EVAL-IH-R5IPB-A-V1 Evaluation board
User Guide
Usage
(a)
(b)
(c)
(d)
Figure 7
Assembling a device onto the heatsink and the PCB
Assembling process is easier than disassembling. Figure 7 presents a possible sequence of steps:
1.
Prepare the TO package by cutting the leads to a length of around 5 mm (a).
2.
Bend the pins 3 and 5 towards the front of the package in order to provide an offset of roughly 3.5 mm with
respect the other pins (a).
3.
Put a sufficient amount of thermal grease on the insulator material in order to guarantee a good thermal
contact.
4.
Place the package on the heatsink making sure that it lays perfectly flat on the surface of the heatsink (b).
5.
Put the spring clip on the package and heatsink groove, and fasten it using pliers (c).
6.
Solder one lead after the other on the top side of the PCB (d).
4.1.2
Tuning collector-emitter voltage sense network
The IEWS20R5135IPB features an over-voltage protection functionality that prevents the V
CE
voltage to exceed
defined values. It also prevents the device from turning on if V
CE
is higher than a determined threshold. The
behavior of the over-voltage protection is determined by the voltage at the VDET pin, and can be adjusted by
modifying this voltage value. The evaluation boards implement a resistor chain to supply the voltage at VDET
pin, as shown in Figure 8a. The resistor RVDET can be replaced in order to change the voltage at VDET. Figure 8b
shows the relation of the resistance RVDET and the corresponding value of the limiting voltage. When the V
CE
exceeds the limiting voltage, the IEWS20R5135IPB switches to over-voltage shutdown (INN voltage is pulled to 0
V). In this mode, the device can actively clamp the voltage in order to prevent it from exceeding the maximum V
CE
of the IGBT. The over-voltage shutdown mode is deactivated as soon as VVDET falls below a restart threshold
1
,
with a minimum blanking time of 3 ms. Figure 8a also shows that a second resistor chain is derived from the main
resistor dividers. This chain is used to provide the information from the V
CE
to the MCU, so that it can determine
when the IGBT has to be turned on. The usage of a shared chain for sensing VVDET and for triggering the the turn-
on of the IGBT is a cheaper and less space-consuming solution compared to a solution with two distinct resistor
divider chains.
Figure 8c shows a reference of how the VVDET should look in comparison to V
CE
voltage. As can be seen in the
picture, the voltage at VDET and the voltage V
CE
show the same behavior except for a small shift in time that is
caused by the capacitance between VDET and GND. In general, the parasitic capacitance that is present at the
package level between the heatsink and VDET pin has to be considered in addition to the external capacitance
2
.
1
For a detailed explanation of the clamping behavior refer to the application note of the IPD [1].
2
Please note that in this board the heatsink is connected to GND for safety reasons. In industrial designs the heatsink is usually at the
same potential as the collector of the IGBT. As a consequence, the effect of the parasitic capacitance between VDET and the heatsink
Application Note
11 of 34
V 1.1
2019-11-25