WO2023249094A1

WO2023249094A1 - Measurement device and standard resistor

Info

Publication number: WO2023249094A1
Application number: PCT/JP2023/023200
Authority: WO
Inventors: 一暁羽田; 直也北村
Original assignee: 日置電機株式会社
Priority date: 2022-06-24
Filing date: 2023-06-22
Publication date: 2023-12-28

Abstract

The present invention makes it possible to easily know an error of measurement by this measurement device.　A measurement 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 voltage and current between the first internal terminals (hci, hpi) and the second internal terminals (lci, lpi) upon application of the voltage or the current between the first internal terminals (hci, hpi) and the second internal terminals (lci, lpi); a reference circuit (8) that has a prescribed impedance; and a switch (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).

Description

Measuring equipment and standard resistors

The present invention relates to a measuring device and a standard resistor, and for example, to a measuring device that measures the electrical characteristics of an object to be measured.

Measuring devices such as LCR meters, resistance meters, and battery testers that measure electrical characteristics such as impedance of an object to be measured (hereinafter also referred to as "DUT: Device Under Test") are known (see Patent Document 1). ).

Japanese Patent Application Publication No. 2020-76600

The measurement device described above includes 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. It consists of The characteristics of these internal circuits are influenced by the characteristics of electronic components such as a reference voltage source, reference resistor, gain setting resistor, transistor, and capacitor that constitute the circuit.

It is generally known that the characteristics of electronic components change depending on temperature and aging. When the characteristics of electronic components change due to temperature and age, the characteristics of the various internal circuits that make up the measurement device change, causing an error between the true value of the DUT's impedance and the measurement result of the DUT's impedance by the measurement device. may occur.

In order to achieve more accurate measurements, it is important to know the measurement errors made by the measuring device. However, many conventional measuring devices do not have a function that allows the user to easily know the error of the measuring device itself.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make it possible to easily know errors in measurement by a measuring device.

A measuring device according to a typical embodiment of the present invention includes 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, a second internal terminal, a generation circuit that applies a voltage or current between the first internal terminal and the second internal terminal, and 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 based on the voltage detected by the voltage detection circuit and the current flowing between the first internal terminal and the second internal terminal. and the second internal terminal; a reference circuit having two terminals and having a predetermined impedance; and a reference circuit that connects the first internal terminal to the first external terminal. and one terminal of the reference circuit, and a switch unit that switches the connection destination of the second internal terminal between the second external terminal and the other terminal of the reference circuit, In the data processing control circuit, under a first condition, one terminal of the reference circuit and the first internal terminal are connected by the switch section, and the other terminal of the reference circuit is connected to the second internal terminal. The impedance of the reference circuit is measured under a second condition different from the first condition, in which one terminal of the reference circuit and the first internal terminal are connected by the switch unit, and the impedance of the reference circuit is Measure the impedance of the reference circuit when the other terminal of the circuit and the second internal terminal are connected, and compare the impedance measurement result of the reference circuit under the first condition and the reference circuit under the second condition. Based on the error with the measurement result of the impedance of the circuit, under the second condition, the first external terminal and the first internal terminal are connected by the switch section, and the second external terminal and the second internal terminal are connected. The method is characterized in that a measurement result of impedance between the first internal terminal and the second internal terminal when the terminals are connected is corrected.

According to the measuring device according to the present invention, it is possible to easily know the error in measurement by the measuring device.

1 is a diagram showing the configuration of a measuring device according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating a connection example of each switch configuring the switch section. FIG. 3 is a diagram illustrating a connection example of each switch configuring the switch section. 1 is a diagram showing the configuration of a data processing control circuit according to Embodiment 1. FIG. 5 is a flowchart showing the flow of impedance measurement by the measuring device according to the first embodiment. FIG. 3 is a diagram showing the configuration of a measuring device according to a second embodiment. 7 is a diagram showing an example of a reference circuit according to Embodiment 2. FIG. 3 is a diagram showing the configuration of a data processing control circuit according to a second embodiment. FIG. 7 is a flowchart showing the flow of impedance measurement by the measuring device according to Embodiment 2. FIG. 3 is a diagram showing the configuration of a measuring device according to Embodiment 3. FIG. FIG. 7 is a diagram showing an example of a reference circuit according to Embodiment 3; FIG. 7 is a diagram showing the configuration of a data processing control circuit according to a third embodiment. 12 is a flowchart showing the flow of impedance measurement by the measuring device according to Embodiment 3. 1 is a diagram showing the configuration of a measuring device capable of measuring impedance using a two-terminal method. FIG. 7 is a diagram showing another example of a reference circuit.

1. Overview of Embodiments First, an overview of typical embodiments of the invention disclosed in this application will be described. In the following description, as an example, reference numerals on the drawings corresponding to constituent elements of the invention are written in parentheses.

[1] The measuring device (100, 100A, 100B, 100C) according to a typical embodiment of the present invention has a first external terminal (HC, HP) for connecting one terminal of the test object (200). , H), and a second external terminal (LC, LP, L) for connecting the other terminal of the test object, a first internal terminal (hci, hpi, hi) and a second internal terminal (lci, lpi, li), a generating circuit (1) that applies a voltage or current between the first internal terminal and the second internal terminal, and a generating circuit (1) that applies a voltage or current between the first internal terminal and the second internal terminal. a voltage detection circuit (3) that detects a voltage; and a voltage detection circuit (3) that detects a voltage 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 data processing control circuit (4, 4A, 4B) that measures impedance with the second internal terminal; a reference circuit (8, 8A, 8B, 8C) having two terminals and a predetermined impedance; , the connection destination of the first internal terminal is switched between the first external terminal and one terminal of the reference circuit, and the connection destination of the second internal terminal is switched between the second external terminal and the other terminal of the reference circuit. a switch unit (5, 5C) for switching between one terminal of the reference circuit and the first internal terminal by the switch unit under a first condition. and the measurement result of the impedance of the reference circuit when the other terminal of the reference circuit and the second internal terminal are connected (see FIG. 2A), and under a second condition different from the first condition. , when one terminal of the reference circuit and the first internal terminal are connected by the switch unit, and the other terminal of the reference circuit and the second internal terminal are connected (see FIG. 2A). A correction coefficient is calculated based on the error with the impedance measurement result of the reference circuit, and under the second condition, the first external terminal and the first internal terminal are connected by the switch unit, and the second external The measurement result of the impedance between the first internal terminal and the second internal terminal when the terminal and the second internal terminal are connected (see FIG. 2B) is corrected based on the correction coefficient. shall be.

[2] In the measuring device according to [1] above, the generation circuit transmits an AC signal based on a reference signal (Sb) having a constant frequency and a constant amplitude to the first internal terminal and the second internal terminal. and the data processing control circuit detects the amplitude (|V|) of the voltage signal detected by the voltage detection circuit and the voltage phase difference between the reference signal and the voltage signal by synchronous detection. (θv), the amplitude (|I|) of the current signal flowing between the first internal terminal and the second internal terminal, and the current phase difference (θi) between the reference signal and the current signal. and the impedance between the first internal terminal and the second internal terminal based on the amplitude of the voltage signal, the voltage phase difference, the amplitude of the current signal, and the current phase difference, respectively. the value of the resistance component (R=|V|/|I|×cosθ) and the impedance between the first internal terminal and the second internal terminal, which is the difference between the voltage phase difference and the current phase difference. The value of the phase angle (θ=θv−θi) may be calculated.

[3] In the measuring device (100, 100A, 100B, 100C) described in [2] above, the data processing control circuit (4, 4A, 4B) is configured to perform the measurement under the first condition. 8A, 8B, 8C) and the value (Rr2) of the impedance of the reference circuit measured under the second condition. The value of the resistance component of the measured impedance of the test object may be corrected.

[4] In the measuring device according to [3] above, the data processing control circuit includes, as the correction coefficient, a value (Rr1) of the resistance component of the impedance of the reference circuit measured under the first condition; A first correction coefficient (Gfix) is calculated based on the ratio of the impedance of the reference circuit measured under the two conditions to the value of the resistance component (Rr2), and using the first correction coefficient, the measurement is performed under the second condition. The value of the resistance component of the impedance of the test object may be corrected.

[5] In the measuring device (100A, 100B, 100C) according to any one of [2] to [4] above, the data processing control circuit (4A, 4B) is configured to perform the measurement under the first condition. The test measured under the second condition based on the error between the value of the phase angle of the impedance of the reference circuit (θr1) and the value of the phase angle of the impedance of the reference circuit (θr2) measured under the second condition. The value of the phase angle of the impedance of the object may be corrected.

[6] In the measuring device according to [5] above, the data processing control circuit includes, as the correction coefficient, a phase angle value (θr1) of the impedance of the reference circuit measured under the first condition; A second correction coefficient (θfix) is calculated based on the difference between the phase angle value (θr2) of the impedance of the reference circuit measured under the two conditions, and using the second correction coefficient, the impedance of the reference circuit measured under the second condition is calculated. The value of the phase angle of the impedance of the test object may be corrected.

[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 that receives instructions to the measuring device. (40, 40B), the impedance value (Rr1, θr1) of the reference circuit measured under the first condition, and correction coefficient information (Gfix, θfix) including the correction coefficient ( 46, 46A, 46B), a switch control unit (41) that controls the switch unit, and an impedance calculation unit (43, 43A) that calculates the value of impedance between the first internal terminal and the second internal terminal. , 43B), 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 correction unit (44, 44A, 44B) that corrects the impedance value corrected by the correction unit as a measurement result. and a correction coefficient updating unit (42, 42A, 42B) that updates the correction coefficient information, and 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, and the impedance calculation unit connects the first internal terminal to the second internal terminal. Calculating the impedance value between the first internal terminal and the second internal terminal and storing it in the storage unit as the impedance value (Rr2, θr2) of the reference circuit measured under the second condition; The correction coefficient updating unit updates the impedance values (Rr1, θr1) of the reference circuit measured under the first condition, which are stored in the storage unit, and the impedance values (Rr1, θr1) of the reference circuit measured under the second condition. The correction coefficient information (Gfix, θfix) may be updated based on the impedance value (Rr2, θr2).

