JP2020038196A - Current sensor, detection device, detection method, and program - Google Patents

Abstract

To solve the problem that deterioration of transition response characteristics in a current sensor includes a case when overshooting occurs and a case when delay occurs and realizing satisfactory transition response characteristics of a magnetic field has been difficult.SOLUTION: A current sensor is provided, which includes a detection part for outputting a signal corresponding to a magnetic field generated by current to be detected flowing through a current path, a reception part for receiving a signal corresponding to the magnetic field, a filtering part for filtering a signal received by the reception part, and an output part for outputting an output signal for indicating a current to be detected according to the filtered signal. The current sensor includes a gain variation band in which a detection gain as a gain of magnetic flux density detected by the detection part is changed following an increase in frequency of the current to be detected, where the filtering part has a gain for canceling a change in a detection gain in at least a partial band of the gain variation band.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a current sensor, a detection device, a detection method, and a program.

2. Description of the Related Art Conventionally, there is known a current detection device including a current detection unit including a current path through which a current flows and a magnetic sensor, and detecting a magnetic field generated by the current with the magnetic sensor (for example, Patent Document 1). Further, in a detection device, a low-pass filter may be used for input of a high-frequency current from a magnetic sensor (for example, Patent Document 2).
Patent Document 1 JP 2005-283451 A Patent Document 2 JP 2013-124875 A

  Such a current detection device may be required to have a good transient response characteristic of a magnetic field in order to detect a transient change in current such as a sharp rise and fall of a current flowing in a current path. However, even when a magnetic sensor having a good transient response characteristic is assembled as a current detection device, operating the current sensor may deteriorate the current measurement characteristics. Such degradation of the transient response characteristic may occur when an overshoot occurs or when a delay occurs, and it has been difficult for the current detection device to achieve a good magnetic field transient response characteristic.

  In order to solve the above problems, in a first aspect of the present invention, a detecting unit that outputs a signal corresponding to a magnetic field generated by a detected current flowing through a current path, and a receiving unit that receives a signal corresponding to the magnetic field And a filter unit for filtering a signal received by the receiving unit, and an output unit for outputting an output signal indicating a current to be detected according to the filtered signal, and a gain of a magnetic flux density detected by the detecting unit. Has a gain variation band that changes with an increase in the frequency of the detected current, and the filter unit has a gain that cancels the change in the detection gain in at least a part of the gain variation band. And provide the program.

  According to a second aspect of the present invention, there is provided a detection method for detecting a current to be detected flowing through a current path, comprising the steps of: receiving a signal corresponding to a magnetic field generated by the detected current; and filtering the received signal. And outputting an output signal indicating the current to be detected according to the filtered signal, wherein the detection gain, which is the gain of the magnetic flux density of the magnetic field, changes with an increase in the frequency of the current to be detected. The step of filtering having a gain fluctuation band includes a step of filtering the signal with a filter having a gain for canceling a change in detection gain in at least a part of the band of the gain fluctuation band.

  According to a third aspect of the present invention, there is provided a detection device for detecting a detected current flowing through a current path, a receiving unit receiving a signal corresponding to a magnetic field generated by the detected current, and a signal received by the receiving unit. And a filter that outputs an output signal indicating the current to be detected in accordance with the filtered signal.The filter includes at least a frequency range in which the gain of the signal with respect to the current to be detected increases. Provided is a detection device having a gain that attenuates with an increase in frequency and becomes unattenuated with a further increase in frequency.

  The above summary of the present invention does not list all of the necessary features of the present invention. Further, a sub-combination of these feature groups can also be an invention.

1 shows a first configuration example of a detection device 100 according to the present embodiment. FIG. 3 is an explanatory diagram illustrating an example of an arrangement of a current path 110 and a magnetic sensor 120. 5 is a graph showing a relationship between a frequency of a current to be detected and a gain of a magnetic flux density detected by a magnetic sensor 120. 7 shows a detection device 400 of a first comparative example. FIG. 9 is an explanatory diagram illustrating a signal gain in the detection device 400 of the first comparative example. 9 shows a detection device 600 of a second comparative example. FIG. 9 is an explanatory diagram illustrating a signal gain in a detection device 600 of a second comparative example. FIG. 3 is an explanatory diagram illustrating a signal gain in the detection device 100 according to the first configuration example. The results of simulating the transient response characteristics to the current pulse input in the detection device 100 of the first configuration example, the detection device 400 of the first comparative example, and the detection device 600 of the second comparative example are shown. FIG. 3 is an explanatory diagram illustrating a signal gain in the detection device 100 according to the first configuration example. 4 shows a flow for detecting a current to be detected in the detection device 100 of the first configuration example. 6 shows a second configuration example of the detection device 700 according to the present embodiment. FIG. 9 is an explanatory diagram illustrating a signal gain in the detection device 100 of the second configuration example. FIG. 9 is an explanatory diagram illustrating a signal gain in the detection device 100 of the second configuration example. 9 shows a third configuration example of the detection device 800 according to the present embodiment. 9 shows a part of a third configuration example of the detection device 800 according to the present embodiment. 9 shows a fourth configuration example of the detection device 900 according to the present embodiment. 5 shows a fifth configuration example of the detection device 1000 according to the present embodiment. 14 illustrates an example of a computer 1900 in which aspects of the embodiments can be wholly or partially embodied.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all combinations of the features described in the embodiments are necessarily essential to the solution of the invention.

  FIG. 1 shows a first configuration example of the detection device according to the present embodiment. The detection device 100 is used as a current sensor that detects a current to be detected flowing through the current path 110. The detection device 100 processes a signal output from the magnetic sensor 120 when the detected current flows through the current path 110, and outputs an output signal indicating the current amount, rising, falling, or the like of the detected current. The detection device 100 includes a current path 110, a magnetic sensor 120, a reception unit 130, a filter unit 140, an amplification unit 150, and an output unit 160. The detection device 100 may be one in which at least one configuration of the detection device 100 is disposed on a substrate and covered with a package made of an insulating material such as resin or ceramic.

