Sensor circuit and electronic device

Abstract

Sensor circuit (3, 3A) for measuring a current or voltage in a line of an electronic device with a circuit section (2, 2A) in which a drive circuit (21, 21A) and a load circuit (22, 22A) are connected by one or more lines (23, 23U, 23V, 23W), wherein the sensor circuit (3, 3A) comprises: a resistance for detection (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ), which is connected to one or more wires (23, 23U, 23V, 23W); a first pair of terminals (31, 31U, 31V, 31W) comprising connecting wires, each connected to the terminals of the resistor to be measured (R) S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W are connected; a second pair of terminals (32, 32U, 32V, 32W) comprising connecting wires that are attached to one terminal of the resistor for detection (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ) are short-circuited together; and a sensor section (33, 33A, 33B) for measuring the current or voltage from which a noise component is removed, using a detection signal supplied to it via the first terminal pair (31, 31U, 31V, 31W) and a detection signal supplied to it via the second terminal pair (32, 32U, 32V, 32W); where the detection resistor is a series resistor circuit comprising a first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and a second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) includes, wherein the first pair of terminals (31, 31U, 31V, 31W) comprises connecting wires which are each connected to terminals of the series resistor circuit, and where the first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) in line (23) are connected in series and the second terminal pair (32, 32U, 32V, 32W) comprises connecting wires that are short-circuited together at a terminal where the first detection resistor (R) S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) are connected to each other in the series resistor circuit; or where the first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U, R S_2_V , R S_2_W ) in series between two lines (23, 23A) from the several lines connecting the drive circuit and the load circuit, and the second pair of terminals comprises connecting wires that are short-circuited together at a terminal where the first sensing resistor (R) S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) are connected in the series resistor circuit.

Description

[0001] The present disclosure relates to a sensor circuit and an electronic device. GENERAL STATE OF THE ART

[0002] The common-mode noise emission in a differential device is quantitatively expressed by the common-mode emission ratio (hereinafter referred to as CMRR). For example, a conventional technique for improving CMRR is the differential probe described in Patent Literature 1. A common-mode choke coil (hereinafter referred to as CMC) is connected to a pair of contact terminals included in the differential probe. The CMC has a high impedance to common-mode noise, thereby reducing common-mode noise flowing into the differential probe.

[0003] Document DE 10 2017 120 405 A1 describes a current detection circuit that detects a current flowing in a current path in a motor drive device. REFERENCE LISTPATENT LITERATURE

[0004] Patent literature 1: JP H07-12 871 A SUMMARY OF THE INVENTIONTECHNICAL PROBLEM

[0005] The differential probe described in Patent Literature 1 is a sensor circuit with a CMC, and parasitic capacitance inevitably occurs at both ends of the coil winding in the CMC. Since the parasitic capacitance occurring in the CMC reduces the impedance of the CMC to high-frequency common-mode noise, a problem arises in that the common-mode noise reduces the measurement accuracy in a high-frequency range.

[0006] The present disclosure is intended to solve the above-mentioned problem, and therefore, it is an object of the present disclosure to provide a sensor circuit that can remove an error caused by a noise component from a measured value of a current or a voltage in a wire connecting a drive circuit and a load circuit included in an electronic device, and an electronic device including the sensor circuit. SOLUTION TO THE PROBLEM

[0007] This object is achieved by subject matter having the features according to the independent claims. Advantageous embodiments of the invention are the subject of the figures, the description and the dependent claims. A sensor circuit further disclosed here measures a current or a voltage in a wire of an electronic device having a circuit section in which a drive circuit and a load circuit are connected by one or more wires, the sensor circuit comprising: a sensing resistor connected to one or more wires; a first terminal pair comprising lead wires respectively connected to the terminals of the sensing resistor; a second terminal pair comprising lead wires short-circuited together at one terminal of the sensing resistor; and a sensor section for measuring the current or voltage from which or from which a current or voltage is output.which a noise component is removed using a detection signal supplied thereto via the first terminal pair and a detection signal supplied thereto via the second terminal pair. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0008] According to the present disclosure, a detection signal input through a first terminal pair is superimposed with a common-mode noise component in addition to a differential component, which is the true value of a current or voltage in one or more lines. Because a second terminal pair is short-circuited at one terminal of a detection resistor, only a common-mode noise component, which represents an error, is included in a detection signal input through the second terminal pair.By subtracting the noise component input via the second terminal pair from the detection signal input via the first terminal pair, the sensor circuit according to the present disclosure can remove the error caused by the noise component from a measured value of the current or voltage in the one or more wires connecting a drive circuit and a load circuit included in electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing an example of the configuration of an electronic device according to Embodiment 1; Fig. 2 is a block diagram showing the configuration of a variant of a sensor circuit; Fig. 3 is a block diagram showing an example of the configuration of a sensor section; Fig. 4 is an explanatory drawing showing an overview of noise correction performed by the sensor section; Fig. 5 is a block diagram showing the configuration of a variant of the sensor section; Fig. 6 is a block diagram showing an example of the configuration of an electronic device according to Embodiment 2; Fig. 7 is a block diagram showing the configuration of a variant of a sensor circuit; Fig. Fig. 8 is a block diagram showing the configuration of a variant (1) of the electronic device according to Embodiment 2; and Fig. 9 is a block diagram showing the configuration of a variant (2) of the electronic device according to Embodiment 2. DESCRIPTION OF THE EMBODIMENTS Embodiment 1.

[0009] Fig. 1 is a block diagram showing an example of the configuration of the electronic device 1 according to Embodiment 1. In Fig. 1, the electronic device 1 includes a circuit section 2, a sensor circuit 3, and a control unit 4. The circuit section 2 includes a drive circuit 21 and a load circuit 22, and the drive circuit 21 and the load circuit 22 are electrically connected by a wire 23. The drive circuit 21 drives the load circuit 22 and applies a voltage V S to the wire 23. The load circuit 22 has an impedance Z L and is controlled by the drive circuit 21. The circuit section 2 is connected via a parasitic capacitance C P coupled to a reference GND, which has a ground potential. Circuit section 2 is provided with a loop path that carries the parasitic capacitance C P and in this loop path there is a common mode noise with a voltage VC available.

[0010] The sensor circuit 3 measures a current or a voltage that the drive circuit 21 supplies to the load circuit 22 via the wire 23. More specifically, the sensor circuit 3 measures the current or the voltage in the wire 23. The sensor circuit 3 includes a first detection resistor R S_1 and a second detection resistor R S_2 , each connected to the wire 23 as a detection resistor, a first terminal pair 31, a second terminal pair 32 and a sensor section 33. The first detection resistor R S_1 and the second detection resistor R S_2 form a series resistance circuit connected in two series in the wire 23. In addition, the first detection resistor R S_1 and the second detection resistor R S_2 Resistor elements with the same resistance value R S .

