BQ25071: Reverse polarity detection?

Steve Fenwick1

Part Number: BQ25071
Other Parts Discussed in Thread: BQ25170,

Client wants to be able to make LiFePO4 cell (likely 18650) field-swappable. If the user inserts the battery the wrong way around and tries to charge it with this charger, will the charger prevent charging?

Thanks!

over 3 years ago

0 Nick Brylski over 3 years ago

TI__Mastermind 19195 points

Hello Steve,

If you insert the battery the wrong way the device may be damaged. The absolute max rating on the BAT pin is -0.3V. If this happens charging is not possible.

I would suggest you check our new IC, bq25170, as a lower cost alternative.

https://www.ti.com/product/BQ25170

Best regards,

Nick

0 Steve Fenwick1 over 3 years ago in reply to Nick Brylski

Prodigy 250 points

Is the BQ25170 any better for reverse battery protection? It looks similar to the BQ25071 in that regard.

Best, Steve

0 Nick Brylski over 3 years ago in reply to Steve Fenwick1

TI__Mastermind 19195 points

Hello Steve,

You can add in reverse polarity protection by adding in a FET in the battery path. We have an app note on this here: www.ti.com/.../slva139.pdf

The bq25170 is similar to bq25071, connecting battery backwards will damage IC.

Best regards,

Nick

Power management

Power management forum

BQ25071: Reverse polarity detection?