All 18 minutes pass by like it was 5 minute talk presentation . Thank you Sam .

one of the most under rated channels. I'm writing this comment in the hope to make your channel reach more people, cause youtube only suggests clown channels. I'm really grateful for all the information you are providing us with.

one of the best channels of explanation, complete, precise and extremely detailed.

One of the best technical series on power electronics available. Dr Ben Yaakov is just exellent!!

Thanks for explaining! It is really precious

Thank you! You've answered a question that I won't even figure out to ask. Very interesting material :)

Thank you very much Prof. for this video, without this I never could know about this hurdle hidden under an apparently simple looking riddle.

At 70 I still learn much from your presentations Professor!

Professor Sam. Thanks for another fine video.

yay ... perfect timing for what I am doing today :) thankyou

Thanks professor. Now I understand that you did not intend to get as far here, as the class lecture. Only to discuss the reverse current in itself. Definitely a good lesson in humility for me 🙂. Thanks for the detailed explanation.

Thank you Prof. Watching your explanations makes me wish to physically attend your class. I hope I will get the opportunity someday.

Thank you very much Professor, sharing absolute clear knowledge and teaching, i learned a lot from your videos.

Sam, thank you so much ! This was brilliant ! I am working on a prototype power converter with a 400 V high rail, using a bootstrap circuit for the upper transistor. For the past two days I've been trying to figure out why there is a large spike (only 20 nsec long) during on-switching of the upper transistor, which even affected my 15 V driver supply (which got a little jolt). I've been thinking about the reverse-recovery for the diode (I used an old 1N4007 that I had laying around), but did not think that made sense since the diode should not be conducting at that time... Now I know my problem, and your explanation was (as always) impeccable. Thank you very much !

We are humbled by your wisdom professor.

As usual, very informative and well explained !

Thank you for the video! I recently found that LTspice had always possibility to simulate reverse recovery using parameter vp. But documentation and reference about it appeared only in version Ltspice17 and not in Ltspice4.

a great video thanks Prof

Good explanation.

Very good 👍

Thank you professor. I understand that this is true provided that the dead time period is short enough to prevent the bootstrap capacitor from being totally charged. Right?

Very nice professor 🙏, I believe for GaN Fets the effect of extra charging in the dead time period would be much worse as the reverse voltage drop could be in the range of (Vth+Vgs_off)>Vd_MOSFET... (For the case of outgoing load current)

Outstanding Job x 2.

Perfect presentation (as always). Could you confirm that with LLC or CLLC, as the current is reversed before closing high side, reverse diode recovery is not involved? In other words, no need to have a fast bootstrap diode with resonnant converters.

Thank you very much! My question is: does schottky have better performance than fast diodes?

A Schottky diode does not have any minority carrier charge storage, it is a majority carrier device. The TT term in the PDS5100 model makes no physical sense.

This makes me wonder about the tradeoffs of Schottky vs fast PN diodes in this application. Schottky should have higher leakage but I don't think this would be a significant disadvantage?

Hi Prof.... Its a great video... I have a practical issue in my project.... I'm using bootstarp gate driver for pmsm motor inverter. Issue is as and when I turn ON inverter voltage (270vdc) my low side gate signals are distorting. Could you please share possible reason

👍💖🙏

Sir, what should be the voltage rating required for this diode? Do we have to consider the drain voltage?

Iam afraid I have to disagree. 1.) The startup problem exist only in theory and simulations, since in a real circuit, the driver voltage is applied a LOT of time BEFORE the circuit starts switching. When the low side driver is ON, the bootstrap capacitor has all the time in the world to charge. If both drivers are in tristate and so both MOSFETs are off, the problem will be there. But this is a rather questionable design. 2.) The polarity of the load current or type of load (resistive or inductive) does NOT matter! So does the voltage of MID. When the low side is ON, the voltage of MID will be somewhere around 1-2V plus (negative output current) or 1-2V minus (positive output current, diode conducting for IGBT, maybe reverse mode of MOSFET) . But this does NOT directly define, whether reverse recovery in the bootstrap diode occurs or not. It only amplifies the effect in some cases. 3.) You own measurement shows the real cause of reverse recovers. A very short time between the LOW side going off and the high side going on, in your screenshot ~400ns. When the carging process is not finished before the high side goes on, reverse recovery will occur in the bootstrap diode. This translates to very high duty cycles close to 100% at very high PWM frequencies. 4.) What puzzles me is, that in your measurement the charging process of the bootstrap capacitor starts when the LOW side goes off. This is odd. Usually, this process starts as soon as the low side goes on, since it needs the low side mosfet conducting or at least the MID voltage driven low, which can also happen through an inductive load. I guess your setup uses MOSFETs, and when the low side goes off, the MOSFETs leaves reverse conduction mode (low R_DS_ON) and the body diode has to carray all the inductive output current, which cases the MID voltage to incease with negative polarity! This will start an additional charging process for the bootstrap capacitor.

I have one request, please also upload the simulation file l

Hi master many persons that have excercise in electronics activate in youtube.must her edourment no any result.please as a sample rather than theory go to action an define good base driver