Adjustment circuit, current detection device, and method for manufacturing current detection device

Abstract

The present invention provides a technology capable of performing output adjustment with high accuracy in current detection. An adjustment circuit according to the present disclosure comprises: a first amplifier; and a first resistor circuit connected to an inverting input and an output of the first amplifier. The first resistor circuit has a plurality of first pads on which a resistor or a jumper can be mounted. On each of the plurality of first pads, either the resistor or the jumper is mounted, or none of the resistor or the jumper is mounted. The first resistor circuit has a first combined resistance value corresponding to the combination thereof, and adjusts and outputs the gain of the input voltage by using the first combined resistance value.

Description

Regulating circuit, current detection device, and method of manufacturing current detection device

[0001] The present disclosure relates to a regulation circuit, a current detection device, and a method for manufacturing a current detection device.

[0002] A method using a shunt resistor is known as a method for detecting current. Specifically, a shunt resistor is connected in series to a flow path through which a current to be measured flows, and the voltage generated across the shunt resistor is detected to calculate the current value. A current detection device using this type of method includes a shunt resistor and a current detection circuit, which includes, for example, an amplifier, an A / D converter, a microcontroller, etc. The voltage detected from the shunt resistor is amplified by the amplifier circuit. The amplified voltage is further adjusted for gain and offset by an adjustment circuit. For example, Patent Document 1 discloses technology related to the adjustment circuit.

[0003] JP 2012-85407 A

[0004] In the current detection devices described above, output errors occur for each current detection device due to variations in the resistance value of the shunt resistor, and therefore, in order to improve accuracy, it is necessary to adjust the volume for each device.

[0005] FIG. 1 is a diagram illustrating the problems inherent in conventional current detection devices. As shown in FIG. 1, the relationship between input voltage (Vin) and output voltage (Vout) is ideally proportional, as indicated by a straight line passing through the origin. However, the relationship between input voltage and output voltage before adjustment deviates from the ideal value due to error. Furthermore, the degree of deviation varies depending on the current detection device manufactured. Possible methods for adjusting this output error include adjustment using a variable resistor, an electronic volume, or a thick-film resistor for functional trimming. However, these components have poor temperature characteristics (large temperature coefficient of resistance, TCR), and self-heating increases output error, making them unsuitable for use in current detection devices that require high-precision detection of large currents. In particular, the use of thin-film resistors for functional trimming improves temperature characteristics, but the resistor element is exposed due to laser trimming, which means no protective coating. This increases the risk of problems caused by electrolytic corrosion, which is characteristic of thin-film resistors, and requires high moisture-proofing measures, such as coatings.

[0006] One possible method is to implement multiple resistors with different resistance values ​​and switch between them using a relay to adjust the required resistance value. However, to finely adjust the resistance value, it is necessary to implement many resistors and relays, which makes the circuit large-scale. In addition, the temperature characteristics and weather resistance of the relay may be affected, which may affect the quality or lifespan.

[0007] Another possible method for adjusting output error is to replace the mounted thin-film resistor after measuring the characteristics. However, this requires manual work using a soldering iron, making the process complicated. Furthermore, if this process is adopted, heat is applied three times: first by reflow soldering the thin-film resistor, then by soldering the thin-film resistor, and then by soldering the thin-film resistor again. This applies thermal stress to the board and other components, potentially affecting their quality or lifespan. Furthermore, because this is manual work and requires a long lead time, there are concerns about increased costs.

[0008] Therefore, the present disclosure provides a technique that enables highly accurate output adjustment in current detection.

[0009] In order to solve the above problem, the adjustment circuit of the present disclosure comprises a first amplifier and a first resistance circuit connected to the inverting input and output of the first amplifier, the first resistance circuit having a plurality of first pads on which resistors or jumpers can be mounted, each of the plurality of first pads having either the resistor or the jumper mounted thereon, or neither mounted thereon, the first resistance circuit having a first combined resistance value according to the combination thereof, and adjusting and outputting the gain of the input voltage using the first combined resistance value.

