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TMS320F280039: Can I change DCDC frequency when DCDC is operating?

sangmo kim
Prodigy 210 points

Part Number: TMS320F280039
Other Parts Discussed in Thread: TIDM-02000, C2000WARE

Tool/software:

Hi,

I am developing PSFB DCDC converter as referance TIDM 02000.

I want to know frequency change method when DCDC is operating.

I herad before, if EPWM set th shadow load mode than DCDC freauency can change when DCDC is operation.

In TIDM 02000 firmware, EPWM is set direct load mode.

 

During DCDC operate, Is there DCDC frequency change method?

Best Regards,

Sangmo KIM.

  • 0
    TI__Expert 4750 points

    Sangmo,

    In TIDM-02000 PSFB DCDC converter reference design, control has been implemented using peak current mode control. In this control, inner current loop is implemented using internal analog comparator subsystem CMPSS. In this method, comparator compares reference ramp with measured current and when measured current is greater than reference, it generates cycle-by-cycle trip which turns off ePWM of lagging leg which is running at 180deg phase shifted than leading leg. Leading leg is operated at fixed frequency. Doing this will control phase shift required to deliver reference current. Considering nature of this control action, it can't be shadow and action has to be immediate. 

    Regarding frequency reduction mode, it is used only for improving converter efficiency at light load.

    Regards,

    Sumit

  • 0 in reply to Sumit Patil1
    Prodigy 210 points

    Hi Sumit.

    Thanks for your reply.

    I understand it well thanks to your explanation.

    Is there Frequency reduction mode? Could you detail explain method? (Please tell me how modify firmware)

    I think if DCDC switching frequency can be reduce, DCDC switching frequency can be increase.

    I am finding method that voltage regulation is good at load dynamic state.

    So I want to change DCDC switching frequency at load dynamic state.

    Best Regards,

    Sangmo Kim.

  • 0 in reply to sangmo kim
    TI__Expert 4750 points

    Hello Sangmo,

    In the DPSDK, if you refer C2000Ware_DigitalPower_SDK_5_02_00_00 or earlier, there is a reference PMP23126 which is based on TIDM 02000 with slightly different synchronous rectification scheme. that explain frequency reduction mode operation implementation and reference code. Please install that version and refer this ccs project and software documentation to understand how it can be implemented. Let me know if you have any questions in that.

    Regards,

    Sumit