Measuring device and standard resistor

Abstract

To enable errors of measurement by a measuring device to be easily known.SOLUTION: A measuring device 100 is characterized by comprising: a data processing control circuit 4 that measures impedance between first internal terminals hci, hpi and second internal terminals lci, lpi on the basis of the voltage and current between the first internal terminals hci, hpi and the second internal terminals lci, lpi when a voltage or a current is applied between the first internal terminals hci, hpi and the second internal terminals lci, lpi; a reference circuit 8 that has prescribed impedance; and a switch unit 5 that switches the connection destination of the first internal terminals hci, hpi between first external terminals HC, HP and one terminal of the reference circuit 8, and switches the connection destination of the second internal terminals lci, lpi between second external terminals LC, LP and the other terminal of the reference circuit 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measuring device and a standard resistor, and more particularly to a measuring device for measuring electrical characteristics of an object to be measured. [Background technology]

[0002] BACKGROUND ART Measuring devices such as LCR meters, resistance meters, and battery testers that measure electrical characteristics such as impedance of a device under test (hereinafter also referred to as a "DUT") are known (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-76600 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned measurement device is configured to include various internal circuits such as a generation circuit that generates a voltage or current to be applied to the DUT, a voltage detection circuit that detects the voltage generated in the DUT, and a current detection circuit that detects the current flowing through the DUT. The characteristics of these internal circuits are affected by the characteristics of the electronic components that make up the circuits, such as a reference voltage source, reference resistor, gain setting resistor, transistor, and capacitor.

[0005] It is generally known that the characteristics of electronic components change with temperature and aging. If the characteristics of electronic components change due to temperature and aging, the characteristics of various internal circuits that make up the measurement device may change, which may result in an error between the true value of the DUT impedance and the DUT impedance measurement result obtained by the measurement device.

[0006] To achieve higher accuracy in measurements, it is important to know the measurement error of a measuring device. However, many conventional measuring devices do not have a function that allows easy detection of the measurement error of the measuring device itself.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to make it possible to easily know the error in measurement by a measurement device. [Means for solving the problem]

[0008] A measuring device according to a representative embodiment of the present invention is characterized by comprising: a first external terminal for connecting one terminal of a test object; a second external terminal for connecting the other terminal of the test object; a first internal terminal and a second internal terminal; a generating circuit for applying a voltage or current between the first internal terminal and the second internal terminal; a voltage detection circuit for detecting the voltage between the first internal terminal and the second internal terminal; a data processing control circuit for measuring the impedance between the first internal terminal and the second internal terminal based on the voltage detected by the voltage detection circuit and the current flowing between the first internal terminal and the second internal terminal; a reference circuit having two terminals and a predetermined impedance; and a switch unit for switching the connection destination of the first internal terminal between the first external terminal and one terminal of the reference circuit and for switching the connection destination of the second internal terminal between the second external terminal and the other terminal of the reference circuit. [Effects of the Invention]

[0009] According to the measuring device of the present invention, the error in the measurement by the measuring device can be easily known. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a configuration of a measurement device according to a first embodiment. [Figure 2A] 3 is a diagram illustrating an example of connections between switches constituting a switch unit; FIG. [Figure 2B]3 is a diagram illustrating an example of connections between switches constituting a switch unit; FIG. [Figure 3] FIG. 2 is a diagram illustrating a configuration of a data processing control circuit according to the first embodiment. [Figure 4] 4 is a flowchart showing the flow of impedance measurement by the measurement device according to the first embodiment. [Figure 5] FIG. 10 is a diagram showing the configuration of a measurement device according to a second embodiment. [Figure 6] FIG. 10 is a diagram illustrating an example of a reference circuit according to a second embodiment. [Figure 7] FIG. 10 is a diagram illustrating a configuration of a data processing control circuit according to a second embodiment. [Figure 8] 10 is a flowchart showing the flow of impedance measurement by the measurement device according to the second embodiment. [Figure 9] FIG. 10 is a diagram showing the configuration of a measurement device according to a third embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of a reference circuit according to a third embodiment. [Figure 11] FIG. 10 is a diagram illustrating a configuration of a data processing control circuit according to a third embodiment. [Figure 12] 10 is a flowchart showing the flow of impedance measurement by the measurement device according to the third embodiment. [Figure 13] FIG. 1 is a diagram showing the configuration of a measurement device capable of measuring impedance by the two-terminal method. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1. Overview of the embodiment First, a typical embodiment of the invention disclosed in this application will be outlined. In the following description, for example, reference numerals in the drawings corresponding to components of the invention are written in parentheses.

[0012] [1] A measuring device (100, 100A, 100B, 100C) according to a representative embodiment of the present invention includes first external terminals (HC, HP, H) for connecting one terminal of a test object (200) and second external terminals (LC, LP, L) for connecting the other terminal of the test object, first internal terminals (hci, hpi, hi) and second internal terminals (lci, lpi, li), a generating circuit (1) for applying a voltage or current between the first internal terminal and the second internal terminal, a voltage detection circuit (3) for detecting a voltage between the first internal terminal and the second internal terminal, and a voltage detection circuit (4) for detecting a voltage between the first internal terminal and the second internal terminal. a data processing control circuit (4, 4A, 4B) that measures the impedance between the first internal terminal and the second internal terminal based on the output voltage and the current flowing between the first internal terminal and the second internal terminal; a reference circuit (8, 8A, 8B, 8C) that has two terminals and a predetermined impedance; and a switch unit (5, 5C) that switches the connection destination of the first internal terminal between the first external terminal and one terminal of the reference circuit, and switches the connection destination of the second internal terminal between the second external terminal and the other terminal of the reference circuit.

[0013] [2] In the measuring device described in [1] above, the data processing control circuit may correct a measurement result of the impedance between the first internal terminal and the second internal terminal when the first external terminal and the first internal terminal are connected by the switch unit and the second external terminal and the second internal terminal are connected by the switch unit under the second condition (see FIG. 2B) based on an error between a measurement result of the impedance of the reference circuit when, under a first condition, the switch unit connects one terminal of the reference circuit to the first internal terminal and the other terminal of the reference circuit to the second internal terminal (see FIG. 2A) and a measurement result of the impedance of the reference circuit when, under a second condition different from the first condition, the switch unit connects one terminal of the reference circuit to the first internal terminal and the other terminal of the reference circuit to the second internal terminal (see FIG. 2A).

[0014] [3] In the measuring device (100, 100A, 100B, 100C) described in [2] above, the data processing control circuit (4, 4A, 4B) may correct the value of the resistance component of the impedance of the test object measured under the second condition based on the error between the value (Rr1) of the resistance component of the impedance of the reference circuit (8, 8A, 8B, 8C) measured under the first condition and the value (Rr2) of the resistance component of the impedance of the reference circuit measured under the second condition.

[0015] [4] In the measuring device described in [3] above, the data processing control circuit may calculate a first correction coefficient (Gfix) based on the ratio between the value (Rr1) of the resistance component of the impedance of the reference circuit measured under the first condition and the value (Rr2) of the resistance component of the impedance of the reference circuit measured under the second condition, and may use the first correction coefficient to correct the value of the resistance component of the impedance of the test object measured under the second condition.

[0016] [5] In the measuring device (100A, 100B, 100C) described in [2] above, the data processing control circuit (4A, 4B) may correct the value of the phase angle of the impedance of the test object measured under the second condition based on the error between the value of the phase angle of the impedance of the reference circuit measured under the first condition (θr1) and the value of the phase angle of the impedance of the reference circuit measured under the second condition (θr2).

[0017] [6] In the measuring device described in [5] above, the data processing control circuit may calculate a second correction coefficient (θfix) based on the difference between the phase angle value (θr1) of the impedance of the reference circuit measured under the first condition and the phase angle value (θr2) of the impedance of the reference circuit measured under the second condition, and may use the second correction coefficient to correct the phase angle value of the impedance of the test object measured under the second condition.

[0018] [7] In the measuring device (100, 100A, 100B, 100C) according to any one of [2] to [6] above, the data processing control circuit includes an instruction receiving unit (40, 40B) that receives an instruction to the measuring device, a memory unit (46, 46A, 46B) that stores an impedance value (Rr1, θr1) of the reference circuit measured under the first condition and correction coefficient information (Gfix, θfix) for correcting the impedance value of the device under test measured under the second condition, a switch control unit (41) that controls the switch unit, an impedance calculation unit (43, 43A, 43B) that calculates the impedance value between the first internal terminal and the second internal terminal, a correction unit (44, 44A, 44B) that corrects the impedance value calculated by the impedance calculation unit based on the correction coefficient information, and a measurement unit (44, 44A, 44B) that outputs the impedance value corrected by the correction unit as a measurement result. The reference circuit may further include a result output unit (45) and a correction coefficient update unit (42, 42A, 42B) that updates the correction coefficient information, wherein when the instruction reception unit receives a predetermined instruction, the switch unit connects one terminal of the reference circuit to the first internal terminal and connects the other terminal of the reference circuit to the second internal terminal, the impedance calculation unit calculates an impedance value between the first internal terminal and the second internal terminal and stores the calculated impedance value in the memory unit as an impedance value (Rr2, θr2) of the reference circuit measured under the second condition, and the correction coefficient update unit updates the correction coefficient information (Gfix, θfix) based on the impedance value (Rr1, θr1) of the reference circuit measured under the first condition and the impedance value (Rr2, θr2) of the reference circuit measured under the second condition, which are stored in the memory unit.

[0019] [8] In the measurement device according to any one of [1] to [7] above, the reference circuit (8, 8A, 8C) may include a resistor (Rref).

[0020] [9] In the measuring device (100B) described in [1] above, the first internal terminal includes a high-side internal application terminal (hci) to which a voltage or current is applied from the generating circuit and a high-side internal detection terminal (hpi) connected to the voltage detection circuit, the second internal terminal includes a low-side internal application terminal (lci) to which a voltage or current is applied from the generating circuit and a low-side internal detection terminal (lpi) connected to the voltage detection circuit, and the first external terminal includes a high-side external application terminal (HC) and a high-side external detection terminal (HP). , and the second external terminal includes a low-side external application terminal (LC) and a low-side external detection terminal (LP), and the reference circuit (8B) includes a high-side input terminal (hcr) and a high-side output terminal (hpr) as one terminal of the reference circuit, a low-side input terminal (lcr) and a low-side output terminal (lpr) as the other terminal of the reference circuit, a first resistor (Rm) connected between the high-side input terminal and the low-side input terminal, and a resistor (Rm) connected between the high-side input terminal and the low-side input terminal and a selection circuit (81) that receives as input a voltage between the high-side input terminal and the low-side input terminal and a plurality of voltages divided by the plurality of second resistors, selects one of the input voltages, and outputs the selected voltage between the high-side output terminal and the low-side output terminal, wherein the switch unit may switch a connection destination of the high-side internal application terminal (hci) between the high-side external application terminal (HC) and the high-side input terminal (hcr) of the reference circuit, switch a connection destination of the low-side internal application terminal (lci) between the low-side external application terminal (LC) and the low-side input terminal (lcr) of the reference circuit, switch a connection destination of the high-side internal detection terminal (hpi) between the high-side external detection terminal (HP) and the high-side output terminal (hpr) of the reference circuit, and switch a connection destination of the low-side internal detection terminal (lpi) between the low-side external detection terminal (LP) and the low-side output terminal (lpr) of the reference circuit.

[0021]

[10] In the measuring device (100B) described in [9] above, a selection signal (Ss) specifying a measurement range may be input to the selection circuit, and the selection circuit may select and output a voltage from the input voltages that corresponds to the measurement range specified by the selection signal.

[0022]

[11] In the measuring device (100B) described in [9] or

[10] above, the plurality of second resistors (Ra1 to Ran) may be a network resistor.

[0023]

[12] A standard resistor (8B) according to a representative embodiment of the present invention includes a high-side input terminal (hcr) and a high-side output terminal (hpr), a low-side input terminal (lcr) and a low-side output terminal (lpr), a first resistor (Rm) connected between the high-side input terminal and the low-side input terminal, a plurality of second resistors (Ra1 to Ran) connected in series between the high-side input terminal and the low-side input terminal, and a selection circuit (81) that receives as input a voltage between the high-side input terminal and the low-side input terminal and a plurality of voltages divided by the plurality of second resistors, selects one of the input voltages, and outputs the selected voltage between the high-side output terminal and the low-side output terminal.

[0024] 2. Specific examples of embodiments Specific examples of embodiments of the present invention will be described below with reference to the drawings. In the following description, components common to each embodiment will be given the same reference numerals, and repeated description will be omitted. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from the actual situation. The drawings may also include portions with different dimensional relationships and ratios.

[0025] First Embodiment FIG. 1 is a diagram showing the configuration of a measurement device 100 according to the first embodiment.

