Attenuator

Abstract

To improve frequency characteristics.SOLUTION: An attenuator 10 includes a resistor-capacitor unit 13 in which a plurality of stages each of which is configured by parallel connection of a resistor and a capacitor is connected in series, and a load resistor and a load capacitor connected in parallel. The resistor-capacitor unit 13 is connected between an input terminal 11 and an output terminal 12. The load resistor and the load capacitor are connected between the output terminal 12 and the ground. A resistance value of the resistor and a capacitance value of the capacitor of the resistor-capacitor unit 13 are adjusted such that a time constant of the resistor and the capacitor of each stage is equal to a time constant of the impedance as seen from a node on the output terminal 12 side of each stage to the output terminal 12 side, and the impedance is calculated while including a parasitic capacitance Cx between both ends of each stage and the ground.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to an attenuator. [Background technology]

[0002] Conventionally, attenuators that consist of multiple stages of resistors and other components connected in series are known. Although the withstand voltage of a single component is limited, an attenuator that consists of multiple stages of components connected in series like this can handle high voltage inputs.

[0003] For example, Patent Document 1 discloses an attenuator in which resistors are connected in series in multiple stages, and the resistance value is variable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 62-196417 Summary of the Invention [Problem to be solved by the invention]

[0005] 18 shows an example of a schematic configuration of a conventional attenuator 200. The attenuator 200 includes resistors R1 to R10 connected in series and a load resistor RL. A signal is input to an input terminal 11 of the attenuator 200, and a signal is output from an output terminal 12.

[0006] 18, a parasitic capacitance Cx usually occurs between the resistors R1 to R10 and the ground. In that case, a low-pass filter is formed by the resistors R1 to R10 and the parasitic capacitance Cx, and the amplification factor (gain) of the attenuator 200 decreases with frequency.

[0007] Fig. 19 shows an example of the frequency characteristics of the conventional attenuator 200. Fig. 19 shows an example in which the component values ​​in the configuration shown in Fig. 18 are set as follows. In this case, the attenuator 200 has an amplification factor of 1 / 1000. R1~R10=1.0[MΩ] RL=10.01[kΩ] Cx=1.0[pF]

[0008] Referring to FIG. 19, it can be seen that the amplification factor starts to decrease when the frequency exceeds a few kHz.

[0009] It is desirable for an attenuator to have a constant amplification factor regardless of frequency.

[0010] Therefore, an object of the present disclosure is to provide an attenuator capable of improving frequency characteristics. [Means for solving the problem]

[0011] According to some embodiments, an attenuator includes a resistor-capacitor unit in which a plurality of stages, each of which is composed of a parallel connection of a resistor and a capacitor, are connected in series, and a load resistor and a load capacitor connected in parallel, the resistor-capacitor unit is connected between an input terminal and an output terminal, the load resistor and the load capacitor are connected between the output terminal and ground, and the resistance value of the resistor and the capacitance value of the capacitor of the resistor-capacitor unit are adjusted so that the time constant of the resistor and the capacitor of each stage is equal to the time constant of the impedance when the output terminal side is viewed from the node on the output terminal side of each stage, and the impedance is calculated including the parasitic capacitance between both ends of each stage and the ground. Such an attenuator can improve the frequency characteristics.

[0012] In an attenuator according to an embodiment, the resistors in the resistor-capacitor unit may all have the same resistance value, and the capacitors in the resistor-capacitor unit may all have different capacitance values, thereby improving frequency characteristics by adjusting only the capacitance value without adjusting the resistance value.

[0013] In an attenuator according to one embodiment, the capacitance value of a capacitance when looking at the output terminal side from a node on the output terminal side of each stage may be calculated based on the following equations (1) and (2).

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[0014] In the attenuator according to one embodiment, the capacitance value of the capacitor of the resistor-capacitor unit may be calculated based on the following equations (3) and (4).

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[0015] In the attenuator according to one embodiment, the resistors in the resistor-capacitor unit may all have different resistance values, and the capacitors in the resistor-capacitor unit may all have the same capacitance value, thereby improving the frequency characteristics by adjusting only the resistance values ​​without adjusting the capacitance values.