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

[9] In the measuring device (100B) according to [1] above, the first internal terminal is connected to a high side internal application terminal (hci) to which a voltage or current is applied from the generation circuit, and to the voltage detection circuit. a high-side internal detection terminal (hpi) connected to the second internal terminal, and the second internal terminal is connected to a low-side internal application terminal (lci) to which a voltage or current is applied from the generation circuit and the voltage detection circuit. the first external terminal includes a high side external application terminal (HC) and a high side external detection terminal (HP); the second external terminal includes a low side internal detection terminal (lpi); The reference circuit (8B) includes a low side external application terminal (LC) and a low side external detection terminal (LP), and the reference circuit (8B) has a high side input terminal (hcr) as one terminal of the reference circuit and a high side output terminal. (hpr), a low side input terminal (lcr) and a low side output terminal (lpr) as the other terminal of the reference circuit, and a first resistor connected between the high side input terminal and the low side input terminal. (Rm), a plurality of second resistors (Ra0 to Ran) connected in series between the high side input terminal and the low side input terminal, and between the high side input terminal and the low side input terminal. and a plurality of voltages divided by the plurality of second resistors, select any one of the input voltages, and output the voltage to the high-side output terminal and the low-side output terminal. a selection circuit (81) that outputs an output between the high side internal application terminal (hci) and the high side external application terminal (HC) and the high side of the reference circuit. switching the 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; Switching the 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 connecting the low side internal detection terminal (lpi). The terminal may be switched between the low side external detection terminal (LP) and the low side output terminal (lpr) of the reference circuit.

[10] In the measuring device according to [9] above, the reference circuit further includes a third resistor (Rc) connected in parallel with at least one resistor among the plurality of second resistors. You can stay there.

[11] In the measuring device (100B) according to [9] or [10] above, a selection signal (Ss) specifying a measurement range is input to the selection circuit, and the selection circuit Among them, a voltage corresponding to the measurement range designated by the selection signal may be selected and output.

[12] In the measuring device (100B) according to any one of [9] to [11] above, the plurality of second resistors (Ra1 to Ran) may be network resistors.

[13] The standard resistor (8B) according to the typical embodiment of the present invention has a high side input terminal (hcr) and a high side output terminal (hpr), and 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, and a plurality of resistors (Rm) connected in series between the high-side input terminal and the low-side input terminal. a second resistor (Ra0 to Ran), a third resistor (Rc) connected in parallel with at least one resistor among the plurality of second resistors, and a third resistor (Rc) connected to the high side input terminal and the low side input terminal. input the voltage between the terminal and the plurality of voltages divided by the plurality of second resistors, select any one of the input voltages, and select the voltage between the high side output terminal and the plurality of voltages divided by the plurality of second resistors. It is characterized by including a selection circuit (81) that outputs between the low side output terminal and the low side output terminal.

2. Specific Examples of Embodiments Hereinafter, specific examples of embodiments of the present invention will be described with reference to the drawings. In addition, in the following description, the same reference numerals are given to the same component in each embodiment, and repeated description is omitted. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, etc. may differ from reality. Drawings may also include portions that differ in dimensional relationships and ratios.

≪Embodiment 1≫
FIG. 1 is a diagram showing the configuration of a measuring device 100 according to the first embodiment.

A measuring device 100 shown in FIG. 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, a battery tester for measuring battery characteristics, and the like. Note that the measuring device 100 may be any device that can measure electrical characteristics such as impedance of the DUT, and is not limited to the above-mentioned example.

In addition to the function of measuring the electrical characteristics of the DUT, the measuring device 100 has a function of correcting measurement errors caused by changes in circuit characteristics within the measuring device 100 due to temperature or aging.

The measuring device 100 includes, for example, external terminals, internal terminals, a generation circuit 1, a current detection circuit 2, a voltage detection circuit 3, a data processing control circuit 4, a switch section 5, It has an output section 6, an operation section 7, and a reference circuit (REF) 8.

The external terminal is a terminal for connecting the DUT. The measuring device 100 has, as 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 the measuring device 100, one terminal of the DUT is connected to the high side external application terminal HC and the high side external detection terminal HP, and the low side external detection terminal LP and the low side external application terminal LC are connected to one terminal of the DUT. The other terminal of the DUT is connected to.
In the following description, the high-side external application terminal HC, high-side external detection terminal HP, low-side external detection terminal LP, and low-side external application terminal LC are simply expressed as "external terminals HC, HP, LC, LP." There are cases where

The internal terminal is a terminal connected to the circuits (generating circuit 1, current detecting circuit 2, and voltage detecting circuit 3) within the measuring device 100. The measuring device 100 has, as 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.

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

In the following description, the high-side internal application terminal hci, high-side internal detection terminal hpi, low-side internal application terminal lci, and low-side internal detection terminal lpi are simply expressed as "internal terminals hci, hpi, lci, lpi." There are cases where

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

The generating circuit 1 is a circuit that generates a voltage or current to be applied to an object to be measured in order to measure impedance. Generation circuit 1 applies a voltage or current between internal terminal hci and internal terminal 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, as an example, the generation circuit 1 will be described as a constant current generation circuit.

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

The constant current signal output from the generating circuit 1 may be an alternating current signal or a direct current signal, and can be changed depending on the purpose of the measuring device 100, for example.

The current detection circuit 2 is a circuit that detects the current flowing between the internal terminal hci and the internal terminal lci. For example, the current detection circuit 2 is connected in series between the positive output terminal of the generating circuit 1 and the internal terminal hci, or between the negative output terminal of the generating circuit 1 and the internal terminal lci. FIG. 1 shows, as an example, a case where the current detection circuit 2 is connected in series between the negative output terminal of the generation circuit 1 and the internal terminal lci.

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

The voltage detection circuit 3 is a circuit that 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. Voltage detection circuit 3 detects and outputs the voltage between internal terminals hpi and lpi. The voltage detection circuit 3 includes, for example, an operational amplifier, and amplifies the detected voltage between the external terminal HP and the external terminal LP with the operational amplifier and outputs it as a voltage signal.

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

The output unit 6 is a device that outputs various information such as measurement conditions and measurement results in 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 display. For example, when measurement of the impedance of the DUT is instructed by a user's input to the operation unit 7, the output unit 6 displays information such as the measurement result of the DUT impedance calculated by the data processing control circuit 4 on the screen. indicate.

Note that the output unit 6 may be a display device equipped with a touch panel that implements some of the functions of the operation unit 7. Further, the output unit 6 may include a communication circuit or the like that outputs data such as measurement results to the outside by wire or wirelessly.

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

The data processing control circuit 4 is a circuit that centrally controls each functional section within the measuring device 100. The data processing control circuit 4 is, for example, an MCU (Micro Controller Unit) having a processor such as a CPU, a storage device such as a ROM, RAM, or a flash memory, and various peripheral circuits such as a timer or an A/D conversion circuit, or A program processing device such as an FPGA (Field-Programmable Gate Array) can be exemplified.

The data processing control circuit 4 controls each functional unit in the measuring device 100 in accordance with the signal Sd from the operation unit 7, thereby calculating, for example, the measured value of the impedance of the DUT 200 or the reference circuit 8, as will be described later. The correction coefficients are updated and the measured values are corrected using the correction coefficients. Details of the data processing control circuit 4 will be described later.

The reference circuit 8 is a circuit whose impedance can be measured by connecting it to the generation circuit 1 and the voltage detection circuit 3 in the same way as the DUT. The reference circuit 8 can be used to calculate and correct measurement errors by the measuring device 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.

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 are simply expressed as "terminals hcr, hpr, lcr, lpr." There are cases.

The reference circuit 8 includes, for example, a resistor. In the first embodiment, as an example, it is assumed that 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."

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

The reference resistor Rref is preferably a resistor with high precision and high reliability. For example, it is preferable to use a precision resistor as the reference resistor Rref, which has a temperature coefficient of resistance of ±5 ppm/° C. or less and a long-term stability (change over time) of resistance value of ±100 ppm/year or less. Note that the above numerical values are just an example, and can be changed as appropriate depending on the specifications required of the measuring device 100. Further, the resistance value of the reference resistor Rref may be appropriately set according to the measurable range of impedance by the measuring device 100.

The switch section 5 is a functional section 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, for example, a double-throw switch element. Examples of the switch element include components such as semiconductor switches (for example, transistors) and relays (for example, mechanical relays) whose connection destinations can be switched in response to electrical signals.

The switch unit 5 switches the connection destinations of the internal terminals hci, hpi between the external terminal HC and one terminal hcr, hpr of the reference circuit 8, and switches the connection destinations of the internal terminals lci, lpi between the external terminal LC and the reference circuit. 8 and the other terminals lcr and lpr. The switch section 5 switches the connection destinations of the internal terminals hci, hpi, lci, and lpi according to the signal Sc from the data processing control circuit 4.

FIGS. 2A and 2B are diagrams showing connection examples of the switches 51 to 54 that make up the switch section 5.

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

When measuring the impedance of the reference circuit 8, the switch unit 5 sets the switches 51 to 54 to the state shown in FIG. 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, and the switch 53 connects the internal terminal lci to the terminal lcr of the reference circuit 8. The switch 54 connects the internal terminal lpi to the terminal lpr of the reference circuit 8. Thereby, the internal terminals hci, hpi, lci, and lpi are connected to the reference resistor Rref as the reference circuit 8.

On the other hand, when measuring the impedance of the DUT 200, the switch unit 5 sets the switches 51 to 54 to the state shown in FIG. 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 hpi to the external terminal HP. Connect lpi to external terminal LP. As a result, the internal terminals hci, hpi, lci, and lpi are connected to the DUT 200.

Here, the data processing control circuit 4 will be explained in detail.

