CN104040362A - Current sensor - Google Patents
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- CN104040362A CN104040362A CN201280066547.0A CN201280066547A CN104040362A CN 104040362 A CN104040362 A CN 104040362A CN 201280066547 A CN201280066547 A CN 201280066547A CN 104040362 A CN104040362 A CN 104040362A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations 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
- G01R15/205—Adaptations 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 magneto-resistance devices, e.g. field plates
Abstract
The purpose of the invention is to provide a current sensor, the offset and sensitivity of which can be precisely adjusted at a time. The current sensor comprises: a magnetoelectric conversion circuit (11) for converting a magnetic field to a voltage and outputting the voltage from the output end thereof; a buffer amplifier circuit (12) connected to the output end of the magnetoelectric conversion circuit; and an adjustment circuit (13) for adjusting the output of the buffer amplifier circuit. The adjustment circuit has a first adjustment portion (131) for outputting the adjusted voltage from the output end thereof, a second adjustment portion (133) capable of adjusting the gain of the buffer amplifier circuit, and a buffer circuit (132) provided between the output end of the first adjustment portion and the second adjustment portion. The output voltage of the first adjustment portion adjusts the output offset of the buffer amplifier circuit.
Description
Technical field
The present invention relates to can be to measure the current sensor of determined electric current non-contactly.
Background technology
The field of the direct motor drive technology in electric automobile, hybrid electric vehicle etc., owing to will disposing the large electric current of comparison, therefore seeks to measure non-contactly the current sensor of large electric current towards these purposes.And, as such current sensor, propose to detect with magnetic detecting element the current sensor of mode of the variation in the magnetic field producing because of determined electric current.
In using the current sensor of magnetic detecting element, the sensitivity of magnetic detecting element due to because of element different different, therefore, in order to obtain the corresponding desired sensor output with determined electric current, need gain (sensitivity) to adjust and biasing (side-play amount of the reference value of the sensor output while being 0A from determined electric current) is adjusted.For example, in patent documentation 1, propose a kind of current sensor, eliminate the variation of the drive current of the magnetic detecting element causing because of sensitivity adjustment, prevent the variation of bias voltage, simplify and adjust thus.
Look-ahead technique document
Patent documentation
Patent documentation 1:JP JP 2010-127636 communique
The summary of invention
The problem that invention will solve
Current sensor that patent documentation 1 is recorded is adjusted biasing on one side through determination sensor output on one side and is adjusted the step of resistance of use and determination sensor and export one side and regulate the step of the resistance that adjustment of sensitivity uses to adjust.That is,, in the adjustment of this current sensor, the measured value that need at least carry out the output of 2 cooperation sensors makes to adjust the step of the resistance variations of use.So, in the current sensor of recording at patent documentation 1, owing to can not disposablely adjusting adjusting the resistance value of use, therefore there is the such problem of taking time of adjusting.In addition, at this current sensor, due to one side determination sensor output one side adjusting resistance value, the such problem of resistance that can make resistance value gradually change of therefore having in addition use.
Summary of the invention
The present invention proposes in view of reference point, and object is, provides the disposable precision of energy to adjust well the current sensor of biasing and sensitivity.
For solving the means of problem
Current sensor of the present invention is characterised in that to possess: the magnetoelectricity translation circuit that magnetic field is transformed into voltage and exports from output terminal; The buffer amplifier circuit being connected with the output terminal of described magnetoelectricity translation circuit; With the Circuit tuning of adjusting the output of described buffer amplifier circuit, described Circuit tuning has: the 1st adjustment part of exporting adjusted voltage from output terminal; Can adjust the 2nd adjustment part of the magnification of described buffer amplifier circuit; And be located at the output terminal of described the 1st adjustment part and the buffer circuit between described the 2nd adjustment part, by the voltage of described the 1st adjustment part output, adjust the biasing of the output of described buffer amplifier circuit.
According to this formation, due to for adjust buffer amplifier circuit output biasing the 1st adjustment part and for adjusting between the 2nd adjustment part of magnification of buffer amplifier circuit, be provided with buffer circuit, the biasing set-up procedure of therefore being undertaken by the output adjustment of the 1st adjustment part can not be subject to the impact of the sensitivity adjustment step of being undertaken by the 2nd adjustment part.Thus, can disposable precision adjust well biasing and sensitivity.And, need to not be provided for adjusting at buffer amplifier circuit the special-purpose terminal of biasing yet.Therefore in addition, due to the constant balance that can not confuse in buffer amplifier circuit, can prevent the characteristic variation of the amplifying circuit of temperature characterisitic etc.
In current sensor of the present invention, preferred described buffer amplifier circuit is to possess the 1st input end being connected with described magnetoelectricity translation circuit, the 2nd input end being connected with described Circuit tuning and the operational amplifier of output terminal, described the 2nd adjustment part has the 3rd adjusting resistance and the 4th adjusting resistance being connected in series with described buffer circuit, and described buffer amplifier circuit and described the 4th adjusting resistance is in parallel.According to this, form, can form with simple circuit, allow magnetoelectricity translation circuit can not be subject to the impact of state of the output end of buffer amplifier circuit.In addition, the magnetoelectricity translation circuit impact of state of circuit side that is no longer adjusted.