[0010] The current detection device disclosed herein comprises a shunt resistor having a voltage detection terminal, an amplifier circuit connected to the voltage detection terminal and amplifying the voltage detected from the voltage detection terminal, and a first adjustment circuit connected to the output of the amplifier circuit and adjusting the gain of the voltage amplified by the amplifier circuit, wherein the first adjustment circuit has a first amplifier and a first resistance circuit connected to the inverting input and output of the first amplifier, the first resistance circuit has a plurality of first pads on which resistors or jumpers can be mounted, and each of the plurality of first pads has either the resistor or the jumper mounted thereon, or neither mounted thereon, and the first resistance circuit has a first combined resistance value corresponding to the combination of these, and adjusts the gain of the input voltage using the first combined resistance value and outputs it.

[0011] A manufacturing method of a current detection device according to the present disclosure is a manufacturing method of a current detection device including a shunt resistor and a detection circuit board, the manufacturing method including: performing primary mounting by mounting predetermined components on the detection circuit board to configure an amplifier circuit that amplifies a voltage detected from the shunt resistor and a first adjustment circuit that adjusts the gain of the voltage amplified by the amplifier circuit, the first adjustment circuit having a first amplifier and a first resistance circuit that is connected to an inverting input and an output of the first amplifier and has a plurality of secondary mounting pads; performing a current test of the detection circuit board after the primary mounting; deriving an optimal first combined resistance value of the first resistor circuit based on the results of an electrical test; calculating a combination to select either mounting a secondary adjustment resistor, mounting a jumper, or not mounting on each of the plurality of secondary mounting pads based on the first combined resistance value, and selecting a resistance value of the secondary adjustment resistor; performing secondary mounting to mount the secondary adjustment resistor or the jumper on the plurality of secondary mounting pads; and connecting a detection circuit board after the secondary mounting process to a voltage detection terminal provided on the shunt resistor, thereby completing the current detection device.

[0012] Further features related to the present disclosure will become apparent from the description of this specification and the accompanying drawings. Also, aspects of the present disclosure are achieved and realized by the elements and combinations of various elements and the aspects of the following detailed description and the appended claims. The description of this specification is merely exemplary and does not limit the scope or application of the claims of the present disclosure in any way.

[0013] According to the technology of the present disclosure, highly accurate output adjustment is possible in current detection. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiment.

[0014] 1 is a diagram for explaining the prior art; FIG. 2 is a perspective view of a shunt resistor included in the current detection device according to the first embodiment; FIG. 3 is a perspective view of the current detection device according to the first embodiment; FIG. 4 is a circuit diagram of the current detection device having an adjustment circuit according to the first embodiment; FIG. 5 is a flowchart showing a method for manufacturing the current detection device according to the first embodiment; FIG. 6 is a circuit diagram of the current detection device having an adjustment circuit according to the second embodiment; and FIG. 7 is a circuit diagram of the current detection device having an adjustment circuit according to the third embodiment.

[0015] 2 is a perspective view of a shunt resistor 10 included in a current detection device according to Embodiment 1. The shunt resistor 10 includes a resistive element 11, electrodes 12 and 13, voltage detection terminals 14 and 15, and busbar mounting holes 16 and 17.

[0016] The resistor 11 is formed in the shape of a rectangular plate having a predetermined thickness and width. Examples of materials for the resistor 11 include alloys such as copper-nickel alloys, copper-manganese alloys, iron-chromium alloys, and nickel-chromium alloys. The pair of electrodes 12 and 13 are connected to both sides of the resistor 11 by, for example, welding. Examples of welding methods include electron beam welding, laser beam welding, and brazing. The electrodes 12 and 13 are plate-shaped and made of a highly conductive metal such as copper. The voltage detection terminal 14 is provided near the resistor 11 so as to protrude from the top surface of the electrode 12. The voltage detection terminal 15 is provided near the resistor 11 so as to protrude from the top surface of the electrode 13. The busbar mounting hole 16 is provided in the electrode 12. The busbar mounting hole 17 is provided in the electrode 13.

