LM74700-EP: LM74700-EP with Back to back NMOS fets

certified powerpoint technician

Part Number: LM74700-EP
Other Parts Discussed in Thread: LM7310

Hello,

I want to use LM74700 as an -55C capable ideal diode/ power switch that doesn't cost 2 billion dollars.

When I pull EN low, I want to block current to the load. However, in theTypical application (below), it can't do that because if i pull EN low, current will still flow thru the body diode from VBAT to VOUT.

I believe this is for some kind of RPP but IDK.

I want to use the FETs in the load switch config (NMOS is backwards from d/s typ app), see below. Alternatively I could use one of the b2b configs which prevent reverse current flow.

I dont see a reason why this wouldn't work, but could you confirm whether there are any anticipated issues with my approach?

Best,

Rich Templeton

over 1 year ago

0 certified powerpoint technician over 1 year ago

Prodigy 145 points

Also if b2b config is OK, I want to confirm that Cathode pin should still be connected to LOAD, and not to the common Source/Drain between the 2 NMOS.

I'm somewhat sure it will work either way for Anodes kissing, but not sure that it would work for Cathodes kissing config.

+1 Praveen GD over 1 year ago in reply to certified powerpoint technician

TI__Guru 57737 points

Hi,

Please refer to the e2e FAQ below,

Can LM5050-1, LM74700-Q1 or TPS241x controllers drive two back-back MOSFETs

0 certified powerpoint technician over 1 year ago in reply to Praveen GD

Prodigy 145 points

Thank you.

I ran some sims and realized this part does not do what I thought it would do. I assumed it could function like LM7310 but i was wrong.

thank for your help I will make sure you get extra profit sharing this year

Best

dimitri

Power management

Power management forum

LM74700-EP: LM74700-EP with Back to back NMOS fets