DE10108640A1 - Contact-free current measurement device has an array of two similar magnetic field sensors for measuring equal currents flowing in opposite directions in parallel conductors, such that measurements are insensitive to position - Google Patents

Contact-free current measurement device has an array of two similar magnetic field sensors for measuring equal currents flowing in opposite directions in parallel conductors, such that measurements are insensitive to position

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Publication number
DE10108640A1
DE10108640A1 DE2001108640 DE10108640A DE10108640A1 DE 10108640 A1 DE10108640 A1 DE 10108640A1 DE 2001108640 DE2001108640 DE 2001108640 DE 10108640 A DE10108640 A DE 10108640A DE 10108640 A1 DE10108640 A1 DE 10108640A1
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Germany
Prior art keywords
conductor
sensors
current
sensor
conductor sections
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DE2001108640
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German (de)
Inventor
Udo Ausserlechner
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Infineon Technologies AG
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Infineon Technologies AG
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Priority to DE2001108640 priority Critical patent/DE10108640A1/en
Publication of DE10108640A1 publication Critical patent/DE10108640A1/en
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00 and G01R33/00 - G01R35/00
    • G01R15/14Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/202Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00 and G01R33/00 - G01R35/00
    • G01R15/14Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/207Constructional details independent of the type of device used

Abstract

Sensor arrangement comprises two parallel current sections (L1, L2) with current (I1, I1') flowing in the opposite directions within them and two sensors (S1, S2) in a common chip (IC) arranged parallel to the conductor plane. The measurement values from the sensors are combined and evaluated by an analysis circuit. The sensors measure the magnetic field component in a plane perpendicular to the current sections (xy). Optimally the sensors are Hall effect sensors of similar properties in an ASIC chip. The conduction sections are typically flat conductors on a PCB.

Description

The present invention relates to a sensor arrangement for contactless current measurement.

The measurement of a current by means of the magnetic field which is caused by a current-carrying conductor well known. The current to be measured is tactless with a magnetic field sensor, for example one Hall element or a field plate. With this metho de it is not necessary to close the circuit for measurement to open. This eliminates contacting problems. Since the meas circuit is electrically isolated from the current to be measured measurements at high voltages can also be carried out safely become. Furthermore, the current measurement with the one described Method practically lossless and non-reactive.

The described advantages of contactless current measurement however, there are serious disadvantages in practice. This is particularly the case with small and medium currents magnetic field surrounding the current-carrying conductor small in size. A current of 10 A through a circular Ladder, for example, causes a distance of 2 mm from the ladder axis a field of 1 mT. Hence the requirement to place a magnetic field sensor as close as possible to the conductor is.

In practical applications, measurement errors can be described with the benen measuring principle arise, for example, that the Relative position of the sensor to the conductor, more precisely to the conductor axis, is subject to fluctuations, for example due to of manufacturing tolerances. The magnetic field through a current Floating ladder is proportional to the reciprocal of the distance of the sensor to the conductor axis. So a position deviation in radial direction from the conductor of 0.1 mm in the example above  already at a relative measurement error of 4.8%. Next manufacturing-related errors, which are still relatively can be calibrated out, further measurement errors can occur thermal effects, evaporation of plasticizers in plasto or swelling due to absorption of water vapor to step. Another source of error for the current measurement Method are background fields, for example the earth field, remanent fields of nearby iron parts as well as transient Interference caused by ignition coils, brush fire etc., wel all contribute to falsifying a measurement result can. It is known to measure due to background fields errors, for example, through mu-metal screens or through dif differential measurements using an S-shaped conductor loop to avoid. Furthermore, to avoid positi tolerance errors with transformer sheets or magnetic ceramics concentrated magnetic flux and an air gap in which the field is almost homogeneous. Practical reali However, fixtures of the measuring devices described have the disadvantage that they are of temperature characteristics of the magnet depending on the material and with a high weight and high manufacture service costs are connected.

In the document "Non-plate-like Hall magnetic sensors and their applications "by R. S. Popovic, Sensors and Actuators 85 (2000) 9-17, a vertical Hall sensor is specified, which can detect a magnetic field that is parallel to the chip Hall sensor surface.

Derivation for analytical field calculation of magnetic fields Rectangular conductors, for example, the Do document "Electrodynamics of Electrical Machines", Milos Stafl, Czechoslovak Academy of Sciences, 1967, pages 65 ff men.

The object of the present invention is to arrange a sensor to specify the contactless measurement of a current  insensitive to manufacturing problems with simple construction satchel is.