[0026] 1 is a device for measuring the electrical characteristics of a DUT. Examples of the measuring device 100 include a resistance meter, an LCR meter, and a capacitance meter that can measure impedance using a two-terminal method or a four-terminal method, and a battery tester that measures battery characteristics. Note that the measuring device 100 is not limited to the above examples as long as it is a device that can measure the electrical characteristics such as the impedance of a DUT.

[0027] In addition to the function of measuring the electrical characteristics of the DUT, the measurement apparatus 100 also has the function of correcting measurement errors caused by changes in the circuit characteristics within the measurement apparatus 100 due to temperature or aging.

[0028] The measuring device 100 has components for realizing the above-mentioned functions, such as an external terminal, an internal terminal, a generating circuit 1, a current detection circuit 2, a voltage detection circuit 3, a data processing control circuit 4, a switch unit 5, an output unit 6, an operation unit 7, and a reference circuit (REF) 8.

[0029] The external terminals are terminals for connecting a DUT. Measurement apparatus 100 has the following external terminals: a high-side external application terminal HC, a high-side external detection terminal HP, a low-side external detection terminal LP, and a low-side external application terminal LC. For example, when measuring the impedance of a DUT using measurement apparatus 100, one terminal of the DUT is connected to high-side external application terminal HC and high-side external detection terminal HP, and the other terminal of the DUT is connected to low-side external detection terminal LP and low-side external application terminal LC. In the following description, the high-side external application terminal HC, the high-side external detection terminal HP, the low-side external detection terminal LP, and the low-side external application terminal LC may be simply referred to as "external terminals HC, HP, LC, LP."

[0030] The internal terminals are terminals connected to circuits (generating circuit 1, current detecting circuit 2, and voltage detecting circuit 3) within the measuring device 100. The measuring device 100 has, as its internal terminals, a high-side internal application terminal hci, a high-side internal detection terminal hpi, a low-side internal application terminal lci, and a low-side internal detection terminal lpi.

[0031] The high-side internal application terminal hci is connected to the positive output terminal of the generating circuit 1, and the low-side internal application terminal lci is connected to the negative output terminal of the generating circuit 1 via the current detecting circuit 2. The high-side internal detection terminal hpi is connected to the positive input terminal of the voltage detecting circuit 3, and the low-side internal detection terminal lpi is connected to the negative input terminal of the voltage detecting circuit 3.

[0032] In the following description, the high-side internal application terminal hci, the high-side internal detection terminal hpi, the low-side internal application terminal lci, and the low-side internal detection terminal lpi may be simply referred to as "internal terminals hci, hpi, lci, lpi."

[0033] Although details will be described later, the internal terminals hci, lci, hpi, and lpi are connectable by the switch section 5 to the external terminals HC, LC, HP, and LP or to the terminals of the reference circuit 8.

[0034] The generating circuit 1 is a circuit that generates a voltage or current to be applied to a measurement object in order to measure impedance. The generating circuit 1 applies a voltage or current between internal terminals hci and lci. The generating circuit 1 is, for example, a constant current generating circuit that generates a constant current, or a voltage generating circuit that generates a voltage. In the first embodiment, the generating circuit 1 is described as a constant current generating circuit, as an example.

[0035] The generating circuit 1 generates a constant current signal in response to a signal Sb from the data processing control circuit 4, and outputs the signal from a positive output terminal and a negative output terminal. For example, the positive output terminal of the generating circuit 1 is connected to the internal terminal hci, and the negative output terminal of the generating circuit 1 is connected to the internal terminal lci via the current detection circuit 2.

[0036] The constant current signal output from the generating circuit 1 may be an AC signal or a DC signal, and may be changed depending on the application of the measuring device 100, for example.

[0037] The current detection circuit 2 is a circuit that detects the current flowing between the internal terminals hci and lci. For example, the current detection circuit 2 is connected in series between the positive output terminal of the generator circuit 1 and the internal terminal hci, or between the negative output terminal of the generator circuit 1 and the internal terminal lci. Figure 1 shows, as an example, a case where the current detection circuit 2 is connected in series between the negative output terminal of the generator circuit 1 and the internal terminal lci.

[0038] The current detection circuit 2 is configured to include, for example, a resistor connected in series between the negative output terminal of the generating circuit 1 and the internal terminal lci, and an operational amplifier that amplifies the voltage across the resistor and outputs it as a current signal.

[0039] The voltage detection circuit 3 has a positive input terminal and a negative input terminal, and detects the voltage between the positive input terminal and the negative input terminal. The positive input terminal of the voltage detection circuit 3 is connected to the internal terminal hpi, and the negative input terminal of the voltage detection circuit 3 is connected to the internal terminal lpi. The voltage detection circuit 3 detects and outputs the voltage between the internal terminals hpi and lpi. The voltage detection circuit 3 has, for example, an operational amplifier, and amplifies the detected voltage between the external terminals HP and LP using the operational amplifier and outputs the amplified voltage as a voltage signal.

[0040] The operation unit 7 is an input interface that allows the user to operate the measurement apparatus 100. Examples of the operation unit 7 include various buttons and a touch panel. For example, by operating the operation unit 7, the user can set various measurement conditions for measuring the DUT in the measurement apparatus 100 and instruct the measurement apparatus 100 to start and stop the measurement. Furthermore, by operating the operation unit 7, the user can instruct the measurement apparatus 100 to update a correction coefficient, which will be described later. The operation unit 7 generates a signal Sd that instructs the measurement apparatus 100 to execute processing in accordance with various commands input by the user operating the operation unit 7, and provides the signal Sd to each functional unit.

[0041] The output unit 6 is a device that outputs various information such as the measurement conditions and measurement results of the measurement device 100. The output unit 6 is, for example, a display device such as an LCD (Liquid Crystal Display) or an organic EL. For example, when a user inputs an instruction to measure the impedance of the DUT into the operation unit 7, the output unit 6 displays information such as the measurement results of the impedance of the DUT calculated by the data processing control circuit 4 on the screen.

[0042] The output unit 6 may be a display device equipped with a touch panel that realizes some of the functions of the operation unit 7. The output unit 6 may also include a communication circuit or the like that outputs data such as measurement results to the outside via a wired or wireless connection.

[0043] Here, the communication circuit may have not only a function of transmitting data to the outside but also a function of receiving data from the outside. For example, when the communication circuit receives various commands such as to start or stop measurement, update correction coefficients, etc. output from an external device (for example, an information processing device such as a PC), it may generate a signal Sd instructing the execution of processing according to the various received commands, and provide the signal Sd to each functional unit, similar to the operation unit 7. Furthermore, the output unit 6 may include a speaker or the like that notifies the start or end of measurement by sound.

[0044] The data processing control circuit 4 is a circuit that comprehensively controls each functional unit within the measuring device 100. Examples of the data processing control circuit 4 include a program processing device such as an MCU (Micro Controller Unit) or FPGA (Field-Programmable Gate Array) that has a processor such as a CPU, a storage device such as a ROM, RAM, or flash memory, and various peripheral circuits such as a timer and an A / D conversion circuit.

[0045] The data processing control circuit 4 controls each functional unit in the measurement device 100 in response to a signal Sd from the operation unit 7, thereby calculating, for example, the measured impedance value of the DUT 200 or the reference circuit 8, updating a correction coefficient (to be described later), and correcting the measured value using the correction coefficient. Details of the data processing control circuit 4 will be described later.

[0046] The reference circuit 8 is a circuit capable of measuring impedance by connecting it to the generation circuit 1 and the voltage detection circuit 3, just like the DUT. The reference circuit 8 can be used to calculate and correct errors in measurements made by the measurement apparatus 100. The reference circuit 8 includes, for example, a high-side terminal and a low-side terminal. For example, the reference circuit 8 has a high-side input terminal hcr and a high-side output terminal hpr as high-side terminals, and a low-side input terminal lcr and a low-side output terminal lpr as low-side terminals.

[0047] In the following description, the high-side input terminal hcr, high-side output terminal hpr, low-side input terminal lcr, and low-side output terminal lpr of the reference circuit 8 may be simply referred to as "terminals hcr, hpr, lcr, lpr."

[0048] The reference circuit 8 includes, for example, a resistor. In the first embodiment, as an example, the reference circuit 8 is realized by a resistor having a predetermined resistance value, and the resistor is referred to as a "reference resistor Rref."

[0049] One terminal of the reference resistor Rref is connected to the high-side input terminal hcr and the high-side output terminal hpr, and the other terminal of the reference resistor Rref is connected to the low-side input terminal lcr and the low-side output terminal lpr.

[0050] The reference resistor Rref is preferably a resistor with high accuracy and reliability. For example, it is preferable to use a precision resistor with a temperature coefficient of resistance of ±5 ppm / °C or less and a long-term stability (aging) of resistance of ±100 ppm / year or less as the reference resistor Rref. Note that the above values are merely examples and can be changed as appropriate depending on the specifications required for the measuring device 100. The resistance value of the reference resistor Rref can be set as appropriate depending on the measurable range of impedance by the measuring device 100.

[0051] The switch unit 5 is a functional unit that switches the connection destinations of the internal terminals hci, hpi, lci, and lpi. Each of the switches 51 to 54 constituting the switch unit 5 is configured by, for example, a double-throw switch element. Examples of the switch element include components that can switch the connection destination in response to an electric signal, such as a semiconductor switch (for example, a transistor) or a relay (for example, a mechanical relay).

[0052] The switch unit 5 switches the connection destination of the internal terminals hci, hpi between the external terminal HC and one of the terminals hcr, hpr of the reference circuit 8, and switches the connection destination of the internal terminals lci, lpi between the external terminal LC and the other of the terminals lcr, lpr of the reference circuit 8. The switch unit 5 switches the connection destination of the internal terminals hci, hpi, lci, lpi in response to a signal Sc from the data processing control circuit 4.

[0053] 2A and 2B are diagrams showing examples of connections between the switches 51 to 54 that make up the switch section 5. FIG.

[0054] Figure 2A shows a case where the internal terminals hci, hpi, lci, and lpi are connected to the reference circuit 8 when measuring the impedance of the reference circuit 8, and Figure 2B shows a case where the internal terminals hci, hpi, lci, and lpi are connected to the external terminals HC, HP, LC, and LP when measuring the impedance of the DUT 200.

[0055] 2A in response to the signal Sc from the data processing control circuit 4. That is, the switch 51 connects the internal terminal hci to the terminal hcr of the reference circuit 8, the switch 52 connects the internal terminal hpi to the terminal hpr of the reference circuit 8, the switch 53 connects the internal terminal lci to the terminal lcr of the reference circuit 8, and the switch 54 connects the internal terminal lpi to the terminal lpr of the reference circuit 8. As a result, the internal terminals hci, hpi, lci, and lpi are connected to the reference resistor Rref of the reference circuit 8.

[0056] 2B in response to the signal Sc from the data processing control circuit 4. That is, the switch 51 connects the internal terminal hci to the external terminal HC, the switch 52 connects the internal terminal hpi to the external terminal HP, the switch 53 connects the internal terminal lci to the external terminal LC, and the switch 54 connects the internal terminal lpi to the external terminal LP. As a result, the internal terminals hci, hpi, lci, and lpi are connected to the DUT 200.

[0057] Here, the data processing control circuit 4 will be described in detail.

[0058] The data processing control circuit 4 measures the value of the impedance between the internal terminals hpi and lpi based on the voltage detected by the voltage detection circuit 3 and the current detected by the current detection circuit 2.

[0059] Specifically, the data processing control circuit 4 acquires a measurement result of the impedance of the reference circuit 8 under a first condition when the switch unit 5 connects one terminal of the reference circuit 8, hcr, hpr, to the internal terminals hci, hpi, and also connects the other terminal of the reference circuit, lcr, lpr, to the internal terminals lci, lpi (see FIG. 2A). Also, under a second condition different from the first condition, the data processing control circuit 4 acquires a measurement result of the impedance of the reference circuit 8 under a second condition when the switch unit 5 connects one terminal of the reference circuit 8, hcr, hpr, to the internal terminals hci, hpi, and also connects the other terminal of the reference circuit 8, lcr, lpr, to the internal terminals lci, lpi (see FIG. 2A). Furthermore, under the second condition, the data processing control circuit 4 acquires the measurement results of the impedance between the internal terminals hci, hpi and the internal terminals lci, lpi when the external terminals HC, HP are connected to the internal terminals hci, hpi by the switch unit 5 and the external terminals LC, LP are connected to the internal terminals lci, lpi (see Figure 2B).

[0060] The data processing control circuit 4 corrects the measurement result of the impedance between the internal terminals hci, hpi and the internal terminals lci, lpi when the external terminals HC, HP are connected to the internal terminals hci, hpi and the external terminals LC, LP are connected to the internal terminals lci, lpi under the second condition, based on the error between the measurement result of the impedance of the reference circuit 8 under the first condition and the measurement result of the impedance of the reference circuit 8 under the second condition.

