Voltage divider circuit, measurement device, and substrate circuit, and method for manufacturing voltage divider circuit

Abstract

To suppress a reduction in output accuracy of a voltage divider circuit caused by the influence of wiring connected to a pair of resistors.SOLUTION: A voltage divider circuit 1 having a resistor 11 and a resistor 12 whose one ends are connected to each other, comprises first wiring connected to the other end of the resistor 11 and second wiring connected to the other end of the resistor 12. A resistance value of the resistor 11 and a resistance value of the resistor 12 are different from each other, and a resistance ratio Rr of the resistor 11 and the resistor 12 is equivalent to a resistance ratio Rl of the first wiring and the second wiring.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a voltage divider circuit, a measuring device, a substrate circuit, and a method for manufacturing a voltage divider circuit. [Background technology]

[0002] Patent Document 1 discloses a voltage divider circuit having two resistors connected in series. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-38234 Summary of the Invention [Problem to be solved by the invention]

[0004] In the voltage divider circuit described above, two resistors connected in series are connected between the wiring that supplies the input voltage and the wiring that supplies the reference voltage, and the influence of these two wirings can sometimes reduce the output accuracy of the voltage divider circuit.

[0005] For example, because the resistance temperature coefficient of the two wires is much larger than the temperature coefficient of the two resistors, the output voltage generated at the connection point of the two resistors fluctuates significantly with respect to the voltage value determined by the resistance ratio of the two resistors as the temperature of the two wires changes. Thus, there was a problem in that the influence of the two wires reduced the output accuracy of the voltage divider circuit.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to suppress a decrease in the output accuracy of a voltage divider circuit due to the influence of wiring connected to a pair of resistors. [Means for solving the problem]

[0007] According to one aspect of the present invention, a voltage divider circuit having a first resistor and a second resistor connected to each other at one end via an output wiring connected to an output section includes a first wiring connected to the other end of the first resistor and a second wiring connected to the other end of the second resistor, wherein the resistance values ​​of the first resistor and the second resistor are different from each other, and a resistance ratio between the first resistor and the second resistor is equal to a resistance ratio between the first wiring and the second wiring. [Effects of the Invention]

[0008] According to this aspect, the absolute difference between the resistance ratio of the first wiring and the second wiring and the resistance ratio of the first resistor and the second resistor becomes small, thereby suppressing fluctuations in the output voltage generated at the connection point of the first resistor and the second resistor due to temperature changes in the first wiring and the second wiring.

[0009] In this way, according to the above aspect, it is possible to suppress a decrease in the output accuracy of the voltage divider circuit due to the influence of the wiring connected to the pair of resistors. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a voltage divider circuit according to the first embodiment. [Figure 2] FIG. 2 is a diagram schematically showing a wiring pattern of the voltage divider circuit according to the first embodiment. [Figure 3] FIG. 3 is a flowchart showing an example of a method for manufacturing the voltage divider circuit according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing a modified example of the configuration of the voltage divider circuit according to the first embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of the configuration of a voltage divider circuit according to the second embodiment. [Figure 6] FIG. 6 is a diagram schematically showing a wiring pattern of a voltage divider circuit according to the second embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the configuration of a voltage divider circuit according to the third embodiment. [Figure 8]FIG. 8 is a diagram schematically showing a wiring pattern of a voltage divider circuit according to the third embodiment. [Figure 9] FIG. 9 is a diagram for explaining an implementation example of a voltage divider circuit according to the third embodiment. [Figure 10] FIG. 10 is a diagram illustrating an application example of the voltage divider circuit according to the third embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of the configuration of a voltage divider circuit according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this specification, the same or equivalent elements are designated by the same reference numerals throughout.

[0012] (First embodiment) FIG. 1 is a circuit diagram showing an example of the configuration of a voltage divider circuit 1 according to the first embodiment.

[0013] The voltage divider circuit 1 is a circuit for dividing an input voltage Vin supplied to an input terminal 1a. The voltage divider circuit 1 is employed, for example, in a measuring device that measures power, a calibration device that calibrates the measuring device, a power conversion device, and the like.

[0014] The voltage divider circuit 1 outputs the divided voltage from an output terminal 1b as an output voltage Vout. The output terminal 1b, which corresponds to the output section of the voltage divider circuit 1, is connected to, for example, the input terminal of a buffer circuit or the inverting input terminal of an amplifier. Furthermore, the input terminal 1a of the voltage divider circuit 1 is connected to, for example, a signal supply circuit that supplies an electrical signal to the voltage divider circuit 1. In the first embodiment, a buffer circuit 30 that receives an output signal from the signal supply circuit is connected to the input terminal 1a of the voltage divider circuit 1.

[0015] In the first embodiment, the voltage divider circuit 1 is formed on a substrate circuit 100 in which electronic components are arranged on a printed circuit board. The voltage divider circuit 1 includes a pair of resistors 11 and 12 connected in series, a printed wiring 21, a printed wiring 22, and an output wiring 23. Hereinafter, the pair of resistors 11 and 12 connected in series will also be simply referred to as "resistors 11 and 12."

[0016] The resistors 11 and 12 are series-connected resistors and may be referred to as a first resistor and a second resistor, respectively. Each of the resistors 11 and 12 may be, for example, a chip resistor having a resistive element and a pair of electrodes sandwiching the resistive element. Alternatively, the resistors 11 and 12 may be an array resistor in which multiple chip resistors are housed in a package.

[0017] The total resistance Rt (=R1+R2) of the resistors 11 and 12 is designed to be within the range of several mΩ to several MΩ, for example, and is 5 kΩ in the first embodiment.

