Current sensor

Abstract

The current sensor may include a current detection unit that outputs a detection signal corresponding to the magnetic field generated in a conductor when a measurement current flows, and a signal processing unit that outputs an output signal by processing the detection signal. The signal processing unit may include a storage unit that stores a plurality of current sensitivity parameters corresponding to each of a plurality of current sensitivities that can be set for the current sensor, and a sensitivity setting unit that sets the current sensitivity of the current sensor based on one of the plurality of current sensitivity parameters stored in the storage unit.

Description

Technical Field

[0001] The present invention relates to a current sensor.

Background Art

[0002] Patent Document 1 describes that the current measurement range is expanded by using two current sensors with different magnetic sensitivities. Patent Document 2 describes that the current level of a current signal output from a Hall element is adjusted by an amplifier. Patent Document 3 describes a sensitivity switching type sensor circuit capable of significantly reducing a sudden change in a signal during amplification factor switching performed according to the magnitude of an input signal. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent No. 6190537 [Patent Document 2] US Patent Application Publication No. 2016 / 0313407 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2006-266738

Summary of the Invention

Problems to be Solved by the Invention

[0003] A current sensor capable of switching the current measurement range over a wide range is desired.

Means for Solving the Problems

[0004] A current sensor according to an aspect of the present invention may include a current detection unit that outputs a detection signal corresponding to a magnetic field generated in a conductor when a measurement current flows, and a signal processing unit that outputs an output signal by processing the detection signal. The signal processing unit may have a storage unit that stores a plurality of current sensitivity parameters corresponding to each of a plurality of current sensitivities that can be set for the current sensor. The signal processing unit may have a sensitivity setting unit that sets the current sensitivity of the current sensor based on one type of current sensitivity parameter among the plurality of current sensitivity parameters stored in the storage unit.

[0005] In the current sensor, each of the multiple current measurement ranges may be determined based on each of the multiple current sensitivities.

[0006] In any of the current sensors, the signal processing unit may receive a selection signal from outside the current sensor, select one current sensitivity parameter from the plurality of current sensitivity parameters, and set the current sensitivity of the current sensor.

[0007] In any of the current sensors, the sensitivity setting unit may have a receiving unit that receives a selection signal indicating information that identifies one type of current sensitivity parameter selected from among the plurality of current sensitivity parameters.

[0008] In any of the current sensors, the plurality of current measurement ranges include a first current measurement range that defines the minimum range of current values ​​and a second current measurement range that defines the maximum range of current values, wherein the maximum range may be three times or more the minimum range.

[0009] In any of the current sensors, the plurality of current measurement ranges may consist of five or more different current measurement ranges.

[0010] In any of the current sensors, the current detection unit may include at least one magnetoelectric conversion element.

[0011] In any of the current sensors, the at least one magnetoelectric conversion element may be a Hall element, a magnetoresistive element, or a coil.

[0012] In any of the current sensors, the sensitivity setting unit may have an amplification unit that amplifies the detection signal output from the current detection unit. The plurality of current sensitivity parameters may include at least the amplification factor of the detection signal in the amplification unit.

[0013] In any of the current sensors, the sensitivity setting unit may have a drive control unit that outputs a drive current or drive voltage to the current detection unit. The plurality of current sensitivity parameters may include at least the current value of the drive current or the voltage value of the drive voltage output from the drive control unit.

[0014] In any of the current sensors, the at least one magnetoelectric conversion element may be a Hall element. The Hall element may include a semiconductor made of group IV atoms, or a compound semiconductor made of at least two combinations of group II, III, IV, V, and VI atoms.

[0015] In any of the current sensors, the at least one magnetoelectric conversion element may be a magnetoresistive element. The magnetoresistive element may be a TMR (Total Mixed Reality) having Co, Fe, and Ni as the first component, Mg and O as the second component, and Mn as the third component, and containing at least one atom from the first component, at least one atom from the second component, and at least one atom from the third component.

[0016] In any of the current sensors, the sensitivity setting unit may include an amplification unit that amplifies the detection signal output from the current detection unit, and a drive control unit that outputs a drive current to the current detection unit. The plurality of current sensitivity parameters may include the amplification factor of the detection signal in the amplification unit, and one of either the current value of the drive current output from the drive control unit or the voltage value of the drive voltage.

