LM74700-Q1: ORing application with different input voltage ranges

JasonT

Part Number: LM74700-Q1
Other Parts Discussed in Thread: TPS25947, TPS2663

I would like to use the ORing solution shown in Figure 14 of TI document SLVAES2 (Six System Architectures with Robust Reverse Battery Protection Using an Ideal Diode Controller).

Referencing this figure, VIN1 in my application is 6-11V and VIN2 is 5-24V. I want VIN1 to be disconnected when VIN2 is present, but it looks like if VIN2=5V and VIN1=10V (for example) then the Q1 body diode will conduct even if U1 is disabled.

If this is correct then I can change to the topology shown in Figure 15, which I had avoided due to requiring extra board space and higher quiescent current.

Thanks for any feedback - Jason

over 5 years ago

0 Rakesh over 5 years ago

TI__Guru** 107731 points

Hi Jason,

Thanks for reaching out!

You need to use configuration as per Figure 15.

Can you share some more information on your system requirement. Do you need auto-qualified device ? what is the max current in each of the path?

Best Regards, Rakesh

0 JasonT over 5 years ago in reply to Rakesh

Intellectual 280 points

Thanks. We don't need an auto-qualified device. This is for a wearable device that uses a primary battery with secondary power input. Max load is about 20W for either path.

0 Rakesh over 5 years ago in reply to JasonT

TI__Guru** 107731 points

Hi Jason,

Thanks for the details.

Please look at TPS2663 (fig 53 in the datasheet) or TPS25947 parts. These looks to be better fit for your needs.

Best Regards, Rakesh

0 JasonT over 5 years ago in reply to Rakesh

Intellectual 280 points

Thanks Rakesh,

I ended up regulating the wide-range input prior to the ORing logic to solve the problems created by the different input voltage ranges, so the circuit referenced in my original post should work well for us.

Jason

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LM74700-Q1: ORing application with different input voltage ranges