Semiconductor device

A semiconductor device comprising:

• a first external terminal connectable to a positive electrode of a secondary battery;
• a second external terminal connectable to a negative electrode of the secondary battery;
• a third external terminal electrically connected to the first external terminal and configured to output a voltage received from the secondary battery to an outside;
• a fourth external terminal configured to receive a signal from the outside or output a signal to the outside;
• a first integrated circuit including:
• a first power supply terminal;
• a first voltage terminal connected to the third external terminal;
• a second power supply terminal connected to the second external terminal;
• a first signal terminal connected to the fourth external terminal and configured to receive or output a signal;
• a second signal terminal electrically connected to the first signal terminal;
• and
• a first metal oxide semiconductor (MOS) transistor having a drain electrically connected to the first signal terminal, and a source and a gate electrically connected to the first voltage terminal, and
• a second integrated circuit including:
• a third power supply terminal electrically connected to the first external terminal;
• a fourth power supply terminal configured to output, to the first power supply terminal, a power supply voltage generated based on a voltage received at the third power supply terminal;
• and
• a third signal terminal configured to receive a signal from the second signal terminal or output a signal to the second signal terminal, the second integrated circuit controlling charging and discharging of the secondary battery.