Estimation apparatus, current sensor, system, and estimation method

Abstract

SOLUTION: An estimation apparatus comprises an acquisition unit which acquires at least one of: at least one of a current value of a current output from at least one magnetoelectric conversion element and a voltage value of a voltage applied to the at least one magnetoelectric conversion element; and at least one of a current value of a current and a voltage value of a voltage input to a signal processing IC, in a current sensor. The estimation apparatus also comprises an estimation unit which estimates a temperature of a circuit board which includes the current sensor and a land portion in contact with the primary terminal of the current sensor and on which the current sensor is mounted, based on: a predetermined coefficient which is based on at least one of a heat transfer characteristic between the at least one magnetoelectric conversion element and the land portion and a heat transfer characteristic between the signal processing IC and the land portion in the circuit board; and at least one of: at least one of the current value and the voltage value of the at least one magnetoelectric conversion element; and at least one of the current value and the voltage value of the signal processing IC.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an estimation device, a current sensor, a system, and an estimation method. [Background technology]

[0002] Patent Document 1 describes detecting the temperature of a Hall element to detect overheating of the Hall element. Patent Document 2 describes limiting the supply of power current to a radio frequency power amplifier by a current limiting transistor when an abnormality in the power current is detected even when no abnormal temperature is detected. Patent Document 3 describes determining poor heat dissipation of a semiconductor switch based on the temperature difference between the internal temperature estimated based on the current supplied to the semiconductor switch and the actual temperature. [Prior art document] [Patent documents] [Patent Document 1] Patent No. 6546884 [Patent Document 2] Japanese Patent Application Laid-Open No. 9-019048 [Patent Document 3] JP 2023-009339 A Summary of the Invention [Problem to be solved by the invention]

[0003] If the current measured by the current sensor is large, the allowable temperature of the board on which the current sensor is mounted may reach its limit before the allowable temperature of the elements inside the current sensor, which may cause a malfunction of the board. [Means for solving the problem]

[0004] An estimation device according to one embodiment of the present invention may include an acquisition unit that acquires at least one of the current value of the current output from the at least one magneto-electric conversion element and the voltage value of the voltage applied to the at least one magneto-electric conversion element, and at least one of the current value of the current and the voltage value of the voltage input to the signal processing IC, in a current sensor having at least one magneto-electric conversion element, a primary conductor through which a measurement current measured by the at least one magneto-electric conversion element flows and a primary terminal electrically connected to the primary conductor, a signal processing IC that processes a signal output from the at least one magneto-electric conversion element, and a sealing portion that seals the at least one magneto-electric conversion element, the primary conductor, and the signal processing IC. The estimation device may have the current sensor and a land portion in contact with the primary terminal of the current sensor, and may include an estimation unit that estimates the temperature of the substrate based on a predetermined coefficient based on at least one of the heat transfer characteristics between the at least one magneto-electric conversion element and the land portion and the heat transfer characteristics between the signal processing IC and the land portion on the substrate on which the current sensor is mounted, and at least one of the current value and voltage value of the at least one magneto-electric conversion element and the current value and voltage value of the signal processing IC.

[0005] In the estimation device, the estimation unit may estimate the temperature of the substrate based on at least one of the current value and the voltage value of the at least one magnetoelectric conversion element and at least one of the current value and the voltage value of the signal processing IC.

[0006] Any of the estimation devices may further include a determination unit that determines that an abnormality has occurred in the temperature of the substrate when the temperature of the substrate does not satisfy a predetermined temperature condition.

[0007] In any of the estimation devices, the acquisition unit may further acquire a current value of a current flowing in the primary conductor, and the determination unit may determine that an overcurrent is flowing in the primary conductor when the current value of the primary conductor exceeds a predetermined threshold.

[0008] In any of the estimation devices, the estimation section may estimate the temperature of the substrate to be the temperature of the land portion of the substrate.

[0009] In any of the estimation devices, the estimation unit may estimate the temperature of the substrate based on a predetermined coefficient based on the heat transfer characteristics between the at least one magnetoelectric conversion element and the land portion and the heat transfer characteristics between the signal processing IC and the land portion, at least one of the current value and the voltage value of the at least one magnetoelectric conversion element, and at least one of the current value and the voltage value of the signal processing IC.

[0010] In any of the estimation devices, the estimation unit may estimate the temperature inside the sealing portion based on at least one of the current value and the voltage value of the at least one magnetoelectric conversion element and the current value and the voltage value of the signal processing IC, and predetermined heat transfer characteristics of the sealing portion, and may estimate the temperature of the substrate based on the temperature inside the sealing portion and the predetermined coefficient.

[0011] In any of the estimation devices, if the estimated temperature change rate of the substrate over time is higher than a predetermined change rate, the judgment unit may judge that an abnormality has occurred in at least one of the magnetoelectric conversion elements or the signal processing IC, rather than in the temperature of the substrate, even if the estimated temperature of the substrate does not satisfy the predetermined temperature condition.

[0012] A system according to one aspect of the present invention may include the estimation device, the at least one magnetoelectric conversion element, a current sensor having the primary conductor and the primary terminal, the signal processing IC, and the sealing portion, and the substrate on which the current sensor is mounted.

[0013] In the system, the current sensor may be surface mounted on the substrate.

[0014] In the system, the substrate may be an FR4 substrate.

[0015] A current sensor according to one aspect of the present invention may include any of the estimation devices, the at least one magnetoelectric conversion element, the primary conductor and the primary terminal, the signal processing IC, and the sealing portion.

[0016] In the current sensor, the signal processing IC may include the estimator.

[0017] A system according to one aspect of the present invention may include the current sensor, the substrate, and a load that operates when the measurement current is supplied.

[0018] In the system, when the temperature of the substrate estimated by the estimation unit exceeds a first threshold, the estimation device may output a first signal indicating that the temperature of the substrate has exceeded the first threshold to a control unit that controls the load. The first signal may include at least one of an instruction to output an alert signal indicating that the temperature of the substrate has exceeded the first threshold, an instruction to reduce power consumption by the load, an instruction to stop operation of the load, and an instruction to cool the substrate.

