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LM2596: Reverse current protection of LM2596(5V out)

Tai Pham
Prodigy 21 points
Part Number: LM2596

Hi all, I want to ask some questions about Reverse current protection of LM2596(5V out):

1) With Figure 1: I see that Absolute maximum ratings of Pin4 (Feedback pin) is -0.3to25V. When LM2596 is operating if I apply 28V to Point1 by mistake, Are LM2596 and Cout (Rate voltage=10V) damaged ?

2) With Figure 2: when LM2596 is operating if I apply 28V to Point1 by mistake, Are LM2596 and Cout (Rate voltage=10V) damaged ? If this solution is ok, Have any disadvantages with this solution ?

3) Have any application notes or technical documents about Reverse current protection of LM2596 ?

  • +1
    TI__Intellectual 2090 points

    Hi,

    1.Yes this will damage the device and Cout, please avoid;

    2.28V will be blocked by the diode.

    3.You can refer to this document for reference: Reverse Current/Battery Protection Circuits    Protect your system from reverse current

  • +1 in reply to Sirui Zhu
    Prodigy 21 points

    Dear Sirui, thank you for your reply !

    I just want to clarify about the second question that with Figure2 if i apply 28V to Point1, it will be blocked by the diode. So, LM2596 & Cout will be fine. Is that what you mean? Could you tell me have any disadvantages with this solution ?

  • +1 in reply to Tai Pham
    TI__Intellectual 2090 points

    Hi,

    Yes, the diode will protect LM2596 and Cout from damage. However, there will be a voltage drop(~0.6V) on the diode under normal use, and it will lower the whole power efficiency. Also you can use Schottky diode for lower voltage drop, which means it will be more expensive than normal diode.

    Besides, you can take a look at the link I post on the above answer, it introduces other reverse current protection method.

    Regards

    Sirui