[0017] In any of the current sensors, each of the multiple current measurement ranges may be determined based on each of the multiple current sensitivities. The multiple current measurement ranges may include a first current measurement range group and a second current measurement range group. The amplification ratios of each of the detection signals associated with the first current measurement range group may be different. The current values ​​of the drive currents or the voltage values ​​of the drive voltages associated with each of the second current measurement range groups may be different.

[0018] In any of the above current sensors, the current value of each drive current or the voltage value of the drive voltage associated with the first current measurement range group may be the same. The amplification factor of each detection signal associated with the second current measurement range group may be the same.

[0019] Note that the above summary of the invention does not list all the features of the present invention. Also, sub - combinations of these feature groups can also be inventions.

Brief Description of Drawings

[0020] [Figure 1] It is a diagram showing an example of a functional block of a current sensor according to this embodiment. [Figure 2] It is a diagram showing an example of a table in which the current value of the drive current and the amplification factor of the amplification unit are registered as current sensitivity parameters in association with each of a plurality of current measurement ranges. [Figure 3] It is a flowchart showing an example of a procedure for setting the current measurement range of a current sensor.

Modes for Carrying Out the Invention

[0021] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0022] Figure 1 shows an example of the functional block of the current sensor 10 according to this embodiment. The current sensor 10 measures the measurement current flowing through a conductor 20 arranged adjacent to the current sensor 10. The current sensor 10 includes a current detection unit 30 and a signal processing unit 100. The current detection unit 30 outputs a detection signal corresponding to the magnetic field generated in the conductor 20 when the measurement current flows. The current detection unit 30 includes at least one magnetoelectric conversion element. The at least one magnetoelectric conversion element may be a Hall element, a magnetoresistive element, or a coil. The Hall element may be, for example, a compound semiconductor composed of at least two types of group II, III, IV, V, and VI atoms such as InAs, GaAs, SiC, and ZnO, or a Hall element composed of silicon (Si). The magnetoresistive element may be a giant magnetoresistance (GMR) element, a semiconductor magnetoresistance (SMR) element, an anisotropic magnetoresistance (AMR) element, or a tunnel magnetoresistance (TMR) element. The tunnel magnetoresistance (TMR) element may be, for example, a TMR in which Co, Fe, and Ni are the first components, Mg and O are the second components, and Mn is the third component, and which contains at least one atom from the first component, at least one atom from the second component, and all of the atoms from the third component. The magnetoresistance element has a selection signal input terminal that receives a selection signal for current sensitivity. The current sensor 10 may also have a VDD terminal and a VSS terminal that are connected to the high voltage side and low voltage side of the drive power supply. The current sensor 10 may also have an OUT terminal that outputs a current measurement signal.

[0023] The signal processing unit 100 outputs an output signal by processing the detection signal output from the current detection unit 30. The signal processing unit 100 may be a signal processing IC composed of a large-scale integrated circuit (LSI). The signal processing IC is a signal processing circuit made of a Si monolithic semiconductor formed on a Si substrate. The signal processing circuit processes the detection signal corresponding to the magnitude of the magnetic field output from the current detection unit 30.

[0024] The signal processing unit 100 includes a sensitivity setting unit 110 and a memory unit 120. The memory unit 120 stores a plurality of current sensitivity parameters corresponding to each of the plurality of current sensitivities that can be set for the current sensor 10. The sensitivity setting unit 110 sets the current sensitivity of the current sensor 10 based on one type of current sensitivity parameter stored in the memory unit 120. The signal processing unit 100 may receive a selection signal from outside the current sensor 10, select one type of current sensitivity parameter from the plurality of current sensitivity parameters, and set the current sensitivity of the current sensor 10.

[0025] The sensitivity setting unit 110 includes a drive control unit 102, an amplification unit 104, and a reception unit 106. The drive control unit 102, the amplification unit 104, and the reception unit 106 are an example of a sensitivity setting unit that sets the current sensitivity of the current sensor 10.

[0026] The drive control unit 102 supplies a drive current or a drive voltage for driving the current detection unit 30 to the current detection unit 30. The drive control unit 102 has a constant current source or a constant voltage source and supplies a drive current or a drive voltage of a certain magnitude to the current detection unit 30. The drive control unit 102 refers to the memory unit 120 to identify the current value of the drive current or the voltage value of the drive voltage stored as one of the current sensitivity parameters to be set in the memory unit 120, and supplies a drive current or a drive voltage corresponding to the identified current value to the current detection unit 30.

