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1. 发明专利

JPH07174814A ELEMENT TESTING METHOD 失效
公开(公告)号：JPH07174814A
公开(公告)日：1995-07-14
申请号：JP34467993
申请日：1993-12-21
申请人： SONY TEKTRONIX CORP
发明人： KATO KATSUHISA , ONOZAWA TOSHIHIKO , EBISAWA AKIRA , USUDA KOICHI
IPC分类号： G01R31/26
摘要： PURPOSE:To check whether there is abnormality or not and efficiently carry out a characteristic test by applying right bias voltage to an element to be tested and detecting the current prior to a characteristic test of the element to be tested. CONSTITUTION:Each terminal of an insulated gate bipolar transistor(IGBT) 10, which is an element to be tested, is set so as to be brought into contact with a terminal of a testing apparatus. Under the control of a processing apparatus 52, a gate bias voltage generating circuit 32 and a collector voltage source 36 generate voltage respectively, so that slight collector current can flow in the case the IGBT 10 is normal. The collector current flows in a resistor 34 and an ADC (A/D converter) 46 supplies digital signals to the apparatus 52. The apparatus 52 determines that the IGBT 10 is short-circuited when the short-circuited collector current at the time short circuit occurs between the collector and the emitter of the IGBT 10 is almost the same as the actual collector current and determines that the circuit is opened at the time the actual collector current does not flow practically. That is, it is determined that the element to be tested has a defect.

2. 发明专利

JPH07174813A ELEMENT TESTING METHOD 失效
公开(公告)号：JPH07174813A
公开(公告)日：1995-07-14
申请号：JP34467893
申请日：1993-12-21
申请人： SONY TEKTRONIX CORP
发明人： KATO KATSUHISA , ONOZAWA TOSHIHIKO , EBISAWA AKIRA , USUDA KOICHI
IPC分类号： G01R31/26
摘要： PURPOSE:To recognize the contact condition of terminals of an element to be tested, and surely carry out a characteristic test by applying prescribed voltage to terminals for a signal channel and testing whether the detected voltage is the prescribed voltage or not. CONSTITUTION:Each terminal of an insulated gate bipolar transistor(IGBT) 10, an element to be tested, is so put as to be brought into contact with a terminal of a testing apparatus. Electric continuity of an emitter fourth terminal (a terminal for a signal channel) 22 and a gate return terminal 26 is checked. In a processing apparatus 52, a voltage generating circuit 32 supplied prescribed voltage to the terminal 26 and at the same time, a differential amplifier 44 controls as to amplify only the voltage of an input terminal connected to the terminal 22 of a resistor 34. When the value computed from the output signal of an ADC (A/D converter) 46 corresponds to the prescribed voltage supplied to the terminal 26, the terminals 26, 22 are electrically continued. When the value does not corresponds to the voltage, they are not electrically continued and the abnormality is displayed. Successively, following the processing procedure stored in the apparatus 52, prior testing is carried out to check the contact condition of each terminal of the IGBT 10 with each corresponding terminal.

3. 发明专利

JPH0843478A CHARACTERISTIC MEASURING METHOD FOR POWER-DEVICE CIRCUIT 失效
公开(公告)号：JPH0843478A
公开(公告)日：1996-02-16
申请号：JP19604894
申请日：1994-07-28
申请人： SONY TEKTRONIX CORP
发明人： KATO KATSUHISA , EBISAWA AKIRA , USUDA KOICHI
IPC分类号： G01R31/26 , H01L21/66
摘要： PURPOSE:To measure the parameter of an IGBT circuit with good accuracy. CONSTITUTION:An IGBT is set to an OFF state, and electric power is supplied to a diode (Step 50). A collector current from the diode is detected by using a resistance (Step 52). The output signal of a resistor is sampled, and a plurality of pieces of diqital data age generated (Step 54). A gradient straight line due to the inductive load of the collector current is computed on the basis of the plurality of pieces of digital data by using the method of least squares (Step 56). Then, when the difference between the peak of the collector current and the gradient straight line at its point of time is computed, the recovery current of the diode can be computed (Step 58).

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