FET switch in Battery rail

[cupoftea]

Hi,
Wish to switch the FET on and off fairly quickly, (within a few us at most).
B is better than A, but has more circuitry. Can you think of a good a way as B, but less circuitry?
We have a 5V rail and a 12V rail which can be used.

 

[dick_freebird]

I guess a purpose-made "load switch" piece part is not acceptable?
You don't mention the current requirement although the schematic
values indicate below 1A. Your voltages are modest.

Have you analyzed BOM cost and board area value, against

https://www.digikey.com/en/products/detail/vishay-siliconix/SIP32433BDN-T1E4/16545903

as one example of a wide range integrated load switch (which
also purports to need no auxiliary supply?)

At $1.64 I think you'd be hard pressed to buy the power FET
and all the control pieces ala carte. So what's keeping you
from modern options?

 

[cupoftea]

Thanks, sorry, sometimes load current will be 8A...need low rds(on).