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UCC29910A: Using with DC Input

Part Number: UCC29910A

What happens when this is run on DC input? Does it operate like a regular buck converter? I'm trying to capture waveforms, but it's very difficult since everything is within the AC envelope (not sure if that's the right term). I can capture a wave using AC Line on the trigger and then zoom in on waveforms, but I lose resolution quickly. I've been experimenting with 170Vdc and it appears to work similar to a buck, but how does it differ from AC input and DC input? There are no pulse width changes because the input isn't changing at all. My goal is to increase efficiency while maintaining a decent PF.

I've also noticed that in the inductor calculation formula, the peak input current is in the denominator, indicating that the higher the current, the lower the inductance, which seems odd to me. I'm not too familiar with how exactly PFC works, so maybe that's part of it. I would think that the more current you have, the more inductance you would need.

  • Hi, Nick

    UCC29910A is designed for Buck PFC with AC input, since PFC is not needed for DC input. But UCC29910A can support DC input, it works link normal Buck. The pulse width is defined by input voltage and CS signal, since input voltage is not changing for DC input, so it is normal there is no pulse width change.

    if you need more power, it need higher peak current of inductance, then it need smaller inductance. since V=Ldi/dt.

    Yunsheng