[0016] In the attenuator according to one embodiment, the resistance value of the resistor of the resistor-capacitor unit may be calculated based on the following equations (7) and (8).

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[0017] According to the present disclosure, it is possible to provide an attenuator capable of improving frequency characteristics. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an attenuator according to a comparative example. [Diagram 2] 11 is a diagram showing an example of resistance values ​​and capacitance values ​​of an attenuator according to a comparative example; FIG. [Diagram 3] FIG. 11 is a diagram illustrating an example of frequency characteristics of an attenuator according to a comparative example. [Figure 4] 11 is a diagram illustrating an example of impedance of each stage of an attenuator according to a comparative example. FIG. [Diagram 5] 11 is a diagram showing an example of impedance to ground of each stage of an attenuator according to a comparative example; FIG. [Figure 6] FIG. 11 is a diagram showing an example of normalized impedance to ground of each stage of an attenuator according to a comparative example. [Figure 7] 11 is a diagram showing an example of a voltage applied to each stage of the attenuator according to the comparative example. FIG. [Figure 8] FIG. 1 is a diagram showing a schematic configuration of an attenuator according to an embodiment; [Figure 9] 11 is a diagram showing an example of resistance values ​​and capacitance values ​​when the capacitance value is adjusted in an attenuator according to an embodiment. FIG. [Figure 10] 11 is a diagram showing an example of impedance to ground of each stage when the capacitance value is adjusted in an attenuator according to an embodiment. FIG. [Figure 11] 11 is a diagram showing an example of impedance of each stage when a capacitance value is adjusted in an attenuator according to an embodiment. FIG. [Figure 12] 11 is a diagram showing an example of a voltage applied to each stage when a capacitance value is adjusted in an attenuator according to an embodiment. FIG. [Figure 13] 11 is a diagram showing an example of frequency characteristics when a capacitance value is adjusted in an attenuator according to an embodiment. FIG. [Figure 14] 11 is a diagram showing an example of resistance values ​​and capacitance values ​​when the resistance value is adjusted in an attenuator according to an embodiment. FIG. [Figure 15] 11 is a diagram showing an example of impedance to ground of each stage when a resistance value is adjusted in an attenuator according to an embodiment; FIG. [Figure 16] FIG. 11 is a diagram showing an example of normalized impedance to ground of each stage when a resistance value is adjusted in an attenuator according to an embodiment. [Figure 17]11 is a diagram showing an example of a voltage applied to each stage when a resistance value is adjusted in an attenuator according to an embodiment. FIG. [Figure 18] FIG. 1 is a diagram showing an example of a schematic configuration of a conventional attenuator. [Figure 19] FIG. 1 is a diagram illustrating an example of frequency characteristics of a conventional attenuator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (Comparative Example) First, an attenuator according to a comparative example will be described. Fig. 1 is a diagram showing a schematic configuration of an attenuator 100 according to a comparative example.

[0020] The attenuator 100 according to the comparative example includes a resistor-capacitor unit 13, a load resistor RL, and a load capacitor CL. The load resistor RL and the load capacitor CL are connected in parallel.

[0021] The resistor-capacitor unit 13 includes resistors R1 to R10 and capacitors C1 to C10. The resistor R1 and the capacitor C1 are connected in parallel. Similarly, the resistors R2 to R10 are connected in parallel to the capacitors C2 to C10, respectively.

[0022] Hereinafter, the configuration in which resistor R1 and capacitor C1 are connected in parallel, the configuration in which resistor R2 and capacitor C2 are connected in parallel, ..., the configuration in which resistor R10 and capacitor C10 are connected in parallel may be referred to as "each stage" in the following description. Resistor-capacitor unit 13 is configured with each stage connected in series in multiple stages. In the example shown in Fig. 1, resistor-capacitor unit 13 is configured with each stage connected in series in ten stages.

[0023] The resistor-capacitor unit 13 is connected between the input terminal 11 and the output terminal 12. A load resistor RL and a load capacitor CL are connected between the output terminal 12 and ground.

