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TPS25983: Looking for options to externally modify trip current like with TPS25985

Martijn Meijer
Prodigy 30 points
Part Number: TPS25983
Other Parts Discussed in Thread: TPS25982, TPS25985

Hello TI,

I want to use TI  eFuses for my PDM device.
I need the eFuses to have an externally on-the-fly adjustable trip current.
I want to change the trip current using software and a microcontroller.

The TPS25985 has a possibility to use and external voltage to change the trip current between 10 and 60A if I read the datasheet correctly.
I need the same functionality for 2-15A range.
The TPS25982 and TPS25983 have the correct current range, but doesn't look like they have an option to adjust trip current with an external voltage (or another method)
They are resistor adjustable only?


Are there possibilities to use the TPS25982 and TPS25983 for on the fly trip current adjustment using an MCU?
Or are there other devices available with this possibility?

With kind regards,
Martijn

Above is also discussed in ticket CS1985430 in which I was asked to post my question here.

  • 0
    TI__Guru* 79111 points

    Hi Martijn,

    For TPS25982 device we will have to use the way of adjusting of resistors only. We can not force voltage on ILIM pin. Other way possible is by injecting current into pin but that is not thoroughly tested. This app note can share some insights https://www.ti.com/lit/an/slvaf94/slvaf94.pdf

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 30 points

    Hi Kunal,

    Thanks for the reply.

    Are there other parts like the TPS25985 that are adjustable with external voltage or other method? Or is the TPS25985 the only part currently available with that option? If so, is there a part in the making with that same option for a 2-15A range?

    Regards,
    Martijn

  • 0 in reply to Martijn Meijer
    TI__Guru* 79111 points

    Hi Martijn,

    Unfortunately, right now there is no part like this in lower current range. We generally do not see requirement like these. We will update you if any plans for such part.

    Can you show me where in TPS25985 it is mentioned that trip current can be adjusted by forcing voltage?

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 30 points

    Hi Kunal,

    That's a shame to hear.
    If you open the TPS25985 datasheet, go to page 4, Table 6-1 pin functions (continued) and look at the IREF pin.

    Reference voltage for overcurrent, short-circuit protection and active current
    sharing blocks. Can be generated using internal current source and resistor on
    this pin, or can be driven from external voltage source. Do not leave floating


    Furthermore
    If you go to page 7, table 7-5 Electrical Characteristics (continued) and look at OUTPUT CURRENT MONITOR AND OVERCURRENT PROTECTION (IMON)

    You can see at IOCP Steady-state overcurrent protection (Circuit-Breaker) threshold
    That the threshold changes with different Viref voltages (between 0 and 1.2V)


    If this chip does what the datasheet implies, I should be able to set the breaker current on the fly using an MCU DAC.
    This is what I'm also looking for with chips like TPS25983 and TPS25982.

  • 0 in reply to Martijn Meijer
    TI__Guru* 79111 points

    Hi Martjin,

    Sorry for asking that. I am not an expert on TPS25985 so just thought of asking you as I was not aware of this functionality. Yes TPS25985 can be used for adjustable trip limit by using external voltage. And I can confirm that TPS25983 and TPS25982 can not be used like this.

    We take your feedback and will look into the possibility of implementing this in future lower current range devices. 

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 30 points

    That is too bad. Thanks for the information.
    One last question.
    Would I be able to use a precision digital potmeter like AD5270BCPZ-20-RL7 to set the current of the TPS25983?

  • 0 in reply to Martijn Meijer
    TI__Guru* 79111 points

    Hi Martjin,

    Yes digital pot can be used to set trip current of TPS25983.

    Regards

    Kunal Goel