Semiconductor chip, semiconductor device and battery pack

A semiconductor device includes a control unit which controls charging/discharging of a secondary battery, a bidirectional coupling unit which is electrically coupled to the control unit and through which a charging/discharging current flows, and a protection diode coupled between the control unit and the bidirectional coupling unit. The bidirectional coupling unit includes a discharging power transistor, a charging power transistor reversely coupled in series with the discharging power transistor, and a common drain pad which functions as a drain of the discharging power transistor and further functions as a drain of the charging power transistor. An anode of the protection diode is electrically coupled to the common drain pad. A cathode of the protection diode is electrically coupled to a power supply terminal of the control unit.