[0019] In the system, the estimation device may further include an output unit that, when the temperature of the substrate estimated by the estimation unit exceeds a first threshold, outputs a first signal indicating that the temperature of the substrate has exceeded the first threshold to a control unit that controls the load, and, when the temperature of the substrate estimated by the estimation unit exceeds a second threshold that is higher than the first threshold, outputs a second signal indicating that the temperature of the substrate has exceeded the second threshold to the control unit.

[0020] In any of the systems, the first signal may include an instruction to reduce power consumption by the load, and the second signal may include an instruction to stop operation of the load.

[0021] In any of the systems, the load may include an inverter that supplies power to a motor.

[0022] In any of the systems, the substrate may include a plurality of conductor layers, and the measurement current may flow through the plurality of conductor layers to the primary terminal and the primary conductor.

[0023] In any of the systems, the current sensor may be a surface-mount semiconductor package, and the substrate may have a primary terminal-side land portion that is a conductor portion in contact with the primary terminal of the substrate, and at least one of a plurality of through holes and a plurality of vias around the primary terminal-side land portion that electrically connect the primary terminal-side land portion and the plurality of conductor layers.

[0024] In any of the systems, at least one of the plurality of through holes and the plurality of vias may be arranged more densely in the area surrounding the land portion on the primary terminal side than in the area surrounding the land portion on the secondary terminal side.

[0025] An estimation method according to one embodiment of the present invention may include a step of acquiring at least one of the current value of the current output from the at least one magneto-electric conversion element and the voltage value of the voltage applied to the at least one magneto-electric conversion element, and at least one of the current value of the current and the voltage value of the voltage input to the signal processing IC in a current sensor having at least one magneto-electric conversion element, a primary conductor through which a measurement current measured by the at least one magneto-electric conversion element flows and a primary terminal electrically connected to the primary conductor, a signal processing IC that processes a signal output from the at least one magneto-electric conversion element, and a sealing portion that seals the at least one magneto-electric conversion element, the primary conductor, and the signal processing IC. The estimation method may include a step of estimating the temperature of a substrate having the current sensor and a land portion in contact with the primary terminal of the current sensor, and on which the current sensor is mounted, based on a predetermined coefficient based on at least one of the heat transfer characteristics between the at least one magneto-electric conversion element and the land portion and the heat transfer characteristics between the signal processing IC and the land portion, and at least one of the current value and the voltage value of the at least one magneto-electric conversion element and the current value and the voltage value of the signal processing IC.

[0026] The above summary of the invention does not list all of the features of the present invention, and subcombinations of these features may also be inventions. [Brief explanation of the drawings]

[0027] [Figure 1A] 1 is a schematic plan view of the current sensor as seen from the ceiling surface side (Z-axis direction), showing the current sensor mounted on a substrate. FIG. [Figure 1B] 1B is a cross-sectional view taken along the line AA of the substrate on which the current sensor shown in FIG. 1A is mounted. [Figure 2] FIG. 2 is a plan view schematically showing the internal configuration of the current sensor. [Figure 3] FIG. 1 is a diagram illustrating an example of functional blocks of a system including an estimation device that estimates the temperature of a substrate. [Figure 4A] 10 is a diagram showing an example of relationship information indicating the relationship between the resistance value of a magnetoelectric conversion element and the temperature of the magnetoelectric conversion element; FIG. [Figure 4B] 10 is a diagram showing an example of relationship information indicating the relationship between the diode forward voltage (Si bandgap voltage) in the signal processing IC and the temperature of the signal processing IC. FIG. [Figure 5] 10 is a flowchart illustrating an example of a procedure in which the estimation device determines whether the temperature of the substrate is abnormal. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0029] Fig. 1A is a schematic plan view of the current sensor 10 as viewed from the ceiling surface side (Z-axis direction) showing a state in which the current sensor 10 is mounted on a substrate 200. Fig. 1B is a cross-sectional view taken along line AA of the substrate 200 on which the current sensor 10 shown in Fig. 1A is mounted.

[0030] In FIG. 1A, the coordinates are defined as the X-axis direction, which is parallel to the paper surface and runs from bottom to top; the Y-axis direction, which is parallel to the paper surface and runs from left to right; and the Z-axis direction, which is perpendicular to the paper surface and runs from back to front. Any one of the X-axis, Y-axis, and Z-axis is orthogonal to the other axes. The Y-axis direction is an example of a first direction. The X-axis direction is an example of a second direction. The Z-axis direction is an example of a thickness direction.

[0031] The current sensor 10 has a primary terminal 140a through which a current to be measured flows, and a secondary terminal 150a that is used to input power to the current sensor 10 and to output a processed signal.

[0032] The substrate 200 includes a conductor layer 202 electrically connected to the primary terminal 140a via a land portion 201, and a conductor layer 204 electrically connected to the secondary terminal 150a via a land portion 203. The primary terminal 140a is soldered to the conductor layer 202 via the land portion 201. The secondary terminal 150a is soldered to the conductor layer 204 via the land portion 203. Even when the primary terminal 140a and the land portion 201 are connected via solder, the primary terminal 140a and the land portion 201 may be considered to be in contact with each other. An electric circuit 400 such as an inverter is connected to the conductor layer 202, and current from an electric device is supplied to the primary terminal 140a via the conductor layer 202. Examples of the conductor layer 202 and the conductor layer 204 include substrates on which wiring is formed. The electric circuit 400 is an example of a load. The electric circuit 400 may be electrically connected to the conductor layer 202 via a conductor such as a cable. The electric circuit 400 may include an inverter circuit, and a connector and a terminal block for connecting the inverter circuit to an externally installed motor or power supply equipment.

[0033] 1B, the conductor layer 202 and the conductor layer 204 are configured with a plurality of layers, and the plurality of conductor layers 202 are electrically connected via a through-hole array 206 in which a plurality of through-holes are arranged in an array. The plurality of conductor layers 202 may be electrically connected via a plurality of vias. The plurality of conductor layers 204 may be electrically connected via a plurality of vias.

