Semiconductor device and battery voltage monitoring device
A semiconductor device is provided for measuring a voltage of each of plural unit cells series-coupled in multi-stage and configuring an assembled battery. The semiconductor device includes two terminals coupled to two nodes which are electrodes of a unit cell and coupled with other unit cells, and a voltage measurement circuit which measures the inter-terminal voltage between the two terminals. The device also includes a down-convert level shifter circuit which converts the inter-terminal voltage into a low-potential-side inter-terminal voltage based on a ground potential, and a comparator circuit which compares the converted low-potential-side inter-terminal voltage with a predetermined reference voltage. The semiconductor device further includes an up-convert level shifter circuit which converts a low-potential-side shunt control signal based on the ground potential into a high-potential-side shunt control signal, and a switch which short-circuits the two terminals via a resistor based on the converted high-potential-side shunt control signal.
1. A method of measuring voltage of each of a plurality of unit cells series-coupled in multi-stage and configuring an assembled battery, the method using at least one semiconductor device,
wherein the semiconductor device comprises:
a first terminal to be coupled to a first node which is one electrode of a unit cell and is coupled to another unit cell in the unit cells; and
a second terminal to be coupled to a second node which is the other electrode of the unit cell and is coupled to another unit cell,
wherein the method comprises:
measuring an inter-terminal voltage between the first terminal and the second terminal by a voltage measurement circuit;
converting the inter-terminal voltage into a low-potential-side inter-terminal voltage by a first level shifter circuit;
comparing the low-potential-side inter-terminal voltage with a predetermined reference voltage by a comparator circuit;
converting a low-potential-side shunt control signal into a high-potential-side shunt control signal by a second level shifter circuit; and
short-circuiting the first terminal and the second terminal via a first resistor, on the basis of the high-potential-side shunt control signal by a first switch,
wherein the semiconductor device further comprises:
a third terminal to be coupled to the first node; and
a second resistor coupled between the first terminal and the third terminal,
wherein the method further comprises:
converting a low-potential-side sense enable signal into a high-potential-side sense enable signal by a third level shifter circuit;
converting a low-potential-side cell balance enable signal into a high-potential-side cell balance enable signal by a fourth level shifter circuit; and
short-circuiting the third terminal and the second terminal, on the basis of the high-potential-side cell balance enable signal by a third switch, and
wherein the first level shifter circuit comprises:
a voltage-to-current converter circuit operable to convert the inter-terminal voltage into a current value corresponding to the inter-terminal voltage;
a current-to-voltage converter circuit operable to convert the current value into a low-potential-side inter-terminal voltage corresponding to the current value;
a second switch operable to control operation of the voltage-to-current converter circuit, on the basis of the high-potential-side sense enable signal; and
a fourth switch operable to control operation of the voltage-to-current converter circuit, on the basis of a potential of the third terminal, in parallel with the second switch.
2. The method of claim 1 , wherein
the semiconductor device further comprises
a fourth terminal to be coupled to the second node.
3. A method of monitoring battery voltage, the method using at least one battery voltage monitoring device,
wherein the device comprises:
a plurality of voltage measurement units provided for each group of a plurality of unit cells series-coupled in multi-stage for configuring an assembled battery; and
a battery system controller coupled to the voltage measurement units,
wherein each of the voltage measurement units is comprised of a semiconductor device,
wherein the semiconductor device comprises:
a first terminal to be coupled to a first node which is one electrode of a unit cell and is coupled to another unit cell in the unit cells; and
a second terminal to be coupled to a second node which is the other electrode of the unit cell and is coupled to another unit cell;
wherein the method comprises:
measuring an inter-terminal voltage between the first terminal and the second terminal by a voltage measurement circuit;
converting the inter-terminal voltage into a low-potential-side inter-terminal voltage by a first level shifter circuit;
comparing the low-potential-side inter-terminal voltage with a predetermined reference voltage by a comparator circuit;
converting a low-potential-side shunt control signal into a high-potential-side shunt control signal by a second level shifter circuit; and
short-circuiting the first terminal and the second terminal via a first resistor, on the basis of the high-potential-side shunt control signal by a first switch,
wherein the semiconductor device further comprises:
a third terminal to be coupled to the first node; and
a second resistor coupled between the first terminal and the third terminal,
wherein the method further comprises:
converting a low-potential-side sense enable signal into a high-potential-side sense enable signal by a third level shifter circuit;
converting a low-potential-side cell balance enable signal into a high-potential-side cell balance enable signal by a fourth level shifter circuit; and
short-circuiting the third terminal and the second terminal, on the basis of the high-potential-side cell balance enable signal by a third switch,
wherein the first level shifter circuit comprises:
a voltage-to-current converter circuit;
a current-to-voltage converter circuit;
a second switch; and
a fourth switch, and
wherein the method further comprises:
converting the inter-terminal voltage into a current value corresponding to the inter-terminal voltage by the voltage-to-current converter circuit;
converting the current value into a low-potential-side inter-terminal voltage corresponding to the current value by the current-to-voltage converter circuit;
controlling operation of the voltage-to-current converter circuit, on the basis of the high-potential-side sense enable signal by the second switch; and
controlling operation of the voltage-to-current converter circuit by the fourth switch, on the basis of a potential of the third terminal, in parallel with the second switch.
4. The method of claim 3 , wherein
the semiconductor device further comprises
a fourth terminal to be coupled to the second node.