[0018] In the first embodiment, the resistance value R1 of the resistor 11 and the resistance value R2 of the resistor 12 are different from each other, and FIG. 1 shows an example of a voltage divider circuit 1 in which the resistance value R1 of the resistor 11 is higher than the resistance value R2 of the resistor 12.

[0019] As a specific example, the resistance value R1 of resistor 11 is 4.95 [Ω], and the resistance value R2 of resistor 12 is 50 [mΩ]. Therefore, the voltage division ratio (R2 / Rt), which indicates the ratio of the resistance value R2 of resistor 12 to the total resistance value Rt of resistors 11 and 12, is 1 / 1000. Therefore, an output voltage Vout, which is 1 / 1000 of the voltage generated at the other end of resistor 11, is generated at a connection point N where one end of resistors 11 and 12 are connected together.

[0020] The printed wiring 21 and the printed wiring 22 correspond to the first wiring and the second wiring, respectively, and are made of a conductor layer such as aluminum foil or copper foil. In the first embodiment, the printed wirings 21 and 22 are made of copper foil.

[0021] The printed wiring 21 is a wiring for supplying an input voltage Vin, and the printed wiring 22 is a wiring for supplying a reference potential Vref. The output wiring 23 is a wiring connected to the output terminal 1b of the voltage divider circuit 1, and outputs the output voltage Vout from the output terminal 1b.

[0022] In the voltage divider circuit 1, one end of the resistor 11 and one end of the resistor 12 are connected to each other, and an output wiring 23 is connected to a connection point N between the resistors 11 and 12. In other words, the output wiring 23 is a wiring that includes the connection point N and connects the resistor 11 and the resistor 12 to each other.

[0023] In the voltage divider circuit 1, one end of the printed wiring 21 is connected to the input terminal 1a, and the other end of the printed wiring 21 is connected to the other end of the resistor 11. One end of the printed wiring 22 is connected to the other end of the resistor 12, and the other end of the printed wiring 22, which is the output terminal, is connected to the reference potential Vref.

[0024] In this configuration, resistors having a relative temperature coefficient of resistance within a range of plus or minus a few ppm to several tens of ppm are often used for the resistors 11 and 12. In contrast, the pair of printed wirings 21 and 22 connected to both ends of the pair of series-connected resistors 11 and 12 have a temperature coefficient of resistance of about 4000 ppm when the printed wirings 21 and 22 are made of copper foil.

[0025] In this way, the resistance temperature coefficients of the printed wiring 21 and 22 are several hundred or several thousand times larger than the resistance temperature coefficients of the resistors 11 and 12. Therefore, when the temperature of the resistors 11 and 12 rises or when the temperature of the printed circuit board rises, the temperature of the printed wiring 21 and 22 itself rises, and the resistance values ​​of the printed wiring 21 and 22 become higher than the resistance values ​​of the resistors 11 and 12.

[0026] As a result, the output voltage Vout generated at the connection point N of the resistors 11 and 12 varies from the voltage value (Vin / 1000) determined by the resistance ratio Rr (R1:R2) of the resistors 11 and 12, reducing the output accuracy of the voltage divider circuit 1. The inventors have found that the pair of printed wirings 21 and 22 has an effect on devices that require particularly high-precision detection.

[0027] To address this issue, in the first embodiment, the resistance ratio Rr1 (=R1 / R2) of the resistance value R1 of resistor 11 to the resistance value R2 of resistor 12 is adjusted to be equivalent to the resistance ratio Rl1 (=R3 / R4) of the resistance value R3 of printed wiring 21 to the resistance value R4 of printed wiring 22.

[0028] The above-mentioned "equivalent" does not only mean "substantially identical" or "almost identical," but also includes, for example, those that satisfy the following conditions. Rr1(1-α) < Rl1 < Rr1(1+α)

[0029] Here, the constant α is a positive value less than 1, and is determined, for example, according to the absolute difference between the resistance value R1 of the resistor 11 and the resistance value R2 of the resistor 12. The larger the absolute difference, the smaller the constant α may be. In the first embodiment, in which the resistance ratio between the resistors 11 and 12 is large, it is desirable to set the constant α within the range of, for example, 0.2 to 0.5.

[0030] In the first embodiment, the dimensions of the wiring pattern of at least one of the printed wirings 21 and 22 are adjusted so that the resistance ratio Rl1 of the printed wirings 21 and 22 is equal to the resistance ratio Rr1 of the resistors 11 and 12. As a result, the resistance ratio Rl1 of the printed wirings 21 and 22 becomes equal to the resistance ratio Rr1 of the resistors 11 and 12.

[0031] In the first embodiment, the resistance value R2 of the resistor 12 is lower than the resistance value R1 of the resistor 11. Therefore, from the viewpoint of suppressing fluctuations in the output voltage Vout of the voltage divider circuit 1 due to temperature changes, first, the wiring pattern of the printed wiring 22 is designed so that the resistance value R4 of the printed wiring 22 connected to the other end of the resistor 12, which has a low resistance value, is made as small as possible.

[0032] Next, the wiring pattern of the printed wiring 21, which has a higher degree of design freedom than the printed wiring 22, is adjusted so that the resistance ratio Rl1 of the printed wirings 21 and 22 is equal to the resistance ratio Rr1 of the resistors 11 and 12.

[0033] Specifically, the dimensions of the wiring pattern are adjusted so that the resistance value R3 of the printed wiring 21 becomes the resistance value (R4×Rr1) obtained by multiplying the resistance value R4 of the printed wiring 22 by the resistance ratio Rr1 of the resistor 11 to the resistor 12.

[0034] The wiring pattern may be adjusted by adjusting at least one of the length, width, and thickness of the wiring pattern. In the first embodiment, the length and width of the wiring pattern of the printed wiring 21 are adjusted.