[0024] In the attenuator 100 according to the comparative example, a signal is input to an input terminal 11 and a signal is output from an output terminal 12 .

[0025] The attenuator 100 according to the comparative example differs from the conventional attenuator 200 shown in Fig. 18 in that capacitors C1 to C10 and a load capacitor CL are added. Since the capacitors C1 to C10 and the load capacitor CL are added, the attenuator 100 according to the comparative example does not exhibit characteristics as a low-pass filter even if there is a parasitic capacitance Cx. In other words, the attenuator 100 according to the comparative example does not decrease in amplification factor even at high frequencies.

[0026] Fig. 2 shows an example of the resistance values ​​of resistors R1 to R10 and the capacitance values ​​of capacitors C1 to C10 of the attenuator 100 according to the comparative example. In the example shown in Fig. 2, the resistance values ​​of resistors R1 to R10 are all 1.0 [MΩ]. The capacitance values ​​of capacitors C1 to C10 are all 10 [pF]. The resistance value of load resistor RL is 10.01 [kΩ]. The capacitance value of load capacitor CL is 271.4 [pF]. The capacitance value of parasitic capacitance Cx is 1.0 [pF].

[0027] FIG. 3 shows the frequency characteristics of the attenuator 100 according to the comparative example when the component values ​​of the attenuator 100 are as shown in FIG.

[0028] Referring to Fig. 3, a dip occurs around a few tens of kHz, but apart from this dip, the amplification factor remains constant even at high frequencies. In other words, the attenuator 100 according to the comparative example does not exhibit the characteristics of a low-pass filter, and the amplification factor does not decrease even at high frequencies. Note that in Fig. 3, the dip occurring around a few tens of kHz is believed to be due to the influence of parasitic capacitance Cx. Note that the "dip" referred to here means the portion where the amplification factor decreases around a few tens of kHz.

[0029] The reason why a dip occurs in the vicinity of several tens of kHz as shown in FIG. 3 in the attenuator 100 according to the comparative example will be described below.

[0030] Fig. 4 is a diagram showing the impedance of each stage of the attenuator 100 according to the comparative example. In Fig. 4, the impedances of the first, fifth and tenth stages are shown. For example, Z1 is the impedance of a parallel connection of a resistor R1 and a capacitor C1. Z5 is the impedance of a parallel connection of a resistor R5 and a capacitor C5. Z10 is the impedance of a parallel connection of a resistor R10 and a capacitor C10.

[0031] Since the resistors R1 to R10 all have the same value and the capacitors C1 to C10 all have the same value, the impedances of the i-th stages all have the same frequency characteristics (1≦i≦10).

[0032] Hereinafter, the term "impedance to ground" will be used to refer to the impedance when looking at the output terminal 12 side from the node on the output terminal 12 side of each stage. g1 ~Z g10 This shows that.

[0033] For example, the impedance to ground of the 10th stage is Z g10 is the impedance when looking at the output terminal 12 side from the node on the output terminal 12 side of the parallel connection of the resistor R10 and the capacitor C10 of each stage of the 10th stage. That is, the impedance to ground Z g10 is the impedance due to the parasitic capacitance Cx, the load resistance RL and the load capacitor CL.

[0034] For example, the impedance to ground of the 9th stage, Z g9 is the impedance when looking at the output terminal 12 side from the node on the output terminal 12 side of the parallel connection of the resistor R9 and the capacitor C9 of each stage of the ninth stage. That is, the impedance to ground Z g9 is the impedance due to the resistor R10, the capacitor C10, the two parasitic capacitances Cx, the load resistor RL and the load capacitor CL.

[0035] FIG. 5 is a diagram showing the impedance to ground of each stage of the attenuator 100 according to the comparative example. In FIG. 5, the impedance to ground of the first stage, the fifth stage, and the tenth stage are shown. For example, Z g1 is the impedance to ground of the first stage. Z g5 is the impedance to ground of the fifth stage. Z g10 is the impedance to ground of the 10th stage.

