Semiconductor device

A semiconductor device comprising:

• a resistor comprising a pair of terminals;
• a first circuit configured to amplify a first voltage generated between the pair of terminals of the resistor when a first current flows through the resistor and output a second voltage corresponding to the first voltage;
• a second circuit configured to generate and output a second current corresponding to the second voltage;
• and
• a third circuit configured to generate a first signal in accordance with the second current,
• wherein the third circuit comprises:
• a capacitor including a first terminal and a second terminal;
• a first switch configured to control connection between the first terminal and the second circuit;
• a second switch configured to control supply of a constant voltage to the first terminal;
• a fourth circuit configured to compare a voltage of the first terminal with a first reference voltage and generate a second signal;
• a fifth circuit configured to compare the voltage of the first terminal with a second reference voltage and generate a third signal;
• a sixth circuit configured to generate the first signal by counting the number of changes of levels of the second signal and the third signal;
• and
• a seventh circuit configured to generate a control signal of the second switch from the second signal and the third signal,
• wherein potential of the second terminal is set equal to potential of one of the pair of terminals of the resistor, and
• wherein the third circuit is configured to repeat a sampling operation during which the first switch is turned on and the capacitor is charged with the second current and a holding operation during which the first switch is turned off and electric charge stored in the capacitor is held.

A storage device comprising:

• a power storage body;
• a power supply control circuit electrically connected to the power storage body;
• a microprocessor unit electrically connected to the power supply control circuit;
• and
• a coulomb counter configured to supply a first signal to the microprocessor unit,
• wherein the coulomb counter comprises:
• a resistor comprising a pair of terminals;
• a first circuit configured to amplify a first voltage generated between the pair of terminals of the resistor when a first current flows through the resistor and output a second voltage;
• a second circuit configured to generate and output a second current corresponding to the second voltage;
• and
• a third circuit configured to generate the first signal in accordance with the second current,
• wherein the third circuit comprises:
• a capacitor including a first terminal and a second terminal;
• a first switch configured to control connection between the first terminal and the second circuit;
• a second switch configured to control supply of a constant voltage to the first terminal;
• and
• a fourth circuit configured to output the first signal-corresponding to a voltage of the first terminal,
• wherein one of the pair of terminals of the resistor is electrically connected to the power storage body,
• wherein potential of the second terminal is set equal to potential of the other the pair of terminals of the resistor, and
• wherein the third circuit is configured to repeat a sampling operation during which the first switch is turned on and the capacitor is charged with the second current and a holding operation during which the first switch is turned off and electric charge stored in the capacitor is held.