[0035] Furthermore, instead of the resistance ratio Rl1 of the printed wiring 21 to the printed wiring 22, a resistance ratio Rl2 (=R4 / R3) of the resistance value R4 of the printed wiring 22 to the resistance value R3 of the printed wiring 21 may be used as the resistance ratio Rl (R3:R4) of the printed wirings 21 and 22. In this case, a resistance ratio Rr2 (=R2 / R1) of the resistance value R2 of the resistor 12 to the resistance value R1 of the resistor 11 is used as the resistance ratio Rr (R1:R2) of the resistors 11 and 12.

[0036] In this way, the resistance ratio Rl (R3:R4) of the printed wirings 21 and 22 is adjusted to be equal to the resistance ratio Rr (R1:R2) of the resistors 11 and 12 at the same temperature. From another perspective, the ratio of the resistance values ​​of the printed wiring 21 and the resistor 11 and the ratio of the resistance values ​​of the printed wiring 22 and the resistor 12 are adjusted to be equal. As a result, even if the resistance values ​​of the printed wirings 21 and 22, which have a higher resistance temperature coefficient than the resistors 11 and 12, fluctuate when the temperature of the voltage divider circuit 1 rises or falls, the resistance ratio Rl of the printed wirings 21 and 22 is maintained approximately constant.

[0037] This makes it possible to suppress the influence of the printed wirings 21 and 22 on the output voltage Vout of the voltage-divider circuit 1 due to temperature changes in the voltage-divider circuit 1. Therefore, in the first embodiment, it is possible to suppress a decrease in the output accuracy of the voltage-divider circuit 1 due to the influence of the printed wirings 21 and 22.

[0038] In the first embodiment, the output terminal of the buffer circuit 30 is connected to the input terminal 1a of the voltage divider circuit 1, but the buffer circuit 30 may be included in the voltage divider circuit 1 itself.

[0039] FIG. 2 is a diagram schematically showing the wiring pattern of the voltage divider circuit 1 formed on the substrate circuit 100. As shown in FIG.

[0040] 2, resistors 11 and 12 are both realized by chip resistors. An electrode D2 of the first chip resistor corresponding to one end of resistor 11 and an electrode D1 of the second chip resistor corresponding to one end of resistor 12 are connected to each other.

[0041] In addition, one end of printed wiring 21 is connected to electrode D1 of the first chip resistor corresponding to the other end of resistor 11, and one end of printed wiring 22 is connected to electrode D2 of the second chip resistor corresponding to the other end of resistor 12.

[0042] In this example, the resistance value R1 of the resistor 11 is 4950 [Ω], the resistance value R2 of the resistor 12 is 50 [Ω], and the voltage division ratio (R2 / Rt) of the resistors 11 and 12 is 1 / 1000.

[0043] Furthermore, the resistance value R4 of the printed wiring 22 connected to the electrode D2 of the resistor 12, which has the lower resistance value of the resistors 11 and 12, is 50 mΩ. Therefore, the resistance value R3 of the printed wiring 21 connected to the electrode D1 of the resistor 11, which has the higher resistance value, is designed, for example, so that the resistance ratio Rl of the printed wirings 21 and 22 matches the resistance ratio Rr of the resistors 11 and 12.

[0044] Specifically, the width of the printed wiring 21 is narrowed and the length of the wiring pattern is increased so that the resistance R3 of the printed wiring 21 is equal to the resistance ratio Rr1 (R1 / R2) of the resistor 11 to the resistor 12 multiplied by the resistance R4 of the printed wiring 22. This suppresses fluctuations in the output voltage Vout due to temperature changes in the voltage divider circuit 1.

[0045] An output terminal of a buffer circuit 30 that outputs an input voltage Vin is connected to the input terminal 1a of the voltage divider circuit 1, which is the other end of the printed wiring 21. The buffer circuit 30 is arranged in the upstream stage of the printed wiring 21 because the buffer circuit 30 has a sufficiently high input impedance and a sufficiently low output impedance, so that the influence of the internal resistance of the upstream signal supply circuit can be made negligible.

[0046] Therefore, when adjusting the resistance ratio Rl of the printed wirings 21 and 22, it is not necessary to consider the internal resistance of the signal supply circuit upstream of the printed wiring 21, and it is only necessary to consider the resistance values ​​of the printed wirings 21 and 22. This makes it easier to design the resistance ratio Rl of the printed wirings 21 and 22, and makes it possible to appropriately suppress a decrease in the output accuracy of the voltage divider circuit 1.

[0047] FIG. 3 is a flowchart showing a method for manufacturing the voltage divider circuit 1 according to the first embodiment.

[0048] First, in step S1, printed wiring 21 and 22 are formed on a substrate on which a series resistor, which is a pair of resistors 11 and 12 connected in series, is mounted as double-ended wiring connected to both ends of the other ends of the pair of resistors 11 and 12.

[0049] At this time, the resistance value of at least one of the printed wirings 21 and 22 is adjusted, so that the resistance ratio Rl (R3:R4) of the printed wirings 21 and 22 is set to be equivalent to the resistance ratio Rr (R1:R2) of the resistors 11 and 12. In the first embodiment, the dimensions of the wiring pattern of the printed wiring 21 are adjusted so that the resistance ratio Rl of the printed wirings 21 and 22 is equivalent to the resistance ratio Rr of the resistors 11 and 12.

[0050] In step S2, resistors 11 and 12 having different resistance values ​​are mounted on a printed circuit board on which printed wiring 21 and 22 are formed. Specifically, the other end of resistor 11 is electrically connected to printed wiring 21 by soldering, and the other end of resistor 12 is electrically connected to printed wiring 22 by soldering.

