The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 2001
Filed:
Aug. 11, 1999
Masaru Yamagishi, Tokyo, JP;
Ando Electric Co., Ltd., Tokyo, JP;
Abstract
A tester detects an abnormality in a quiescent power supply current of a device under test. In the tester, a programmable voltage generation source controls a power supply unit, providing a device under test with power. A test pattern generator applies test patterns repeatedly to the device under test. Power supply current to the device under test is converted into voltage values by a detection resistor. A spectrum analyzer unit finds a differential between voltage values occurring between opposite ends of the detection resistor, and voltage values proportional to power supply current values of a device known to perform properly, as measured beforehand. The spectrum analyzer ouputs a power of a fundamental wave of a frequency spectrum obtained by applying the EFT method to the differential. The decision unit prestores spectrum reference values Po as the maximum values for power of the fundamental wave, giving a decision that the quiescent power supply current is abnormal if the power is in excess of the spectrum reference value. The decision is sent out to a CPU, and displayed on a display unit.