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RE: DRV8350: DRV8350 Issue at high load current

user3771213
Prodigy 60 points
Other Parts Discussed in Thread: DRV8350

We test the controller with DRV8350RSRGZR and we can load the current to 100A, but still have 2 issues for it, Could you give some suggestion? Thank you very much!

 1. The low side gate driver fail, fail phenomenon is that one or two pin of GLA(Pin 10), GLB(Pin15), GLC(Pin20), SLA(Pin11), SLB(Pin14), SLC(Pin21) resistance will drop to 0.7M ohm, It will fail when start the motor with heavy load status. The resistance is above 10M ohm for the OK gate driver.

2. The VCP(Pin 7) voltage is not enough. the VCP(Pin 7) voltage will drop to 4V when heavy load dyno test, We use default setting of the gate driver. Duo to can't find some register to config the data. I guess that it should be configured the output voltage and charging time to adjust the drive capability.

  • 0
    TI__Guru 65430 points

    Wilson,

    I split this post to a new thread as the previous issue is closed and we should always make a new post or use the "ask a related question" when starting a new topic.

    The default IDRIVE setting is too high for most FET models, could you please tell me the following:

    What is your required motor phase rise/fall time?

    What model FET are you using?

    How many FETs are used per gate output?

    Any series components in the gate path between the DRV and the FET gate pin?

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 60 points

    What is your required motor phase rise/fall time?

    Reply: PWM rise/fall time is less than 1000ns

    What model FET are you using?

    Reply: Infineon-IPB042N10N3

    How many FETs are used per gate output?

    Reply: One PWM to drive one MOSFET

    Any series components in the gate path between the DRV and the FET gate pin?

    Reply: If no resistor connected between DRV8350 gate driver and MOSFET, it will be damaged 100% and the resistance will drop to < 1M ohm for one of three phase low side pin. So we have to connect a 51 ohm resistor between DRV8350 gate driver and MOSFET. moreover, setting the turn on current to 300mA and turn off current to 600mA. It can load current to 100A, But sometimes, it will protection by VCP under-voltage, the minimum voltage is about 4V.

  • 0 in reply to user3771213
    TI__Guru 65430 points

    Wilson,

    I am calculating the needed IDRIVE strength using this guide: https://e2e.ti.com/support/motor-drivers/f/38/t/796378

    16nC/1000nS = 0.016A or 16mA. This means that 300mA is way too much IDRIVE and it should be set to the lowest setting of 50mA/100mA.

    When the IDRIVE is too high it is possible to damage the device with oscillations/overshoot/undershoot on the gate and switch nodes.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 60 points

    How to config the output voltage and charging time to adjust the drive capability?

    Thanks

  • 0 in reply to user3771213
    TI__Guru 65430 points

    Wilson,

    The voltage cannot be changed, only the current, this current will influence how fast the gate is charged and therefore how fast the output will slew.

    Regards,

    -Adam