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

Specifically, under the first condition, the data processing control circuit 4 connects one terminal hcr, hpr of the reference circuit 8 to the internal terminals hci, hpi by the switch unit 5, and connects the other terminal lcr of the reference circuit 8 to the internal terminals hci, hpi. , lpr and the internal terminals lci, lpi are connected (see FIG. 2A), the impedance measurement result of the reference circuit 8 is obtained. Further, in the data processing control circuit 4, under a second condition different from the first condition, one terminal hcr, hpr of the reference circuit is connected to the internal terminal hci, hpi by the switch section 5, and the other terminal of the reference circuit 8 is connected. The impedance measurement result of the reference circuit 8 when the terminals lcr, lpr and the internal terminals lci, lpi are connected (see FIG. 2A) is obtained. Further, in the data processing control circuit 4, under the second condition, the external terminals HC and HP are connected to the internal terminals hci and hpi, and the external terminals LC and LP are connected to the internal terminals lci and lpi. The impedance measurement results between the internal terminals hci, hpi and the internal terminals lci, lpi at the time (see FIG. 2B) are obtained.

The data processing control circuit 4 uses the switch unit 5 to connect an external terminal under the second condition based on the error between the impedance measurement result of the reference circuit 8 under the first condition and the impedance measurement result of the reference circuit 8 under the second condition. The impedance between internal terminals hci, hpi and internal terminals lci, lpi when HC, HP and internal terminals hci, hpi are connected, and external terminals LC, LP are connected to internal terminals lci, lpi. Correct the measurement results.

More specifically, the data processing control circuit 4 determines 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. The value of the resistance component of the impedance of the DUT 200 measured under the second condition is corrected based on the error.

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 determines 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 resistance component Rr2 of the impedance of the reference circuit 8 measured under the second condition. A first correction coefficient Gfix based on the first correction coefficient Gfix is calculated.

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 multiplies 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. Correct R.

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

As shown in FIG. 3, the data processing control circuit 4 includes, as functional blocks for realizing the above-mentioned functions, an instruction receiving section 40, a switch control section 41, a correction coefficient updating section 42, an impedance calculation section 43, a correction It has a measurement result output section 44, a measurement result output section 45, and a storage section 46. These functional blocks are realized, for example, in a program processing unit (MCU) as the data processing control circuit 4, by a processor executing various arithmetic operations according to programs stored in a storage device and controlling peripheral circuits. Ru. Note that some or all of the above functional blocks may be realized by a dedicated logic circuit.

The instruction receiving unit 40 is a functional unit that receives instructions to the measuring device 100. The instruction receiving unit 40 receives a signal Sd from the operation unit 7 and instructs other functional unit locks and the like to execute processing according to the signal Sd.

For example, when the user instructs execution of the impedance measurement of the DUT 200 by operating the operation unit 7, the instruction receiving unit 40 sends the switch control unit 41, the correction The coefficient updating unit 42, the impedance calculating unit 43, and the like are instructed to execute processing for measuring the impedance of the DUT 200.

Furthermore, for example, the user may operate the operation unit 7 to instruct the update of the correction coefficient. 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 for updating the correction coefficient.

Furthermore, for example, the user may operate the operation unit 7 to instruct measurement of 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 calculation unit 43, etc. instructs execution of processing to measure. In this case, information on the impedance measurement result of the reference circuit 8 may be displayed on the screen by the output unit 6, or may be output as measurement data to an external device. The output unit 6 also outputs not only information on the latest impedance measurement results of the reference circuit 8 but also information on previously measured impedance measurement results of the reference circuit 8 under the first condition described below. The measurement results) may also be output (displayed).

The storage unit 46 is a functional unit that stores arithmetic expressions, various parameters, measurement results, correction coefficients, etc. necessary for measuring electrical characteristics of the DUT, calculating correction coefficients, etc.

For example, the storage unit 46 stores a reference measurement result (first condition) 401 including the value Rr1 of the reference resistance Rref measured under the first condition, and a value Rr2 of the reference resistance Rref measured under the second condition, which will be described later. Reference measurement result (second condition) 402 including, correction coefficient information 403 including first correction coefficient Gfix, DUT measurement result (second condition) 404 including value R of the resistance component of 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 is stored. The storage unit 46 also stores various calculation formulas necessary for impedance measurement, such as calculation formulas for calculating impedance values, calculation formulas for calculating correction coefficients, and calculation formulas for correcting measurement results. remembered.

The switch control section 41 is a functional section for controlling the switch section 5.
The switch control unit 41 switches the connection destinations of the internal terminals hci, hpi, lci, and lpi by controlling the switch unit 5 according to an instruction from the instruction receiving unit 40, for example.

The impedance calculation unit 43 is a functional unit that calculates the value of impedance between the internal terminal hpi and the internal terminal lpi. The impedance calculation unit 43 calculates an impedance value between the internal terminal hpi and the internal terminal 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. Calculate.

Specifically, as described above, the calculation formula for calculating the value of the resistance component of impedance is stored in the storage unit 46, and the impedance calculation unit 43 uses the calculation formula stored in the storage unit 46. is used to calculate the value of the resistance component of impedance.

For example, when the DUT 200 is connected to the internal terminals hci, hpi, lci, and lpi, a current is applied from the generation circuit 1 to the DUT 200, and the voltage detected by the voltage detection circuit 3 is V, and the voltage detected by the current detection circuit 2 is When the current input is I, the impedance calculation unit 43 calculates the value R of the resistance component of the impedance of the DUT 200 using the calculation formula “R=V/I” stored in the storage unit 46, and It is stored in the storage unit 46 as a measurement result 404.

Note that the arithmetic expression for calculating impedance is not limited to the above example, and can be changed as appropriate depending on the specifications required for the measuring device 100. For example, when performing the initial adjustment described later, a correction coefficient etc. obtained by the initial adjustment may be included in the above equation.

The correction coefficient update unit 42 is a functional unit that calculates a correction coefficient and updates the correction coefficient stored in the storage unit 46.
The correction coefficient updating unit 42 calculates a first value based on the ratio of 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. A correction coefficient Gfix is calculated and stored in the storage unit 46 as correction coefficient information 403. For example, every time the first correction coefficient Gfix is calculated, the correction coefficient updating unit 42 updates the correction coefficient information 403 (first correction coefficient Gfix) stored in the storage unit 46 to the latest value.

The method for calculating the first correction coefficient Gfix will be described in detail below.
For example, when the measuring device 100 is manufactured or shipped, a standard resistor with a highly accurate resistance value (theoretical resistance value = Rr) is connected to the measuring device 100 as the DUT 200, and the measuring device 100 Measure the resistance value. Then, the arithmetic expression (R=V/I) for calculating the resistance component is corrected so that the resistance value R of the standard resistor measured by the measuring device 100 matches the theoretical resistance value Rr (initial adjustment ).

Next, for example, at a timing immediately after the initial adjustment, the measuring device 100 switches the connection destinations of the internal terminals hci, hpi, lci, and lpi to the reference resistor Rref using the switch section 5, and the impedance calculating section 43 switches the connection destinations of the internal terminals hci, hpi, lci, and lpi to the reference resistor Rref. Measure the value Rr1. Hereinafter, the conditions after the initial adjustment (for example, temperature, humidity, elapsed time from the time of production of the measuring device 100, operating time, etc.) will be referred to as "first conditions." The measuring device 100 stores the value Rr1 of the reference resistance Rref measured under the first condition in the storage unit 46 as the reference measurement result (first condition) 401. After that, the measuring device 100 is shipped.

Consider a case where a user uses the measurement device 100 to measure the impedance of the DUT 200 after the measurement device 100 is shipped. Hereinafter, the conditions under which the user performs the measurement (for example, conditions different from the first conditions, such as temperature, humidity, elapsed time since production of the measuring device 100, and operating time) will be referred to as "second conditions."

Under the second condition, when the user operates the measuring device 100 to instruct measurement execution, the measuring device 100 first uses the switch unit 5 to connect the internal terminals hci, hpi, lci, lpi to the reference resistor Rref. , the value Rr2 of the reference resistance Rref is measured by the impedance calculation unit 43, and is stored in the storage unit 46 as a reference measurement result (second condition) 402.

Here, due to temperature changes and changes over time from the time of initial adjustment (first condition), an error of Ei occurs in the amplification factor of the operational amplifier that constitutes the current detection circuit 2 under the second condition, and the voltage detection circuit 3 Suppose that an error of Ev occurs in the amplification factor of the operational amplifier. At this time, 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 is: It can be expressed by the following formula (1).

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

As understood from the above equation (1), the value Rr2 of the reference resistance Rref measured under the second condition is the value obtained by multiplying the value Rr1 of the reference resistance Rref measured under the first condition by the error component "Er". Become. Therefore, by setting the reciprocal of the error Er as the first correction coefficient Gfix and multiplying the resistance component value Rr2 of the impedance of the DUT 200 measured under the second condition by the first correction coefficient Gfix, the impedance of the DUT 200 measured under the second condition is It becomes possible to remove the error component included in the value Rr2 of the resistance component.

Specifically, the correction coefficient updating unit 42 uses 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, and the following values stored in the storage unit 46. The first correction coefficient Gfix is calculated based on equation (2).

Calculation (updating) of the correction coefficient (first correction coefficient Gfix) by the correction coefficient updating 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 The process may be executed when 40 receives an instruction to update the correction coefficient or an instruction to measure the reference circuit 8 .

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 uses the first correction coefficient Gfix stored in the storage unit 46 to correct the value R of the resistance component of the impedance of the DUT 200 calculated by the impedance calculation unit 43, and calculates the corrected DUT measurement result ( The second condition) is stored in the storage unit 46 as 404. For example, the correction unit 44 corrects the value R of the resistance component of the impedance by performing calculation based on the following equation (3).

That is, the correction unit 44 calculates the value Rf (=R×Gfix) obtained by multiplying R by the first correction coefficient Gfix by the value of the resistance component of the impedance of the DUT 200 calculated by the impedance calculation unit 43, after correction. is stored in the storage unit 46 as the DUT measurement result (second condition) 404.

