Hitachi IGBT Module Application Manual
6.5
Precautions against electrostatic failure
Because the IGBT has a MOS gate structure, you should always take the following precautions as
measures to avoid generating static electricity.
a)
b)
Before starting operation, do not remove the conductive sponge or tape mounted
between gate and emitter.
When handling the IGBT module, ground your body via a high-value resistor
(between 100 Kilohm and 1 Megohm), hold the package body, and do not touch the
gate terminal.
Be sure to ground any parts which the IGBT module may touch, such as the work
table or soldering iron.
Before testing or inspection, be sure to check that any residual electric charge in the
measuring instruments has been removed. Apply voltage to each terminal starting at
0V and return voltage to 0V when finishing.
c)
d)
6.6
IGBT Module Circuit Arrangement and Wiring Method
Arrange the IGBT module as close to the power source as possible. Because excessive voltage applied to
the IGBT module will result in device breakdown, remember to keep the cable between the gate circuit and
IGBT module as short as possible. If this is not done, gate voltage will rise or fall more slowly and the
switching time will become longer.
If the cable between the power source and the IGBT module becomes too long, cable inductance will
generate an overshoot voltage, especially when the module is turned OFF. In addition, the likelihood of noise
generation will be increased. Alternatively, to prevent a long gate cable from experiencing noise easily, either
two-wire stranded cable or shielded cable should be used.
6.7
Measurement Precautions
a)
Before beginning V
CES
measurements, be sure to short-circuit the signal gate and
emitter terminals.
Note:
If the signal gate and emitter terminals are kept open or their
contact is defective during measurement, the IGBT module may be
damaged.
b)
Within the IGBT module, a cable is laid between the chip in the module and the
external connection terminal. The voltage applied to the chip and the voltage of the
external terminal are not identical, especially during switching.
For expressing the time rate of change in current as di/dt and the cable inductance as
L, an inductive voltage equal to L di/dt will be generated within the cable. Typically,
cable inductance L is about 20 to 40 nH. so when the IGBT module is turned ON,
the external terminal voltage observed is higher than the voltage applied to chip.
Conversely, when the IGBT module is turned OFF, the observed external terminal
voltage is lower than the voltage applied to the chip.
c)
The voltage applied to the chip should not be permitted to exceed the rated voltage
of the device.
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