[0034] In the conductor layer 204 on the secondary terminal side, multiple through holes 208 connect the wiring or circuits between the multilayer boards for the general purpose of connecting the wiring or circuits between the multilayer boards. Similar through holes are provided in the conductor layer 202 on the primary terminal side. However, in the area directly below or near the lands, which are the solder connections between the primary terminals and the board, it is preferable to arrange a large number of through holes or vias in a concentrated manner, such as through hole array 206. That is, the multiple through holes constituting the through hole array 206 may be densely arranged in the area near the connection between the land portion 201 and the primary terminal 140a. The area where multiple through holes are densely arranged has a larger number of through holes per unit area than other areas. Distributing heat generated within the current sensor 10 to the multiple conductor layers 202 via the multiple through holes or vias arranged directly below or near the lands improves the heat dissipation performance of the current generated within the current sensor 10. Furthermore, the current flowing through the conductor layers of the board is quickly distributed throughout the multiple layers, thereby minimizing the temperature rise of the board caused by the current.

[0035] The plurality of conductor layers 202 and the plurality of conductor layers 204 may each be a metal layer, for example, a copper foil layer. For example, the diameter of each through hole included in the through-hole array 206 may be 1.6 mm or less. The spacing between each through hole included in the through-hole array 206 may be 2 mm or less. The substrate 200 may have 20 or more through holes as the through-hole array 206 directly below the primary terminal 140a and within 10 mm of the primary terminal 140a. The interior of each through-hole in the through-hole array 206 may be filled with solder.

[0036] In the current sensor 10 configured as described above, if the measurement current flowing through the primary terminal 140a via the electrical circuit 400 is large, the internal temperature of the current sensor 10 rises via the primary terminal 140a. Therefore, it is conceivable to detect the internal temperature of the current sensor 10 and notify the external device. However, if the measurement current is large, the allowable temperature of the substrate 200 on which the current sensor 10 is mounted may reach its limit before the allowable temperature of the internal elements of the current sensor 10, potentially causing a malfunction in the substrate 200. For example, the allowable temperature of a typical IC manufactured using a Si wafer is approximately 150°C, the allowable temperature of a typical magnetoelectric transducer manufactured using a GaAs wafer is approximately 165°C, and the allowable temperature of a typical FR4 substrate manufactured using glass epoxy is approximately 130°C. Therefore, the temperature of the FR4 substrate may reach its allowable temperature before the temperature of the IC or magnetoelectric transducer reaches its allowable temperature.

[0037] When the substrate 200 is an FR4 substrate and the current sensor 10 is surface-mounted on the substrate 200, the temperature of the substrate is likely to reach the allowable temperature before the temperature of the IC or the magnetoelectric conversion element reaches the allowable temperature. In this case, the substrate 200 may be a multi-layer FR4 substrate having a copper foil thickness of 70 μm or less and including multiple conductor layers.

[0038] On the other hand, when a temperature sensor is provided on the substrate 200 to measure the temperature of the substrate 200, it is necessary to secure space for the temperature sensor on the substrate 200. However, it may be difficult to secure extra space on the substrate 200. Furthermore, adding a temperature sensor increases the number of components, thereby decreasing reliability and increasing costs.

[0039] Therefore, in this embodiment, the temperature of the substrate 200 is estimated and an abnormality caused by a temperature rise of the substrate 200 is detected without adding a separate temperature sensor.

[0040] 2 is a plan view schematically showing the internal configuration of the current sensor 10. The current sensor 10 includes a signal processing IC 100, a magnetoelectric conversion element 20, a magnetoelectric conversion element 22, a sealing portion 130, a lead frame 140, and a lead frame 150. The magnetoelectric conversion element 20 and the magnetoelectric conversion element 22 are electrically connected to the signal processing IC 100 via a wire 30. The signal processing IC 100 is electrically connected to the lead frame 150 via a wire 108. The wire 30 is an example of a first wire, and the wire 108 is an example of a second wire. The current sensor 10 is an example of a surface-mount semiconductor package.

[0041] The lead frame 140 includes a pair of primary terminals 140a protruding from the side surface 130a of the sealing portion 130, and a primary conductor 140b sealed in the sealing portion 130 and arranged so as to surround at least a portion of the magnetoelectric conversion element 20 and the magnetoelectric conversion element 22. The lead frame 150 includes a plurality of secondary terminals 150a protruding from the side surface 130b opposite the side surface 130a of the sealing portion 130 in the Y-axis direction, and a secondary conductor 150b electrically connected to the signal processing IC 100 via the wire 108.

[0042] The lead frame 140 has a U-shaped portion in a plan view so that a measurement current input from one of the pair of primary terminals 140a is output from the other of the pair of primary terminals 140a. The magnetoelectric conversion element 20 is disposed inside the U-shaped portion. The magnetoelectric conversion element 22 is disposed outside the U-shaped portion. The shapes of the lead frame 140 and the lead frame 150 shown in FIG. 1A are merely examples, and the shapes of the lead frame 140 and the lead frame 150 may be any shape.

[0043] Lead frame 140 is physically separated from and electrically insulated from lead frame 150. Lead frame 140 and lead frame 150 are electrically insulated with a withstand voltage of 480 V or more. Primary terminal 140 a is electrically connected to a high-voltage power supply system. Secondary terminal 150 a is electrically connected to a low-voltage power supply system that applies a voltage lower than that of the high-voltage power supply system.

[0044] The sealing section 130 seals the magnetoelectric transducer 20, the magnetoelectric transducer 22, the primary conductor 140b, the secondary conductor 150b, the signal processing IC 100, the wire 30, and the wire 108 with a molding resin. The sealing section 130 may be formed by compression molding or transfer molding using a mold. The molding resin may be, for example, an epoxy-based thermosetting resin with silica added. The molding resin may be a thermoplastic resin such as a liquid crystal polymer.

[0045] The magnetoelectric conversion elements 20 and 22 detect a magnetic field in a specific direction that changes in response to the measurement current flowing through the primary conductor 140b, and the signal processing IC 100 inputs a signal proportional to the magnitude of the magnetic field, calculates the difference between the magnetoelectric conversion elements 20 and 22 to cancel external magnetic noise, amplifies the signal with a desired gain, and outputs it via the lead frame 150. The magnetoelectric conversion elements 20 and 22 are an example of an element that outputs a signal in response to the current flowing through the lead frame 140. The magnetoelectric conversion elements 20 and 22 are made of a compound semiconductor formed on a GaAs substrate, and are chips cut into a square or rectangular shape when viewed from above in the Z-axis direction.