[0017] 3 is a perspective view of the current detection device 100 according to the first embodiment. The current detection device 100 includes a shunt resistor 10 and a detection circuit board 20. The detection circuit board 20 is disposed on top of the shunt resistor 10, and the voltage detection terminals 14 and 15 are inserted into through holes formed in the detection circuit board 20, and the shunt resistor 10 and the detection circuit board 20 are electrically connected by soldering or the like. The detection circuit board 20 includes an amplifier circuit 23, an A / D converter 24, a microcontroller 25, a connector 26, and an adjustment circuit 30.

[0018] The potentials of the electrodes 12 and 13 at the positions of the voltage detection terminals 14 and 15 of the shunt resistor 10 are input to the amplifier circuit 23. The amplifier circuit 23 has an amplifier, amplifies the difference (voltage) between the input potentials, and outputs it as a voltage signal. The output voltage signal is input to the adjustment circuit 30. The adjustment circuit 30 adjusts the gain of the input voltage and outputs the adjusted voltage signal to the A / D converter 24. The A / D converter 24 A / D converts the input voltage signal and outputs a digital signal. The output digital signal is input to the microcontroller 25. The microcontroller 25 processes the digital signal to calculate a voltage value, and calculates a current value (measured current value) based on the voltage value and the resistance value of the shunt resistor 10.

[0019] The shunt resistor 10 used in the current detection device 100 has a temperature coefficient of resistance (TCR) close to 0, which enables highly accurate current detection over the entire temperature range of the usage environment.

[0020] <Configuration Example of Adjustment Circuit> Fig. 4 is a circuit diagram of a current detection device 100 including an adjustment circuit 30 according to the first embodiment. Fig. 4 shows only the shunt resistor 10, the amplifier circuit 23, and the adjustment circuit 30. The amplifier circuit 23 includes resistors R1 and R2, a resistor C1, and an isolation amplifier 231.

[0021] The adjustment circuit 30 includes two resistors R3, a resistor R5, a resistor circuit 301, and an amplifier 302. The resistor circuit 301 is located in a feedback circuit connecting the inverting input and output of the amplifier 302. The resistor circuit 301 is provided with pads R41 to R44 (hereinafter sometimes referred to as "secondary mounting pads"), two in series and two in parallel, on which resistors can be mounted. While FIG. 4 shows four pads, the number can be any number greater than two (multiple). The resistor circuit 301 also has terminals T1 and T2 that can be connected to the outside.

[0022] Resistors (hereinafter sometimes referred to as "secondary adjustment resistors") or jumpers are mounted on each of the pads R41 to R44 as needed. The resistance value (first combined resistance value) of the resistance circuit 301 is adjusted by combining the resistors or jumpers (short) mounted on the pads R41 to R44 and the pads (open) on which no resistors are mounted. This combined resistance value adjusts the gain of the voltage output from the amplifier circuit 23. Because the resistance circuit 301 always requires a resistance value, at least one of the two pads arranged in series has a resistor mounted on it, and the other has a resistor or jumper mounted on it, or is unmounted (open). In some cases, resistors are mounted on all of the pads R41 to R44.

[0023] For example, a chip resistor, which is a general surface-mount fixed resistor, can be used as the resistor. Thin film chip resistors in particular have excellent temperature characteristics. The temperature coefficient of resistance is ±100×10 －６ It is preferable to use a chip resistor in the range of ±10 × 10 －６ / K resistors have a smaller temperature coefficient of resistance (TCR), so there is less change in resistance value with temperature. Furthermore, chip resistors generally have a lower risk of electrolytic corrosion than thin-film resistors for function trimming, since the resistive element is protected by a protective coating. Thus, by using thin-film chip resistors as resistors and combining them with jumpers and opens to form the resistance circuit 301, a high-quality current detection device with high current detection accuracy can be realized.

