Other Parts Discussed in Thread: BQ25600, BQ25601, BQ25618, BQ25606, BQ25600D, BQ25616, BQ25619, , BQ25600C, BQ25611D
It was observed that VSYS could not start up normally with some loading on SYS when the battery is not present . This applies for BQ25601, BQ25601D, BQ25606, BQ25611D, BQ25616, BQ25616J, BQ25618, BQ25619, BQ25600, BQ25600D, BQ25600C. The reasons are listed below:
- The input current limit is set to IIN(START) (200-mA typically) internally if the voltage on SYS pin VSYS is less than the VBAT_SHORT.
- The device provides soft-start when system rail is ramping up. When the system rail is below VBAT_SHORT, the input current is limited to the lower of 200-mA or IINDPM register setting. The system load shall be appropriately planned not to exceed the 200-mA IINDPM limit. After the system rises above VBAT_SHORTZ, the device input current limit is the value set by the IINDPM register.
- When the charger is powered up without the battery’s presence, VSYS will start from 0V and the input current is limited. If the SYS load tries to pull more than IIN(START) input current, VSYS may be current-limited so that VSYS can’t start up normally.
- In order to start up VSYS normally, the system loading on SYS pin should be applied after the SYS voltage has been ramped up above VBAT_SHORTZ.