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TMS320F28376S: about the ANC system design

Kai Lai
Expert 6336 points
Part Number: TMS320F28376S
Other Parts Discussed in Thread: DAC70501

Hi Expert, 

My customer now is target to design a ANC (Active Noise Cancellation) system, and they are searching our ADC / DAC or MSU based total solution, need expert to provide the recommendation and technical topic reply here. Thanks for your support in advance!

Can you help to check  does our TMS320F28376S can as a total solution and fulfill below requirement ? Does we have any experience before to check the latency estimate?

-------   Requirement spec   ---------------------

  1. Group delay: <120us @48Khz sampling rate (ADC+DAC only, SAR ADC is recommended)
  2. ADC/DAC bit resolution: >= 14bit(applying audio scope)
  3. Port #:  ADC: 4 input (support dual channel sampling simutaneously, at least)
  4. Port #:  DAC: 2 output

<audio path> as below

BR,

Kai

  • 0
    TI__Mastermind 30180 points

    Hello Kai,

    The information below is available in the datasheet (see section 7.10.1 on the ADC specification):

    1. The F2837xS lists the 16-bit differential ADC as having a sampling rate of 1.1 MSPS (table 5-1 Device Comparison); given the control loop of the customer is not too long a sampling rate of 48 kHz should be achievable; this device does use a SAR ADC
    2. The 16-bit differential ADC's Effective Number of Bits (ENOB) is measured at about 14 bits; the DAC has a resolution of 12-bits, I do not believe there is any way to alter this
    3. I'm not completely certain about what this point is asking; simultaneous sampling is achievable since there are multiple ADC modules on a single device (depending on the package used, there can be 2-4 ADCs available). Is the customer looking to do simultaneous sampling for 4 different inputs, or are they sampling 4 inputs and they want 1 instance of simultaneous sampling (i.e. using 2 ADCs, 4 inputs each)?
    4. There are 3 DAC modules on this device, so 2 outputs is achievable.

    Let me know if there are further questions.

    Best regards,

    Omer Amir

  • 0 in reply to Omer Amir
    Prodigy 50 points

    Hi Expert:
    Our application is in motor noise cancellation only.  If DAC resolution apply in 12 bits replace of 14 bits. Is it key factor for ANC performance impact? 

    Thank you in advance!

    BR/Elvin

  • 0 in reply to Elvin Shih
    TI__Mastermind 30180 points

    Hello Elvin,

    I will try to get in touch with an expert who knows ANC, I will get back to you once I have an answer.

    Best regards

  • 0 in reply to Omer Amir
    Prodigy 50 points

    Hi Expert:
    In our application also need to have a 28V BLDC motor control.  If we use TMS320F28376x for both motor control and ANC total solution. Does it be recommended solution.  Is there any technical concern to pay attention if yes.

    Thank you!
    BR/Elvin

  • +1 in reply to Elvin Shih
    TI__Expert 3390 points

    Hello Elvin,

    unfortunately we cannot tell you if a 12-bit or 14-bit DAC for noise cancellation will be required for your specific application. When you are in doubt that a 12-bit DAC is sufficient, you may use an external 14-bit DAC DAC70501 (16-bit, 14-bit and 12-bit variants available) with SPI interface and scale down or even up depending on your system testing. 

    With respect to running two real-time control algorithms in parallel. It depends on the PWM control loop update rate. For example we often see 16kHz PWM for the BLDC motor control. For ANC you mention  a group delay of <120us. If you run the ANC algorithm at 16 kHz to, the delay through the control loop is 62.5us. 

    In that case you may process both your motor control (can be trapezoidal or FOC, sensored or sensor-less depending on your system requirements) and your ANC algorithms within 62.5us. For initial benchmarking you may refer to the application note Real-time Benchmarks Showcasing C2000 Control MCU's Optimized Signal Chain: https://www.ti.com/lit/an/spracw5a/spracw5a.pdf for algorithms like Clarke/Park (used in FOC) or PID Controller, or refer to the C2000 E2E forum.

    Regards,
    Martin Staebler

  • 0 in reply to Martin Staebler
    Prodigy 50 points

    Dear Expert:

      Very thanks your help!!

    BR/Elvin