Buck converter gate drive is unsuitable?

[Faringdon]

We have a 750W Buck sent in by a customer. They want the same , but cheaper. (42vin, 24vout)
We think its gate drive is dodgy (schem 1)
We think schem 2 improves it.
Do you agree?
(LTspice and PDF schems attached.

[f4eru]

why not use a proper gate drive IC, with an UVLO ?

[Faringdon]

Maybe liek in the attached yes, ie, using a very common gate driver, but otherwise, we cant , because of future supply issues.
(LTspice and pdf schem attached)

[T3sl4co1l]

The transformer is better I suppose because it provides some supply to the bootstrap supply, whereas a pure (nonmagnetic) bootstrap driver won't start up, or not reliably anyway.

Solution of course is to use a charge pump type like HIP4080.

Tim

[Faringdon]

The transformer is better I suppose because it provides some supply to the bootstrap supply, whereas a pure (nonmagnetic) bootstrap driver won't start up, or not reliably anyway.

Thanks, yes,  the controller needs to wait for the bootstrap cap to get fully charged via the  output divider before starting up.....but after that its ok though.
Thanks for the HIP4080 , it looks great, ...as you know, there is significant fear at the moment that these kind of chips may become difficult to source.