[0046] When detecting a magnetic field in the Z-axis direction, the magnetoelectric conversion elements 20 and 22 may be Hall elements. When detecting a magnetic field in one axis direction on the XY plane, the magnetoelectric conversion elements 20 and 22 may be magnetoresistive elements such as AMR sensors, TMR sensors, or GMR sensors, or fluxgate elements. When the magnetoelectric conversion elements 20 and 22 are magnetoresistive elements, the magnetoelectric conversion element 20 may be disposed at a position facing a portion of the U-shaped portion of the lead frame 140 to which one lead terminal is connected, and the magnetoelectric conversion element 22 may be disposed at a position facing a portion of the U-shaped portion of the lead frame 140 to which the other lead terminal is connected.

[0047] The signal processing IC 100 is a large-scale integrated circuit (LSI). The signal processing IC 100 is a signal processing circuit and a bias circuit made of a Si monolithic semiconductor formed on a Si substrate. The bias circuit applies a corrected drive current or drive voltage to the magnetoelectric conversion elements 20 and 22. The signal processing circuit processes an output signal corresponding to the magnitude of the magnetic field output from the magnetoelectric conversion elements 20 and 22. The signal processing circuit corrects the measurement current flowing through the lead frame 140 based on the output signal and outputs an output signal indicating an accurate current value via the secondary terminal 150a. The signal processing circuit reduces noise components contained in the output signals of the magnetoelectric conversion elements 20 and 22 based on the difference between the output signals of the magnetoelectric conversion elements 20 and 22, amplifies the output signals of the magnetoelectric conversion elements 20 and 22 with the noise components reduced, calculates the current value of the measurement current based on the amplified output signal, and outputs an output signal indicating the current value.

[0048] In this embodiment, an example will be described in which the current sensor 10 includes two magnetoelectric conversion elements, but the current sensor 10 may include at least one magnetoelectric conversion element. Also, in this embodiment, an example will be described in which the magnetoelectric conversion elements 20 and 22 are chips independent of the signal processing IC 100. However, the magnetoelectric conversion elements 20 and 22 may be silicon monolithic magnetoelectric conversion elements built into the signal processing IC 100.

[0049] FIG. 3 is a functional block diagram of an example of a system including an estimation device 300 that estimates the temperature of the substrate 200.

[0050] The estimation device 300 includes a control unit 310 and a storage unit 320. The control unit 310 may be configured with a microprocessor such as a CPU or an MPU, or a microcontroller such as an MCU. The signal processing IC 100 may function as the estimation device 300. The storage unit 320 stores information necessary for the estimation device 300 to estimate the temperature of the substrate 200 on which the current sensor 10 is mounted. The estimation device 300 may be provided in a device separate from the current sensor 10 that can communicate with the current sensor 10. The estimation device 300 is communicatively connected to an electric circuit 400 that receives or outputs a measurement current measured by the current sensor 10. The electric circuit 400 includes a control unit 402 that includes a processor or the like that controls the operation of the electric circuit 400.

[0051] The control unit 310 has an acquisition unit 312, an estimation unit 314, a determination unit 316, and an output unit 318. The acquisition unit 312 acquires the current value Ia of the current flowing through the primary conductor 140b. The acquisition unit 312 may acquire the current value derived by the above-mentioned signal processing circuit as the current value I flowing through the primary conductor 140b.

[0052] The acquiring unit 312 acquires the current value Ib of the current output from the magnetoelectric conversion element 20 and the magnetoelectric conversion element 22 and the voltage value Vb of the voltage applied to the magnetoelectric conversion element 20 and the magnetoelectric conversion element 22. The acquiring unit 312 may acquire the current value Ib of the current output from the magnetoelectric conversion element 20 and the magnetoelectric conversion element 22 and the voltage value Vb of the voltage applied to the magnetoelectric conversion element 20 and the magnetoelectric conversion element 22 from control information of the signal processing IC 100 that controls the power supplied to the magnetoelectric conversion element 20 and the magnetoelectric conversion element 22.

[0053] The acquisition unit 312 acquires the current value Ic of the current and the voltage value Vc of the voltage input to the signal processing IC 100. The acquisition unit 312 may acquire the current value Ic and the voltage value Vc from a reference voltage source built into the signal processing IC 100.

[0054] The estimation unit 314 may estimate the temperature of the substrate 200 based on a predetermined coefficient based on at least one of the heat transfer characteristics between each of the magnetoelectric conversion elements 20 and 22 and the primary conductor 140b and the heat transfer characteristics between the signal processing IC 100 and the primary conductor 140b, and on at least one of the current value Ib and voltage value Vb of each of the magnetoelectric conversion elements 20 and 22 and the current value Ic and voltage value Vc of the signal processing IC 100. The predetermined coefficient based on at least one of the heat transfer characteristics between each of the magnetoelectric conversion elements 20 and 22 and the primary conductor 140b and the heat transfer characteristics between the signal processing IC 100 and the primary conductor 140b may be determined based on a relationship ΔT1 between the temperatures of the magnetoelectric conversion elements 20 and 22 and the signal processing IC 100 and the temperature of the primary terminal 140a, which will be described later.

[0055] The estimation unit 314 may estimate the temperature of the substrate 200 based on a predetermined coefficient based on at least one of the heat transfer characteristics between each of the magnetoelectric conversion elements 20 and 22 and the land portion 201 and the heat transfer characteristics between the signal processing IC 100 and the land portion 201, and on at least one of the current value Ib and voltage value Vb of each of the magnetoelectric conversion elements 20 and 22 and the current value Ic and voltage value Vc of the signal processing IC 100. The predetermined coefficient based on at least one of the heat transfer characteristics between each of the magnetoelectric conversion elements 20 and 22 and the land portion 201 and the heat transfer characteristics between the signal processing IC 100 and the land portion 201 may be determined based on a relationship ΔT1 between the temperatures of the magnetoelectric conversion elements 20 and 22 and the signal processing IC 100 and the temperature of the primary terminal 140a, and a relationship ΔT2 between the temperature of the primary conductor 140b and the temperature of the land portion 201 connected to the primary terminal 140a, which will be described later.