[0061] More specifically, the data processing control circuit 4 corrects the value of the resistance component of the impedance of the DUT 200 measured under the second condition based on the error between the value Rr1 of the resistance component of the impedance of the reference circuit 8 measured under the first condition and the value Rr2 of the resistance component of the impedance of the reference circuit 8 measured under the second condition.

[0062] For example, the data processing control circuit 4 calculates a correction coefficient for correcting the measured (calculated) impedance value of the DUT 200. Specifically, the data processing control circuit 4 calculates a first correction coefficient Gfix based on the ratio between the value Rr1 of the resistance component of the impedance of the reference circuit 8 measured under the first condition and the value Rr2 of the resistance component of the impedance of the reference circuit 8 measured under the second condition.

[0063] The data processing control circuit 4 uses the calculated first correction coefficient Gfix to correct the measurement result of the resistance component of the impedance of the DUT 200 measured under the second condition. For example, the data processing control circuit 4 corrects the value R of the resistance component of the impedance of the DUT 200 measured under the second condition by multiplying the value R of the resistance component of the impedance of the DUT 200 measured under the second condition by the first correction coefficient Gfix.

[0064] FIG. 3 is a diagram showing the configuration of the data processing control circuit 4 according to the first embodiment.

[0065] 3, the data processing control circuit 4 has, as functional blocks for realizing the above-mentioned functions, for example, an instruction receiving unit 40, a switch control unit 41, a correction coefficient updating unit 42, an impedance calculating unit 43, a correction unit 44, a measurement result output unit 45, and a storage unit 46. These functional blocks are realized, for example, by a processor in a program processing unit (MCU) serving as the data processing control circuit 4 executing various arithmetic processes in accordance with programs stored in a storage device and controlling peripheral circuits. Note that some or all of the above functional blocks may be realized by dedicated logic circuits.

[0066] The instruction receiving unit 40 is a functional unit that receives instructions to the measurement device 100. The instruction receiving unit 40 receives a signal Sd from the operation unit 7, and instructs other functional units, such as a lock, to execute processing in accordance with the signal Sd.

[0067] For example, when a user operates the operation unit 7 to instruct the execution of measurement of the impedance of DUT200, the instruction receiving unit 40 instructs the switch control unit 41, the correction coefficient update unit 42, the impedance calculation unit 43, etc. to execute processing to measure the impedance of DUT200 in response to the signal Sd output from the operation unit 7.

[0068] Furthermore, for example, a user may issue an instruction to update the correction coefficient by operating the operation unit 7. In this case, the instruction receiving unit 40 instructs the switch control unit 41, the correction coefficient updating unit 42, the impedance calculation unit 43, etc. to execute processing to update the correction coefficient.

[0069] Furthermore, for example, the user may operate the operation unit 7 to issue an instruction to measure the impedance of the reference circuit 8 (reference resistor Rref). In this case, the instruction receiving unit 40 instructs the switch control unit 41, the correction coefficient updating unit 42, the impedance calculating unit 43, etc. to execute processing to measure the impedance of the reference circuit 8 in response to the signal Sd output from the operation unit 7. In this case, information on the measurement results of the impedance of the reference circuit 8 may be displayed on a screen by the output unit 6 or output as measurement data to an external device. Furthermore, the output unit 6 may output (display) not only information on the latest measurement results of the impedance of the reference circuit 8, but also information on measurement results of the impedance of the reference circuit 8 measured in the past (measurement results of the reference circuit 8 under first conditions, which will be described later).

[0070] The storage unit 46 is a functional unit that stores the calculation formulas, various parameters, measurement results, correction coefficients, etc., required for measuring the electrical characteristics of the DUT and calculating the correction coefficients.

[0071] For example, the storage unit 46 stores a reference measurement result (first condition) 401 including a value Rr1 of the reference resistance Rref measured under a first condition, a reference measurement result (second condition) 402 including a value Rr2 of the reference resistance Rref measured under a second condition, correction coefficient information 403 including a first correction coefficient Gfix, a DUT measurement result (second condition) 404 including a value R of the resistance component of the DUT 200 measured under the second condition, and a corrected DUT 200 measurement result 405 including a value Rf obtained by correcting the value R of the resistance component of the DUT 200 measured under the second condition, which will be described later. The storage unit 46 also stores various arithmetic expressions required for impedance measurement, such as an arithmetic expression for calculating an impedance value, an arithmetic expression for calculating a correction coefficient, and an arithmetic expression for correcting the measurement result.

[0072] The switch control unit 41 is a functional unit for controlling the switch unit 5. The switch control unit 41 controls the switch unit 5 in response to an instruction from the instruction receiving unit 40, for example, to switch the connection destinations of the internal terminals hci, hpi, lci, and lpi.

[0073] The impedance calculation unit 43 is a functional unit that calculates the value of the impedance between the internal terminals hpi and lpi. The impedance calculation unit 43 calculates the value of the impedance between the internal terminals hpi and lpi based on the voltage value V detected by the voltage detection circuit 3 and the current value I detected by the current detection circuit 2.

[0074] Specifically, as described above, the calculation formula for calculating the value of the resistance component of the impedance is stored in the memory unit 46, and the impedance calculation unit 43 calculates the value of the resistance component of the impedance using the calculation formula stored in the memory unit 46.

[0075] For example, when DUT200 is connected to internal terminals hci, hpi, lci, and lpi, and current is applied to DUT200 from generating circuit 1, the voltage detected by voltage detection circuit 3 is V and the current detected by current detection circuit 2 is I, the impedance calculation unit 43 calculates the value R of the resistance component of the impedance of DUT200 using the arithmetic formula "R=V / I" stored in memory unit 46, and stores it in memory unit 46 as DUT measurement result 404.

[0076] The calculation formula for calculating the impedance is not limited to the above example, and can be changed as appropriate depending on the specifications required for the measurement device 100. For example, when performing an initial adjustment (described later), a correction coefficient obtained by the initial adjustment may be included in the above formula.

[0077] The correction coefficient update unit 42 is a functional unit that calculates correction coefficients and updates the correction coefficients stored in the storage unit 46 . The correction coefficient update unit 42 calculates a first correction coefficient Gfix based on the ratio between the value Rr1 of the resistance component of the impedance of the reference circuit 8 measured under the first condition and the value Rr2 of the resistance component of the impedance of the reference circuit 8 measured under the second condition, and stores the calculated first correction coefficient Gfix as correction coefficient information 403 in the storage unit 46. For example, every time the correction coefficient update unit 42 calculates the first correction coefficient Gfix, it updates the correction coefficient information 403 (first correction coefficient Gfix) stored in the storage unit 46 to the latest value.

[0078] The method for calculating the first correction coefficient Gfix will be described in detail below. For example, when the measurement device 100 is manufactured or shipped, a standard resistor (with the theoretical resistance value = Rr) having a high accuracy is connected to the measurement device 100 as the DUT 200, and the measurement device 100 measures the resistance value of the standard resistor. Then, the calculation formula (R = V / I) for calculating the resistance component is corrected (initial adjustment) so that the resistance value R of the standard resistor measured by the measurement device 100 matches the theoretical resistance value Rr.

[0079] Next, for example, immediately after the initial adjustment, the measuring device 100 switches the connection destination of the internal terminals hci, hpi, lci, and lpi to the reference resistor Rref using the switch unit 5, and measures the value Rr1 of the reference resistor Rref using the impedance calculation unit 43. Hereinafter, the conditions after the initial adjustment (e.g., temperature, humidity, elapsed time since production of the measuring device 100, operating time, etc.) will be referred to as the "first condition." The measuring device 100 stores the value Rr1 of the reference resistor Rref measured under the first condition in the storage unit 46 as the reference measurement result (first condition) 401. Thereafter, the measuring device 100 is shipped.

[0080] Consider a case where a user measures the impedance of DUT 200 using measurement device 100 after shipment of measurement device 100. Hereinafter, the conditions under which the user performs the measurement (conditions different from the first conditions, such as temperature, humidity, time elapsed since production of measurement device 100, operating time, etc.) will be referred to as "second conditions."

[0081] Under the second condition, when the user operates the measuring device 100 to instruct the execution of a measurement, the measuring device 100 first switches the connection destination of the internal terminals hci, hpi, lci, and lpi to the reference resistor Rref using the switch unit 5, measures the value Rr2 of the reference resistor Rref using the impedance calculation unit 43, and stores the value Rr2 in the memory unit 46 as the reference measurement result (second condition) 402.

[0082] Now, let us assume that, under the second condition, due to temperature changes and changes over time from the time of initial adjustment (first condition), an error of Ei occurs in the gain of the operational amplifier that constitutes the current detection circuit 2, and an error of Ev occurs in the gain of the operational amplifier that constitutes the voltage detection circuit 3. In this case, if the current detected by the voltage detection circuit 3 is I and the value of the reference resistance Rref measured under the first condition is Rr1, then the value Rr2 of the reference resistance Rref measured under the second condition can be expressed by the following equation (1).

[0083]

number

[0084] In the above formula (1), Er (=Ev / Ei) represents the measurement error between the first condition and the second condition.

[0085] As can be seen from the above formula (1), the value Rr2 of the reference resistance Rref measured under the second condition is the value Rr1 of the reference resistance Rref measured under the first condition multiplied by the error component "Er." Therefore, by setting the reciprocal of the error Er as the first correction coefficient Gfix and multiplying the value Rr2 of the resistance component of the impedance of the DUT 200 measured under the second condition by the first correction coefficient Gfix, it is possible to remove the error component contained in the value Rr2 of the resistance component of the impedance of the DUT 200 measured under the second condition.

[0086] Specifically, the correction coefficient update unit 42 calculates the first correction coefficient Gfix based on the value Rr1 of the reference resistance Rref measured under the first condition, the value Rr2 of the reference resistance Rref measured under the second condition, which are stored in the memory unit 46, and the following equation (2).

[0087]

number

[0088] The calculation (updating) of the correction coefficient (first correction coefficient Gfix) by the correction coefficient update unit 42 may be performed, for example, when the instruction receiving unit 40 receives an instruction to perform measurement of the DUT 200, or when the instruction receiving unit 40 receives an instruction to update the correction coefficient or an instruction to perform measurement of the reference circuit 8.

[0089] The correction unit 44 is a functional unit that corrects the impedance value calculated by the impedance calculation unit 43 based on correction coefficient information. The correction unit 44 corrects the value R of the resistance component of the impedance of the DUT 200 calculated by the impedance calculation unit 43 using the first correction coefficient Gfix stored in the storage unit 46, and stores the corrected DUT measurement result (second condition) 404 in the storage unit 46. For example, the correction unit 44 corrects the value R of the resistance component of the impedance by performing a calculation based on the following equation (3).

[0090]

number

[0091] That is, the correction unit 44 stores the value Rf (=R×Gfix) obtained by multiplying the value R of the resistance component of the impedance of the DUT 200 calculated by the impedance calculation unit 43 by the first correction coefficient Gfix in the memory unit 46 as the corrected DUT measurement result (second condition) 404.

[0092] The measurement result output unit 45 is a functional unit that outputs the measurement results. For example, when the impedance of the DUT 200 is measured, the measurement result output unit 45 outputs the impedance measurement result (corrected resistance component value Rf) So corrected by the correction unit 44 to the output unit 6. The output unit 6, for example, displays information corresponding to the received measurement result So on a screen or transmits it as measurement data to an external device.

[0093] Next, the flow of impedance measurement by the measurement device 100 according to the first embodiment will be described.

[0094] FIG. 4 is a flowchart showing the flow of impedance measurement by the measurement device 100 according to the first embodiment.

[0095] Here, it is assumed that the reference measurement result (Rr1) 401 under the first condition is stored in advance in the storage unit 46 of the data processing control circuit 4. It is also assumed that the DUT 200 is connected between the external terminals HC, HP and the external terminals LC, LP, as shown in FIG. 2B.

[0096] For example, when a user operates the operation unit 7 to instruct measurement of the impedance of the DUT 200, the data processing control circuit 4 first controls the switch unit 5 to connect the internal terminals hci, hpi, lci, and lpi to the reference circuit 8 (step S1).

[0097] Specifically, when the instruction receiving unit 40 receives a signal Sd from the operation unit 7 instructing execution of impedance measurement of the DUT 200, the instruction receiving unit 40 instructs the switch control unit 41 to connect the internal terminals hci, hpi, lci, and lpi to the reference resistor Rref. In response to the instruction, the switch control unit 41 controls the switch unit 5 to connect the internal terminal hci to the terminal hcr of the reference circuit, connect the internal terminal hpi to the terminal hpr of the reference circuit, connect the internal terminal lci to the terminal lcr of the reference circuit, and connect the internal terminal lpi to the terminal lpr of the reference circuit.

