BQ24070 not charging

Sergey Vladimirov

Expert 1300 points

Other Parts Discussed in Thread: BQ24070

Hi,

I have the following schematics that I use for BQ24070:

Input is 5v, on output i see 4.4v when power supply is connected, but the battery is not charging at all.

I removed the battery and tested VBAT output which gives 0v.

Any ideas what I have to look into?

Battery is LiIon 3.7V, 140mAh

Thanks,

Sergey

over 10 years ago

0 Wenjia Liu over 10 years ago

TI__Expert 7730 points

What is your TS pin connection? It cannot be float. You can either connect a 103AT thermistor or a 10k resistor to the pin.

Thanks,

Wenjia

0 Sergey Vladimirov over 10 years ago in reply to Wenjia Liu

Expert 1300 points

Hi Wenjia,

its connected to a thermistor (pls see datasheet attached).

I was thinking may be Rset resistor is too small and thats why there could be some problem?TSM1A103F34D1RZ.PDF

Cheers,

Sergey

0 Wenjia Liu over 10 years ago in reply to Sergey Vladimirov

TI__Expert 7730 points

Even if the battery is not connected, the voltage on BAT pin should not be zero. Instead, you should see saw wave from 4V to ~4.3V. Please check your board and see if there's any short circuit path at BAT pin.

Thanks,
Wenjia

0 Sergey Vladimirov over 10 years ago in reply to Wenjia Liu

Expert 1300 points

Thanks Wenjia, it was an SMT issue indeed

0 Sergey Vladimirov over 10 years ago in reply to Sergey Vladimirov

Expert 1300 points

Hi Wenja,

To continue this issue, something weird is happening: the battery is slowly charging to 4.2v, but STAT1 and STAT2 are always LOW Does it mean that its always charging in the precharge mode or does it mean that there is a fault?. (Have removed R4 and swapped R6 to 10K)

Any suggestions?

Thanks,

Sergey

0 Wenjia Liu over 10 years ago in reply to Sergey Vladimirov

TI__Expert 7730 points

Sergey,

This is not an expected behavior. What is the charging current? Did you see a current change when the battery voltage exceed the VLOW threshold?

Thanks,

Wenjia

0 lalitha sankh over 10 years ago

Prodigy 40 points

Hi,
I have also used BQ24070 IC for battery management but facing issue like when mains removed this IC should switch on battery so that other components on board should get powered on by Battery it happens only once when mains disconnected, but if we reset the board without mains then none of the components on the Board get powered on by battery.

I feel all the setting related to this IC are not getting stored in its internal memory & every time setting needs to be done

Regards,
Lalitha

0 Wenjia Liu over 10 years ago in reply to lalitha sankh

TI__Expert 7730 points

Can you specify what are the settings you want to store? This device doesn't have customer programmable registers and I believe all the settings are external resistors.

Thanks,
Wenjia

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BQ24070 not charging