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DRV8307: I have designed drv8307 motor driver as same as 8307EVM i finding large current drawn from customized board as compared to EVM board

adarsh shetty
Prodigy 105 points
Part Number: DRV8307

Hello

I have designed drv8307 motor driver as same as 8307EVM i finding large current drawn from customized board as compared to EVM board in ln load conditions.

arrangement, Enable- low , Brake - low, DIR - low/ high

given input pwm of 16Khz

in EVM IC555 has pwm of 25Khz

Also some kind of vibrations are found in motor, is this depends on input PWM signal.

Please help me out,

Thanks in advance

Regards,

Adarsh

  • 0
    TI__Expert 4435 points
    Hello Adarsh,

    What large current draw value are you expecting in your new board? what is the current value under the same conditions in the DRV8307EVM?
    Do you have the same layout as the DRV8703EVM on your board? if so, can you set PWM input of your board to match the EVM's, What do you see under that condition? If possible please share your scope findings. Thank you very much.
  • 0
    TI__Guru** 114905 points
    Hi Ardash,

    There are a couple of debugging steps you can try.

    1) Can you connect the PWM input from your board to the EVM. There is a jumper that will allow this. Does the EVM operate properly?

    2) Assuming the EVM still operates properly, please compare all the inputs and outputs of both boards. look for differences and determine what is causing them.
  • 0
    TI__Expert 4650 points
    Hi Adarsh,

    Your input PWM frequency to our device is independent of the output PWM frequency (see section 7.4.1 on page 19 of the DRV8307 datasheet). 16 kHz input frequency should not be an issue.

    Does the motor spin at all in your testing? Have you made sure the hall-sensors are correctly connected to your board? See section 8.1.1 of the DRV8307 datasheet for correct hall sensor configuration.
  • 0 in reply to Luis Riveros
    Prodigy 105 points
    Hi luis,

    thank you for the suggestions.

    the issue has been solved, i had problem in layout tracks .

    thanks & Regards,
    Adarsh
  • 0 in reply to adarsh shetty
    TI__Expert 4435 points
    Hello Adarsh,

    I am glad you resolved your issue. Thank you for the response.
  • 0 in reply to Luis Riveros
    Prodigy 105 points

    hi team,,

    Further to which, i am able to complete my functionality of device and in per-compliance testing stage.  i am facing issue in Radiated emission test getting emission noise from my motor driver section. getting 45dbu/m in the range of 40- 70Mhz range. I suspected my PCB issue.

    i am helpless i tried to understand more better by interfacing with TI8307 EVM board and tested in chamber , emission level is same as previous. i wonder whether its PCB issue or Its general that DRV8307 will emits that mush noise. (load of 1.5A) my doubt is DRV8307 internal clock for gate drives emitting the noise.. please help me out.

    below are the graphs for your reference.

    Range is 30M-1GHz

    Peak on V :

    Peak on H :

    Thank you in advance

    regards,

    Adarsh

  • 0 in reply to adarsh shetty
    TI__Expert 4435 points
    Hello Adarsh,
    Could you please upload the images again.
    It looks like they weren't attached. Thanks
  • 0 in reply to Luis Riveros
    Prodigy 105 points

    below are the graphs for your reference Tested tested with TI DRV8307 EVM board. input PWM is from on-board pwm generator IC555(25kHz frequency). Power supply 24V adapter type SMPS (CE complained)..

    Range is 30M-1GHz

    Peak on V :

    Peak on H :

    Thank you in advance

    regards,

    Adarsh

  • 0 in reply to adarsh shetty
    TI__Expert 4435 points
    Hi Adarsh,
    Is there a specific reason why you are doing 10 meter measurement rather than 3 meter measurement?
    Also, our EVM are for evaluation purpose so exposed headers (which radiate emissions) are intentionally placed for customer evaluation.
    For an actual design is recommended to follow best practices for reducing EMI in a PCB layout. Some common methods are shielding, single point star connections depending of trace type.
    For starters, please try placing a ferrite bead at you supply and some low - ESR decoupling capacitors connected as close as possible to your output FETs and see if there is an improvement. I hope this helps, thank you.