LM74912-Q1:

Artem Dovgal

Part Number: LM74912-Q1
Other Parts Discussed in Thread: LM74930-Q1

Tool/software:

Hello!

I'm working with the LM74912-Q1 ideal diode controller in a high-side switch application. By default, it blocks reverse current using its built-in gate control logic. However, for my use case, I want to allow reverse current flow under certain conditions — essentially using the external MOSFET as a bidirectional switch, not as an ideal diode.

My idea:

Insert a resistor between the C pin and the MOSFET drain
Add an external N-MOSFET as current sink from the C pin to GND - when current sink enabled - it would allow me to artificially create a condition where V_A (source) > V_C (gate), turning on the MOSFET manually and allowing reverse current

Will it work?

BR,
Artem

2 months ago

0 Shiven Dhir 2 months ago

TI__Mastermind 46660 points

Hi Artem,

Please have a look at LM74930-Q1 which has a dedicated MODE pin and can allow reverse current flow when you want.

Regards,

Shiven Dhir

0 Artem Dovgal 1 month ago

Prodigy 30 points

Hi!
I found that the LM74930-Q1 is currently out of stock at all major distributors. Could you please suggest an alternative controller or solution with similar functionality?

Thank you.

0 Shiven Dhir 1 month ago in reply to Artem Dovgal

TI__Mastermind 46660 points

Hi Artem,

We have some units available for evaluation purposes on TI.com

With similar functionality, we donot have a device.

Regards,

Shiven Dhir

0 Artem Dovgal 1 month ago

Prodigy 30 points

Hi,
Thank you for your previous responses.

Additionally, I’d appreciate your opinion on a potential workaround: manipulating the A and C pins of the LM74930-Q1 to control the external MOSFET—specifically to allow reverse current flow or to operate the device more like a switch rather than a traditional ideal diode. Do you see any issues with this approach or have any recommendations?

0 Shiven Dhir 1 month ago in reply to Artem Dovgal

TI__Mastermind 46660 points

Hi Artem,

A and C pins manipulation might be complex, we have a MODE pin for it. Why not use that?

Regards,

Shiven Dhir

0 Artem Dovgal 1 month ago in reply to Shiven Dhir

Prodigy 30 points

Apologies for the confusion — my question was actually about the LM74912-Q1. I'm interested in whether it's possible to manipulate the A and C pins to control the MOSFET’s behavior. Specifically, I’d like to emulate the "MODE" functionality by introducing an artificial voltage drop (around 0.5–0.6 V) between the A and C pins.

0 Shiven Dhir 1 month ago in reply to Artem Dovgal

TI__Mastermind 46660 points

Hi Artem,

I am afraid if this is achievable.

Regards,

Shiven Dhir

0 Artem Dovgal 1 month ago in reply to Shiven Dhir

Prodigy 30 points

I've attached the schematic diagram.

0 Shiven Dhir 1 month ago in reply to Artem Dovgal

TI__Mastermind 46660 points

Hi Artem,

It can have certain design complications in some corner cases. I would not advise this.

Regards,

Shiven Dhir

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LM74912-Q1: