bq24156A: What is the purpose and functionality of the Special Charger Voltage?

Special Charger Voltage is our VIN dynamic power management (DPM) threshold. Essentially, this feature controls charge current with a voltage controlled current source. The VIN DPM threshold is an input voltage regulation loop that monitors the VIN power supply. If the charger requests more current than what the power source can supply, the source voltage will start to crash. The VIN DPM will see that the voltage is collapsing and will cut back on the charge current to ensure that the input power source will not fall below the programmed VIN DPM threshold. The main benefit of this loop is that it will extract as much current as the input power source can supply without crashing the source below the programmed VIN DPM threshold.