[0098] Next, the data processing control circuit 4 measures the resistance component Rr2 of the impedance of the reference circuit 8 (reference resistor Rref) (step S2). Specifically, the instruction receiving unit 40 instructs the generating circuit 1 to output a voltage or a current, and instructs the impedance calculation unit 43 to measure the impedance. The impedance calculation unit 43 acquires the voltage value detected by the voltage detection circuit 3 and the current value detected by the current detection circuit 2, calculates the resistance component Rr2 of the reference resistor Rref using the above-mentioned method, and stores it in the storage unit 46 as the reference measurement result 402 under the second condition.

[0099] Next, the data processing control circuit 4 calculates (updates) the first correction coefficient Gfix (step S3). Specifically, the correction coefficient update unit 42 calculates the first correction coefficient Gfix by the above-described method based on the resistance component value Rr1 as the reference measurement result 401 under the first condition and the resistance component value Rr2 as the reference measurement result 402 under the second condition, which are stored in the storage unit 46, and stores the first correction coefficient Gfix in the storage unit 46. Note that if the correction coefficient Gfix has already been stored in the storage unit 46, the correction coefficient update unit 42 rewrites the first correction coefficient Gfix stored in the storage unit 46 with the newly calculated first correction coefficient Gfix.

[0100] Next, the data processing control circuit 4 controls the switch unit 5 to connect the internal terminals hci, hpi, lci, and lpi to the external terminals HC, HP, LC, and LP (step S4). Specifically, the instruction receiving unit 40 instructs the switch control unit 41 to connect the internal terminals hci, hpi, lci, and lpi to the external terminals HC, HP, LC, and LP. In response to the instruction, the switch control unit 41 controls the switch unit 5 to connect the internal terminal hci to the external terminal HC and the internal terminal hpi to the external terminal HP, and to connect the internal terminal lci to the external terminal LC and the internal terminal lpi to the external terminal LP. As a result, the internal terminals hci, hpi, lci, and lpi are connected to the DUT 200.

[0101] Next, the data processing control circuit 4 measures the resistance component of the DUT 200 (step S5). Specifically, similar to step S2, the instruction receiving unit 40 instructs the generation circuit 1 to output a voltage or a current, and instructs the impedance calculation unit 43 to measure the impedance. The impedance calculation unit 43 acquires the voltage value detected by the voltage detection circuit 3 and the current value detected by the current detection circuit 2, calculates the value R of the resistance component of the DUT 200 using the method described above, and stores it in the storage unit 46 as the DUT measurement result 405.

[0102] Next, the data processing control circuit 4 corrects the value R of the resistance component of the DUT 200 measured in step S5 (step S6). Specifically, the correction unit 44 calculates the corrected value Rf of the resistance component of the DUT 200 by the above-mentioned method based on the value R of the resistance component of the DUT 200 stored in the storage unit 46 and the first correction coefficient Gfix stored in the storage unit 46, and stores it in the storage unit 46 as the corrected DUT measurement result 405.

[0103] Next, the data processing control circuit 4 outputs the corrected DUT measurement result 405 (Rf) to the output unit 6 as the measurement result of the resistance component of the impedance of the DUT 200 (step S7). For example, the output unit 6 displays information on the measurement result of the impedance of the DUT 200 (Rf, etc.) on a screen.

[0104] As described above, the measuring apparatus 100 according to the first embodiment has a built-in reference circuit 8 having a predetermined impedance that can be connected to the internal terminals hci, hpi, lci, and lpi. This allows the user to measure the impedance of the reference circuit 8 under various conditions using the measuring apparatus 100 and compare the measurement results, thereby easily determining the error in the measurements made by the measuring apparatus 100.

[0105] Furthermore, the measurement apparatus 100 corrects the measurement result of the impedance of the device under test (DUT) 200 under the second condition based on the error between the measurement result of the impedance of the reference circuit 8 under the first condition and the measurement result of the impedance of the reference circuit 8 under the second condition different from the first condition.

[0106] This allows for more accurate impedance measurements, even if an error occurs in the measurement by the measuring device 100 due to changes in the characteristics of the internal circuitry of the measuring device 100 due to temperature and aging, as the measuring device 100 itself corrects the error. For example, if the user performs initial adjustment at a room temperature of 18°C as a first condition and measures DUT 200 at a room temperature of 28°C as a second condition, a conventional measurement apparatus would have to consider the influence of a temperature difference of 10°C. In contrast, with measurement apparatus 100 according to the first embodiment, if the first correction coefficient Gfix is updated at a room temperature of 27°C, the user only needs to consider the influence of a temperature difference of 1°C on the measurement results under the second condition (room temperature of 28°C), enabling more accurate measurements.

[0107] Specifically, the data processing control circuit 4 of the measurement device 100 corrects the value R of the resistance component of the impedance of the DUT 200 measured under the second condition based on the error between the value Rr1 of the resistance component of the impedance of the reference circuit 8 (reference resistor Rref) measured under the first condition and the value Rr2 of the resistance component of the impedance of the reference circuit 8 (reference resistor Rref) measured under the second condition. This allows for more accurate measurement of the resistance component of impedance even when errors occur in the measurement of the resistance component of impedance by the measurement device 100 due to temperature and aging.

[0108] More specifically, the data processing control circuit 4 of the measurement device 100 calculates a first correction coefficient Gfix (=Rr1 / Rr2) based on the ratio between the value Rr1 of the resistance component of the impedance of the reference circuit 8 measured under the first condition and the value Rr2 of the resistance component of the impedance of the reference circuit 8 measured under the second condition, and corrects the value R of the resistance component of the impedance of the DUT 200 measured under the second condition using the first correction coefficient Gfix (Rf=R×Gfix). This makes it possible to easily correct the measured value of the resistance component of the impedance without using a complex arithmetic expression.

[0109] Furthermore, in the measurement device 100, when the instruction receiving unit 40 receives a predetermined instruction, the switch unit 5 connects one terminal hcr, hpr of the reference circuit 8 to the internal terminals hci, hpi and connects the other terminal lcr, lpr of the reference circuit 8 to the internal terminals lci, lpi, and the impedance calculation unit 43 calculates the value Rr2 of the resistance component of the impedance of the reference circuit 8 under the second condition and stores it in the memory unit 46. Then, the correction coefficient update unit 42 may update the first correction coefficient Gfix based on the value Rr1 of the resistance component of the impedance of the reference circuit 8 under the first condition and the value Rr2 of the resistance component of the impedance of the reference circuit 8 under the second condition, which are stored in the memory unit 46.

[0110] Here, the predetermined instruction may be, for example, an instruction to perform measurement of the DUT 200, an instruction to perform update of the correction coefficient, or an instruction to perform measurement of the impedance of the reference circuit 8.

[0111] This allows the first correction coefficient Gfix to be updated at a timing desired by the user, thereby realizing a measurement device that is easy for the user to use.

[0112] Some conventional measuring devices, such as LCR meters, ohmmeters, and battery testers, have a so-called self-calibration function. However, conventional self-calibration only corrects errors in certain circuits, such as voltage detection circuits and current detection circuits, and only achieves a limited correction effect. Furthermore, to achieve the self-calibration function, a separate reference signal output circuit, consisting of a regulator IC that generates a reference voltage, an attenuator, a D / A conversion circuit, and other components, is required depending on the circuit to be corrected, which increases the complexity of the circuit and increases costs.

[0113] In contrast, in the measurement apparatus 100 according to the above embodiment, the reference circuit 8 itself has an impedance and functions as a measurement target similar to a DUT. Therefore, it is possible to comprehensively correct measurement errors in the entire measurement apparatus by using the measurement error in the impedance of the reference circuit 8, without having to measure errors in the current detection circuit, voltage detection circuit, etc. individually and perform self-calibration for each circuit. Furthermore, by employing a simple circuit configuration for the reference circuit 8 as described above (see FIG. 2A), it is possible to minimize the increase in circuit complexity and cost that would otherwise result from adding a measurement error correction function to the measurement apparatus 100.

[0114] Second Embodiment FIG. 5 is a diagram showing the configuration of a measurement device 100A according to the second embodiment.

[0115] The measurement device 100A according to the second embodiment shown in FIG. 5 differs from the measurement device 100 according to the first embodiment in that it has a function of correcting the measured value of the phase angle of the impedance of the object to be measured, but is otherwise similar to the measurement device 100 according to the first embodiment.

[0116] Generally, circuits such as voltage detection circuits and current detection circuits that make up measuring devices such as the above-mentioned LCR meters each have their own phase characteristics. That is, when a signal is input to a circuit, a phase shift occurs between the signal input to the circuit and the signal output from the circuit. The amount of this phase shift is also called the "phase characteristic."

[0117] The phase characteristics of a circuit depend on the characteristics of the electronic components that make up the circuit, such as operational amplifier circuits and capacitors. Therefore, if the characteristics of the electronic components change due to temperature or aging, the phase characteristics of the internal circuits that make up the measurement device also change.

[0118] Therefore, the measurement device 100A according to the second embodiment has a function to reduce the influence of not only the measurement error of the resistance component of the impedance but also the phase measurement error due to temperature and aging. Specifically, the measurement device 100A has a reference circuit 8A having a predetermined impedance, and a data processing control circuit 4A that calculates a correction coefficient based on the measurement result of the phase angle of the impedance of the object to be measured by the reference circuit 8A, and corrects the measurement result of the phase angle of the impedance of the object to be measured.

[0119] Here, the phase angle of impedance is the difference between the phase of the current flowing through the measurement target (DUT, reference circuit 8A, etc.) and the phase of the voltage of the measurement target. When the resistance component of the impedance is R and the reactance component of the impedance is X, the phase angle θ is expressed as follows: θ=tan -1 It is expressed as "(X / R)".

[0120] FIG. 6 is a diagram showing an example of a reference circuit 8A according to the second embodiment.

[0121] As shown in Fig. 6, the reference circuit 8A is configured to include electronic components having a predetermined impedance. In the second embodiment, the reference circuit 8A is configured to include a reference resistor Rref, similar to the reference circuit 8 according to the first embodiment. That is, as shown in Fig. 6, one terminal of the reference resistor Rref is connected to the terminals hcr and hpr of the reference circuit 8A, and the other terminal of the reference resistor Rref is connected to the terminals lcr and lpr of the reference circuit 8A.

[0122] The reference circuit 8A is not limited to the above-mentioned reference resistor Rref, and may be configured to include a capacitor, an inductor, or the like having a highly accurate reactance component.

[0123] In the measurement apparatus 100A according to the second embodiment, the data processing control circuit 4A has the function of reducing the influence of errors in phase measurement in addition to the functions of the data processing control circuit 4 according to the first embodiment.

[0124] As a function of reducing the influence of errors in phase measurement, the data processing control circuit 4A corrects the measurement result of the phase angle of the impedance of the DUT 200 measured under the second condition based on the error between the value of the phase angle of the impedance of the reference circuit 8 (reference resistor Rref) measured under the first condition and the value of the phase angle of the impedance of the reference circuit 8 measured under the second condition.

[0125] Specifically, the data processing control circuit 4A calculates a second correction coefficient θfix based on the difference between the phase angle value θr1 of the impedance of the reference circuit 8A (reference resistor Rref) measured under the first condition and the phase angle value θr2 of the impedance of the reference circuit 8A measured under the second condition, and corrects the phase angle value of the impedance of the DUT200 measured under the second condition based on the second correction coefficient θfix.

[0126] FIG. 7 is a diagram showing the configuration of a data processing control circuit 4A according to the second embodiment.

[0127] The data processing control circuit 4A is, for example, a program processing device, similar to the data processing control circuit 4 according to the first embodiment. The data processing control circuit 4A has, as functional blocks for realizing the above-described functions, an instruction receiving unit 40, a switch control unit 41, a correction coefficient updating unit 42A, an impedance calculation unit 43A, a correction unit 44A, a measurement result output unit 45, and a storage unit 46A. These functional blocks are realized, for example, by a processor in a program processing unit (MCU) serving as the data processing control circuit 4A, executing various arithmetic processes in accordance with programs stored in a storage device and controlling peripheral circuits. Note that some or all of the above functional blocks may be realized by dedicated logic circuits.

[0128] Similar to the memory unit 46 according to the first embodiment, the memory unit 46A is a functional unit that stores the arithmetic formulas, various parameters, measurement results, and correction coefficients required to measure the electrical characteristics of the DUT and calculate the correction coefficients.

