Does FET driver need protection diodes at output (to rail and GND)

[Flyback]

Hi,
We will use TC4428 to drive pulse trxformer as in attached.
Does it need protection diodes at output (to rail and GND)?...to supplement the output FETs' internal diodes, which mightnt be very good?

After all the pulse transformer leakage inductance may well otherwise blow up the IC?

TC4428

https://ww1.microchip.com/downloads/en/DeviceDoc/20001422G.pdf

 

[kubeek]

how would the leakage inductance kill the IC? If the fets are fast and diodes are slow, then I guess there would appear a peak voltage on that output which exceeds the rating of the output fets. If only there was a way to measure that voltage...

Looking at it from the other side, do you think the internal mosfets will turn so abruptly that the body diode will not be able to follow that? (or protection diodes that likely are there without being mentioned)

 

[ronsimpson]

Old data sheets show diodes on the output of the gate driver because of the kick back of the transformer. I have not seen recent data on this. Most people do not use transformers now and IC gate drivers have advanced.

I would layout the PCB with BAT54 dual diodes and then later see if they are needed.

 

[shortbus=]

Most people do not use transformers now and IC gate drivers have advanced.

Just my opinion, but I think the people he works for pay him by the number of components he uses in a design. and his new claim of "just a hobbyist" is another joke.

 

[kubeek]

I would call the diagnosis "overthinking without actually thinking". Too many hypothetical scenarios and searching for hidden what-if flaws, instead of making decisions about the actual design.
Flyback, if you are not sure about something for the design you have two choices: either you go overkill and make sure that your concern wil not ruin your thing even if it is there (especially since you are now a hobbyist), or you take some time to prepare a test jig and measure it for yourself and then decide if it is a valid concern or not.

 

[ronsimpson]

TC4428
I think the data sheet indicates the outputs can handle -0.5A for less than 300uS <2% duty cycle.