[0056] The estimation unit 314 may estimate the temperature of the land portion 201 in contact with the primary terminal 140a of the substrate 200 as the temperature of the substrate 200. The estimation unit 314 may regard the temperature of the land portion 201 in contact with the primary terminal 140a via solder as the temperature of the land portion 201 in contact with the primary terminal 140a of the substrate 200 and estimate it as the temperature of the substrate 200.

[0057] The heat transfer characteristics between each of the magnetoelectric conversion elements 20 and 22 and the primary conductor 140b are predetermined based on at least one of the distance between each of the magnetoelectric conversion elements 20 and 22 and the primary conductor 140b and the thermal conductivity of the material constituting the sealing portion 130, i.e., the molding resin.

[0058] The heat transfer characteristics between the signal processing IC 100 and the primary conductor 140b are predetermined based on at least one of the distance between the signal processing IC 100 and the primary conductor 140b and the thermal conductivity of the material that makes up the sealing portion 130.

[0059] Here, the relationship ΔT1 between the temperatures of the magnetoelectric conversion elements 20 and 22 and the signal processing IC 100 and the temperature of the primary terminal 140a depends on the heat transfer function of the molding resin present between the magnetoelectric conversion elements 20 and 22 and the signal processing IC 100 and the primary conductor 140a. The relationship ΔT1 also depends on the relative positions of the magnetoelectric conversion elements 20 and 22 and the signal processing IC 100 sealed in the sealing portion 130 and the primary conductor 140b, as well as the material and shape of the primary conductor 140b. Furthermore, when a heat dissipation member such as a heat dissipation fin is attached to the current sensor 10, the relationship ΔT1 between the temperatures of the magnetoelectric conversion elements 20 and 22 and the signal processing IC 100 and the temperature of the primary terminal 140a also depends on the heat transfer function of the heat dissipation member.

[0060] The relationship ΔT2 between the temperature of primary conductor 140b and the temperature of land portion 201 connected to primary terminal 140a depends on the material and shape of primary terminal 140a and the type of solder that makes up land portion 201, i.e., the thermal conductivity of the solder and the thickness of the solder layer. ΔT2 also depends on the distance from land portion 201 to the load circuit or current draw cable on board 200, and on the thermal conductivity, which is determined by the width or thickness or number of layers of copper foil that forms the current wiring route on board 200. When forced cooling is performed from outside current sensor 10 and board 200, ΔT2 also depends on the cooling effect.

[0061] The relationship ΔT3 between the temperature of the land portion 201 and the temperature of any other location on the substrate 200 depends on the thermal conductivity of the substrate 200, which depends on the width, thickness, and number of copper foil layers of the substrate 200, the distance to the circuit configured on the substrate 200, the distance to the current draw cable, etc.

[0062] Therefore, the heat transfer characteristics between each of the magnetoelectric conversion elements 20 and 22 and any location on the substrate 200 depend on the relationships ΔT1, Δ2, and ΔT3. Taking these into consideration, coefficients for deriving the temperature of the substrate 200 from the temperatures of the magnetoelectric conversion elements 20 and 22 and coefficients for deriving the temperature of the substrate 200 from the temperature of the signal processing IC 100 may be determined in advance based on experimental results, etc.

[0063] For example, when the estimation unit 314 estimates the temperature of the land portion 201 of the substrate 200 as the temperature of the substrate 200, the above heat transfer characteristics are estimated based on the relationship ΔT1 and the relationship ΔT2, and when the estimation unit 314 estimates the temperature of any other location on the substrate 200, or the average temperature of the substrate, etc. as the temperature of the substrate 200, the above heat transfer characteristics are estimated based on the relationship ΔT1, the relationship ΔT2, and the relationship ΔT3.

[0064] The estimation unit 314 of the current sensor 10 may derive resistance values ​​Rb of the magnetoelectric conversion elements 20 and 22 from the current values ​​Ib and voltage values ​​Vb of the magnetoelectric conversion elements 20 and 22, respectively, and estimate the temperatures of the magnetoelectric conversion elements 20 and 22 based on the derived resistance value Rb and relationship information indicating the relationship between the resistance values ​​of the magnetoelectric conversion elements 20 and 22 and the temperatures of the magnetoelectric conversion elements 20 and 22. Furthermore, the estimation unit 314 may multiply the estimated temperatures T1 and T2 of the magnetoelectric conversion elements 20 and 22, respectively, by a predetermined coefficient, and estimate the temperature of the substrate 200 based on the obtained temperatures. The estimation unit 314 may estimate the temperature of the substrate 200 as the average value of two temperatures derived by multiplying the estimated temperatures of the magnetoelectric conversion elements 20 and 22 by the predetermined coefficient, or the higher temperature.

[0065] 4A is an example of relationship information showing the relationship between the resistance values ​​of the magnetoelectric conversion elements 20 and 22 and the temperatures of the magnetoelectric conversion elements 20 and 22. The estimation unit 314 may acquire the temperatures T1 and T2 of the magnetoelectric conversion elements 20 and 22 based on the resistance values ​​Rb of the magnetoelectric conversion elements 20 and 22 and the relationship information as shown in FIG. 4A. The acquisition unit 312 may derive the resistance values ​​R1 and R2 of the magnetoelectric conversion elements 20 and 22 based on the voltage value Vb of the voltage applied to the magnetoelectric conversion elements 20 and 22 and the current value Ib of the current output from the secondary terminals 150a of the magnetoelectric conversion elements 20 and 22.

[0066] 4B is an example of relationship information indicating the relationship between the forward voltage of the Si diode and the temperature of the signal processing IC 100. The estimation unit 314 may estimate the temperature of the signal processing IC 100 based on the relationship information indicating the relationship between the voltage value of the reference voltage source of the signal processing IC 100, i.e., the bandgap voltage value (forward voltage of the Si diode), and the temperature of the signal processing IC 100, and on the voltage value Vc acquired from the reference voltage source. Furthermore, the estimation unit 314 may estimate the temperature of the substrate 200 by multiplying the estimated temperature of the signal processing IC 100 by a predetermined coefficient.