  The current path 110 may be, for example, a conductor such as a metal formed on a substrate in a package. In the example of FIG. 1, the current path 110 may be a path through which the current to be detected flows clockwise so as to surround the magnetic sensor 120 when viewed from above in FIG. 1. The cross-sectional shape of the current path 110 in the direction in which the current flows may be a square, a square, a trapezoid, a polygon, a circle, an ellipse, or the like, or a combination thereof. When the detected current flows, the current path 110 generates a clockwise (clockwise) magnetic field around the current path 110 in the direction in which the detected current flows. Thereby, the magnetic field is applied to the magnetic sensor 120 substantially downward.

  The magnetic sensor 120 is arranged near the current path 110 and is connected to the receiving unit 130 by wire or wirelessly. The magnetic sensor 120 is, for example, a Hall element, a magnetoresistive element (MR), a giant magnetoresistive element (GMR), a tunnel effect magnetoresistive element (TMR), a magnetic impedance element (MI element), an inductance sensor, or the like. Including at least one. The magnetic sensor 120 may be housed in the same package as the current path 110. The magnetic sensor 120 may detect a magnetic field generated by the detected current flowing through the current path 110 and output a signal having a current value or a voltage value corresponding to the magnetic field to the receiving unit 130.

  The receiving unit 130 is connected to the filter unit 140. The receiving unit 130 receives a signal corresponding to the magnetic field generated by the detected current from the magnetic sensor 120 and outputs the signal to the filter unit 140. The receiving unit 130 may be a wiring or a terminal for receiving a signal from the magnetic sensor 120.

  The filter unit 140 is connected to the amplifying unit 150 and may include an active filter or a passive filter. The filter unit 140 may perform filtering to reduce the amplitude of the signal received by the reception unit 130 in a predetermined frequency range, and output the signal to the amplification unit 150. The filter section 140 has a gain that attenuates as the frequency increases in at least a part of the frequency range in which the gain of the signal with respect to the detected current increases, and becomes non-attenuated as the frequency further increases.

  The amplification unit 150 is connected to the output unit 160, and may be, for example, an operational amplifier or a comparator. The amplification unit 150 amplifies the signal filtered by the filter unit 140. The amplification unit 150 may amplify the signal amplitude with a predetermined gain and output the signal.

  The output unit 160 outputs an output signal indicating the detected current according to the filtered signal received from the amplification unit 150.

  FIG. 2 is an explanatory diagram showing an example of the arrangement of the current path 110 and the magnetic sensor 120. FIG. 2 shows an arrangement in which the current path 110 surrounds the magnetic sensor 120. In such an arrangement, the current to be detected flows so as to surround the magnetic sensor 120. In FIG. 2, the magnetic sensor 120 and the current path 110 are illustrated as being arranged at the same height (on the same plane). However, the arrangement of the magnetic sensor 120 with respect to the current path 110 may be changed according to the direction of the magnetic sensing axis of the magnetic sensor 120. That is, when an element (such as a Hall element) that detects a magnetic field component in a direction perpendicular to the plane on which the current path 110 is arranged may be used as the magnetic sensor 120, the element may be arranged as shown in FIG. On the other hand, when an element (magnetic resistance element or the like) that detects a magnetic field component in a direction parallel to the plane on which the current path 110 is arranged is used as the magnetic sensor 120, the magnetic sensor 120 is connected to the current path 110. May be arranged above or below the current path 110 in a direction perpendicular to the plane on which the is arranged. The same applies to figures other than FIG. When the frequency of the detected current flowing through the current path 110 increases, the detected current is concentrated on the surfaces 200, 210, and 220 of the current path 110 on the magnetic sensor 120 side by a skin effect. As the current density near the surfaces 200, 210, and 220 of the current path 110 near the magnetic sensor 120 increases, the magnetic flux density detected by the magnetic sensor 120 changes as the magnetic flux when a direct current flows through the current path 110. The magnetic flux density becomes more amplified than the density. Due to the magnetic flux density amplified by the skin effect, an amplified signal indicating a current amount larger than the actual detected current is output from the magnetic sensor 120. The magnetic flux density detected by the magnetic sensor 120 has a remarkable skin effect and increases as the frequency of the detected current increases. When the frequency of the current to be detected further increases, the change in the distribution of the current density in the current path 110 becomes sufficiently small, the gain of the magnetic flux density detected by the magnetic sensor 120 saturates, and the gain of the signal also saturates and becomes constant. Becomes

  Here, in the present application, the gain of the signal with respect to the detected current is the amplification factor of the signal output from the magnetic sensor 120 amplified by the skin effect with respect to the signal corresponding to the amount of current when the DC detected current flows. May be.

  FIG. 3 is a graph showing the relationship between the frequency of the detected current and the gain of the magnetic flux density detected by the magnetic sensor 120. 3, the vertical axis indicates the gain of the magnetic flux density, and the horizontal axis indicates the frequency of the current to be detected. FIG. 3 shows the gain according to the frequency, with the steady-state gain of the detected current being 0. As shown in FIG. 3, the gain of the magnetic flux density detected by the magnetic sensor 120 increases at a frequency within a predetermined range (also referred to as a gain fluctuation band) of the detected current, and becomes saturated and constant at a higher frequency. Has become. The gain of the signal with respect to the current to be detected can change similarly to the gain of the magnetic flux density shown in FIG.

  FIG. 4 shows a detection device 400 of a first comparative example. The detection device 400 shown in FIG. 4 has the same configuration as the detection device 100 of the first configuration example shown in FIG. 1, but does not include the filter unit 140. The description of the same configuration as the detection device 100 of the first configuration example in FIG. 4 is omitted. The detection device 400 of the first comparative example amplifies the signal received by the reception unit 130 by the amplification unit 150 and outputs the signal without performing filtering.

  FIG. 5 is an explanatory diagram illustrating a signal gain in the detection device 400 of the first comparative example. FIG. 5A shows the frequency characteristic of the signal gain due to the skin effect. FIG. 5B shows a frequency characteristic of a gain for amplifying a signal in the amplifying unit 150. FIG. 5C shows the sum of the gain due to the skin effect and the gain in the amplifying section 150 with a solid line, and the dotted line shows the ideal characteristic of the total gain. In FIG. 5, A on the vertical axis indicates the signal gain, and f on the horizontal axis indicates the frequency of the signal.