[0036] Fig. 6 is a diagram showing the normalized impedance to ground of each stage of the attenuator 100 according to the comparative example. Here, the normalized impedance to ground is obtained by dividing the impedance to ground by the impedance to ground in DC. Fig. 6 shows the normalized impedance to ground of the first stage, the fifth stage, and the tenth stage.

[0037] Referring to FIG. 4, the impedance of each stage of the attenuator 100 according to the comparative example exhibits the same characteristics for all stages from the first stage to the tenth stage.

[0038] 6, the normalized impedance to ground of the attenuator 100 according to the comparative example starts to decrease at different frequencies for each stage. This is believed to be because the capacitance to ground differs for each stage due to the influence of the parasitic capacitance Cx, and the time constant expressed as the product of the resistance and capacitance differs.

[0039] FIG. 7 is a diagram showing an example of the voltage applied to each stage when a signal with a voltage of 1000 V is input to the attenuator 100 according to the comparative example.

[0040] In Fig. 7, in the steady-state region of several hundred Hz or less, the voltage applied to each stage is approximately the same value. Also, in the steady-state region of several hundred kHz or more, the voltage applied to each stage is a steady value, although the value is different.

[0041] In addition, in the transient region of several hundred Hz to several hundred kHz in Fig. 7, the voltage applied to each stage changes with frequency. Also, it differs depending on the stage at which the frequency at which the change starts. For example, the first stage starts to change at a lower frequency, the tenth stage starts to change at a higher frequency, and so on. The smaller i is, the lower the frequency at which the change starts.

[0042] Referring to FIG. 7, in a steady region of several hundred Hz or less, the voltage applied to each stage is a steady value, so the amplification factor of the attenuator 100 according to the comparative example is also a steady value. Also, in a transient region of several hundred Hz or more and several hundred kHz or less, the voltage of the first stage starts to increase, so the amplification factor of the attenuator 100 according to the comparative example starts to decrease. After that, the voltage of the fifth stage starts to decrease, and then the voltage of the tenth stage starts to decrease, so the amplification factor of the attenuator 100 according to the comparative example starts to increase. Also, in a steady region of several hundred kHz or more, the voltage applied to each stage is a steady value, although the value is different, so the amplification factor of the attenuator 100 according to the comparative example is also a steady value. As a result, the amplification factor of the attenuator 100 according to the comparative example has the characteristics shown in FIG. 3.

[0043] As described above, the attenuator 100 according to the comparative example does not exhibit the characteristics of a low-pass filter even if the parasitic capacitance Cx is present. However, the attenuator 100 according to the comparative example has a dip in the gain in a specific frequency range, such as around several tens of kHz. It is desirable that such a dip does not occur.

[0044] (Attenuator of the present disclosure) FIG. 8 is a diagram showing a schematic configuration of an attenuator 10 according to an embodiment.

[0045] The attenuator 10 according to one embodiment includes a resistor-capacitor unit 13, a load resistor RL, and a load capacitor CL. The load resistor RL and the load capacitor CL are connected in parallel.

[0046] The resistor-capacitor unit 13 includes resistors R1 to R10 and capacitors C1 to C10. The resistor R1 and the capacitor C1 are connected in parallel. Similarly, the resistors R2 to R10 are connected in parallel to the capacitors C2 to C10, respectively.

[0047] 1, resistor-capacitor unit 13 includes 10 resistors R1 to R10 and 10 capacitors C1 to C10, but this is just an example, and the numbers of resistors and capacitors included in resistor-capacitor unit 13 are not limited to this. Resistor-capacitor unit 13 may include n resistors R1 to Rn and n capacitors C1 to Cn, where n is an integer equal to or greater than 2. In this embodiment, a case where n=10 will be described as an example.

[0048] Hereinafter, the configuration in which resistor R1 and capacitor C1 are connected in parallel, the configuration in which resistor R2 and capacitor C2 are connected in parallel, ..., the configuration in which resistor R10 and capacitor C10 are connected in parallel may be referred to as "each stage" in the following description. Resistor-capacitor unit 13 is configured with each stage connected in series in a plurality of stages. In the example shown in Fig. 8, resistor-capacitor unit 13 is configured with each stage connected in series in ten stages.