According to the invention, the object is achieved with a sensor arrangement for contactless current measurement

  • - A first conductor section for guiding one to be measured current
  • - A second conductor section, the same Erstrec direction like the first conductor section and from this is arranged spaced, for guiding the measured Current in opposite directions with respect to the first conductor section Current direction,
  • - A first sensor for detecting one of those to be measured Current-induced magnetic field component parallel to that level spanned by the conductor sections, the one he provides the most measured value,
  • - A second sensor for detecting one of those to be measured Current-induced magnetic field component, parallel to that level spanned by the conductor sections, the one provides second measured value, and
  • - An evaluation circuit that is used to transmit the first and second measured value is coupled to the first and second sensor, and the output side by linking the first and provides a second measurement value formed measurement signal.

The first and second conductor sections can ne parallel be arranged side by side. As far as always within the scope possible conductor losses possible, the amount of current in first conductor section equal to the amount of current in the second Lei section.

The sensors are preferred for achieving a good pairing executed in the same way and in particular have the same emp sensitivity to.

If the sensors are designed as Hall sensors, this is done the provision of the measurement signal by means of the evaluation circuit  through difference formation when the sensors, for example have the same orientation and in the same direction from one Excitation current or primary current are flowed through. With ver different current direction or different orientation or Orientation of the sensors is an adaptation of the Evaluation circuit, especially the linking of the first and the second measured value.

The described, differential measuring system is largely independent of the exact lateral position of the Sensors regarding the conductor sections, and practically independent dependent on homogeneous magnetic background fields.

The sensors are preferably together in one plane arranged, which is perpendicular to the preferred direction of the Lei sub-sections stands.

The measurement signal obtained in the evaluation circuit is a highly accurate image of the current and the direction of the Current through both conductor sections and can thus touch smooth current measurement with all of the above Advantages such as freedom from losses, freedom from retroactive effects, galva African separation, safe measurement of high voltages as well No opening of the circuit used for measurement be.

In particular, the sensor arrangement described is well integrated gratable because the conductor sections, for example, conductor tracks can be a printed circuit on which a chip is placed is soldered, which includes the two sensors.

In addition to the described two sensors can also other sensors, for example to further improve the Un suppression of homogeneous background fields can be provided.

In a preferred embodiment of the present invention The sensors are in a common application specific  Integrated circuit, ASIC, integrated. The chip The ASIC is preferably parallel to that of arranged the conductor sections spanned level. The Sensors are preferably on a common main surface surface of the chip.

In a further, preferred embodiment of the present According to the invention, the sensors are Hall elements. Hall elements in addition to very good integrability, have a high measurement accuracy on.

In a further, preferred embodiment of the present the invention are the sensors as vertical Hall elements designed to detect magnetic field components in parallel to a main area of the ASIC. The sensors measure accordingly each a component of the magnetic field, which on the one hand in the chip level, that is parallel to the main surface of the Chips and parallel to the conductor branches and the other nor times or perpendicular to the direction of current flow is.

Vertical Hall probes have a particularly good Lang time stability, so that, if any adjustment or a calibration is required, a one-time calibration sufficient after production. Hall sensors also feature low sensitivity to homogeneous background fields.

In a further, preferred embodiment of the present the invention, the conductor sections each have a right corner cross section. The rectangular cross section of the On the one hand, conductor sections offer good field homogeneity and on the other hand, such a sensor arrangement has one low sensitivity to production-related or positional tolerances between the Sensors and the conductor sections. In addition, can be right Then, for example, angular conductor cross sections without problems  be provided if the conductor sections conductor tracks or Copper tracks or aluminum tracks of printed circuits in a wiring level, for example on a printed circuit board tine, PCB (Printed Circuit Board).

In a further, preferred embodiment of the present the invention is that spanned by the conductor sections Plane parallel to a major surface of the ASIC and is a plane of symmetry formed by the conductor sections at the same time a plane of symmetry with regard to the arrangement of the sen sensors in the ASIC. Ensure a high symmetry of the arrangement firstly the possibility of exact measurements and secondly whose good integrability of the arrangements. Should the Plane of symmetry of the sensors in a direction perpendicular to Current direction, for example parallel to the conductor section and to a main area of the ASIC by a certain amount deviate, the present sensor arrangement le diglich, as already described, a relatively small sensitivity to such positional tolerances.

In a further, preferred embodiment of the present the invention provides a U-shaped conductor loop, whose legs each include one of the two conductor sections. The conductor loop, especially the part that the connecting the two conductor sections is in provide sufficient distance to the sensor ASIC to allow the mag net field not inadmissible in the area of the sensors rule. Such a conductor loop still has the front partly that it is easy to manufacture and that the ladder cuts are almost at the same potential. This can for example the distance between the conductor sections be reduced. A marginal drop in voltage between the two conductor sections is usually inevitable but shows no relevant negative effects on be written circuit arrangement.  

In a further, preferred embodiment of the present According to the invention, the conductor sections of conductor tracks are based on comprises a circuit board on which the ASIC is attached.

The conductor sections L1, L2, or the U-shaped Conductor loops can also advantageously be used as metal tracks right on the IC surface or as a specially designed Lead frame of the ASIC.