  In the frequency range in which the signal gain due to the skin effect of FIG. 5A increases, the total gain of FIG. 5C is excessively large. In the detection device 400 of the first comparative example, for example, when a detected current having a steep rising flows through the current path 110, the total gain is in an excessive frequency range while the detected current is changing transiently. The signal is over-amplified and overshoot occurs.

  FIG. 6 shows a detection device 600 of a second comparative example. The detection device 600 of the second comparative example illustrated in FIG. 6 has the same configuration as the detection device 100 of the first configuration example illustrated in FIG. 1, but includes a low-pass filter 610 instead of the filter unit 140. The detection device 600 of the second comparative example uses the low-pass filter 610 to suppress the signal gain due to the skin effect. The description of the same configuration as the detection device 100 of the first configuration example in FIG. 6 is omitted.

  The low-pass filter 610 is connected between the receiving unit 130 and the amplifying unit 150, and reduces a signal from the receiving unit 130 to a frequency equal to or higher than a predetermined frequency and outputs the signal to the amplifying unit 150. The low-pass filter 610 has a gain that attenuates from 0 to a negative value as the frequency increases from a predetermined frequency.

  FIG. 7 is an explanatory diagram illustrating a signal gain in the detection device 600 of the second comparative example. FIG. 7A shows the frequency characteristics of the signal gain due to the skin effect. FIG. 7B shows a frequency characteristic of the gain of the low-pass filter 610. FIG. 7C shows the frequency characteristics of the gain for amplifying the signal in the amplification section 150. FIG. 7D shows the total of the gain due to the skin effect, the gain of the low-pass filter 610, and the gain of the amplifying section 150 by a solid line, and the dotted line shows the ideal characteristic of the total gain. In FIG. 7, A on the vertical axis indicates the signal gain, and f on the horizontal axis indicates the frequency of the signal.

  In the total gain of FIG. 7D, the signal gain by the skin effect of FIG. 7A is reduced by the gain of the low-pass filter 610, but the gain by the skin effect is saturated and becomes constant. In the frequency range, the gain is excessively attenuated and the total gain is reduced. In the detection device 600 of the second comparative example, for example, when a current to be detected having a steep rising flows through the current path 110, the signal has a response waveform in which the high frequency component is smaller than the response waveform of the signal from the magnetic sensor 120. In addition, a response delay of the output from the output unit 160 of the detection device 600 with respect to the output of the magnetic sensor 120 occurs. When the low-pass filter 610 is mounted in the detection device 600 of the second comparative example in order to reduce overshoot, a response delay occurs, and there is a trade-off relationship between overshoot and response speed. Was difficult to achieve.

  FIG. 8 is an explanatory diagram for explaining the signal gain in the detection device 100 of the first configuration example shown in FIG. FIG. 8A shows the frequency characteristics of the signal gain due to the skin effect. FIG. 8B shows the frequency characteristic of the gain of the filter unit 140. FIG. 8C shows the frequency characteristics of the gain for amplifying the signal in the amplification section 150. FIG. 8D shows the total of the gain due to the skin effect, the gain of the filter unit 140, and the gain of the amplifier unit 150 by a solid line, and the dotted line shows the ideal characteristic of the total gain. As illustrated in FIG. 8B, the filter unit 140 of the detection device 100 according to the first configuration example increases the frequency in at least a part of the frequency range x in which the gain due to the skin effect increases from 0 as the frequency increases. A band elimination filter having a gain attenuated from 0 to a negative value and increasing to 0 in a frequency range y larger than a frequency range x in which a signal gain increases due to a skin effect is included.

  The detection device 100 of the first configuration example can cancel the increase in the signal gain due to the skin effect with the attenuating gain in the filter unit 140, for example, when the current to be detected having a steep rising flows through the current path 110, and Shoots can be suppressed. Further, in the detection device 100 of the first configuration example, the gain in the filter unit 140 is not attenuated in a higher frequency range where the gain due to the skin effect is saturated. 120 can be maintained.

  FIG. 9 shows the transient response characteristics to the current pulse input to the current path 110 in the detection device 100 of the first configuration example, the detection device 400 of the first comparative example, and the detection device 600 of the second comparative example. The simulated result is shown. FIG. 9 shows the relationship between the output voltage and time of the detection device 100 of the first configuration example, the detection device 400 of the first comparative example, and the detection device 600 of the second comparative example. In FIG. 9, the vertical axis represents the output voltage of the detection device, and the horizontal axis represents time. In the first comparative example, overshoot has occurred. In the second comparative example, the overshoot can be suppressed, but a response delay occurs. In the first configuration example, the response time characteristic can be maintained while suppressing overshoot.

  FIG. 10 is an explanatory diagram for explaining the signal gain in the detection device 100 of the first configuration example shown in FIG. FIG. 10 shows the gain in the detection device 100 of the first configuration example shown in FIG. 1 as in FIG. 8, except that the gain of the filter unit 140 is different. FIG. 10A shows a frequency characteristic of a signal gain due to the skin effect. FIG. 10B shows the frequency characteristic of the gain of the filter unit 140. FIG. 10C shows frequency characteristics of a gain for amplifying a signal in the amplifying unit 150. FIG. 10D shows the sum of the gain due to the skin effect, the gain of the filter unit 140, and the gain of the amplifier unit 150. In FIG. 10, A on the vertical axis indicates the signal gain, and f on the horizontal axis indicates the frequency of the signal.

  As shown in FIG. 10B, the gain of the filter unit 140 attenuates from 0 to minus as the frequency increases in the frequency range where the signal gain due to the skin effect shown in FIG. 10A increases. Then, the gain has a constant or substantially constant gain in a frequency range y larger than a frequency range in which the gain of the signal increases. In the case of FIG. 10, the frequency range where the gain of the signal due to the skin effect increases and the frequency range where the gain of the filter unit 140 attenuates match, and the minus of the upper limit of the gain of the signal is equal to the lower limit of the gain of the filter unit 140. Since they match, the gain of the filter unit 140 is line-symmetric with the gain due to the skin effect shown in FIG. As a result, in the entire frequency range, the gain of the signal due to the skin effect is canceled by the gain of the filter unit 140, and the gain of the amplification unit 150 in FIG. 10C and the total gain of FIG. I do.