[0027] The amplification unit 104 amplifies the detection signal output from the current detection unit 30 at a set amplification rate. The amplification unit 104 is an example of an amplification unit. The amplification unit 104 may include a plurality of amplification units. For example, when the amplification unit includes a first amplification unit and a second amplification unit, the amplification rate range that can be set by the first amplification unit and the amplification rate range that can be set by the second amplification unit may be different. The amplification rate range that can be set by the first amplification unit may be wider than the amplification rate range that can be set by the second amplification unit. The setting interval of the amplification rate that can be set by the first amplification unit and the setting interval of the amplification rate that can be set by the second amplification unit may be wide. Thereby, by adjusting the amplification rate of the first amplification unit, a rough amplification rate adjustment is performed, and by adjusting the amplification rate of the second amplification unit, a fine amplification rate adjustment is performed.

[0028] The sensitivity setting unit 110 sets the amplification factor set in the amplification unit 104. The sensitivity setting unit 110 refers to the memory unit 120 to identify the amplification factor of the amplification unit 104 stored in the memory unit 120 as one of the current sensitivity parameters to be set, and sets the identified amplification factor in the amplification unit 104. The sensitivity setting unit 110 also sets the current value of the drive current set in the drive control unit 102. The sensitivity setting unit 110 refers to the memory unit 120 to identify the current value of the drive current of the drive control unit 102 stored in the memory unit 120 as one of the current sensitivity parameters to be set, and sets the identified current value in the drive control unit 102.

[0029] The current sensor 10 may include an output unit that performs predetermined processing on the detection signal output from the amplification unit 104 and outputs the processed output signal. The output unit may have an AD conversion unit that converts the detection signal, which is an analog signal output from the amplification unit 104, into a digital signal. The output unit may have a ΔΣ type AD converter or an integrating type AD converter as the AD conversion unit. The output unit may have a filter that filters the detection signal, which is an analog signal output from the amplification unit 104. The output unit may have a low-pass filter that prevents aliasing errors from appearing in the detection signal converted into a digital signal by the AD conversion unit.

[0030] In the current sensor 10 configured in this way, the memory unit 120 stores multiple current sensitivity parameters for setting the current sensitivity of the current detection unit 30. The memory unit 120 may store a table as current sensitivity parameters, for example, as shown in Figure 2, in which the current value of the drive current (mA) and the amplification factor of the amplification unit 104 are registered. In addition to the current measurement range, the table may also store the magnetoelectric conversion coefficient (mT / A), which is the magnetic flux density incident on the current detection unit 30 when a measurement current flows through the conductor 20, and the magnetic sensitivity of the current detection unit 30 (mV / mT / mA). When multiple types of magnetoelectric conversion coefficients are registered in the table, the current sensor 10 may have multiple current detection units 30 that are located at different positions from the conductor 20 but have equivalent magnetic field sensitivities. Multiple magnetoelectric conversion elements with substantially the same magnetic field sensitivities are a concept that includes not only multiple magnetoelectric conversion elements with completely identical magnetic sensitivities, but also multiple magnetoelectric conversion elements that have variations in magnetic sensitivity within the range of manufacturing tolerances.

[0031] If multiple types of magnetic field sensitivities are registered in the table, the current sensor 10 may have multiple current detection units 30 with different sensitivities. The current sensitivity of the current sensor 10 is determined by the product of the magnetic sensitivity, magnetoelectric conversion coefficient, drive current, and amplification factor.

[0032] Each of the multiple current measurement ranges of the current sensor 10 configured in this way is determined based on each of the multiple current sensitivities. The multiple current measurement ranges may be determined, for example, based on upper and lower limits at which the detection signal saturates according to the multiple current sensitivities.

[0033] Multiple current measurement ranges may include a first group of current measurement ranges and a second group of current measurement ranges. The amplification factors associated with the first group of current measurement ranges may be different, and the current values ​​of the drive currents may be the same. On the other hand, the amplification factors associated with the second group of current measurement ranges may be the same, and the current values ​​of the drive currents or the voltage values ​​of the drive voltages may be different. The second group of current measurement ranges may define a range of current values ​​larger than that of the first group of current measurement ranges.