In current sensor of the present invention, preferably described the 1st adjustment part has the 1st adjusting resistance and the 2nd adjusting resistance being connected in series between voltage source and ground connection, and described the 1st adjusting resistance and described the 2nd tie point of adjusting resistance and the input end of described buffer circuit are connected.
In current sensor of the present invention, preferred described magnetoelectricity translation circuit possesses: the bridge circuit with the magneto sensor that electrical specification changes corresponding to magnetic field; The magnetic field that input end is connected, measures corresponding to described bridge circuit with described bridge circuit and amplifying circuit that electric current is produced; The coil that one end is connected with the output terminal of described amplifying circuit; Be connected, produce and flow through the current-voltage conversion circuit of the corresponding voltage of electric current of described coil with the other end of described coil, the electric current that described amplifying circuit is controlled at described coil circulation produces and will be applied to the magnetic field of the magnetic field cancellation of described magneto sensor.According to this, form, although magnetoelectricity translation circuit becomes Low ESR output, owing to being provided with buffer amplifier circuit between magnetoelectricity translation circuit and Circuit tuning, therefore can prevent the amperometric determination deterioration in accuracy being caused by Circuit tuning.In addition, owing between magnetoelectricity translation circuit and Circuit tuning, buffer amplifier circuit being set, the electric current that therefore flows through coil can not be subject to the impact of circuit of the rear class of current-voltage conversion circuit.Thus, in the situation that the caused induced field of determined electric current is little, can to small coil electricity, carry out current-voltage conversion accurately.
In current sensor of the present invention, can described magneto sensor be also magneto-resistance effect element.
In current sensor of the present invention, preferred described buffer circuit is operational amplifier.
The method of adjustment of current sensor of the present invention is characterised in that to possess: magnetic field is transformed into voltage and from output terminal, exports the magnetoelectricity translation circuit of this voltage; For adjusting the Circuit tuning of voltage of the output terminal of described magnetoelectricity translation circuit; The buffer amplifier circuit being connected with output terminal with described magnetoelectricity translation circuit, described Circuit tuning possesses: the 1st adjustment part of exporting adjusted voltage from output terminal; And be located at the buffer circuit between the output terminal of described the 1st adjustment part and the input end of described the 2nd adjustment part, the method for adjustment of described current sensor possesses: the step to the magnitude of voltage of 2 different state estimating buffer amplifier circuit output terminals of the current value of the determined electric current of the current path circulation at determination object; Adjust the step of the output of described the 1st adjustment part and described the 2nd adjustment part with 2 magnitudes of voltage of the output terminal of buffer amplifier circuit based on described mensuration simultaneously.
The effect of invention
By the present invention, can provide the disposable precision of energy to adjust well the current sensor of biasing and sensitivity.
Accompanying drawing explanation
Fig. 1 means the schematic diagram of the formation summary of the current sensor that present embodiment is related.
Fig. 2 means the circuit diagram of the configuration example of the current sensor that present embodiment is related.
Fig. 3 means the circuit diagram of configuration example of the adjusting resistance of the current sensor that present embodiment is related.
Embodiment
Need separately to setover respectively in adjusting biasing and the current sensor of sensitivity set-up procedure and sensitivity adjustment step is can bring impact to the opposing party's set-up procedure because of a side set-up procedure.Present inventor is conceived to this point, by adjusting in the biasing adjustment part of use and the annexation of the sensitivity adjustment portion that sensitivity adjustment is used and make an effort in biasing, find out and can not make a side set-up procedure to the opposing party's set-up procedure, bring the method for impact, thereby complete the present invention.
; main points of the present invention are; at Circuit tuning, between biasing adjustment part and sensitivity adjustment portion, the buffer circuits (buffer circuit) that impedance is converted is set, so that the output of biasing adjustment part can not be subject to the impact of the circuit state of sensitivity adjustment portion.Therefore thus, because the output of biasing adjustment part can not be subject to the impact of the circuit state of sensitivity adjustment portion, can get rid of from biasing set-up procedure the impact of sensitivity adjustment step, thereby can disposable precision adjust well biasing and sensitivity.Below with reference to accompanying drawing, current sensor of the present invention is described.
Fig. 1 means the schematic diagram of the configuration example of the magnetic balancing current sensor that present embodiment is related.Fig. 2 means the circuit diagram of the configuration example of the current sensor that present embodiment is related.As shown in Figure 1, the current sensor 1 of present embodiment be configured in circulation determined electric current I conductor (current path) 2 near.As shown in Figure 1 and Figure 2, current sensor 1 comprises following key element and forms: the magnetoelectricity translation circuit 11 that the caused induced field A of determined electric current I is transformed into electric power; The buffer circuits (buffer amplifier circuit) 12 being connected with magnetoelectricity translation circuit 11; Be connected, be used in the Circuit tuning 13 in biasing and the adjustment of sensitivity with buffer circuits 12.
