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TMS320F28377D: Single Core or Dual Core

David C
Expert 3350 points
Part Number: TMS320F28377D
Other Parts Discussed in Thread: DESIGNDRIVE

Hello,

We have been using TI F2812 or TI F28335 in all our motor drive designs. Now the SiC power switch is the trend in the motor drive industry.  SiC allows us to switch at  much higher frequency (at least two times) . But this imposes more stringent requirement on the horse power (speed) of the micro-controller.

We would like to know what more powerful processors TI offers with -55 to 125C temperature rating. Otherwise we will be forced to switch to ARM or FPGA solutions.

I've looked at the TMS320F28377D-EP released. It is dual core 200Mhz but we haven't worked much with dual cores almost all of our projects  are currently running on a single core DSP. 

The 200Mhz will improve over our current  the 150Mhz processor. The ideal candidate would be > 200 Hz single core and backward compatible with 28335 or 2812.

Are the software written for 28335 compatible with the 28377? Do we need to re-write the software to take advantage of dual processor?

What is the purpose of dual processor? To control two motors? The question is how we benefit from dual core when we just need to control one motor?

Aside from that, I noticed that the 176 pin 28377 is not compatible to 176 pin 28355.

Regards,

David

  • 0
    TI__Expert 7650 points

    Hi David,

    You have many C2000 options for improving your control of higher switching speed inverters.  One thing that I will point out is that the current loop control bandwidth can improve without increasing the switching speeds depending upon your approach to the current loop.  For example, if you aren't double sampling today (sample period of 1/2 the PWM carrier period) you may want to consider that.  Also, you may want to investigate the C2000 DesignDRIVE Fast Current Loop (FCL).  Using a single C28x and CLA pair (of the '37xS family, the 37xD is not required) a 910 ns current loop is possible with the Fast Current Loop project.  That means that, leveraging our immediate PWM update mode, the total time from sample to PWM update is only 910 ns.  Please see the fast current loop blog as an entry point to learn more about how FCL can deliver 5kHz of current loop bandwidth using only a 10kHz carrier.  Of course, FCL is also beneficial if the PWM switching frequency is increased, too.

    The F2837xS family is software compatible with the CPU in the F28335.  However, it is a few of the new features, like the Trigonometric Math Unit, that help make the '37x so much better at FOC vs. the '335. 

    The dual core architecture can be applied in many different ways because of how resources are shared on-chip.  It is up the you, the designer, as to how the computation is partitioned, but yes they could operate sequentially or in parallel to each other or possibly one as a 'checker' to the other.  

    With the '37x family you also have access to the Code Law Accelerator, or CLA, that is a second, 200 MHz 32-bit floating point core that can be used to offload some critical control functions from the C28x. Again, the functional partitioning is up to you for what is suited best for your system.

    For -55C operation, you will have to work with the -EP versions of C2000 products, since our standard devices are tested for -40C junction temp.