Detection method of Infineon IGBT module
I. Discrimination of Infineon igbt module field effect tube with pointer multimeter
(1) Discrimination of electrode of Infineon IGBT module junction field effect transistor by resistance measurement method
According to the phenomenon that the forward and reverse resistance values of the PN junction of the field effect tube are different, the three electrodes of the junction type field effect tube can be identified. Specific method: Dial the multimeter to R × 1k, and select two electrodes, and measure the forward and reverse resistance values respectively. When the forward and reverse resistance values of two electrodes are equal and are several thousand ohms, the two electrodes are the drain D and the source S, respectively. Because for the junction FET, the drain and source are interchangeable, the remaining electrode must be the gate G. You can also touch the black test lead (the red test lead of the multimeter) to one electrode at will, and the other test lead to contact the other two electrodes in order to measure the resistance value. When the resistance values measured twice are approximately equal, the electrode contacted by the black test lead is the gate electrode, and the remaining two electrodes are the drain electrode and the source electrode, respectively. If the resistance values measured twice are very large, it means that the PN junction is reversed, that is, they are reverse resistances. It can be judged that they are N-channel field effect transistors, and the black test lead is connected to the gate. The resistance values are very small, indicating that it is the forward PN junction, that is, the forward resistance, which is determined to be a P-channel field effect transistor, and the black test lead is also connected to the gate. If the above situation does not occur, the black and red test leads can be replaced and tested according to the above method until the grid is identified.
(2) Judging the quality of Infineon's IGBT module field-effect transistor with the resistance measurement method
The resistance measurement method uses a multimeter to measure the resistance between the source and drain of the FET, the gate and source, the gate and drain, and the gate G1 and G2. Whether it is consistent or not to judge the quality of the tube. Specific method: First set the multimeter to R × 10 or R × 100, and measure the resistance between the source S and the drain D, usually in the range of tens of ohms to thousands of ohms (as can be seen in the manual, various models The resistance value of the tube is different), if the measured resistance value is greater than the normal value, it may be due to poor internal contact; if the measured resistance value is infinite, it may be an internal disconnection. Then put the multimeter in the R × 10k range, and then measure the resistance between the gates G1 and G2, between the gate and the source, and between the gate and the drain. When the resistance values are measured to be infinite, then It indicates that the tube is normal; if the above resistance values are too small or are channels, it means that the tube is bad. It should be noted that if the two grids are broken in the tube, the component replacement method can be used for detection.
Several detection methods of three electrodes of Infineon IGBT module(3) Estimation of Infineon's IGBT Module Amplification Ability by Inductive Signal Input Method
Specific method: Use R × 100 of multimeter resistance, connect red test lead to source S, black test lead to drain D, and apply 1.5V power supply voltage to the field effect tube. At this time, the resistance between the drain and source indicated by the meter needle value. Then, hold the grid G of the junction field effect transistor by hand, and add the induced voltage signal of the human body to the grid. In this way, due to the amplification effect of the tube, both the drain-source voltage VDS and the drain current Ib must be changed, that is, the resistance between the drain-source has changed, and thus the watch hand can be observed to have a large swing. If the pin of the grid pin is small, it means that the tube has a poor magnifying ability; if the pin is big, it means that the tube has a large magnifying ability; if the pin does not move, the tube is broken.
According to the above method, we use the R × 100 range of the multimeter to measure the junction field effect tube 3DJ2F. First open the G-pole of the tube, and measure the drain-source resistance RDS to be 600Ω. After pinching the G-pole with your hand, the meter will swing to the left, the indicated resistance RDS will be 12kΩ, and the range of the meter will be larger, indicating that the tube is good. , And has a larger magnification ability.
Several detection methods of three electrodes of Infineon IGBT moduleWhen using this method, a few points need to be explained: First, when testing the FET to hold the grid with your hand, the multimeter needle may swing to the right (resistance value decreases) or to the left (increased resistance value). This is because the AC voltage induced by the human body is high, and the operating point of different field effect tubes when measured with a resistance file may be different (either in the saturated region or in the unsaturated region). Experiments show that the RDS of most tubes increases That is, the hand is swinging to the left; the RDS of a few tubes is reduced, which makes the hand to swing to the right. However, regardless of the direction of the hand's swing, as long as the hand's swing is large, it means that the tube has a large magnification ability. Second, this method is also applicable to MOS FETs. However, it should be noted that the input resistance of the MOS field effect transistor is high, and the induced voltage allowed by the grid G should not be too high, so do not directly pinch the grid with your hand. It must be used to hold the insulating handle of a screwdriver and touch it with a metal rod. Touch the grid to prevent the body's induced charge from directly adding to the grid and causing grid breakdown. Third, each measurement should be shorted between GS electrodes. This is because the GS junction capacitor will be charged with a small amount of charge, which establishes the VGS voltage, which may cause the hands to move when the measurement is performed again. It is only necessary to discharge the short-circuited charge between the GS electrodes.
Several detection methods of three electrodes of Infineon IGBT module
(4) Discrimination of Infineon IGBT module unlabeled field effect tube by resistance measurement methodFirst, use the method of measuring resistance to find two pins with resistance value, that is, source S and drain D, and the remaining two pins are ** gate G1 and second gate G2. Record the resistance value between the source S and the drain D measured with two test leads first, and then measure the test leads again, and then record the measured resistance values. Measure the resistance with a larger value twice, black test leads. The electrode connected is the drain D; the red test lead is connected to the source S. The S and D poles identified by this method can also be verified by estimating the magnification ability of the tube, that is, the black test pen with large magnification is connected to the D pole; the red test pen is grounded to 8 poles. The test results of all methods should be the same. After the positions of the drain D and source S are determined, the circuit is installed according to the corresponding positions of D and S. Generally, G1 and G2 will also be aligned in order. This determines the positions of the two gates G1 and G2. Thus, the order of the D, S, G1, and G2 pins is determined.
(5) Judging the size of transconductance by measuring the change in reverse resistance
When measuring the transconductance performance of a VMOSN channel enhanced field effect transistor, a red test lead can be connected to the source S and a black test lead can be connected to the drain D, which is equivalent to adding a reverse voltage between the source and the drain. At this time, the grid is open and the reverse resistance of the tube is very unstable. Select the ohm range of the multimeter in the high resistance range of R × 10kΩ. At this time, the voltage in the meter is higher. When you touch the grid G with your hand, you will find that the reverse resistance value of the tube changes significantly. The larger the change, the higher the transconductance value of the tube; if the transconductance of the tube under test is small, use this method to measure At this time, the reverse resistance does not change much.