Magnetoelectricity translation circuit 11 comprises: bridge circuit 111, differential/current amplifier (voltage current transformating circuit) 112, tickler 113 and I/V amplifier (amplifying circuit, current-voltage conversion circuit) 114.
In magnetoelectricity translation circuit 11, bridge circuit 111 comprises 4 magneto-resistance effect element M1～M4 and forms, thereby can detect the caused induced field A of determined electric current I.Magneto-resistance effect element M1～M4 is by applying GMR (Giant Magneto Resistance, giant magnetoresistance) element that external magnetic field allows resistance value change, TMR (Tunnel Magneto Resistance, tunnel magneto) element etc.Can realize by the bridge circuit 111 that comprises magneto-resistance effect element M1～M4 the current sensor 1 of the magnetic balance type of the caused induced field A of the energy determined electric current I of high-sensitivity detection.
In bridge circuit 111, in the tie point connection of magneto-resistance effect element M1, M3, give supply voltage V
ddpower supply (voltage source).In addition, in the tie point connection of magneto-resistance effect element M2, M4, give the ground voltage GND ground connection of (0V).From the tie point of magneto-resistance effect element M1, M2, take out the 1st output Out1 of bridge circuit 111, from the tie point of magneto-resistance effect element M3, M4, take out the 2nd output Out2 of bridge circuit 111.The voltage difference of these 2 outputs forms accordingly with the magnetic field that is added in bridge circuit 111.In addition, bridge circuit 111 also can comprise the formations such as fixed resistive element that do not allow resistance value change because of external magnetic field.
Rear class at bridge circuit 111 connects differential/current amplifier (amplifying circuit) 112, and it amplifies the 1st output Out1 of bridge circuit 111 and voltage difference the generation current of the 2nd output Out2.That is, differential/current amplifier 112 produces the electric current corresponding with the magnetic field that is added in bridge circuit 111 according to the 1st output Out1 of bridge circuit 111 with the voltage difference of the 2nd output Out2.
Rear class at differential/current amplifier 112 connects tickler 113.Tickler 113 for example consists of the conductive pattern of circinate plane.By making the electric current (feedback current) of Self-differential/current amplifier 112 to flow to this conductive pattern, can produce the reverse offset magnetic field B corresponding with the caused induced field A of determined electric current I.But the shape of tickler 111 etc. is not particularly limited to this.
At tickler 113, connect the I/V amplifier (current-voltage conversion circuit) 114 that feedback current is transformed into voltage.This I/V amplifier 114 comprises and has the operational amplifier 114a of 2 input ends and 1 output terminal and form, and a side of its input end is connected with tickler 113.The tie point of 2 resistive element 115a, 115b that the resistance value that the opposing party's of operational amplifier 114a input end is connected with one end separately equates connects.In addition, the resistance value of resistive element 115a, 115b also can be different.Supply voltage V is given in other end connection at resistive element 115a
ddpower supply, at the other end of resistive element 115b, connect and give the ground voltage GND ground connection of (0V).Thus the opposing party's of operational amplifier 114a input end is given and is equivalent to supply voltage V
dd1/2 reference voltage.The output terminal of operational amplifier 114a is situated between and is connected with the opposing party's of operational amplifier 114a input end by resistive element 114b.The output of this operational amplifier 114a becomes the output of I/V amplifier 114.
In this magnetoelectricity translation circuit 11, when bridge circuit 111 is subject to the caused induced field A of determined electric current I, corresponding to this, produce the 1st output Out1 and the 2nd output Out2 voltage difference.Now, differential current amplifier 112 makes to produce and flow to tickler 113 with the corresponding electric current of voltage difference.When current direction tickler 113, at the generation offset magnetic field B of surrounding of tickler 113, come to offset with the caused induced field A of determined electric current I.The electric current that flows through tickler 113 is transformed into voltage by I/V amplifier 114.Under the equilibrium state offseting at induced field A and offset magnetic field B, from the voltage of I/V amplifier 114 outputs, become the size corresponding with determined electric current I.
The output terminal of I/V amplifier 114, be that the output terminal of magnetoelectricity translation circuit 11 is connected with the input end of buffer circuits (buffer amplifier circuit) 12.Buffer circuits 12 consists of the operational amplifier with 2 input ends and 1 output terminal, and the output terminal of I/V amplifier 114 is connected with the input end of one side.
At the opposing party's of buffer circuits 12 input end and output terminal, connect biasing (side-play amount of the reference value of the sensor output while being 0A from determined electric current) for adjusting current sensor 1 and the Circuit tuning 13 of sensitivity.Thus, the Circuit tuning 13 that can be connected with the input end with the opposing party and output terminal is adjusted the output voltage of the magnetoelectricity translation circuit 11 of the input end that is applied to a side, and exports from output terminal.
