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UCC5310: Using UCC5310 as an isolated load switch

Part Number: UCC5310

Hi,

I am developing low cost precharger solution for a solar inverter. The switch for this precharger is an IGBT. I was wondering if I can use the UCC531x or any other isolated gate driver to turn on and off the IGBT in this case. 

Thanks,

Carlos 

  • Hi  Carlos,

    The UCC53x0 family is used to drive IGBTs and MOSFETs. The family is differentiated by different current ratings and features such as split outputs, miller clamp, and UVLO referenced to the GND2 pin.

    Take a look at the datasheet and let me know if one of these solutions works for your design. 

    Regards,

    Mateo

  • Hello Mateo,

    Why would I want those different differentiations (split output, miller clamp and UVLO)? What is the difference between them? Do they turn on different transistors? And the most important question, what would be the best option to turn on an IGBT and to function as a load switch.

    Thanks,

    Carlos
  • Hi Carlos,

    The spit-output option, UCC5320S and UCC5390S, have separate pins for the pull-up and pull-down circuits. They are used to adjust the rise and fall times of the gate driver with separate resistors rather than have a resistor in parallel with another resistor and a schottky diode.

    The miller clamp option, UCC5310M and UCC5350M, have a clamp pin that will prevent unwanted turn-on due to large dV/dt.

    The UVLO pin option, UCC5320E and UCC5390E, have a GND2 pin used is to reference the output side supply to the source of the IGBT.

    Can you provide a schematic of the system? There are a few considerations to take into account in order to decide which flavor is best.

    Regards,
    Mateo
  • Mateo,

    Attached you will find my circuit application. This is a precharger circuit that will charge a DC link capacitor to avoid inrush current due to discharged capacitors. I would like to use an IGBT or MOSFET to act as a load switch and let pass the initial inrush current. The "control system" circuit would be a switch comprised of an isolated load switch and a microcontroller or interface.

    Thanks,

    Carlos

  • Hi Carlos,

    Yes, the UCC5310 can be used as you have shown in your application.

    Is there a reason you chose an IGBT? What is the voltage rating of the battery that you are using?

    regards,
    Mateo

  • Hi Mateo,

    It can be an IGBT or a MOSFET, depending on the voltage. We are targeting a 400V battery and IGBTs have the rating and they are cheaper than a MOSFET at a higher voltage range. I have a question, how can I spec for the power supply? How much power (current wise) do I have to supply to the UCC chip? Since this is providing 2,3,4 or even 10 Amps in certain chips, I imagine the caps provide this charge and not the power supply, is that right? 

    Thanks,

    Carlos

  • Hi Carlos,

    Thank you for explaining your use of an IGBT, I agree that it would be a good fit here.

    Yes, the output capacitors carry the burden of supplying the current.

    Regards,
    Mateo