  The detection device 100 including the filter unit 140 having such a gain can obtain an ideal signal according to the gain of the amplifier unit 150 in all frequency ranges, and suppresses overshoot and has a response time characteristic. Can be maintained. The gain of the signal due to the skin effect shown in (a) of FIGS. 5, 7, 8, and 10 indicates a difference (for example, the unit is dB) from the gain of the signal when a DC detected current is flowing. May be something.

  FIG. 11 shows a flow of detecting the current to be detected in the detection device 100 of the first configuration example. The detecting device 100 starts detecting the detected current when the power of the detecting device 100 is turned on or when the detected current flows through the current path 110.

  In S11, the magnetic sensor 120 outputs a signal corresponding to a magnetic field generated by the detected current flowing through the current path 110. The signal output from the magnetic sensor 120 may have a larger current amount as the detected magnetic field is larger, and may have a smaller current amount as the detected magnetic field is smaller.

  In S12, the filter unit 140 filters the signal received by the reception unit 130 from the magnetic sensor 120 so as to decrease the signal in a predetermined frequency range. The filter unit 140 may cancel at least a part of the increased portion of the gain of the signal output from the magnetic sensor 120 with respect to the detected current, which is caused by the skin effect. Filter section 140 may have a gain that attenuates in at least a portion of the frequency range corresponding to the increasing portion. Further, filter section 140 may have a constant gain or an increasing gain in a frequency range higher than the frequency range corresponding to the increasing portion.

  In the frequency characteristic of the signal gain due to the skin effect shown in FIG. 8A, the filter unit 140 has at least a part of the frequency range x in which the signal gain increases from 0 to a constant value until the signal gain becomes constant. , 0 to a negative value. As an example, the filter unit 140 may have a gain that attenuates with an increase in frequency in a frequency range of a signal of 10 kHz to 10 MHz and is not attenuated in a frequency range higher than 10 MHz. The lower limit of the gain of the filter unit 140 may be equal to or less than the negative value of the upper limit of the gain caused by the skin effect.

  Here, the frequency characteristic of the gain of the signal due to the skin effect may differ depending on at least one of the shape and material of the current path 110 and the arrangement relationship between the current path 110 and the magnetic sensor 120. Therefore, for example, in the calibration of the detection device 100 or when the power supply of the detection device 100 is turned on, the frequency characteristic of the signal gain as shown in FIG. 8A may be calculated in advance. Thereby, the filter unit 140 may have a gain determined according to the frequency characteristic of the previously calculated gain.

  In S13, the amplification unit 150 amplifies the filtered signal with a predetermined gain. Amplifying section 150 may amplify a signal in a predetermined frequency range with a gain greater than zero.

  In S14, the output unit 160 outputs an output signal indicating the current to be detected. The output unit 160 may output the signal as it is. The output unit 160 may output an output signal indicating the current value of the signal or an output signal indicating the result of comparing the signal with a threshold (for example, 0 or 1, low or high). The detecting device 100 performs a detecting operation when the detected current stops flowing through the current path 110, when the amount of current of the signal output from the magnetic sensor 120 becomes 0, or when the power of the detecting device 100 is turned off. May be terminated.

  The detection device 100 according to the present embodiment can adjust the gain of the entire detection device 100 in the filter unit 140 to suppress overshoot and maintain good transient response characteristics of the magnetic field.

  FIG. 12 shows a second configuration example of the detection device 700 according to the present embodiment. The detection device 700 shown in FIG. 12 has the same configuration as the detection device 100 of the first configuration example shown in FIG. 1, except that the positional relationship between the current path 110 of the current detection unit and the magnetic sensor 120 is different. That is, in FIG. 12, the current path 110 has a bent portion, and the magnetic sensor 120 is disposed outside the bent portion. In such a positional relationship, when the frequency of the current to be detected increases, the magnetic flux density detected by the magnetic sensor 120 due to the skin effect becomes smaller than the magnetic flux density when a DC current flows through the current path 110. Density. This is because the gain increases due to the skin effect in the positional relationship where the magnetic sensor 120 as shown in FIG. 2 is arranged inside the bent portion of the current path 110, and therefore, the position outside the region surrounded by the current path 110 is increased. It is clear that the gain is attenuated when the magnetic sensor 120 is disposed in the first position. Due to the magnetic flux density attenuated by the skin effect, an attenuated signal indicating a current amount smaller than the actual detected current is output from the magnetic sensor 120. The magnetic flux density detected by the magnetic sensor 120 has a remarkable skin effect and decreases as the frequency of the detected current increases. When the frequency of the current to be detected further increases, the change in the distribution of the current density in the current path 110 becomes sufficiently small, the gain of the magnetic flux density detected by the magnetic sensor 120 saturates, and the gain of the signal also saturates and becomes constant. Becomes

  As described above, since the detection gain, which is the gain of the magnetic flux density detected by the magnetic sensor 120, has a gain variation band that changes with an increase in the frequency of the current to be detected, the filter unit 140 includes at least the gain variation band. It has a gain that cancels the change in detection gain in some bands. In the detection device 100 of the first configuration example, since the detection gain in the gain fluctuation band increases with an increase in the frequency of the detected current, the filter unit 140 is configured to detect at least a part of the gain fluctuation band. It has a gain that attenuates with increasing frequency and becomes unattenuated with further increasing frequency. On the other hand, in the detection device 100 of the second configuration example, the detection gain in the gain variation band is attenuated with an increase in the frequency of the current to be detected. Has a gain that amplifies as the frequency increases and becomes non-amplified as the frequency further increases.

  The filter section 140 of the first configuration example and the filter section 140 of the second configuration example may have the same configuration except for the gain. The filter unit 140 includes, for example, at least one of a band elimination filter, an active filter, a passive filter, an analog filter, and a digital filter having the above-described gain.

