BQ2057W: Battery charging current controlling & o/p voltage problem.

Dinesh Jadhav

Prodigy 60 points

Part Number: BQ2057W

I am using this IC to charging 7.2V, 2200mAHr li ion battery.

I m facing following problems

1. O/p vtg. is 9.5V

2. For current controlling, use 0.2 Ohm resistance but when I measure the current, it shows 1.2 A

Attaching schematic to check.

over 6 years ago

0 Bill Johns over 6 years ago

TI__Guru 67196 points

Hello
The schematic would be very helpful, but unfortunately it did not make it something went wrong with the attachment.
Could you try again?

0 Dinesh Jadhav over 6 years ago in reply to Bill Johns

Prodigy 60 points

0 Bill Johns over 6 years ago in reply to Dinesh Jadhav

TI__Guru 67196 points

Hi Dinesh
Check the configuration of below resistors:
1.) R9 (0 ohm) -- should be open
2.) R6 (1k ohm) -- should be open
3.) R7 (100 ohm) -- should be 1k

0 Dinesh Jadhav over 6 years ago in reply to Bill Johns

Prodigy 60 points

Thanks Bill, I have already tried this. Here are some test pics.

0 Upal Patel over 6 years ago in reply to Dinesh Jadhav

TI__Intellectual 1640 points

Hello Dinesh,

Thank you very much for your captures and the data.

For a 7.2V nominal Li-ion battery (2S *3.6V series), the charger would stay in current regulation phase until the battery voltage reaches about 8.4V (voltage regulation phase).
The picture where the output voltage is demonstrated at 7.72V when the battery is connected, and the current being 2.07A, implies that the charger is still in current regulation phase.

Please let us know if you have any other questions.

Thanks and Regards,
Upal Patel

0 Dinesh Jadhav over 6 years ago in reply to Upal Patel

Prodigy 60 points

Dear Upal,

Shall I consider these readings are good?

Because when the battery get fully charged, it shows 9.7V

Today I will conduct few trials & let you know.

Thanks

0 Upal Patel over 6 years ago in reply to Dinesh Jadhav

TI__Intellectual 1640 points

Hello Dear Dinesh,

When the battery is fully charged you should see 8.4V ( if you used default EVM configurations ).

Can you also please confirm if you have added any voltage divider between positive and negative terminal of battery pack to program the voltage regulation?

Please, let me know of latest results.

Thank you very much.

Best Regards,
Upal Patel
Product Marketing Engineer
Texas Instruments Inc
Dallas, Texas, USA

0 Dinesh Jadhav over 6 years ago in reply to Upal Patel

Prodigy 60 points

Hello Upal,

I have used default EVM configurations. If you see the schematic, there is no any divider circuit at battery side.

Thanks
Regards
Dinesh

0 Dinesh Jadhav over 6 years ago in reply to Dinesh Jadhav

Prodigy 60 points

Any updates???

0 Upal Patel over 6 years ago in reply to Dinesh Jadhav

TI__Intellectual 1640 points

Hello Dinesh,
Have you tried to measure the output with an oscilloscope?

Power management

Power management forum

BQ2057W: Battery charging current controlling & o/p voltage problem.