Continuing education lectures: MOSFET datasheet - Part 2

[@Conservator.]

Dear Professor, I just want to say that I enjoyed the full 41minutes and 4seconds of this video! It’s nice to understand mosfet as switchers and grasp the basic operation of buck converters, SMPSs etc. But it becomes really interesting (as with almost everything) when you dive deeper into the nitty gritty details. I’m far from being able to design (or even parameterize a design) but thanks to your video’s I’ve become aware of the trade offs that have to be made when designing these type of circuits. Thank you!

[@sambenyaakov]

👍😊

[@thanhtuansti]

Hi Sam, Thank you! These two videos are the most practical lessons I have learnt about MOSFET. Best, Tuan

[@sambenyaakov]

Thanks

[@johnaweiss]

17:23 I loved the entire lesson on soft switching embedded inside this lesson on Mosfet datasheets. It could be a video by itself.

[@sambenyaakov]

👍🙏

[@fakduken9775]

Thank you for the lecture.

[@sambenyaakov]

Thanks

[@jamilbabu4637]

Thank you for the video. I need detail explanation of IGBT datasheet video, If available ,please send me the link

[@johnaweiss]

Since a diode with a smaller drop has less reverse recovery, does that mean that reverse recovery is proportional to drop? And therefore, drop has something to do with the amount of charge contained in the diode?

[@sambenyaakov]

The reverse recovery is not related to the voltage drop but to the stored charge. High voltage diodes have a high voltage drop but may be fast

[@johnaweiss]

@@sambenyaakov Is there a diode specification which indicate the magnitude of the stored charge?

[@sambenyaakov]

@@johnaweiss Yes in Datasheet of fast diodes

[@johnaweiss]

@@sambenyaakov Is there a direct relation between diode speed and storage magnitude?

[@sambenyaakov]

@@johnaweiss Yes, for the diode to be fast you need a small stored charge.

[@johnaweiss]

18:43 Will the parallel Schottky remedy work at 100 kHz?

[@sambenyaakov]

Yes

[@sahillabhshetwar2739]

12:13 reverse recovery losses in mosfet

[@sambenyaakov]

?

[@sahillabhshetwar2739]

Comment the time of someone is Looking for just that part. He can directly reach that part of the video , saving him time

[@sambenyaakov]

@@sahillabhshetwar2739 thanks

[@mahanteshteli9300]

Hi Sam , @ 10.04 , you mentioned that when Q2 is OFF then the Inductor current will pass through the body diode of Q2; Does I_L will pass through body diode of Q1 as well to Vin , since both diodes are same direction. plz explain, how it works. ?

[@sambenyaakov]

Depending on the current's direction it may pass through the diode. If the current is lagging, the current will first pass through diode and then via transistor.

[@mahanteshteli9300]

Hi Sam, Thanks for your response. I assume you are referring to Q1 body diode and reverse current flow to Vin when Q1 is off condition. and may i know what condition current will lag. ? could you please make a video of selecting HS and LS MOSFETs for Synchronous DC DC with real time application spec and behavior of MOSFETs during DCM and CCM operation.

[@smartups1]

Sir please make a lecture video on uni-polar and bi-polar sine wave inverter with feed back control .(Detailed)

[@sambenyaakov]

Will try/ Thanks/

[@aliali-ce6zp]

Sir what does the 300us< Pulse 2% < duty cycle relate to ? Is it the quickest way to find the t_on and t_off times for pwm?

[@sambenyaakov]

Please indicate the time of the video frame you are inferring to.

[@khedayache1646]

Dear professor, first thank you so much for this video. I m looking for a mosfet with trigguer intrence. Does that exist?

[@sambenyaakov]

trigguer intrence? please explain

[@khedayache1646]

@@sambenyaakov dear professor, I am trying to use a mosfet as a switch to control something that vary gradualy. I was wondering if I could turn on my mosfet at some level and turn it of on another level during this variation. I m not able to add a smith triguer to the system before the mosfet driver. Thank you in advance

[@snnwstt]

21:32 Why adding the fast diode? Any significative current trying to pass through the intrinsic diode will be "stop" by the external low voltage diode that we have just added, isn't it? Is it that the benefit of possibly turning the MOSFET at 0V is involved behind the reasoning? ( I haven't look at your other two videos, yet, sorry if the answer to this question is there :-) )

[@sambenyaakov]

The reverse current is fed from an inductor. You must provide a path otherwise a voltage will build up and among other things, will blow up the low voltage diode.

[@snnwstt]

Now it is evident! Thanks!

[@shnuk007]

Hi Sam, In the datasheet is written that RGI - Gate Input Resistance is 0.74 Ohm. Should not it be a very high value? In Mosfet transistors there is not current that flows to the gate. (only during switching to charge the capacitor) Could you please clarify this parameter? Thanks

[@sambenyaakov]

This is in series with gate ans isolation (relevant to transient currents) not gate to source.