[0067] The estimation unit 314 may estimate the temperature of the substrate 200 based on the temperature of the substrate 200 estimated from the resistance values ​​of the magnetoelectric conversion elements 20 and 22 and the temperature of the substrate 200 estimated from the bandgap voltage of the signal processing IC 100. The estimation unit 314 may estimate, as the temperature of the substrate 200, the average value or the maximum value of the temperature of the substrate 200 estimated from the resistance values ​​of the magnetoelectric conversion elements 20 and 22 and the temperature of the substrate 200 estimated from the bandgap voltage of the signal processing IC 100.

[0068] Among the components mounted on the substrate 200, the part in contact with the primary terminal 140a tends to generate the most heat inside the current sensor 10, and therefore the land part 201 in contact with the primary terminal 140a can be said to be the part on the substrate with the highest temperature. In other words, when the estimation unit 314 estimates the maximum value of the temperature of the substrate 200 as the estimated value of the temperature of the substrate 200, it may be assumed, for example, that the maximum value of the temperature of the substrate 200 is the temperature of the land part 201.

[0069] The determination unit 316 determines that an abnormality in the temperature of the substrate 200 has occurred when the temperature of the substrate 200 does not satisfy a predetermined temperature condition. When the temperature of the substrate 200 exceeds a first threshold TH1, the determination unit 316 may determine that an increase in the temperature of the substrate 200 should be suppressed. When the temperature of the substrate 200 exceeds the first threshold TH1, the determination unit 316 may determine that an alert signal indicating that the temperature of the substrate 200 has exceeded the first threshold TH1 should be output, may determine that the power consumed by the electric circuit 400 should be suppressed, may determine that the electric circuit 400 should operate in a power saving mode, or may determine that the substrate 200 should be cooled. When the temperature of the substrate 200 exceeds a second threshold TH2 that is higher than the first threshold TH1, the determination unit 316 may determine that the operation of the electric circuit 400 should be stopped.

[0070] If the electric circuit 400 has an inverter circuit that supplies power to the motor, the determination unit 316 may determine that the inverter circuit should be operated to operate the motor in a power saving mode when the temperature of the substrate 200 exceeds a first threshold value TH1. The determination unit 316 may determine that the motor should be stopped when the temperature of the substrate 200 exceeds a second threshold value TH2.

[0071] The determining unit 316 may determine that an overcurrent is flowing through the primary conductor 140b when the current value Ia of the current flowing through the primary conductor 140b exceeds a predetermined threshold value THa.

[0072] When the temperature of the substrate 200 exceeds the first threshold value TH1 as a result of the determination by the determination unit 316, the output unit 318 may output a signal indicating that the temperature of the substrate 200 has exceeded the first threshold value TH1 to the control unit 402 that controls the electric circuit 400. When the temperature of the substrate 200 exceeds the second threshold value TH2, the output unit 318 may output a signal indicating that the temperature of the substrate 200 has exceeded the second threshold value TH2 to the control unit 402.

[0073] When the temperature of the substrate 200 exceeds a first threshold value TH1 as a result of the determination by the determination unit 316, the output unit 318 may output a signal including an instruction to reduce the power consumed by the electric circuit 400 to the control unit 402. When the temperature of the substrate 200 exceeds a second threshold value TH2, the output unit 318 may output a signal including an instruction to stop the operation of the electric circuit 400 to the control unit 402.

[0074] If the temperature of the substrate 200 exceeds the first threshold value TH1 as a result of the judgment by the judgment unit 316, the output unit 318 may output to the control unit 402 at least one of a signal including an instruction to reduce the power consumed by the electrical circuit 400, an alert signal indicating that the temperature of the substrate 200 has exceeded the first threshold value TH1, and a signal including an instruction to cool the substrate 200.

[0075] Examples of means for cooling the substrate 200 include increasing the rotation speed of a cooling fan installed near the substrate 200, circulating a cooling liquid flowing through the pipes of a water-cooled heat sink installed near the substrate 200 while cooling it, or increasing the circulation speed of the cooling liquid, increasing the current to a Peltier element installed near the substrate 200, increasing the amount of air blown by a compressor installed near the substrate 200, or decreasing the temperature of the air blown.

[0076] When the current value Ia of the current flowing through the primary conductor 140b exceeds a predetermined threshold value THa, the output unit 318 may output a signal indicating that an overcurrent is flowing through the primary conductor 140b to the control unit 402.

[0077] Here, an abnormality in the magnetoelectric conversion element 20 or 22, or the signal processing IC 100 may cause a sudden change in the temperature of the magnetoelectric conversion element 20 or 22, or the signal processing IC 100. In this case, there is a possibility that the temperature of the magnetoelectric conversion element 20 or 22, or the signal processing IC 100 may reach the allowable temperature before the heat reaches the substrate 200. In such a case, the determination unit 316 determines that the accuracy of the temperature of the substrate 200 estimated from the temperature of the magnetoelectric conversion element 20 or 22, or the signal processing IC 100 is low, and it is preferable not to determine that there is an abnormality in the temperature of the substrate 200. In such a case, it is preferable that the determination unit 316 determines that there is an abnormality in the magnetoelectric conversion element 20 or 22, or the signal processing IC 100. Therefore, the judgment unit 316 may judge that an abnormality has occurred in the magnetoelectric conversion element 20 or the magnetoelectric conversion element 22, or the signal processing IC 100, if the estimated temperature change rate of the substrate 200 is higher than a predetermined change rate, and in particular, even if the estimated substrate temperature does not satisfy the predetermined temperature conditions, it may judge that an abnormality has occurred in the magnetoelectric conversion element 20 or the magnetoelectric conversion element 22, or the signal processing IC 100, rather than an abnormality in the temperature of the substrate 200.

[0078] If the estimated temperature of the magnetoelectric conversion element 20 or the magnetoelectric conversion element 22, or the signal processing IC 100 is higher than a predetermined temperature, the judgment unit 316 may judge that an abnormality has occurred in the magnetoelectric conversion element 20 or the magnetoelectric conversion element 22, or the signal processing IC 100, and in particular, even if the estimated temperature of the substrate 200 does not satisfy the predetermined temperature condition, it may judge that an abnormality has occurred in the magnetoelectric conversion element 20 or the magnetoelectric conversion element 22, or the signal processing IC 100, rather than an abnormality in the temperature of the substrate 200.

