MP26123 timer problem


I am having problems with the timer pin of this IC.

As described in data a capacitor of 100n should perform a charging stop at 3 hours aprox.

My design is consstently stoping at 90 minutes with 100n capacitor.

I have set a 4.7n and the it stops at 9 minutes aprox which seems correct.
Then I place again a 100n capacitor but yje charge stops again at 90 minutes.

Finally I placed a oversized 1u capacitor but still stops at 90 minutes.

Any idea?
is ther any other issue which could stop the charge at this specific time?

Hi juanandres,

Thanks for your question.
Have you tried monitoring the NTC pin? I’d like to see if the temperature is going above the threshold.
Also, what happens if you place a 50nF cap on TMR? Does it still stop at 90 mins?


Hello Cindy, thanks for your answer.

Yes I also tryed it and the probelm was the same…
Fortunately we have found the problem and it was located at the battery pack. It opened the output mosfets at the described time producing the charger to see 0 current and then finishing the charge. So it is solved and it wsa not related to the MPS IC.

Thanks anyway for your support.