BQ25120A: possible to charge empty lipo battery with protection circtuit

Coen Lauwerijssen

Part Number: BQ25120A
Other Parts Discussed in Thread: BQ25120

Hi,

We normally use Lipo batteries with build in protection circuits for under/overvoltage/current protection. The undervoltage protection in the battery switches off at 3.0V. We have difficulties charging these batteries when empty with the BQ25120 and also other chargers in the TI range (BQ2515).

Question: should it be possible to use these chargers in combination with lipo batteries with build in battery protection circuit or only use these chargers for batteries without protection circuit?

Regards,

Coen

over 4 years ago

0 Raheem over 4 years ago

TI__Mastermind 21590 points

Hello,

When the battery is empty, the precharge current is used to open the protector. What resistor do you have on the PRETRM and ISET pins?

You're able to use the charger with batteries that have protection and batteries that don't.

0 Coen Lauwerijssen over 4 years ago in reply to Raheem

Prodigy 40 points

Hi Raheem,

PRETERM = 5k

ISET = 4k

ILIM = 500

We set the value also with I2C, but guess that its better to increase the precharge current by modifying PRETERM right?

Regards,
Coen

0 Raheem over 4 years ago in reply to Coen Lauwerijssen

TI__Mastermind 21590 points

Hello Coen,

The I2C command overwrites the precharge current set by the resistor. You can increase the precharge current setting by reducing the resistor and see if this helps with the issue.

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BQ25120A: possible to charge empty lipo battery with protection circtuit