[0011] The first terminal pair 31 consists of connecting wires that are connected to the wires 34 and 35 of the detection resistor. Fig. 1, the first terminal pair 31 consists of a connecting wire which is connected to the terminal 34 in the first detection resistor R S_1 the above-mentioned series resistance circuit, wherein the terminal 34 is connected to the second detection resistor R S_2 opposite, and a connecting wire connected to terminal 35 in the second detection resistor R S_2 the series resistance circuit, wherein the terminal 35 is connected to the first detection resistor R S_1 opposite.

[0012] The second terminal pair 32 consists of two connecting wires that are short-circuited together at a terminal 36 of the detection resistor. Fig. 1, the two connecting wires forming the second terminal pair 32 are connected together and short-circuited at the terminal 36, at which the first detection resistor R S_1 and the second detection resistor R S_2 connected in the series resistor circuit.

[0013] The sensor section 33 measures the current or voltage from which a noise component in the wire 23 is removed, using a detection signal supplied thereto via the first terminal pair 31 and a detection signal supplied thereto via the second terminal pair 32. The measurement data on the current or voltage measured by the sensor section 33 is output to the control unit 4. The electronic device 1 contains other than those in Fig. 1. The control unit 4 controls the operation of the components based on the measured current or voltage value measured by the sensor circuit 3 of the circuit section 2.

[0014] Fig. 2 is a block diagram showing the configuration of a sensor circuit 3A, which is a variant of the sensor circuit 3. As shown in Fig. 2, a detection resistor included in the sensor circuit 3A is a series resistance circuit in which a first detection resistor R S_1 and a second detection resistor R S_2 between a wire 23 and a wire 23A and connected in series with the wire 23. The wire 23A is the one that has a parasitic capacitance C Pcoupled to a reference potential GND, which has a ground potential, by the wires connecting a drive circuit 21 and a load circuit 22. In the detection resistor configured in this way, the first terminal pair 31 consists of connecting wires connected to the terminals 37 and 38, respectively, of the series resistance circuit, and the second terminal pair 32 consists of two connecting wires short-circuited at a terminal 39, to which the first detection resistor R S_1 and the second detection resistor R S_2 connected in the series resistor circuit as shown in Fig. 2 shown.

[0015] Fig. 3 is a block diagram showing an example of the configuration of the sensor section 33. As shown in Fig. As shown in Figure 3, the sensor section 33 includes a signal measuring circuit 331, a noise measuring circuit 332, and a noise correction circuit 333. The signal measuring circuit 331 and the noise measuring circuit 332 are identical in their circuit configuration. The signal measuring circuit 331 includes an amplification circuit 3311 and amplifies the current or voltage detection signal containing the noise component, which is input via the first terminal pair 31. Fig. 3, the amplifying circuit 3311 amplifies the detection signal supplied to it via the first terminal pair 31 and outputs the amplified signal (voltage V OUT1 ) to the noise correction circuit 333.

[0016] The noise measuring circuit 332 includes an amplification circuit 3321 and amplifies the detection signal containing only the noise component, the detection signal being fed into this circuit via the second terminal pair 32. In Fig. 3, the amplifying circuit 3321 amplifies the detection signal supplied to it via the second terminal pair 32 and outputs the amplified signal (voltage V OUT2 ) to the noise correction circuit 333. The amplification circuit 3311 and the amplification circuit 3321 consist of, for example, inverting or non-inverting amplification circuits, each using an operational amplifier.

[0017] The noise correction circuit 333 includes an analog subtraction circuit 3331 and subtracts the value of the detection signal amplified by the noise measurement circuit 332 from the value of the detection signal amplified by the signal measurement circuit 331. The analog subtraction circuit 3331 outputs an analog signal with a voltage V OUT1 -V OUT2 to the control unit 4 by applying the voltage V OUT2 , which is supplied to it by the noise measuring circuit 332, from the voltage V OUT1subtracted from the signal supplied to it by the signal measuring circuit 331. The analog subtraction circuit 3331 consists, for example, of a subtraction circuit that uses an operational amplifier.

[0018] In addition, the first terminal pair 31 and the second terminal pair 32 are equal to each other in the wire length of the lead wire. For example, if the first terminal pair 31 consists of a lead wire (1) connecting the terminal 34 and a positive terminal (+) of the amplification circuit 3311, and a lead wire (2) connecting the terminal 35 and a negative terminal (-) of the amplification circuit 3311, and the second terminal pair 32 consists of a lead wire (3) and a lead wire (4) shorted by the terminal 36, the lead wires (1) to (4) have the same wire length as each other.

[0019] Fig. 4 is an explanatory drawing showing an overview of the noise correction performed by the sensor section 33. As shown in Fig. 4, the positive terminal (+) of the first terminal pair 31 is connected to the terminal 34 in the wire 23, and the negative terminal (-) of the first terminal pair 31 is connected to the terminal 35 in the wire 23. The electrical potential V P of terminal 34 with respect to the reference potential GND, which represents the ground potential, is expressed by the following equation (1). In the following equation (1), V S the voltage applied by the drive circuit 21 to the wire 23, and V C is the common mode noise voltage. VP=VS+VC

[0020] The electrical potential V Nof terminal 35 with respect to the reference potential GND, which represents the ground potential, is expressed by the following equation (2). In the following equation (2), K is a variable. VN=K⋅Vs+VC

[0021] The variable K in the above equation (2) is expressed by the following equation (3), which is the impedance Z L the load circuit 22, the resistance value R S of the first detection resistor R S_1 and the resistance value R S of the second detection resistor R S_2 used. K=ZL / (2⋅RS+ZL)

[0022] A differential mode voltage VDIFF input to the amplifying circuit 3311 via the first terminal pair 31 and including the voltage value of a common mode noise component is expressed by the following equation (4). VDIFF=VP−VN=(1−K)⋅VS

[0023] Further, a common mode voltage VCOM, which is input to the amplifying circuit 3321 via the second terminal pair 32 and is the voltage of the common mode noise component, is expressed by the following equation (5). VCOM=(VP+VN) / 2={(1+K) / 2}⋅VS+VC

[0024] If the reference potential is the ground potential, the output voltage V OUT1 of the signal amplified by the amplifying circuit 3311 is expressed by the following equation (6), where a differential gain A D , a common mode gain A C , the differential mode voltage V DIFF , the common mode voltage V COM and the variable K. If the common mode voltage V COM depending on the common mode gain A C is amplified, the measurement accuracy of the voltage V deteriorates OUT1between the terminals of the detection resistor due to the relationship represented by the following equation (6). VOUT1=AD⋅VDIFF+AC⋅VCOM=AD⋅(1−K)⋅VS+AC⋅[{(1+K) / 2}⋅VS+VC]

[0025] The positive terminal (+) and the negative terminal (-) of the second terminal pair 32 are short-circuited at the terminal 36. The electrical potential V M of terminal 36 with respect to the earth potential is expressed by the following equation (7). VM={(1+K) / 2}⋅VS+VC

[0026] In the output voltage VOUT2 of the signal amplified by the amplification circuit 3321, the differential mode voltage V DIFF , which is a differential component, 0 (V), and only the common-mode voltage V COM , expressed by the above equation (5), is included as a noise component. Therefore, the output voltage V OUT2expressed by the following equation (8). Since the amplification circuit 3321 and the amplification circuit 3311 have the same circuit configuration, the differential gain A D and the common mode gain A C in the amplification circuit 3321 and in the amplification circuit 3311 are the same size. VOUT2=AD⋅VDIFF+AC⋅VCOM=AC⋅[{(1+K) / 2}⋅VS+VC]

[0027] The analog subtraction circuit 3331 outputs a signal with an output voltage V OUT3 , expressed by the following equation (9), to the control unit 4 by determining the output voltage V OUT2 , expressed by the above equation (8), from the output voltage V OUT1 , expressed by the above equation (6), is subtracted. VOUT3=VOUT1−VOUT2=AD⋅(1−K)⋅VS

[0028] As can be seen from the above equation (9), the component with the common mode voltage V COM, which is related to the common mode gain AC is amplified, from the output voltage V OUT3 of the sensor section 33 compared to the output voltage V OUT1 , which is expressed by the above equation (6), is removed, and the accuracy of the sensor is improved.

