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TPS61261: Technical issues

Zhonghui Xu
Expert 5445 points
Part Number: TPS61261

Hi team,

I'd like to know if this component protects against inverted polarity in the case of a battery powered application?

Thank you very much for your help.

Best regards,

  • 0
    TI__Genius 9046 points

    Hi Zhonghui,

    Let me check this on bench. Since we do not have stock in lab I applied one. The board is expected to arrive after 1 week. I shall get you feedback later of that.

    -Wenhao

  • 0 in reply to Wenhao Wu
    TI__Expert 5445 points

    Hi Wu,

    Thank you for your help.

    I will wait for your reply.

    Best regards,

  • 0 in reply to Zhonghui Xu
    TI__Expert 5445 points

    Hi Wu,

    Any progress on this case? Have you got the test board?

    Thanks.

    Best regards,

  • 0 in reply to Zhonghui Xu
    TI__Genius 9046 points

    Hi zhonghui,

    Sorry for delay. The package has not arrived site.

    -Wenhao

  • 0 in reply to Wenhao Wu
    TI__Expert 5445 points

    Hi Wu,

    Thank you for your reply.

    I see.

    Best regards,

  • 0 in reply to Zhonghui Xu
    TI__Genius 9046 points

    Hi Zhonghui,

    Thank you very much for your patience. I will test once i have the board on hand.

    -Wenhao

  • 0 in reply to Wenhao Wu
    TI__Genius 9046 points

    Hi Zhonghui,

    I received the board today. If TPS61261 connects with inverted polarity, it cannot work. Place a digital source with 2V/10mA. Per datasheet noted, devices 

    1.J3 connects to positive lead, J1 connects to negative lead. Digital source enters OCL;

    2.J3 connects to negative lead, J1 connects to positive lead. Digital source normally outputs 2V;

    3.Connects positive lead to J4, negative lead to J6. No voltage on Vin, source normally outputs 2V;

    4.Reverse polarity of step "3", digital source enters OCL

    -Wenhao

  • 0 in reply to Wenhao Wu
    TI__Expert 5445 points

    Hi Wu,

    Thanks a lot for your detailed answer.
    So my goal is not to be able to power the unit whatever if the polarity is right or not.

    I only want to know if for any reason the battery is inverted, will it damage the TPS61261?

    The fact that it doesn't provide any output if what I want it will act as a safety for my case. but I'd like to know if it will burn or damage the component?

    Best regards,

  • +1 in reply to Zhonghui Xu
    TI__Genius 9046 points

    Hi Zhonghui,

    The structure of TPS61261 is fixed, the LSFET is NMOS means that when input gets inverted polarity, the current will flow from LSFET's source to drain through its body diode. This means short circuit from GND to SW and this could damage TPS61261. Below is the methods which could help resolve the issue.

    1.One economical way to help protect the device is using a diode between your battery and input of DCDC, shown as below. The maximum avg input current of TPS61261 is 700mA. For a Schottky diode which has forward voltage of ~0.45V, its power dissipation is about 315mW.

    2.Another way is using OR-ing controller from power switching team. Their solution uses MOSFET to enable high efficiency and also keeps fast reverse current protection. You can reach to them for better recommendation.

    3.I can check if we have boost converter with reverse polarity protection in our portfolio. Could you please share me some background information so that I can better find a solution internally? Thank you so much!

    (1)Input voltage range

    (2)Output voltage and load range;

    (3)Why the battery could have reverse scenario

    (4)The volume.

    -Wenhao

  • 0 in reply to Wenhao Wu
    TI__Expert 5445 points

    Hi Wu,

    Thanks a lot for your help.

    Best regards,

  • 0 in reply to Zhonghui Xu
    TI__Genius 9046 points

    Hi Zhonghui,

    Could you please answer my questions i just asked? It would help me find solution. Thanks!

    3.I can check if we have boost converter with reverse polarity protection in our portfolio. Could you please share me some background information so that I can better find a solution internally? Thank you so much!

    (1)Input voltage range

    (2)Output voltage and load range;

    (3)Why the battery could have reverse scenario

    (4)The volume.

    -Wenhao

  • 0 in reply to Wenhao Wu
    TI__Genius 9046 points

    Hi Zhonghui,

    Sorry for delay, i checked internally and we do not have such a device. 

    -Wenhao