[0129] For example, the memory unit 46A stores a reference measurement result (first condition) 401A including the value (Rr1, θr1) of the reference resistance Rref measured under the first condition, a reference measurement result (second condition) 402A including the measurement value (Rr2, θr2) of the reference resistance Rref measured under the second condition, correction coefficient information 403A including the first correction coefficient Gfix and the second correction coefficient θfix, a DUT measurement result (second condition) 404A including the impedance value (R, θ) of the DUT 200 measured under the second condition, and a corrected DUT measurement result (second condition) 405A including the corrected impedance value (Rf, θf) of the DUT 200, as described below.

[0130] The impedance calculation unit 43A is a functional unit that calculates the value of the impedance between the internal terminals hpi and lpi. The impedance calculation unit 43A calculates the value of the impedance between the internal terminals hpi and lpi based on the value of the voltage detected by the voltage detection circuit 3 and the value of the current detected by the current detection circuit 2.

[0131] The impedance calculation unit 43A has the function of calculating the phase angle of the impedance between the internal terminals hpi and lpi in addition to the function of the impedance calculation unit 43 according to the first embodiment.

[0132] For example, when the instruction receiving unit 40 instructs the DUT 200 to measure the phase angle of the impedance, update the correction coefficient, or measure the reference circuit 8A, the generating circuit 1 applies an AC signal (e.g., a constant current signal) between the internal terminals hci and lci, the current detection circuit 2 detects the current flowing between the internal terminals hci and lci at this time, and the voltage detection circuit 3 detects the voltage between the internal terminals hcp and lcp.

[0133] The impedance calculation unit 43A calculates the value of the phase angle of the impedance between the internal terminals hpi and lpi using a known method based on the current detected by the current detection circuit 2 and the voltage detected by the voltage detection circuit 3.

[0134] For example, the impedance calculation unit 43A calculates, by synchronous detection, the amplitude |V| of the voltage signal v detected by the voltage detection circuit 3, the voltage phase difference θv between the reference signal and the voltage signal v in the synchronous detection, the amplitude |I| of the current signal i detected by the current detection circuit 2, and the current phase difference θi between the reference signal and the current signal i in the synchronous detection. Then, using the calculated amplitude |V| of the voltage signal v, voltage phase difference θv, amplitude |I| of the current signal i, and current phase difference θi, the impedance calculation unit 43A calculates the magnitude |Z|=|V| / |I| and phase θ=θv-θi between the internal terminals hpi and lpi. As a result, the value R of the resistance component of the impedance can be calculated by "R=Zcosθ," and the value X of the reactance component of the impedance can be calculated by "X=Zsinθ."

[0135] As will be described later, when an initial adjustment is performed in the same manner as in embodiment 1, a correction coefficient or the like obtained by the initial adjustment may be included in the above formula (|Z|=|V| / |I|, θ=φv-φi). Furthermore, the above-described method of calculating impedance based on synchronous detection is just one example, and the impedance calculation unit 43A may calculate the impedance using other known calculation methods.

[0136] The correction coefficient update unit 42A is a functional unit that updates the correction coefficients. The correction coefficient update unit 42A calculates and updates the first correction coefficient Gfix, similarly to the correction coefficient update unit 42 according to embodiment 1. Furthermore, the correction coefficient update unit 42A calculates and updates the second correction coefficient θfix.

[0137] The second correction coefficient θfix is a coefficient for correcting the measured value of the phase angle of the impedance of the measurement object. The correction coefficient update unit 42A calculates the second correction coefficient θfix based on the difference between the value θr1 of the phase angle of the impedance of the reference circuit 8A (reference resistor Rref) measured under the first condition and the value θr2 of the phase angle of the impedance of the reference circuit 8A measured under the second condition, both of which are stored in the storage unit 46, and stores the calculated second correction coefficient θfix in the storage unit 46A. The method for calculating the second correction coefficient θfix will be described in detail below.

[0138] For example, when the measurement apparatus 100A is manufactured or shipped, a standard resistor having a highly accurate phase angle or an ideal reactance element having a highly accurate phase angle is connected to the measurement apparatus 100A as a DUT, and the measurement apparatus 100A measures the phase angle of the impedance of the DUT. Then, the equation (θ=θv-θi) used by the impedance calculation unit 43 for calculating the impedance phase angle is corrected (initial adjustment) so that the difference (phase difference) between the theoretical phase angle of the DUT (or the calibrated (known) phase angle) and the measured phase angle of the DUT becomes "zero." At this time, the measurement apparatus 100A may also adjust the equation for calculating the resistance component, as in the first embodiment.

[0139] Next, for example, immediately after the initial adjustment, the measurement device 100A switches the connection destination of the internal terminals hci, hpi, lci, and lpi to the reference circuit 8 (reference resistor Rref) using the switch unit 5, and measures the phase value θr1 of the reference resistor Rref using the above-mentioned method using the impedance calculation unit 43A. Hereinafter, the condition after the initial adjustment is referred to as the "first condition." The measurement device 100A stores the phase value θr1 of the reference resistor Rref measured under the first condition in the storage unit 46 as a reference measurement result (first condition) 401A. At this time, the phase value θr1 of the reference resistor Rref measured under the first condition is expressed by the following equation (4): where θv is the voltage phase difference, and θi is the current phase difference.

[0140]

number

[0141] As in the first embodiment, the measurement apparatus 100A also measures the value Rr1 of the resistance component of the reference resistor Rref and stores it in the storage unit 46A together with the measured phase value. Thereafter, the measuring device 100A is shipped.

[0142] Consider a case where, after shipping of measurement apparatus 100A, a user uses measurement apparatus 100A to measure the impedance of DUT 200. Hereinafter, the condition under which the user performs measurement will be referred to as the "second condition."

[0143] Under the second condition, when the user operates the measurement device 100 to instruct execution of measurement, the measurement device 100A first switches the connection destination of the internal terminals hci, hpi, lci, and lpi to the reference resistor Rref using the switch unit 5, measures the phase value θr2 of the reference resistor Rref using the impedance calculation unit 43A, and stores this as a reference measurement result (second condition) 402A in the storage unit 46A. At this time, the measurement device 100A also measures the value Rr2 of the resistance component of the reference resistor Rref, as in the first embodiment, and stores this together with the measured phase value in the storage unit 46A.

[0144] Now, assume that the phase characteristics of the current detection circuit 2 and the voltage detection circuit 3 have changed due to temperature changes and aging since the time of initial adjustment (first condition), and that under the second condition, a phase error θe has occurred between the output signal of the current detection circuit 2 and the output signal of the voltage detection circuit 3. In this case, the phase value θr2 of the reference resistance Rref measured under the second condition can be expressed by the following equation (5).

[0145]

number

[0146] As can be seen from the above equation (5), the phase value θr2 of the reference resistor Rref measured under the second condition is the value obtained by adding the phase error θe to the phase value θr1 of the reference resistor Rref measured under the first condition. In other words, the phase error θe between the output signal of the current detection circuit 2 and the output signal of the voltage detection circuit 3 appears as the error between the phase value θr1 of the reference resistor Rref measured under the first condition and the phase value θr2 of the reference resistor Rref measured under the second condition. Therefore, from the above equation (5), the phase error θe is expressed by the following equation (6):

[0147]

number

[0148] As can be seen from the above equation (6), the phase error θe can be calculated by obtaining the phase value θr1 of the reference resistor Rref measured under the first condition and the phase value θr2 of the reference resistor Rref measured under the second condition.

[0149] Therefore, by setting the phase error θe (=θr2-θr1) as the second correction coefficient θfix (=θr2-θr1) and subtracting the second correction coefficient θfix (=θe) from the phase angle value θ (=θv-θi+θe) of the impedance of DUT200 measured under the second condition, it is possible to remove the error component (θe) contained in the phase angle value θ of the impedance of DUT200 measured under the second condition.

[0150] The calculation (updating) of the correction coefficients (first correction coefficient Gfix and second correction coefficient θfix) by the correction coefficient update unit 42A may be performed, for example, when the instruction receiving unit 40 receives an instruction to perform measurement of the DUT 200, or when the instruction receiving unit 40 receives an instruction to update the correction coefficients or an instruction to perform measurement of the reference circuit 8. .

[0151] The correction unit 44A is a functional unit that corrects the impedance value calculated by the impedance calculation unit 43A based on correction coefficient information 403A.

[0152] Specifically, the correction unit 44A uses the first correction coefficient Gfix included in the correction coefficient information 403A to correct the value R of the resistance component of the impedance of the DUT 200 calculated by the impedance calculation unit 43A in a manner similar to that of the correction unit 44.

[0153] Furthermore, the corrector 44A corrects the phase angle value θ of the impedance of the DUT 200 calculated by the impedance calculator 43A using a second correction coefficient θfix (=θe) included in correction coefficient information 403A stored in the memory 46A, and stores the corrected DUT measurement result (second condition) 405A in the memory 46. For example, the corrector 44A corrects the phase angle value θ of the impedance of the DUT 200 by performing a calculation based on the following equation (7).

[0154]

number

[0155] That is, the correction unit 44A stores the value θf (=θ-θfix) obtained by subtracting the second correction coefficient θfix (=θe) from the phase angle value θ of the impedance of the DUT 200 calculated by the impedance calculation unit 43A in the memory unit 46A as the corrected DUT measurement result (second condition) 405A.

[0156] For example, when the impedance of the DUT 200 is measured, the measurement result output unit 45 outputs the impedance measurement result So corrected by the correction unit 44A (corrected resistance component value Rf, phase θf, etc.) to the output unit 6. The output unit 6 displays information corresponding to the received measurement result So on a screen, or transmits it to an external device as measurement data, for example.

[0157] Next, the flow of impedance measurement by the measurement device 100A according to the second embodiment will be described.

[0158] FIG. 8 is a flowchart showing the flow of impedance measurement by the measurement device 100A according to the second embodiment.

[0159] The following describes, as an example, the flow of measuring the phase of the DUT 200, and omits the flow of measuring the resistance component of the DUT 200. The flow of measuring the resistance component is the same as that shown in FIG. 4, which has already been described.

[0160] Here, it is assumed that the reference measurement result (θr1) 401A under the first condition is stored in advance in the storage unit 46A of the data processing control circuit 4A, and that the DUT 200 is connected between the external terminals HC, HP and the external terminals LC, LP.

[0161] For example, when a user operates the operation unit 7 to instruct measurement of the impedance of the DUT 200, the data processing control circuit 4A first controls the switch unit 5 to connect the internal terminals hci, hpi, lci, and lpi to the reference circuit 8 (step S1A), similar to step S1 in the first embodiment described above.

[0162] Next, the data processing control circuit 4A measures the phase angle θr2 of the impedance of the reference circuit 8A (reference resistor Rref) (step S2A). Specifically, the instruction receiving unit 40 instructs the generating circuit 1 to output a voltage or a current, and instructs the impedance calculation unit 43A to measure the impedance. The impedance calculation unit 43A calculates the phase θr2 of the reference resistor Rref using the above-mentioned method based on the voltage signal output from the voltage detection circuit 3 and the current signal output from the current detection circuit 2, and stores it in the storage unit 46A as a reference measurement result 402A of the second condition.

[0163] Next, the data processing control circuit 4A calculates (updates) the second correction coefficient θfix (step S3A). Specifically, the correction coefficient update unit 42A calculates the second correction coefficient θfix by the above-mentioned method based on the phase value θr1 as reference measurement result 401A under the first condition and the phase value θr2 as reference measurement result 402A under the second condition, which are stored in the storage unit 46A, and stores the second correction coefficient θfix in the storage unit 46A. Note that if the second correction coefficient θfix has already been stored in the storage unit 46A, the correction coefficient update unit 42A rewrites the second correction coefficient θfix stored in the storage unit 46A with the newly calculated second correction coefficient θfix.

[0164] Next, the data processing control circuit 4A controls the switch unit 5 to connect the internal terminals hci, hpi, lci, and lpi to the external terminals HC, HP, LC, and LP (step S4A). As a result, the internal terminals hci, hpi, lci, and lpi are connected to the DUT 200.

[0165] Next, the data processing control circuit 4A measures the phase of the DUT 200 (step S5A). Specifically, similar to step S2A, the instruction receiving unit 40 instructs the generation circuit 1 to output a voltage or a current, and instructs the impedance calculation unit 43A to measure the impedance. The impedance calculation unit 43A calculates the phase value θ of the DUT 200 using the method described above based on the voltage signal output from the voltage detection circuit 3 and the current signal output from the current detection circuit 2, and stores the calculated value in the storage unit 46A as the DUT measurement result 404A.

[0166] Next, the data processing control circuit 4A corrects the phase value θ of the DUT 200 measured in step S5A (step S6A). Specifically, the correction unit 44A corrects the phase value θ of the DUT 200 measured in step S5A by the above-mentioned method using the second correction coefficient θfix stored in the storage unit 46A, and stores the corrected phase value θf (=θ-θfix) of the DUT 200 in the storage unit 46A as the corrected DUT measurement result 405A.