[0024] <Method of Manufacturing Current Detector> FIG. 5 is a flowchart showing a method of manufacturing the current detector 100 according to the first embodiment. As described below, this manufacturing method uses a computer (not shown) configured to calculate an optimal resistance value (combined resistance value) of the resistor circuit 301 of the adjustment circuit 30. Information necessary for current measurement, such as information (resistance value) of the shunt resistor 10, is stored in advance in a storage device of the computer. The computer is also configured to control a resistance value switching system (not shown) connected to terminals T1 and T2 of the resistor circuit 301. The resistance value switching system includes multiple fixed resistors and multiple relays, and a variable resistance circuit whose resistance value can be changed by switching the relays is constructed. A software program for implementing the above-described functions is pre-installed in the computer.

[0025] Step S1: Primary Mounting The manufacturer mounts components other than the secondary adjustment resistors and jumpers on the detection circuit board 20. In the primary mounting, for example, surface-mounted components are mounted by reflow soldering.

[0026] Step S2: Electrical Test (Calculation of Resistance Value and Selection of Resistor) The manufacturer performs an electrical test on the detection circuit board 20. In the electrical test, the manufacturer connects the above-mentioned resistance value switching system to terminals T1 and T2 of the resistance circuit 301. The manufacturer also connects a measurement fixture (jig) to the detection circuit board 20.

[0027] In step S21, the computer adjusts the energization of the measurement fixture according to a program based on information (such as the resistance value) of the shunt resistor 10. The computer then calculates the optimum resistance value of the resistor circuit 301 according to the desired gain. Here, by using the actual measured value as the information (such as the resistance value) of the shunt resistor 10, the optimum resistance value of the resistor circuit 301 can be accurately calculated. Instead of the actual measured value, the resistance value of the shunt resistor 10 for each production lot may be used.

[0028] In step S22, the computer selects a secondary adjustment resistor by deriving a combination of the secondary adjustment resistor, jumper, and open based on the calculated resistance value of the resistance circuit 301. In selecting the secondary adjustment resistor, the resistance value of each secondary adjustment resistor is derived from a plurality of thin film chip resistors having different inherent resistance values ​​so that the combined resistance value of the resistance circuit 301 becomes the calculated optimum resistance value.

[0029] Here, the resistance tolerance of the thin-film chip resistor can be, for example, ±0.5%. Furthermore, thin-film chip resistors having resistance values ​​in the E12 series are prepared as the selected resistors, and a resistor can be selected from the E12 series. This allows the resistance value of the resistance circuit 301 to be adjusted in increments of 0.5 Ω or less. Furthermore, since fewer resistor varieties are prepared as secondary adjustment resistors, manufacturers no longer need to maintain large inventories. On the other hand, if the resistance circuit 301 is to be realized with a single resistor, for example, the thin-film chip resistor that can be prepared is the E192 series. In this case, adjustment in increments of 0.5 Ω or less is not possible, and more varieties than the E12 series are required.

[0030] Step S3: Secondary Mounting The manufacturer mounts the selected secondary adjustment resistor and jumper on the secondary mounting pads (pads R41 to R44). That is, up to four chip resistors selected as combinations that will produce the same or similar resistance value as the resistance value calculated in step S21 are mounted on the secondary mounting pads. By configuring the secondary mounting pads as a circuit that combines series and parallel connections, it is possible to accommodate a variety of resistance values ​​depending on the mounting method, in addition to the resistance value of the chip resistor. The mounting method involves applying solder with a dispenser, mounting the secondary adjustment resistor, and then performing laser soldering or iron soldering.

[0031] Step S4: Assembling the Current Detector The manufacturer assembles the detection circuit board 20 on which the secondary adjustment resistor is mounted in step S3, and the shunt resistor 10. In this way, the current detector 100 is completed.

[0032] As described above, by performing the entire process from the electrical test, calculation of the optimal resistance value of the resistor circuit 301, selection of the optimal secondary adjustment resistor, and secondary mounting in one facility, lead time can be shortened. This process reduces the number of times heat is applied to only two times: the primary mounting and the secondary mounting. In other words, by selecting the optimal resistor before mounting the resistor, the process of replacing the resistor after measuring the completed mounting board is eliminated. This improves quality by reducing the thermal history when removing the resistor, and improves efficiency by consolidating the processes.