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

Next, the flow of impedance measurement by the measuring device 100 according to the first embodiment will be explained.

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

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

For example, when the 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 refer to the internal terminals hci, hpi, lci, lpi. Connect to the circuit 8 (step S1).

Specifically, when the instruction receiving unit 40 receives a signal Sd from the operation unit 7 that instructs to measure the impedance of the DUT 200, the instruction receiving unit 40 instructs the switch control unit 41 to output the internal terminals hci, hpi, Instructs to connect lci and lpi to reference resistor Rref. According to the instruction, the switch control section 41 controls the switch section 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, and connect the internal terminal lci to the terminal hpr of the reference circuit. It is connected to the terminal lcr of the reference circuit, and the internal terminal lpi is connected to the terminal lpr of the reference circuit.

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 section 40 instructs the generating circuit 1 to output voltage or current, and instructs the impedance calculating section 43 to measure impedance. The impedance calculation unit 43 acquires 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, calculates the resistance component Rr2 of the reference resistance Rref by the method described above, and calculates the resistance component Rr2 of the reference resistor Rref. It is stored in the storage unit 46 as a reference measurement result 402 under the conditions.

Next, the data processing control circuit 4 calculates (updates) the first correction coefficient Gfix (step S3). Specifically, the correction coefficient updating unit 42 uses the resistance component value Rr1 as the reference measurement result 401 under the first condition, which is stored in the storage unit 46, and the resistance component as the reference measurement result 402 under the second condition. Based on the value Rr2, the first correction coefficient Gfix is calculated by the method described above and stored in the storage unit 46. Note that when the correction coefficient Gfix is already stored in the storage unit 46, the correction coefficient updating unit 42 updates the first correction coefficient Gfix stored in the storage unit 46 using the newly calculated first correction coefficient Gfix. Rewrite.

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

Next, the data processing control circuit 4 measures the resistance component of the DUT 200 (step S5). Specifically, similarly to step S2, the instruction receiving section 40 instructs the generating circuit 1 to output voltage or current, and instructs the impedance calculating section 43 to measure 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 performs the DUT measurement. It is stored in the storage unit 46 as a result 405.

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 uses the method described above 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. The value Rf of the resistance component of the DUT 200 after the correction is calculated and stored in the storage unit 46 as the DUT measurement result 405 after the correction.

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 impedance measurement results (Rf, etc.) of the DUT 200 on the screen.

As described above, the measuring device 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. According to this, the user can easily know the error in the measurement by the measuring device 100 by measuring the impedance of the reference circuit 8 with the measuring device 100 under various conditions and comparing the measurement results.

The measuring device 100 also measures the impedance of the reference circuit 8 under the second condition based on the error between the impedance measurement result of the reference circuit 8 under the first condition and the impedance measurement result of the reference circuit 8 under a second condition different from the first condition. The impedance measurement result of the measurement target (DUT) 200 is corrected.

According to this, even if an error occurs in measurement by the measuring device 100 due to changes in the characteristics of the internal circuit of the measuring device 100 due to temperature and aging, the measuring device 100 itself corrects the error. , it becomes possible to measure impedance with higher precision.
For example, if the user performs the initial adjustment at a room temperature of 18°C as the first condition, and the user measures the DUT 200 at a room temperature of 28°C as the second condition, a conventional measurement device would take into account the effect of a temperature difference of 10°C. Must. On the other hand, according to the measuring device 100 according to the first embodiment, for example, when updating the first correction coefficient Gfix at a room temperature of 27°C, the user can , it is sufficient to consider the influence of a temperature difference of 1° C., and more accurate measurement becomes possible.

Specifically, the data processing control circuit 4 of the measuring device 100 uses 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 Rr1 of the resistance component of the impedance of the reference circuit 8 (reference resistor Rref) measured under the second condition. The value R of the resistance component of the impedance of the DUT 200 measured under the second condition is corrected based on the error from the value Rr2 of the resistance component of the impedance of the reference resistor Rref).
According to this, even if an error occurs in the measurement of the resistance component of impedance by the measuring device 100 due to temperature and age, it is possible to measure the resistance component of impedance with higher accuracy.

More specifically, the data processing control circuit 4 of the measuring device 100 calculates the value Rr1 of the resistance component of the impedance of the reference circuit 8 measured under the first condition and the resistance component of the impedance of the reference circuit 8 measured under the second condition. A first correction coefficient Gfix (=Rr1/Rr2) is calculated based on the ratio to the value Rr2, and the value R of the resistance component of the impedance of the DUT 200 measured under the second condition is corrected using the first correction coefficient Gfix ( Rf=R×Gfix).
According to this, the measured value of the resistance component of impedance can be easily corrected without using a complicated calculation formula.

In addition, in the measuring 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 The other terminal lcr, lpr of the reference circuit 8 is connected to the internal terminal lci, lpi, and the impedance calculation unit 43 calculates the resistance component value Rr2 of the impedance of the reference circuit 8 under the second condition and stores it in the storage unit 46. do. The correction coefficient updating unit 42 then updates 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 storage unit 46. The first correction coefficient Gfix may be updated based on the above.

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

According to this, the first correction coefficient Gfix can be updated at the timing desired by the user, so it is possible to realize a measuring device that is easy to use for the user.

By the way, some conventional measurement devices such as LCR meters, resistance meters, and battery testers have a so-called self-calibration function. However, in conventional self-calibration, errors in some circuits such as a voltage detection circuit and a current detection circuit are to be corrected, and only a limited correction effect can be obtained. In addition, in order to realize the self-calibration function, a reference signal output circuit consisting of a regulator IC that generates a voltage as a reference, an attenuator, a D/A conversion circuit, etc. is required depending on the circuit to be corrected. It is necessary to provide it separately, which increases the complexity of the circuit and the cost.

On the other hand, according to the measurement device 100 according to the embodiment described above, the reference circuit 8 itself has impedance and functions as a measurement target like the DUT. Therefore, by using the measurement error of the impedance of the reference circuit 8, it is possible to calibrate the entire measuring device without having to individually measure errors in the current detection circuit, errors in the voltage detection circuit, etc., and perform self-calibration for each circuit. It becomes possible to comprehensively correct measurement errors. Furthermore, by adopting a simple circuit configuration as the reference circuit 8 as described above (see FIG. 2A), circuit complexity and cost increases due to adding a measurement error correction function to the measuring device 100 can be minimized. can be kept to a limit.

≪Embodiment 2≫
FIG. 5 is a diagram showing the configuration of a measuring device 100A according to the second embodiment.

The measuring device 100A according to the second embodiment shown in FIG. In this respect, it is similar to the measuring device 100 according to the first embodiment.

In general, circuits such as voltage detection circuits and current detection circuits that constitute measurement devices such as the LCR meters described above each have unique 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 "phase characteristic."

The phase characteristics of a circuit depend on the characteristics of electronic components such as operational amplifier circuits and capacitors that make up the circuit. Therefore, when the characteristics of electronic components change due to temperature and age, the phase characteristics of the internal circuits that make up the measuring device also change.

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

Here, the phase angle of impedance is the difference between the phase of the current flowing through the object to be measured (DUT, reference circuit 8A, etc.) and the phase of the voltage of the object to be measured. 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 “θ=tan ⁻¹ (X/R)”.

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

As shown in FIG. 6, the reference circuit 8A is configured to include electronic components having a predetermined impedance. In the second embodiment, it is assumed that the reference circuit 8A is configured to include a reference resistor Rref, similarly 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. .

Note that the reference circuit 8A is not limited to the reference resistor Rref described above, and may include a capacitor, an inductor, etc. having a highly accurate reactance component.

In the measuring device 100A according to the second embodiment, the data processing control circuit 4A has a 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.

As a function of reducing the influence of phase measurement errors, the data processing control circuit 4A calculates the value of the phase angle of the impedance of the reference circuit 8 (reference resistor Rref) measured under the first condition and the reference circuit measured under the second condition. The measurement result of the phase angle of the impedance of the DUT 200 measured under the second condition is corrected based on the error with the value of the phase angle of the impedance of No. 8.

Specifically, the data processing control circuit 4A determines 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 phase angle of the impedance of the reference circuit 8A measured under the second condition. A second correction coefficient θfix is calculated based on the difference from the value θr2, and the value of the phase angle of the impedance of the DUT 200 measured under the second condition is corrected based on the second correction coefficient θfix.

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

The data processing control circuit 4A is, for example, a program processing device like the data processing control circuit 4 according to the first embodiment. The data processing control circuit 4A includes, as functional blocks for realizing the above-mentioned functions, an instruction reception section 40, a switch control section 41, a correction coefficient update section 42A, an impedance calculation section 43A, a correction section 44A, a measurement result output section 45, and a storage section 46A. These functional blocks are realized, for example, in a program processing unit (MCU) as the data processing control circuit 4A, by a processor executing various arithmetic operations according to programs stored in a storage device and controlling peripheral circuits. Ru. Note that some or all of the above functional blocks may be realized by a dedicated logic circuit.

Similar to the storage unit 46 according to the first embodiment, the storage unit 46A stores calculation formulas, various parameters, measurement results, correction coefficients, etc. necessary for measuring electrical characteristics of the DUT, calculating correction coefficients, etc. This is a functional unit that stores information.

For example, the storage 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, which will be described later, and a reference resistance Rref measured under the second condition. Reference measurement results (second condition) 402A including the measured values (Rr2, θr2), correction coefficient information 403A including the first correction coefficient Gfix and the second correction coefficient θfix, and the value of the impedance of the DUT 200 measured under the second condition. A DUT measurement result (second condition) 404A including (R, θ) and a corrected DUT measurement result (second condition) 405A including the corrected impedance value (Rf, θf) of the DUT 200 are stored.

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

In addition to the function of the impedance calculation unit 43 according to the first embodiment, the impedance calculation unit 43A has a function of calculating the value of the phase angle of impedance between the internal terminal hpi and the internal terminal lpi.