[0029] Fig. 5 is a block diagram showing the configuration of a sensor section 33A, which is a variant of the sensor section 33. In Fig. 5 are the same components as in Fig. 3 are provided with the same reference numerals. The sensor section 33A includes a signal measuring circuit 331, a noise measuring circuit 332, and a noise correction circuit 333A. The signal measuring circuit 331 and the noise measuring circuit 332 are identical in their circuit configuration. The noise correction circuit 333A includes an AD converter 3332, an AD converter 3333, and a subtractor 3334.

[0030] The AD converter 3332 converts a detection signal amplified by the signal measuring circuit 331 into a digital signal and outputs the digital signal to the subtractor 3334. The AD converter 3333 converts a detection signal amplified by the noise measuring circuit 332 into a digital signal and outputs the digital signal to the subtractor 3334. The subtractor 3334 subtracts the digital signal, which has a voltage V OUT2 from the digital signal that represents a voltage V OUT1 and thus outputs a digital signal that represents a voltage V OUT1 -V OUT2 to the control unit 4.

[0031] The digital signal converted by AD converter 3332 and the digital signal converted by AD converter 3333 may be filtered before the digital signals are output to subtractor 3334. For example, a filtering process is performed to remove noise components other than differential and common-mode noise components from the digital signals. Subtractor 3334 performs subtraction of the digital signals after the filtering process.

[0032] In the sensor circuit 3 or 3A, the detection resistance is not limited to that formed by the two resistors: the first detection resistance R S_1 and the second detection resistor R S_2 , and the sensing resistor may be a single resistance element or a resistance circuit that is a combination of three or more resistance elements.

[0033] In a case where the electronic device 1 comprises a plurality of circuit sections 2, the sensor circuit 3 or 3A may include a sensing resistor, a first terminal pair, and a second terminal pair for each of the plurality of circuit sections 2. In this case, the sensor circuit 3 or 3A may perform measurements on the plurality of circuit sections 2 simultaneously.

[0034] Furthermore, the sensor section 33 or 33A may be a discrete part independent of the control unit 4, or the sensor section 33 or 33A and the control unit 4 may be a single integrated circuit (IC).

[0035] If wire 23 is a high-speed signal line, sensor circuit 3 or 3A measures the current or voltage in the high-speed signal line. In this case, control unit 4 performs signal analysis in the high-speed signal line based on a signal indicating the current or voltage measured by sensor circuit 3 or 3A.

[0036] As mentioned above, the sensor circuit 3 or 3A according to Embodiment 1 includes: the detection resistor connected to the wire 23; the first terminal pair 31 formed by the lead wires respectively connected to the terminals of the detection resistor; the second terminal pair 32 formed by the lead wires short-circuited together at one terminal of the detection resistor; and the sensor section 33 for measuring the current or voltage from which a noise component is removed using the detection signal supplied thereto via the first terminal pair 31 and the detection signal supplied thereto via the second terminal pair 32. A common-mode noise component is superimposed on the detection signal supplied via the first terminal pair 31 in addition to a differential component representing the true value of the current or voltage in the wire.Since the second terminal pair 32 is mutually short-circuited at one terminal of the detection resistor, only a common-mode noise component is included in the detection signal input through the second terminal pair 32. As a result, the sensor circuit 3 or 3A subtracts the noise component input through the second terminal pair 32 from the detection signal input through the first terminal pair 31, thereby removing an error caused by the noise component from the measured value of the current or voltage in the wire 23.

[0037] In the sensor circuit 3 or 3A according to Embodiment 1, the sensor section 33 or 33A includes: the signal measuring circuit 331 for amplifying the detection signal input to the first terminal pair 31; the noise measuring circuit 332 for amplifying the detection signal input to the second terminal pair 32; and the noise correction circuit 333 for subtracting the value of the detection signal amplified by the noise measuring circuit 332 from the value of the detection signal amplified by the signal measuring circuit 331 and outputting it. The signal measuring circuit 331 and the noise measuring circuit 332 are identical in circuit configuration to each other. With this configuration, the sensor circuit 3 can properly subtract the noise component input to the second terminal pair 32 from the detection signal input to the first terminal pair 31.

[0038] In the sensor circuit 3 according to Embodiment 1, the detection resistor is a series resistance circuit composed of the first detection resistor R S_1 and the second detection resistor R S_2 which are connected in series in the wire 23. The first terminal pair 31 consists of the connecting wires connected to the terminals 34 and 35 of the series resistor circuit, respectively. The second terminal pair 32 consists of the connecting wires short-circuited at the terminal 36, at which the first detection resistor R S_1 and the second detection resistor R S_2 connected in the series resistance circuit. With this configuration, the sensor circuit 3 can properly subtract the noise component input via the second terminal pair 32 from the detection signal input via the first terminal pair 31.

[0039] In the sensor circuit 3A according to Embodiment 1, the detection resistor is a series resistance circuit composed of the first detection resistor R S_1 and the second detection resistor R S_2 which are connected in series between wire 23 and wire 23A. The first terminal pair 31 consists of the connecting wires connected to terminals 37 and 38, respectively, of the series resistor circuit. The second terminal pair 32 consists of the connecting wires connected to terminal 39, a connection point between the first detection resistor R S_1 and the second detection resistor R S_2 in the series resistance circuit, are short-circuited together. With this configuration, it is possible to subtract the noise component input via the second terminal pair 32 from the detection signal input via the first terminal pair 31.

[0040] In the sensor circuit 3 or 3A according to Embodiment 1, the first detection resistor R S_1 and the second detection resistor R S_2 the same resistance value as the first. This allows the sensor circuit 3 to properly subtract the noise component supplied to it via the second terminal pair 32 from the detection signal supplied to it via the first terminal pair 31.

[0041] In the sensor circuit 3 or 3A according to Embodiment 1, the first detection resistor R S_1 and the second detection resistor R S_2 in the wire length of the connecting wire. This allows the sensor circuit 3 to properly subtract the noise component supplied to it via the second terminal pair 32 from the detection signal supplied to it via the first terminal pair 31. Embodiment 2.