[0051] <Modification> 1 and 2 show an example in which the resistance value R1 of the resistor 11 is greater than the resistance value R2 of the resistor 12, but the resistance value R1 of the resistor 11 may be smaller than the resistance value R2 of the resistor 12. This configuration example will be described with reference to FIG.

[0052] Fig. 4 is a diagram showing a modified configuration of the voltage divider circuit 1. The modified configuration shown in Fig. 4 is basically the same as the voltage divider circuit 1 shown in Fig. 1, except that the resistance value R1 of resistor 11 is smaller than the resistance value R2 of resistor 12, and the wiring patterns of printed wirings 21 and 22 are adjusted accordingly.

[0053] 4, it is desirable to make the resistance value of the printed wiring 21 connected to the resistor 11, which has a lower resistance value than the resistor 12, as small as possible. Therefore, in this modification, the dimensions of the wiring pattern of the printed wiring 21 are adjusted by narrowing the width of the printed wiring 21 or lengthening the length of the printed wiring 21 so that the resistance ratio Rl of the printed wirings 21 and 22 matches the resistance ratio Rr of the resistors 11 and 12.

[0054] Specifically, the shape of the wiring pattern is adjusted so that the resistance value R4 of the printed wiring 22 is the resistance value (R3×Rr2) obtained by multiplying the resistance value R3 of the printed wiring 21 by the resistance ratio Rr2 of the resistor 12 to the resistor 11.

[0055] Even with this configuration, it is possible to suppress fluctuations in the output voltage Vout due to temperature changes in the printed wirings 21 and 22, as in the first embodiment.

[0056] Next, the effects of the first embodiment will be described.

[0057] In the first embodiment, the voltage divider circuit 1 has resistors 11 and 12 as a first resistor and a second resistor, one end of which is connected to each other via an output wiring 23 leading to an output terminal 1b corresponding to an output section. The voltage divider circuit 1 also includes a printed wiring 21 corresponding to the first wiring and connected to the other end of the resistor 11, and a printed wiring 22 corresponding to the second wiring and connected to the other end of the resistor 12.

[0058] In this configuration, the resistance value R1 of the resistor 11 and the resistance value R2 of the resistor 12 are different from each other, and the resistance ratio Rr of the resistors 11 and 12 and the resistance ratio Rl of the printed wiring 21 and printed wiring 22 are equal to each other.

[0059] Moreover, the substrate circuit 100 in the first embodiment includes a voltage dividing circuit 1, and the printed wirings 21 and 22 are wiring patterns formed on the substrate circuit 100.

[0060] Furthermore, in the manufacturing method of the voltage divider circuit 1 of the first embodiment, the resistance value of the resistor 11 and the resistance value of the resistor 12 are different from each other, and the resistance ratio Rl of the printed wirings 21 and 22 is set to be equal to the resistance ratio Rr of the resistors 11 and 12.

[0061] According to the voltage divider circuit 1, the substrate circuit 100, and the method for manufacturing the voltage divider circuit 1, the absolute difference between the resistance ratio Rr of the resistors 11 and 12 and the resistance ratio Rl of the printed wiring 21 and 22 is small. As a result, even when the temperatures of the printed wiring 21 and 22 rise and fall, the ratio between the sum of the resistance values ​​of the resistors 11 and 12 and the sum of the resistance values ​​of the resistors 12 and 22 is maintained equal to the resistance ratio Rr of the resistors 11 and 12.

[0062] This makes it possible to suppress fluctuations in the output voltage Vout generated at the connection point N of the resistors 11 and 12, one end of which is connected to the other via the output wiring 23, due to temperature changes in the printed wiring 21 and 22 formed on the substrate circuit 100. This makes it possible to suppress a decrease in the output accuracy of the voltage divider circuit 1, which is caused by the influence of the printed wiring 21 and 22 connected to the other end of each of the pair of resistors 11 and 12 connected in series.

[0063] From another perspective, the ratio of the resistance value between the printed wiring 21 and the resistor 11 is equal to the ratio of the resistance value between the printed wiring 22 and the resistor 12.

[0064] Even with this configuration, the absolute difference between the resistance ratio Rr of resistors 11 and 12 and the resistance ratio Rl of printed wiring 21 and printed wiring 22 is small, so fluctuations in the output voltage Vout due to temperature changes in the printed wirings 21 and 22 can be accurately suppressed.

[0065] Furthermore, in the voltage divider circuit 1 of the first embodiment, the printed wiring 21 and the printed wiring 22 are different from each other in at least one of the length, width, and thickness of the wiring patterns. By adjusting the dimensions of the wiring patterns in this manner, the resistance ratio Rl of the printed wirings 21 and 22 can be adjusted.

[0066] In particular, in the first embodiment, the printed wiring 21 of the resistor 11, which has a higher resistance value among the resistors 11 and 12, has a wiring pattern that is longer, narrower, or thinner than the printed wiring 22 of the resistor 12, which has a lower resistance value.

[0067] According to this configuration, the resistance ratio Rl between the wiring pattern of the printed wiring 21 connected to the resistor 11 with a high resistance value and the wiring pattern of the printed wiring 22 connected to the resistor 12 with a low resistance value is adjusted, so that the influence of temperature changes on the printed wirings 21 and 22 can be suppressed without reducing the accuracy of the output voltage Vout.

[0068] In the voltage divider circuit 1 of the first embodiment, the input terminal 1a of the printed wiring 21 is connected to the output terminal of the buffer circuit 30, and the output terminal of the printed wiring 22 is connected to the reference potential Vref. The connection point N between the resistors 11 and 12 is connected to the output terminal 1b of the voltage divider circuit 1.