For example, when the instruction receiving unit 40 instructs to measure the phase angle of the impedance of the DUT 200, update the correction coefficient, or measure the reference circuit 8A, the generating circuit 1 generates an AC signal (for example, a constant current signal). is applied between the internal terminals hci and lci, and 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. .
For example, the instruction reception unit 40 of the data processing control circuit 4A provides the generation circuit 1 with a reference signal (for example, a sine wave signal) that is a signal having a constant frequency and a constant amplitude as the signal Sb. A generating circuit 1 generates an AC signal based on a reference signal. For example, the generation circuit 1 generates an alternating current signal (constant current) having a frequency and a constant amplitude according to the reference signal, and supplies it between internal terminals hci and lci.

The impedance calculation unit 43A calculates the value of the phase angle of the impedance between the internal terminal hpi and the internal terminal lpi based on the current detected by the current detection circuit 2 and the voltage detected by the voltage detection circuit 3 using a known method. and the value R of the resistance component of the impedance is calculated.

For example, the impedance calculation unit 43A calculates the amplitude |V| of the voltage signal v detected by the voltage detection circuit 3 by synchronous detection, the voltage phase difference θv between the reference signal and the voltage signal v in synchronous detection, and the current The amplitude |I| of the current signal i detected by the detection circuit 2 and the current phase difference θi between the reference signal and the current signal i in synchronous detection are respectively calculated. Then, the impedance calculation unit 43A uses 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 to connect the internal terminal hpi and the internal terminal lpi. |Z|=|V|/|I| and the phase angle θ=θv−θi, which is the difference between the voltage phase difference θv and the current phase difference θi, are calculated. Thereby, the value R of the resistance component of the impedance can be calculated by "R=Zcosθ", and the reactance component X of the impedance can be calculated by "X=Zsinθ".

The impedance calculation unit 43A calculates the resistance component value Rr1 (=|V1|/|I1|×cosθr1) of the impedance of the reference circuit 8A measured by the above-described method under the first condition and the phase angle value θr1 (=θv1−θi1). ) is stored in the storage unit 46. The impedance calculation unit 43A calculates the resistance component value Rr2 (=|V2|/|I2|×cosθr2) and phase angle θr2 (=θv2−θi2) of the impedance of the reference circuit 8A measured by the above-described method under the second condition. The information is stored in the storage unit 46.

As will be described later, when initial adjustment is performed in the same manner as in Embodiment 1, the correction coefficient etc. obtained by the initial adjustment are calculated using the above formula (|Z|=|V|/|I|, θ=φv -φi). Further, the impedance calculation method based on the synchronous detection described above is just one example, and the impedance calculation unit 43A may calculate the impedance using other known calculation methods.

The correction coefficient update unit 42A is a functional unit that updates the correction coefficient.
The correction coefficient update unit 42A calculates and updates the first correction coefficient Gfix, similarly to the correction coefficient update unit 42 according to the first embodiment.
Specifically, the correction coefficient updating unit 42A updates the value Rr1 (=|V1|/|I1|×cosθr1) of the resistance component of the impedance of the reference circuit 8A measured under the first condition, which is stored in the storage unit 46. The first correction coefficient Gfix is calculated based on the value Rr2 (=|V2|/|I2|×cosθr2) of the resistance component of the impedance of the reference circuit 8A measured under the second condition, and is stored in the storage unit 46A. The method for calculating the first correction coefficient Gfix is the same as the method according to the first embodiment. Further, the correction coefficient updating unit 42A calculates and updates the second correction coefficient θfix.

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

For example, during production or shipment of the measuring device 100A, a standard resistor with a highly accurate phase angle or an ideal reactance element with a highly accurate phase angle is connected to the measuring device 100A as a DUT, and the measuring device 100A Measure the phase angle of impedance. Then, the impedance calculation unit 43 is configured 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". The arithmetic expression (θ=θv−θi) for calculating the phase angle of impedance used in the calculation is corrected (initial adjustment). At this time, the measuring device 100A may also adjust the arithmetic expression for calculating the resistance component, as in the first embodiment.

Next, for example, at a timing immediately after the initial adjustment, the measuring device 100A switches the connection destination of the internal terminals hci, hpi, lci, lpi to the reference circuit 8 (reference resistance Rref) by the switch unit 5, and the impedance calculation unit 43A Accordingly, the phase value θr1 of the reference resistor Rref is measured using the method described above. Hereinafter, the conditions after the initial adjustment will be referred to as "first conditions." The measuring device 100A stores the phase value θr1 of the reference resistance Rref measured under the first condition in the storage unit 46 as the 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). Here, θv is a voltage phase difference, and θi is a current phase difference.

Note that, similarly to the first embodiment, the measuring device 100A uses the amplitude |V1| of the voltage signal v, the amplitude |I1| of the current signal i, and the phase angle θr1 (=θv1−θi1) to determine the reference resistance Rref. The resistance component value Rr1 (=|V1|/|I1|×cosθr1) is also measured and stored in the storage unit 46A together with the phase measurement value.
After that, the measuring device 100A is shipped.

Consider a case where a user measures the impedance of the DUT 200 using the measuring device 100A after the measuring device 100A is shipped. Hereinafter, the conditions under which the user performs measurement will be referred to as "second conditions."

Under the second condition, when the user operates the measuring device 100 to instruct measurement execution, the measuring device 100A first uses the switch unit 5 to connect the internal terminals hci, hpi, lci, lpi to the reference resistor Rref. , the impedance calculation unit 43A measures the phase value θr2 of the reference resistor Rref, and stores it in the storage unit 46A as a reference measurement result (second condition) 402A. At this time, the measuring device 100A uses the amplitude |V2| of the voltage signal v, the amplitude |I2| of the current signal i, and the phase angle θr2 (=θv2−θi2) to The value Rr2 (=|V2|/|I2|×cosθr2) of the resistance component of Rref is also measured and stored in the storage unit 46A together with the measured value of the phase.

Here, the phase characteristics of the current detection circuit 2 and the voltage detection circuit 3 change due to temperature changes and changes over time from the time of initial adjustment (first condition), and the output signal of the current detection circuit 2 and voltage detection under the second condition change. Assume that a phase error θe occurs between the output signal of the circuit 3 and the output signal of the circuit 3. At this time, the phase value θr2 of the reference resistor Rref measured under the second condition can be expressed by the following equation (5).

As understood from the above equation (5), the phase value θr2 of the reference resistance Rref measured under the second condition is the sum of the phase error θe from the phase value θr1 of the reference resistance Rref measured under the first condition. value. 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 is the difference between the phase value θr1 of the reference resistor Rref measured under the first condition and the reference resistor Rref measured under the second condition. This appears as an error between the phase value θr2 of the resistor Rref and the phase value θr2. Therefore, the phase error θe is expressed by the following equation (6) from the above equation (5).

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

Therefore, the phase error θe (=θr2-θr1) is set as the second correction coefficient θfix (=θr2-θr1), and the second correction is made from the phase angle value θ (=θv-θi+θe) of the impedance of the DUT 200 measured under the second condition. By subtracting the coefficient θfix (=θe), it is possible to remove the error component (θe) included in the value θ of the phase angle of the impedance of the DUT 200 measured under the second condition.

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

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

Specifically, the correction unit 44A uses the first correction coefficient Gfix included in the correction coefficient information 403A to calculate the resistance component of the impedance of the DUT 200 calculated by the impedance calculation unit 43A using the same method as the correction unit 44. Correct the value R.

Further, the correction unit 44A uses the second correction coefficient θfix (=θe) included in the correction coefficient information 403A stored in the storage unit 46A to adjust the phase angle of the impedance of the DUT 200 calculated by the impedance calculation unit 43A. The value θ is corrected and stored in the storage unit 46 as a corrected DUT measurement result (second condition) 405A. For example, the correction unit 44A corrects the value θ of the phase angle of the impedance of the DUT 200 by performing calculation based on the following equation (7).

That is, the correction unit 44A subtracts the second correction coefficient θfix (=θe) from the value θ of the phase angle of the impedance of the DUT 200 calculated by the impedance calculation unit 43A, and calculates the value θf (=θ−θfix). , is stored in the storage unit 46A as a corrected DUT measurement result (second condition) 405A.

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, phase angle θf, etc.) So corrected by the correction unit 44A. Output for 6. The output unit 6 displays information corresponding to the received measurement result So on the screen, or transmits it to an external device as measurement data, for example.

Next, the flow of impedance measurement by the measuring device 100A according to the second embodiment will be explained.

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

Below, as an example, the flow of measuring the phase of the DUT 200 will be explained, and the flow of measuring the resistance component of the DUT 200 will be omitted. Note that the flow of measuring the resistance component is the same as that in FIG. 4 described above.

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. Further, it is assumed that the DUT 200 is connected between external terminals HC and HP and external terminals LC and LP.

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

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 section 40 instructs the generating circuit 1 to output voltage or current, and instructs the impedance calculating section 43A to measure impedance. The impedance calculation unit 43A calculates the phase angle θr2 of the reference resistor Rref based on the voltage signal output from the voltage detection circuit 3 and the current signal output from the current detection circuit 2 by the method described above, and It is stored in the storage unit 46A as a reference measurement result 402A of the conditions.

Next, the data processing control circuit 4A calculates (updates) the second correction coefficient θfix (step S3A). Specifically, the correction coefficient updating unit 42A updates the phase value θr1 as the reference measurement result 401A under the first condition and the phase value θr1 as the reference measurement result 402A under the second condition, which are stored in the storage unit 46A. Based on θr2, the second correction coefficient θfix is calculated by the method described above and is stored in the storage unit 46A. Note that if the second correction coefficient θfix is already stored in the storage unit 46A, the correction coefficient update unit 42A updates the second correction coefficient θfix stored in the storage unit 46A using the newly calculated second correction coefficient θfix. Rewrite the correction coefficient θfix.