The ASIC can do this directly, for example with its Supply pins to be soldered to the conductor sections. The Conductor sections can, for example, be part of an accessory tion pair for the voltage supply of another component be a group. In this case, the sensor arrangement can be the power requirement of the other component group is particularly advantageous pe can be determined. There is an additional advantage through that required to operate the sensor assembly Supply voltage directly from the conductor tracks, which which include conductor sections can be obtained. itself can be understood with such a design of the sensor arrangement voltage due to the potential difference required here between no conductor loop in U-shape, such as described in the previous section.

The first conductor section can be part of a conductor track, which carries the supply voltage of a circuit block, and the second conductor section can have a conductor track around it be summarized, which is the ground potential for supplying a Circuit block leads.

In a further, preferred embodiment of the present the invention is the lateral extent of the cross section through one of the two conductor sections in the one of these spanned plane large compared to the sum of the distance the conductor sections from each other and the distance between the Sensors and the conductor sections. The sum of the distance the conductor sections from each other and the distance between the  Sensors and the conductor sections can be created through product formation this intermediate result with a safety factor be increased. Compared to this increased number the lateral extent of the cross section through the two Large conductor sections in the plane spanned by these his. It should be noted, however, that the lateral expansion the cross section through the two conductor sections in the upper limit of the level spanned by these is that the field component to be measured increases with late ral expansion decreases and thus the overall sensitivity and thus the resolution of the current measurement drops. The distance the conductor sections from each other, however, is down due to the dielectric strength between the two conductors cut limited. It can be an advantage to stay in a between the conductor sections formed to increase the dielectric strength to incorporate an insulating material gene, which has precisely defined penetration properties. The ambient air is bad as such an insulating material suitable, because their dielectric strength among other things from Fluctuations in the moisture content of the air depends. Insulating materials to be introduced can be, for example, an iso lierlack or a potting compound.

The distance between the sensors and the conductor sections should be chosen as low as possible. This will create a lowest possible sensitivity to incorrect positioning towards the plane of symmetry of the sensors with respect to the symmetry level of the conductor sections to each other.

In a further, preferred embodiment of the present According to the invention, the evaluation circuit comprises a difference bildner, with a plus input that with the first sensor is coupled, and with a minus input, which with the two th sensor is coupled, and with an output that is connected to the Input of a threshold detector is connected and the measurement signal compared with a predefinable threshold value. Depending on Orientation of the sensors and depending on the excitation current,  if it is Hall sensors, can instead the formation of the difference also requires a summation his.

An amplifier stage can be connected downstream of the difference former his. If an upper threshold is exceeded or if Falling below a lower threshold can result from the off value circuit for example who generates an error signal which, for example, detecting a short circuit ses in a circuit. In this case, for example, a switch controlled by the evaluation circuit be interrupted which interrupts the power supply. All be wrote and needed for such an evaluation circuit Such circuit parts can be provided externally or all be integrated in an ASIC.

Further details of the invention are the subject of Un subclaims.

The invention is illustrated below in several embodiments play with reference to the figures. Show it:

Fig. 1 section a first exemplary embodiment of he inventive sensor arrangement in a cross,

Fig. 2, the field component of the magnetic induction according to Fig. 1 in the x-direction on the chip surface,

Fig. 3, the difference in magnetic field components on the Sen 1 sensors of the arrangement according to FIG. In the x-direction in response to a positional tolerance of the measuring device as well as for different parameter values of the distances of the sensors from each other,

Fig. 4 shows the relative measurement error of the arrangement in a position dependent speed of tolerance for different parame terwerte the distance of the sensors from each other,

Fig. 5 shows an exemplary development of the measuring arrangement shown in FIG. 1 with a conductor loop in a U shape,

Fig. 6 shows another exemplary development of the measuring arrangement of FIG. 1 for measuring the supply current of a switching block and

Fig. 7 shows an exemplary evaluation circuit of the sensor measured values with threshold detection.

The chip surface or main surface of the chip is as follows designates that surface of the integrated circuit the structure of the circuit, for example by means of photo lithography, etching technology, implantation steps, diffusions steps and oxidation steps is applied. Thereby be are the active elements, such as the Hall probes, at a shallow depth of a few micrometers under the solid surface of the integrated circuit. This shallow depth finds out in the further consideration For the sake of simpler and clearer presentation no consideration.

Fig. 1 shows a sensor arrangement for contactless current measurement in a cross section through a rectangular first conductor section L1 and a rectangular second conductor section L2, which run in parallel and in opposite directions through which the same amount of current flows. The current in the first conductor section L1 is denoted by I1, the current in the second conductor section L2 by I1 '. The conductor sections L1, L2 are arranged in parallel and spaced apart and run side by side in a plane. In the Cartesian coordinate system shown in FIG. 1, this plane is the xz plane. An integrated circuit IC, which is designed as an Application Specific Integrated Circuit, ASIC, is arranged at a distance h parallel to this, spanned by the conductor sections L1, L2 and along the upper surfaces of the plane. This has a first sensor S1 on a main side Lic facing the conductor sections L1, L2 and a second sensor S2 arranged on the ASIC symmetrically to the first.