[0033] Summary of First Embodiment As described above, the adjustment circuit 30 according to the first embodiment includes an amplifier 302 (first amplifier) ​​and a resistance circuit 301 (first resistance circuit) connected to the inverting input and output of the amplifier 302. The resistance circuit 301 has pads R41 to R44 (plurality of first pads) on which resistors or jumpers can be mounted. Each of the pads R41 to R44 has either a resistor or a jumper mounted thereon, or neither mounted thereon, and the resistance circuit 301 has a combined resistance value (first combined resistance value) corresponding to the combination of these. The adjustment circuit 30 adjusts the gain of the input voltage according to the combined resistance value of the resistance circuit 301 and outputs the result.

[0034] As described above, in the adjustment circuit 30 of this embodiment, the combined resistance value of the resistance circuit 301 is determined by a combination of resistors, jumpers, or non-mounted components. Such an adjustment circuit 30 enables highly accurate output adjustment. The current detection device 100 equipped with the adjustment circuit 30 is of high quality and can achieve highly accurate current detection.

[0035] Second Embodiment <Configuration Example of Adjustment Circuit> Figure 6 is a circuit diagram of a current detection device 200 including an adjustment circuit 40 according to a second embodiment. As shown in Figure 6, the adjustment circuit 40 (first adjustment circuit) according to the second embodiment differs from the first embodiment in that the resistance circuit 301 includes a resistor R45 (sometimes referred to as a "primary adjustment resistor") that is mounted in the primary mounting (step S1). The resistor R45 is connected in series to the pads R41 to R44. A thin-film chip resistor with excellent temperature characteristics can also be used as the resistor R45.

[0036] <Method of Manufacturing Current Detection Device> In the second embodiment, in the electrical test (step S2), the resistance value of the resistance circuit 301 is adjusted by adding the resistance value of the resistor R45. The other points are the same as those in the first embodiment.

[0037] [Third Embodiment] <Configuration Example of Adjustment Circuit> Fig. 7 is a circuit diagram of a current detection device 300 having adjustment circuits 40 and 50 according to a third embodiment. As shown in Fig. 7, the current detection device 300 according to the third embodiment further includes an adjustment circuit 50 that adjusts the offset of the voltage output from the amplifier circuit 23. In other words, the current detection device 300 can adjust the gain and offset of the voltage output from the amplifier circuit 23. The other configurations are the same as those of the second embodiment.

[0038] The offset-adjusting adjustment circuit 50, like the gain-adjusting adjustment circuits 30 and 40, includes a resistance circuit 501, an amplifier 502, and a resistor R7. The resistance circuit 501 is connected to the non-inverting input of the amplifier 502. The output of the amplifier 502 is connected to the non-inverting input of the amplifier 302. The resistance circuit 501 includes a resistor R65 (primary adjustment resistor), pads R61 to R64 (secondary mounting pads), and terminals T3 and T4. Two pads R61 to R64 are connected in series and two in parallel. While FIG. 7 shows four pads, the number can be any number greater than two (multiple). The resistor R65 is connected in series with the pads R61 to R64. A thin-film chip resistor with excellent temperature characteristics can also be used for the resistor R65.

[0039] <Method of Manufacturing a Current Detector> In the primary mounting (step S1), a resistor R65 is mounted. In the electrical test (step S2), the optimal resistance value of the resistor circuit 501 is calculated by connecting terminals T3 and T4 to an external resistance value switching system. The method for adjusting the resistance value (second combined resistance value) of the resistor circuit 501 is the same as the method for adjusting the resistance value of the resistor circuit 301 of the adjustment circuit 30 ( FIG. 5 ). In the secondary mounting (step S3), selected secondary adjustment resistors or jumpers are mounted on pads R61 to R64. The resistance value of the resistor circuit 501 is adjusted by combining the mounted secondary adjustment resistors, jumpers, and opens. As with the first embodiment, thin-film chip resistors having E12 series resistance values ​​can be used for the secondary adjustment resistors mounted on pads R61 to R64 of the adjustment circuit 50.

