BQ27421-G1: Using BQ27421-G1 together with BQ25606

Jaemann Park

Part Number: BQ27421-G1
Other Parts Discussed in Thread: BQ25606, BQ27426

I would like to us BQ27421-G1 together with the battery charger BQ25606.

I have two questions:

1. Would using the BQ27421-G1 negatively affect the charging in any way?

2. Would it be correct to connect the SRX pin of BQ27421-G1 to the BAT pin of BQ25606?

3. Our device draws up to 4A (continuous) from the battery. Will the BQ27421-G1 provide accurate readings?

Thank you in advance.

over 5 years ago

0 Kang Kang over 5 years ago

TI__Mastermind 24870 points

Hello Jaemann,

The bq27421 cannot handle 4 amps continuous with the integrated sense resistor.

I would recommend you check the bq27426.

0 Jaemann Park over 5 years ago in reply to Kang Kang

Prodigy 30 points

Hi Kang,

Thanks for your reply.

On pg. 4 (Pin functions) of the bq27426 datasheet, it says that the Coulomb counter expects a 10 mΩ sense resistor and the fuel gauge is precalibrated for a standard 10 mΩ resistor.

However, the V_SR of the integrating ADC (on pg. 6) is 25mV which implies that the maximum current that does not saturate the ADC is 2.5A.

Am I misunderstanding something?

0 Kang Kang over 5 years ago in reply to Jaemann Park

TI__Mastermind 24870 points

No, this integrated sense resistor can only handle 2.5 amps.

Power management

Power management forum

BQ27421-G1: Using BQ27421-G1 together with BQ25606