[0049] The resistor-capacitor unit 13 is connected between the input terminal 11 and the output terminal 12. A load resistor RL and a load capacitor CL are connected between the output terminal 12 and ground.

[0050] In the attenuator 10 , a signal is input to an input terminal 11 and a signal is output from an output terminal 12 .

[0051] The resistance values ​​of resistors R1 to R10 and capacitance values ​​of capacitors C1 to C10 of resistor-capacitor unit 13 are adjusted so that the time constant of resistor Ri and capacitor Ci of each stage is equal to the time constant of the impedance to ground of each stage. Here, resistor Ri means the resistor of each stage up to the i-th stage. Capacitor Ci means the capacitor of each stage up to the i-th stage. Moreover, the impedance to ground means the impedance when looking from the node on the output terminal 12 side of each stage to the output terminal 12 side.

[0052] In the attenuator 100 according to the comparative example, the resistors R1 to R10 all have the same value, and the capacitors C1 to C10 also all have the same value. In contrast, in the attenuator 10 according to the embodiment, the resistance values ​​of the resistors R1 to R10 and the capacitance values ​​of the capacitors C1 to C10 of the resistor-capacitor unit 13 are adjusted so that the time constant of the resistor Ri and the capacitor Ci of each stage is equal to the time constant of the impedance to ground of each stage. In this respect, the attenuator 100 according to the comparative example is significantly different from the attenuator 10 according to the embodiment.

[0053] In the attenuator 10 according to the embodiment, the impedance to ground is calculated including the parasitic capacitance Cx.

[0054] The parasitic capacitance Cx occurs between the nodes at both ends of each stage and the ground, as shown in Fig. 8. The ground may be the ground of the substrate on which the attenuator 10 is configured, the housing of the device in which the attenuator 10 is housed, the earth, etc.

[0055] As described above, in the attenuator 10, the resistance values ​​of the resistors R1 to R10 and the capacitance values ​​of the capacitors C1 to C10 of the resistor-capacitor unit 13 are adjusted so that the time constant of the resistor Ri and capacitor Ci of each stage is equal to the time constant of the impedance to ground of each stage. In this case, the capacitance values ​​of the capacitors C1 to C10 may be adjusted, or the resistance values ​​of the resistors R1 to R10 may be adjusted. Below, the case where the capacitance values ​​of the capacitors C1 to C10 are adjusted and the case where the resistance values ​​of the resistors R1 to R10 are adjusted will be described respectively.

[0056] <Capacitance value adjustment> First, a case will be described where the capacitance values ​​of the capacitors C1 to C10 are adjusted. In this case, the resistance values ​​of the resistors R1 to R10 of the resistor-capacitor unit 13 are all the same. Also, the capacitance values ​​of the capacitors C1 to C10 of the resistor-capacitor unit 13 are all different values.

[0057] FIG. 8 shows the capacitance when looking at the output terminal 12 side from the node on the output terminal 12 side of each stage, C g1 ~C g10 Hereinafter, the term "capacitance to ground" will be used to refer to the capacitance when looking at the output terminal 12 side from the node on the output terminal 12 side of each stage.

[0058] The capacitance to ground is calculated based on the following formulas (1) and (2). Formula (1) is a formula for calculating the capacitance to ground of each stage up to the nth stage. n is the number of stages in resistor-capacitor unit 13. In the example shown in FIG. 8, n=10. Formula (2) is a formula for calculating the capacitance to ground of each stage other than the nth stage, i.e., each of the 1st to n-1th stages.

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[0059] The capacitance values ​​of the capacitors C1 to C10 of the resistor-capacitor unit 13 are calculated based on the following formulas (3) and (4). Formula (3) is a formula for calculating the capacitance value of the capacitor in each of the n-th stages. In the example shown in Fig. 8, n = 10. Formula (4) is a formula for calculating the capacitance value of the capacitor in each stage other than the n-th stage, i.e., the 1st to n-1th stages.