  Here, in the present application, the gain of the signal with respect to the detected current is the amplification factor of the signal output from the magnetic sensor 120 attenuated by the skin effect with respect to the signal corresponding to the current amount when the DC detected current flows. May be. Note that the detection unit of the present application may include the magnetic sensor 120 in each embodiment.

  FIG. 13 is an explanatory diagram illustrating a signal gain in the detection device 700 of the second configuration example illustrated in FIG. FIG. 13A shows a frequency characteristic of a signal gain due to the skin effect. FIG. 13B shows a frequency characteristic of the gain of the filter unit 140. FIG. 13C shows frequency characteristics of a gain for amplifying a signal in the amplifying unit 150. FIG. 13D shows the total of the gain due to the skin effect, the gain of the filter unit 140, and the gain of the amplifier unit 150 by a solid line, and the dotted line shows the ideal characteristic of the total gain. As shown in FIG. 13B, the filter unit 140 of the detection device 700 according to the second configuration example has the frequency in at least a part of the frequency range x (gain fluctuation band) where the gain due to the skin effect attenuates from 0. Has a gain that increases from 0 to a positive value with an increase in frequency, and attenuates to 0 in a frequency range y larger than a frequency range x in which the signal gain attenuates due to the skin effect. In FIG. 13, A on the vertical axis indicates the signal gain, and f on the horizontal axis indicates the frequency of the signal.

  In the detection device 700 of the second configuration example, for example, when a detected current having a steep rising flows through the current path 110, the attenuation of the signal gain due to the skin effect can be canceled by the increasing gain in the filter unit 140, and the response Delay can be suppressed. Further, in the detection device 700 of the second configuration example, the gain in the filter unit 140 does not increase in a higher frequency range where the gain due to the skin effect is saturated. 120 can be maintained.

  FIG. 14 is an explanatory diagram for explaining the signal gain in the detection device 700 of the second configuration example shown in FIG. FIG. 14 shows the gain in the detection device 700 of the second configuration example shown in FIG. 12 as in FIG. 13 except that the gain of the filter unit 140 is different. FIG. 14A shows the frequency characteristics of the signal gain due to the skin effect. FIG. 14B shows the frequency characteristics of the gain of the filter unit 140. FIG. 14C shows frequency characteristics of a gain for amplifying a signal in the amplifying unit 150. FIG. 14D shows the sum of the gain due to the skin effect, the gain of the filter unit 140, and the gain of the amplifier unit 150. In FIG. 14, A on the vertical axis indicates the signal gain, and f on the horizontal axis indicates the frequency of the signal.

  As shown in FIG. 14B, the gain of the filter unit 140 increases with the frequency in the frequency range (gain fluctuation band) in which the signal gain is attenuated due to the skin effect shown in FIG. It has a gain that increases from 0 to a positive value and becomes constant or substantially constant in a frequency range y larger than a frequency range in which the gain of the signal attenuates. In the case of FIG. 14, the frequency range in which the gain of the signal due to the skin effect is attenuated matches the frequency range in which the gain of the filter unit 140 increases, and the absolute value of the lower limit of the signal gain is equal to the upper limit of the gain of the filter unit 140. Therefore, the gain of the filter unit 140 is line-symmetric with the gain due to the skin effect shown in FIG. Thus, in all frequency ranges, the gain of the signal due to the skin effect is canceled by the gain of the filter unit 140, and the total gain of the amplification unit 150 in FIG. 14C and the total gain of FIG. I do.

  The detection device 700 including the filter unit 140 having such a gain can obtain an ideal signal according to the gain of the amplifier unit 150 in all frequency ranges, and suppresses a response delay while maintaining an overshoot characteristic. Can be maintained. Note that the signal gain due to the skin effect shown in FIG. 13 and FIG. 14A indicates a difference (for example, the unit is dB) from the signal gain when a DC detected current is flowing. Good.

  FIG. 15 shows a third configuration example of the detection device 800 according to the present embodiment. The detection device 800 shown in FIG. 15 has the same configuration as the detection device 100 of the first configuration example shown in FIG. 1, except that the current paths 110a and 110b, the magnetic sensors 120a and 120b, the reception units 130a and 130b, A plurality of filter units 140a and 140b are provided.

  Each of the plurality of current paths 110a and 110b may be the same as the current path 110 of the detection device 100 of the first configuration example. The plurality of current paths 110a and 110b are not electrically connected to each other, and may individually pass a current to be detected. In addition, the plurality of current paths 110a and 110b may be electrically connected to each other, and may have the same current to be detected.

  Each of the plurality of magnetic sensors 120a and 120b may be the same as the magnetic sensor 120 of the detection device 100 of the first configuration example. The plurality of magnetic sensors 120a and 120b are arranged near the current paths 110a and 110b to be detected, respectively. The plurality of magnetic sensors 120a, 120b may output a signal corresponding to the magnetic field around the current paths 110a, 110b symmetrical to the respective detections.

  Each of the receiving units 130a and 130b may be the same as the receiving unit 130 of the detection device 100 of the first configuration example.

  Each of the plurality of filter units 140a and 140b may be the same as the filter unit 140 of the detection device 100 of the first configuration example. Further, one or both of them may be the same as the filter unit 140 of the second configuration example. The detection device 800 of the third configuration example may individually process signals output from the plurality of filters 140a and 140b, or may process signals output from the plurality of filters 140a and 140b together.

  The detection device 800 of the third configuration example includes a plurality of filters each having a different gain for each configuration even when there are a plurality of sets of current paths and magnetic sensors and their positional relationships are different. The signal can be processed by the section, and the input signal having good response characteristics can be transmitted to the amplification section.