[0069] According to this configuration, it is possible to divide the input voltage Vin with a simple circuit configuration, while suppressing a decrease in the output accuracy of the divided output voltage Vout.

[0070] Second Embodiment FIG. 5 is a diagram showing an example of the configuration of the voltage dividing circuit 2 according to the second embodiment.

[0071] The voltage divider circuit 2 is configured by an inverting amplifier circuit, and includes two series resistor circuits 10A having the same circuit configuration as the voltage divider circuit 1 of the first embodiment, and an amplifier 31.

[0072] The series resistance circuit 10A includes a pair of resistors 11 and 12 connected in series, printed wiring 21 and 22, and an output wiring 23 connected to a connection point N1 between the resistors 11 and 12. The output wiring 23 is a wiring leading to an output terminal 2b corresponding to the output portion of the voltage divider circuit 2, and connects the resistors 11 and 12 to each other.

[0073] In the series resistance circuit 10A, the resistance value R1 of the resistor 11 is higher than the resistance value R2 of the resistor 12. Similarly to the first embodiment, the resistance ratio Rl of the printed wirings 21 and 22 is set to be equal to the resistance ratio Rr of the resistors 11 and 12.

[0074] One end (input end) of the printed wiring 21 is connected to the output terminal of the amplifier 31, and one end of the output wiring 23 is connected to the inverting input terminal (-) of the amplifier 31. The output end of the printed wiring 22 is connected to a reference potential Vref.

[0075] The amplifier 31 is an operational amplifier that amplifies an input voltage Vin input to a non-inverting input terminal (+). The non-inverting input terminal (+) of the amplifier 31 is connected to an input terminal 2a of the voltage divider circuit 2, and the output terminal of the amplifier 31 is connected to an output terminal 2b of the voltage divider circuit 2.

[0076] As described above, the voltage-divider circuit 2 includes the series resistance circuit 10A and the amplifier 31. Similar to the voltage-divider circuit 1 of the first embodiment, the series resistance circuit 10A can suppress output fluctuations at the connection point N1 that occur due to temperature changes in the voltage-divider circuit 2. Therefore, fluctuations in the output voltage Vout are suppressed, and a decrease in the output accuracy of the voltage-divider circuit 2 can be suppressed.

[0077] FIG. 6 is a diagram schematically showing the wiring pattern of the voltage dividing circuit 2. As shown in FIG.

[0078] In the example shown in Fig. 6, the series resistor circuit 10A has the same configuration as the voltage divider circuit 1 shown in Fig. 3. Specifically, resistors 11 and 12 are both realized by chip resistors. An electrode D2 of a first chip resistor corresponding to one end of resistor 11 and an electrode D1 of a second chip resistor corresponding to one end of resistor 12 are connected to each other via output wiring 23, which is a printed wiring.

[0079] In addition, one end of printed wiring 21 is connected to electrode D1 of the first chip resistor corresponding to the other end of resistor 11, and one end of printed wiring 22 is connected to electrode D2 of the second chip resistor corresponding to the other end of resistor 12.

[0080] In this example, the resistance value R1 of resistor 11 is 9 kΩ, and the resistance value R2 of resistor 12 is 1 kΩ. Since the resistance value R1 of resistor 11 is nine times the resistance value R2 of resistor 12, the resistance value R3 of printed wiring 21 is set to a resistance value (9X) nine times the resistance value R4 of printed wiring 22. This suppresses fluctuations in the output voltage Vout due to temperature changes in voltage divider circuit 2.

[0081] The voltage divider circuit 2 of the second embodiment has a series resistance circuit 10A corresponding to the voltage divider circuit 1 of the first embodiment. The series resistance circuit 10A includes resistors 11 and 12 connected at one end to each other, a printed wiring 21 connected to the other end of the resistor 11, and a printed wiring 22 connected to the other end of the resistor 12. The resistors 11 and 12 have different resistance values, and the resistance ratio Rr of the resistors 11 and 12 and the resistance ratio Rl of the printed wiring 21 and 22 are equal.

[0082] Furthermore, the voltage divider circuit 2 includes an amplifier 31 whose output terminal is connected to an output end 2b corresponding to the output section of the voltage divider circuit 2. An output wiring 23 connecting the resistors 11 and 12 to each other includes a connection point N1 between the resistors 11 and 12 and is connected to the inverting input terminal (-) of the amplifier 31, and the input end of the printed wiring 21 is connected to the output terminal of the amplifier 31. Furthermore, the resistance value R1 of the resistor 11 is higher than the resistance value R2 of the resistor 12.

[0083] The wiring of the pair of resistors 11 and 12 that constitute the inverting amplifier circuit can also be configured in the same manner as in the first embodiment. With this configuration, it is possible to suppress fluctuations in voltage occurring at the connection point N1 of the resistors 11 and 12 due to temperature changes in the printed wiring 21 and 22, just like in the first embodiment.

[0084] (Third embodiment) FIG. 7 is a diagram showing an example of the configuration of the voltage dividing circuit 3 according to the third embodiment.

[0085] The voltage divider circuit 3 is configured as a two-stage voltage divider circuit 2 of the second embodiment. More specifically, the voltage divider circuit 3 is configured as a two-stage inverting amplifier circuit, and includes two sets of series resistor circuits 10A and 10B, an amplifier 31, and an amplifier 32, which have the same circuit configuration as the voltage divider circuit 1 of the first embodiment.

[0086] The first-stage inverting amplifier circuit is a first voltage divider circuit and is composed of a series resistor circuit 10A and an amplifier 31, and the second-stage inverting amplifier circuit is a second voltage divider circuit and is composed of a series resistor circuit 10B and an amplifier 32.

