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TMS320F280049: Real-World Applications of the PWM Chopper Block in C2000 ePWM Module

Part Number: TMS320F280049


Tool/software:

Hello TI Experts,

I’m exploring the PWM Chopper Submodule in the C2000 ePWM module and want to understand its real-world applications beyond theoretical use.

1. Where is this feature actively used?

  • Is it primarily designed for pulse transformer-based gate drives?
  • Are there any practical applications in motor control (BLDC, PMSM), resonant converters, or other power electronics systems?

2. Frequency Considerations

  • Why is the chopper frequency typically in the MHz range, even though the PWM output itself can reach up to 50 MHz?

3. Chopper Pulse Behavior

  • What is the purpose of allowing a different width for the first pulse, while keeping subsequent pulses different?
  • Does this "first pulse setting" apply to:
    1. The very first pulse of the entire PWM signal (PWMxA  & PWMxB both fixed), or
    2. The first pulse of PWMxA and the first pulse of PWMxB separately?

4. How Does This Work with a Pulse Transformer?

  • Normally, pulse transformers require alternating HS and LS switching to avoid core saturation.
  • However, in this case, only the HS is switched with high-frequency chopping before LS takes over.
  • How does the transformer core reset properly in this situation?
  • Wouldn’t the core still saturate if the chopper frequency isn’t high enough?
  • Are there any specific design guidelines or calculations TI recommends to ensure proper operation?

5. Reference Designs & Practical Use

  • Are there any TI reference designs, application notes, or waveform examples that show real-world implementations of this feature?

I’d appreciate any insights or links to relevant resources.

Thanks in advance!

Best Regards,
Abhiraj

  • Hi Abhiraj,

    I am looking into the resources we have that can help answer your questions. 

    Best,

    Ryan Ma

    • Is it primarily designed for pulse transformer-based gate drives?
    • Are there any practical applications in motor control (BLDC, PMSM), resonant converters, or other power electronics systems?

    That is correct, primarily used in pulse transformer applications, mainly to provide isolation from power stage. 

    • Why is the chopper frequency typically in the MHz range, even though the PWM output itself can reach up to 50 MHz?

    Even though the PWM output itself can reach up to 50Mhz, having the chopper to chop up the signals within a PWM period is going to allow you to keep your current resolution while still offering more edges within the period.

    • What is the purpose of allowing a different width for the first pulse, while keeping subsequent pulses different?
    • Does this "first pulse setting" apply to:
      1. The very first pulse of the entire PWM signal (PWMxA  & PWMxB both fixed), or
      2. The first pulse of PWMxA and the first pulse of PWMxB separately?

    The purpose of allowing different widths for the first pulse in the ePWM chopper submodule is to provide flexibility in controlling the initial pulse width. The first pulse setting will be applied to the first pulse of PWMxA and first pulse of PWMxB seperately.

    • Normally, pulse transformers require alternating HS and LS switching to avoid core saturation.
    • However, in this case, only the HS is switched with high-frequency chopping before LS takes over.
    • How does the transformer core reset properly in this situation?
    • Wouldn’t the core still saturate if the chopper frequency isn’t high enough?
    • Are there any specific design guidelines or calculations TI recommends to ensure proper operation?

    Need to gather more info on this.

    • Are there any TI reference designs, application notes, or waveform examples that show real-world implementations of this feature?

    Currently we do not have any TI reference designs that implement this feature.

    https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1396117/tms320f28379d-epwm-chopper-applications

    Best,

    Ryan Ma