Impedance between 2 input ends of buffer circuits 12, the high degree that can not interfere with the circuit being connected with a side input end to the circuit being connected with the opposing party's input end.That is the be adjusted high impedance input of effect of adjustment state of circuit 13 of the voltage that, buffer circuits 12 is configured to the output terminal that does not make magnetoelectricity translation circuit 11.In other words, can make magnetoelectricity translation circuit 11 separated with Circuit tuning 13 by buffer circuits 12.
In addition, in buffer circuits 12, input end can not interfere with the degree of the circuit being connected with input end with the impedance height between output terminal to the circuit being connected with output terminal.That is the voltage that, buffer circuits 12 is configured to the output terminal that does not make magnetoelectricity translation circuit 11 is subject to the high impedance of effect of voltage of the output terminal of buffer circuits 12.The voltage of the output terminal of buffer circuits 12 does not bring impact to the voltage of a side's who is connected with magnetoelectricity translation circuit 11 input end.Thus, the output voltage of magnetoelectricity translation circuit 11 can not be subject to the impact of the circuit that is connected with the rear class of buffer circuits 12.Its result, can prevent from being subject to the impact of the circuit that is connected with the rear class of buffer circuits 12 and allow the output voltage change of magnetoelectricity translation circuit 11, the situation that amperometric determination precision reduces.
Circuit tuning 13 by biasing adjust use biasing adjustment part (the 1st adjustment part) 131, with biasing adjustment part 131 buffer circuits (buffer circuit) 132 being connected and the sensitivity adjustment portion being connected with buffer circuits 132 (the 2nd adjustment part) 133 formations.
Biasing adjustment part 131 comprises the adjusting resistance 131a that 2 resistive elements are connected in parallel and the adjusting resistance 131b that 2 resistive elements are connected in parallel.One end of adjusting resistance 131a is connected with one end of adjusting resistance 131b, its tie point is connected as the biasing output terminal of adjustment part 131 and the buffer circuits of rear class 132.The other end at adjusting resistance 131a connects power supply, the other end connection ground connection of adjusting resistance 131b.To buffer circuits 132, give the voltage by the resistance value decision of adjusting resistance 131a, 131b thus.
In biasing adjustment part 131, the resistive element of the side in 2 resistive elements of formation adjusting resistance 131a, 131b, is configured to when revisal and appends.Thus, can append the combined resistance value that resistive element regulates adjusting resistance 131a, 131b, thereby adjust the biasing of current sensor 1.The in the situation that of this formation, only append resistive element and just can carry out easily revisal.In addition, adjusting resistance 131a, 131b also can be configured to and can exchange resistive element.In addition, the formation of adjusting resistance 131a, 131b is not limited to the formation that 2 resistive elements are connected in parallel, and can also change aptly.Also can with single resistive element, realize adjusting resistance 131a, 131b respectively.
Buffer circuits 132 consists of the operational amplifier with 2 input ends and 1 output terminal, and the biasing output terminal of adjustment part 131 and the input end of one side are connected.The output terminal of buffer circuits 132 is connected with the opposing party's input end.Thus, form the voltage follower circuit of the output voltage corresponding with the output voltage of biasing adjustment part 131.
The input end that connects sensitivity adjustment portion 133 at the output terminal of buffer circuits 132.In buffer circuits 132, input end can not interfere with the degree of the circuit being connected with input end with the impedance height between output terminal to the circuit being connected with output terminal.In addition, the voltage that buffer circuits 132 is configured to the output terminal of the adjustment part 131 that do not make to setover be subject to sensitivity adjustment portion 133 input end electric current impact carry out impedance transformation.The electric current of the output terminal being connected with sensitivity adjustment portion 133 brings impact can to the voltage of a side's who is connected with biasing adjustment part 131 input end.
Thus, the output of biasing adjustment part 131 can not be subject to the impact of the circuit state of sensitivity adjustment portion 133.In other words, can be separated with sensitivity adjustment portion 133 by buffer circuits 132 adjustment part 131 that makes to setover.Its result, can make to setover adjustment part 131 and sensitivity adjustment portion 133 optimizations can disposable precision be adjusted biasing and sensitivity simultaneously well.In addition, the optimization of biasing adjustment part 131 and sensitivity adjustment portion 133 does not need simultaneously strictly speaking.For example, do not clip setover the continuously situation of adjustment of adjustment part 131 and sensitivity adjustment portion 133 of determination step between being also included in.
Sensitivity adjustment portion 133 comprises the adjusting resistance 133a that 2 resistive elements are connected in parallel and the adjusting resistance 133b that 2 resistive elements are connected in parallel.One end of adjusting resistance 133a is connected with one end of adjusting resistance 133b, and this tie point is connected with the opposing party's of buffer circuits 12 input end.The output terminal that connects buffer circuits 132 at the other end of adjusting resistance 133a.The output terminal that connects buffer circuits 12 at the other end of adjusting resistance 133b.
