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DRV8350R: DRV8350R damaged after high current

Peter Mirtschink
Prodigy 220 points
Part Number: DRV8350R
Other Parts Discussed in Thread: CSD18511KTT, DRV8350

Dear all,

we have build an BLDC controller arround DRV8350R and CSD18511KTT like in the DRV8350-EVAL Kit. Motor turn good. We work on 18V and use 5,2 Ah batterie.

If we now got to higher torque values, meassurement in batterie line show approx. 50 Ampere, after one or two times the DRV8350R is damaged. PCB is hot but not 170 °C.

We use as I-Drive HW setting with 1 Ampere. Any idea what can be the problem?

Normaly we stop with fast ramp down and then brake, in lower values it work good. In higher values the IC stop automatically (PWM an other are active). After this stop the IC is damaged.

Can it help to reduce I-Drive? We have try 300 mA but problem is not fixed, maybe lower? We will use TSC-Diodes from SHA, SHB, SHC to GND?

Regards,

Peter

  • 0
    TI__Guru 63690 points

    Peter,

    The CSD18511KTT FET has very low Qgd of 9.7 which means that this FET only needs 100mA to switch at the very fast speed of 100nS. Do you have a switch node rise/fall time requirement?

    Even 300mA is way too fast to switch this FET and you will likely see oscillation and ringing on the gate and source nodes. This is what is causing the driver failure. 

    Please lower the IDRIVE to the lowest setting and check if the performance is quick enough for you. 

    We have a guide on this here: https://e2e.ti.com/support/motor-drivers/f/38/t/796378

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 220 points

    Hi Adam,

    thank you for your fast reply. We will repair our boards and try with the lowest value. I will came back if this resolve the problem or not.

    Regards,

    Peter

    --> Edit:

    We have set the current to lowest value and it seems to work. We have try 6 hours and don't get any problem. Thank you very much.

    Maybe you can edit the datasheet of DRV8350 and insert a line in which is recomend to set the current for 100 ns - 300 ns?

  • 0 in reply to Peter Mirtschink
    TI__Guru 63690 points

    Peter,

    We try our best to explain this :)

    If your issue has been resolved, please help us out by clicking the green “This Resolved My Issue” button.

    If you have a related question, please use the orange "Ask a related question" in the top right corner of the page.

    Regards,

     -Adam