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

Next, the data processing control circuit 4A measures the phase of the DUT 200 (step S5A). Specifically, similarly to step S2A, the instruction receiving section 40 instructs the generating circuit 1 to output voltage or current, and instructs the impedance calculating section 43A to measure impedance. The impedance calculation unit 43A calculates the phase value θ of the DUT 200 by 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 calculates the DUT measurement result. It is stored in the storage unit 46A as 404A.

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 method described above using the second correction coefficient θfix stored in the storage unit 46A, The phase value θf (=θ−θfix) of the DUT 200 is stored in the storage unit 46A as the corrected DUT measurement result 405A.

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 information on the impedance measurement results (phase angle θf, etc.) of the DUT 200 on the screen, for example.

As described above, in the measuring device 100A according to the second embodiment, the data processing control circuit 4A calculates the value θr1 of the phase angle of the impedance of the reference circuit 8A measured under the first condition and the impedance of the reference circuit 8A measured under the second condition. The measurement result (θ) of the phase angle of the impedance of the DUT 200 measured under the second condition is corrected based on the difference (phase error θe) from the phase angle value θr2.
According to this, even if an error occurs in the measurement of the impedance phase angle by the measuring device 100A due to temperature and age, it is possible to measure the impedance phase angle with higher accuracy.

Specifically, the data processing control circuit 4A of the measuring device 100A determines the value θr1 of the phase angle of the impedance of the reference circuit 8A measured under the first condition and the phase angle of the impedance of the reference circuit 8A measured under the second condition. A second correction coefficient θfix (=θr1−θr2) is calculated based on the difference from the value θr2, and the value θ of the phase angle of the impedance of the DUT 200 measured under the second condition is corrected using the second correction coefficient θfix.
According to this, the measured value of the phase angle of impedance can be easily corrected without using a complicated calculation formula.

In addition, in the measuring 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 The other terminals lcr and lpr of the reference circuit 8A are connected to the internal terminals lci and lpi, and the impedance calculation unit 43A stores this in the storage unit 46 as the phase angle value (θr2) of the impedance of the reference circuit 8A under the second condition. . Then, the correction coefficient updating unit 42A updates the value (θr1) of the impedance phase angle of the reference circuit 8A under the first condition, which is stored in the storage unit 46A, and the value (θr1) of the impedance phase angle of the reference circuit 8A under the second condition. The second correction coefficient θfix (θr1−θr2) may be updated based on the value (θr2).
Here, the predetermined instruction may be an instruction to measure the DUT 200, an instruction to update a 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, so that it is possible to realize a measuring device that is easy to use for the user.

≪Embodiment 3≫
FIG. 9 is a diagram showing the configuration of a measuring device 100B according to the third embodiment.
A measuring device 100B according to Embodiment 3 shown in FIG. 9 differs from measuring

devices

100 and 100A according to

Embodiments

1 and 2 in that impedance measurement can be corrected according to the measurement range. In this respect, it is the same as the measuring

devices

100 and 100A according to the first and second embodiments.

Generally, a measuring device such as the above-mentioned LCR meter has a plurality of measurement ranges. For example, when measuring a resistor with a resistance value of several mΩ, the user can select a measurement range that corresponds to “mΩ” and measure the resistance value in that measurement range. becomes possible.

On the other hand, in order to appropriately correct measurement errors due to temperature and aging in the "mΩ" measurement range of the measuring device, the embodiments are implemented using a resistor with a resistance value in "mΩ" units as a reference circuit. It is preferable to correct the measurement error using a method similar to 1 and 2. However, it is not easy to obtain a "mΩ" resistor with sufficiently excellent temperature characteristics and long-term stability as a reference circuit. Even if such a resistor were available, it would increase component cost.
Therefore, the reference circuit 8B according to the third embodiment can achieve a pseudo-desired resistance value without using a highly stable resistor having a low resistance value of several mΩ, and can achieve a low resistance measurement range. It is possible to correct measurement errors in

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

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 dividing circuit 80, a selection circuit (MUX) 81, It has a buffer 82.

Note that 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.

The high side input terminal hcr can be connected to the internal terminal hci by a switch 51. The high side output terminal hpr can be connected to the internal terminal hpi by a switch 52. The low-side input terminal lcr can be connected to the internal terminal lci by a switch 53. The low-side output terminal lpr can be connected to the internal terminal lpi by a switch 54.

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.

In general, many measurement devices that measure the resistance value of a DUT using the four-terminal method, such as an LCR meter, generate a voltage across the DUT by applying a constant current signal or voltage signal to the DUT, as described above. The voltage is detected and the resistance value (=voltage/current) of the DUT is calculated based on Ohm's law. At this time, the resistance value calculated based on Ohm's law becomes a value proportional to the detected voltage.

Focusing on this point, in the measuring device 100B according to the third embodiment, the reference circuit 8B is realized using a voltage dividing circuit 80 composed of a plurality of resistors, and the voltage generated in the reference circuit 8B is transferred to the voltage dividing circuit 80. The voltage is divided by 80 and input to the voltage detection circuit 3. Thereby, when the measuring device 100B calculates the resistance value, the reference circuit 8B behaves like a resistor having a predetermined resistance value.

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. It has .

The first resistor Rm is connected between the high-side input terminal hcr and the low-side input terminal lcr. It is preferable that the first resistor Rm is a precision resistor having high accuracy and high reliability, similar to the reference resistor Rref according to the first and second embodiments.

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 the measuring device 100A. In Embodiment 3, as an example, the measurement device 100B has three (n=3) resistance measurement ranges, and the three second resistors Ra1 to Ra3 connect to the high side input terminal hcr and the low side input terminal lcr. The following explanation assumes that the two are connected in series.

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

It is preferable that the second resistors Ra1 to Ran are highly accurate and highly reliable resistors like the first resistor Rm. However, it is not necessarily necessary that each of the second resistors Ra1 to Ran has the same degree of precision and reliability as the first resistor Rm, and at least the second resistors Ra1 to Ran are As long as it is highly accurate and reliable, it is sufficient. For example, the second resistors Ra1, Ra2, and Ra3 have a relative temperature coefficient of resistance value of ±5 ppm/℃ or less between each resistor, and a relative long-term stability of the resistance value between each resistor. Preferably, it is a precision network resistor with a value of ±100 ppm/year or less.

In the voltage divider 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, lpi, the current flowing through the voltage dividing circuit 80 is dominated by the current flowing through the first resistor Rm. becomes.

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 divider circuit 80, that is, the resistance value of the first resistor Rm and the network resistor Ratt is The combined resistance value Rcomb is expressed by the following formula (8).

When the current flowing through the voltage dividing circuit 80 (the current detected by the current detecting circuit 2) by applying a constant current signal to the voltage dividing circuit 80 by the generating circuit 1 is I, the voltage V generated in the voltage dividing circuit 80 is becomes “V=I×Rcomb”.

Further, when the voltage division coefficient Xatt (≦1) of the network resistor Ratt is set, the voltage Vatt divided by the voltage dividing circuit 80 is “Vatt=Xatt×V”.

Therefore, when the resistance value of the reference circuit 8B (reference resistance) calculated by the measuring device 100B is Rref, the following formula (9) is obtained.

As understood from the above equation (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.

Here, since Rm<<Ratt, Rcomb≈Rm. Therefore, fluctuations in the combined resistance value Rcomb due to temperature and time are dominated by fluctuations in the first resistor Rm, and fluctuations in the network resistor Ratt can be ignored. Therefore, as described above, by employing a precision resistor with high accuracy and high reliability (high stability) as the first resistor Rm, the composite resistance value Rcomb also exhibits high accuracy and high reliability. It turns out.

In addition, as mentioned above, as the network resistor Ratt, a precision network resistor with relatively high resistance value between each second resistor Ra1 to Ran and high reliability (high stability) is adopted. By doing so, the partial pressure coefficient Xatt also exhibits high precision and high reliability.

In this way, according to the voltage dividing circuit 80, a reference resistor having a desired resistance value, high accuracy, and high reliability can be realized in a pseudo manner.

Hereinafter, a specific example of the configuration of the reference circuit 8B will be described. Here, a case will be described in which a 10 mΩ resistor and a 100 mΩ resistor are simulated by the reference circuit 8B.

For example, as shown in FIG. 10, the first resistor Rm is set to 1Ω. Further, in the network resistor Ratt, the second resistor Ra1 is 9 kΩ, the second resistor Ra2 is 900Ω, and the second resistor Ra3 is 100Ω.

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

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

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 a resistor with a resistance value lower than 1Ω. Can be done.

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

The selection circuit 81 selects the voltage between the high-side input terminal hcr and the low-side input terminal lcr (the voltage at the terminal Pa1) and the plurality of voltages divided by the voltage dividing circuit 80 (the voltages at the terminals Pa2 and Pa3). One of the input voltages is selected and output between the high-side output terminal hpr and the low-side output terminal lpr.

Specifically, a selection signal Ss specifying the measurement range of the measurement device 100 is input to the selection circuit 81. The selection circuit 81 selects and outputs a voltage corresponding to the measurement range designated by the selection signal Ss from among the plurality of input voltages.

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

The buffer 82 is a circuit that receives a signal with high input impedance and outputs a signal with low output impedance. As the buffer 82, for example, an operational amplifier can be used.

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.

Note that, for example, if the output impedance of the selection circuit 81 is sufficiently low, or if 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).

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

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

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 calculates (updates) a correction coefficient and corrects impedance measurement results for each specified measurement range. It has the function to perform

The data processing control circuit 4B is, for example, a program processing device like 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 includes, as functional blocks for realizing the above-mentioned functions, an instruction reception section 40B, a switch control section 41, a correction coefficient update section 42B, an impedance calculation section 43A, a correction It has a section 44B, a measurement result output section 45, and a storage section 46B. These functional blocks are realized, for example, in a program processing unit (MCU) as the data processing control circuit 4B, by a processor executing various arithmetic processes according to programs stored in a storage device and controlling peripheral circuits. Ru. Note that some or all of the above functional blocks may be realized by a dedicated logic circuit.

Similar to the instruction receiving unit 40 according to the first and second embodiments, the instruction receiving unit 40B receives a signal Sd from the operation unit 7 and transmits a signal instructing execution of processing according to the signal Sd to other functional units. Output for.

