A reconfigurable DC-DC converter including a controller is disclosed which automatically adjusts the mode of operation (buck mode or boost mode) depending on the system requirements and is able to achieve the maximum efficiency and the lowest inductance current. The method of switching between buck and boost mode allows the converter to operate to 100% duty cycle for buck mode and 0% duty cycle for boost mode. This maximizes efficiency since the buck-boost mode of operation is eliminated and improves the stability and reliability of the system. A converter output voltage is processed and compared to a control voltage to generate buck and boost comparator output signals. The buck and boost comparator output signals are provided to control logic, which generates switch control signals, which are provided to the DC-DC converter to establish buck mode, boost mode, or pass-through mode.