In sensitivity adjustment portion 133, the resistive element of the side in 2 resistive elements of formation adjusting resistance 133a, 133b is configured to when revisal and appends.Thus, can append the combined resistance value that resistive element regulates adjusting resistance 133a, 133b, adjust the sensitivity of current sensor 1.The in the situation that of this formation, only append a resistive element and just can carry out easily revisal.In addition, adjusting resistance 131a, 131b also can be configured to and can exchange resistive element.In addition, the formation of adjusting resistance 133a, 133b is not limited to the formation that 2 resistive elements are connected in parallel, and can carry out suitable change may.Also can with single resistive element, realize adjusting resistance 133a, 133b respectively.
As described above, the tie point of adjusting resistance 133a, 133b is connected with the opposing party's of buffer circuits 12 input end, connects the output terminal of buffer circuits 12 at the other end of adjusting resistance 133b.Thus, buffer circuits 12 can be adjusted the output of magnetoelectricity translation circuit 11 by Circuit tuning 13, and exports from output terminal.The output of this buffer circuits 12 becomes the output of current sensor 1.
Next biasing adjustment and sensitivity adjustment in current sensor 1 are described.In the current sensor 1 forming as described above, the magnitude of voltage V of the output terminal of I/V amplifier 114
iVby following formula (1), characterize.In formula (1), V
refrepresent to give the opposing party's of operational amplifier 114a the magnitude of voltage (=V of reference voltage of input end
dd/ 2), R
sthe resistance value that represents resistive element 114b, I
coilthe current value of the feedback current of tickler 113 is flow through in expression.
[several 1]
(formula 1)
V
IV＝V
ref-R
s×I
coil
In addition, the magnitude of voltage V of the output terminal of buffer circuits 12
outby following formula (2), characterize.At formula (2), V
ofsthe magnitude of voltage that represents the output terminal of buffer circuits 132, R
athe resistance value that represents the adjusting resistance 133a of sensitivity adjustment portion 133, R
bthe resistance value that represents the adjusting resistance 133b of sensitivity adjustment portion 133.
[several 2]
(formula 2)
In addition, the magnitude of voltage V of the output terminal of buffer circuits 132
ofsby following formula (3), characterize.In formula (3), R
cthe resistance value that represents the adjusting resistance 131a of biasing adjustment part 131, R
dthe resistance value that represents the adjusting resistance 131b of biasing adjustment part 131.
[several 3]
(formula 3)
According to formula (1)～formula (3), the magnitude of voltage V of the output terminal of buffer circuits 12
outbecome following formula (4) such.
[several 4]
(formula 4)
Shown in (4), the magnitude of voltage V of the output terminal of buffer circuits 12
outuse the resistance value R of the adjusting resistance 133a of sensitivity adjustment portion 133
a, adjusting resistance 133b resistance value R
b, biasing adjustment part 131 the resistance value R of adjusting resistance 131a
c, adjusting resistance 131b resistance value R
dcharacterize.Thus, can be by measuring the output voltage values V of different a plurality of states
outthereby, decide the resistance value of adjusting resistance 131a, 131b, 133a, 133b to be suitable for being made as sensory characteristic and the biasing characteristic of object.
The example of method of adjustment is more specifically described.First, as shown in following formula (5), by the resistance value R of the adjusting resistance 133a of the sensitivity adjustment portion 133 of original state
a1, and the resistance value R of the adjusting resistance 133b of the sensitivity adjustment portion 133 of original state
b1set equally.
[several 5]
(formula 5)
R
a1＝R
b1
At this moment, the magnitude of voltage V of the output terminal of buffer circuits 132
ofsby following formula (6), characterize.
[several 6]
(formula 6)
In addition, flowing through electric current and the bias current that the feedback current of tickler 113 produces by the induction by induced field forms.Thus, current value I
coilas shown in following formula (7), become the caused current value I of induction
senswith bias current value I
ofssum.
[several 7]
(formula 7)
I
coil＝I
sens+I
ofs
The target sensitivity G of (current value of determined electric current is 100A) while in addition, setting 100A mensuration
set(mV/A).G
setby following formula (8), characterize.G
setcharacterize the output of current sensor 1 with respect to the ratio of the current value of the determined electric current of magnitude of voltage.In formula (8), I
sens(100) represent that determined electric current is the current value producing by induction in the situation of 100A, R
a2the resistance value (for reaching the resistance value of the adjusting resistance 133a of target sensitivity) that represents the adjusting resistance 133a of the sensitivity adjustment portion 133 after adjusting, R
b2the resistance value (for reaching the resistance value of the adjusting resistance 133b of target sensitivity) that represents the adjusting resistance 133b of the sensitivity adjustment portion 133 after adjusting.
[several 8]
(formula 8)
Next, under above-mentioned original state, measure the output voltage values V in the situation that determined electric current is 0A, 100A
out.Determined electric current is the output voltage values V in the situation of 0A
out(0) the output voltage values V and in the determined electric current situation that is 100A
out(100) use respectively following formula (9), (10) to characterize.
