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User’s Guide
HB2637L-EVK-301
© 2022 ROHM Co., Ltd.
No. 65UG002E Rev.001
Apr. 2022
Figure 5: Top view of the board with LED locations
3.3 Isolated Power Supply and setting the gate drive voltage
The isolated power supply is realized with a simple half bridge converter which operates at a constant switching frequency of
100kHz and 50% duty cycle. Positive and negative drive voltages that are necessary for high side and low side devices are
generated from this isolated power supply.
3.3.1 Adjusting the positive drive voltage
A simple open loop control has been implemented for the isolated power supply generation. Hence to adjust the positive drive
voltage the input supply on the CO1 has to be adjusted accordingly.
The recommended gate source voltage of ROHM SiC MOSFET SCT4036KW is 15-18V. However, driving with 18V proves to be
more efficient.
For a gate drive voltage of 18V approximately 15.5V is necessary at the connector CO1. Gate drive voltages lower than 16V are
not possible because the undervoltage lock out level the gate driver used BM61S41RFV-C lies at 15.5V.
3.3.2 Adjusting the negative drive voltage
Some SiC MOSFETs might require a negative gate turn off voltage and for some a 0V turn off is enough. The recommended turn
off voltage of SCT4036KW7 is 0V.
However, to provide flexibility for the user to test the SiC MOSFET SCT4036KW7 with negative gate voltages, jumpers have been
provided to adjust between 0V turn off and negative gate turn off.
5V Supply
HS Supply
LS Supply