[0042] Fig. 6 is a block diagram showing an example of the configuration of the electronic device 1A according to Embodiment 2. In Fig. 6, the electronic device 1A includes a circuit section 2A, a sensor circuit 3, and a control unit 4A. The circuit section 2A includes a three-phase inverter circuit 21A, which is a drive circuit, and a three-phase motor 22A, which is a load circuit, and the inverter circuit 21A and the motor 22A are electrically connected by wires 23U, 23V, and 23W.

[0043] A DC voltage is applied to the inverter circuit 21A via a DC power supply 21B. A positive terminal (+) of the DC power supply 21B is connected to a positive terminal of the DC input of the inverter circuit 21A, and a negative terminal (-) of the DC power supply 21B is connected to a negative terminal of the DC power supply of the inverter circuit. In addition, wires 23U, 23V, and 23W are outputs for outputting currents from the inverter circuit 21A to the motor 22A. Wires 23U, 23V, and 23W can be a wiring pattern on a printed circuit board or conductor cables.

[0044] Further, the inverter circuit 21A includes an upper arm switching element, which is a switching element constituting an upper arm, and a lower arm switching element, which is a switching element constituting a lower arm for each of the phases U, V, and W. The positive terminal of the DC input of the above-mentioned inverter circuit 21A is an input terminal on the upper arm side, and the negative terminal of the DC input of the inverter circuit 21A is an input terminal on the lower arm side.

[0045] The upper arm switching element and the lower arm switching element of each phase are connected in series. Wires 23U, 23V, and 23W, which are the output wires of each phase, are connected to the connection points between them, respectively. The inverter circuit 21A supplies current to the three-phase motor 22A via wires 23U, 23V, and 23W, driving the three-phase motor by switching the upper arm and lower arm switching elements.

[0046] The sensor circuit 3 measures the current values ​​supplied from the three-phase inverter circuit 21A to the three-phase motor 22A. A signal indicating the current value of each phase measured by the sensor circuit 3 is output to the control unit 4A. The control unit 4A controls the drive of the three-phase motor 22A. For example, the control unit 4A controls the drive of the three-phase motor 22A by performing switching control for the switching elements of the upper arm and lower arm based on the current value of each phase measured by the sensor circuit 3. The control unit 4A performs the switching control, for example, using pulse width modulation (PWM).

[0047] The sensor circuit 3 comprises a detection resistor, a first terminal pair and a second terminal pair for each phase, and a sensor section 33B. More specifically, the sensor circuit 3 comprises a first detection resistor R S_1_Uand a second detection resistor R S_2_U connected to the wire 23U, a first terminal pair 31U and a second terminal pair 32U, and also includes a first detection resistor R S_1_V and a second detection resistor R S_2_V which are connected to the wire 23V, a first terminal pair 31V and a second terminal pair 32V, and further comprises a first detection resistor R S_1_W and a second detection resistor R S_2_W which are connected to the wire 23W, a first terminal pair 31W and a second terminal pair 32W.

[0048] The first detection resistor R S_1_U and the second detection resistor R S_2_U form a series resistance circuit connected in two rows to the wire 23U. The first detection resistor R S_1_V and the second detection resistor R S_2_Vform a series resistor circuit connected in two rows to the 23V wire. The first detection resistor R S_1_W and the second detection resistor R S_2_W form a series resistance circuit connected in two rows with the wire 23W.

[0049] The first terminal pair 31U consists of a connecting wire connected to a terminal 34U in the first detection resistor R S_1_U the series resistance circuit, wherein the terminal 34U is connected to the second detection resistor R S_2_U opposite, and a connecting wire connected to a terminal 35U in the second detection resistor R S_2_U , the series resistance circuit, wherein the terminal 35U is connected to the first detection resistor R S_1_U The second terminal pair 32U consists of two connecting wires connected together and short-circuited at a terminal 36U, where the first detection resistor RS_1_U and the second detection resistor R S_2_U are connected.

[0050] The first pair of terminals 31V consists of a connecting wire connected to a terminal 34V in the first detection resistor R S_1_V the series resistor circuit, with the terminal 34V connected to the second detection resistor R S_2_V opposite, and a connecting wire connected to a 35V terminal in the second detection resistor R S_2_V the series resistor circuit, with the terminal 35V connected to the first detection resistor R S_1_V The second pair of terminals 32V consists of two connecting wires that are connected together and short-circuited at a terminal 36V, where the first detection resistor R S_1_V and the second detection resistor R S_2_V are connected.

[0051] The first terminal pair 31W consists of a connecting wire connected to a terminal 34W in the first detection resistor R S_1_W the series resistance circuit, wherein the terminal 34W is connected to the second detection resistor R S_2_W opposite, and a connecting wire connected to a terminal 35W in the second detection resistor R S_2_W the series resistance circuit, with the terminal 35W connected to the first detection resistor R S_1_W The second pair of terminals 32W consists of two connecting wires that are connected together and short-circuited at a terminal 36W, where the first detection resistor R S_1_W and the second detection resistor R S_2_W are connected.

[0052] The sensor section 33B includes, for example, a signal measuring circuit 331, a noise measuring circuit 332, and a noise correction circuit 333, like the sensor section shown in Embodiment 1. In the sensor section 33B, the signal measuring circuit 331 and the noise measuring circuit 332 are also identical in circuit configuration. The signal measuring circuit 331 also includes an amplification circuit 3311 that amplifies each of the current detection signals input through the first terminal pairs 31U, 31V, and 31W, each of which contains noise components. The amplification circuit 3311 amplifies each of the detection signals input through the first terminal pairs 31U, 31V, and 31W, and outputs the amplified signal of each phase to the noise correction circuit 333.

[0053] The noise measurement circuit 332 includes an amplification circuit 3321 and amplifies each of the detection signals input via the second terminal pairs 32U, 32V, and 32W, which contain only the noise components. The amplification circuit 3321 amplifies each of the detection signals supplied to it via the second terminal pairs 32U, 32V, and 32W and outputs the amplified signal of each phase to the noise correction circuit 333. The amplification circuit 3311 and the amplification circuit 3321 are composed of inverting or non-inverting amplification circuits, each using, for example, an operational amplifier.

[0054] The noise correction circuit 333 includes an analog subtraction circuit 3331 and subtracts the value of the detection signal of each phase, amplified by the noise measurement circuit 332, from the value of the detection signal of each phase, amplified by the signal measurement circuit 331. An analog signal indicating the current value of each phase subtracted by the analog subtraction circuit 3331 is output to the control unit 4A. In the signal indicating the current of each phase, which is output from the sensor section 33B to the control unit 4A, a common-mode noise component, amplified with a common-mode gain, is removed. Thus, the sensor circuit 3 improves the measurement accuracy of the currents in the wires 23U, 23V, and 23W.

