BQ25703AEVM-732: BQ25703 CELL BATPRESZ not going Low for Battery Removal

Babar Khan

Part Number: BQ25703AEVM-732
Other Parts Discussed in Thread: BQ25703A

I am using BQ25703A for the battery Charger for 5*AA NiMH battery Pack.

When i remove the battery pack the CELL_BATPRESZ does not fall to below 15% of REGN. Datasheet Specify's on page 16.

The Charger does not set the Charge current to 0 when bettery has been removed and BATFET is ON causing the charge Voltage present at VBAT connector.

regards

Babar

over 7 years ago

0 Wang5577 over 7 years ago

TI__Guru 56650 points

Why do you think the CELL_BATPRESZ will fall to below 15% of REGN When you remove the battery pack?

Also, CELL_BATPRESZ is an input pin not output pin.

0 Babar Khan over 7 years ago in reply to Wang5577

Prodigy 205 points

Hi Wang

The datasheet specify's the following:

0 Wang5577 over 7 years ago in reply to Babar Khan

TI__Guru 56650 points

CELL_BATPRESZ is an input pin. The spec table gives the input signal voltage range. The pin description's "I" means an input put signal for bq25703A. External signal pulls CELL_BATPRESZ pin to indicated battery removal to bq25703A. Not bq25703A indicates the battery status.

0 Babar Khan over 7 years ago in reply to Wang5577

Prodigy 205 points

Hi Wang

This means that external battery removal detection needs to be implemented to alert BQ25703A. Right?

secondly i would like to have default charge current set if power source is present and Battery is not fully charge without system/Host to be switch On.

regards

Babar

0 Wang5577 over 7 years ago in reply to Babar Khan

TI__Guru 56650 points

Right. This means that external battery removal detection needs to be implemented to alert BQ25703A.

bq25703A is a host control charger and cannot set default charge current by itself.

Power management

Power management forum

BQ25703AEVM-732: BQ25703 CELL BATPRESZ not going Low for Battery Removal