  FIG. 16 is an explanatory diagram showing an example of the arrangement of the current path 110 and the magnetic sensor 120 in the detection device 800 of the third configuration example according to the present embodiment. When two magnetic sensors 120a and 120b are installed in one current path 110 in the detection device 800 of the third configuration example, as shown in FIG. They may be arranged to face each other with 110 interposed therebetween. In addition, according to the direction of the magnetic sensing axis of the magnetic sensors 120a and 120b, the plurality of magnetic sensors 120a and 120b sandwich the current path 110 in a cross-sectional view (for example, in a direction perpendicular to a surface on which the current path 110 is arranged). They may be arranged to face each other (above and below the current path 110). In this case, the filter unit 140a that processes the signal from the magnetic sensor 120a has the same gain as the filter unit 140 of the detection device 100 of the first configuration example, and the filter unit 140b that processes the signal from the magnetic sensor 120b is , May have the same gain as the filter unit 140 of the detection device 100 of the second configuration example. As described above, in the detection device 800 of the present embodiment, it is preferable that each of the plurality of filter units 140 has a gain according to the positional relationship between the corresponding magnetic sensor 120 and the current path 110.

  FIG. 17 shows a fourth configuration example of the detection device 900 according to the present embodiment. The detection device 900 shown in FIG. 17 has the same configuration as the detection device 100 of the first configuration example shown in FIG. 1, except that the current paths 110a and 110b, the magnetic sensors 120a and 120b, the amplification units 150a and 150b, , And a chopper circuit 710 and a correction unit 720.

  Each of the plurality of current paths 110a and 110b may be the same as the current path 110 of the detection device 100 of the first configuration example. The plurality of current paths 110a and 110b are not electrically connected to each other, and may individually pass a current to be detected. In addition, the plurality of current paths 110a and 110b may be electrically connected to each other, and may have the same current to be detected.

  Each of the plurality of magnetic sensors 120a and 120b may be the same as the magnetic sensor 120 of the detection device 100 of the first configuration example. The plurality of magnetic sensors 120a and 120b are arranged near the current paths 110a and 110b to be detected, respectively. The plurality of magnetic sensors 120a, 120b may output a signal corresponding to the magnetic field around the current paths 110a, 110b symmetrical to the respective detections. The detection device 900 of the fourth configuration example may individually process signals output from the plurality of magnetic sensors 120a and 120b, or may process signals output from the plurality of magnetic sensors 120a and 120b together. Good.

  The amplification units 150a and 150b may be the same as the amplification unit 150 of the detection device 100 of the first configuration example. The amplification unit 150a is connected between the reception unit 130 and the filter unit 140, and amplifies a signal from the reception unit 130 and outputs the signal to the filter unit 140. The amplification unit 150b is connected between the filter unit 140 and the output unit 160, and amplifies the filtered signal and outputs the amplified signal to the output unit 160.

  The chopper circuit 710 is connected between the magnetic sensors 120a and 120b and the receiving unit 130, and choppers signals output from the magnetic sensors 120a and 120b. The chopper circuit 710 may receive a signal output by chopper driving each of the magnetic sensors 120a and 120b. For example, the chopper circuit 710 may switch the direction of the drive current of the Hall element included in each of the magnetic sensors 120a and 120b between the 0 degree direction and the 90 degree direction at the chopper frequency. The chopper circuit 710 calculates a difference between signals in the 0-degree direction and the 90-degree direction output from the magnetic sensors 120a and 120b, removes an offset voltage, and outputs a processed signal to the receiving unit 130. May be.

  The correction unit 720 is connected to the amplification units 150a and 150b and the filter unit 140, and corrects a signal. The correction unit 720 may correct the setting by correcting the settings of the amplification units 150a and 150b and the filter unit 140. The correction unit 720 may, for example, correct the gains of the amplification units 150a and 150b and the filter unit 140, respectively, to adjust the gain to a signal having a desired current value.

  In the detection device 900 having such a fourth configuration example, the offset or noise of the magnetic sensor 120 can be efficiently reduced by the chopper circuit 710, and the signal amplified by the correction unit 720 at a desired amplification factor can be obtained. Thus, overshoot can be suppressed and good transient response characteristics of the magnetic field can be maintained.

  Note that one or more amplifying sections 150 may be arranged in only one of the preceding and succeeding stages of filter section 140, or a plurality of amplifying sections 150 may be arranged on both sides of the preceding and succeeding stages. In the present application, “gain” may be expressed in units of dB, for example.

  FIG. 18 shows a fifth configuration example of the detection device 1000 according to the present embodiment. The detection device 1000 shown in FIG. 18 has the same configuration as the detection device 100 of the first configuration example shown in FIG. 1, but includes an A / D unit 170 that converts an analog signal into a digital signal. The filter unit 140 may be located before or after the A / D unit 170.

  In the detection apparatus 1000 of the fifth configuration example, the filter section 140 suppresses overshoot in all frequency ranges, and maintains the response time characteristics, and also performs the analog / digital conversion of the digital by the A / D section 170. The signal can be output from the output unit 160.

  When the filter section 140 is arranged in a stage preceding the A / D section 170, the overshoot due to the skin effect is reduced by the filter section 140, and an ideal signal according to the gain of the amplifier section 150 is transmitted to the A / D section 170. Therefore, the input range of the A / D unit 170 can be reduced.

  When the filter section 140 is arranged after the A / D section 170 as shown in FIG. 18, the filter section 140 may be a digital filter. In the case of this digital filter, it is not necessary to consider that the characteristics of the filter section vary due to temperature and element variations. Note that the detection devices in all the embodiments may be current sensors.

  Various embodiments of the present invention may be described with reference to flowcharts and block diagrams, wherein blocks represent (1) steps in a process in which an operation is performed or (2) devices responsible for performing an operation. Section. Certain stages and sections are implemented by dedicated circuitry, programmable circuitry provided with computer readable instructions stored on computer readable media, and / or processors provided with computer readable instructions stored on computer readable media. May be. Dedicated circuits may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. Programmable circuits include logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, memory elements such as flip-flops, registers, field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), etc. And the like, and may include reconfigurable hardware circuits.

  Computer readable media may include any tangible device capable of storing instructions for execution by a suitable device, such that computer readable media having instructions stored thereon is specified in a flowchart or block diagram. Product comprising instructions that can be executed to create a means for performing the specified operation. Examples of the computer readable medium may include an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, and the like. More specific examples of computer readable media include floppy disks, diskettes, hard disks, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), Electrically erasable programmable read only memory (EEPROM), static random access memory (SRAM), compact disk read only memory (CD-ROM), digital versatile disk (DVD), Blu-ray (RTM) disk, memory stick, integrated A circuit card or the like may be included.

