Low cost mosfet replacement for diode in boost application

[Vindhyachal.takniki]

1. have a boost circuit where:
a) Vin: 8.1V to 12.3V
b) Vout = 12.3V/12.5Amps  (If 12V/12.5A possible then better, but my ckt gives 12.3V, otherwise need to switch to sepic, which is costly and 12.3V is acceptable so took this low cost part)

2. Here is circuit which I will use. Want to replace D2 diode with mosfet since at 12.5Amps even a Schottky will produce lots of heat.




3. I searched for replacement of diode with p channel mosfet like here: https://electronics.stackexchange.com/questions/223935/understanding-an-ideal-diode-made-from-a-p-channel-mosfet-and-pnp-transistors

4. Also looked for N-channel mosfet replacement, found some high side driver like these: https://www.microchip.com/paramchartsearch/chart.aspx?branchID=90102

5. But one doubt is mosfet are bidirectional paths, while diode is single side. So will it create issue in circuit?

6. Any other better way to replace with diode here. Need to change in this circuit only. I know there are sync boost converters also, with mosfets, but expenive or if some low cost alternative available?

[Siwastaja]

You need a thing called "synchronous boost".

It's quite iffy to replace the diode only; you would need a very fast replacement circuit. Instead, normally you do this by picking a different DC/DC controller IC, one which is designed for synchronous boost. It will offer a gate drive signal for your synchronous FET directly!

TLDR: Replace IC1 with a synchronous boost controller which drives two FETs.

Another comment: Get rid of the discrete gate driver Q1/Q5, and just use a driver IC which can drive enough current to your MOSFET(s). At this power level, you shouldn't have problems finding complete integrated controller IC which has enough gate drive oomph so that no external gate driver (IC or discrete) is needed.

[Vindhyachal.takniki]

I think synchronous boost would be better choice.