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EMB1499Q: CELLPLUS range

Massimo Tucci
Prodigy 180 points
Part Number: EMB1499Q

In some applications we have problems in charge mode, because the wire adds up to 1.5 volt to the cell voltage, even with a 2-3A only. It is not possible to make a better connection. The internal circuit of 1499q properly stops charging, but we would like extend the range. The component involved are R1,R3,R4,C3 (1402 board), Let's try to modify R3 to 1.5K (1k org) without modifications. Do you have you a suggestion or workaround?

Thanks and bst rgds

Massimo

  • 0
    TI__Genius 17370 points

    Hi Massimo,

    Can you clarify the issue? Do you mean there is 1.5V voltage drop due to IR drop in the wire or why does it add 1.5V to the cell? 

    Regards,

    Taylor

  • 0 in reply to Taylor Vogt
    Prodigy 180 points

    Hi Taylor

    In some situations, in charge mode, the value on CELLPLUS can reach 5.7/5.8V (4.2cell+1.5/1.6wire) and the IC 1499 stop the charge for Overvoltage. The threshold Vovp, in IC mounted is 5.2, between 4.5min to 5.5 typ, but not enough. I would like to stop the charge mode with a slightly higher voltage ... 5.8-6.0 V not 5.2 actually.

    Note: for example with LiFePo4 cells the problem is not there because the upper threshold is 3.65, with LiPo 4.25 it is.

    tks MaxT

  • 0 in reply to Massimo Tucci
    TI__Genius 17370 points

    Hi Massimo,

    I think its better to work on reducing the voltage addition from the wiring if you really want the current that high -  like by increase of gauge, less resistive or multiple wires. We would not recommend modifying 1k series resistor, as that would be at your own risk to validate.

    Regards,

    Taylor

  • 0 in reply to Taylor Vogt
    Prodigy 180 points

    Hi Taylor,

    yes I know, but in some situations it is not possible to add or change the wire!

    I am looking for a workaround to shift the Vovp threshold from 5.2 close to 6.0 V.
    The functionality of this narrow threshold is not clear.

    Note: for the current it appears to me that it is not possible to go below 2A as previously discussed ...

    Tks & bst rgds

    MaxT

  • 0 in reply to Massimo Tucci
    TI__Genius 17370 points

    Massimo,

    I understand but this is a very old part that we would not recommend customizing the external circuit unless you are willing to validate it. The threshold gives a range at which it could trigger and typically for Li-ion we are surprised to see anyone needing to move the threshold beyond 5V since typ cell is 3.7-4.2V.

    Regards,

    Taylor