BQ24133EVM-715-15V: BQ24133 Charge Termination

Matthias Krienbuehl

Part Number: BQ24133EVM-715-15V
Other Parts Discussed in Thread: BQ24133

Support Path: /Product/Development and troubleshooting/Search the forums for my problem/

I'm using the BQ24133EVM-715-15V board to develop a charger curcuit for 2 lithium-ion series cells. I configure the board to get following charge settings:

- Viset = 0.191V -> Icharge = 0.96A

- IDPM = 1.9A

- TC = high -> safety timer disable, termination enable

- Vin = 12V

With these settings everything works as it shut except charge termination. I expect charge termination at a current of 0.096A but BQ24133 already terminates charging at 0.45A. I measured voltage over the sense resistor (10 mOhm) and get a correct value. Do you have any explantion for this behaviour? I assume that this behaviour is not in relation with the undercurrent protection feature of BQ24133?

Thank you for your help

Matthias

over 7 years ago

0 Steven Bangdiwala over 7 years ago

TI__Expert 8690 points

Hi Matthias,

How are you approaching the termination threshold? Are you using a sourcemeter and manually changing the voltage to simulate a battery or are you using a real battery and monitoring the charging current?

Regards,
Steven

0 Matthias Krienbuehl over 7 years ago in reply to Steven Bangdiwala

Prodigy 20 points

Hi Steven

I'm using a real battery and monitoring charging current...

I did a additional test with a battery simulator and there termination works well.

Thank you

Matthias

0 Steven Bangdiwala over 7 years ago in reply to Matthias Krienbuehl

TI__Expert 8690 points

Take a look at the waveform on SRN. It could be noisy, making the device go into constant voltage quicker, any noise on the SRN pin may trigger the device to think that the battery is fully charged and terminate early.

Regards,
Steven

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BQ24133EVM-715-15V: BQ24133 Charge Termination