[several 9]
(formula 9)
[several 10]
(formula 10)
According to formula (9), (10), I
ofsand I
sens(100) as following formula (11), (12), ask for.
[several 11]
(formula 11)
[several 12]
(formula 12)
According to formula (8), for reaching the R of target sensitivity
a2, R
b2such as following formula (13) characterizes like that.Thereby, can decide for reaching the R of target sensitivity according to above-mentioned formula (12) and following formula (13)
a2, R
b2relation.
[several 13]
(formula 13)
On the other hand, in the situation that adjustment current sensor 1 makes to be biased to zero, at adjustment current sensor 1, making Vout (0) is the desirable output V under zero magnetic field
ddin/2 situation, about output voltage values V
out(0), following formula (14) is set up.In formula (14), R
c2the resistance value of the adjusting resistance 131a of the biasing adjustment part 131 after represent adjusting (for reaching the resistance value of adjusting resistance 131a of the biasing of target), R
d2the resistance value of the adjusting resistance 131b of the biasing adjustment part 131 after represent adjusting (for reaching the resistance value of adjusting resistance 131b of the biasing of target).
[several 14]
(formula 14)
According to formula (14), for reaching the R of the biasing of target
c2, R
d2as following formula (15), characterize.Thereby, can determine for reaching the R of the biasing of target according to above-mentioned formula (11) and following formula (15)
c2, R
d2relation.
[several 15]
(formula 15)
Afterwards, append the resistive element that forms adjusting resistance 131a, 131b, 133a, 133b, to realize the resistance value (R calculating as described above
a2, R
b2, R
c2, R
d2) relation.Thus, sensory characteristic and the biasing characteristic that can adjust current sensor 1 realize biasing characteristic and the sensory characteristic that is made as object.
As described above, the current sensor of present embodiment 1 uses the buffer circuits 132 that carries out impedance transformation, so that the voltage of the output terminal of biasing adjustment part 131 can not be subject to the impact of electric current of the input end of sensitivity adjustment portion 133.More specifically, forming between biasing adjusting resistance 131a, the 131b of adjustment part 131 and adjusting resistance 133a, the 133b of formation sensitivity adjustment portion 133, arranging between input/output terminal is the buffer circuits 132 of high impedance.Thus, the output adjustment biasing set-up procedure of carrying out by biasing adjustment part 131 can not be subject to the impact of the sensitivity adjustment step of being undertaken by the output adjustment of sensitivity adjustment portion 133.Thus, can disposable precision adjust well biasing and sensitivity.
In addition, the current sensor 1 of present embodiment, therefore can be by the reference voltage V of current-voltage conversion owing to having buffer circuits 12 at magnetoelectricity translation circuit 11 and 13 of Circuit tunings
refremain on V
dd/ 2.Thus, can make according to V
ddor GND and V
refbetween potential difference (PD) and the maximal value of the coil current that determines of coil resistance be that maximal value on circuit forms is (with V
ddthe current value of/2 correspondences).Thus, even in the situation that the caused induced field of determined electric current is larger, also can flow through large electric current and the magnetic field that allows magneto-resistance effect element receive is little at coil.Its result, can prevent the magnetic hysteresis of the magneto-resistance effect element that causes because of large induced field, can prevent from using the current precision variation of the current sensor 1 of magneto-resistance effect element.
Next, the configuration example of adjusting resistance 133a, 133b is described with reference to figure 3.Fig. 3 means the circuit diagram of the configuration example of adjusting resistance 133a, 133b.In addition, the configuration example of adjusting resistance 131a, 131b is identical with the configuration example of adjusting resistance 133a, 133b, can use the formation shown in Fig. 3.
Fig. 3 A represent adjusting resistance 133a by single resistive element form, adjusting resistance 133b is by 2 examples that resistive element forms that are connected in parallel.In this situation, more meticulously the resistance value of adjusting resistance 133b is adjusted with adjusting resistance 133a phase specific energy.In addition, also can form adjusting resistance 133b with single resistive element, with 2 resistive elements that are connected in parallel, form adjusting resistance 133a.Fig. 3 B represents that adjusting resistance 133a, 133b are by 2 examples that resistive element forms that are connected in parallel.In this case, can carry out together careful adjustment to the resistance value of adjusting resistance 133a, 133b.
Fig. 3 C represents that adjusting resistance 133a, 133b are by 3 examples that resistive element forms that are connected in parallel.In this case, can further to the resistance value of adjusting resistance 133a, 133b, adjust meticulously.In addition, the quantity of the resistive element of formation adjusting resistance 133a, 133b also can be for more than 4.The quantity of the resistive element that can be connected in parallel by increase more meticulously the resistance value of adjusting resistance 133a, 133b is adjusted.Fig. 3 D represents that adjusting resistance 133a, 133b are by 2 resistive elements that are connected in parallel and 1 example that resistive element forms being connected in series.In this case, by appending or change the resistive element being connected in parallel, can carry out inching to the resistance value of adjusting resistance 133a, 133b.
