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BQ24032A - End of charge problem

Daniel Zilinec
Prodigy 10 points
Other Parts Discussed in Thread: BQ24032A

Hi,

I have 25 PCBs with BQ24032A charger and at cca one half of it is a problem with charge terminating. When the charger is in constant voltage mode, charging current is decreasing and normally will stop at 130 mA ( 1/10 of maximum charging current; R_Iset1 = 470R), but on my problematic boards charger continues in charging even to near-to-zero current and will never stop. Voltage on Iset1 pin is then lower than 250 mV.

This problem is temperature dependent, so boards that have no problem with charge terminating at room temperature will turn to problematic when heated to 50°C.

It can be solved by exchanging BQ by new one, but sometimes is the new one also problematic. All board was hand-soldered in ESD-safe enviroment. Is it possible, that I bought damaged ICs ? I have one year old batch of 20 board with the same design and works well.

 

BQ24032A configuration:

AC - 5V

USB - GND

PSEL - HIGH

CE - HIGH

DPPM - 36k9 to GND (with 100nF)

ISET1 - 470R to GND

ISET2 - GND

TMR - 68k

IC is used only like a charger. PowerPATH functionality is not used.

 

Thank you for your help

 

  • 0
    TI__Guru 56650 points

    Because this problem dependents the ambient temperature , it could be thermal regulation loop controls the charging current. So, the charger is not terminated even the charging current current is lower. Please monitor TMR pin waveform. Are the TMR pin frequency different between good board and bad board?