Impedance matching circuit
DCFirst Claim
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1. An impedance matching circuit comprising:
- a reference impedance;
a comparator having a first input coupled to a terminal of the reference impedance having an output and a second input of the comparator coupled to a constant reference voltage;
a pull-up counter coupled to an output of the comparator;
a pull-up array having a first terminal coupled to a power supply voltage and a second terminal coupled to the terminal of the reference impedance and the first input of the comparator; and
a pull-down array having a first terminal coupled to a ground and a second terminal coupled to the first input of the single comparator.
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Abstract
An impedance matching circuit has a reference impedance. A comparator has a first input coupled to a terminal of the reference impedance and has an output. A pull-up counter is coupled to the output of the single comparator.
184 Citations
13 Claims
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1. An impedance matching circuit comprising:
- a reference impedance;
a comparator having a first input coupled to a terminal of the reference impedance having an output and a second input of the comparator coupled to a constant reference voltage;
a pull-up counter coupled to an output of the comparator;
a pull-up array having a first terminal coupled to a power supply voltage and a second terminal coupled to the terminal of the reference impedance and the first input of the comparator; and
a pull-down array having a first terminal coupled to a ground and a second terminal coupled to the first input of the single comparator. - View Dependent Claims (2, 3, 4)
- a reference impedance;
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5. An impedance matching circuit comprising:
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a reference impedance having a first terminal coupled to a ground; a comparator having a first input coupled to a second terminal of the reference impedance and a second input coupled to a constant reference voltage; a counter/register coupled to an output of the comparator, wherein the counter/register includes a pull-up counter register and a pull-down counter register; and a first switch between the output of the comparator and the pull-up counter register. - View Dependent Claims (6, 7, 8)
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9. An impedance matching input buffer comprising:
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an impedance matching circuit having a reference impedance and a comparator having a constant reference voltage as an input to the comparator; a pull-up array coupled to a pull-down array and an input signal, the pull-up array receiving an impedance matching signal from the impedance matching circuit; and an input buffer having an input coupled to the pull-up array, the pull-down array and the input signal, wherein the impedance matching circuit has a pull-up counter/register coupled to an output of the comparator and a pull-down counter/register coupled to the output of the comparator. - View Dependent Claims (10, 11, 12, 13)
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Specification