Patent ID: 8508279

Claim:
A semiconductor device comprising: a plurality of switching elements that are connected via a low-pass filter respectively to a plurality of batteries connected in series, and that select any one of the plurality of batteries connected in series; a first buffer amplifier that is structured to include a transistor driven by power supply voltage supplied from the plurality of batteries connected in series, and to which voltage of one end of a battery selected by the switching elements is inputted, and that has an input impedance of a magnitude that limits current that flows from the low-pass filter to the switching elements; a second buffer amplifier that is structured to include a transistor driven by the power supply voltage, and to which voltage of another end of the battery selected by the switching elements is inputted, and that has an input impedance of a magnitude that limits current that flows from the low-pass filter to the switching elements; a level shifter that is driven by the power supply voltage, and that outputs a difference between a voltage outputted from the first buffer amplifier and a voltage outputted from the second buffer amplifier; a boosting section that boosts the power supply voltage to a voltage value for operating, in a saturated region, the transistor included in the first buffer amplifier and the transistor included in the second buffer amplifier; and a short circuiting element that short-circuits an input side and an output side of the boosting section on the basis of a control signal.