I have been for the past 3 months trying to design and experiment with topologies to charge a high voltage capacitor up to 1 kV. I have settled on a classic flyback topology:
I have tried several transformers and understand how important elements such as the turn ratio, switching frequency, core type and leakage inductance impact my application. I struggle however to understand the following formula: Vo = N . Vi . D / (1-D), where D is the duty-cycle (D = ton. fSW). This would imply that to get my high voltage capacitor up to 1 kV from a 12V source I would need an 83 turn ratio. However, I have seen multiple designs where a low turn ratio transformer is used to generate high voltage such as the following:
I found contradicting information left and right on the forum about a high turn ratio. I have read explanation to view the flyback topology from the perspective of energy transfer and that what I am looking at is delivering pulses of current on my secondary to gradually charge my capacitor to the desired voltage. Is there an assumption on the formula that I am missing? How is it possible that we can observe a high voltage on the output with low turn ratios?