HV Flyback capacitor chargers

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[@NNNILabs]

Thank you so much for making this video! I spent four years working with the flyback topology and realized that it's ideal for capacitor charging, the LT3750 totally convinced me about boundary conduction mode (BCM, also called critical conduction mode or CCM)! I ended up making a video about why they are ideal for the job and how to squeeze the most power out of a given set of constraints

[@sambenyaakov]

Great to hear! Please send me the link to the video.

[@TURBOSLAYERPWNZ]

thats exactly why I am into flybacks so much!)

[@sambenyaakov]

😊👍

[@Konecny_M]

It would be interesting to discuss the implications of including a voltage multiplier on the transformer output, as it is no longer purely flyback topology, but rather hybrid with forward converter. The induced current peak superimposed onto the usual constant slope ramp of flyback converter makes current mode control more difficult, especially so in instances where output voltage set point needs to be adjustable. So far my personal experience is that COT voltage mode control is best suited in such cases.

[@sambenyaakov]

Thanks for input

[@Eldon_Dice]

Wow, amazing stuff. I'm currently designing an isolated (1.5kVDC Rated) flyback which will be integrated into a large battery energy storage system. It's also primary control so all your videos have been relevant, thank you! I recommend a topic that is very important - CMTI! What is it? How to measure it? How would a y-cap impact this? How to measure the value across a couple instructors ( flyback transformers)?

[@sambenyaakov]

Thanks for the suggestion. Perhaps.

[@jiefang11]

So good! Thanks again 🎉

[@sambenyaakov]

👍🙏

[@tranxn7971]

Tanks a lot, prof. Very interesting :)

[@tamaseduard5145]

👍🙏❤️

[@sambenyaakov]

👍🙏😊

[@ronaldo0grande]

❤

[@sambenyaakov]

👍🙏

[@sc0or]

That’s the first time I hear BCM. Typically it’s called ZVS, isn’t it?

[@sambenyaakov]

NO. ZVS is an attribute of BCM. ZVS is found in other circuits., e.g. resonant converters.

[@sc0or]

@@sambenyaakov Thank you sir. It would be interesting to hear something about this in your further presentations. Because for me ZVS means a condition when there are no high current and high voltage at the same time. Just like BCM (current ends, and voltage is applied). And I saw many ZVSes related to full/half bridge SMPS as well (like to introduce an additional dead time for one leg to achieve a ZVS)

[@JacquesMartini]

@@sc0or ZVS means Zerro Voltag Switching. This means at the time a semicoductor switch, aka transistor, is switching, the voltage across it is alomost zero. The current can be high during turn off, it is still zero voltage switching. This reduces the switching losses. There is also ZCS, Zero Current Switching. To achive one of the two modes, you need some kind of resonant circuit and the right timing.

[@sc0or]

@@JacquesMartini That's a great explanation sir. Thank you. Now I think BCM relates to an inductor, and ZVS/ZCS relates to a switch. Is that right?

[@sambenyaakov]

@@sc0or BCM has to do with the inductor current, it means that the inductor current drops to zero and increase immediately again.