Non-invasive power supply tester
First Claim
1. A power supply tester wherein the improvement comprises:
- a voltmeter circuit that can sense the voltage across a preexisting conducting element of a power supply under test, said voltage being proportional to the output current of said power supply under test by an operational resistance of unknown value, and generate electrical signals quantifying said voltage,a current injector circuit that can force quantified fluctuations in said output current of said power supply under test,a first means for user input that allows the user of said power supply tester to control the amplitude and waveform of said output current fluctuations, and to define the test to be performed,a second means for user output that makes measurement results available to the user of said power supply tester, anda third means for control that provides memory, computational, and control functions according to a predetermined algorithm that includes collecting data and calculation of output current, said third means being electrically interfaced to said voltmeter circuit, said current injector circuit, said first means, and said second means,whereby said output current of said power supply under test is measured without any prerequisite design constraint on, or alteration of said power supply under test.
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Accused Products
Abstract
The output current of a switching regulator in operation on a printed circuit board can be accurately measured without opening the circuit, and without specially dedicated sensing components in the regulator. The inherent series resistance of an inductor or similar resistive component can be used—even though it'"'"'s resistance and its temperature are unknown. The apparatus is easily extended to make other measurements such as transient response and output impedance. These measurements are generally easier to perform and more convenient than other commonly used methods. Key elements are an injector circuit (312), a voltmeter circuit (310), a control unit with arithmetic capability (316), a user input unit (324) and a user output unit (326).
27 Citations
9 Claims
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1. A power supply tester wherein the improvement comprises:
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a voltmeter circuit that can sense the voltage across a preexisting conducting element of a power supply under test, said voltage being proportional to the output current of said power supply under test by an operational resistance of unknown value, and generate electrical signals quantifying said voltage, a current injector circuit that can force quantified fluctuations in said output current of said power supply under test, a first means for user input that allows the user of said power supply tester to control the amplitude and waveform of said output current fluctuations, and to define the test to be performed, a second means for user output that makes measurement results available to the user of said power supply tester, and a third means for control that provides memory, computational, and control functions according to a predetermined algorithm that includes collecting data and calculation of output current, said third means being electrically interfaced to said voltmeter circuit, said current injector circuit, said first means, and said second means, whereby said output current of said power supply under test is measured without any prerequisite design constraint on, or alteration of said power supply under test. - View Dependent Claims (2, 3, 4, 5)
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6. A power supply test method comprising:
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measuring the voltage drop across a component of a power supply under test, said component being one that is conducting the output current of said power supply under test, and said component being one that is preexisting in said power supply under test, and the resistance of said component being unknown, forcing a predetermined change in said output current of said power supply under test, calculating the value of said output current of said power supply under test by solving a set of linear equations involving multiple measurements of said DC voltage drop, and measurement requirements information obtained through a first means for user input, and making said value of output current available to the user through a second means for user output, whereby said output current is measured without requiring any prerequisite design constraint on, or temporary alteration of said power supply under test. - View Dependent Claims (7)
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8. A power supply tester wherein the improvement comprises:
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an alternating current voltmeter circuit that can measure the frequency-selective alternating current fluctuations of the output voltage of the power supply under test, an alternating current injector circuit can generate alternating current fluctuations in the output current of the power supply under test, said alternating current fluctuations being of known amplitude and frequency content, and without requiring alteration of said power supply under test, a first means for user input that allows the user of said power supply tester to control the amplitude and waveform of said output current fluctuations, and to define the test to be performed, a second means for user output that makes measurement results available to the user of said power supply tester, and a third means for control that provides memory, computational, and control functions according to a predetermined algorithm that includes collecting data and calculation of output impedance, said third means being electrically interconnected to said voltmeter circuit, said current injector circuit, said first means, and said second means, whereby said output impedance of said power supply under test is measured at a plurality of frequencies, without requiring any prerequisite design constraint on, or alteration of said power supply under test. - View Dependent Claims (9)
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Specification