Shunt resistor based current sensor
View Patent ↗A temperature sensor ( 60 ) is placed positionally corresponding to a central portion of a shunt resistor portion (SR). According to the configuration, it is possible to detect an approximately average temperature of the shunt resistor portion (SR) while avoiding a temperature biased in the temperature distribution in the shunt resistor portion (SR). As a result, the temperature of the shunt resistor portion which is the base of the resistance is reliably detected to enable the accuracy of current detection to be improved.
1. A shunt resistor based current sensor comprising:
a busbar that includes a shunt resistor portion, and that has a substantially planar plate shape;
a circuit board that is disposed on the busbar;
a pair of connection terminal portions that are disposed corresponding to both end portions of the shunt resistor portion, and that are electrically connected to the circuit board;
a voltage detecting unit that is disposed on the circuit board, and that detects a value of a voltage which is applied to the circuit board through the pair of connection terminal portions, in order to detect a magnitude of a current to be measured flowing through the busbar; and
a temperature detecting unit that is disposed on the circuit board, and that detects a temperature of a vicinity of the busbar in order to allow the voltage detecting unit to perform correction,
wherein the temperature detecting unit is placed positionally corresponding to a central portion of the shunt resistor portion in the busbar; and
wherein, interposed between the busbar and the circuit board is a connecting portion that thermally couples the busbar to the temperature detecting unit.
2. The shunt resistor based current sensor according to claim 1 , further comprising:
a heat conduction member that is interposed between the busbar and the circuit board.
3. The shunt resistor based current sensor according to claim 1 , wherein the circuit board includes a pattern which is located between the connecting portion and the temperature detecting unit.
4. The shunt resistor based current sensor according to claim 1 , wherein the busbar is formed into a substantially L-like shape with a through hole being formed in at least one of end portions of the busbar.
5. The shunt resistor based current sensor according to claim 1 , wherein the pair of connection terminal portions are configured into a cantilever-like shape.
6. The shunt resistor based current sensor according to claim 1 , wherein the pair of connection terminal portions are formed by a same material of the busbar and are elongated from the busbar.
7. The shunt resistor based current sensor according to claim 1 , wherein the temperature detecting unit is disposed on a surface that is opposite to a surface on which the voltage detecting unit is mounted.
8. The shunt resistor based current sensor according to claim 1 , wherein the circuit board is supported by interposing the connecting portion in a region opposite to the connection terminal portions.
9. The shunt resistor based current sensor according to claim 1 , wherein the connecting portion is part of the busbar deformed toward the circuit board.
10. The shunt resistor based current sensor according to claim 1 , wherein the connecting portion is connected to the circuit board.
11. The shunt resistor based current sensor according to claim 1 , wherein the connecting portion is placed in a position corresponding to the central portion of the shunt resistor portion in the busbar.