For example, when the user specifies a measurement range and instructs execution of the impedance measurement of the DUT 200 by operating the operation unit 7, the instruction receiving unit 40, in response to the signal Sd output from the operation unit 7, Provides a selection signal Ss specifying a measurement range to the reference circuit 8B, and instructs the switch control unit 41, correction coefficient update unit 42B, impedance calculation unit 43B, etc. to execute processing for measuring the impedance of the DUT 200. do. Further, as in the second embodiment, the instruction reception unit 40 provides the generation circuit 1 with a reference signal (for example, a sine wave signal) having a constant frequency and a constant amplitude as the signal Sb. generates an alternating current signal based on the reference signal. For example, the generation circuit 1 supplies an alternating current signal (constant current) having a frequency synchronized with a reference signal and a constant amplitude between internal terminals hci and lci.

The impedance calculation unit 43B is based on the voltage value detected by the voltage detection circuit 3 and the current value detected by the current detection circuit 2, similarly to the impedance calculation units 43 and 43A according to the first and second embodiments. Then, the value of the impedance between the internal terminal hpi and the internal terminal lpi is calculated.

For example, in the first condition, when measuring the impedance of the reference circuit 8B using the measurement range k (1<k≦n), the instruction receiving section 40B outputs the selection signal Ss specifying the measurement range k, and the reference circuit 8B A voltage corresponding to the measurement range k specified by the selection signal Ss is input to the voltage detection circuit 3. The impedance calculation section 43B uses the same method as the impedance calculation sections 43 and 43A according to the first embodiment or the second embodiment, based on the current detected by the current detection circuit 2 and the voltage detected by the voltage detection circuit 3. , the impedance values (Rr1_k, θr1_k) of the reference circuit 8B are calculated and stored in the storage unit 46B as the reference measurement result 401_k (first condition) of the measurement range k. Similarly, when measuring the impedance of the reference circuit 8B using the measurement range k under the second condition, the impedance calculation section 43B uses the same method as the impedance calculation sections 43 and 43A according to the first embodiment or the second embodiment. , the impedance value (Rr2_k, θr2_k) of the reference circuit 8B according to the measurement range k under the second condition is calculated and stored in the storage unit 46B as the reference measurement result 402_k (second condition) of the measurement range k.

In this way, the impedance calculation unit 43B measures the impedance of the reference circuit 8B for each measurement range 1 to n, and generates reference measurement results (first conditions) 401B_1 to 401B_n and reference measurement results (second conditions) 402B_1 to 402B_n. is stored in the storage unit 46B.

The correction coefficient update unit 42B calculates the first correction coefficient Gfix and the second correction coefficient θfix for each measurement range 1 to n using the same method as the correction

coefficient update units

42 and 42 according to the first and second embodiments, It is stored in the storage unit 46 as correction coefficient information 403_1 to 403_n, and the values of correction coefficient information 403_1 to 403_n are updated.

For example, when calculating the correction coefficient information 403_k for the measurement range k, the correction coefficient update unit 42B uses the reference measurement result 401B_k (Rr1_k, θr1_k) under the first condition in the measurement range k stored in the storage unit 46B. , the first correction coefficient Gfix_k and the second correction coefficient θfix_k are determined by the same method as in the first and second embodiments based on the difference from the reference measurement result 402B_k (Rr2_k, θr2_k) under the second condition in the measurement range k. It is calculated and stored in the storage unit 46B as correction coefficient information 403_k.

The correction unit 44B is a functional unit that corrects the impedance value calculated by the impedance calculation unit 43B using the correction coefficient information 403B_1 to 403B_n. The correction unit 44B corrects the measured value (R, θ) of the impedance of the DUT 200 calculated by the impedance calculation unit 43B based on the correction coefficient information 403_1 to 403_n stored in the storage unit 46B, and the corrected DUT The measurement result (second condition) is stored in the storage unit 46B as a measurement result (second condition) 405B.

For example, when correcting the measurement result in measurement range k, correction unit 44B uses correction coefficient information 403_k (Gfix_k, θfix_k) corresponding to measurement range k to correct

correction unit

44, 44A according to

Embodiments

1 and 2. The impedance measurement value (R_k, θ_k) of the DUT 200 in the measurement range k is corrected using the same method as that of the DUT 200 impedance measurement value (Rf_k, θf_k) after the correction. Condition) 405B is stored in the storage unit 46B.

Similar to the

storage units

46 and 46A according to

Embodiments

1 and 2, the storage unit 46B stores calculation formulas, various parameters, measurement results, etc. necessary for measuring electrical characteristics of the DUT, calculating correction coefficients, etc. This is a functional unit that stores correction coefficients and the like.

For example, as described above, the storage unit 46B stores reference measurement results (first conditions) 401B_1 to 401B_n and reference measurement results (second conditions) 402B_1 to 402B_n for each measurement range. Further, the storage unit 46B 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. Furthermore, the storage unit 46B stores the DUT measurement results (second condition) 404B including the impedance measurement values (R, θ) of the DUT 200 under the second condition, and the corrected impedance measurement values (Rf, θf) of the DUT 200. ) The corrected DUT measurement result (second condition) 405B is stored.

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

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

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

Next, the data processing control circuit 4B controls the reference circuit 8B so that the 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 instructing the measurement range k specified by the user, and the selection circuit 81 of the reference circuit 8B corresponds to the measurement range k specified by the selection signal Ss. Enable voltage output. For example, when the measurement range k is "100 mΩ", the selection circuit 81 enables output of the voltage at the terminal Pa2 (Xatt=0.1) of the network resistor Ratt.

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

Next, the data processing control circuit 4B calculates correction coefficient information 403_k corresponding to measurement range k (step S3B). Specifically, the correction coefficient updating unit 42B uses the reference measurement result 401B_k (Rr1_k, θr1_k) of the measurement range k under the first condition, which is stored in the storage unit 46B, and the measurement under the second condition measured in step S2B. Based on the reference measurement result 402B_k (Rr2_k, θr2_k) of range k, the first correction coefficient Gfix_k and second correction coefficient θfix_k of measurement range k are calculated by the method described above, and stored in the storage unit 46B as correction coefficient information 403_k. Remember.

Note that if the correction coefficient information 403_k is already stored in the storage unit 46B, the correction coefficient update unit 42B stores the newly calculated first correction coefficient Gfix_k and second correction coefficient θfix_k in the storage unit 46B. The first correction coefficient Gfix_k and the second correction coefficient θfix_k that have been set are rewritten.

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

Next, the data processing control circuit 4B measures the phase value θ of the DUT 200 in the measurement range k (step S5B). Specifically, similarly to step S2B, the instruction receiving unit 40B instructs the generating circuit 1 to output voltage or current, and instructs the impedance calculating unit 43A to measure 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 based on the voltage signal output from the voltage detection circuit 3 and the current signal output from the current detection circuit 2 using the method described above. It is calculated and stored in the storage unit 46B, for example, as a DUT measurement result 404B (second condition).

Next, the data processing control circuit 4B corrects the measured value (R_k, θ_k) of the impedance of the DUT 200 in the measurement range k, which was measured in step S5B (step S6B). Specifically, the correction unit 44B multiplies the value R_k of the resistance component of the DUT 200 in the measurement range k measured in step S5B by the first correction coefficient Gfix_k of the measurement range k stored in the storage unit 46B. Accordingly, the corrected resistance component value Rf_k (=R_k×Gfix_k) is calculated. Further, the correction unit 44B subtracts the second correction coefficient θfix_k of the measurement range k stored in the storage unit 46B from the phase value θ_k of the DUT 200 measured in step S5B, so that the corrected phase value θf_k (=θ_k−θfix) is calculated. The correction unit 44B stores the calculated corrected resistance component value Rf_k and phase value θf_k in the storage unit 46B as a corrected DUT measurement result 405B_k.

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 impedance measurement result (resistance component value Rf_k, phase angle θf_k, etc.) of the DUT 200 in the measurement range k on the screen.

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

According to this, as described above, the resistance value of the first resistor Rm and each resistance value (voltage division coefficient Xatt) of the plurality of second resistors Ra1 to Ran constituting the network resistor Ratt are appropriately set. As a result, a reference circuit (resistance) having a desired resistance value can be virtually realized without using a highly stable resistor having a low resistance value of several mΩ.

In addition, as described above, the selection circuit 81 selects and outputs the voltage corresponding to the selection signal Ss that specifies the measurement range from among the plurality of voltages output from the voltage dividing circuit 80. It becomes possible to correct measurement errors using the correction coefficient, and it becomes possible to measure impedance with higher precision in each measurement range.

≪Expansion of the embodiment≫
Although the invention made by the present inventor has been specifically explained based on the embodiments above, the present invention is not limited thereto, and the combination of components may be changed between each embodiment. However, various changes may be made to the constituent elements of the invention without departing from the gist of the invention.

For example, in

Embodiments

1 and 2, the

measurement apparatuses

100 and 100A measure the impedance of the DUT 200 using the four-terminal method, but the present invention is not limited to this. Good too.

FIG. 13 is a diagram showing the configuration of a measuring device 100C capable of measuring impedance using a two-terminal method.

As shown in FIG. 13, the measuring 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 a second internal terminal. It has an internal terminal li as a terminal. Further, the reference circuit 8C has, for example, a terminal hr as a high-side terminal and a terminal lr as a low-side terminal. Note that the reference circuit 8C may have the same internal configuration as the

reference circuits

8 and 8A, for example.

The generating circuit 1 applies a voltage or current between the internal terminal hi and the internal terminal li. Current detection circuit 2 detects a current flowing between internal terminal hi and internal terminal li. For example, the current detection 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 detection circuit 2 is connected in series between the negative output terminal of the generation circuit 1 and the internal terminal li.

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. Voltage detection circuit 3 detects and outputs the voltage between internal terminals hi and li.

