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bq24074 - charge issue

Alejandro Barajas
Prodigy 20 points
Other Parts Discussed in Thread: BQ24074

Some time ago i designed a pcb with the bq24074 to charge a battery of 2100 mah 3.7 V, it charged at first but after a while the chip failed to charge batteries and i put on new designs integrated with the load but it apears to not work anymore, i tested the same values in the evaluation board and it charges the battery to (4.1 V - 4.3V) but in my design it doesnt even start it only stay in the value with some external power sorce but it doesnt charge.

I have the next values: 

Pin 1 - 10k thermistor (i tried to change to a static 10k resistor)

Pin 2 & 3- Go to the positive battery terminal, 4.7uF to ground

Pin 4 - CE ground

Pin 5 - EN2 go to the output

Pin 6 - EN1 go to ground

Pin 7 - Floating

Pin 8 - ground

Pin 9 - Floating

Pin 10 & 11- to the load and a 4.7uF cap to ground

Pin 12 - ILIM, tied to a 1.13k resistor to ground

Pin 13 - IN 5V input 2 A power supply

Pin 14 - TMR - 46.4k resistor to ground

Pin 15 - 4.12 k resistor to ground

Pin 16 - 1.13k resistor to ground

Pin 17 - EP ground 

also it doesnt charge in the new design even with the load off

  • 0
    TI__Expert 7730 points

    You mentioned that the chip was charging normally at the beginning, so did you try replacing the IC on the board to check if the IC is still good? Do you still see correct VOUT? If for some reason the IC is burnt, then the schematic and layout of the board need to be reviewed. Can you share the schematic first?

    Thanks,

    Wenjia

  • 0 in reply to Wenjia Liu
    Prodigy 20 points

    This is the shcematic, i cant replace the ic so easy so i cant realy tell if it desnt work anymore, y can see a good VOUT in the 10 pin its like 4.3V even with no battery present, the bat pin if the battery is not present goes crazy it doesnt have a static voltage.