In Fig. 1, the sensor arrangement is not shown in ideal symmetrical ratios, but with an exaggerated net position tolerance eps, which may be manufacturing-related and which the distance of the axis of symmetry of the integrated circuit IC with respect to the sensors S1, S2 from the axis of symmetry of the conductor sections L1 , L2 denotes net, which in the cross section shown is just the y-axis of a drawn coordinate system. The distance of the sensor in the middle of the sensors S1, S2 from the axis of symmetry of the integrated circuit IC is denoted in each case by ds / 2. The conductor sections L1, L2 are each at a distance d from their plane of symmetry, which is the yz plane in the present illustration. It follows that the Leiterab sections L1, L2 have a total distance of 2 d from each other. The dimension of the conductor sections L1, L2, which are formed symmetrically to one another, in the x-direction is each designated 2 a, while the extension of the conductor sections in the y-direction, that is to say the thickness of the conductor sections L1, L2, is designated 2 b , Finally, the level in which the main area of the integrated circuit, that is to say the active front side of the IC with the integrated sensors S1, S2, is designated by Lic.

When dimensioning the geometry of the described sensor arrangement according to FIG. 1, it should be noted that the integrated circuit IC is located on those edges on which the two conductor sections have the smallest distance from one another. There the ASIC integrated circuit IC is located directly above this edge. The integrated circuit IC has at least two sensors S1, S2, each of which can detect a magnetic field component which is parallel to the xz plane, that is to say the plane of the main surface of the integrated circuit, and at the same time perpendicular to the direction of the current flow I1, I1 ' is arranged. With evaluation electronics, which can be arranged in the integrated circuit IC or can be provided externally, the measurement values of the sensors can be recorded and linked to form a measurement signal. A measurement signal obtained in this way is a highly accurate image of the current intensity I1, I1 'in the conductor sections L1, L2 and can thus be used for contactless current measurement.

With regard to the positional tolerance eps shown, the measuring arrangement according to FIG. 1 shows only a low sensitivity.

The x component of the magnetic induction B, which of the sensors designed as vertical Hall sensors can be detected and is caused by the currents I1, I1 'is shown in fol designated with Bx.

In the dimensioning of the geometry of the measuring arrangement according to FIG. 1, the information explained below can be advantageous: A large conductor width 2 a leads to a further improved insensitivity of the measuring arrangement to position tolerances eps. The field profile of the x component of the magnetic field Bx at the position of interest y = b + h leads to a largely constant magnetic field component Bx over the conductor sections L1, L2, that is to say for x values from - (d + a) to - d and from + d to + (d + a) and for y = b + h. Now one of the two sensors S1 is in point

(x, y, z) = (d + a, b + h, z)

and the other sensor S2 in point

(x, y, z) = (-d - a, b + h, z)

placed, the difference between the two sensor signals is white Test independent of small positional tolerances eps of the ge entire IC in the reference system of the conductor sections L1, L2, ins especially if the two sensors S1, S2 as in the Embodiment shown in a common component IC are integrated and therefore a precisely defined distance ds of each other, which then tolerances in size order of less than 1 µm.

The sensors S1, S2 should each be arranged so that the first derivative of the B-field component in the x-direction Bx just disappears. In practice, the exact position can usually be obtained by numerical field calculation. A particularly advantageous position of the first sensor S1 at location x1 and the second sensor S2 at location x2 results from the following conditions:

and for reasons of symmetry

x2 = - x1.

In a first approximation, however, the following applies to an advantageous position of the first sensor S1:

x1 ≅ d + a.

Particularly advantageous for the described insensitivity to position tolerances are conductor tracks with a width 2 a, for which the following applies:

2 a » 2 d + h.

The conductor width 2 a is limited to large values by the fact that the field Bx in the xz plane or a plane parallel to it with y = b + h decreases with increasing parameter a and thus the sensitivity and consequently also the resolution of the entire current measuring arrangement drops.

When dimensioning the thickness 2 b of the conductor sections L1, L2, it should be noted that the distance between the sensors and the current-carrying conductor sections L1, L2 should be as small as possible in the interest of a high measurement resolution. Accordingly, the conductor thickness 2 b should be relatively small and the distance h of the sensors S1, S2 from the conductor sections L1, L2 should also be small. The sensors S1, S2 themselves can, for example, be diffused into the chip surface Lic or its active front side to a maximum depth of a few μm. Consequently, the measuring arrangement described is particularly well suited for mounting directly on a printed circuit board PCB, printed circuit board, where the conductor sections L1, L2 are designed as conductor tracks on the top of the board, which in this case has a thickness 2 b of, for example, 35 µm. Of course, the conductor tracks L1, L2 are arranged on the top of the circuit board on which the integrated circuit IC is to be fastened.

