US Patent 7327156 LSI testing apparatus for testing an electronic device

AN LSI testing apparatus includes a power source unit for supplying the direct source current to an electronic device, a detecting unit for detecting the source current supplied to the electronic device and a judging unit for judging the quality of the electronic device, wherein the power source unit includes a unit for overlaying overlaid signals with a predetermined period on the source current, and the judging unit judges the quality of the electronic device on the basis of the source current detected by the detecting unit in case the electronic device is supplied with the source voltage on which the overlaid signals are overlaid.