[ Bug ] MP26124 : Timeout decrements during thermal protection


I use this charger to charge battery 4S li-ion, as like the recommended schematic on the datasheet.

But, on some products, I observed a big problem :

  • When the thermal protection is on, the charger stoped. It’s normal.
  • After X hours, the thermal protection disable but… The charger is blocked in timeout mode. And the battery discharge until at 0V without any charge, causing product shutdown when the main supply shutdown (battery is use as secondary supply).

The bug : the timeout roll during thermal protection.

I managed to recreate the bug with a shorter timeout and by heating the thermistor during the defined timeout period.

I find the solution : to drive the pin EN to relauch the charger or disconnect / reconnect battery.
But unfortunely, it’s not possible on my products.

Is this bug known ? What is the solution for my products without control on pin EN ?

According the datasheet, the charger must reset the timeout after thermal error. But it’s not the case.

The only solution realisable that I found, it’s to increase the timeout time. But if the product work during X hours with temperature lower than 10°C, I will get the bug. I don’t take advantage of the load timeout protection…

Or I must by-pass NTC protection and fit in resistor 10k ? But it’s very riskly if the battery is over-heat or same the battery is too cold (problem of lithium-plating)

Thanks in advance

Edit :

  • I use pull-down 0R on pin EN