For small values, the conductor thickness 2 b is of course determined by the maximum permissible current density in the conductor material. This in turn depends on the design of the cooling surfaces, the reliability and the service life of the conductors and the composite materials that may surround them, as well as on a maximum permissible voltage drop at the conductors L1, L2.

For the dimensioning of the distance h between the main surface Lic of the integrated circuit IC and the conductor sections L1, L2, the distance h, as already stated, should in principle be as small as possible, but towards small values due to the dielectric strength between the conductors and the chip L1, L2, IC is given, where applicable the legally required insulation classes as well as safety-related aspects must be observed. It is particularly to be avoided that, if the value of the position h is too small, an electrical flashover from one of the conductor sections L1, L2 takes place on the integrated circuit IC. The minimum required distance h can be found with the formula

U max = E max h min s,

determine; with the product U max the same voltage strength in volts, E max the dielectric strength of the insulator between the IC and the conductor track, depending on the type of insulator selected, such as air, insulating varnish or sealing compound and a safety factor s.

When dimensioning the conductor thickness 2 b, sensitivity aspects of the sensors can also play a role: if a larger current range can be detected with a given sensor S1, S2, this can be achieved by increasing the conductor thickness 2 b. In this case, advantageously the width 2 a of the conductor portions L1, L2 are ßert magnification, which the magnetic field in the region of the sensors S1, S2 must be weighed, however, against the poorer then homogeneity.

Be within the range of the sensors S1, S2, the homogeneity of the Ma gnetfeldes be further improved, the conductor cross can cut not be chosen exactly rectangular, but it Kgs nen in the region of half the width 2a of the conductor sections L1, L2 material tapers be provided. Such a manufac turing measure, however, is to be weighed against the required additional manufacturing costs, depending on the application.

The distance 2 d of the two conductor sections L1, L2 from one another should advantageously be as small as possible. As with the stand h, the lower limit is the voltage strength between the potential at the conductor section L1 and the potential at the conductor section L2. At a small distance 2 d, a curve Bx (x, b + h, z) results as a function of the x coordinate, which has a very large slope in terms of magnitude in the vicinity of the origin of the coordinate system shown. This makes it possible to keep the distance ds between the two sensors S1, S2 small, which in turn enables integration of both sensors S1, S2 on a common chip IC. Of course, if necessary, an insulator other than air, for example an insulating varnish, can also be introduced in the space between the conductor sections L1, L2.

In the dimensioning of the sensor arrangement according to FIG. 1, it should also be noted that both sensors S1, S2 have exactly the same sensor sensitivities, because if the sensitivity of the sensors S1, S2 were not the same, the difference between the two measured field components Bx in the two sensors S1, S2 no longer completely suppresses a homogeneous background field. Due to the good long-term stability when using vertical Hall probes, it is possible to calibrate or calibrate them at the block level in a final test after production, so that they have minimal sensitivity to homogeneous background fields.

The measuring arrangement according to FIG. 1 advantageously has good symmetry properties. Small deviations from ideal symmetry properties, as they are usually unavoidable in mass production, cannot affect the quality of the entire measurement signal in the present arrangement, however, or can, in the case of particularly high demands on accuracy, by trimming the sensitivity of the sensors S1, S2 be calibrated out.

In addition to the advantages described, the arrangement according to FIG. 1 has all the advantages of a contactless current measurement, such as no contacting problems, galvanic separation of the sensitive measuring circuit from the circuit to be measured, the possibility of measuring at a high DC voltage potential, no requirement for series resistance in the primary circuit, and no loss of power loss and freedom of feedback of the measurement. Elaborate and expensive mu-metal shielding from external fields or background fields can be omitted. The complex manufacturing of a conductor loop in the form of an S is not necessary. Finally, the circuit as a whole has low manufacturing costs, inexpensive producibility, suitability for mass production processes and applicability directly to conductor tracks on a circuit board.

Fig. 2 shows the magnetic field component Bx of the magnetic induction in the x direction in the unit mT (milli-Tesla) in Ab dependence of x in the unit (meter) m in height y = b + h, that is on the chip surface.

