• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 29 subscribers
  • Views 711 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8323R: SHx inputs completely blown up

Thibault Lestavel1
Prodigy 60 points
Part Number: DRV8323R

Hi,

My design is a DRV8323RS centered design with a µcontroller supporting SPI communication and I/O driving.

I'm using the internal buck to generate a 5V (which is enabled but no significant current is drawn in the problem I'm facing).

The schematic is based on datasheets' information for a 1-sense resistor control:

I'm hooking a 24V power supply and a 150W 24V brushless DC motor phase to my board.

It worked fine during a few days of playing but now I had two nasty blow ups:

We can easily spot the inputs 9 and 16 (SHA and SHB) completely burned out.

It happened at least once during chip SPI reprogramming; could chip configuration/re-configuration lead to this behavior? What could?

Thanks,

Tibo

  • 0
    TI__Guru 61380 points

    Tibo,

    Please let me know your IDRIVE settings.

    On the damaged device, have you compared the gate to source resistance for all three phases?

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    TI__Guru 61380 points

    Tibo,

    Which registers were you changing when the chip was damaged?

    Have you checked if the back EMF is spiking excessively when the motor is loaded, braked hard, etc? Maybe the output voltage is spiking and causing the SHx node to be damaged.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 60 points

    Hi Adam,

    1) Regarding the register setting, we kept the default ones. Meaning driving current was set to 1000mA while, by calculation, we should have had less than 130mA. 

    We will update the register settings and give it another try.

    Faulty Re-calculated
    DRV CTRL 0x0040 0x00C0
    GATE HS 0x03FF 0x0322
    GATE LS 0x07FF 0x0722
    OCP CTRL 0x015F 0x02C3
    CSA CTRL 0x0283 0x021C

    Do you think it can come from this mis-configuration?

    2) I measured both "good" and "blown up" mosfet gate-source resistors on the board:

    OK NOK
    HSU 480k 3.5M
    LSU 148k 75k
    HSV 480k 30R
    LSV 148k 15R
    HSW 480k 300R
    LSW 148k 0R

    I desoldered the LSW mosfet, on-board measurement still shows 0R while the mosfet itself have >1M impedance.

    3) Actually, registers were not changed during motor spinning (wrong assumption on my side)

    4) We haven't checked the back EMF spikes, that will be the next step after register update. Nevertheless, current motor is not loaded at all.

    We used to play a lot with the BoostXL board (with the same - wrong - register parameters) and haven't had any problem...

    Any thoughts?

    Thanks!

  • 0 in reply to Thibault Lestavel1
    TI__Guru 61380 points

    Thibault,

    Having the IDRIVE too high will cause the issue you describe above. You can check the FAQ I have posted here:

    https://e2e.ti.com/support/motor-drivers/f/38/t/796378

    Regards,

    -Adam