BQ24725A: Charger can not start-up

Doan sang

Prodigy 20 points

Part Number: BQ24725A

Tool/software:

Dear TI team and experts,

I design charger device using part BQ24715A, and I have a problem when start system.

when I plug 12V input (at +12V_OUT) to charger to start up.

If output have no Load, charger ON normally

If output have Load (example 0.7A at +SYS_IN), charger can not enable. Input power supply switch CV to CC.

Note: netname +12V_OUT at input, sorry because name is conflict, before this charger block, I am using filter block, so netname is +12V_OUT

Please view and check for me to find the root cause.

Many thanks & Best Regard.

7 months ago

0 Christian Moyer 7 months ago

TI__Mastermind 31571 points

Hello Doan,

This is the same as: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1464443/bq24725a-charger-off-when-apply-load-immediately

I will help answer on that thread.

Best Regards,

Christian.

0 Doan sang 7 months ago in reply to Christian Moyer

Prodigy 20 points

Hi Christian Moyer,

Link above does no address my issues. It explain problem same as my board.

I want to know how to fix this issues, help startup charger as soon as plug 12V input with have load at output.

Thanks.

0 Christian Moyer 7 months ago in reply to Doan sang

TI__Mastermind 31571 points

Hello Dong,

Do you see any changes if you add the 10ohm VCC current limiting resistor?

Best Regards,

Christian.

0 Doan sang 7 months ago in reply to Christian Moyer

Prodigy 20 points

Hi Christian Moyer ,

I tried but do not see any change.

I think it relate to start-up condition of charger controller. When start-up, It will check load condittion at the output, if load higer one threshold, it will off charger.

However, above is my guess, I am not sure.

Please give me some advise about this problem.

Best regards.

0 Christian Moyer 7 months ago in reply to Doan sang

TI__Mastermind 31571 points

Hello Doan,

Doan sang said:
I think it relate to start-up condition of charger controller. When start-up, It will check load condittion at the output, if load higer one threshold, it will off charger.

I don't see this issue when I use an EVM.

Can you provide your register values when the device is not able to charge?

Best Regards,

Christian.

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BQ24725A: Charger can not start-up