BQ24031: detecting battery disconnect.

Prabhat Kumar31

Part Number: BQ24031

Hi,

We are using BQ24031 for our application with battery. Does TI has any recommendation on how to detect battery disconnect?

There are two status pins for charge status but datasheet does not talk about battery detection.

over 5 years ago

0 Bill Johns over 5 years ago

TI__Guru 65716 points

Hello
Is the NTC connected to TS pin and removed as with the battery?

0 Prabhat Kumar31 over 5 years ago in reply to Bill Johns

Prodigy 195 points

Hi,
NTC is connected to TS pin but not removed with the battery. NTC is not removal from the board.

0 Raheem over 5 years ago in reply to Prabhat Kumar31

TI__Mastermind 21590 points

Hello Prabhat,
When the battery is absent, the capacitor on the BAT pin is charged and discharged. When the voltage on the capacitor drops below 4V, the device starts to charge and when the voltage is 4.1V, charging is stopped. This causes the STAT1 and STAT2 pins to oscillate from high to low due to the charge and discharge of the BAT capacitor.

0 Prabhat Kumar31 over 5 years ago in reply to Raheem

Prodigy 195 points

Thanks Raheem,
Can we use state of STAT1 and STAT2 pins to detect battery disconnect/removal? How fast are they oscillating when there is no battery connected?
What will be the optimal way to detect battery disconnect?

Thanks
Prabhat

0 Raheem over 5 years ago in reply to Prabhat Kumar31

TI__Mastermind 21590 points

Prabhat,
There is a deglitch time of recharge is typically 22.5ms so there would be a toggle with that duration. However, this can also happen when the battery is present but not with back to back pulses as the battery itself won't discharge as fast. Is there any reason why you require notification of battery absent?

0 Prabhat Kumar31 over 5 years ago in reply to Raheem

Prodigy 195 points

In our application, we have a requirement to able to tell when battery is absent/removed from the device. Any recommendation?

0 Raheem over 5 years ago in reply to Prabhat Kumar31

TI__Mastermind 21590 points

Hello Prabhat,
Do you have a MCU in your application?

0 Prabhat Kumar31 over 5 years ago in reply to Raheem

Prodigy 195 points

Hi Raheem,
No, we have a processor from NXP imx6ul.

0 Raheem over 5 years ago in reply to Prabhat Kumar31

TI__Mastermind 21590 points

Prabhat,
When the battery is absent, the device charges and stops charging due to the capacitor on the BAT pin being charged and discharged. This will cause toggling on the STAT pins. Can your processor read the toggling on the STAT pins as battery absent?

0 Prabhat Kumar31 over 5 years ago in reply to Raheem

Prodigy 195 points

Hi Raheem,

Yes, we can read toggling on the STAT pin when battery is absent. We have noticed that toggling frequency (1-3Hz) varies among different PCB boards (tested on 3 boards so far). We don't have enough confidence whether this will work all the time. If this is the only way to go then we will have to do more testing .

Thank you for all your help.

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BQ24031: detecting battery disconnect.