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TPS25921AD efuse IC

sudhanshu bajpai
Prodigy 175 points

Hello, 

I am using this E-Fuse in my design as a current limiting IC, My system is basically a access control system, basically the module use to provide output supply of 12 V and 5 V to reader, so during the output supply short i.e. the 12 V/5V, the E-Fuse IC will limit the current so that the module wont experience the short circuit and it will keep continuing working.

how ever this module can only get max 1 Amp current and if i design my circuit using e-Fuse IC minimum mentioned current limiting value is 400 mA so in board two ports are there hence in shorting condition it will reach to 800 mA + board supply it will cross the 1 Amp limit and voltage will drop.

so with this IC can i limit current till 300 mA or 250 mA???

  • 0
    TI__Intellectual 2980 points

    Hello Sudhanshu,

    Thanks for this post.

    You can set the device current limit even lower than the 0.4A, the device will as expected but  the accuracy of the current limit is lower as you set the lower current limit. Please refer to the figure Figure 11. Current Limit Accuracy vs Current Limit in the data sheet.

    For example if you set the current limit to 300mA, you can expect the actual current limit > +/-20%  of this value,  i.e. <240mA to  >360mA.

    Please let me know if you have further question.

    Best Regards

    Dinesh

  • 0 in reply to Dinesh Kumar6
    Prodigy 175 points

    Hello Dinesh,

    In my case I have one module which consist two current limiting IC and I need to perform the short circuit test, so in my design I set the current limit to 400 mA ( 39 K-Ohm), however there is the limitation from the power source that maximum 860 mA can be provided to this module.

    if both the current limited output will be short total 800 mA would be the consumption (there will be auto retry functionality will work so continuously we wont get 800 mA but still would be boundary case)+ module's current consumption i.e. 200 mA, so it is exceeding the limit. During Testing I have experienced the failure only once after continuous 4 hour short circuit testing.

    So I was thinking to reduced it to 35.7 K-Ohm i.e. to limit 368 mA or 31.7 k-Ohm to limit 322mA -/+ 20 % (257 to 386 mA)....

    In my design one IC should at least provide 250 mA, so 31.7 K would be the good enough value for me..

    I was afraid because in datasheet it is not mentioned whether we can go for lower value or not

  • 0 in reply to sudhanshu bajpai
    Prodigy 175 points
    Thank you very much valuable reply