CN216144871U - Temperature compensation current sensor - Google Patents
Temperature compensation current sensor Download PDFInfo
- Publication number
- CN216144871U CN216144871U CN202122076936.0U CN202122076936U CN216144871U CN 216144871 U CN216144871 U CN 216144871U CN 202122076936 U CN202122076936 U CN 202122076936U CN 216144871 U CN216144871 U CN 216144871U
- Authority
- CN
- China
- Prior art keywords
- temperature
- magnetic
- current sensor
- sensing chip
- magnetic sensing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
A temperature compensated current sensor comprising: the magnetic sensor comprises a magnetic gathering ring, a feedback coil wound on the magnetic gathering ring and a magnetic sensing chip arranged at the notch or the opening of the magnetic gathering ring, wherein the magnetic sensing chip comprises magneto-resistance elements connected into a full-bridge structure and a thermistor integrated in the magnetic sensing chip; the thermistor is connected with the input end of the temperature acquisition circuit, the output end of the temperature acquisition circuit is connected with the input terminal of the magnetic sensing chip to supply power for the magnetic sensing chip, and the magnetic sensing chip is connected with the feedback coil through the magnetic balance circuit. The temperature compensation circuit directly drives the full-bridge circuit formed by the magneto-resistance elements, the temperature compensation information is coupled to the magnetic field sensor to perform temperature drift compensation of the current sensor, and an additional temperature compensation circuit is not needed, so that the cost is reduced.
Description
Technical Field
The utility model belongs to the technical field of current sensing, and particularly relates to a current sensor capable of performing temperature compensation.
Background
The magnetic balance type current sensor based on zero magnetic flux detection has the advantages of high sensitivity, wide measurement range and the like, is widely applied to the field of current measurement, and can realize the detection of current by utilizing a magnetic field generated by the current. However, due to the influence of the temperature characteristics of the magnetic field sensor and the feedback coil winding, the sensitivity of the magnetic balance type current sensor based on zero magnetic flux detection is influenced by the change of the environmental temperature, and further the measurement accuracy of the current sensor is influenced. Temperature drift compensation of the current sensor is therefore usually required to ensure its measurement accuracy at different temperatures.
The output of the current sensor is compensated through the thermistor, so that the temperature drift of the magnetic field sensor can be effectively reduced, and the precision of the current sensor is improved. For example, the chinese patent application with publication number CN111650429A discloses a temperature compensation current sensor. However, temperature drift compensation using a thermistor requires a temperature compensation circuit such as an addition circuit or a multiplication circuit to be constructed to compensate the output of the current sensor. The temperature compensation circuit will couple a temperature compensation amount into the output of the sensor. Since the temperature drift signal of the magnetic field sensor is amplified by the current sensor sensitivity gain, the required temperature compensation amount is increased, and a thermosensitive element is required to have a larger temperature coefficient, or an additional amplifying circuit is constructed, thereby increasing the cost and power consumption of the magnetic field sensor.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a temperature compensation current sensor with simpler structure and lower cost.
In order to achieve the purpose, the utility model adopts the following technical solutions:
a temperature compensated current sensor comprising: the magnetic sensor comprises a magnetic gathering ring, a feedback coil wound on the magnetic gathering ring and a magnetic sensing chip arranged at the notch or the opening of the magnetic gathering ring, wherein the magnetic sensing chip comprises magneto-resistance elements connected into a full-bridge structure and a thermistor integrated in the magnetic sensing chip; the thermistor is connected with the input end of the temperature acquisition circuit, the output end of the temperature acquisition circuit is connected with the input terminal of the magnetic sensing chip to supply power for the magnetic sensing chip, and the magnetic sensing chip is connected with the feedback coil through the magnetic balance circuit.
Optionally, the magnetic balance circuit includes a differential voltage sampling circuit and a power amplification circuit that are connected in sequence, the differential voltage sampling circuit is used for collecting the differential voltage signal output by the magnetic sensing chip, and the power amplification circuit generates the current output to the feedback coil according to the differential voltage signal, so that the feedback coil generates the feedback magnetic field.
Optionally, the magnetoresistance element and the thermistor are integrated in different regions of the magnetic sensor chip, and are independent of each other, and are respectively used for measuring a magnetic field and temperature.
Optionally, the thermistor is a ruthenium resistor.
Optionally, the magnetoresistive element is a TMR cell or a GMR cell.
