BQ24072: CHG pin issue

MIT SHAH

Part Number: BQ24072

Hello team,

We are using BQ24072 IC to charge a LI-ion 18650 battery, capacity is 1400mAh.

Kindly find the schematic below :

The CE pin is low.

While the battery voltage is below 4.0V the CHG pin stays low and when the battery voltage exceeds the CHG pin start giving pulses.

About the pulses:

1) On time : 2ms

2) Off time : 19ms

So in our application MCU finds it difficult to understand the exact status of CHG pin.

We tested 10 device and out of 10 three device have issues other 7 is working fine.

Please review the schematic and let me know if i am missing anyting.

Regards,

Mit

0 Raheem over 5 years ago

Hello,

Can you post a scope capture of the fault signal on /CHG.

What VBAT voltage does the issue occur at?

0 MIT SHAH over 5 years ago in reply to Raheem

Dear Raheem,

Thank you for your response.

I did capture the fault waveform on /CHG (Channel 1) and VBAT (Channel 2),

VBAT looks good but due to the /CHG fault signal, I am having issues.

Please explain the reason for it and suggest a solution.

Also FYI, I have tested 10 boards and 7 out of 10 are having no issues. So is it the problem with the chip quality?

Regards,

Mit shah

0 Raheem over 5 years ago in reply to MIT SHAH

Hello,

The fault pin on /CHG should be a 2Hz signal. Can you also plot VIN and ICHG to check that the device isn't going in and out of charging the battery.

0 Raheem over 5 years ago in reply to Raheem

Hello,

Any update here?

0 Raheem over 5 years ago in reply to Raheem

Hello,

I'll close this issue. Please post a response if you have any updates.

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