[0167] Next, the data processing control circuit 4 outputs the corrected DUT measurement result 405A (θf) to the output unit 6 as the measurement result of the phase angle of the impedance of the DUT 200 (step S7A). The output unit 6 displays, for example, information on the measurement result of the impedance of the DUT 200 (phase θf, etc.) on a screen.

[0168] As described above, in the measurement apparatus 100A according to the second embodiment, the data processing control circuit 4A corrects the measurement result (θ) of the phase angle of the impedance of the DUT 200 measured under the second condition based on the difference (phase error θe) between the phase angle value θr1 of the impedance of the reference circuit 8A measured under the first condition and the phase angle value θr2 of the impedance of the reference circuit 8A measured under the second condition. This allows for more accurate measurement of the impedance phase angle even when an error occurs in the measurement of the impedance phase angle by the measurement device 100A due to temperature and aging.

[0169] Specifically, the data processing control circuit 4A of the measurement device 100A calculates a second correction coefficient θfix (=θr1-θr2) based on the difference between the phase angle value θr1 of the impedance of the reference circuit 8A measured under the first condition and the phase angle value θr2 of the impedance of the reference circuit 8A measured under the second condition, and corrects the phase angle value θ of the impedance of the DUT 200 measured under the second condition using the second correction coefficient θfix. This makes it possible to easily correct the measured value of the phase angle of the impedance without using a complex arithmetic expression.

[0170] Furthermore, in the measurement device 100A, when the instruction receiving unit 40 receives a predetermined instruction, the switch unit 5 connects one terminal hcr, hpr of the reference circuit 8A to the internal terminals hci, hpi and connects the other terminal lcr, lpr of the reference circuit 8A to the internal terminals lci, lpi, and the impedance calculation unit 43A stores the value (θr2) of the phase angle of the impedance of the reference circuit 8A under the second condition in the memory unit 46. Then, the correction coefficient update unit 42A may update the second correction coefficient θfix(θr1-θr2) based on the value (θr1) of the phase angle of the impedance of the reference circuit 8A under the first condition and the value (θr2) of the phase angle of the impedance of the reference circuit 8A under the second condition, which are stored in the memory unit 46A. Here, the predetermined instruction may be an instruction to measure the DUT 200, an instruction to update the correction coefficient, or an instruction to measure the impedance of the reference circuit 8A. According to this, the second correction coefficient θfix can be updated at a timing desired by the user, and therefore a measurement device that is easy for the user to use can be realized.

[0171] Third Embodiment FIG. 9 is a diagram showing the configuration of a measurement device 100B according to the third embodiment. The measurement device 100B according to the third embodiment shown in FIG. 9 differs from the measurement devices 100 and 100A according to the first and second embodiments in that it is capable of correcting the impedance measurement according to the measurement range, but is otherwise similar to the measurement devices 100 and 100A according to the first and second embodiments.

[0172] Generally, measurement devices such as the LCR meter described above have multiple measurement ranges. For example, when measuring a resistor with a resistance of several milliohms, the user can select the measurement range corresponding to "mΩ" and measure the resistance value within that measurement range, thereby enabling more accurate measurement of the resistance value.

[0173] On the other hand, in order to appropriately correct measurement errors due to temperature and aging in the "mΩ" measurement range of the measurement device, it is preferable to use a resistor with a resistance value in the "mΩ" unit as a reference circuit and correct the measurement error using a method similar to that of the first and second embodiments. However, it is not easy to obtain a resistor in the "mΩ" unit with sufficiently excellent temperature characteristics and long-term stability for use in a reference circuit. Even if such a resistor were available, it would result in an increase in component costs. Therefore, the reference circuit 8B according to the third embodiment realizes a pseudo-desired resistance value without using a highly stable resistor having a low resistance value such as a few mΩ, thereby enabling correction of measurement errors in the low resistance measurement range.

[0174] FIG. 10 is a diagram showing an example of a reference circuit 8B according to the third embodiment.

[0175] As shown in FIG. 10, the reference circuit 8B includes a high-side input terminal hcr, a high-side output terminal hpr, a low-side input terminal lcr, a low-side output terminal lpr, a voltage divider circuit 80, a selection circuit (MUX) 81, and a buffer 82.

[0176] In FIG. 10, for convenience of illustration, the terminals hcr, hpr, lcr, and lpr are shown outside the dotted line indicating the reference circuit 8B.

[0177] The high-side input terminal hcr is connectable to the internal terminal hci by a switch 51. The high-side output terminal hpr is connectable to the internal terminal hpi by a switch 52. The low-side input terminal lcr is connectable to the internal terminal lci by a switch 53. The low-side output terminal lpr is connectable to the internal terminal lpi by a switch 54.

[0178] The voltage dividing circuit 80 is a circuit that divides (attenuates) the voltage between the high-side input terminal hcr and the low-side input terminal lcr and outputs the divided voltage.

[0179] Generally, most measurement devices that measure the resistance of a DUT using the four-terminal method, such as an LCR meter, apply a constant current signal or voltage signal to the DUT to generate a voltage across the DUT, detect that voltage, and calculate the resistance (= voltage / current) of the DUT based on Ohm's law, as described above. In this case, the resistance calculated based on Ohm's law is proportional to the detected voltage.

[0180] Taking this into consideration, in the measuring device 100B according to the third embodiment, the reference circuit 8B is realized using a voltage divider circuit 80 composed of a plurality of resistors, and the voltage generated in the reference circuit 8B is divided by the voltage divider circuit 80 and input to the voltage detection circuit 3. As a result, when the measuring device 100B calculates the resistance value, the reference circuit 8B behaves like a resistor having a predetermined resistance value.

[0181] For example, as shown in FIG. 10, the voltage dividing circuit 80 includes a first resistor Rm and a plurality of second resistors Ra1 to Ran (n is an integer of 2 or more) connected in parallel with the first resistor Rm.

[0182] The first resistor Rm is connected between the high-side input terminal hcr and the low-side input terminal lcr, and is preferably a precision resistor having high accuracy and high reliability, similar to the reference resistor Rref in the first and second embodiments.

[0183] The plurality of second resistors Ra1 to Ran are connected in series between the high-side input terminal hcr and the low-side input terminal lcr. The number of second resistors Ra1 to Ran connected in series may be determined according to the number n of resistance measurement ranges of measurement device 100A. In the third embodiment, as an example, description will be given assuming that measurement device 100B has three (n=3) resistance measurement ranges, and that three second resistors Ra1 to Ra3 are connected in series between the high-side input terminal hcr and the low-side input terminal lcr.

[0184] The second resistors Ra1 to Ran include, for example, a plurality of resistors connected in series and are so-called network resistors encapsulated in one package. Here, some of the second resistors Ra1 to Ran may be connected in parallel. That is, the above network resistor may have a configuration in which not only a series circuit of resistors but also resistors are connected in parallel to the series circuit. Hereinafter, the second resistors Ra1 to Ran may be collectively referred to as "network resistor Ratt".

[0185] Similar to the first resistor Rm, the second resistors Ra1 to Ran are preferably resistors having high precision and high reliability. However, it is not necessarily required that each of the second resistors Ra1 to Ran has the same level of high precision and high reliability as the first resistor Rm. At least, it is sufficient that the second resistors Ra1 to Ran are relatively highly precise and reliable with respect to each other. For example, the second resistors Ra1, Ra2, and Ra3 are preferably precision network resistors in which the relative temperature coefficient of the resistance value between the resistors is ±5 ppm / °C or less and the relative value of the long-term stability of the resistance value between the resistors is ±100 ppm / year or less.

[0186] In the voltage dividing circuit 80, the series resistance value of the network resistor Ratt, that is, the series resistance value from the second resistor Ra1 to the second resistor Ran, is sufficiently larger than the resistance value of the first resistor Rm (Rm << Ratt). For example, the series resistance value of the network resistor Ratt is 100 times or more the resistance value of the first resistor Rm. As a result, since Rm << Ratt, when the reference circuit 8B is connected to the internal terminals hci, lci, hpi, and lpi, the current flowing through the voltage dividing circuit 80 is dominated by the current flowing through the first resistor Rm.

[0187] When the resistance value of the first resistor Rm is Rm and the resistance value (series resistance value) of the network resistor Ratt is Ratt, the resistance value of the voltage dividing circuit 80, that is, the combined resistance value Rcomb of the first resistor Rm and the network resistor Ratt, is represented by the following formula (8).

[0188]

Equation

[0189] When a constant current signal is applied to the voltage dividing circuit 80 by the generating circuit 1 and the current flowing through the voltage dividing circuit 80 (the current detected by the current detection circuit 2) is defined as I, the voltage V generated in the voltage dividing circuit 80 is “V = I × Rcomb”.

[0190] Also, when the voltage division coefficient Xatt (≤ 1) of the network resistor Ratt is considered, the voltage Vatt divided by the voltage dividing circuit 80 is “Vatt = Xatt × V”.

[0191] Therefore, when the resistance value of the reference circuit 8B (reference resistor) calculated by the measuring device 100B is defined as Rref, the following formula (9) can be obtained.

[0192]

Equation

[0193] As understood from the above formula (9), the resistance value Rref of the reference circuit 8B can be set to a desired value by adjusting the combined resistance value Rcomb and the voltage division coefficient Xatt.

[0194] Here, since Rm << Ratt, Rcomb ≈ Rm. Therefore, the variation of the combined resistance value Rcomb with temperature and over time is dominated by the variation of the first resistor Rm, and the variation of the network resistor Ratt can be ignored. Therefore, as described above, by adopting a precision resistor with high precision and high reliability (high stability) as the first resistor Rm, the combined resistance value Rcomb will also exhibit high precision and high reliability.

[0195] Furthermore, as described above, by adopting a precision network resistor as the network resistor Ratt, in which the resistance values between the second resistors Ra1 to Ran are relatively highly accurate and highly reliable (highly stable), the voltage division coefficient Xatt also exhibits high accuracy and high reliability.

[0196] In this way, the voltage dividing circuit 80 can simulate a reference resistor that has a desired resistance value, high accuracy, and high reliability.

[0197] A specific example of the configuration of the reference circuit 8B will be described below, in which a 10 mΩ resistor and a 100 mΩ resistor are realized in a pseudo manner by the reference circuit 8B.

[0198] For example, as shown in Fig. 10, the first resistor Rm is set to 1Ω. Also, in the network resistor Ratt, the second resistor Ra1 is set to 9 kΩ, the second resistor Ra2 is set to 900Ω, and the second resistor Ra1 is set to 100Ω.

[0199] In this case, when the internal terminals hci, lci, hpi, and lpi are connected to the reference circuit 8B by the switch unit 5 and a constant current signal is applied from the generating circuit 1 to the reference circuit 8B, the voltage (Xatt=0.01) at the terminal Pa3 of the network resistor Ratt becomes equivalent to the voltage generated in the reference resistor of 10 mΩ when a constant current signal is applied to the reference resistor.

[0200] Similarly, the voltage (Xatt=0.1) at terminal Pa2 of network resistor Ratt is equivalent to the voltage generated across a reference resistor of 100 mΩ when a constant current signal is applied to the reference resistor, and the voltage (Xatt=1) at terminal Pa1 of network resistor Ratt is equivalent to the voltage generated across the reference resistor when a constant current signal is applied to a reference resistor of 1 Ω.

[0201] In this way, by setting the resistance value of each resistor constituting the voltage dividing circuit 80, it is possible to realize pseudo resistors of 10 mΩ and 100 mΩ without using resistors with resistance values lower than 1 Ω.

[0202] The selection circuit 81 is a circuit that selects and outputs one voltage from among multiple input voltages. The selection circuit 81 is, for example, a multiplexer. The selection circuit 81 is, for example, configured by an IC including multiple transistors, a mechanical relay, or the like.

[0203] The selection circuit 81 receives the voltage between the high-side input terminal hcr and the low-side input terminal lcr (the voltage at terminal Pa1) and a plurality of voltages (the voltages at terminals Pa2 and Pa3) divided by the voltage divider circuit 80, selects one of the input voltages, and outputs it between the high-side output terminal hpr and the low-side output terminal lpr.

[0204] Specifically, a selection signal Ss that specifies the measurement range of the measurement device 100 is input to the selection circuit 81. The selection circuit 81 selects and outputs a voltage that corresponds to the measurement range specified by the selection signal Ss from among the multiple input voltages.

[0205] For example, when the selection signal Ss selects a measurement range of resistance of "1Ω", the selection circuit 81 selects and outputs the voltage (equivalent to 1Ω) at the terminal Pa1 of the network resistor Ratt. When the selection signal Ss selects a measurement range of resistance of "100mΩ", the selection circuit 81 selects and outputs the voltage (equivalent to 100mΩ) at the terminal Pa2 of the network resistor Ratt. When the selection signal Ss selects a measurement range of resistance of "10mΩ", the selection circuit 81 selects and outputs the voltage (equivalent to 10mΩ) at the terminal Pa3 of the network resistor Ratt.