[0079] Even when the output unit 318 receives a signal from the determination unit 316 indicating that an overcurrent is flowing in the primary conductor 140b, it may stop the current flowing from the electric circuit 400 to the primary conductor 140b of the current sensor 10 and notify the occurrence of an overcurrent. The estimation device 300 may notify an alarm message on a display or the like according to the type of signal. The control device may register the content of the signal, i.e., the content of the alarm indicating that an abnormality in the temperature of the substrate 200, an abnormality in the magnetoelectric conversion element 20 or the magnetoelectric conversion element 22, an abnormality in the signal processing IC 100, or an inflow of an overcurrent into the current sensor 10 has occurred, as a log in memory.

[0080] FIG. 5 is a flowchart showing an example of a procedure in which the estimation device 300 determines whether the temperature of the substrate 200 is abnormal.

[0081] The acquiring unit 312 acquires the current value Ia of the current flowing through the primary conductor 140b (S100). The acquiring unit 312 may acquire, as the current value Ia flowing through the primary conductor 140b, a current value derived by a signal processing circuit included in the signal processing IC 100. The determining unit 316 determines whether the current value Ia is equal to or greater than a threshold value THa (S102).

[0082] If the current value Ia is equal to or greater than the threshold value THa, the output unit 318 outputs an alarm signal indicating an overcurrent abnormality, in which an overcurrent is flowing through the current sensor 10 (S104). On the other hand, if the current value Ia is smaller than the threshold value THa, the acquisition unit 312 acquires the current value Ib of the current output from the magnetoelectric conversion elements 20 and 22, the voltage value Vb of the voltage applied to the magnetoelectric conversion elements 20 and 22, and the current value Ic of the current and the voltage value Vc of the voltage input to the signal processing IC 100 (S106). The acquisition unit 312 may acquire the current value Ib of the current output from the magnetoelectric conversion elements 20 and 22 and the voltage value Vb of the voltage applied to the magnetoelectric conversion elements 20 and 22 from control information of the signal processing IC 100, which controls the power supplied to the magnetoelectric conversion elements 20 and 22. The acquisition section 312 may acquire the current value Ic and the voltage value Vc from a reference voltage source built into the signal processing IC 100.

[0083] The estimation unit 314 estimates the temperatures Tb of the magnetoelectric conversion elements 20 and 22 and the temperature Tc of the signal processing IC 100 based on at least one of the current value Ib and the voltage value Vb of the magnetoelectric conversion elements 20 and 22 and at least one of the current value Ic and the voltage value Vc of the signal processing IC (S108). The estimation unit 314 may derive the resistance values ​​Rb of the magnetoelectric conversion elements 20 and 22 from the current values ​​Ib and voltage values ​​Vb of the magnetoelectric conversion elements 20 and 22, and estimate the temperatures Tb of the magnetoelectric conversion elements 20 and 22 based on the derived resistance value Rb and relationship information indicating the relationship between the resistance values ​​of the magnetoelectric conversion elements 20 and 22 and the temperatures of the magnetoelectric conversion elements 20 and 22. The estimation unit 314 may estimate the temperature Tc of the signal processing IC 100 based on relationship information indicating the relationship between the voltage value of the reference voltage source of the signal processing IC 100 and the temperature of the signal processing IC 100, and the voltage value Vc acquired from the reference voltage source.

[0084] The estimation unit 314 estimates the temperature Td of the substrate 200 from the temperatures Tb of the magnetoelectric conversion elements 20 and 22 and the temperature Tc of the signal processing IC 100 (S110). The estimation unit 314 may estimate, as the temperature Td of the substrate 200, the average value or the maximum value of the temperatures of the substrate 200 estimated from the temperatures Tb of the magnetoelectric conversion elements 20 and 22 and the temperature of the substrate 200 estimated from the temperature Tc of the signal processing IC 100.

[0085] The determination unit 316 determines whether the temperature Td of the substrate 200 is equal to or higher than the second threshold value TH2 (S112). If the temperature Td of the substrate 200 is equal to or higher than the second threshold value TH2, the output unit 318 outputs an alarm signal indicating a command to stop the operation of the electric circuit 400 (S114).

[0086] If the temperature Td of the substrate 200 is lower than the second threshold TH2, the determination unit 316 determines whether the temperature Td of the substrate 200 is equal to or higher than the first threshold TH1 (S116). If the temperature Td of the substrate 200 is equal to or higher than the first threshold TH1, the output unit 318 outputs an alarm signal indicating that the electric circuit 400 should be operated in a power saving mode (S118).

[0087] If the temperature Td of the substrate 200 is lower than the first threshold value TH1, the judgment unit 316 judges that no abnormality has occurred in the temperature of the current sensor 10 or the temperature of the substrate 200, and the output unit 318 does not output an alarm signal, causing the electrical circuit 400 to continue normal processing (S120).

[0088] As described above, according to the estimation device 300 of this embodiment, even if the measured current measured by the current sensor 10 is large, the allowable temperature of the substrate 200 on which the current sensor 10 is mounted reaches its limit before the allowable temperature of the elements inside the current sensor 10, thereby preventing malfunctions from occurring in the substrate 200.

[0089] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0090] It should be noted that the execution order of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0091] 10 Current Sensor 20, 22 Magnetoelectric conversion element 30,108 wires 130 Sealing part 140 lead frame 140a primary terminal 140b Primary conductor 150 lead frames 150a secondary terminal 150b secondary conductor 200 boards 201 Land Club 202,204 Conductor layer 203 Land Department 206 through-hole array 208 through hole 300 Estimation device 310 Control Unit 312 Acquisition Department 314 Estimation Department 316 Judgment section 318 Output Section 320 Storage section 400 Electrical Circuits 402 Control Unit 100 Signal Processing IC

