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Auto switching for LTC4413

Hi Team,

I've posted a thread here. But no reply so far. So I am posting it once again.
I am using LTC4413 in one of our projects.

I have 2 battery sources primary battery and secondary battery ranging from (2.7V to 4.2V).
I hope 2.6A is the maximum continuous load current through each MOSFET. If so what is the significance of Ioc?.
I want to drive a current of about 2A to the load through this IC.
I hope when both ENBA and ENBB are connected to the ground (a voltage less than 400mV VENBIL) the battery voltage with higher voltage will be fed to the output.
Please correct me if I am wrong.
I want my primary battery to power the load when it is in the range of 3V to 4.2V.
For that, I am planning to set a voltage divider from the primary battery to the ENBB pin such that the voltage at the ENBB pin will be higher than 600mV (VENBIH) so that the secondary battery is disabled and when my primary battery goes below 3V the value of the voltage divider will be lease than 400mV (VENBIL) so that battery with higher voltage will be fed to the load.

Is my configuration correct?.
Will it arise any issue?.
OUTA and OUTB will be shorted together.
Is there any other ideal diode power mux available with a higher current rating and similar voltage rating?.

  • Hi Shibin,
    For some reason, the system did not alert me about your first thread. Thank you for your patience.

    I was also confused about the current limit rating on this part, and here is what I think is going on:

    The first page of the datasheet says 2.6A is the “maximum forward current.”

    The minimum IOC spec is listed at 1.8A. This is because at production wafer sort, all devices are tested with a 1.9A current, which guarantees that parts will pass 1.8A.

    Since you have a 2A application, you should consider using the LTC4415, which operates in a similar voltage range (1.7V -5.5V), and can work up to 4A.

     

    Let me know if you want to go forward with the LTC4413, and I can answer the other questions you had on it.
    -Aaron

  • Hi Ashapiro,
    Thank you for your reply.
    LTC4415 seems like a good choice.
    If my understanding about LTC4415 is correct, the Voltage at the EN pin must be higher than 840mv to turn the first MOSFET turn on and the voltage at the ~EN pin must be less than 760mV to turn the second MOSFET to turn on.
    So I must set a voltage divider such that the output voltage is greater than 840mV when my first battery voltage is above 3V (like 10K and 3.88K) and another voltage divider to the ~EN pin such that the voltage is less than 76omV when my primary battery voltage is less than 3V so that it can sitch my secondary battery to the load.
    Please correct me is if I am wrong.
    Or is there any other solution I can follow to satisfy my requirement?.

  • Hi Shibin,
    I simulated the circuit that you described, and it seems to behave like you want.

    The secondary battery is passed to OUT, until the primary battery ramps up to ~3V.
    At this point, OUT switches over to the primary battery.
    The STATX# pins show when diode1 and diode2 are conducting.
    When the primary battery ramps down, switchover to the secondary battery occurs when primary battery is ~2.8V (due to hysteresis).
    The sim file is attached so you can experiment.
    4415 EZ 9-29-21.asc

    Have a good day,
    -Aaron