So, the current sensor 1 of present embodiment can be adjusted the resistance value of adjusting resistance 131a, 131b, 133a, 133b by forming the combination of the resistive element of adjusting resistance 131a, 131b, 133a, 133b, and biasing and sensitivity are adjusted.Thus, in the current sensor 1 of present embodiment, no longer need to use resistance value such resistance that gradually changes.For example, can as bulk resistor etc., not be subject to vibration and time dependent impact.In addition, can as laser trimming etc., need to when revisal, not use expensive device.Thus, can realize at low cost stable revisal.
In addition, the present invention is not limited to above-mentioned embodiment, can carry out various changes and implement.For example, as for adjusting the adjusting resistance of biasing and sensitivity, also can use the resistance of ICization, thereby can switch the resistance being connected in parallel with switch.In addition, as the operational amplifier that forms current sensor, can use the formation of ICization.In this, operational amplifier is the current sensor 1 of the embodiment of 4, can encapsulate to realize with 1 IC that comprises 2 or 4 operational amplifiers, more satisfactory.In addition, in the above-described embodiment, the situation that the determined electric current of take is 100A is adjusted sensitivity as benchmark, but can set arbitrarily the current value that becomes benchmark.
In addition, as long as do not change inventive concept, can change the annexation, size of each element in above-mentioned embodiment etc.In addition, the energy proper combination such as the formation shown in above-mentioned embodiment, method is implemented.In addition, the present invention can not depart from the scope of the present invention suitable change and implements.
In industry, utilize possibility
Current sensor of the present invention is such as using by the size of electric current in order to survey the direct motor drive of electric automobile and hybrid electric vehicle etc.
The Japanese publication Patent 2012-4016 of the application based on application on January 12nd, 2012.Its content is all contained in this.
Claims (according to the modification of the 19th of treaty)
1. a current sensor, is characterized in that, possesses:
The magnetoelectricity translation circuit that magnetic field is transformed into voltage and exports from output terminal;
The buffer amplifier circuit being connected with the output terminal of described magnetoelectricity translation circuit; With
Adjust the Circuit tuning of the output of described buffer amplifier circuit,
Described Circuit tuning has:
From output terminal, export the 1st adjustment part of adjusted voltage;
Can adjust the 2nd adjustment part of the magnification of described buffer amplifier circuit; With
Be located at the output terminal of described the 1st adjustment part and the buffer circuit between described the 2nd adjustment part,
By the voltage of described the 1st adjustment part output, adjust the biasing of the output of described buffer amplifier circuit.
2. current sensor according to claim 1, is characterized in that,
Described buffer amplifier circuit is to possess the 1st input end being connected with described magnetoelectricity translation circuit, the 2nd input end being connected with described Circuit tuning and the operational amplifier of output terminal,
Described the 2nd adjustment part has the 3rd adjusting resistance and the 4th adjusting resistance being connected in series with described buffer circuit, and described buffer amplifier circuit and described the 4th adjusting resistance are connected in parallel.
3. current sensor according to claim 1, is characterized in that,
Described the 1st adjustment part has the 1st adjusting resistance and the 2nd adjusting resistance being connected in series between voltage source and ground connection, and described the 1st adjusting resistance and described the 2nd tie point of adjusting resistance and the input end of described buffer circuit are connected.
4. current sensor according to claim 1, is characterized in that,
Described magnetoelectricity translation circuit possesses:
The bridge circuit with the magneto sensor that electrical specification changes corresponding to magnetic field;
The amplifying circuit that the magnetic field that input end is connected, measures corresponding to described bridge circuit with described bridge circuit produces electric current;
The coil that one end is connected with the output terminal of described amplifying circuit; With
Be connected, produce and flow through the current-voltage conversion circuit of the corresponding voltage of electric current of described coil with the other end of described coil,
Described amplifying circuit is controlled at the electric current that described coil midstream is logical, produces and will be applied to the magnetic field of the magnetic field cancellation of described magneto sensor.
5. current sensor according to claim 4, is characterized in that,
Described magneto sensor is magneto-resistance effect element.
6. current sensor according to claim 1, is characterized in that,
Described buffer circuit is operational amplifier.
7. (revise afterwards) a kind of method of adjustment of current sensor, described current sensor possesses:
The magnetoelectricity translation circuit that magnetic field is transformed into voltage and exports from output terminal;
The buffer amplifier circuit being connected with the output terminal of described magnetoelectricity translation circuit; With
Adjust the Circuit tuning of the output of described buffer amplifier circuit,
Described Circuit tuning has:
From output terminal, export the 1st adjustment part of adjusted voltage;
Can adjust the 2nd adjustment part of the magnification of described buffer amplifier circuit; With
Be located at the buffer circuit between the output terminal of described the 1st adjustment part and the input end of described the 2nd adjustment part,
The method of adjustment of described current sensor possesses:
2 states different to the current value of the determined electric current circulating in the current path of determination object, the step of the magnitude of voltage of the output terminal of mensuration buffer amplifier circuit; With
2 magnitudes of voltage of the output terminal of the buffer amplifier circuit based on described mensuration are adjusted the step of the output of described the 1st adjustment part and described the 2nd adjustment part simultaneously.
