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DRV8323: DRV8323 HOT!!!

kelvin.liu
Prodigy 30 points
Part Number: DRV8323

Hi,I encounter some issue that the temperature above chip is very high when I use DRV8323 to develop our product. Some details as follow:

testing condition:

35.2 Volts,25 Celsius air tempreture indoor.

MOSFET: IRF7759L2PbF.

Switiching Frequency is 40KHz.

testing data:

50.0 Celsius with MOS closing.

 up to 100.0 Celsius with MOS opening,and still heating.

Who can give mea solution?THKS! 

  • 0
    Prodigy 30 points

    schematic and layout:

  • 0 in reply to kelvin.liu
    TI__Mastermind 26606 points

    Hi Kelvin Liu,

    Thank you for posting your question on the MD forum!

    I reviewed your schematic and have a few questions/comments.

    1. I noticed the power label attached to VM is 48V. You had mentioned the driver being operated at 35.2V. Is that because you chose not to supply 48V?
    2. I would recommend increasing the CPH-CPL and the VM capacitor voltage ratings to around 100V instead of 50V, especially if you are using a 48V supply. This is because the effective capacitance decreases when the capacitor is operated near the voltage rating of the capacitor. We recommend using a capacitor that is rated for 2x VM.
    3. If you are using 48V for VM then that is probably too high of a voltage for this particular gate driver. It is not uncommon for the system to see 1.5 to 2 times the voltage supplied at VM due to things such as switching and back EMF. This particular driver is rated for 60V, and a 48V VM could result in the device seeing 75V or more at times. If this is the case then I would recommend switching to a 100V gate driver option instead.
    4. I would recommend adding a capacitor from VM to PGND that is equal to or greater than 10uF with a voltage rating of about 2x VM (as specified in the datasheet)
    5. Does the MOSFETs get hot during operation, or is it just the gate driver?

    Regards,

    Anthony Lodi

  • 0 in reply to Anthony Lodi
    Prodigy 30 points

    Hi Anthony,

    Thank you!Here are my reply:

    1.our system is designed for a large operating voltage,from 24V to 48V,35.2V is just a testing case.

    2.I have added a new test of 22V,but it is still hot,the tempreture is up to 95.0 Celsius in 2min.

    3.This is a nice advice,Thanks very much!

    4.I have added two 4.7uF capcitors in parallel, with 50V rating,during my testing.

    5.MOSFETs are cold!

    What should I do to rescue my board?

    Hope your reply,THKS!

  • 0 in reply to kelvin.liu
    TI__Mastermind 26606 points

    Hi Kelvin Liu,

    Thank you for your response and the additional information!
    1. I wouldn’t recommend operating the device above a VM of 35V. If you need to use a higher voltage than I would switch to a 100V rated gate driver.
    2. What is your iDrive setting for the device?
    3. Would you be able to send me a scope plot showing of the high side MOSFET VGS as well as the corresponding phase output?
    4. Do you notice any performance issues as the DRV heats up?
    5. Is there any faults recorded during operation?
    6. Regarding the 2 parallel 4.7uF capacitors, did you add those capacitors to the VM-PGND pin? If so I would increase that capacitance to make it above 10uF.
    7. As mentioned before, I would make sure the capacitor voltage ratings are 2x the max voltage that will be applied.

    Regards,

    Anthony