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[0060] An example of the capacitance values ​​of the capacitors C1 to C10 calculated using the above-mentioned formulas (1) to (4) is shown in Fig. 9. In the example shown in Fig. 9, the resistance values ​​of the resistors R1 to R10 are all 1.0 [MΩ]. The resistance value of the load resistor RL is 10.01 [kΩ]. The capacitance value of the load capacitor CL is 271.4 [pF]. The capacitance value of the parasitic capacitance Cx is 1.0 [pF].

[0061] Fig. 10 is a diagram showing an example of the impedance to ground of each stage when the capacitance values ​​of capacitors C1 to C10 of resistor-capacitor unit 13 are adjusted. Fig. 10 shows the impedance to ground of the first stage, the fifth stage, and the tenth stage.

[0062] Fig. 11 is a diagram showing an example of the impedance of each stage when the capacitance values ​​of capacitors C1 to C10 of resistor-capacitor unit 13 are adjusted. Fig. 11 shows the impedance of the first, fifth and tenth stages.

[0063] Comparing FIG. 10 and FIG. 11, it is found that the slope of the decrease in impedance to ground coincides with the slope of the decrease in impedance in the first, fifth, and tenth rows.

[0064] Fig. 12 is a diagram showing an example of voltages applied to each stage when the capacitance values ​​of capacitors C1 to C10 of resistor-capacitor unit 13 are adjusted. Fig. 12 shows voltages in the first stage, fifth stage, and tenth stage.

[0065] Referring to FIG. 12, the voltage is 100 V at all stages regardless of frequency.

[0066] FIG. 13 is a diagram showing the frequency characteristics of the attenuator 10 when the capacitance values ​​of the capacitors C1 to C10 of the resistor-capacitor unit 13 are adjusted.

[0067] 13, the amplification factor of the attenuator 10 is constant regardless of frequency, and there is no dip as seen in the frequency characteristic of the attenuator 100 according to the comparative example shown in FIG.

[0068] In this manner, by adjusting the capacitance values ​​of the capacitors C1 to C10 of the resistor-capacitor unit 13, the attenuator 10 according to one embodiment can improve the frequency characteristics.

[0069] <Resistance adjustment> Next, a case where the resistance values ​​of resistors R1 to R10 are adjusted will be described. In this case, the resistance values ​​of resistors R1 to R10 of resistor-capacitor unit 13 are all different values. Also, the capacitance values ​​of capacitors C1 to C10 of resistor-capacitor unit 13 are all the same value.

[0070] When adjusting the resistance values ​​of the resistors R1 to R10, the capacitance C to ground shown in FIG. 8 is adjusted in the same manner as when adjusting the capacitance values ​​of the capacitors C1 to C10. g1 ~C g10 is calculated based on the above formulas (1) and (2).

[0071] The resistance values ​​of resistors R1 to R10 of resistor-capacitor unit 13 are calculated based on the following formulas (5) and (6). Formula (5) is a formula for calculating the resistance value of a resistor in each n-th stage. In the example shown in Fig. 8, n = 10. Formula (6) is a formula for calculating the resistance value of resistors in each stage other than the n-th stage, i.e., the 1st to n-1th stages.

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[0072] An example of the resistance values ​​of resistors R1 to R10 calculated using the above-mentioned formulas (1), (2), (5), and (6) is shown in Fig. 14. In the example shown in Fig. 14, the capacitance values ​​of capacitors C1 to C10 are all 10 [pF]. The resistance value of load resistor RL is 10.01 [kΩ]. The capacitance value of load capacitor CL is 271.4 [pF]. The capacitance value of parasitic capacitance Cx is 1.0 [pF].

[0073] Fig. 15 is a diagram showing an example of the impedance to ground of each stage when the resistance values ​​of resistors R1 to R10 of resistor-capacitor unit 13 are adjusted. Fig. 15 shows the impedance to ground of the first, fifth and tenth stages.

