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UCD3138: Configuration of DPWM module for totem pole PFC

Part Number: UCD3138

Hello guys,

currently I have a more complex problem and hope to be able to describe the task understandable.

For a totem pole PFC with UCD3138 I'm looking for a solution to configure the DPWM module properly.
- FET S1 is driven on DPWM1B
- FET S2 is driven on DPWM1A

Positive Half Wave:
In the positive half-wave, the FET S1 operates as the switching element to charge the coil with energy (green path). The FET S2 should operate as ideal diode to deliver the charged energy to the capacitor (red path).

Problem:
Here I would think the DPWM normal mode is suitable. The filters duty acts on the DPWM Output A. However, DPWM Output B would have to be switched off prematurely during the zero-current detection and not only at Event 4. How do I realize that?

Negative Half Wave:
In the negative half-wave, the FETs replaces their functions: FET S2 operates as the switching element to charge the coil with energy (green path). The FET S1 should operate as ideal diode to deliver the charged energy to the capacitor (red path).

Problem:
In my opinion, the DPWM Leading Edge Mode would be suitable. However, the filter duty would have to act on the DPWM output B, but still has an effect on the DPWM output A. In addition, the DPWM output A would have to be switched off prematurely in the case of the zero-current detection and not only at event 1. 

Is there a way to set the DPWM1 module so that the above process can be realized? How can I do that?

Thanks for your assistance!!!

Best regard,

Andreas

  • You've almost got it.  The secret is the Intra Mux bits in DPWMCTRL0.  Put a 3 in both of the INTRA_MUX bitfields, and it will switch DPWM B with DPWM A for the other direction.  Obviously do it at zero crossing, and put the DPWMs in GPIO mode with a low state coming out while you do it. 

    Happy Debugging,

    Ian Bower

  • In reply to Ian Bower:

    Hello Ian,

    thanks for your quick reply and your help. Unfortunately I can not work on my project at the moment, because I have vacation (what a luxury problem!). After that I have to switch to another project. But I will test these settings as soon as possible.

    Best regards,
    Andreas