Switching circuit and power supply device

摘要

A switching circuit (100) includes first and second MOS transistors (M1, M2) of the same conductive type. The second MOS transistor (M2) has a drain connected to a first terminal (T1), a source connected to a load connecting terminal (Tout), a gate connected to a gate of the first MOS transistor (M1), and a back gate connected to a source of the first MOS transistor (M1). The switching circuit (100) includes a potential control circuit (Vc) that controls a current flowing between the source of the first MOS transistor (M1) and a resistor connecting terminal (TR) so that the potential of the source of the first MOS transistor (M1) and the potential of the source of the second MOS transistor (M2) are equal. This switching circuit (100) further includes a switching control circuit (CON) that outputs a control signal (Sg) to the gate of the first MOS transistor (M1) and the gate of the second MOS transistor (M2)and controls the operations of the first MOS transistor (M1) and the second MOS transistor (M2).