The switch section 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 in accordance with the signal Sc from the data processing control circuit 4, and also switches the connection destination of the internal terminal li between the external terminal H and one terminal hr of the reference circuit 8C. The connection destination is switched between the external terminal L and the other terminal lr of the reference circuit 8C. Each of the

switches

51C and 53C constituting the switch section 5C is configured, for example, by a double-throw switch element, similar to the switch 51 and the like described above.

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

According to the measurement device 100C described above, even when measuring impedance using the two-terminal method, the user can measure the impedance of the reference circuit 8C with the measurement device 100C under various conditions and compare the measurement results. By doing so, it is possible to easily know the error in measurement by the measuring device 100C, and it is also possible to measure impedance with higher accuracy.

Furthermore, in the second embodiment, the data processing control circuit 4A corrects the measured value of impedance using the first correction coefficient Gfix and the second correction coefficient θfix, but the present invention is not limited to this. For example, the data processing control circuit 4A may only correct the measured value of the phase angle of impedance using the second correction coefficient θfix. Similarly, the data processing control circuit 4B according to the third embodiment may correct the measured value of impedance using only one of the first correction coefficient Gfix and the second correction coefficient θfix.

Further, in the third embodiment, the measurement device 100B includes the reference circuit 8B, but the reference circuit 8B is not limited to this, and the reference circuit 8B may be implemented as a “standard resistor” separate from the measurement device 100B. good. In this case, the reference circuit 8B as a standard resistor 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 dividing circuit 80, and a selection circuit 81. It is one device.

According to this, the high-side input terminal hcr, high-side output terminal hpr, and By connecting the low-side input terminal lcr and the low-side output terminal lpr, it is possible to correct measurement errors using the reference circuit 8B (standard resistor) even in existing measuring devices.

Note that in Embodiments 1 to 3, the case where the measuring

devices

100, 100A, 100B, and 100C have the current detection circuit 2 is illustrated, but the present invention is not limited to this. For example, when the current value flowing through the measurement target (DUT or

reference circuit

8, 8A, 8B) is known, such as when the generation circuit 1 outputs a constant current, the current detection circuit 2 may not be provided. good. In this case, the

arithmetic circuits

4, 4A, 4B may calculate the impedance using the method described above using current values stored in advance in the

storage units

46, 46A, etc.

Furthermore, the above-mentioned flowchart shows an example for explaining the operation, and is not limited thereto. That is, the steps shown in each figure of the flowchart are specific examples, and the flowchart is not limited to this flow. For example, the order of some processes may be changed, other processes may be inserted between each process, or some processes may be performed in parallel.

Further, in the reference circuit 8B according to the third embodiment, the voltage dividing circuit 80 includes a first resistor Rm and a plurality of second resistors Ra1 to Ran (n is 2) connected in parallel with the first resistor Rm. (the above integer), but the present invention is not limited to this, and various circuit configurations that can realize the function as a voltage dividing circuit can be adopted. FIG. 14 shows another example of the reference circuit.

The reference circuit 8B shown in FIG. 14 includes a first resistor Rm, a plurality of second resistors Ra0 to Ra3 connected in parallel with the first resistor Rm, and a third resistor Rc. For example, the first resistor Rm is 1Ω, the second resistor Ra0 is 2kΩ, the second resistor Ra1 is 900Ω, the second resistor Ra2 is 900Ω, the second resistor Ra3 is 100Ω, and the third resistor Rc is 100Ω.

The third resistor Rc is connected in parallel with at least one resistor among the second resistors Ra0 to Ra3 connected in series. Preferably, the third resistor Rc is connected in parallel with at least two resistors connected in series among the second resistors Ra0 to Ra3. For example, one end of the third resistor Rc is connected to a node Nc to which the low-side input terminal lcr and the low-side output terminal lpr are commonly connected, and the other end of the third resistor Rc is It is connected to one of the connected nodes. As an example, FIG. 14 shows a case where one end of the third resistor Rc is connected to the node Nc, and the other end of the third resistor Rc is connected to the terminal Pa2.
According to this, it is possible to obtain a smaller voltage division ratio, and therefore it is possible to realize a desired resistance value with higher precision. Note that the connection destination of the resistor Rc is not limited to the example shown in FIG. 14, and can be variously changed depending on the desired resistance value.

DESCRIPTION OF SYMBOLS 1... Generation circuit, 2... Current detection circuit, 3... Voltage detection circuit, 4... Data processing control circuit, 5... Switch section, 6... Output section, 7... Operation section, 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 ~54... Switch, 80... Voltage divider circuit, 81... Selection circuit, 82... Buffer, 401, 401A, 401B_1 to 401B_n... Reference measurement result (first condition), 402, 402A, 402B_1 to 402B_n... Reference measurement result (first condition) 2 conditions), 403, 403A, 403B_1 to 403B_n... Correction coefficient 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, Ra0 to Ran...second resistor, Rc...third Resistor, Ratt...network resistor, Sb...signal (reference signal), Sc...signal, Ss...selection signal, So...measurement result.

Claims

a first external terminal for connecting one terminal of the 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 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;
Measuring 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 data processing control circuit to
a reference circuit having two terminals and a predetermined impedance;
The connection destination of the first internal terminal is switched between the first external terminal and one terminal of the reference circuit, and the connection destination of the second internal terminal is switched between the second external terminal and the other terminal of the reference circuit. A switch section for switching between the terminal and the terminal,
In the data processing control circuit, under a first condition, one terminal of the reference circuit and the first internal terminal are connected by the switch unit, and the other terminal of the reference circuit and the second internal terminal are connected. One terminal of the reference circuit and the first internal terminal are connected by the switch unit under a second condition different from the first condition and a measurement result of the impedance of the reference circuit when connected, and A correction coefficient is calculated based on an error between the impedance measurement result of the reference circuit when the other terminal of the reference circuit and the second internal terminal are connected, and the correction coefficient is calculated by the switch unit under the second condition. between the first internal terminal and the second internal terminal when the first external terminal and the first internal terminal are connected, and the second external terminal and the second internal terminal are connected; A measuring device that corrects impedance measurement results based on the correction coefficient.
The measuring device according to claim 1,
The generation circuit supplies an AC signal based on a reference signal having a constant frequency and a constant amplitude between the first internal terminal and the second internal terminal,
The data processing control circuit detects, through synchronous detection, the amplitude of the voltage signal detected by the voltage detection circuit, the voltage phase difference between the reference signal and the voltage signal, and the first internal terminal and the second internal terminal. The amplitude of the voltage signal, the voltage phase difference, and the current signal are calculated by respectively calculating the amplitude of the current signal flowing between the internal terminal and the current phase difference between the reference signal and the current signal. and the current phase difference, the value of the resistance component of the impedance between the first internal terminal and the second internal terminal, and the difference between the voltage phase difference and the current phase difference. A measuring device that calculates values of phase angles of impedance between the first internal terminal and the second internal terminal.
The measuring device according to claim 2,
The data processing control circuit, based on the 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, A measuring device that corrects a value of a resistance component of impedance of the test object measured under the second condition.
The measuring device according to claim 3,
The data processing control circuit calculates, as the correction coefficient, a value of a resistance component of the impedance of the reference circuit measured under the first condition and a value of a resistance component of the impedance of the reference circuit measured under the second condition. A measuring device that calculates a first correction coefficient based on the ratio, and uses the first correction coefficient to correct a value of a resistance component of the impedance of the test object measured under the second condition.
The measuring device according to claim 2,
The data processing control circuit, based on the 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, A measuring device that corrects a phase angle value of impedance of the test object measured under the second condition.
The measuring device according to claim 5,
The data processing control circuit calculates, as the correction coefficient, a value of the phase angle of the impedance of the reference circuit measured under the first condition and a value of the phase angle of the impedance of the reference circuit measured under the second condition. A measuring device that calculates a second correction coefficient based on the difference, and uses the second correction coefficient to correct a phase angle value of the impedance of the test object measured under the second condition.
The measuring device according to claim 2,
The data processing control circuit includes:
an instruction receiving unit that receives instructions to the measuring device;
a storage unit that stores an impedance value of the reference circuit measured under the first condition and correction coefficient information including the correction coefficient;
a switch control section that controls the switch section;
an impedance calculation unit that calculates an impedance value 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 updating 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 section calculates the impedance value between the first internal terminal and the second internal terminal, and calculates the impedance of the reference circuit measured under the second condition. The correction coefficient updating unit stores the impedance value of the reference circuit measured under the first condition, which is stored in the storage unit, as a value, and the impedance value measured under the second condition. A measuring device that updates the correction coefficient information based on the impedance value of the reference circuit.
The measuring device according to claim 1,
The reference circuit includes a resistor. Measuring device.
The measuring device according to claim 1,
The first internal terminal includes a high-side internal application terminal to which a voltage or 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 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 is
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; a plurality of second resistors connected in series between the high-side input terminal and the low-side input terminal;
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 are input, and one of the input voltages is selected. a selection circuit for outputting between the high-side output terminal and the low-side output terminal; the switch section selects a connection destination of the high-side internal application terminal between the high-side external application terminal and the reference circuit; switching the connection destination of the low-side internal application terminal between the low-side external application terminal and the low-side input terminal of the reference circuit; and switching the connection destination of the high-side internal detection terminal between the low-side external application terminal and the low-side input terminal of the reference circuit. Switching between the high side external detection terminal and the high side output terminal of the reference circuit, and switching the 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 device.
The measuring device according to claim 9,
The reference circuit further includes a third resistor connected in parallel with at least one resistor among the plurality of second resistors. The measuring device.
The measuring device according to claim 10,
A selection signal specifying a measurement range is input to the selection circuit,
The selection circuit selects and outputs a voltage corresponding to a measurement range designated by the selection signal from among the input voltages.
The measuring device according to claim 9,
The plurality of second resistors are network resistors. Measuring device.
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 third resistor connected in parallel with at least one resistor among the plurality of second resistors;
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 are input, and one of the input voltages is selected. a selection circuit that outputs between the high side output terminal and the low side output terminal.