[0087] The series resistance circuit 10A includes a first set of resistors 11 and 12 connected in series, printed wiring 21 and 22, and an output wiring 23 connected to a connection point N1 between the resistors 11 and 12. The output wiring 23 includes the connection point N1 and is a wiring leading to an output terminal 3b corresponding to the output portion of the voltage divider circuit 3, and connects the resistors 11 and 12 to each other.

[0088] In the series resistor circuit 10A, the resistance ratio Rl of the printed wirings 21 and 22 is set to be equal to the resistance ratio Rr of the resistors 11 and 12, as in the first embodiment.

[0089] One end (input end) of the printed wiring 21 is connected to the output terminal of the amplifier 31, and one end of the output wiring 23 is connected to the inverting input terminal (-) of the amplifier 31. The output end of the printed wiring 22 is connected to a reference potential Vref.

[0090] The amplifier 31 is an operational amplifier that amplifies the input voltage Vin input to the non-inverting input terminal (+). The non-inverting input terminal (+) of the amplifier 31 is connected to the input terminal 3a of the voltage divider circuit 3.

[0091] The series resistance circuit 10B has a second set of resistors 11 and 12 connected in series, printed wiring 21 and 22, and an output wiring 23 connected to a connection point N2 between the resistors 11 and 12. The output wiring 23 is a wiring that includes the connection point N2 and leads to an output terminal 3b that corresponds to the output portion of the voltage divider circuit 3, and connects the resistors 11 and 12 to each other.

[0092] In the series resistance circuit 10B, similarly to the series resistance circuit 10A, the resistance ratio Rl of the printed wirings 21 and 22 is set to be equal to the resistance ratio Rr of the resistors 11 and 12.

[0093] One end (input end) of the printed wiring 21 is connected to the output terminal of the amplifier 32, and one end of the output wiring 23 is connected to the inverting input terminal (-) of the amplifier 32. The output end of the printed wiring 22 is connected to the output terminal of the amplifier 31 of the series resistance circuit 10A.

[0094] The amplifier 32 is an operational amplifier that amplifies the output voltage of the amplifier 31 in accordance with the resistance ratio Rr of the resistors 11 and 12 of the series resistor circuit 10B. A reference potential Vref is connected to the non-inverting input terminal (+) of the amplifier 32, and the output terminal of the amplifier 32 is connected to an output terminal 3b that corresponds to the output section of the voltage divider circuit 3. The amplifier 32 outputs the amplified voltage as an output voltage Vout to the output terminal 3b.

[0095] Specifically, the amplifier 32 amplifies the input voltage Vin input to the inverting input terminal (-) in accordance with the relationship shown in the following equation between the resistance value R1 of the resistor 11 and the resistance value R2 of the resistor 12, and outputs the amplified voltage as the output voltage Vout. Vout = (-R1 / R2) × Vin

[0096] As described above, the voltage-divider circuit 3 includes two series resistor circuits 10A and 10B and two amplifiers 31 and 32. Similar to the voltage-divider circuit 1 of the first embodiment, the two series resistor circuits 10A and 10B can suppress output fluctuations at the connection points N1 and N2 that occur due to temperature changes in the voltage-divider circuit 3. Therefore, fluctuations in the output voltage Vout are suppressed, and a decrease in the output accuracy of the voltage-divider circuit 3 can be suppressed.

[0097] FIG. 8 is a diagram schematically showing the wiring pattern of the voltage dividing circuit 3. As shown in FIG.

[0098] In the example shown in FIG. 8, each of the series resistance circuits 10A and 10B has the same configuration as the voltage divider circuit 1 shown in FIG.

[0099] Specifically, both resistors 11 and 12 are realized by chip resistors. An electrode D2 of the first chip resistor corresponding to one end of resistor 11 and an electrode D1 of the second chip resistor corresponding to one end of resistor 12 are connected to each other. One end of a printed wiring 21 is connected to the electrode D1 of the first chip resistor corresponding to the other end of resistor 11, and one end of a printed wiring 22 is connected to the electrode D2 of the second chip resistor corresponding to the other end of resistor 12.

[0100] In this example, the resistance value R1 of resistor 11 is 9 kΩ, and the resistance value R2 of resistor 12 is 1 kΩ. Since the resistance value R1 of resistor 11 is nine times the resistance value R2 of resistor 12, the resistance value R3 of printed wiring 21 is set to a resistance value (9X) nine times the resistance value R4 of printed wiring 22. This suppresses fluctuations in the output voltage Vout due to temperature changes in the voltage divider circuit 3.

[0101] Although the third embodiment has been described as including two sets of series resistance circuits 10A and 10B and amplifiers 31 and 32, three or more sets of series resistance circuits and amplifiers may be used. Even in this configuration, fluctuations in output voltage due to temperature changes in the series resistance circuits can be suppressed.

[0102] Fig. 9 is a diagram illustrating an example of an implementation of the voltage divider circuit 3 according to the third embodiment. Fig. 9 shows a resistor assembly 40 in which a plurality of resistors are packaged, and two resistors in the resistor assembly 40 are used as resistors 11 and 12 of a series resistor circuit 10A.

[0103] 9, an output wiring 23 is formed from a terminal T3 of the resistor group 40 to the inverting input terminal (-) of the amplifier 31. Then, a printed wiring 21 is formed from a terminal T1 of the resistor group 40 to the output terminal of the amplifier 31, and a printed wiring 22 is formed from a terminal T2 of the resistor group 40 to a signal line to which a reference potential Vref is supplied.

[0104] In this example, the wiring pattern of the printed wiring 21 is designed so that the resistance ratio Rl of the printed wirings 21 and 22 is equal to the value of the resistance ratio Rr of the resistors 11 and 12 .

[0105] Next, the effects of the third embodiment will be described.