The following assumptions are made for the geometry data of the measuring arrangement: 2 a = 4 mm, 2 b = 40 µm, 2 d = 0.1 mm, h = 0.2 mm, I1 = -I1 '= 10 A. The conductor section L1 extends in the x direction from x = -0.0045 to x = -0.0005, the conductor section L2 from x = 0.0005 to x = 0.0045. The conductor thickness 2 b = 40 µm is a typical thickness of a copper layer, as is usually seen as a conductor track on PCBs, printed circuit boards. The conductor sections L1, L2 run parallel in the z direction and the adjacent edges of the conductor sections are spaced apart from one another by 2 d = 0.1 mm. The active surface of the integrated circuit IC is 0.2 mm above the surface of the conductor sections. Both conductor sections L1, L2 each carry a current of 10 A, but in opposite current directions. This results in a magnetic flux density of approximately 1.5 mT at each of the two sensors S1, S2, that is to say a difference field of 3 mT. The profile of the arrangement has two flat plateaus, egg by x = -0.002 and another by x = 0.002, such that relatively small positional deviations eps in the x direction do not significantly falsify the measurement result.

It can be seen that the induction Bx directly above the conductors L1, L2 is predominantly constant with respect to x, and is negative via L2, but positive via L1. If the integrated circuit IC contains two probes S1, S2, which react to the x component of the induction, and if the difference between the two probe signals is determined by signal processing in the IC, curves as shown in FIG. 3 result.

Fig. 3 shows a family of curves of the differential magnetic field, respectively as the x-field component at the sensor positions S1, S2 in milli Tesla in response to a positional tolerance eps in x-direction. The distance ds of the two sensors S1, S2 from one another is selected as the coulter parameter. The curves are drawn for ds = 1 mm, ds = 2 mm, ds = 4 mm and ds = 6 mm. A current of 10 A was assumed. Furthermore, the conductor width 2 a to 4 mm, the conductor thickness 2 b to 40 µm and the distance of the conductor sections from each other to 2 d = 0.1 mm were assumed, while the distance of the sensors from the conductor sections was fixed at 0.2 mm , The geometry data of the arrangement are therefore identical to those of Fig. 2. It can be clearly seen that the measurement result is least sensitive to positional deviations eps in the x direction if and only if the sensors S1, S2 have approximately the same distance from one another like the centers of the two conductor sections L1, L2, in this case ds = 4.1 mm. All curves whose distance between the sensors is smaller than the distance between the conductors, i.e. the curves for ds = 1 to ds = 4 mm, have common zero points, while those curves in which the sensor distance ds is greater than the distance between the conductors in the middle L1, L2 from each other, each have individual zero points. Consequently, the curve plateau, which results in the vicinity of origin, can be formed very flat by suitable selection of the sensor distance of the ds, so that there is a good sensitivity of the measurement results to position tolerances eps in the x direction.

From Fig. 3 it also follows that at the location of the common zero point for small sensor distances ds a third and fourth sensor can be used in the integrated circuit IC, who can be positioned exactly at the location of the common zero points and a measurement of the inhomogeneous portion of a background field allows. The difference signal of the first and second sensors S1, S2 can thus be easily cleaned with the downstream evaluation electronics for the measured value of this background field.

Fig. 4 shows the relative measurement error of the measurement signal in front of lying sensor arrangement according to FIG. 1 as a function of a position deviation eps. The coulter parameter is again given the distance ds of the sensors S1, S2 from one another. The geometry parameters 2 a, 2 b, 2 d, h, and the current intensities I, I 'are the same as in FIGS. 2 and 3. It is clearly recognizable that the measurement result is most insensitive to positional deviations eps when the distance the sensors ds from each other approximately corresponds to the distance between the conductor centers of the conductor sections L1, L2. The best insensitivity results according to the present diagram for ds = 4.1 mm. If smaller sensor distances are to be used to save chip area or to produce smaller chips or ASICs, then for example for a sensor distance ds of 2.5 mm for the specified conductor geometry there is a relative measurement error of only 0.5% with a position deviation of 0.25 mm.

Fig. 5 shows a U-shaped conductor loop, the legs of which comprise the conductor sections L1, L2. The integrated circuit IC is to be arranged at a sufficient distance from the actual loop so as not to falsify the magnetic field of the conductor loop at the location of the sensors S1, S2. Advantageously, in accordance with the embodiment of Fig. 5, which has a, as seen from eps of the position tolerance, as has in Fig. 1-described NEN cross-section, the electric potential of Lei terabschnitts L1 substantially equal to the electric potential of the conductor portion L2, whereby a particularly From 2 d stood between the conductor sections L1, L2 is made possible.

FIG. 6 shows a further exemplary embodiment of the invention, which is a development of the arrangement according to FIG. 1. An integrated circuit IC with two sensors S1, S2, as described in FIG. 1, is arranged above two conductor sections L1, L2, which, however, in the embodiment according to FIG. 6 for guiding an electrical supply voltage VCC, GND to a switching block SB are suitable. The first conductor section L1 carries a supply potential VCC and the second conductor section L2 carries a reference potential GND. The circuit block SB is dissolved to its power supply with a connection pin PIN0, PIN1 on each of a conductor section designed as a conductor section L1, L2. The integrated circuit IC itself is connected to its own power supply via a connection pin PIN2, PIN3, each with a conductor section designed as a conductor section L1, L2, the current flow of which can be measured with the integrated circuit IC, by soldering.

