BQ25896: Problem with reading battery voltage while on battery

Maciej Przybecki

Part Number: BQ25896

I implemented BQ25896 as charger and power line for kind of mobile tracking device. Everything works fine according to power line but have weird registry problem.

I'd like to read battery voltage during battery operation. I set REG02 bit 6 and 7 to 1 to turn on ADC and 1s readings.

When I read REG05 while VBUS is connected to external power adapter, everything works fine.

But when I disconnect VBUS and working on battery only the register shows all zero bits which is actually not true.

over 7 years ago

0 Jeff F over 7 years ago

TI__Guru**** 166686 points

Maciej,

In battery only mode, the ADC is only functional if the battery voltage is higher than the MINSYS register setting (REG03 bits1:3). If your change the MINSYS voltage to its lowest setting = 3.0V, the ADC functions down to VBAT=3.0V.

0 Maciej Przybecki over 7 years ago in reply to Jeff F

Prodigy 100 points

Thank you for help! This resolved my problem. Default value is 3.5 and after battery discharge under this value it suddenly stopped working ;-)

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BQ25896: Problem with reading battery voltage while on battery