US 7,548,823 B2Granted

Correction of delay-based metric measurements using delay circuits having differing metric sensitivities

AssigneeInternational Business Machines Corporation

InventorsHarmander Singh, Alan J. Drake, Fadi H. Gebara, John P. Keane, Jeremy D. Schaub, Robert M. Senger

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Abstract

Correction of delay-based metric measurements using delay circuits having differing metric sensitivities provides improved accuracy for environmental and other circuit metric measurements that used delay lines. A delay line measurement, which may be a one-shot measurement or a ring oscillator frequency measurement is performed either simultaneously or sequentially using at least two delay lines that have differing sensitivities to a particular metric under measurement. A correction circuit or algorithm uses the measured delays or ring oscillator frequencies and corrects at least one of the metric measurements determined from one of the delays or ring oscillator frequencies in conformity with the other delay or ring oscillator frequency. The delays may be inverter chains, with one chain having a higher sensitivity to supply voltage than the other delay chain, with the other delay chain having a higher sensitivity to temperature. Temperature results can then be corrected for supply voltage variation and vice-versa.

Claims14

Dependent claims

A method for determining a first value of a first circuit metric under measurement and a second value of a second circuit metric under measurement within an integrated circuit, comprising:

measuring a first time delay or oscillation frequency of a first circuit;
measuring a second time delay or oscillation frequency of a second circuit, wherein a predetermined first sensitivity of the first time delay or oscillation frequency of the first circuit to the first circuit metric under measurement differs from a predetermined second sensitivity of the second time delay or oscillation frequency of the second circuit to the first circuit metric under measurement, wherein a predetermined third sensitivity of the first time delay or oscillation frequency of the first circuit to a second circuit metric under measurement differs from a predetermined fourth sensitivity of the second time delay or oscillation frequency of the second circuit to the second circuit metric under measurement;
determining the first value of the first circuit metric under measurement from of the first time delay or oscillation frequency the second time delay or oscillation frequency, the first sensitivity and the second sensitivity;
and
determining the second value of the second circuit metric under measurement from of the first time delay or oscillation frequency, the second time delay or oscillation frequency, the third sensitivity and the fourth sensitivity.

2 more elements

Dependencies are inferred from the claim text.