[0040] Summary of the Third Embodiment As described above, the adjustment circuit 50 (second adjustment circuit) according to the third embodiment includes an amplifier 502 (second amplifier) ​​and a resistance circuit 501 (second resistance circuit) connected to the non-inverting input of the amplifier 502. The output of the amplifier 502 is connected to the non-inverting input of the amplifier 302. The resistance circuit 501 has pads R61 to R64 (plurality of second pads) on which resistors or jumpers can be mounted. Each of the pads R61 to R64 has either a resistor or a jumper mounted thereon, or neither is mounted thereon, and the resistance circuit 501 has a combined resistance value (second combined resistance value) corresponding to the combination of these. The adjustment circuit 50 adjusts the offset of the input voltage using the combined resistance value of the resistance circuit 501 and outputs the result.

[0041] In this way, highly accurate output adjustment can be performed by adjusting the gain of the input voltage with the adjustment circuit 30 or 40 and adjusting the offset of the input voltage with the adjustment circuit 50. Therefore, a current detection device including the adjustment circuit 30 or 40 and the adjustment circuit 50 is of high quality and can achieve high current detection accuracy.

[0042] [Modifications] The present disclosure is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present disclosure, and it is not necessary to include all of the described configurations. Furthermore, a part of one embodiment can be replaced with a configuration of another embodiment. Furthermore, a configuration of another embodiment can be added to a configuration of one embodiment. Furthermore, a part of the configuration of each embodiment can be added to, deleted from, or substituted for a part of the configuration of another embodiment.

[0043] [Contribution to the Environment] According to the present disclosure, the current detection accuracy of a current detection device is improved, and weather resistance is also improved. This allows accurate current measurement in the equipment used, and further reduces the risk of failure in harsh environments. This contributes to improving the power consumption efficiency and safety of the equipment used. Therefore, the present disclosure can contribute to the achievement of Goal 3 "Good Health and Well-Being," Goal 7 "Affordable and Clean Energy," and Goal 9 "Industry, Innovation and Infrastructure" of the United Nations-led Sustainable Development Goals (SDGs).

[0044] REFERENCE SIGNS LIST 100, 200, 300...Current detection device 10...Shunt resistor 11...Resistor 12, 13...Electrodes 14, 15...Voltage detection terminals 16, 17...Bus bar mounting holes 20...Detection circuit board 23...Amplifier circuit 24...A / D converter 25...Microcontroller 26...Connector 30, 40, 50...Adjustment circuit 301, 501...Resistor circuit 302, 502...Amplifier

Claims

1. An adjustment circuit comprising: a first amplifier; and a first resistance circuit connected to the inverting input and output of the first amplifier, wherein the first resistance circuit has a plurality of first pads on which resistors or jumpers can be mounted, each of the plurality of first pads having either a resistor or a jumper mounted thereon, or neither mounted thereon, the first resistance circuit having a first combined resistance value corresponding to the combination thereof, and which adjusts the gain of an input voltage using the first combined resistance value and outputs the adjusted gain.

2. The adjustment circuit according to claim 1, further comprising: a second amplifier; and a second resistance circuit connected to the non-inverting input of the second amplifier, wherein the output of the second amplifier is connected to the non-inverting input of the first amplifier, wherein the second resistance circuit has a plurality of second pads on which resistors or jumpers can be mounted, and each of the plurality of second pads has either a resistor or a jumper mounted thereon, or neither mounted thereon, and the second resistance circuit has a second combined resistance value corresponding to the combination thereof, and wherein the adjustment circuit adjusts the offset of the input voltage using the second combined resistance value and outputs the adjusted voltage.

3. The adjustment circuit according to claim 2, wherein each of the plurality of first pads and the plurality of second pads is connected in parallel and in series.

4. The adjustment circuit of claim 3, wherein the first resistance circuit and / or the second resistance circuit further includes a resistor connected in series with the plurality of first pads and / or the plurality of second pads, and the first combined resistance value and / or the second combined resistance value includes the resistance value of the resistor.