Claims

1. a signal processing IC that processes a signal output from the at least one magnetoelectric conversion element; and a sealing portion that seals the at least one magnetoelectric conversion element, the primary conductor, and the signal processing IC. The current sensor has at least one magnetoelectric conversion element, a primary conductor through which a measurement current measured by the at least one magnetoelectric conversion element flows, and a primary terminal electrically connected to the primary conductor. The current sensor has an acquisition unit that acquires at least one of a current value of a current output from the at least one magnetoelectric conversion element and a voltage value of a voltage applied to the at least one magnetoelectric conversion element, and at least one of a current value of a current and a voltage value of a voltage input to the signal processing IC. an estimation unit that includes the current sensor and a land portion in contact with the primary terminal of the current sensor, and that estimates a temperature of the substrate on which the current sensor is mounted, based on a predetermined coefficient based on at least one of a heat transfer characteristic between the at least one magnetoelectric conversion element and the land portion and a heat transfer characteristic between the signal processing IC and the land portion, and at least one of the current value and the voltage value of the at least one magnetoelectric conversion element and the current value and the voltage value of the signal processing IC; An estimation device comprising:

2. 2. The estimation device according to claim 1, wherein the estimation unit estimates the temperature of the substrate based on at least one of the current value and the voltage value of the at least one magnetoelectric conversion element and at least one of the current value and the voltage value of the signal processing IC.

3. The estimation device according to claim 1 , further comprising a determination unit that determines that an abnormality has occurred in the temperature of the substrate when the temperature of the substrate does not satisfy a predetermined temperature condition.

4. The acquisition unit further acquires a current value of a current flowing through the primary conductor, The estimation device according to claim 3 , wherein the determination unit determines that an overcurrent is flowing in the primary conductor when the current value in the primary conductor exceeds a predetermined threshold value.

5. The estimation device according to claim 1 , wherein the estimation unit estimates a temperature at the land portion of the substrate as the temperature of the substrate.

6. 2. The estimation device according to claim 1, wherein the estimation unit estimates the temperature of the substrate based on a predetermined coefficient based on heat transfer characteristics between the at least one magnetoelectric conversion element and the primary conductor and heat transfer characteristics between the signal processing IC and the primary conductor, at least one of the current value and the voltage value of the at least one magnetoelectric conversion element, and at least one of the current value and the voltage value of the signal processing IC.

7. 2. The estimation device according to claim 1, wherein the estimation unit estimates the temperature inside the sealing portion based on at least one of the current value and the voltage value of the at least one magnetoelectric conversion element and the current value and the voltage value of the signal processing IC, and predetermined heat transfer characteristics of the sealing portion, and estimates the temperature of the substrate based on the temperature inside the sealing portion and the predetermined coefficient.

8. 4. The estimation device according to claim 3, wherein the determination unit determines that an abnormality has occurred in the at least one magnetoelectric conversion element or the signal processing IC, rather than in the temperature of the substrate, when the estimated rate of change of temperature of the substrate with respect to time is higher than a predetermined rate of change, even if the estimated temperature of the substrate does not satisfy the predetermined temperature condition.

9. An estimation device according to any one of claims 1 to 8, a current sensor including the at least one magnetoelectric transducer, the primary conductor and the primary terminal, the signal processing IC, and the sealing portion; A system comprising the substrate on which the current sensor is mounted.

10. The system of claim 9 , wherein the current sensor is surface mounted to the substrate.

11. The system of claim 9 , wherein the substrate is an FR4 substrate.

12. An estimation device according to any one of claims 1 to 8; the at least one magnetoelectric conversion element; the primary conductor and the primary terminal; the signal processing IC; The sealing portion A current sensor comprising:

13. The current sensor of claim 12 , wherein the signal processing IC comprises the estimator.

14. A current sensor according to claim 12; the substrate; a load that operates when the measurement current is supplied; A system comprising:

15. The estimation device includes: When the temperature of the substrate estimated by the estimation unit exceeds a first threshold, a first signal indicating that the temperature of the substrate has exceeded the first threshold is output to a control unit that controls the load; 15. The system of claim 14, wherein the first signal includes at least one of an instruction to output an alert signal indicating that the temperature of the substrate has exceeded the first threshold, an instruction to reduce power consumption by the load, an instruction to stop operation of the load, and an instruction to cool the substrate.

16. The estimation device includes:

15. The system of claim 14, further comprising an output unit that outputs a first signal to a control unit that controls the load, when the temperature of the substrate estimated by the estimator exceeds a first threshold, indicating that the temperature of the substrate has exceeded the first threshold, and that outputs a second signal to the control unit, when the temperature of the substrate estimated by the estimator exceeds a second threshold that is higher than the first threshold, indicating that the temperature of the substrate has exceeded the second threshold.

17. the first signal includes an instruction to reduce power consumed by the load; 17. The system of claim 16, wherein the second signal includes an instruction to stop operation of the load.

18. The system of claim 16 , wherein the load includes an inverter that powers a motor.

19. the substrate includes a plurality of conductor layers; The system of claim 14 , wherein the measurement current flows through the plurality of conductor layers to the primary terminal and the primary conductor.

20. the current sensor is a surface-mount semiconductor package, The substrate is a land portion on the primary terminal side, which is a conductor portion that contacts the primary terminal of the substrate; At least one of a plurality of through holes and a plurality of vias are provided around the land portion on the primary terminal side to electrically connect the land portion on the primary terminal side and the plurality of conductor layers.

20. The system of claim 19, comprising:

21. 21. The system of claim 20, wherein the at least one of the plurality of through holes and the plurality of vias is more densely arranged in the area surrounding the land portion on the primary terminal side than in the area surrounding the land portion on the secondary terminal side.

22. a signal processing IC that processes a signal output from the at least one magnetoelectric conversion element; and a sealing portion that seals the at least one magnetoelectric conversion element, the primary conductor, and the signal processing IC. In the current sensor, the current sensor has at least one magnetoelectric conversion element, a primary conductor through which a measurement current measured by the at least one magnetoelectric conversion element flows and a primary terminal electrically connected to the primary conductor; a step of estimating a temperature of a substrate having the current sensor and a land portion in contact with the primary terminal of the current sensor, the substrate having the current sensor mounted thereon, based on a predetermined coefficient based on at least one of a heat transfer characteristic between the at least one magnetoelectric conversion element and the land portion and a heat transfer characteristic between the signal processing IC and the land portion, and at least one of the current value and the voltage value of the at least one magnetoelectric conversion element and the current value and the voltage value of the signal processing IC; An estimation method comprising:

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