Impedance Mismatch Detection Circuit
First Claim
1. A comparison circuit for detecting impedance mismatch between pull-up and pull-down devices in a circuit to be monitored, the comparison circuit comprising:
- a comparator operative to receive first and second signals and to generate, as an output of the comparison circuit, a third signal indicative of a difference between the first and second signals;
a first signal generator connected with the first input of the comparator and operative to generate the first signal indicative of a difference between reference pull-up and pull-down currents that is scaled by a prescribed amount, the reference pull-up current being indicative of a current flowing through at least one corresponding pull-up transistor device in the circuit to be monitored, the reference pull-down current being indicative of a current flowing through at least one corresponding pull-down transistor device in the circuit to be monitored; and
a second signal generator connected with the second input of the comparator and operative to generate the second signal as a reference voltage defining a prescribed impedance mismatch threshold associated with the circuit to be monitored.
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Accused Products
Abstract
A comparison circuit for detecting impedance mismatch between pull-up and pull-down devices in a circuit to be monitored includes a comparator operative to receive first and second signals and to generate, as an output, a third signal indicative of a difference between the first and second signals. A first signal generator is operative to generate the first signal indicative of a difference between reference pull-up and pull-down currents that is scaled by a prescribed amount. The reference pull-up current is indicative of a current flowing through at least one corresponding pull-up transistor device in the circuit to be monitored. The pull-down reference current is indicative of a current flowing through at least one corresponding pull-down transistor device in the circuit to be monitored. A second signal generator connected with the second input of the comparator is operative to generate the second signal as a reference voltage defining a prescribed impedance mismatch threshold associated with the circuit to be monitored.
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Citations
20 Claims
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1. A comparison circuit for detecting impedance mismatch between pull-up and pull-down devices in a circuit to be monitored, the comparison circuit comprising:
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a comparator operative to receive first and second signals and to generate, as an output of the comparison circuit, a third signal indicative of a difference between the first and second signals; a first signal generator connected with the first input of the comparator and operative to generate the first signal indicative of a difference between reference pull-up and pull-down currents that is scaled by a prescribed amount, the reference pull-up current being indicative of a current flowing through at least one corresponding pull-up transistor device in the circuit to be monitored, the reference pull-down current being indicative of a current flowing through at least one corresponding pull-down transistor device in the circuit to be monitored; and a second signal generator connected with the second input of the comparator and operative to generate the second signal as a reference voltage defining a prescribed impedance mismatch threshold associated with the circuit to be monitored. - 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 including at least one comparison circuit for detecting impedance mismatch between pull-up and pull-down devices in a circuit to be monitored, the at least one comparison circuit comprising:
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a comparator operative to receive first and second signals and to generate, as an output of the comparison circuit, a third signal indicative of a difference between the first and second signals; a first signal generator connected with the first input of the comparator and operative to generate the first signal indicative of a difference between reference pull-up and pull-down currents that is scaled by a prescribed amount, the reference pull-up current being indicative of a current flowing through at least one corresponding pull-up transistor device in the circuit to be monitored, the reference pull-down current being indicative of a current flowing through at least one corresponding pull-down transistor device in the circuit to be monitored; and a second signal generator connected with the second input of the comparator and operative to generate the second signal as a reference voltage defining a prescribed impedance mismatch threshold associated with the circuit to be monitored.
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20. An electronic system, comprising:
at least one integrated circuit, the at least one integrated circuit including at least one comparison circuit for detecting impedance mismatch between pull-up and pull-down devices in a circuit to be monitored, the at least one comparison circuit comprising; a comparator operative to receive first and second signals and to generate, as an output of the comparison circuit, a third signal indicative of a difference between the first and second signals; a first signal generator connected with the first input of the comparator and operative to generate the first signal indicative of a difference between reference pull-up and pull-down currents that is scaled by a prescribed amount, the reference pull-up current being indicative of a current flowing through at least one corresponding pull-up transistor device in the circuit to be monitored, the reference pull-down current being indicative of a current flowing through at least one corresponding pull-down transistor device in the circuit to be monitored; and a second signal generator connected with the second input of the comparator and operative to generate the second signal as a reference voltage defining a prescribed impedance mismatch threshold associated with the circuit to be monitored.
Specification