Kapanadze Cousin - DALLY FREE ENERGY

[itsu]

Not the same, the drain's rising voltage waveform does not appear rounded at 20μs/div anymore.

Sorry, i meant with "same situation" the mentioned conditions, like pin 3 still floating etc.

It indeed cleaned up the shutdown waveform of the MOSFET, so much for using RC snubbers......

Could this also have caused the gate inactivity when the coils are attached?

Itsu 

[verpies]

Any floating pin including trim pot can easily pick up noise from external.

That's very true even if this pin is internally pulled up with a 100k resistor.

Can you try force enable mosfet driver with a ~1k resistor rather than leaving it floating.

That might be dangerous if he connects this resistor directly to 12V because AFAIR the UCC37322 inputs can take only 6V max.

[verpies]

Pin 3 (enable) of the UCC37322 drivers connected via a 1K resistor to its Vdd (12V).

Can this input take 12V ?

Anyway,  no difference noticed from above screenshots.

Without inductive spikes to interfere with it, there will be no difference.

Regarding the energy of these spikes:
Could you short the secondary winding and measure the inductance of one primary half ?  ...while you have the transformer disconnected.

Also, could you do the same with the other half of the primary shorted?

[itsu]

Can this input take 12V ?
Without inductive spikes to interfere with it, there will be no difference.

Regarding the energy of these spikes:
Could you short the secondary winding and measure the inductance of one primary half ?  ...while you have the transformer disconnected.

Also, could you do the same with the other half of the primary shorted?

Enable at 12V should be fine, see specs.


Shorting both secondaries and measuring one primary gives 5.7uH
Shorting the other primary too then gives 4.5uH

Itsu

[Hoppy]

Thanks Hoppy,    so something like 60V should do.


OK,  RC snubbers removed, for the rest same situation as above.

Yes Magpwr, thats my scope,  now set to averaging 4x


Itsu

Itsu,

It should be OK but I would go higher. The TVS is there only to protect the mosfet, so if your mosfets are rated at say 200V, then I would go for around 70V or 80V. I have used 2 x 47V series connected diodes in the past.