Are the two conductor sections L1, L2 identical to the Supply lines of a circuit block SB, so is the Potential difference between the two conductor sections L1, L2 identical to the supply voltage of the switching block kes and it is even possible to use the integrated circuit IC to operate with the same supply voltage by the Supply pins PIN2, PIN3 directly on the conductor tracks L1, L2 are soldered on. This creates a particularly space saving and efficient measuring arrangement for the detection of the current consumption of a switch block SB. For example with a  Evaluation circuit that a threshold detector for short final version includes, can also easily Protective circuit for the SB circuit block can be implemented.

Finally, FIG. 7 shows an evaluation circuit which links the measured values M1, M2 which can be derived on the sensors S1, S2 on the output side to form a difference. A summing node SK is provided here, to which the first measured value M1 is supplied unchanged and the second measured value M2 is inverted. The output of the summing node SK is connected to the input of a window comparator FK, which compares the measurement signal difference provided at the output of the summing node with an upper and a lower threshold value limit MAX, MIN. For example, when a short circuit is detected, a corresponding error signal can be generated using the window comparator FK.

In a generalized form of the Aus described so far it would also be possible to use any line ar combination of two currents I1, I2, one being most current I1 flows through conductor L1, a second current I2 flows through conductor L2 and the coefficients of the line arkombination by the sensitivities E1, E2 of the two Sensors S1, S2 are formed, according to E1 × I1 + E2 × I2. In In this case, the currents I1, I2 may not be available causal relationship with each other. Potentia too le of the conductor sections L1, L2 are through the sensor itself not specified. An advantage of such an arrangement is that both currents I1, I2 are offset against each other can, regardless of a possibly high and poor de defined potential difference of the live conductor le. A complete compensation of homogeneous background fields however, this is only achieved for E1 = E2.

All of the described exemplary embodiments for current measurement are regardless of whether it is DC or AC electricity that is to be recorded. Even mixed versions,  for example direct current in conductor L1 and alternating current in conductor L2 is possible.

To further improve the sensitivity of the measuring arrangement highly permeable sheets, for example a Metal sheet, below the conductor sections, that is the side of the conductor sections opposite the chip, be arranged. Can further improve EMC (Electromagnetic Compatibility) strength the arrangement with the conductor sections L1, L2 and the integrated Circuit IC with grounded, conductive foils, for example wise copper foil, to be wrapped.

Claims (10)

1. Sensor arrangement for contactless current measurement, comprising
  • a first conductor section (L1) for carrying a current (I1) to be measured,
  • - A second conductor section (L2), which is arranged in the same direction of extension (z) as the first conductor section (L1) and spaced therefrom, for guiding the current to be measured (I1 ') in the opposite direction to the first conductor section (L1) .
  • - A first sensor (S1) for detecting a magnetic field component (Bx) caused by the current to be measured (I1, I1 ') parallel to the plane (x2) spanned by the conductor sections (L1, L2), which has a first measured value (M1 ) provides
  • - A second sensor (S2) for detecting a magnetic field component (Bx) caused by the current to be measured (I1, I1 ') parallel to the plane (x2) spanned by the conductor sections (L1, L2), which has a second measured value (M2 ) provides and
  • - An evaluation circuit (SK, FK), which is coupled to the first and second sensor (S1, S2) for transmitting the first and second measured value (M1, M2), and which is connected on the output side by linking the first and second measured value (M1, M2 ) Provides measured signal.
2. Sensor arrangement according to claim 1, characterized in that the sensors (S1, S2) in a common integrated Circuit (IC), in particular an Application Specific Inte grated circuit, are integrated.
3. Sensor arrangement according to claim 1 or 2, characterized in that the sensors (S1, S2) are Hall elements.
4. Sensor arrangement according to claim 2 and 3,  characterized in that the sensors (S1, S2) are designed as vertical Hall elements are parallel to the detection of magnetic field components (Bx) a main surface of the integrated circuit (IC).
5. Sensor arrangement according to one of claims 1 to 4, characterized in that the conductor sections (L1, L2) each have a rectangular shape Have cross-section.
6. Sensor arrangement according to one of claims 2 to 5, characterized in that the plane spanned by the conductor sections (L1, L2) parallel to a main surface (Lic) of the integrated scarf device (IC) is arranged and that one of the conductor section th (L1, L2) formed plane of symmetry (yz) also a sym level of measurement with regard to the arrangement of the sensors (S1, S2) in the integrated circuit (IC) is.
7. Sensor arrangement according to one of claims 1 to 6, characterized in that a U-shaped conductor loop is provided, the legs each include one of the two conductor sections (L1, L2).
8. Sensor arrangement according to one of claims 2 to 6, characterized in that the conductor sections (L1, L2) of conductor tracks on a pla tine are included on which the integrated circuit (IC) be is consolidated.
9. Sensor arrangement according to one of claims 1 to 8, characterized in that the lateral extent of the cross section ( 2 a) of the two Lei terabschnitte (L1, L2) in the leveled by these ne (xz) is large compared to the sum of the Distance ( 2 d) between the conductor sections (L1, L2) and the distance (h) between the sensors (S1, S2) and the conductor sections (L1, L2).
10. Sensor arrangement according to one of claims 1 to 9, characterized in that the evaluation circuit (SK, FK) a difference generator (SK) includes, with a plus entrance, which with the first Sen sor (S1) is coupled, and with a minus input that with the second sensor (S2) is coupled, and with an output, connected to the input of a threshold detector (FK) and the measurement signal with a predefinable threshold value (MIN, MAX) compares.
DE2001108640 2001-02-22 2001-02-22 Contact-free current measurement device has an array of two similar magnetic field sensors for measuring equal currents flowing in opposite directions in parallel conductors, such that measurements are insensitive to position Withdrawn DE10108640A1 (en)