[0106] In the third embodiment, the voltage-dividing circuit 3 includes a series resistance circuit 10A as a first dividing circuit including a first set of resistors 11 and 12 and a first amplifier 31, and a series resistance circuit 10B as a second voltage-dividing circuit including a second set of resistors 11 and 12 and a second amplifier 32. That is, the voltage-dividing circuit 3 includes a plurality of sets of resistors 11 and 12 and amplifiers.

[0107] As described above, the first set of output wiring 23 is a printed wiring that includes the connection point N1 of the first set of resistors 11 and 12 and connects the first set of resistors 11 and 12 to each other. The first set of output wiring 23 is connected to the inverting input terminal (-) of the amplifier 31, and the input end of the printed wiring 21 connected to the other end of the first set of resistors 11 is connected to the output terminal of the amplifier 31. The output end of the printed wiring 22 connected to the other end of the second set of resistors 12 is connected to the output terminal of the first set of amplifier 31.

[0108] Furthermore, the second set of output wiring 23 is a printed wiring that includes a connection point N2 of the second set of resistors 11 and 12 and connects the second set of resistors 11 and 12 to each other. The second set of output wiring 23 is connected to the inverting input terminal (-) of the amplifier 32, and the input terminal of the printed wiring 21 connected to the other end of the second set of resistors 11 is connected to the output terminal of the amplifier 32. The output terminal of the amplifier 32 is connected to an output terminal 3b that corresponds to the output portion of the voltage divider circuit 3.

[0109] In this way, even in a circuit configuration in which multiple inverting amplifier circuits are connected, it is possible to suppress fluctuations in voltage occurring at each of the connection points N1 and N2 of each pair of resistors 11 and 12 due to temperature changes in the printed wiring 21 and 22.

[0110] FIG. 10 is a diagram showing an application example of the voltage divider circuit 3 according to the third embodiment.

[0111] The measuring device 110 is a device for calculating a measured value of an electrical physical quantity, such as current, voltage, or power, generated in a measurement target, based on the output signal of a current sensor 111 and the output signal of a voltage sensor 112. The measuring device 110 includes a substrate circuit 100, on which a voltage divider circuit 1 of the first embodiment and a voltage divider circuit 3 of the third embodiment are formed. For example, at least one of the voltage divider circuits 1 and 3 divides the output signal of the voltage sensor 112 as an input voltage Vin.

[0112] In this way, at least one of the voltage divider circuits 1 and 3 of the first and third embodiments can be applied to the electronic circuit of the measuring device 110, for example.

[0113] The measuring device 110 includes at least one of the voltage divider circuit 1 of the first embodiment and the voltage divider circuit 3 of the third embodiment, thereby making it possible to suppress fluctuations in the output voltage Vout that accompany temperature changes in the printed wirings 21 and 22. This makes it possible to suppress a decrease in the measurement accuracy of the measuring device 110.

[0114] In the third embodiment, an example in which both voltage divider circuits 1 and 3 are applied has been described, but this is not limiting, and at least one of the voltage divider circuits 1 to 3 of the first to third embodiments may be applied to the electronic circuit of the measuring device 110.

[0115] (Fourth embodiment) In the above embodiment, an example has been described in which the resistance ratio Rl of the printed wirings 21 and 22 is adjusted by focusing on the resistance ratio Rr of the resistors 11 and 12. However, there are cases in which not only the DC resistance components but also the inductance components of the printed wirings 21 and 22 change due to temperature changes in the printed wirings 21 and 22. A countermeasure for this will be described in the following fourth embodiment.

[0116] Fig. 11 is a diagram showing an example of the configuration of a voltage-dividing circuit 4 according to the fourth embodiment. The voltage-dividing circuit 4 has basically the same configuration as the voltage-dividing circuit 1 shown in Fig. 1, and differs from the configuration of the voltage-dividing circuit 1 only in the wiring pattern of the printed wiring 22a.

[0117] In the fourth embodiment, the resistance value R1 of the resistor 11 is smaller than the resistance value R2 of the resistor 12, for example, the resistance value R1 is 2 [kΩ] and the resistance value R2 is 1 [kΩ].

[0118] The printed wirings 21 and 22 have an inductance component in addition to a DC resistance component. In Fig. 11, an inductance value L3 of the printed wiring 21 and an inductance value L4 of the printed wiring 22 are shown.

[0119] As with the DC resistance component, the influence of the inductance component due to temperature changes of the printed wirings 21 and 22 can also be suppressed by adjusting the inductance ratio Ll (L3:L4) of the printed wirings 21 and 22. The inductance ratio (L3:L4) of the printed wirings 21 and 22 refers to the ratio between the inductance value L3 of the printed wiring 21 and the inductance value L4 of the printed wiring 22.

[0120] In the voltage divider circuit 4 of the fourth embodiment, the inductance ratio Ll (L3:L4) of the printed wirings 21 and 22 is adjusted to a value within a specific range centered on the resistance ratio Rr (R1:R2) of the resistors 11 and 12.

[0121] 11, the wiring pattern of the printed wiring 22a is formed in a serpentine shape so that the inductance ratio Ll2 (L4 / L3) of the printed wiring 22 to the printed wiring 21 matches the resistance ratio Rr2 (R2 / R1) of the resistor 12 to the resistor 11. For example, the inductance value L3 is 20 [nH], and the inductance value L4 is 10 [nH].

[0122] In this way, by forming the wiring pattern of the printed wiring 22a in a meandering shape, the inductance value L4 can be made smaller than when the wiring pattern is formed in a straight line, and therefore it is possible to adjust the inductance ratio Ll1. Alternatively, the printed wiring 21 may be formed in a coil shape to increase the inductance value L3 of the printed wiring 21.

