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DRV8839: Motor working issue at high speed

Denish Limbachiya
Intellectual 530 points

Part Number: DRV8839
Other Parts Discussed in Thread: BQ24095,

Hello Sir,

Nice to E-Meet with you.

First kindly find attached schematic for motor driver and power supply scheme in which we us TI charging IC BQ24095 and motor driver IC DRV8839DSSR .

Battery Charging Section:

Motor Driving Section:


 

Issue 1: During higher speed LCD back light flickering Issue arrive.

Issue 2: In our device motor can work without battery  by using charger 5V power source. For the reverse protection when i added schottky diode which have 0.3V drop with low Rds then my motor can't work.

 

So my dought on it's that possible driver ic can't give enough current to motor or Charging IC can't give enough current to motor?

 

So kindly suggest us right way i want to understand all scenario what happen kindly suggest us right way for over come from this issue.

My battery is 3.7V 1400mAH, Charger is 5V 1A output, And motor current is approx 250mA and i see the peak current approx 350mA additionally and i use 3.3V 600mA output current LDO for motor supply.

So kindly provide us solution for it in which section need to modify.

Thanks,

Denish.

  • 0
    TI__Guru** 114905 points
    Hi Dinesh,

    Issue 1: During higher speed LCD back light flickering Issue arrive.

    Can you provide more details?
    What is higher speed?
    What is the VM voltage?
    What is the duty cycle?
    Can you provide scope captures of VM, the inputs, and outputs?

    Issue 2: In our device motor can work without battery by using charger 5V power source. For the reverse protection when i added schottky diode which have 0.3V drop with low Rds then my motor can't work.

    Could this be a problem with one of the circuits providing VM to the DRV8839?
    What is the IN voltage at the battery charger?
    What is the OUT voltage of the battery charger?
    What is the voltage of VCC_3V3?
  • 0 in reply to Rick Duncan
    Intellectual 530 points
    Dear Rick,

    Thanks for the response

    Issue 1: VM voltage is 3.3V . Because my motor work on 3.3V so.

    Issue 2: Charger in voltage is 5V
    Charger out voltage is 4.2V which goes in LDO(AP7215-33YG-13) and LDO give 3.3V 600mA output to motor.
    VCC_3V3 means 3.3V DC for motor.

    Thanks,
    Denish
  • 0 in reply to Denish Limbachiya
    Intellectual 530 points

    Dear Rick,

    Sorry, I forgot duty cycle we use 24MHz clock 100% duty cycle at maximum speed

    Thanks,

    Denish

  • 0 in reply to Denish Limbachiya
    TI__Expert 8985 points

    Hi Denish,

    I will be supporting you in this endeavor.

    Now, my coworker Rick had a few more questions for you to answer. Can you provide answers? Thank you.

    Issue 1: During higher speed LCD back light flickering Issue arrive.


    What is higher speed?

               


    What is the VM voltage?

                VM voltage is 3.3V . Because my motor work on 3.3V


    What is the duty cycle?

               24MHz clock 100% duty cycle at maximum speed


    Can you provide scope captures of VM, the inputs, and outputs?



    Issue 2: In our device motor can work without battery by using charger 5V power source. For the reverse protection when i added schottky diode which have 0.3V drop with low Rds then my motor can't work.

    Could this be a problem with one of the circuits providing VM to the DRV8839?


    What is the IN voltage at the battery charger?

               Charger in voltage is 5V.


    What is the OUT voltage of the battery charger?

               Charger out voltage is 4.2V which goes in LDO(AP7215-33YG-13)


    What is the voltage of VCC_3V3?

               LDO give 3.3V 600mA output to motor.

  • 0 in reply to Hector Hernandez Luque
    TI__Expert 8985 points
    Hi Denish,

    Any updates here from your end on these questions? Thank you.

    What is higher speed?


    Can you provide scope captures of VM, the inputs, and outputs?
  • 0 in reply to Hector Hernandez Luque
    TI__Expert 8985 points
    Hi Denish,

    I see no update for the past week. I will close this thread. Please, open a new thread for any further inquiry. Thank you.