BQ25618: Q1 FULLON

Toshiro Imi

Expert 7170 points

Part Number: BQ25618

Hi,

Our customer is asking how Q1 FULLON = 1 (Q1 full on) impact on charge current and charge voltage in IINDPM < 700mA.

He plans to charge the battery by Q1 fully on condition in order to minimize power dissipation as much as possible.

Best regards,

over 5 years ago

0 Joel Hernandez II over 5 years ago

TI__Mastermind 25800 points

Hey Toshiro,

There should little impact. However, when IINDPM < 700mA, the IINDPM regulation accuracy will be reduced when Q1 is fully on.

Regards,

Joel H

0 Jeff F over 5 years ago

TI__Guru**** 165886 points

Hi Toshiro,

The Q1 and Q4 FETs each have 2 partitions. For highest efficiency, the charger needs all partitions on. At light load, for improved measurement accuracy by IINDPM (measured by Q1) or charge/termination current (measured by Q4), the charger needs the high current partition off. Q1 FULLON gives Q1 partition control to the host software. The charger auto toggles Q4 partition based on charge current setting.

Regards,

Jeff

0 Toshiro Imi over 5 years ago in reply to Jeff F

TI__Expert 7170 points

Thank you for your suggestion. in summary, Q1 FULLON does not impact on battery charge accuracy i.e. charge current, charge voltage. But in light input current case especially in <700mA IIN, in order to keep IINDPM threshold accurate, Q1 FULLON=0 is needed.

Is my understanding correct ?

best regards,

0 Joel Hernandez II over 5 years ago in reply to Toshiro Imi

TI__Mastermind 25800 points

Hey Toshiro,

That is correct. The IINDPM regulation limit will be impacted @ <700mA when Q1_FULLON is active.

Regards,

Joel H

0 Toshiro Imi over 5 years ago in reply to Joel Hernandez II

TI__Expert 7170 points

thank you. I understand.

Power management

Power management forum

BQ25618: Q1 FULLON