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TIDA-00778: change IGBT to NMOSFETs in parallel

Intellectual 915 points

Replies: 15

Views: 1209

Part Number: TIDA-00778

Dear TI Experts:

I have a targeted application (rated 3KW, Vbus=86V for a 3 phase PMSM control ). I found TIDA-00778 is a powerful design.

Now I hope to apply the following UCC27714 gate driver design to drive NMOSFETs, instead of a IGBT. 

The spec. of the NMOSFET I found is VDS=200V, RDS=10.7 mOhm, and ID=88A.  Also, I will apply parallel operation of power MOSFETs (I will arrange 3 NMOSFETs in parallel. It is 5 FETs in parallel in TIDA-00364)

Since UCC27714 is much more powerful than UCC27211 (in TIDA-00364), is it feasible to apply the following gate driver design to drive NMOSFETs in parallel?

Could you kindly reply me?

Wish you the best!

Tang Han

  • In reply to user4008740:

    Hi Tang,

    Yes, you are right. You have to tune the resistor values when you change the supply from 15V to 12V. Also, as discussed previously, you have tune the gate resistors based on the MOSFET you have used. Please refer the TI designs TIDA-00472 or TIDA-00778 or the datasheet of UCC27714 for design calculations.

    Regards,

    Manu

  • In reply to Manu Balakrishnan:

    Dear Manu:

    1. I am sorry that I hope to find an AEC-Q100 Qualified gate drive to replace UCC27714. Could you kindly suggest a suitable one? 

    I only find a similar one UCC27712-Q1 with smaller sink and source current than UCC27714.  Do you think it is a good one for my targeted application (Vbus=86V rated 3KW) (3 MOSFETs in parallel as I previouly mentioned)?

    2. For UCC27712-Q1, I found its circuit, provided by datasheet (shown below) is so simple.  I can't even find the gate resistor.  Is it due to AEC-Q100 Qualified? So it is more powerful?  Or in fact, the circuit can't be so simple!  Is there any practical circuit for reference?

    3. Could I ask about the heat problem in the Inverter circuit? As you know, in the TIDA-00364, the design uses 'Insulated Metal Substrate PCB'  and SMD MOSFETs for better cooling, which requires a lot of surface.

    Recently I found an automative grade MOSFET (VDS=150V, RDS=4.8mOhm, ID=171A), which is not SMD MOSFET. Its datasheet shows how to screw the heat sink, which seems much easier than that in TIDA-00364.  Does it really work in practical application?  Does it mean the automative grade MOSFET have better ability of heat dissipation?

    I am sorry to consult you a lot again.  Could you kindly take your time to reply me?

    Wish you the best and happy forever!

    Tang Han

  • In reply to user4008740:

    Hi Tang,

    Please see my comments below.

    1. Decision on using single UCC27712-Q1 for  driving multiple MOSFETs depends on the total gate charge of all MOSFET together. I would suggest you to calculate the best switching turn on time and off time with the maximum gate current from UCC27712-Q1 and decide on whether the 1.8A source current is good enough. I would suggest you to read more on gate drive design aspects with any standard material.

    2. Please refer the application and implementation section of the datasheet to find the application circuit. You will find the gate resistors there. A similar circuit of TIDA-00364 should work.

    3. The MOSFET heat dissipation depends on the its thermal resistance, which should be given in the datasheet. From my understanding, we CANNOT say that an automotive component have a better heat dissipation. There are so many materials available on the MOSFET thermal dissipation calculation and heat sink connection. I would suggest you to study any standard material and do design based on the parameters given in the datasheet.

    Since this thread is started a couple of weeks back, it may get locked out soon. I hope, I brought some clarity and explanation to your questions to execute your design. If so let me know if it is resolved and if we can close this thread. You will always be able to open a new thread if you have further questions.

    Thanks & Regards,

    Manu

  • In reply to Manu Balakrishnan:

    Dear Manu:

    Thanks for yor instant and professional reply. You are so kind to me.
    Yes, you have given me a lot of clarity and explanation to my questions to execute my design.

    May you have a prosperous New Year!
    Tang Han
  • In reply to user4008740:

    Thank Manu for his kind and professional suggestion and help!!! ^_^

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