[0206] The buffer 82 is a circuit that receives a signal with high input impedance and outputs a signal with low output impedance. The buffer 82 may be, for example, an operational amplifier.

[0207] The buffer 82 outputs the voltage output from the selection circuit 81 between the high-side output terminal hpr and the low-side output terminal lpr. As a result, the voltage output from the reference circuit 8B (voltage dividing circuit 80) is input to the voltage detection circuit 3.

[0208] For example, when the output impedance of the selection circuit 81 is sufficiently low or when the input impedance of the voltage detection circuit 3 is sufficiently high, the reference circuit 8B does not need to include the buffer 82. That is, the voltage output from the selection circuit 81 may be directly input between the high-side output terminal hpr and the low-side output terminal lpr (between the input terminals of the voltage detection circuit 3).

[0209] Next, the correction of measurement errors by the data processing control circuit 4B using the reference circuit 8B will be described.

[0210] FIG. 11 is a diagram showing the configuration of a data processing control circuit 4B according to the third embodiment.

[0211] In addition to the functions of the data processing control circuits 4 and 4A according to the first and second embodiments, the data processing control circuit 4B has the function of calculating (updating) the correction coefficient and correcting the impedance measurement results for each specified measurement range.

[0212] The data processing control circuit 4B is a program processing device, similar to the data processing control circuits 4 and 4A according to the first and second embodiments. As shown in FIG. 11, the data processing control circuit 4B has, as functional blocks for implementing the above-described functions, an instruction receiving unit 40B, a switch control unit 41, a correction coefficient updating unit 42B, an impedance calculation unit 43A, a correction unit 44B, a measurement result output unit 45, and a storage unit 46B. These functional blocks are implemented, for example, by a processor in a program processing unit (MCU) serving as the data processing control circuit 4B executing various arithmetic operations in accordance with programs stored in a storage device and controlling peripheral circuits. Note that some or all of the above functional blocks may be implemented by dedicated logic circuits.

[0213] The instruction receiving unit 40B, like the instruction receiving unit 40 according to the first and second embodiments, receives a signal Sd from the operation unit 7 and outputs a signal to other functional units instructing them to execute processing in accordance with the signal Sd.

[0214] For example, when a user operates the operation unit 7 to specify a measurement range and instruct the execution of measurement of the impedance of DUT200, the instruction receiving unit 40 provides a selection signal Ss specifying the measurement range to the reference circuit 8B in response to the signal Sd output from the operation unit 7, and instructs the switch control unit 41, the correction coefficient update unit 42B, the impedance calculation unit 43B, etc. to execute processing to measure the impedance of DUT200.

[0215] Similar to the impedance calculation units 43 and 43A according to the first and second embodiments, the impedance calculation unit 43B calculates the impedance value between the internal terminals hpi and lpi based on the voltage value detected by the voltage detection circuit 3 and the current value detected by the current detection circuit 2.

[0216] For example, in the first condition, when measuring the impedance of the reference circuit 8B according to the measurement range k (1 < k ≤ n), the instruction reception unit 40B outputs a selection signal Ss specifying the measurement range k, and the reference circuit 8B inputs a voltage corresponding to the measurement range k specified by the selection signal Ss to the voltage detection circuit 3. The impedance calculation unit 43B calculates the value (Rr1_k, θr1_k) of the impedance of the reference circuit 8B by the same method as the impedance calculation units 43 and 43A according to Embodiments 1 and 2 based on the current detected by the current detection circuit 2 and the voltage detected by the voltage detection circuit 3, and stores it in the storage unit 46B as the reference measurement result 401_k (first condition) for the measurement range k. Similarly, in the second condition, when measuring the impedance of the reference circuit 8B according to the measurement range k, the impedance calculation unit 43B calculates the value (Rr2_k, θr2_k) of the impedance of the reference circuit 8B according to the measurement range k in the second condition, and stores it in the storage unit 46B as the reference measurement result 402_k (second condition) for the measurement range k.

[0217] In this way, the impedance calculation unit 43B measures the impedance of the reference circuit 8B for each of the measurement ranges 1 to n, and stores the reference measurement results (first condition) 401B_1 to 401B_n and the reference measurement results (second condition) 402B_1 to 402B_n in the storage unit 46B.

[0218] The correction coefficient update unit 42B calculates the first correction coefficient Gfix and the second correction coefficient θfix for each of the measurement ranges 1 to n by the same method as the correction coefficient update units 42 and 42 according to Embodiments 1 and 2, stores them in the storage unit 46 as the correction coefficient information 403_1 to 403_n, and updates the values of the correction coefficient information 403_1 to 403_n.

[0219] For example, when calculating correction coefficient information 403_k for measurement range k, the correction coefficient update unit 42B calculates the first correction coefficient Gfix_k and the second correction coefficient θfix_k using a method similar to that of embodiments 1 and 2 based on the difference between the reference measurement result 401B_k (Rr1_k, θr1_k) under the first condition in measurement range k and the reference measurement result 402B_k (Rr2_k, θr2_k) under the second condition in measurement range k, which are stored in the memory unit 46B, and stores the first correction coefficient Gfix_k and the second correction coefficient θfix_k in the memory unit 46B as correction coefficient information 403_k.

[0220] The corrector 44B is a functional unit that corrects the impedance value calculated by the impedance calculator 43B using correction coefficient information 403B_1 to 403B_n. The corrector 44B corrects the measured value (R, θ) of the impedance of the DUT 200 calculated by the impedance calculator 43B based on the correction coefficient information 403_1 to 403_m stored in the memory 46B, and stores the corrected DUT measurement result (second condition) 405B in the memory 46B.

[0221] For example, when correcting the measurement result in measurement range k, the correction unit 44B corrects the impedance measurement value (R_k, θ_k) of DUT200 in measurement range k based on the correction coefficient information 403_k (Gfix_k, θfix_k) corresponding to measurement range k using a method similar to that of the correction units 44, 44A of embodiments 1 and 2, and stores the corrected impedance measurement value (Rf_k, θf_k) of DUT200 in the memory unit 46B as the corrected DUT measurement result (second condition) 405B.

[0222] Similar to the memory units 46 and 46A according to the first and second embodiments, the memory unit 46B is a functional unit that stores the arithmetic expressions, various parameters, measurement results, and correction coefficients required to measure the electrical characteristics of the DUT and calculate the correction coefficients.

[0223] For example, as described above, the storage unit 46B stores reference measurement results (first condition) 401B_1 to 401B_n and reference measurement results (second condition) 402B_1 to 402B_n for each measurement range. The storage unit 46B also stores correction coefficient information 403B_1 to 403B_n including a first correction coefficient Gfix and a second correction coefficient θfix for each measurement range. The storage unit 46B also stores a DUT measurement result (second condition) 404B including a measured value (R, θ) of the impedance of the DUT 200 under the second condition, and a corrected DUT measurement result (second condition) 405B including a corrected measured value (Rf, θf) of the impedance of the DUT 200.

[0224] FIG. 12 is a flowchart showing the flow of impedance measurement by the measurement device 100B according to the third embodiment.

[0225] Here, it is assumed that a reference measurement result 401B_k (Rr1_k, θr1_k) for a predetermined measurement range k under a first condition (for example, initial adjustment) is stored in advance in the storage unit 46B of the data processing control circuit 4B, and that the DUT 200 is connected between the external terminals HC, HP and the external terminals LC, LP.

[0226] For example, when the user operates the operation unit 7 to specify a measurement range k and instruct measurement of the impedance of the DUT 200, first, similar to step S1 in the first embodiment described above, the data processing control circuit 4B controls the switch unit 5 to connect the internal terminals hci, hpi, lci, and lpi to the reference circuit 8 (step S1B).

[0227] Next, the data processing control circuit 4B controls the reference circuit 8B so that a voltage corresponding to the specified measurement range k is output from the reference circuit 8B (step S10B). Specifically, the instruction receiving unit 40 outputs a selection signal Ss indicating the measurement range k specified by the user, and the selection circuit 81 of the reference circuit 8B is enabled to output a voltage corresponding to the measurement range k specified by the selection signal Ss. For example, if the measurement range k is "100 mΩ," the selection circuit 81 is enabled to output the voltage of the terminal Pa2 (Xatt=0.1) of the network resistor Ratt.

[0228] Next, the data processing control circuit 4B measures the impedance (R, θ) of the reference circuit 8B (step S2B). Specifically, the instruction receiving unit 40B instructs the generation circuit 1 to output a voltage or a current, and instructs the impedance calculation unit 43B to measure the impedance in measurement range k. This causes the reference circuit 8B to output a voltage corresponding to measurement range k and input it to the voltage detection circuit 3. The impedance calculation unit 43B calculates the resistance component Rr2_k and phase θr2_k of the reference circuit 8B using the method described above based on the voltage signal output from the voltage detection circuit 3 and the current signal output from the current detection circuit 2, and stores the result as a reference measurement result 402B_k (second condition) in measurement range k in the storage unit 46B.

[0229] Next, the data processing control circuit 4B calculates correction coefficient information 403_k corresponding to the measurement range k (step S3B). Specifically, the correction coefficient update unit 42B calculates the first correction coefficient Gfix_k and the second correction coefficient θfix_k for the measurement range k by the above-mentioned method based on the reference measurement result 401B_k(Rr1_k, θr1_k) for the measurement range k under the first condition stored in the storage unit 46B and the reference measurement result 402B_k(Rr2_k, θr2_k) for the measurement range k under the second condition measured in step S2B, and stores the calculated correction coefficient information 403_k in the storage unit 46B.

[0230] In addition, if the correction coefficient information 403_k is already stored in the memory unit 46B, the correction coefficient update unit 42B rewrites the first correction coefficient Gfix_k and the second correction coefficient θfix_k stored in the memory unit 46B with the newly calculated first correction coefficient Gfix_k and second correction coefficient θfix_k.

[0231] Next, the data processing control circuit 4B controls the switch unit 5 to connect the internal terminals hci, hpi, lci, and lpi to the external terminals HC, HP, LC, and LP (step S4B). As a result, the internal terminals hci, hpi, lci, and lpi are connected to the DUT 200.

[0232] Next, the data processing control circuit 4B measures the phase value θ of the DUT 200 in the measurement range k (step S5B). Specifically, similar to step S2B, the instruction receiving unit 40B instructs the generation circuit 1 to output a voltage or a current, and instructs the impedance calculation unit 43A to measure the impedance in the measurement range k. The impedance calculation unit 43B calculates the resistance component value R_k and the phase value θ_k of the DUT 200 using the above-mentioned method based on the voltage signal output from the voltage detection circuit 3 and the current signal output from the current detection circuit 2, and stores them in the storage unit 46B as, for example, the DUT measurement result 404B (second condition).

[0233] Next, the data processing control circuit 4B corrects the measured impedance value (R_k, θ_k) of the DUT 200 in measurement range k measured in step S5B (step S6B). Specifically, the correction unit 44B calculates a corrected resistance component value Rf_k (=R_k×Gfix_k) by multiplying the resistance component value R_k of the DUT 200 in measurement range k measured in step S5B by the first correction coefficient Gfix_k for measurement range k stored in the storage unit 46B. The correction unit 44B also calculates a corrected phase value θf_k (=θ_k−θfix) by subtracting the second correction coefficient θfix_k for measurement range k stored in the storage unit 46B from the phase value θ_k of the DUT 200 measured in step S5B. The corrector 44B stores the calculated corrected resistance component value Rf_k and phase value θf_k as corrected DUT measurement result 405B_k in the memory 46B.

[0234] Next, the data processing control circuit 4B outputs the corrected DUT measurement result 405B_k (Rf_k, θf_k) to the output unit 6 as the measurement result of the phase angle of the impedance of the DUT 200 (step S7A). The output unit 6 displays, for example, information on the measurement result of the impedance of the DUT 200 in measurement range k (resistance component value Rf_k, phase θf_k, etc.) on a screen.

[0235] As described above, the reference circuit 8B according to the third embodiment includes a voltage divider circuit 80 including a first resistor Rm and a plurality of second resistors Ra1 to Ran (network resistors Ratt) connected in parallel with the first resistor Rm, and a selection circuit 81 that selects and outputs one voltage from the plurality of voltages output from the voltage divider circuit 80.

[0236] As described above, by appropriately setting the resistance value of the first resistor Rm and the resistance values (voltage division coefficients Xatt) of the plurality of second resistors Ra1 to Ran that make up the network resistor Ratt, it is possible to virtually realize a reference circuit (resistor) having a desired resistance value without using a highly stable resistor with a low resistance value such as a few mΩ.

