BQ24295: weird fast STAT LED blinking when charging battery with high Internal resistance

James.Z

Part Number: BQ24295

Hello there!

I'm working on a BQ24295 board with 4 layer PCB. Csys = 2x10uF(X5R 25V), Cbat = 10uF(X5R 25V)

Everything seems OK, but when some battery with long cable or high internal resistance is plugged in, charge is OK at const current stage, after the charg current reachs the termination threshold(default 256mA), BQ24295 will keep charging and STAT LED stat blinking very fast. I add a 100uF capacitor the VBAT pin, the problem is still there.

Also I cannot find any errata info about this chip.

PLEASE HELP.

THANKS

over 6 years ago

0 James.Z over 6 years ago

Prodigy 210 points

the OCV or VBAT is already 4.124V. higher than recharge threshold.

0 iAlejandro over 6 years ago in reply to James.Z

TI__Expert 8130 points

In the first image, C4 seems to have some unwanted solder that is connecting to the cap placed below? Or might be flux?
Also, are you measuring the battery voltage from the battery itself? We recommend on not having a long wire connected from the battery to the charger, as that creates a high voltage difference between the battery and BAT pin.