Automatic ranging apparatus and method for precise integrated circuit current measurements
First Claim
1. A method of measuring DC current drawn by an integrated circuit, the method comprising:
- coupling the integrated circuit to a computer-based test apparatus which has a plurality of current measurement ranges;
maintaining a software look-up table in a memory which includes an entry indicating a maximum current value for each of the plurality of measurement ranges;
initializing the computer-based test apparatus to a selected measurement range in the plurality of measurement ranges;
measuring the DC current drawn by the integrated circuit with the computer-based test apparatus in the selected measurement range;
comparing the measured DC current to the maximum current value entry in the look-up table for the selected measurement range;
incrementing the selected measurement range if the measured DC current is out of the selected measurement range, based on the comparison; and
repeating the steps of measuring and incrementing until the measured DC current is in the selected measurement range.
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Accused Products
Abstract
A computer-based test method and apparatus for measuring DC current drawn by an integrated circuit. The apparatus has a plurality of current measurement ranges and is first initialized to a selected one of the measurement ranges. Next, the apparatus measures the DC current drawn by the integrated circuit in the selected measurement range and increments the selected measurement range if the measured DC current is out of the selected measurement range. The apparatus repeats the steps of measuring and incrementing until the measured DC current is in the selected measurement range. The measured DC current is then compared to a specification limit for the integrated circuit.
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Citations
16 Claims
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1. A method of measuring DC current drawn by an integrated circuit, the method comprising:
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coupling the integrated circuit to a computer-based test apparatus which has a plurality of current measurement ranges; maintaining a software look-up table in a memory which includes an entry indicating a maximum current value for each of the plurality of measurement ranges; initializing the computer-based test apparatus to a selected measurement range in the plurality of measurement ranges; measuring the DC current drawn by the integrated circuit with the computer-based test apparatus in the selected measurement range; comparing the measured DC current to the maximum current value entry in the look-up table for the selected measurement range; incrementing the selected measurement range if the measured DC current is out of the selected measurement range, based on the comparison; and repeating the steps of measuring and incrementing until the measured DC current is in the selected measurement range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer-based DC current test apparatus comprising:
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a test head having a receptacle for electrically coupling to an integrated circuit; a DC current measurement circuit electrically coupled to the test head and having a plurality of measurement ranges; a processor electrically coupled to the DC current measurement circuit; a storage device electrically coupled to the processor; and software means stored in the storage device and operative on the processor for; maintaining a software look-up table in the storage device which includes an entry for each of the plurality of measurement ranges, each entry specifying the maximum current level in that measurement range; and initializing the DC current measurement circuit to a selected measurement range in the plurality of measurement ranges; measuring the DC current drawn by the integrated circuit with the DC current measurement circuit in the selected measurement range; comparing the measured DC current to the maximum current level specified in the look-up table for the selected measurement range; incrementing the selected measurement range if the measured DC current is out of the selected measurement range, based on the step of comparing; and repeating the steps of measuring, comparing and incrementing until the measured DC current is in the selected measurement range. - View Dependent Claims (10, 11, 12, 13)
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14. A computerized method of measuring DC current drawn by an integrated circuit, the method comprising:
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coupling the integrated circuit to a computer-based test apparatus which has a plurality of current measurement ranges; initializing the computer-based test apparatus to a selected measurement range, which is the lowest measurement range in the plurality of measurement ranges, through a software program that is operable on the computer-based test apparatus; measuring the DC current drawn by the integrated circuit with the computer-based test apparatus in the selected measurement range; generating a range signal indicative of whether the measured DC current is in or out of the selected measurement range; detecting the range signal with the software program; responsively logging the measured DC current through the software program if the range signal indicates the measured DC current is in the selected measurement range; responsively incrementing the selected measurement range through the software program if the range signal indicates the measured DC current is out of the selected measurement range; repeating the steps of measuring, generating and incrementing through the software program until the measured DC current is in the selected measurement range; comparing the logged, measured DC current to a specification limit for the integrated circuit through the software program with the computer-based test apparatus; and generating an output signal indicative of the comparison. - View Dependent Claims (15, 16)
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Specification