[0034] The reception unit 106 receives a selection signal indicating information that identifies the current sensitivity parameter to be set, selected from among multiple current sensitivity parameters. The reception unit 106 may function as an input / output interface for receiving signals such as selection signals from an external source, or outputting signals to an external source. The reception unit 106 may receive a selection signal indicating information that identifies the current sensitivity parameter to be set, selected by the user from among multiple current sensitivity parameters. The reception unit 106 may receive a selection signal indicating information that identifies the current measurement range to be set, selected from among multiple current measurement ranges. The multiple current measurement ranges may be defined, for example, in five or more stages.

[0035] As shown in Figure 2, the multiple current measurement ranges are defined, for example, in five stages, and include a first current measurement range that defines the minimum range of current values ​​and a second current measurement range that defines the maximum range of current values, with the maximum range of current values ​​being at least three times the minimum range of current values. Thus, with the current sensor 10 according to this embodiment, the current measurement range of the current sensor 10 is not fixed before shipment, and can be set to a more appropriate current measurement range desired by the user after shipment. This reduces the management costs or risks of inventory or procurement of the current sensor 10. In addition, since it is not necessary to set the current measurement range before shipment, the design man-hours during the manufacturing stage of the current sensor 10 can be reduced.

[0036] Figure 3 is a flowchart showing an example of the procedure for setting the current measurement range of the current sensor 10.

[0037] The reception unit 106 receives a selection signal (S100) that indicates information identifying the current sensitivity parameter to be set, selected from among multiple current sensitivity parameters. The selection signal may be included in the setting command signal output during the initial setup process or setting update process of the system equipped with the current sensor 10. The selection signal may be included in the measurement command output when the system equipped with the current sensor 10 instructs the current sensor 10 to measure the current.

[0038] The sensitivity setting unit 110 refers to the storage unit 120 and, based on the information that identifies the current sensitivity parameter to be set indicated by the selection signal, identifies the amplification factor of the amplification unit 104 and the current value of the drive current of the drive control unit 102, which are stored in the storage unit 120 as the current sensitivity parameter to be set (S102). The sensitivity setting unit 110 sets the identified amplification factor to the amplification unit 104 and sets the identified current value to the drive control unit 102 (S104).

[0039] As described above, according to this embodiment, the current measurement range of the current sensor 10 is not fixed before shipment, and can be set to a more appropriate current measurement range desired by the user after shipment. This reduces the management costs or risks of inventory or procurement of the current sensor 10. In addition, since it is not necessary to set the current measurement range before shipment, the design man-hours during the manufacturing stage of the current sensor 10 can be reduced.

[0040] 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 or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0041] It should be noted that the execution order of operations, procedures, steps, and stages in the apparatus, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before," "prior to," etc., and that these can be implemented in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," "next," etc. for convenience, it does not mean that it is essential to perform the operations in that order. [Explanation of Symbols]

[0042] 10 Current Sensor 20 Conductors 30 Current detection unit 100 Signal Processing Unit 102 Drive control unit 104 Amplifier 106 Reception Department 110 Sensitivity setting section 120 Storage section

Claims

1. A current detection unit that outputs a detection signal corresponding to the magnetic field generated in a conductor when a measured current flows, A current sensor comprising a signal processing unit that outputs an output signal by processing the aforementioned detection signal, The signal processing unit, A storage unit that stores multiple current sensitivity parameters corresponding to each of the multiple current sensitivities that can be set for the current sensor, The system includes a sensitivity setting unit that sets the current sensitivity of the current sensor based on one of the multiple current sensitivity parameters stored in the storage unit, The aforementioned sensitivity setting unit is The system further includes a receiving unit that receives a selection signal indicating information that identifies one type of current sensitivity parameter selected from the plurality of current sensitivity parameters, A current sensor that receives the selection signal from outside the current sensor via the receiving unit, selects one type of current sensitivity parameter from a plurality of current sensitivity parameters, and sets the current sensitivity of the current sensor.

2. The current sensor according to claim 1, wherein the selection signal is included in a setting command signal output during initial setup processing or setting update processing of a system equipped with the current sensor, or in a measurement command signal output when the system instructs the current sensor to measure current.

3. The current sensor according to claim 1, wherein each of the multiple current measurement ranges is determined based on each of the multiple current sensitivities.

4. The current sensor according to claim 3, wherein each of the plurality of current measurement ranges is determined based on an upper limit and a lower limit at which the detection signal saturates according to a plurality of current sensitivities.

