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About Digital Power Library and CLA

Barry Mok 1
Intellectual 360 points
Other Parts Discussed in Thread: CONTROLSUITE

Hi all,

We are now designing a control system for a power supply application.

 

I found that in the new version (v3.4) of the digital power library, a DPLib CLA C is added where the CLA implementation can be done in C programming instead of assembly code.

 

BTW, I am now considering to use F28335 for my application and finding that F28335 seems not support for the CLA application.

 

It seems that ControlSUITE finds more software support for F2803x on digital power control application. Also, I found in the template project folder (C:\ti\controlSUITE\development_kits\TemplateProjects) that there is no DPLib template for the F2833x CPU but there is a simple F2833x template for LED flashing.

 

So, may I ask the following questions?

 

  1. Any DPLib template for F2833x will be published by TI and what is the schedule?
  2. Any DPLib C code implementation will be published similar to DPLib CLA C?
  3. Can F2833x support CLA?
  4. I found F2803x don’t have FPU while F2833x have. However, F2833x don’t have CLA. So, which of the following configurations get a better performance?

A: F2833x with DPLib

B: F2803x with DPLib CLA

 

BR,

Barry

  • 0
    TI__Guru 57255 points

    Barry,

    I will attempt to answer your questions:
    1) Any DPLib template for F2833x will be published by TI and what is the schedule?

    [BL] Most of our customer base in the digital power is concentrated in the lower-cost Piccolo family (F2802x, F2803x, and occasionally the F2806x families).  As a result we haven't concentrated as hard on making a DPLib available for the Delfino F2833x family.  Finally, I am not aware of a program to make a special DPLib for the F2833x. 

    That being said, we do have a predecessor library to the DPLib that is available within the pre-controlSUITE "Baseline software" package.  It and the TMDSDCDC2KIT application software could be used as a good reference.  Note that we are not updating this software any more and are no longer supporting it as thoroughly.  Both packages are available at the link below:
    http://www.ti.com/tool/tmdsdcdc2kit#software


    2) Any DPLib C code implementation will be published similar to DPLib CLA C
    [BL] We have considered doing something like this, but haven't decided to do it yet.  Typically, digital power control loops are demanding for the processor and so an assembly-macro based approach was our first option when making a library.


    3) Can F2833x support CLA?
    [BL] The CLA is like a hardware co-processor specifically designed to make tight control loops possible.  The F28335 does not have the CLA peripheral.


    4) I found F2803x don't have FPU while F2833x have.  However, F2833x don't have CLA.  So, which of the following configurations get a better performance?
    A: F2833x with DPLib
    B: F2803x with DPLib CLA

    [BL]  This is a difficult question and one that depends on your applications usage of the resources available in both chips.  This is because you have a 150MHz floating-point CPU vs a 60MHz CPU + 60MHz floating-point CLA.  Depending on your application you may be able to run the control loop fully on the CLA and leave the CPU open to do communication, background tasks, etc.  What power topology at what switching frequency are you considering? 

    Note that the F2806x family may also be interesting to you since it is between these two processors in its chip specifications.


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Intellectual 360 points

    Dear Brett,

    Thanks a lot for your very detailed reply. We would like to design an half or full bridge inverter with frequency 20 to 30kHz with SPWM control. The system is required to:

    1. Sense DC link voltage and current, AC voltage and current.
    2. Check the phase different between the AC voltage and current and adjust an appropriate power angle with a control loop, may consider implementing with CLA.
    3. Adjust an appropriate AC voltage with a control loop, mayl consider implementing with CLA.
    4. Calculate the complex AC power by using either C28x Fixed Point DSP Library (in case of F2803x) or C28x Floating Point Unit DSP Library (in case of F2833x).

    Three approaches are now considering:
    Plan A: F2803x, DPLib, Fix DSP Lib (can use TMDSHV1PHINVKIT as reference)
    Plan B: F2803x, DPLib CLA C, Fix DSP Lib
    Plan C: F2833x, DPLib, FPU DSP Lib.

    Thanks and regards,
    Barry

  • 0 in reply to Barry Mok 1
    TI__Guru 57255 points

    Barry,

    It seems like you are on the right track.  I would also recommend referring to the TMDSHV1PHINVKIT as a reference so that you can leverage the work that we've already done (at least to some extent).

    Note that the TMDSILPFCKIT has some software for power measurement inside it's project.  It's also for the F2803x.

    I think your issue will be trying to do all these things simultaneously although it's not impossible.  That being said offloading some work to the CLA, whether that be the power measurement calculations or the control of your inverter's voltage/phase, may be beneficial.

    I think I'd choose to start with the F2803x family (60MHz fixed-point CPU w/ CLA) or the F2806x family (90MHz floating-point CPU w/ CLA and more memory) depending on how much else is going on. 
    (the F2803x code should migrate to the F2806x device almost seamlessly because all peripherals on the F2803x exist on the F2806x.  You'd just need to change the linker command file and the header files)


    Thank you,
    Brett