5. The adjustment circuit according to claim 3 or 4, wherein the resistor is a thin film chip resistor with a resistance tolerance of ±0.5% and has a resistance value in the E12 series.

6. A current detection device comprising: a shunt resistor having a voltage detection terminal; an amplifier circuit connected to the voltage detection terminal and amplifying a voltage detected from the voltage detection terminal; and a first adjustment circuit connected to the output of the amplifier circuit and adjusting the gain of the voltage amplified by the amplifier circuit, wherein the first adjustment circuit has a first amplifier and a first resistance circuit connected to the inverting input and output of the first amplifier, the first resistance circuit having a plurality of first pads on which resistors or jumpers can be mounted, each of the plurality of first pads having either a resistor or a jumper mounted thereon or neither mounted thereon, the first resistance circuit having a first combined resistance value corresponding to the combination of these, and adjusting the gain of an input voltage by the first combined resistance value before outputting it.

7. The current detection device according to claim 6, further comprising a second adjustment circuit that adjusts the offset of the voltage amplified by the amplifier circuit, the second adjustment circuit having a second amplifier and a second resistance circuit connected to the non-inverting input of the second amplifier, the output of the second amplifier being connected to the non-inverting input of the first amplifier, the second resistance circuit having a plurality of second pads on which resistors or jumpers can be mounted, each of the plurality of second pads having either the resistor or the jumper mounted thereon or neither mounted thereon, the second resistance circuit having a second combined resistance value corresponding to the combination thereof, and the offset of the input voltage is adjusted by the second combined resistance value before being output.

8. The current detection device according to claim 7, wherein each of the plurality of first pads and the plurality of second pads is connected in parallel and in series.

9. The current detection device according to claim 8, wherein the first resistance circuit and / or the second resistance circuit further includes a resistor connected in series with the plurality of first pads and / or the plurality of second pads, and the first combined resistance value and / or the second combined resistance value includes the resistance value of the resistor.

10. A current detection device according to claim 8 or 9, wherein the resistor is a thin film chip resistor with a resistance tolerance of ±0.5% and has a resistance value in the E12 series.

11. A method for manufacturing a current detection device including a shunt resistor and a detection circuit board, comprising: mounting predetermined components on the detection circuit board to form an amplifier circuit that amplifies a voltage detected from the shunt resistor and a first adjustment circuit that adjusts the gain of the voltage amplified by the amplifier circuit, the first adjustment circuit having a first amplifier and a first resistance circuit that is connected to the inverting input and output of the first amplifier and has a plurality of secondary mounting pads; performing a current test of the detection circuit board after performing the primary mounting; deriving an optimal first combined resistance value of the first resistance circuit based on the results of the current test; calculating a combination that selects whether to mount a secondary adjustment resistor, mount a jumper, or not mount it on each of the plurality of secondary mounting pads based on the first combined resistance value, and selecting a resistance value of the secondary adjustment resistor; performing a secondary mounting in which the secondary adjustment resistor or the jumper is mounted on the plurality of secondary mounting pads; connecting the detection circuit board after the secondary mounting process to a voltage detection terminal provided on the shunt resistor to complete the current detection device.

12. The method for manufacturing a current detection device according to claim 11, wherein performing the primary mounting further comprises configuring a second adjustment circuit on the detection circuit board to adjust the offset of the voltage amplified by the amplifier circuit, the second adjustment circuit having a second amplifier and a second resistance circuit connected to the non-inverting input of the second amplifier and having a plurality of secondary mounting pads, deriving an optimal second combined resistance value of the second resistance circuit based on the results of the electrical connection test, and calculating a combination of mounting a secondary adjustment resistor, mounting a jumper, or not mounting on each of the plurality of secondary mounting pads provided on the second resistance circuit based on the second combined resistance value, thereby selecting the resistance value of the secondary adjustment resistor.

13. The method for manufacturing a current detection device according to claim 12, wherein the secondary adjustment resistor is a thin film chip resistor with a resistance tolerance of ±0.5% and is selected from any resistance value in the E12 series.

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