BQ25703A: Pre-charge function check

peiyq

Expert 1400 points

Part Number: BQ25703A

Hi TI，

We are evaluat bq25703A，we use 2-cell battery in our system.

Could you check if pre-charge can be used when battery is out discharge when using 5V USB type C power input?

Thanks

Pei Yuanqing

over 5 years ago

0 Joel Hernandez II over 5 years ago

TI__Mastermind 25800 points

Hey Pei,

What do you mean by "out disccharge"? Do you mean "over-discharge"?

On this charger, pre-charge occurs when an adapter is present, LDO mode is active, and the VSRN voltage (which is the battery voltage) is < the VSYSMIN voltage (from the SystemMinimumVoltage() register.

Regards,

Joel H

0 peiyq over 5 years ago in reply to Joel Hernandez II

Expert 1400 points

Hi Joel,

Yes,I means over-discharge battery.

Could you double confim if pre-charge can occurs since 2 cell battery is 7.4V while USB input is 5V?

Thanks

Pei Yuanqing

0 Joel Hernandez II over 5 years ago in reply to peiyq

TI__Mastermind 25800 points

Hey Pei,

Yes, pre-charge only occurs when VSRN (VBAT) is < VSYSMIN setting (which is defined by the CELL_BATPRESZ pin) and the EN_LDO bit is active (active by default).

This is regardless of USB input voltage because this is a buck-boost charger.

Regards,

Joel H

Power management

Power management forum

BQ25703A: Pre-charge function check