SLUSDF9 June 2020 BQ25790
After the input source is qualified, the charger device runs Input Source Type Detection if AUTO_INDET_EN bit is set (default enabled).
The charger follows the USB Battery Charging Specification 1.2 (BC1.2) to detect SDP/CDP/DCP/HVDC input sources and the non-standard adapters through the USB D+/D- lines. After BC1.2 detection is completed, the BC1.2_DONE_STAT bit is set to 1, an INT pulse and BC1.2_DONE_FLAG are asserted if BC1.2_DONE_MASK = 0. In addition, when USB DCP is detected, the charger initiates adjustable high voltage adapter handshake on D+/D- if HVDCP detection is enabled by the host. The input type might be changed after HVDCP detection is completed.
After input source type detection, the following registers are changed:
After detection is completed, the host can over-write IINDPM registers to change the input current limit if necessary. The charger input current is limited by the lower of IINDPM register or ILIM_HIZ pin (when EN_EXTILIM = 1) regardless of Input Current Optimizer (ICO) setting. When AUTO_INDET_EN is disabled, the Input Source Type Detection is bypassed, and the Input Current Limit (IINDPM) register remains unchanged from its previous value.