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LM5069 Reverse current AND Reverse Voltage Protection

peter wang
Prodigy 60 points
Other Parts Discussed in Thread: LM5069EVM-627, LM5069

Hi, 

I've read snva673 and snva683, but I found if Vin is reverse in snva673 circuit would cause a reverse current from Vout to Vin through D1.

How can I solve this problem using snva673 and snva683 circuit ?

Thanks for reading.

Best Regards, Peter.

  • 0
    TI__Genius 12380 points
    Hi Peter,

    I don't see the "D1" in snva673 you referred to, but I would suggest ordering the LM5069EVM-627 so you can see in-hand the functionality:
    www.ti.com/.../lm5069evm-627

    Also, we have a user's guide for this EVM which includes tested waveforms of its behavior:
    www.ti.com/.../slvuaa1.pdf

    Thanks,
    Alex
  • 0 in reply to Alex Triano
    Prodigy 60 points

    Dear Alex, 

    Thanks for your reply, 

    I've read LM5069EVM-627 , but the same question confused me.

    I apologize for not making my question clear, even to mislead you.  Allow me to respond as follows:

    1. I want to resolve the reverse voltage problem, so I read the SNVA683 and LM5069EVM-627.

    2. Then I found another question, the question is that when Vin and Vout are both positive but Vout > Vin (like battery and super capacitor application),

    either SNVA683 nor LM5069EVM-627 can't block the reverse current. (Am I right ? )

    So I continue reading SNVA673 which can active block reverse current.

    http://www.ti.com/lit/an/snva673/snva673.pdf 

    But the reverse voltage would make trouble because D1.

    D1 in snva673 page3. Figure 2.

    Thanks for reading and reply again, 

    Best regard.

    Peter

  • 0 in reply to peter wang
    TI__Genius 12380 points

    Hi Peter,

     

    Now I understand your question. I'm not aware of a reverse polarity + active reverse current detection circuit for the LM5069.

     

    Edit:

    We have this reference design:

    which uses the LM5069 (with reverse polarity protection) as the front end, and then connects to the LM5050 for reverse current protection.

     

    This may be the most straightforward and reliable solution. The LM5050 is in a very small package, so the solution size should be comparable.

     

    Thanks!

    Alex

  • 0 in reply to Alex Triano
    Prodigy 60 points
    Dear Alex,

    Thanks for your support again.
    Maybe use 2 ICs is the simplest way to solve this problem.
    Thanks a lot.