Claims
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1. An impedance adjustment circuit for controlling an impedance of a variable impedance circuit, the comprising:
a calibration circuit including a replica of the variable impedance circuit and configured to generate an impedance control signal for the variable impedance circuit based on a voltage generated at the replica of the variable impedance circuit in response to a reference current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An integrated circuit device comprising:
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a variable impedance pull-down circuit and a variable impedance pull-up circuit coupled to an external signal node;
a first calibration circuit configured to generate respective first and second impedance control signals for the variable impedance pull-down and pull-up circuits;
a second calibration circuit configured to generate respective third and fourth impedance control signals for the variable impedance pull-down and pull-up circuits; and
a selection circuit configured to receive the first, second, third and fourth impedance control signals, to apply the first and third impedance control signals to the respective variable impedance pull-up and pull-down circuits in response to a first state of a selection control signal, and to apply the second and fourth impedance control signals to the respective variable impedance pull-up and pull-down circuits in response to a second state of the selection control signal. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A method of controlling an impedance of a variable impedance circuit, the method comprising:
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generating a voltage at a replica of the variable impedance circuit in response to a reference current; and
generating an impedance control signal for the variable impedance circuit based on the voltage at the replica of the variable impedance circuit. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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Specification