MOSFET Discharge damper

100

01:10:34

This uses a Inductor damper to help the MOSFETs capacitance discharge and recharge more stable. If you use the switch, you can see the wave changes from a very erratic ripple, to a smoother discharge and charge. LED can visually represent how it works, and how it is important to high frequency MOSFET Switching.

published 10 years ago

hurz

10 years ago

In principe its a good idea, however you compare different coil values one 3uH which makes ringing and then why not again 3uH which does not show ringing? 47uH is a total different setup. Anyway the ringing is not gone. So dampening is not down to critical point. Default cap of LEDs and mosfets is within EC always 5pF but it seems to be even more even i remove the LEDs which are definitive not helpful for analysis its still ringing and also with lowering the resistor, this is a little phenomen. Any idea?

SigmaEOD

10 years ago

I used the values I did to give a better visual representation of what I was doing,l. The 3uH inductor is the only way I could get the discharge to show. If i wanted to fully eliminate it, depending on what MOSFET, I Would use a 100uH instead of a 47uH

SigmaEOD

10 years ago

In the case of this example, I'm currently working on High frequency Flybacks for an independent study, and I needed a way for the MOSFET to switch Quickly and efficiently

hurz

10 years ago

You try to demonstrate a bad effect, so make both situations equal and show what you do against that bad effect, but don't change the initial conditions! Make a demo both with e.g. 47uH and show up how damping by a resistor does change the ringing. Just my 2 cents.

SigmaEOD

10 years ago

Good Idea, thanks for the feedback

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