[0123] Next, the effects of the fourth embodiment will be described.

[0124] In the voltage divider circuit 4 of the fourth embodiment, the resistance ratio Rl of the printed wirings 21 and 22 is equal to the resistance ratio Rr of the resistors 11 and 12, and the inductance ratio Ll of the printed wirings 21 and 22 is also equal to the resistance ratio Rr of the resistors 11 and 12.

[0125] As a result, even if the input voltage Vin of the voltage dividing circuit 4 is a voltage signal having an AC component, the influence of the inductance components of the printed wirings 21 and 22 due to temperature changes is suppressed, and fluctuations in the output voltage Vout can be reduced.

[0126] 11, the printed wiring 21 is linear, whereas the printed wiring 22a is serpentine. Therefore, the printed wiring 21 and the printed wiring 22 have different wiring pattern shapes.

[0127] According to this configuration, by changing the shape of the wiring pattern of at least one of the printed wirings 21 and 22, the inductance ratio Ll of the printed wirings 21 and 22 can be appropriately adjusted to the resistance ratio Rr of the resistors 11 and 12.

[0128] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0129] For example, although the input terminal 1a of the voltage divider circuit 1 in the first embodiment is connected to the output terminal of the buffer circuit 30, it may be connected to the output terminal of the signal supply circuit. In this case, it is desirable to consider the internal resistance of the signal supply circuit in addition to the resistance value R3 of the printed wiring 21.

[0130] Furthermore, the voltage divider circuits 2 and 3 of the second and third embodiments have circuit configurations in which the resistance value R1 of the resistor 11 is higher than the resistance value R2 of the resistor 12, but may have a circuit configuration in which the resistance value R1 of the resistor 11 is lower than the resistance value R2 of the resistor 12. Even with such a circuit configuration, the same effects as those of the second and third embodiments described above can be achieved. [Explanation of symbols]

[0131] 100 PCB circuit 110 Measuring equipment 1~4 Voltage divider circuit 10A, 10B series resistor circuit (voltage divider circuit) 11, 12 Resistor (first resistor, second resistor) 21, 22, 22a Printed wiring (first wiring, second wiring) 30 Buffer circuit 31, 32 Amplifier (first amplifier, second amplifier)

Claims

1. A voltage divider circuit having a first resistor and a second resistor, one ends of which are connected to each other via an output wiring connected to an output portion of the circuit, a first wiring connected to the other end of the first resistor; a second wiring connected to the other end of the second resistor, the resistance value of the first resistor and the resistance value of the second resistor are different from each other; a resistance ratio between the first resistor and the second resistor is equal to a resistance ratio between the first wiring and the second wiring; Voltage divider circuit.

2. 2. The voltage divider circuit according to claim 1, a resistance ratio between the first wiring and the first resistor is equal to a resistance ratio between the second wiring and the second resistor; Voltage divider circuit.

3. 2. The voltage divider circuit according to claim 1, The first wiring and the second wiring are different from each other in at least one of length, width, and thickness of the wiring pattern. Voltage divider circuit.

4. 4. The voltage divider circuit according to claim 3, The wiring of the resistor having a higher resistance value among the first resistor and the second resistor has a wiring pattern that is longer, narrower, or thinner than the wiring of the resistor having a lower resistance value. Voltage divider circuit.

5. 2. The voltage divider circuit according to claim 1, an inductance ratio between the first wiring and the second wiring is equal to a resistance ratio between the first resistor and the second resistor; Voltage divider circuit.

6. 6. The voltage divider circuit according to claim 5, The first wiring and the second wiring have different wiring pattern shapes. Voltage divider circuit.

7. 2. The voltage divider circuit according to claim 1, an input end of the first wiring is connected to an output end of a buffer circuit; The output end of the second wiring is connected to a reference potential, the output wiring connecting the first resistor and the second resistor to each other is connected to the output portion of the voltage divider circuit; Voltage divider circuit.

8. 2. The voltage divider circuit according to claim 1, an amplifier having an output terminal connected to the output of the circuit; the output wiring connecting the first resistor and the second resistor to each other is connected to an inverting input terminal of the amplifier; The input end of the first wiring is connected to the output terminal of the amplifier. Voltage divider circuit.

9. 2. The voltage divider circuit according to claim 1, a plurality of pairs of the first resistor and the second resistor and an amplifier; the output wiring connecting the first resistor and the second resistor in the first set to each other is connected to an inverting input terminal of a first amplifier of a first voltage divider circuit; the output wiring connecting the first resistor and the second resistor in the second set to each other is connected to an inverting input terminal of a second amplifier in a second voltage dividing circuit; an input end of the first wiring connected to the other end of the first resistor in the first set is connected to an output terminal of the first amplifier; an output end of the second wiring connected to the other end of the second resistor in the second set is connected to an output terminal of the first amplifier; an input end of the first wiring connected to the other end of the first resistor in the second set is connected to an output terminal of the second amplifier; the output terminal of the second amplifier is connected to the output of the circuit; Voltage divider circuit.

10. A measuring device comprising the voltage divider circuit according to any one of claims 1 to 9.

11. A voltage divider circuit according to any one of claims 1 to 9, the first wiring and the second wiring are wiring patterns formed on a substrate; Board circuit.

12. A method for manufacturing a voltage divider circuit including a first resistor and a second resistor, one ends of which are connected to each other via an output wiring connected to an output section, a first wiring connected to the other end of the first resistor, and a second wiring connected to the other end of the second resistor, the resistance value of the first resistor and the resistance value of the second resistor are different from each other; A method for manufacturing a voltage divider circuit in which a resistance ratio between the first wiring and the second wiring is set to be equal to a resistance ratio between the first resistor and the second resistor.

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