[0074] Fig. 16 is a diagram showing an example of normalized impedance of each stage when adjusting the resistance values ​​of resistors R1 to R10 of resistor-capacitor unit 13. Fig. 16 shows the impedance of each of the first, fifth and tenth stages.

[0075] Comparing FIG. 15 and FIG. 16, it is found that the slope of the decrease in impedance to ground and the slope of the decrease in normalized impedance match in the first, fifth, and tenth rows, respectively.

[0076] Fig. 17 is a diagram showing an example of voltages applied to each stage when the resistance values ​​of resistors R1 to R10 of resistor-capacitor unit 13 are adjusted. Fig. 17 shows voltages in the first stage, fifth stage, and tenth stage.

[0077] Referring to FIG. 17, the voltage values ​​are different in the first, fifth, and tenth stages, but the voltage is constant regardless of the frequency in all of the first, fifth, and tenth stages.

[0078] When the resistance values ​​of the resistors R1 to R10 of the resistor-capacitor unit 13 are adjusted, the amplification factor of the attenuator 10 also has the frequency characteristics as shown in FIG.

[0079] 13, the amplification factor of the attenuator 10 is constant regardless of frequency, and there is no dip as seen in the frequency characteristic of the attenuator 100 according to the comparative example shown in FIG.

[0080] In this manner, by adjusting the resistance values ​​of the resistors R1 to R10 of the resistor-capacitor unit 13, the attenuator 10 according to one embodiment can improve the frequency characteristics.

[0081] According to the attenuator 10 of the embodiment as described above, it is possible to improve the frequency characteristic. More specifically, the resistance value of the resistor and the capacitance value of the capacitor of the resistor-capacitor unit 13 are adjusted so that the time constant of the resistor and the capacitor of each stage is equal to the time constant of the impedance when the output terminal 12 side is seen from the node on the output terminal 12 side of each stage. Furthermore, the impedance when the output terminal 12 side is seen from the node on the output terminal 12 side of each stage is calculated including the parasitic capacitance Cx. This allows the attenuator 10 to realize a frequency characteristic without a dip that occurs in the attenuator 100 of the comparative example. Therefore, according to the attenuator 10 of the embodiment, it is possible to improve the frequency characteristic.

[0082] <Example of using an attenuator> The attenuator 10 according to one embodiment can be used in a variety of applications.

[0083] For example, the attenuator 10 can be disposed in front of an amplifier in a signal input circuit that receives a high voltage, thereby forming a signal input circuit that can receive a high voltage and has excellent frequency characteristics.

[0084] For example, the attenuator 10 can be used in a probe that is used in combination with a measuring instrument, thereby forming a probe that is capable of inputting a high voltage and has excellent frequency characteristics.

[0085] For example, the attenuator 10 can be placed before each of the two inputs of a differential amplifier, thereby forming a differential circuit that can input a high voltage and has excellent frequency characteristics.

[0086] It is obvious to those skilled in the art that the present disclosure can be realized in other specific forms other than the above-described embodiments without departing from the spirit or essential characteristics thereof. Therefore, the above description is illustrative and not limiting. The scope of the disclosure is defined by the appended claims, not by the above description. Any modifications within the scope of the equivalents of all modifications are included therein.

[0087] For example, the arrangement and number of each component described above are not limited to the above description and the contents illustrated in the drawings. The arrangement and number of each component may be arbitrarily configured as long as the function can be realized.

[0088] For example, in the above-mentioned embodiment, the resistor-capacitor unit 13 of the attenuator 10 is configured with 10 stages connected in series. However, the number of stages of the resistor-capacitor unit 13 is not limited to 10, and may be any number of stages. The number of stages of the resistor-capacitor unit 13 may be appropriately adjusted according to the magnitude of the input voltage, the rating of the resistor, the rating of the capacitor, etc. For example, the number of stages of the resistor-capacitor unit 13 may be 5 stages or more and 20 stages or less. [Explanation of symbols]

[0089] 10 Attenuator 11 Input terminal 12 Output terminal 13 Resistor Capacitor Unit 100 Attenuator 200 Attenuator R1~R10 Resistors C1~C10 Capacitors RL load resistance CL Load Capacitor Cx parasitic capacitance

