Current Feedback Configuration; Temperature Measured With Ntc On Board - Infineon EVAL-M7-HVMOS-INV User Manual

EVAL-M7-HVMOS-INV user guide
Evaluation power board with M7 connector
System and functional description
Figure 9 Bus voltage feedback
2.3.3

Current feedback configuration

There are two current feedback configurations on this EVAL-M7-HVMOS-INV power board. One is a single-shunt
current feedback configuration. The other is a leg-shunt current feedback configuration. The single shunt
configuration is the default setting on the board. If users want to use a leg-shunt configuration, they should
remove the resistors R26, R27, and R27 first. Then they should solder the resistors R29, R30, R31, RS2, and RS3.
The value is 0 Ω for R29, R30, and R30. RS2 and RS3 are 75 mΩ. Please refer to the schematics for more details in
Chapter 3.
Figure 10 shows the single-shunt current-sensing circuit. According to the explanation in MCEWizard for Question
83, the current input scaling can be calculated as:
�������������� ���������� �������������� = ��
And the offset voltage calculated is:
�������� =
EVAL-M7-HVMOS-INV
Figure 10 Current sensing – single shunt
2.3.4

Temperature measured with NTC on board

In order to measure the case temperature of the MOSFET switch, an NTC was assembled on the board near the
U-phase, low-side MOSFET. The NTC was placed on the board as shown in Figure 11. It is very close to MOSFET
with glue. But there is a little gap between the NTC and MOSFET case. So there will be a difference between the
measured case temperature and real MOSFET case temperature. The pull-up resistor on the EVAL-M7-D111T
control board is 4.87 kΩ. The connection between the NTC and control board is shown in Figure 11. According to
the NTC datasheet, Table 8 gives the NTC resistance values at intermediate temperature in case users want to
calculate the divider voltage.
User guide
��12
× ���� =
������
��15 + ��12
R15
× ������ =
R15 + R12 2 + 22.1
15 of 30
22.1
× ����2 =
2 + 22.1
2
× 5 = 0.415 �� = 415 ����
× 75 = 68.8 ����/��
EVAL-M7-D111T
Revision 1.0
2021-06-28