BQ25606: Problem with BQ25606 ICs when use three of them

tariq alrefai

Prodigy 10 points

Part Number: BQ25606

Tool/software:

Hello Everyone,

I am designing a Li-ion battery charger with three battery compartments.

I have split the three batteries and used three BQ25606 ICs.

I have set the charging current to 900mA using Rch, and the current limit to 1.1A, for each independent charger, and here comes my problem, the input current for all the chargers (in charging) dose not exceed 900mA for all the chargers, which is not supposed to.

From my understanding, if I connected them in different voltage busses, each charger should limit itself to 900mA.

Please see the below schematic for my circuit:

over 1 year ago

0 Michael Emanuel35 over 1 year ago

TI__Mastermind 40635 points

Hello,

What is the applied battery voltage at this time? If the battery is in pre-charge or close to full charge the charge current will be less.

Regards,

Mike Emanuel

0 tariq alrefai over 1 year ago in reply to Michael Emanuel35

Prodigy 10 points

Hi Mike,

Thanks for your replay.

The voltage applied by the battery is way less than its full charge, it is approximately 3.7V ~ 3.8V

0 Michael Emanuel35 over 1 year ago in reply to tariq alrefai

TI__Mastermind 40635 points

Hello,

These are buck chargers, if you charge at 900 mA the input current will be less than 900 mA as the voltage is stepped down while current is stepped up.

Regards,

Mike Emanuel

Power management

Power management forum

BQ25606: Problem with BQ25606 ICs when use three of them