BQ24157: max charge current can't acheive 1.4A

Hey user3578200,

Before we can investigate what you are seeing, can you answer a few questions for me?

1) What is your input voltage set to? (VBUS)

2) What is REG01[7:6] set to? (Iin_Limit)

3) What is the value of Rsns and what is your Battery voltage?

4) What is the value for REG05?


Regards,
Joel H

The bq24157 has safety limit register that limits max charge current and max charge voltage. This host must write to this register before any other I2C write.

Hi Joel

1) What is your input voltage set to? (VBUS)
adpter input 5V

2) What is REG01[7:6] set to? (Iin_Limit)
REG01[7:6]=10

3) What is the value of Rsns and what is your Battery voltage?
Rsns =56mΩ V bat=3.8V

4) What is the value for REG05

Hey user,

So just a few comments:

1) Please make sure you are performing the steps as Jeff stated earlier in response to your post. The Safety Limit Register (REG06) must be written to (0x80 in your case) before you write to any other registers.

2) Based on your response, REG01 is setting the input current limit to 800mA. With that, you may be power limiting. Have you read REG05 to determine the status of the charger? Have you tried lower a lower battery voltage or a higher input voltage (~6V)


Regards,
Joel H

Hi Jeff,

Do you mean that REG06 register must be wrote after POR on both battery and Vbus sides and before any other I2C write? if battery has been assembled on the phone and is hard to be detached, is there any way to change REG06 value of bq24157 by host I2C without battery POR?

Thanks and best regards,
Yang