Claims

1. A resistor-capacitor unit in which each stage is composed of a parallel connection of a resistor and a capacitor and is connected in series in multiple stages; A load resistor and a load capacitor connected in parallel; Equipped with The resistor-capacitor unit is connected between an input terminal and an output terminal, the load resistor and the load capacitor are connected between the output terminal and ground; a resistance value of the resistor and a capacitance value of the capacitor of the resistor-capacitor unit are adjusted so that a time constant of the resistor and the capacitor of each stage is equal to a time constant of an impedance when the output terminal side is viewed from a node on the output terminal side of each stage, An attenuator, wherein the impedance is calculated including parasitic capacitance between both ends of each stage and the ground.

2. 2. The attenuator of claim 1, The resistors in the resistor-capacitor unit all have the same resistance value, An attenuator, wherein the capacitance values ​​of the capacitors of the resistor-capacitor unit are all different.

3. 3. The attenuator of claim 2, An attenuator, wherein a capacitance value of a capacitance when looking at the output terminal side from a node on the output terminal side of each stage is calculated based on the following equations (1) and (2). [0010] In the formula (1), C ｇｎ is the capacitance value of the capacitance when looking at the output terminal from the node on the output terminal side of each of the nth stages, n is the number of stages in the resistor-capacitor unit, CL is the capacitance value of the load capacitor, and Cx is the capacitance value of the parasitic capacitance. [0025] In the formula (2), C ｇｉ is the capacitance value of the capacitance when looking at the output terminal side from the node on the output terminal side of each stage of the i-th stage, and C ｉ＋１ is the capacitance value of the capacitor in each stage of the i+1th stage, and C ｇｉ＋１ is the capacitance value of the capacitance when looking at the output terminal side from the node on the output terminal side of each stage of the (i+1)th stage.

4. 4. The attenuator of claim 3, An attenuator, wherein the capacitance value of the capacitor of the resistor-capacitor unit is calculated based on the following equations (3) and (4). [0030] In the formula (3), C ｎ is the capacitance value of the capacitor of each of the n-th stages, RL is the resistance value of the load resistor, and R ｎ is the resistance value of the resistor in each of the n-th stages. [0045] However, in formula (4), C ｉ is the capacitance value of the capacitor in the i-th stage, and R ｉ is the resistance value of the resistor in the i-th stage.

5. 2. The attenuator of claim 1, the resistors in the resistor-capacitor unit all have different resistance values; An attenuator, wherein the capacitance values ​​of the capacitors in the resistor-capacitor unit are all the same.

6. 6. The attenuator of claim 5, An attenuator, wherein a capacitance value of a capacitance when looking at the output terminal side from a node on the output terminal side of each stage is calculated based on the following equations (5) and (6). [0050] In the formula (5), C ｇｎ is the capacitance value of the capacitance when looking at the output terminal from the node on the output terminal side of each of the nth stages, n is the number of stages in the resistor-capacitor unit, CL is the capacitance value of the load capacitor, and Cx is the capacitance value of the parasitic capacitance. [006] In the formula (6), C ｇｉ is the capacitance value of the capacitance when looking at the output terminal side from the node on the output terminal side of each stage of the i-th stage, and C ｉ＋１ is the capacitance value of the capacitor in each stage of the i+1th stage, and C ｇｉ＋１ is the capacitance value of the capacitance when looking at the output terminal side from the node on the output terminal side of each stage of the (i+1)th stage.

7. 7. The attenuator of claim 6, An attenuator, wherein the resistance value of the resistor of the resistor-capacitor unit is calculated based on the following equations (7) and (8). [0070] In the formula (7), R ｎ is the resistance value of the resistor in each of the n-th stages, RL is the resistance value of the load resistor, and C ｎ is the capacitance value of the capacitor in each of the n-th stages. [0080] In the formula (8), R ｉ is the resistance value of the resistor in the i-th stage, and C ｉ is the capacitance value of the capacitor in the i-th stage.

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