[0237] Furthermore, as described above, the selection circuit 81 selects and outputs a voltage corresponding to the selection signal Ss that specifies the measurement range from among the multiple voltages output from the voltage divider circuit 80, thereby making it possible to correct measurement errors using a correction coefficient for each measurement range, and enabling impedance measurements with higher accuracy in each measurement range.

[0238] <<Extension of Embodiment>> The invention made by the inventor of the present application has been specifically described above based on an embodiment, but the present invention is not limited to this, and the combination of components may be changed between the respective embodiments, and the components of the invention may be modified in various ways within the scope of the gist of the invention.

[0239] For example, in the first and second embodiments, the measurement apparatus 100, 100A measures the impedance of the DUT 200 by the four-terminal method. However, the present invention is not limited to this, and the impedance of the DUT 200 may be measured by the two-terminal method.

[0240] FIG. 13 is a diagram showing the configuration of a measurement apparatus 100C capable of measuring impedance by the two-terminal method.

[0241] 13, the measurement device 100C has, for example, an external terminal H as a first external terminal, an external terminal L as a second external terminal, an internal terminal hi as a first internal terminal, and an internal terminal li as a second internal terminal. The reference circuit 8C also has, for example, a terminal hr as a high-side terminal and a terminal lr as a low-side terminal. The reference circuit 8C may have the same internal configuration as, for example, the reference circuits 8 and 8A.

[0242] The generating circuit 1 applies a voltage or current between the internal terminals hi and li. The current detecting circuit 2 detects the current flowing between the internal terminals hi and li. For example, the current detecting circuit 2 is connected in series between the positive output terminal of the generating circuit 1 and the internal terminal hi, or between the negative output terminal of the generating circuit 1 and the internal terminal li. FIG. 13 shows, as an example, a case where the current detecting circuit 2 is connected in series between the negative output terminal of the generating circuit 1 and the internal terminal li.

[0243] The positive input terminal of the voltage detection circuit 3 is connected to the internal terminal hi, and the negative input terminal of the voltage detection circuit 3 is connected to the internal terminal li. The voltage detection circuit 3 detects the voltage between the internal terminals hi and li and outputs it.

[0244] The switch unit 5C switches the connection destination of the internal terminals hi, hi between the external terminal H and one terminal hr of the reference circuit 8C, and switches the connection destination of the internal terminal li between the external terminal L and the other terminal lr of the reference circuit 8C in response to the signal Sc from the data processing control circuit 4. The switches 51C, 53C constituting the switch unit 5C are each formed of a double-throw switch element, for example, similar to the above-mentioned switch 51.

[0245] In the measuring device 100C, the data processing control device 4, the output unit 6, and the operation unit 7 are the same as those in the first and second embodiments.

[0246] According to the above-described measuring device 100C, even when measuring impedance using the two-terminal method, a user can measure the impedance of the reference circuit 8C using the measuring device 100C under various conditions and compare the measurement results, thereby easily knowing the measurement error caused by the measuring device 100C and enabling more accurate impedance measurement.

[0247] Furthermore, in the second embodiment, the data processing control circuit 4A corrects the measured impedance value using the first correction coefficient Gfix and the second correction coefficient θfix, but this is not limiting. For example, the data processing control circuit 4A may only correct the measured impedance phase angle using the second correction coefficient θfix. Similarly, the data processing control circuit 4B according to the third embodiment may correct the measured impedance value using only either the first correction coefficient Gfix or the second correction coefficient θfix.

[0248] Furthermore, in the third embodiment, the case where measurement device 100B has reference circuit 8B built in has been described as an example, but this is not limiting, and reference circuit 8B may be realized as a "standard resistor" separate from measurement device 100B. In this case, reference circuit 8B as a standard resistor is a single device including high-side input terminal hcr, high-side output terminal hpr, low-side input terminal lcr, low-side output terminal lpr, voltage divider circuit 80, and selection circuit 81.

[0249] According to this, by connecting the high-side input terminal hcr, high-side output terminal hpr, low-side input terminal lcr, and low-side output terminal lpr of the reference circuit 8B as a standard resistor to the external terminals HC, HP, LC, and LP of an existing measuring device that does not have a built-in reference circuit 8B, it becomes possible to correct measurement errors using the reference circuit 8B (standard resistor) even in the existing measuring device.

[0250] In the first to third embodiments, the measurement apparatuses 100, 100A, 100B, and 100C each include a current detection circuit 2, but this is not limiting. For example, if the value of the current flowing through the measurement target (DUT or reference circuit 8, 8A, or 8B) is known, such as when the generation circuit 1 outputs a constant current, the current detection circuit 2 may not be provided. In this case, the arithmetic circuits 4, 4A, and 4B may calculate the impedance using the current value stored in advance in the memory unit 46, 46A, or the like, using the method described above.

[0251] Furthermore, the above-described flowcharts are merely examples for explaining the operation, and are not intended to be limiting. That is, the steps shown in each diagram of the flowchart are specific examples, and the present invention is not limited to these flows. For example, the order of some processes may be changed, other processes may be inserted between processes, or some processes may be performed in parallel. [Explanation of symbols]

[0252] 1...Generation circuit, 2...Current detection circuit, 3...Voltage detection circuit, 4...Data processing control circuit, 5...Switch unit, 6...Output unit, 7...Operation unit, 8, 8A, 8B...Reference circuit, 40, 40B...Instruction reception unit, 41...Switch control unit, 42, 42A, 42B...Correction coefficient update unit, 43, 43A, 43B...Impedance calculation unit, 44, 44A, 44B...Correction unit, 45...Measurement result output unit, 51 to 54...Switch, 80...Voltage divider circuit, 81...Selection circuit, 82...Buffer, 401, 401A, 401B_1 to 401_n...Reference measurement result (first condition), 402, 402A, 402B_1 to 403B_n...Reference measurement result (second condition), 403, 403A, 403B_1 to 403B_n...Correction coefficient information information, 404, 404A, 404B...DUT measurement results, 405, 405A, 405B...DUT measurement results after correction, HC...high-side external application terminal, LC...low-side external application terminal, HP...high-side external detection terminal, LP...low-side external detection terminal, hci...high-side internal application terminal, hpi...high-side internal detection terminal, lci...low-side internal application terminal, lpi...low-side internal detection terminal, hcr...high-side input terminal, hpr...high-side output terminal, lcr...low-side input terminal, lpr...low-side output terminal, Rref...reference resistor, Rm...first resistor, Ra1 to Ran...second resistor, Ratt...network resistor, Sb, Sc...signal, Ss...selection signal, So...measurement result.

Claims

1. a first external terminal for connecting one terminal of a test object and a second external terminal for connecting the other terminal of the test object; a first internal terminal and a second internal terminal; a generating circuit that applies a voltage or a current between the first internal terminal and the second internal terminal; a voltage detection circuit that detects a voltage between the first internal terminal and the second internal terminal; a data processing control circuit that measures an impedance between the first internal terminal and the second internal terminal based on the voltage detected by the voltage detection circuit and the current flowing between the first internal terminal and the second internal terminal; a reference circuit having two terminals and a predetermined impedance; a switch unit that switches a connection destination of the first internal terminal between the first external terminal and one terminal of the reference circuit, and that switches a connection destination of the second internal terminal between the second external terminal and the other terminal of the reference circuit. Measuring equipment.

2. 2. The measuring device according to claim 1, The data processing control circuit corrects a measurement result of the impedance between the first internal terminal and the second internal terminal when the first external terminal and the first internal terminal are connected by the switch unit and the second external terminal and the second internal terminal are connected by the switch unit under the second condition, based on an error between a measurement result of the impedance of the reference circuit when one terminal of the reference circuit is connected to the first internal terminal by the switch unit and the other terminal of the reference circuit is connected to the second internal terminal under a first condition, and a measurement result of the impedance of the reference circuit when one terminal of the reference circuit is connected to the first internal terminal by the switch unit and the other terminal of the reference circuit is connected to the second internal terminal under a second condition different from the first condition. Measuring equipment.

3. 3. The measuring device according to claim 2, The data processing control circuit corrects the value of the resistance component of the impedance of the test device measured under the second condition based on an error between the value of the resistance component of the impedance of the reference circuit measured under the first condition and the value of the resistance component of the impedance of the reference circuit measured under the second condition. Measuring equipment.

4. 4. The measuring device according to claim 3, The data processing control circuit calculates a first correction coefficient based on a ratio between the value of the resistance component of the impedance of the reference circuit measured under the first condition and the value of the resistance component of the impedance of the reference circuit measured under the second condition, and corrects the value of the resistance component of the impedance of the test object measured under the second condition using the first correction coefficient. Measuring equipment.

5. 3. The measuring device according to claim 2, The data processing control circuit corrects the value of the phase angle of the impedance of the test device measured under the second condition based on an error between the value of the phase angle of the impedance of the reference circuit measured under the first condition and the value of the phase angle of the impedance of the reference circuit measured under the second condition. Measuring equipment.

6. 6. The measuring device according to claim 5, The data processing control circuit calculates a second correction coefficient based on a difference between a value of a phase angle of the impedance of the reference circuit measured under the first condition and a value of a phase angle of the impedance of the reference circuit measured under the second condition, and corrects the value of the phase angle of the impedance of the test object measured under the second condition using the second correction coefficient. Measuring equipment.

7. 3. The measuring device according to claim 2, The data processing control circuit includes: an instruction receiving unit that receives an instruction to the measurement device; a storage unit that stores the impedance value of the reference circuit measured under the first condition and correction coefficient information for correcting the impedance value of the test device measured under the second condition; a switch control unit that controls the switch unit; an impedance calculation unit that calculates a value of impedance between the first internal terminal and the second internal terminal; a correction unit that corrects the impedance value calculated by the impedance calculation unit based on the correction coefficient information; a measurement result output unit that outputs the impedance value corrected by the correction unit as a measurement result; a correction coefficient update unit that updates the correction coefficient information, When the instruction receiving unit receives a predetermined instruction, the switch unit connects one terminal of the reference circuit to the first internal terminal and connects the other terminal of the reference circuit to the second internal terminal, the impedance calculation unit calculates an impedance value between the first internal terminal and the second internal terminal and stores the calculated value in the storage unit as an impedance value of the reference circuit measured under the second condition, and the correction coefficient update unit updates the correction coefficient information based on the impedance value of the reference circuit measured under the first condition and the impedance value of the reference circuit measured under the second condition, which are stored in the storage unit. Measuring equipment.

8. 8. The measuring device according to claim 1, The reference circuit includes a resistor. Measuring equipment.

9. 2. The measuring device according to claim 1, the first internal terminal includes a high-side internal application terminal to which a voltage or a current is applied from the generation circuit, and a high-side internal detection terminal connected to the voltage detection circuit; the second internal terminal includes a low-side internal application terminal to which a voltage or a current is applied from the generation circuit, and a low-side internal detection terminal connected to the voltage detection circuit; the first external terminal includes a high-side external application terminal and a high-side external detection terminal; the second external terminal includes a low-side external application terminal and a low-side external detection terminal; The reference circuit a high-side input terminal and a high-side output terminal as one terminal of the reference circuit, and a low-side input terminal and a low-side output terminal as the other terminal of the reference circuit; a first resistor connected between the high-side input terminal and the low-side input terminal; and a plurality of second resistors connected in series between the high-side input terminal and the low-side input terminal; a selection circuit that receives a voltage between the high-side input terminal and the low-side input terminal and a plurality of voltages divided by the plurality of second resistors, selects one of the input voltages, and outputs the selected voltage between the high-side output terminal and the low-side output terminal. The switch unit switches a connection destination of the high-side internal voltage terminal between the high-side external voltage terminal and the high-side input terminal of the reference circuit, switches a connection destination of the low-side internal voltage terminal between the low-side external voltage terminal and the low-side input terminal of the reference circuit, switches a connection destination of the high-side internal detection terminal between the high-side external detection terminal and the high-side output terminal of the reference circuit, and switches a connection destination of the low-side internal detection terminal between the low-side external detection terminal and the low-side output terminal of the reference circuit. Measuring equipment.

10. 10. The measuring device according to claim 9, A selection signal that specifies a measurement range is input to the selection circuit, The selection circuit selects and outputs a voltage corresponding to the measurement range designated by the selection signal from among the input voltages. Measuring equipment.

11. 11. The measuring device according to claim 9 or 10, The plurality of second resistors are a network resistor. Measuring equipment.

12. a high-side input terminal and a high-side output terminal; a low-side input terminal and a low-side output terminal; a first resistor connected between the high-side input terminal and the low-side input terminal; a plurality of second resistors connected in series between the high-side input terminal and the low-side input terminal; a selection circuit that receives a voltage between the high-side input terminal and the low-side input terminal and a plurality of voltages divided by the plurality of second resistors, selects one of the input voltages, and outputs the selected voltage between the high-side output terminal and the low-side output terminal. Standard resistor.

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