BQ24650: Operation cannot be confirmed in my test circuit

SEIJI MIGITA

Part Number: BQ24650

Tool/software:

Dear TI Support

Hello, my name is Migita.

I am currently using the "BQ24650" and am experimenting with the following circuit under the following conditions, using the sample circuit as a reference, but I am not able to charge it properly. (LED3 and 4 do not light up at all)

Is there a problem with the parameters or circuit configuration? Please advise.

1) Solar panel: 5-10V, 2-3W

2) Battery: Li-ion 3.7V 2000mA x 1

Is there any problem with the parameters or circuit? I would appreciate your advice.BQ24650_20250609.pdf

2 months ago

0 Christian Moyer 2 months ago

TI__Mastermind 31946 points

Hello Seiji,

I recommend refering to the BQ24650 schematic checklist:BQ24610_BQ24650_Schematic_Checklist (77).pdf

I see you are missing the 1uF and 10ohm resistor on VCC, Please confirm you have all the required components.

Best Regards,

Christian.

0 SEIJI MIGITA 1 month ago in reply to Christian Moyer

Prodigy 10 points

Thank you for your advice, Christian Moyer.

I added resistors and capacitors and changed the resistance values (shown in red) by referring to "BQ24610_BQ24650_Schematic_Checklist (77).pdf". It seems that charging is occurring, but LEDs 3 and 4 do not light up.

Is this okay?

I would appreciate any suggestions.BQ24650_20250722.pdf

0 Christian Moyer 1 month ago in reply to SEIJI MIGITA

TI__Mastermind 31946 points

Hello Seiji,

Can you measure the STAT1 and STAT2 pins?

Best Regards,

Christian.

0 SEIJI MIGITA 29 days ago in reply to Christian Moyer

Prodigy 10 points

STAT1 is 2V, STAT2 is 2.3V. Also, REF is showing -38mV, is this normal? At this time, the charging power supply is 5V and 600mA.

0 Christian Moyer 28 days ago in reply to SEIJI MIGITA

TI__Mastermind 31946 points

Hello Seiji,

Are you sure the solar panel is supplying 5V? STAT1/STAT2 should be closer to 5V if this is the case.

Best Regards,

Christian.

0 SEIJI MIGITA 27 days ago in reply to Christian Moyer

Prodigy 10 points

Hello Christian,
Thanks for confirming.
Currently, I'm testing it using a power supply instead of a solar panel. The lithium-ion battery I'm charging is 3.7V, so I'm testing it at 5V. Also, isn't the voltage at the REF terminal 3.3V?
Thank you in advance for your help.

0 Christian Moyer 27 days ago in reply to SEIJI MIGITA

TI__Mastermind 31946 points

Hello Seiji,

SEIJI MIGITA said:
isn't the voltage at the REF terminal 3.3V?

Yes, Vref should be 3.3V, if VCC is above(3.65-4V)

Can you try increasing the input supply to 10V?

SEIJI MIGITA said:
STAT1 is 2V, STAT2 is 2.3V.

I'm not sure why STAT1/2 would only be 2V, if it's connected to a 5V input supply.

Can you also try to increase the MPPSET voltage to 5V?

Best Regards,

Christian.

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BQ24650: Operation cannot be confirmed in my test circuit