  The computer readable instructions may be assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state setting data, or object oriented programming such as Smalltalk, JAVA, C ++, etc. Source or object code written in any combination of one or more programming languages, including conventional procedural programming languages, such as the language, Python, and the "C" programming language or similar programming languages. May include.

  The computer readable instructions may be directed to a general purpose computer, special purpose computer, or other programmable data processing device processor or programmable circuit, either locally or over a wide area network (WAN) such as a local area network (LAN), the Internet, or the like. ) May be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, and the like.

  FIG. 19 illustrates an example of a computer 1900 in which aspects of the invention may be wholly or partially implemented. The programs installed on the computer 1900 can cause the computer 1900 to function as one or more sections of the operation or the device associated with the device according to the embodiment of the present invention, or the operation or the one or more of the one or more devices. Sections may be executed and / or computer 1900 may execute a process or steps of a process according to an embodiment of the present invention. Such programs may be executed by CPU 2000 to cause computer 1900 to perform certain operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

  A computer 1900 according to the present embodiment is connected to a host computer 2082 including a CPU 2000, a RAM 2020, a graphic controller 2075, and a display device 2080, which are mutually connected by a host controller 2082, and an input / output controller 2084 to the host controller 2082. Input / output unit having a communication interface 2030, a hard disk drive 2040, and a DVD drive 2060, and a legacy input / output unit having a ROM 2010, a flash memory drive 2050, and an input / output chip 2070 connected to an input / output controller 2084. .

  The host controller 2082 connects the RAM 2020 to the CPU 2000 and the graphic controller 2075 that access the RAM 2020 at a high transfer rate. The CPU 2000 operates based on programs stored in the ROM 2010 and the RAM 2020, and controls each unit. The graphic controller 2075 acquires image data generated by the CPU 2000 or the like on a frame buffer provided in the RAM 2020, and displays the image data on the display device 2080. Alternatively, the graphic controller 2075 may include a frame buffer for storing image data generated by the CPU 2000 or the like.

  The input / output controller 2084 connects the host controller 2082 to the communication interface 2030, the hard disk drive 2040, and the DVD drive 2060, which are relatively high-speed input / output devices. The communication interface 2030 communicates with another device via a network by wire or wirelessly. The communication interface functions as hardware for performing communication. The hard disk drive 2040 stores programs and data used by the CPU 2000 in the computer 1900. The DVD drive 2060 reads a program or data from the DVD 2095 and provides it to the hard disk drive 2040 via the RAM 2020.

  In addition, the input / output controller 2084 is connected to the ROM 2010, the flash memory drive 2050, and the relatively low-speed input / output device of the input / output chip 2070. The ROM 2010 stores a boot program executed by the computer 1900 at the time of startup, and / or a program depending on hardware of the computer 1900. The flash memory drive 2050 reads a program or data from the flash memory 2090 and provides it to the hard disk drive 2040 via the RAM 2020. The input / output chip 2070 connects the flash memory drive 2050 to the input / output controller 2084 and inputs / outputs various input / output devices via, for example, a parallel port, a serial port, a keyboard port, a mouse port, and the like. Connect to controller 2084.

  The program provided to the hard disk drive 2040 via the RAM 2020 is stored in a recording medium such as a flash memory 2090, a DVD 2095, or an IC card and provided by a user. The program is read from the recording medium, installed on the hard disk drive 2040 in the computer 1900 via the RAM 2020, and executed by the CPU 2000. The information processing described in these programs is read by the computer 1900 and provides for cooperation between the software and the various types of hardware resources described above. An apparatus or method may be configured for implementing manipulation or processing of information according to the use of computer 1900.

  As an example, when performing communication between the computer 1900 and an external device or the like, the CPU 2000 executes a communication program loaded on the RAM 2020, and executes a communication interface based on the processing content described in the communication program. The communication processing is instructed to 2030. Under the control of the CPU 2000, the communication interface 2030 reads out transmission data stored in a transmission buffer area provided on a storage device such as the RAM 2020, the hard disk drive 2040, the flash memory 2090, or the DVD 2095, and transmits the data to the network. Alternatively, it writes the received data received from the network to a reception buffer area or the like provided on the storage device. As described above, the communication interface 2030 may transfer the transmission / reception data to / from the storage device by the DMA (Direct Memory Access) method, and instead, the CPU 2000 may use the transfer source storage device or the communication interface 2030. The data may be read from the communication interface 2030 or the data may be written to the communication interface 2030 or the storage device of the transfer destination to transfer the transmission and reception data.

  Further, the CPU 2000 transfers all or a necessary part from a file or a database stored in an external storage device such as a hard disk drive 2040, a DVD drive 2060 (DVD 2095), or a flash memory drive 2050 (flash memory 2090) to a DMA. The data is read into the RAM 2020 by transfer or the like, and various processes are performed on the data on the RAM 2020. Then, the CPU 2000 writes the processed data back to the external storage device by DMA transfer or the like. In such a process, the RAM 2020 can be regarded as temporarily holding the contents of the external storage device. Therefore, in this embodiment, the RAM 2020 and the external storage device are collectively referred to as a memory, a storage unit, or a storage device.

  Various information such as various programs, data, tables, and databases in the present embodiment are stored on such a storage device and are subjected to information processing. Note that the CPU 2000 can also hold a part of the RAM 2020 in a cache memory and perform reading and writing on the cache memory. Even in such a form, the cache memory plays a part of the function of the RAM 2020. Therefore, in the present embodiment, the cache memory is also included in the RAM 2020, the memory, and / or the storage device unless otherwise indicated. I do.

  In addition, the CPU 2000 performs various calculations, information processing, condition determination, information search / replacement, and the like described in the present embodiment on the data read from the RAM 2020, as specified by the instruction sequence of the program. And write it back to the RAM 2020. For example, when performing the condition determination, the CPU 2000 determines whether the various variables described in the present embodiment satisfy conditions such as larger, smaller, greater than, less than, equal to, and the like as compared with other variables or constants. Then, if the condition is satisfied (or not satisfied), a branch is made to a different instruction sequence or a subroutine is called.

