BQ24725AEVM-710: Output current limited to 500mA at 1.2V

Abel R.

Prodigy 80 points

Part Number: BQ24725AEVM-710

Tool/software:

Hello,

I'm evaluating the BQ24725AEVM-710 for charging one cell Ni-MH battery.

The input Voltage is 5V (I have modified the ACDET resistor accordingly) and the SYSTEM output is not used.

When setting the output voltage at 1500mV and current at 1024mA, I'm still seeing roughly 500mA maximum current.

I noticed when rising the output voltage above 2500mV the maximum output current limit start to work properly.

I think I've checked everything but I still haven't found the reason why it's not able to deliver more than 500mA at 1500mV output.

Could you please check if I've missed something?

I can share some waveforms if necessary.

Thank you very much!

over 1 year ago

0 Christian Moyer over 1 year ago

TI__Mastermind 39451 points

Hello Abel,

Abel R. said:
The input Voltage is 5V (I have modified the ACDET resistor accordingly)

What resistor values are you using?

Did you change anything else on the EVM?

Best Regards,

Christian.

0 Abel R. over 1 year ago in reply to Christian Moyer

Prodigy 80 points

Dear Christian,

thanks for the quick reply.

I've only installed 7.5K (R15) and 10K (R14) for ACDET and 62K (R22) and 10K (R20) for ILIM.

I've also disconnected the Battery MOSFET.

ACDET Threshold is correctly disconnecting the ACFET at VIN=5.4V

ILIM should limit at 2.3A.

Thank very much for your support!

+1 Christian Moyer over 1 year ago in reply to Abel R.

TI__Mastermind 39451 points

Hello Abel,

This is related to the battery LOWV charge current. If you need the charge current to be higher at below 2.5V, you can decrease the charge current sense resistor to 5mohm, this will clamp the LOWV charge current to 1A instead.

Best Regards,

Christian.

0 Abel R. over 1 year ago in reply to Christian Moyer

Prodigy 80 points

Hello Christian,

I did missed this constraint. Unfortunately limiting even to 1A will not satisfy our requirements.

We will evaluate other options. Could you please suggest a similar alternative?

Thank you very much for your support.

Best regards,

Abel.

Power management

Power management forum

BQ24725AEVM-710: Output current limited to 500mA at 1.2V