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CCS/TMS320F2811: IS THE HEAT PROBLEM?

user1020420
Prodigy 40 points

Part Number: TMS320F2811

Tool/software: Code Composer Studio

I am using tms320f2811. Two bldc motors are controlled. 
It has been more than three years since we built our products. 
The heat problem has become a problem in recent years. 
The temperature of mcu is close to 60(c)degrees. 
I wonder if the 2811 itself has a heat-related problem.
  • 0
    TI__Guru* 84230 points

    Thanks for reaching out to the E2E Support Forum. 

    Please give some more detail on the issue you are seeing with the F281x device.  What are the behaivors do you see from your BLDC system that you believe are caused by the MCU? 

    The 281x device is rated for operation to 85C with the "A" variant or 125C with the "S" or "Q" variant, both of which are above the 60C you mention, so this should not cause the issue on its own.  

    Best,

    Matthew

  • 0 in reply to MatthewPate
    Prodigy 40 points

    hi.


    In 2811, the encoder is used for position control

    and adc is used for current control.

    There is no abnormality in motor drive.

    It is the equipment that administers the Ringer's solution to the human body.

    As the temperature of the whole product rises, the temperature of the Ringer's solution, which is made of protein, increases.

  • 0 in reply to user1020420
    TI__Mastermind 26710 points

    Hello,

    Thank you for providing an insight into your system. Is there anything else you can link the problem to other than the temperature? As Matt mentioned, the F281x device should be operable at 60C.

    Have you tried to isolate different parts of your system to narrow down what may be getting affected by temperature?

    Best Regards,

    Marlyn

  • 0 in reply to Marlyn Rosales Castaneda20
    TI__Guru* 84230 points

    To restate the issue you are having, the motors controlled by the F281x MCU is behaving normally, but the heat generated by the control system is causing issues to the other components of your equipment, as you said heating the Ringer's soln which is undesirable.

    While there will be a certain amount of energy transferred to heat by our device, I'm not sure the MCU is the cause of the issue.  Have you been able to take a thermal camera to examine the hot spots?  I would think it is more likely from some IO activity or FET drivers that would dominate any heat profile of a control system.

    In that regard you can try and bring down the active current as much as possible, I would also look to make sure there is not contention of two pins driving against one another as that will cause alot of heat to be generated.

    I'm not very experienced in system thermal management, all of us in this forum are on the C2000 MCU team explicitly, we can look to push this to one of our system's forums or motor driver (like DRV series) forum to see if they have more exposure to these issues.

    Best,
    Matthew

  • 0 in reply to MatthewPate
    TI__Guru* 84230 points

    Wanted to share this app note on power management as it pertains to the system effect.

    http://www.ti.com/lit/slva462 

    Best,

    Matthew

  • 0 in reply to MatthewPate
    Prodigy 40 points

    Hi.

    This is the thermal image.


    It is said that the temperature of the dsp itself is quite high even with the products of other companies I know of using the 2811.

  • 0 in reply to user1020420
    TI__Guru* 84230 points

    This could also be a function of your ground plane design on the PCB.  The heat generated by the power consumption has to escape the device, in this case its either going to be from the package top(as you are seeing), the package bottom or the pins through the VSS pins.  Is there a dedicated ground plane or just trace grounds?

    Have you tried to turn off different functions on the MCU to see if there is a contribution that is much greater than the others?  While it may not be possible to turn this off in your system during run time, it could give us some clue on what is causing this on the device and perhaps how to mitigate it.

    Best,

    Matthew