nPM1100 Recharge Issues

We are in the process of the developing a wearable product and we have already developed a series of prototypes, in which one of the components is the nPM1100 but we have encountered the following issue and we did like to know if there is a solution.

The issue comes when recharging and occurs in the following conditions:

- The battery is isolated by the nPM1100 when below VBATBOR (2.5V), but at the same time the Lipo batteries have a voltage cut-off at 2.5V, when this happens the battery goes in open circuit and the voltage across the battery is 0V.

- As the battery voltage is now essentially 0V (due to the circuit protection), the nPM1100 will no longer recharge the Lipo as it thinks it is below the VBATCHARGEMIN (2.1V), but in reality there is nothing wrong with the battery.

We wanted to know how this is solved in other projects as it seems to be a big incompatibility issue.

Thanks for your time.

Parents Reply
  • Hi Andres,

    The circuit looks OK. Here are a few things to try:

    • Let us know where you ordered the battery, and we will order one fore ourselves. We will then try to reproduce the issue.
    • Try setting up nPM1100 EK with your batter and see if anything is different.
    • Try removing the battery monitoring circuit(for example by removing R4.
    • Connect an oscilloscope to VBAT. Capture using a approx. a 10 second window.

    Best regards,

    Håkon

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