Claims (7)
1. a current sensor, is characterized in that, possesses:
The magnetoelectricity translation circuit that magnetic field is transformed into voltage and exports from output terminal;
The buffer amplifier circuit being connected with the output terminal of described magnetoelectricity translation circuit; With
Adjust the Circuit tuning of the output of described buffer amplifier circuit,
Described Circuit tuning has:
From output terminal, export the 1st adjustment part of adjusted voltage;
Can adjust the 2nd adjustment part of the magnification of described buffer amplifier circuit; With
Be located at the output terminal of described the 1st adjustment part and the buffer circuit between described the 2nd adjustment part,
By the voltage of described the 1st adjustment part output, adjust the biasing of the output of described buffer amplifier circuit.
2. current sensor according to claim 1, is characterized in that,
Described buffer amplifier circuit is to possess the 1st input end being connected with described magnetoelectricity translation circuit, the 2nd input end being connected with described Circuit tuning and the operational amplifier of output terminal,
Described the 2nd adjustment part has the 3rd adjusting resistance and the 4th adjusting resistance being connected in series with described buffer circuit, and described buffer amplifier circuit and described the 4th adjusting resistance are connected in parallel.
3. current sensor according to claim 1, is characterized in that,
Described the 1st adjustment part has the 1st adjusting resistance and the 2nd adjusting resistance being connected in series between voltage source and ground connection, and described the 1st adjusting resistance and described the 2nd tie point of adjusting resistance and the input end of described buffer circuit are connected.
4. current sensor according to claim 1, is characterized in that,
Described magnetoelectricity translation circuit possesses:
The bridge circuit with the magneto sensor that electrical specification changes corresponding to magnetic field;
The amplifying circuit that the magnetic field that input end is connected, measures corresponding to described bridge circuit with described bridge circuit produces electric current;
The coil that one end is connected with the output terminal of described amplifying circuit; With
Be connected, produce and flow through the current-voltage conversion circuit of the corresponding voltage of electric current of described coil with the other end of described coil,
Described amplifying circuit is controlled at the electric current that described coil midstream is logical, produces and will be applied to the magnetic field of the magnetic field cancellation of described magneto sensor.
5. current sensor according to claim 4, is characterized in that,
Described magneto sensor is magneto-resistance effect element.
6. current sensor according to claim 1, is characterized in that,
Described buffer circuit is operational amplifier.
7. a method of adjustment for current sensor, is characterized in that, possesses:
Magnetic field is transformed into voltage and from output terminal, exports the magnetoelectricity translation circuit of this voltage;
For adjusting the Circuit tuning of voltage of the output terminal of described magnetoelectricity translation circuit; With
The buffer amplifier circuit being connected with the output terminal of described magnetoelectricity translation circuit,
Described Circuit tuning possesses:
From output terminal, export the 1st adjustment part of adjusted voltage; With
Be located at the buffer circuit between the output terminal of described the 1st adjustment part and the input end of described the 2nd adjustment part,
The method of adjustment of described current sensor possesses:
2 states different to the current value of the determined electric current circulating in the current path of determination object, the step of the magnitude of voltage of the output terminal of mensuration buffer amplifier circuit; With
2 magnitudes of voltage of the output terminal of the buffer amplifier circuit based on described mensuration are adjusted the step of the output of described the 1st adjustment part and described the 2nd adjustment part simultaneously.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012-004016 | 2012-01-12 | ||
| JP2012004016 | 2012-01-12 | ||
| PCT/JP2012/083931 WO2013105451A1 (en) | 2012-01-12 | 2012-12-27 | Current sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104040362A true CN104040362A (en) | 2014-09-10 |
| CN104040362B CN104040362B (en) | 2016-05-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201280066547.0A Active CN104040362B (en) | 2012-01-12 | 2012-12-27 | Current sensor |
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| Country | Link |
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| JP (1) | JP5891516B2 (en) |
| CN (1) | CN104040362B (en) |
| WO (1) | WO2013105451A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109564248A (en) * | 2016-07-22 | 2019-04-02 | 旭化成微电子株式会社 | Current sensor |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6446859B2 (en) * | 2014-06-27 | 2019-01-09 | ヤマハ株式会社 | Integrated circuit |
| JP2018040763A (en) * | 2016-09-09 | 2018-03-15 | 旭化成エレクトロニクス株式会社 | Electric current sensor, and sensitivity adjusting method |
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Also Published As
| Publication number | Publication date |
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| WO2013105451A1 (en) | 2013-07-18 |
| JP5891516B2 (en) | 2016-03-23 |
| CN104040362B (en) | 2016-05-04 |
| JPWO2013105451A1 (en) | 2015-05-11 |
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