Maximum Power Point Tracking (MPPT) Regulation Loop Set-Point Pins. The input voltage regulation loop regulates charge current, providing maximum power charging in the presence of a power limited source such as a solar panel. A resistor divider is placed from the input supply to MPPT, FBOC and ground. These pins are used to program the input voltage regulation loop as a percentage of the input open circuit voltage. If the input voltage falls below the programmed percentage of the open-circuit voltage, the MPPT loop will reduce charge current to maintain the target maximum power point voltage at DCIN. If the input voltage regulation feature is not used, connect FBOC to INTVCC