[0055] Furthermore, the sensor section 33B may include a noise correction circuit 333A instead of the noise correction circuit 333. An AD converter 3332 included in the noise correction circuit 333A converts the detection signal of each phase amplified by the signal measurement circuit 331 into a digital signal and outputs the digital signal to a subtractor 3334 for each phase. An AD converter 3333 converts the detection signal of each phase amplified by the noise measurement circuit 332 into a digital signal and outputs the digital signal to the subtractor 3334 for each phase. The subtractor 3334 subtracts the digital signal of each phase amplified by the noise measurement circuit 332 from the digital signal of each phase amplified by the signal measurement circuit 331, thereby outputting a digital signal, which is a subtraction result, to the control unit 4A.

[0056] The digital signal of each phase converted by AD converter 3332 and the digital signal of each phase converted by AD converter 3333 may be subjected to a filtering process before being output to subtractor 3334. For example, a filtering process is performed in which a noise component other than a differential component and the common-mode noise component are removed from the digital signal of each phase. Subtractor 3334 performs subtraction of the digital signal of each phase after the filtering process.

[0057] In addition, the first terminal pair 31U and the second terminal pair 32U are equal to each other in the wire length of the lead wire. The first terminal pair 31V and the second terminal pair 32V are equal to each other in the wire length of the lead wire. The first terminal pair 31W and the second terminal pair 32W are equal to each other in the wire length of the lead wire. For example, in a case where the first terminal pair 31U is formed by a lead wire (1) connecting the terminal 34U and a positive terminal (+) of the amplification circuit 3311, and a lead wire (2) connecting the terminal 35U and a negative terminal (-) of the amplification circuit 3311, and the second terminal pair 32U is formed by a lead wire (3) and a lead wire (4) short-circuited by the terminal 36U, the lead wires (1) to (4) are equal to each other in the wire length.Between the same phases and between different phases, the wire lengths of the connecting wires forming the first terminal pair and the second terminal pair are equal to each other.

[0058] Fig. Fig. 7 is a block diagram showing the configuration of a sensor circuit 3A, which is a variant of the sensor circuit 3, and shows, as an example, a detection resistor in the phase U. As shown in Fig. 7, the detection resistor included in the sensor circuit 3A may be a series resistor circuit in which a first detection resistor R S_1_U and a second detection resistor R S_2_U connected in series between a wire 23U and a wire 23A. Similarly, in phase V, a sensing resistor is a series resistance circuit in which a first sensing resistor R S_1_V and a second detection resistor R S_2_Vconnected in series between a wire 23V and the wire 23A, and in phase W, a detection resistor is a series resistance circuit in which a first detection resistor R S_1_W and a second detection resistor R S_2_W connected in series between a wire 23W and wire 23A. Wire 23A is connected to a negative terminal (-) of a DC power supply 21B.

[0059] A first terminal pair 31U consists of connecting wires that are connected, respectively, to terminals 37U and 38U of the above-mentioned series resistor circuit. A second terminal pair 32U consists of two connecting wires that are short-circuited at a terminal 39U, to which the first detection resistor R S_1_U and the second detection resistor R S_2_Uconnected in the series resistor circuit mentioned above. The same applies to a first pair of terminals 31V, a second pair of terminals 32V, a first pair of terminals 31W, and a second pair of terminals 32W.

[0060] More specifically, the first pair of terminals 31V consists of connecting wires connected to the 37V and 38V terminals of the series resistor circuit mentioned above. The second pair of terminals 32V consists of two connecting wires shorted to a terminal 39V, where the first sense resistor R S_1_V and the second detection resistor R S_2_Vin the series resistor circuit mentioned above. The first terminal pair 31W consists of connecting wires connected to terminals 37W and 38W, respectively, of the series resistor circuit mentioned above. The second terminal pair 32W consists of two connecting wires short-circuited at a terminal 39W, to which the first detection resistor R S_1_W and the second detection resistor R S_2_W connected in the series resistor circuit mentioned above.

[0061] Fig. Fig. 8 is a block diagram showing the configuration of a variant (1) of the electronic device 1A. In a sensor circuit 3 or 3A, a detection resistor may be a series resistance circuit in which a first detection resistor and a second detection resistor are connected in series with respect to a wire 24 connected between a switching element of the upper arm for each phase and a positive terminal (+) of a DC power supply, as shown in Fig. 8 shown.

[0062] A first terminal pair 31U consists of a connecting wire connected to a terminal 40U in the first detection resistor R S_1_U the series resistance circuit, wherein the terminal 40U is connected to the second detection resistor R S_2_U opposite, and a connecting wire connected to a terminal 41U in the second detection resistor R S_2_Uthe series resistance circuit, wherein the terminal 41U is connected to the first detection resistor R S_1_U A second terminal pair 32U consists of two connecting wires connected together and short-circuited at a terminal 42U, where the first detection resistor R S_1_U and the second detection resistor R S_2_U are connected.

[0063] The same applies to a first pair of terminals 31V, a second pair of terminals 32V, a first pair of terminals 31W and a second pair of terminals 32W, which are shown in Fig. 8 are omitted. More precisely, the first terminal pair 31V consists of a connecting wire connected to a terminal 40V in a first detection resistor R S_1_V a series resistor circuit, the terminal 40V being connected to a second detection resistor R S_2_Vopposite, and a connecting wire connected to a terminal 41V in the second detection resistor R S_2_V the series resistance circuit, with the terminal 41V connected to the first detection resistor R S_1_V The second pair of terminals 32V consists of two connecting wires that are connected together and short-circuited at a terminal 42V, where the first detection resistor R S_1_V and the second detection resistor R S_2_V are connected.

[0064] The first terminal pair 31W consists of a connecting wire connected to a terminal 40W in a first detection resistor R S_1_W a series resistor circuit, wherein the terminal 40W is connected to a second detection resistor R S_2_W opposite, and a connecting wire connected to a terminal 41W in the second detection resistor R S_2_Wthe series resistance circuit, wherein the terminal 41W is connected to the first detection resistor R S_1_W The second pair of terminals 32W consists of two connecting wires that are connected together and short-circuited at a terminal 42W, where the first detection resistor R S_1_W and the second detection resistor R S_2_W are connected.

[0065] A sensor section 33B subtracts detection signals input through the second terminal pairs 32U, 32V, and 32W, each containing only a noise component, from detection signals of current values ​​input through the first terminal pairs 31U, 31V, and 31W, each containing the noise component, thereby removing the noise component (common mode noise component) in the wire 24 of each phase, and measures the current value in the wire 24 of each phase from which the noise component has been removed.

[0066] The electronic device 1A may include, in addition to the detection resistor, the first terminal pair and the second terminal pair associated with each of the Fig. 6 wires 23U, 23V and 23W are connected, the detection resistor, the first pair of terminals and the second pair of terminals, which are connected to the Fig. 8 are connected to the wire 24 of each phase.

[0067] Furthermore, the electronic device 1A may not include the detection resistor, the first terminal pair and the second terminal pair shown in Fig. 6, but may only include the detection resistor, the first terminal pair and the second terminal pair, which are connected to the Fig. 8 shown wire 24 of each phase.

