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UCC5390: UCC5390SCDR using bipolar supply

Part Number: UCC5390

Hi, 

Good day.

Our customer wants to know if UCC5390SC can be used with bipolar power supply. They are using it with Vcc2 +18V and Vee2 at -6Vand they told me that it seems to work fine. Now they want to know if it is okay to continue running without chip failure. Please advise. 

Thank you in advance.


Regards,


Cedrick

  • Hi, Cedrick,

    The E version of the UCC5390 is designed for this use case. If they have a resistor between OUTH and OUTL (eg, not tied directly together), the S version will work. The drawback is the UVLO on the VCC2 supply will be referenced to -VEE2 instead of ground. So, if they want UVLO protection, they should change to the S version.

    If this answered your question, please press the green button. Let me know if you have any further questions.

  • Hello Don, 

    Thank you for your response. It really helps us. 

    One last question. You have mentioned about a resistor between OUTH and OUTL. Do you have a recommended value for it? Would a 1 ohm resistor be sufficient for this? 

    I'd appreciate your support. 

    Thank you and have a great day!


    Regards,
    Cedrick

  • Hi Cedrick,

    The resistor that Don has mentioned is the gate resistor. He means that there is a resistor for OUTH to connect to the gate of the MOSFET/IGBT and a second one to connect from OUTL to the MOSFET/IGBT. OUTH and OUTL should not be tied directly together. Please see figure 57 in the datasheet. The resistance is chosen based on the desired drive strength to turn on/off the MOSFET/IGBT. Please see this application note and this guide regarding gate resistor choice.

    Regards,

    Audrey