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CN108333410A (en) * 2017-01-04 2018-07-27 大众汽车有限公司 Dome module and energy supply system for energy storage
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DE102004021862B4 (en) * 2004-05-04 2014-08-07 Infineon Technologies Ag current Senor
DE102004021862A1 (en) * 2004-05-04 2005-12-01 Infineon Technologies Ag Current sensor has two lead frames each having a magnetic field sensor chip that are attached to the frame opposite one another
DE102006028520B4 (en) * 2005-06-21 2009-04-30 Denso Corp., Kariya-shi Current sensor with a Hall element
JP2007121283A (en) * 2005-10-08 2007-05-17 Sentron Ag Assembly group for current measurement
EP1772737A2 (en) * 2005-10-08 2007-04-11 Sentron Ag Assembly group for the current measurement
EP1772737A3 (en) * 2005-10-08 2008-02-20 Melexis Technologies SA Assembly group for the current measurement
US9859489B2 (en) 2006-01-20 2018-01-02 Allegro Microsystems, Llc Integrated circuit having first and second magnetic field sensing elements
US9082957B2 (en) 2006-01-20 2015-07-14 Allegro Microsystems, Llc Arrangements for an integrated sensor
US8629520B2 (en) 2006-01-20 2014-01-14 Allegro Microsystems, Llc Arrangements for an integrated sensor
US10069063B2 (en) 2006-01-20 2018-09-04 Allegro Microsystems, Llc Integrated circuit having first and second magnetic field sensing elements
US8952471B2 (en) 2006-01-20 2015-02-10 Allegro Microsystems, Llc Arrangements for an integrated sensor
WO2007085711A3 (en) * 2006-01-24 2007-09-20 Schneider Electric Ind Sas Device for measuring dc current having large measurement swing, electronic trip comprising such a measurement device and cut-off device having such a trip
CN101384910B (en) * 2006-01-24 2011-11-09 施耐德电器工业公司 Device for measuring DC current having large measurement swing, electronic trip comprising such a measurement device and cut-off device having such a trip
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FR2896591A1 (en) * 2006-01-24 2007-07-27 Schneider Electric Ind Sas Direct current measuring device for voltage trigger`s electronic converter card, has processing unit with selection unit providing output signal, which depends on measured signals of sensors, for weak and strong electric currents
FR2919730A1 (en) * 2007-08-02 2009-02-06 Abb France Current sensor for measuring current circulating in at least one driver
AT506682B1 (en) * 2008-04-17 2014-05-15 Adaptive Regelsysteme Ges M B H Current measuring device and method for the galvanically separated measurement of flows
US8779757B2 (en) 2010-06-07 2014-07-15 Infineon Technologies Ag Current sensor
US9366700B2 (en) 2010-06-07 2016-06-14 Infineon Technologies Ag Current sensor
DE102014100668B4 (en) * 2014-01-21 2017-12-14 Comexio Gmbh Current measurement device
DE102014100668A1 (en) * 2014-01-21 2015-07-23 Comexio Gmbh Current measurement device
WO2015124577A1 (en) * 2014-02-21 2015-08-27 Jungheinrich Aktiengesellschaft Industrial truck having a monitoring device
WO2016139028A1 (en) * 2015-03-03 2016-09-09 Magna powertrain gmbh & co kg Electrical assembly for measuring a current intensity of a direct-current circuit by means of the anisotropic magnetoresistive effect
CN107407697A (en) * 2015-03-03 2017-11-28 麦格纳动力系有限两合公司 Utilize the electric component of anisotropic magneto-resistive effect measurement DC circuit current strength
CN108333410A (en) * 2017-01-04 2018-07-27 大众汽车有限公司 Dome module and energy supply system for energy storage
EP3715892A1 (en) * 2019-03-28 2020-09-30 ABLIC Inc. Semiconductor device

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