5. The VDD terminal and VSS terminal are connected to the power supply, The OUT terminal outputs the aforementioned output signal, The current sensor according to claim 1, further comprising a selection signal input terminal for receiving the selection signal from an external source.

6. The current sensor according to claim 3, wherein the plurality of current measurement ranges include a first current measurement range that defines the minimum range of current values ​​and a second current measurement range that defines the maximum range of current values, and the maximum range is three times or more the minimum range.

7. The current sensor according to claim 6, wherein the plurality of current measurement ranges consist of five or more types of current measurement ranges.

8. The current sensor according to any one of claims 1 to 7, wherein the current detection unit includes at least one magnetoelectric conversion element.

9. The current sensor according to claim 8, wherein the at least one magnetoelectric conversion element is a Hall element, a magnetoresistive element, or a coil.

10. The sensitivity setting unit has an amplification unit that amplifies the detection signal output from the current detection unit, The current sensor according to claim 1, wherein the plurality of current sensitivity parameters include at least the amplification factor of the detection signal in the amplification unit.

11. The sensitivity setting unit has a drive control unit that outputs a drive current or drive voltage to the current detection unit. The current sensor according to claim 1, wherein the plurality of current sensitivity parameters include at least the current value of the drive current output from the drive control unit or the voltage value of the drive voltage.

12. The at least one magnetoelectric conversion element is a Hall element, The current sensor according to claim 9, wherein the Hall element includes a semiconductor composed of group IV atoms, or a compound semiconductor composed of at least two combinations of group II, group III, group IV, group V, and group VI atoms.

13. The at least one magnetoelectric conversion element is a magnetoresistive element, The current sensor according to claim 9, wherein the magnetoresistive element is a TMR comprising Co, Fe, and Ni as the first component, Mg and O as the second component, and Mn as the third component, and containing at least one atom from the first component, at least one atom from the second component, and at least one atom from the third component.

14. The aforementioned sensitivity setting unit is An amplification unit that amplifies the detection signal output from the current detection unit, A drive control unit that outputs a drive current to the current detection unit, It has, The current sensor according to claim 1, wherein the plurality of current sensitivity parameters include the amplification factor of the detection signal in the amplification unit, and one of the current value of the drive current output from the drive control unit or the voltage value of the drive voltage.

15. Based on each of the aforementioned multiple current sensitivities, each of the multiple current measurement ranges is determined. The aforementioned plurality of current measurement ranges include a first current measurement range group and a second current measurement range group, The amplification factor of each of the detection signals associated with the first current measurement range group is different. The current sensor according to claim 14, wherein the current value of the drive current or the voltage value of the drive voltage associated with each of the second current measurement range groups are different.

16. A current detection unit that outputs a detection signal corresponding to the magnetic field generated in a conductor when a measured current flows, A current sensor comprising a signal processing unit that outputs an output signal by processing the aforementioned detection signal, The signal processing unit, A storage unit that stores multiple current sensitivity parameters corresponding to each of the multiple current sensitivities that can be set for the current sensor, The system includes a sensitivity setting unit that sets the current sensitivity of the current sensor based on one of the multiple current sensitivity parameters stored in the storage unit, The aforementioned sensitivity setting unit is An amplification unit that amplifies the detection signal output from the current detection unit, A drive control unit that outputs a drive current to the current detection unit, The system includes a receiving unit that receives a selection signal indicating information that identifies one type of current sensitivity parameter selected from the plurality of current sensitivity parameters, The plurality of current sensitivity parameters include the amplification factor of the detection signal in the amplification unit, and one of the current value of the drive current output from the drive control unit or the voltage value of the drive voltage. Based on each of the aforementioned multiple current sensitivities, each of the multiple current measurement ranges is determined. The plurality of current measurement ranges include a first group of current measurement ranges and a second group of current measurement ranges that define a range of current values ​​larger than the first group of current measurement ranges. The amplification factor of each of the detection signals associated with the first current measurement range group is different. The current value of the drive current or the voltage value of the drive voltage associated with each of the second current measurement range groups is different. The sensitivity setting unit receives the selection signal from outside the current sensor via the receiving unit, selects one type of current sensitivity parameter from the plurality of current sensitivity parameters, and sets the current sensitivity of the current sensor.

17. The current value of the drive current or the voltage value of the drive voltage associated with each of the first current measurement range groups is the same. The current sensor according to claim 15 or 16, wherein the amplification factor of each of the detection signals associated with the second current measurement range group is the same.

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