[0068] Also in each electronic device 1A, the sensor circuit 3 or 3A subtracts the noise components supplied to it via the second terminal pairs from the detection signals supplied to it via the first terminal pairs. As a result, the sensor circuit 3 or 3A can remove an error caused by the noise component from the measured value of the current or voltage in each wire comprising the electronic device 1A.

[0069] Fig. Fig. 9 is a block diagram showing the configuration of a variant (2) of the electronic device 1A. In a sensor circuit 3 or 3A, a detection resistor may be a series resistance circuit in which a first detection resistor and a second detection resistor are connected in series with respect to a wire 25 connected between a switching element of the lower arm for each phase and a negative terminal (-) of a DC power supply, as shown in Fig. 9 shown.

[0070] A first terminal pair 31U consists of a connecting wire connected to a terminal 43U in the first detection resistor R S_1_U the series resistance circuit, wherein the terminal 40U is connected to the second detection resistor R S_2_U opposite, and a connecting wire connected to a terminal 44U in the second detection resistor R S_2_U the series resistance circuit, wherein the terminal 44U is connected to the first detection resistor R S_1_U A second pair of terminals 32U consists of two connecting wires connected together and short-circuited at a terminal 45U, where the first detection resistor R S_1_U and the second detection resistor R S_2_U are connected.

[0071] The same applies to a first pair of terminals 31V, a second pair of terminals 32V, a first pair of terminals 31W and a second pair of terminals 32W, which are shown in Fig. 9 can be omitted. More precisely, the first terminal pair 31V consists of a connecting wire connected to a terminal 43V in a first ER S_1_V a series resistor circuit, the terminal 40V being connected to a second detection resistor R S_2_V opposite, and a connecting wire connected to a terminal 44V in the second detection resistor R S_2_V the series resistor circuit, with the terminal 44V connected to the first detection resistor R S_1_V The second pair of terminals 32V consists of two connecting wires that are connected together and short-circuited at a terminal 45V, where the first detection resistor R S_1_V and the second detection resistor R S_2_V are connected.

[0072] The first terminal pair 31W consists of a connecting wire connected to a terminal 43W in a first detection resistor R S_1_W a series resistor circuit, wherein the terminal 40W is connected to a second detection resistor R S_2_W opposite, and a connecting wire connected to a terminal 44W in the second detection resistor R S_2_W the series resistance circuit, wherein the terminal 44W is connected to the first detection resistor R S_1_W The second pair of terminals 32W consists of two connecting wires that are connected together and short-circuited at a terminal 45W, where the first detection resistor R S_1_W and the second detection resistor R S_2_W are connected.

[0073] A sensor section 33B subtracts detection signals input through the second terminal pairs 32U, 32V, and 32W, each containing only a noise component, from detection signals of current values ​​input through the first terminal pairs 31U, 31V, and 31W, each containing the noise component, thereby removing the noise component (common mode noise component) in a wire 25 of each phase, and measures the current value in the wire 25 of each phase from which the noise component has been removed.

[0074] In the Fig. 7, Fig. 8 and Fig. 9, the first terminal pair 31U and the second terminal pair 32U are equal to each other in the wire length of the lead wire. The first terminal pair 31V and the second terminal pair 32V are equal to each other in the wire length of the lead wire. The first terminal pair 31W and the second terminal pair 32W are equal to each other in the wire length of the lead wire. For example, in a case where the first terminal pair 31U is formed by a lead wire (1) connecting the terminal 34U and the positive terminal (+) of the amplifying circuit 3311, and a lead wire (2) connecting the terminal 35U and the negative terminal (-) of the amplifying circuit 3311, and the second terminal pair 32U is formed by a lead wire (3) and a lead wire (4) short-circuited by the terminal 36U, the lead wires (1) to (4) have the same wire length as each other.Between the same phases and between different phases, the wire lengths of the connecting wires forming the first terminal pair and the second terminal pair are equal to each other.

[0075] The electronic device 1A may include, in addition to the detection resistor, the first terminal pair and the second terminal pair associated with each of the Fig. 6 wires 23U, 23V and 23W are connected, the detection resistor, the first pair of terminals and the second pair of terminals, which are connected to the Fig. 9 are connected to the wire 25 of each phase.

[0076] Instead, the electronic device 1A may include, in addition to the detection resistor, the first terminal pair and the second terminal pair associated with each of the Fig. 6 wires 23U, 23V and 23W are connected, the detection resistor, the first terminal pair and the second terminal pair, which are connected to the Fig. 8, and may further include the sensing resistor, the first terminal pair and the second terminal pair connected to the wire 24 of each phase shown in Fig. 9 shown wire 25 of each phase.

[0077] Instead, the electronic device 1A may only include the detection resistor, the first terminal pair and the second terminal pair connected to the Fig. 9 are connected to the wire 24 of each phase.

[0078] Also, in each electronic device 1A, the sensor circuit 3 or 3A subtracts the noise components supplied to it via the second terminal pairs from the detection signals supplied to it via the first terminal pairs. As a result, the sensor circuit 3 or 3A can remove the error caused by the noise component from the measured value of the current or voltage in each wire comprising the electronic device 1A.

[0079] In addition, the sensor circuit 3 or 3A does not need to have the detection resistor, the first terminal pair, and the second terminal pair for each of the wires of all phases, which are the wires 23U, 23V, and 23W, and, for example, the detection resistor, the first terminal pair, and the second terminal pair may be arranged for each of any two phases of the three phases.

[0080] In the sensor circuit 3 or 3A, the detection resistance is not limited to that formed by the two resistors: the first detection resistance R S_1 and the second detection resistor RS_2, and may be a single resistance element or a resistance circuit that is a combination of three or more resistance elements.

[0081] If the electronic device 1A comprises a plurality of circuit sections 2A, the sensor circuit 3 or 3A may include a sensing resistor, a first terminal pair, and a second terminal pair for each of the plurality of circuit sections 2A. In this case, the sensor circuit 3 or 3A may simultaneously perform measurements on the plurality of circuit sections 2A.

[0082] Furthermore, the sensor section 33B may be a discrete part independent of the control unit 4A, or the sensor section 33B and the control unit 4A may be a single integrated circuit (IC).

[0083] As mentioned above, the electronic device 1A according to Embodiment 2 includes: the sensor circuit 3 or 3A; the wires to each of which the detection resistor is connected; the three-phase inverter circuit 21A, which is a drive circuit; and the three-phase motor 22A, which is a load circuit connected to the drive circuit via the wires. The sensor circuit 3A subtracts the noise components supplied to it via the second terminal pairs from the detection signals supplied to it via the first terminal pairs, thereby being able to remove the error caused by the noise component from the measured value of the current or voltage in each of the wires. As a result, the electronic device 1A can perform control of, for example, an operation using the measured value from which the error has been removed.

