After the VBUS_GD bit is set and REGN LDO is powered, the device runs input source detection through D+/D– lines or the PSEL pin. The BQ25600D follows the USB Battery Charging Specification 1.2 (BC1.2) to detect input source (SDP/ DCP) and nonstandard adapter through USB D+/D– lines. The BQ25600 sets input current limit through PSEL pins.

After input source type detection is completed, an INT pulse is asserted to the host. in addition, the following registers and pin are changed:

1. Input Current Limit (IINDPM) register is changed to set current limit
2. PG_STAT bit is set
3. VBUS_STAT bit is updated to indicate USB or other input source

The host can overwrite IINDPM register to change the input current limit if needed. The charger input current is always limited by the IINDPM register.