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TIDA-01485: TIDA-01485 start up

Part Number: TIDA-01485
Other Parts Discussed in Thread: DRV8323, TIDA-01516, BOOSTXL-DRV8323RH

Dears,

I am testing TIDA-01485 now. Here is a problem.

In both light load and heavy load mode. Sometimes, could not start up automatically.

Any suggestion for this problem?

  • Hi Zhengqing,

    I have not seen this problem previously. Can you help me to understand the scenario a bit better? Are you using the firmware downloaded from http://www.ti.com/tool/TIDA-01485 or have you developed your own firmware? When the motor is not starting up, please check the gate driver fault indication, which can be observed on the red LED "D2" (which will blink) or monitor the signal at the FAULT pin of gate driver DRV8323? Please check the PWM signal from the MCU and the gate driver output. I would like to understand, whether the problem is from the MCU firmware, or gate driver fault or on the MOSFETs.

    Thanks,

    Manu

  • May I have your Email address?
    I could explain the problem via email.
    Many thanks.
  • Dear Balakrishnan,

    My motor can operate correctly.
    However, sometimes, motor cannot start up unless I push the rotor (no matter which direction.)
    Then, motor can move.
    The design files are all from www.ti.com/.../TIDA-01485
    Any suggestion?
  • Hi Zhengqing Wang,

    My understanding from your response is that you are using the same firmware as given in TIDA-01485 page. If so, please check the below points.

    1. When the motor is not starting whether the gate driver is giving any fault, please look at the nFAULT pin or LED D2.

    2. Whether the motor is taking high current like a blocked rotor condition or only taking low current. THis depends on your POT voltage reference for speed command.

    3. You can also try with increasing the start up duty cycle, which can be changed at the TIMER initialization "Init_TimerD", by changing the initial value of  TD0CCR1 and TD0CCR2.

    4. I also doubt, whether the PORT interrupts are happening properly. Which needs to be verified. A quick check will be, remove the hall state reading and commutation from PORT2 ISR  Vector and place the same in the TIMER D ISR and see whether the problem is solving.

    Thanks,

    Manu

  • Dear Manu,

    Many thanks for your help. I tried all the point you list.

    For 3 and 4,

    I tried these method, but the motor still can not work properly.

    For No.2, when motor stop, the current is around 50mA. for running case, the current is around 250mA.

    For 1.

    I test the waveform from  FAULT showing as follow:

    For motor stop:

    For running mode:

    Here is the problem: no matter motor operate or not, there still has wave in fault pin. That's real strange. 

    Furthermore:

    For the unstartable condition:

    The motor will route a very small angle when power on. When I power off, the motor will turn back to the start position.

    If i push the motor route when powered on, motor will start to turn. Otherwise the hole system will stuck at this condition (small angle when power on, turn back when power off )

    I use the original file from web, any suggestion for this case??

    Manythanks

  • Hi Zhengqing Wang,

    If the Fault pin is going down during the normal operation, that may be due any Fault warning. Please look at the datasheet of DRV8323 and the configuration in TIDA-01485 firmware, to check what is the cause for fault warning. There are some faults which can be configured as warning only.

    Have you tried the steps 3 and 4 in my previous suggestion?

    Thanks,
    Manu
  • Dear Manu,

    You mean the fault port will have kind of PWM wave during normal operation?

    I tried step3 and 4 already, but the problem is still there.

    Many thanks.

  • Hi Zhengqing,

    If everything in the circuit is working properly, the fault output should be maintained high always. Now if the fault output is toggling, that means there is some fault condition existing in the board. Will you be able to try disabling the fault settings in DRV8323 one by one and see which fault is causing the issue?

    My understanding from the above analysis is that, you are getting the fault pin toggling even when the motor runs, which is not expected. Please look at the DRV8323.h and DRV8323.c files in the firmware of TIDA-01485 to change the register settings of DRV8323 for disabling each fault one by one.

    From motor point of view:

    - Please make sure that all the three hall sensors are connected properly and I would recommend you check the hall sensor waveforms coming to the board.

    If one hall sensor is missing, that can cause similar issue where the motor may start some time and will not start at other times. Please check this on priority. Also check the hall matching.

    Thanks,

    Manu

  • Hi Zhengqing,

    I have not heard from you and hope you might have solved the issue. Let me know if there is still some question.

    Thanks,
    Manu
  •  Dear Manu,

    Thanks for your reply, here is the problem. I can run my system with 6x PWM mode. 

    I want to use that in 1xPWM mode. How could it be possible. 

    For three hall sensors, all hall sensors signal are caught.  

    What I use is 8323RH, it doesn't has SPI control port.

    Any suggestion?

  • Hi Zhengqing,

    For 1xPWM mode, please check the datasheet of DRV8323 for the hall signal connections. Please note that the INLC pin of DRV8323 acts as the nBRAKE signal and is to be pulled high for normal operation. Also set the DIR pin accordingly. In the hardware version DRV8323RH, the MODE pin has to be set accordingly to enable 1xPWM operation. Please check the matching of hall signals and motor back EMF.

    The TI design TIDA-01516 (http://www.ti.com/tool/tida-01516shows the 1xPWM mode using SPI version of DRV8323. Also you can look at the EVM "BOOSTXL-DRV8323RH" for the schematic of DRV8323RH based circuit. http://www.ti.com/tool/BOOSTXL-DRV8323RH

    If you are seeing FAULT signal during starting (which may be a cause of start up issue, and we need to find the root cause for the same), I would suggest you to toggle the ENABLE pin of DRV8323, as per the timing specified in the datasheet (An 8 to 40-µs pulse on ENABLE pin can be used to reset fault conditions.)

    Let me know if you have any further question.

    Thanks,

    Manu