[0084] In the electronic device 1A according to Embodiment 2, the positive terminal (+) of the DC power supply 21B is connected to the positive terminal of the DC input of the inverter circuit 21A, and the negative terminal (-) of the DC power supply 21B is connected to the negative terminal of the DC input. The series resistance circuit consisting of the first detection resistor and the second detection resistor is connected to the output wires of at least two phases among the output wires 23U, 23V, and 23W of the three phases in the inverter circuit 21A. Each of the first terminal pairs 31U, 31V, and 31W consists of the terminal wires that are respectively connected to the terminals of the series resistance circuit.Each of the second terminal pairs 32U, 32V, and 32W consists of the connecting wires short-circuited at the terminal to which the first detection resistor and the second detection resistor are connected in the series resistance circuit. The sensor circuit 3 subtracts the noise components supplied to it via the second terminal pairs 32U, 32V, and 32W, respectively, from the detection signals supplied to it via the first terminal pairs 31U, 31V, and 31W, and is thereby able to remove the error caused by the noise component from each of the measured values ​​of the currents or voltages in the wires 23U, 23V, and 23W. As a result, the electronic device 1A can perform accurate feedback control for driving the three-phase motor 22A.

[0085] In the electronic device 1A according to Embodiment 2, the positive terminal (+) of the DC power supply 21B is connected to the positive terminal of the DC input of the inverter circuit 21A, and the negative terminal (-) of the DC power supply 21B is connected to the negative terminal of the DC input. Between the output wires of at least two phases among the output wires 23U, 23V, and 23W of the three phases in the inverter circuit 21A and the negative terminal on the wire 23A side connected to the negative terminal (-) of the DC power supply 21B, a series resistance circuit in which the first detection resistor and the second detection resistor are connected in series is connected. Each of the first terminal pairs 31U, 31V, and 31W consists of the terminal wires that are respectively connected to the terminals of the series resistance circuit.Each of the second terminal pairs 32U, 32V, and 32W consists of the connecting wires short-circuited at the terminal to which the first detection resistor and the second detection resistor are connected in the series resistance circuit. The sensor circuit 3A subtracts the noise components supplied to it via the second terminal pairs 32U, 32V, and 32W, respectively, from the detection signals supplied to it via the first terminal pairs 31U, 31V, and 31W, and is thereby able to remove the error caused by the noise component from each of the measured values ​​of the currents or voltages in the wires 23U, 23V, and 23W. As a result, the electronic device 1A can perform accurate feedback control for driving the three-phase motor 22A.

[0086] The electronic device 1A according to Embodiment 2 includes: the three-phase inverter circuit 21A in which the switching elements 211U, 211V, and 211W of the upper arm and the switching elements 212U, 212V, and 212W of the lower arm are connected in series; the DC power supply 21B, whose positive terminal (+) is connected to the positive terminal of the DC input of the inverter circuit 21A and whose negative terminal (-) is connected to the negative terminal of the DC input; and the sensor circuit 3 or 3A having the detection resistors, each of which is connected in series to one of the wires 24 connecting the switching elements 211U, 211V and 211W of the upper arm and the positive terminal (+) of the DC power supply 21B, wherein the first terminal pairs 31U, 31V and 31W each consist of connecting wires each connected to the terminals of a detection resistor, the second terminal pairs 32U, 32V, and 32W,each of which consists of connecting wires shorted to one another at one terminal of a detection resistor, and the sensor section 33B for measuring the current or voltage in the wire 24 of each phase from which the noise component is removed, using the detection signals input thereto via the first terminal pairs 31U, 31V, and 31W and the detection signals input thereto via the second terminal pairs 32U, 32V, and 32W. The sensor circuit 3 or 3A subtracts the noise components input thereto via the second terminal pairs 32U, 32V, and 32W, respectively, from the detection signals input thereto via the first terminal pairs 31U, 31V, and 31W, respectively, and is thereby able to remove the error caused by the noise component from the measured value of the current or voltage in the wire 24 of each phase.

[0087] The electronic device 1A according to Embodiment 2 includes: the three-phase inverter circuit 21A in which the switching elements 211U, 211V, and 211W of the upper arm and the switching elements 212U, 212V, and 212W of the lower arm are connected in series; the DC power supply 21B, whose positive terminal (+) is connected to the positive terminal of the DC input of the inverter circuit 21A and whose negative terminal (-) is connected to the negative terminal of the DC input; and the sensor circuit 3 or 3A having the detection resistors, each of which is connected in series to one of the wires 25 connecting the lower arm switching elements 212U, 212V, and 212W and the negative terminal (-) of the DC power supply 21B, wherein the first terminal pairs 31U, 31V, and 31W each consist of connecting wires each connected to the terminals of a detection resistor, and the second terminal pairs 32U, 32V, and 32W,Each of which is formed by connecting wires short-circuited together at one terminal of a detection resistor, and the sensor section 33B is formed for measuring the current or voltage in the wire 25 of each phase from which the noise component is removed using the detection signals input via the first terminal pairs 31U, 31V, and 31W and the detection signals input via the second terminal pairs 32U, 32V, and 32W. The sensor circuit 3 or 3A subtracts the noise components input to it via the second terminal pairs 32U, 32V, and 32W, respectively, from the detection signals input to it via the first terminal pairs 31U, 31V, and 31W, respectively, and is thereby able to remove the error caused by the noise component from the measured value of the current or voltage in the wire 25 of each phase.

[0088] It is understood that a combination of embodiments is possible, that a change may be made to any component in any of the embodiments, or that any component may be omitted from any of the embodiments. INDUSTRIAL APPLICABILITY

[0089] The sensor circuit according to the present disclosure can be used, for example, in electronic devices having a three-phase inverter circuit and a three-phase motor. LIST OF REFERENCE SYMBOLS

[0090] 1 and 1A: Electronic devices, 2 and 2A: Circuit section, 3 and 3A: Sensor circuit, 4 and 4A: Control unit, 21: Drive circuit, 21A: Inverter circuit, 21B: DC power supply, 22: Load circuit, 22A: Motor, 23, 23U, 23V, 23W, 24 and 25: Wire, 31, 31U, 31V, and 31W: First pair of terminals, 32, 32U, 32V and 32W: Second pair of terminals, 33, 33A and 33B: Sensor section, 34, 34U, 34V, 34W, 35, 35U, 35V, 35W, 36, 36U, 36V, 36W, 37, 37U, 37V, 37W, 38, 38U, 38V, 38W, 39, 39U, 39V, 39W, 40, 40U, 40V, 40W, 41, 41U, 41V, 41W, 42, 42U, 42V, 42W, 43, 43U, 43V, 43W, 44, 44U, 44V, 44W, 45U, 45V, 45W, 211U, 211V and 211W: Upper arm switching element, 212U, 212V and 212W: Lower arm switching element, 331: Signal measuring circuit, 332: Noise measuring circuit, 333 and 333A: Noise correction circuit, 3311 and 3321: amplification circuit, 3331: analog subtraction circuit, 3332 and 3333: AD converter, and 3334: subtractor.

