Forward converter lossless snubber

[kekon]

I'd like to use lossless snubber in some of my designs but there is one thing that is unclear to me. I've the following snubber in one of the Meanwell power supplies:

https://electronics.stackexchange.c...rward-converter-how-to-dissipate-leakage-indu

If i get this right when the transistor is turned on, the C1 capacitor is charged to -Vin by the reset winding. When the transistor is turned off the magnetizing inductance is discharged by reset winding to Vin. The energy stored in leakage inductance is pushed into C1. As a consequence its voltage will rise. But how on earth the capacitor is discharged back to -Vin ? I just can't see any path in this cirucit that could discharge the capacitor to Vin power source. During the "off" period, the voltage at the D1 anode is negative therefore it does not conduct. It seems that when the transistor is off the C1 capacitor and the reset winding form two voltage sources connected in series with their negative terminals shorted. I just can't understand how this can work, or maybe i'm wrong somewhere ?

 

[treez]

Hello,
Well here is an ltspice sim of your one TF converter with the snubber capacitor...so you can fully investigate…but still, for offline use, the 1TF is pretty poor because the drain voltage goes up to 800v approx. at turn off….so that’s some decent size switching losses.
LTspice is a free download.