  Further, the CPU 2000 can search for information stored in a file or a database in the storage device. For example, in the case where a plurality of entries in which the attribute value of the second attribute is associated with the attribute value of the first attribute are stored in the storage device, the CPU 2000 determines whether the plurality of entries stored in the storage device By searching for an entry in which the attribute value of the first attribute matches the specified condition and reading the attribute value of the second attribute stored in the entry, the entry is associated with the first attribute satisfying the predetermined condition. The attribute value of the obtained second attribute can be obtained.

  Further, when a plurality of elements are listed in the description of the embodiment, elements other than the listed elements may be used. For example, if "X performs Y using A, B, and C", X may perform Y using D in addition to A, B, and C.

  As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various changes or improvements can be made to the above embodiment. It is apparent from the description of the appended claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The execution order of each processing such as operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before”, “before”. It should be noted that they can be realized in any order as long as the output of the previous process is not used in the subsequent process. Even if the operation flow in the claims, the specification, and the drawings is described using “first,” “second,” or the like for convenience, it means that it is essential to perform the operation in this order. Not something.

REFERENCE SIGNS LIST 100 detection device 110 current path 120 magnetic sensor 130 reception unit 140 filter unit 150 amplification unit 160 output unit 170 A / D unit 200 surface 210 surface 220 surface 400 detection device 600 detection device 610 low-pass filter 700 detection device 710 chopper circuit 720 correction unit 800 detection device 900 detection device 1000 detection device 1900 computer 2000 CPU
2010 ROM
2020 RAM
2030 Communication interface 2040 Hard disk drive 2050 Flash memory drive 2060 DVD drive 2070 Input / output chip 2075 Graphic controller 2080 Display device 2082 Host controller 2084 Input / output controller 2090 Flash memory 2095 DVD

Claims (23)

A detection unit that outputs a signal corresponding to a magnetic field generated by the detected current flowing through the current path,
A receiving unit that receives a signal corresponding to the magnetic field,
A filter unit for filtering the signal received by the receiving unit,
An output unit that outputs an output signal indicating the current to be detected according to the filtered signal;
With
The detection gain, which is the gain of the magnetic flux density detected by the detection unit, has a gain variation band that changes with an increase in the frequency of the detected current,
The current sensor, wherein the filter unit has a gain that cancels a change in the detection gain in at least a part of the gain fluctuation band. The detection gain in the gain fluctuation band increases with an increase in the frequency of the detected current,
2. The current sensor according to claim 1, wherein the filter unit has a gain that attenuates with an increase in frequency in at least a part of the gain fluctuation band and becomes unattenuated with a further increase in frequency. The current sensor according to claim 2, wherein the filter unit has a constant gain or a gain that increases to 0 dB in a frequency range larger than the at least a part of the frequency range of the gain variation band. The current sensor according to claim 2, wherein the filter unit has a gain that attenuates as the frequency increases in a frequency range of 10 kHz to 10 MHz. In the gain variation band, the detection gain attenuates with an increase in the frequency of the detected current,
2. The current sensor according to claim 1, wherein the filter unit has a gain that amplifies with an increase in frequency in at least a part of the gain fluctuation band and becomes non-amplifier with a further increase in frequency. The current sensor according to claim 5, wherein the filter section has a constant gain or a gain that attenuates to 0 dB in a frequency range larger than the at least a part of the frequency range of the gain variation band. The current sensor according to claim 5, wherein the filter unit has a gain that amplifies as the frequency increases in a frequency range of 10 kHz to 10 MHz. The current sensor according to any one of claims 1 to 7, further comprising one or more amplifying units that amplify the signal that is filtered by the filter unit. Comprising a plurality of amplifiers for amplifying the signal,
The current sensor according to any one of claims 1 to 7, wherein the filter unit is disposed between the plurality of amplifying units. The current sensor according to claim 1, wherein the filter unit includes a band elimination filter having the gain. The current sensor according to any one of claims 1 to 10, wherein the filter unit includes an active filter or a passive filter having the gain. The current sensor according to claim 1, wherein the filter unit includes an analog filter or a digital filter having the gain. The current sensor according to any one of claims 1 to 12, wherein the detection unit includes a magnetic sensor that is built in the same package as the current path and outputs the signal to the reception unit. The current sensor according to claim 13, wherein the detection unit includes a plurality of the magnetic sensors.   The current sensor according to claim 14, further comprising: a plurality of the filter units having gains different from each other with respect to the plurality of magnetic sensors. The current sensor according to claim 14 or 15, wherein the plurality of magnetic sensors are arranged to face each other across the current path in plan view.
The magnetic sensor includes a Hall element, a magnetoresistive element (MR), a giant magnetoresistive element (GMR), a tunnel effect magnetoresistive element (TMR), a magnetic impedance element (MI element), or an inductance sensor. The current sensor according to any one of the above. The current sensor according to claim 1, further comprising a correction unit configured to correct the signal. The current sensor according to any one of claims 1 to 18, further comprising a chopper circuit that choppers the signal. The current sensor according to claim 1, further comprising an AD conversion circuit that converts the signal into a digital signal and outputs the digital signal.   A program for causing a computer to function as the current sensor according to any one of claims 1 to 20. A detection method for detecting a detected current flowing through a current path,
Receiving a signal corresponding to the magnetic field generated by the detected current,
Filtering the received signal;
Outputting an output signal indicating the detected current in response to the filtered signal;
With
The detection gain, which is the gain of the magnetic flux density of the magnetic field, has a gain variation band that changes with an increase in the frequency of the detected current,
The filtering method includes filtering the signal with a filter having a gain that cancels the change in the detection gain in at least a part of the gain fluctuation band. A detection device for detecting a detected current flowing through a current path,
A receiving unit that receives a signal corresponding to a magnetic field generated by the detected current,
A filter unit for filtering the signal received by the receiving unit,
An output unit that outputs an output signal indicating the detected current according to the filtered signal.
With
A detection device having a gain that attenuates with an increase in frequency in at least a part of a frequency range in which a gain of the signal with respect to the detected current increases, and becomes unattenuated with a further increase in frequency.