Claims

[1] Sensor circuit (3, 3A) for measuring a current or a voltage in a line of an electronic device with a circuit section (2, 2A) in which a drive circuit (21, 21A) and a load circuit (22, 22A) are connected by one or more lines (23, 23U, 23V, 23W), the sensor circuit (3, 3A) comprising: a resistance for detection (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ) connected to the one or more wires (23, 23U, 23V, 23W); a first pair of terminals (31, 31U, 31V, 31W) comprising connecting wires each connected to the terminals of the resistance (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ) are connected; a second pair of terminals (32, 32U, 32V, 32W) comprising connecting wires connected to a terminal of the detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ) are short-circuited together; and a sensor section (33, 33A, 33B) for measuring the current or voltage from which a noise component is removed, using a detection signal supplied thereto via the first terminal pair (31, 31U, 31V, 31W) and a detection signal supplied thereto via the second terminal pair (32, 32U, 32V, 32W); wherein the detection resistor is a series resistor circuit comprising a first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and a second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) includes wherein the first terminal pair (31, 31U, 31V, 31W) comprises connecting wires each connected to terminals of the series resistance circuit, and where the first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) are connected in series in the line (23) and the second pair of terminals (32, 32U, 32V, 32W) comprises connecting wires which are short-circuited together at a terminal at which the first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) are connected together in the series resistance circuit; or where the first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , RS_2_V , R S_2_W ) are connected in series between two lines (23, 23A) of the plurality of lines connecting the drive circuit and the load circuit, and the second terminal pair comprises connecting wires short-circuited together at a terminal at which the first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) are connected in the series resistor circuit. [2] Sensor circuit (3, 3A) according to claim 1, wherein the sensor section (33, 33A, 33B) comprises: a signal measuring circuit (331) for amplifying the detection signal supplied to it via the first terminal pair (31, 31U, 31V, 31W); a noise measuring circuit (332) for amplifying the detection signal supplied to it via the second terminal pair (32, 32U, 32V, 32W); and a noise correction circuit (333, 333A) for subtracting a value of the detection signal amplified by the noise measuring circuit (332) from a value of the detection signal amplified by the signal measuring circuit (331) and performing an output, wherein the signal measuring circuit (331) and the noise measuring circuit (332) are identical in their circuit configuration. [3] Sensor circuit (3, 3A) according to claim 1, wherein the first detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2 , R S_2_U , R S_2_V , R S_2_W ) have the same resistance value. [4] Sensor circuit (3, 3A) according to claim 1 or 2, wherein the first terminal pair (31, 31U, 31V, 31W) and the second terminal pair (32, 32U, 32V, 32W) have the same wire length of the connecting wires as each other. [5] Electronic device (1, 1A) comprising: the sensor circuit (3, 3A) according to claim 1; the wires (23, 23U, 23V, 23W) to which the detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ) is connected; the drive circuit (21, 21A); and the load circuit (22, 22A) which is connected to the drive circuit (21, 21A) via the wires (23, 23U, 23V, 23W). [6] Electronic device (1A) according to claim 5, wherein the drive circuit comprises a three-phase inverter circuit (21A) and a DC power supply (21B), a positive terminal of the DC power supply (21B) is connected to a positive terminal of the DC input of the inverter circuit (21A), a negative terminal of the DC power supply (21B) is connected to a negative terminal of the DC input of the inverter circuit (21A), from the three-phase wires (23U, 23V, 23W) in the inverter circuit (21A) a series resistance circuit in which a first detection resistance (R S_1_U , R S_1_V , R S_1_W ) and a second detection resistor (R S_2_U , R S_2_V , R S_2_W ) are connected in series, to which at least two-phase wires (23U, 23V, 23W) are connected, the first pair of terminals (31U, 31V, 31W) comprises connecting wires which are each connected to terminals of the series resistance circuit, and the second terminal pair (32U, 32V, 32W) comprises connecting wires which are short-circuited together at a terminal at which the first detection resistor (R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2_U , R S_2_V , R S_2_W ) are connected in the series resistor circuit. [7] Electronic device (1A) according to claim 5, wherein the drive circuit comprises a three-phase inverter circuit (21A) and a DC power supply (21B), a positive terminal of the DC power supply (21B) is connected to a positive terminal of the DC input of the inverter circuit (21A), a negative terminal of the DC power supply (21B) is connected to a negative terminal of the DC input of the inverter circuit (21A), from the three-phase wires (23U, 23V, 23W) in the inverter circuit (21A) a series resistance circuit in which a first detection resistance (R S_1_U , R S_1_V , R S_1_W ) and a second detection resistor (R S_2_U , R S_2_V , R S_2_W ) are connected in series, between at least two-phase wires (23U, 23V, 23W) and a wire on the negative terminal side (23A) connected to the negative terminal of the DC power supply (21B), the first pair of terminals (31U, 31V, 31W) comprises connecting wires which are each connected to terminals of the series resistance circuit, and the second terminal pair (32U, 32V, 32W) comprises connecting wires which are short-circuited together at a terminal at which the first detection resistor (R S_1_U , R S_1_V , R S_1_W ) and the second detection resistor (R S_2_U , R S_2_V , R S_2_W ) are connected in the series resistor circuit. [8] Electronic device (1A) comprising: a three-phase inverter circuit (21A) in which switching elements of the upper arm (211U, 211V, 211W) and switching elements of the lower arm (212U, 212V, 212W) are connected in series; a DC power supply (21B) having a positive terminal connected to a positive terminal of the DC input of the inverter circuit (21A) and a negative terminal connected to a negative terminal of the DC input of the inverter circuit (21A); and a sensor circuit (3A) comprising detection resistors (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ), each of which is connected in series to one of the wires connecting the switching elements of the upper arm (211U, 211V, 211W) and the positive terminal of the DC power supply (21B), first terminal pairs (31U, 31V, 31W), each of which comprises connecting wires each connected to terminals of a detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W), second pairs of terminals (32U, 32V, 32W), each of which comprises connecting wires connected to one another at a terminal of a resistance for detection (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ) are short-circuited, and a sensor section (33B) for measuring currents or voltages in wires from which noise components are removed, using detection signals input via the first terminal pairs (31U, 31V, 31W) and detection signals input via the second terminal pairs (32U, 32V, 32W). [9] Electronic device (1A) comprising: a three-phase inverter circuit (21A) in which switching elements of the upper arm (211U, 211V, 211W) and switching elements of the lower arm (212U, 212V, 212W) are connected in series; a DC power supply (21B) having a positive terminal connected to a positive terminal of the DC input of the inverter circuit (21A) and a negative terminal connected to a negative terminal of the DC input of the inverter circuit (21A); and a sensor circuit (3A) comprising detection resistors (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ), each of which is connected in series with one of the wires connecting the switching elements of the lower arm (212U, 212V, 212W) and the negative terminal of the DC power supply (21B), first terminal pairs (31U, 31V, 31W), each of which comprises connecting wires each connected to terminals of a detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W), second pairs of terminals (32U, 32V, 32W), each of which comprises connecting wires connected to one another at a terminal of a detection resistor (R S_1 , R S_1_U , R S_1_V , R S_1_W , R S_2 , R S_2_U , R S_2_V , R S_2_W ) are short-circuited, and a sensor section (33B) for measuring currents or voltages in wires from which noise components are removed, using detection signals input via the first terminal pairs (31U, 31V, 31W) and detection signals input via the second terminal pairs (32U, 32V, 32W).

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