According to an embodiment, the threshold value generation unit generates a setting voltage and converts the setting voltage to a first current. One end of the first resistor is connected to a detection terminal. When a voltage applied to the detection terminal is greater than or equal to a predetermined factor times the voltage of the higher voltage source, the detection unit causes a constant detection terminal input current to flow from the detection terminal to the first resistor. When the voltage at the detection terminal is less than the predetermined factor times the voltage of the higher voltage source, a higher voltage source voltage is outputted to a detection output terminal, while the voltage at the detection terminal is greater than or equal to the predetermined factor times the voltage of the higher voltage source, a lower voltage source voltage is outputted to the detection output terminal.