Optionally, the magnetoresistive element is a TMR cell, the TMR cell comprising at least a pinned layer, a free layer and a non-magnetic layer, the non-magnetic layer being located between the pinned layer and the free layer.
Furthermore, the TMR unit also comprises a top electrode layer positioned on the uppermost layer and a lower electrode layer positioned on the lowermost layer.
Optionally, the magnetism gathering ring is an arc-shaped or C-shaped silicon steel sheet or permalloy sheet or a nano wafer.
Optionally, the magnetic sensing chip includes 4 groups of tunnel junction magneto resistance elements, and 4 groups of tunnel junction magneto resistance elements adopt magnetron sputtering technique deposit on the substrate and connect into the full-bridge structure, tunnel junction magneto resistance element is located 4 bridge arms of full-bridge structure respectively, all is provided with a connecting terminal between two adjacent bridge arms, totally 4 connecting terminals, and one of them pair of connecting terminal is as input terminal, and another is as output terminal to connecting terminal.
Further, the thermistor and the tunnel junction magneto-resistance element are integrated on the same substrate.
According to the technical scheme, the temperature information is converted into the current or voltage signal through the temperature acquisition circuit, the current or voltage signal output by the temperature acquisition circuit is used for driving the full-bridge circuit formed by the magneto-resistor elements to supply power to the full-bridge circuit, the circuit structure is simpler, the power consumption can be reduced, the full-bridge circuit is directly driven by the temperature acquisition circuit, the temperature compensation information is coupled into the magnetic field sensor to perform temperature drift compensation of the current sensor, and the temperature compensation circuit does not need to be additionally constructed, so that the cost is reduced. In addition, compared with the mode of introducing the temperature compensation quantity after the closed loop in the prior art, the temperature feedback quantity introduced after the closed loop cannot inhibit temperature interference, but the temperature compensation quantity introduced before the closed loop of the current sensor is introduced, namely the output of the temperature sensor is adopted to drive the TMR chip, and then the TMR chip and the feedback coil are utilized to construct the temperature compensation quantity introducing mode of the closed loop current sensor, so that the controlled quantity deviating from the specified value can be controlled to eliminate deviation in the closed loop process, and the stability and the sensitivity of the sensor can be improved.
Drawings
In order to illustrate the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained by those skilled in the art without inventive effort.
FIG. 1 is a schematic structural diagram of a current sensor according to an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of a magnetic sensor chip according to an embodiment of the present invention;
FIG. 3 is a block circuit diagram of a current sensor according to an embodiment of the present invention;
FIG. 4 is a graph of the output of a thermistor through a temperature acquisition circuit as a function of temperature in accordance with an embodiment of the present invention;
FIG. 5 is a graph of current sensor sensitivity and current sensor sensitivity versus temperature without temperature compensation in accordance with an embodiment of the present invention.
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Detailed Description
The utility model will be described in detail below with reference to the accompanying drawings, wherein for the purpose of illustrating embodiments of the utility model, the drawings showing the structure of the device are not to scale but are partly enlarged, and the schematic drawings are only examples, and should not be construed as limiting the scope of the utility model. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is provided solely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
Referring to fig. 1, 2 and 3, the temperature compensation current sensor of the present embodiment includes a feedback coil 1, a magnetism collecting ring 2, a magnetic sensing chip 3, a magnetic balance circuit 4, a temperature acquisition circuit 5 and a current sampling circuit 6. The feedback coil 1 is wound on the poly-magnetic ring 2 and used for generating a feedback magnetic field. The magnetism gathering ring 2 can be an annular opening-closing structure formed by a pair of arc iron cores arranged oppositely or a fixed structure formed by a C-shaped iron core. The magnetism gathering ring 2 can be made of silicon steel sheets, permalloy, nanocrystalline and other magnetic materials. A notch 2a is arranged on the magnetism gathering ring 2, the magnetic sensing chip 3 is arranged at the notch 2a (or opening) of the magnetism gathering ring 2, and the magnetic sensing chip 3 is used for magnetic field detection.
The magnetic sensor chip 3 includes a magnetoresistive sensor unit including a magnetoresistive element such as a TMR cell or a GMR cell. The magnetic sensing chip 3 of the embodiment includes 4 sets of tunnel junction magnetoresistive elements (a, b, c, d), and the 4 sets of tunnel junction magnetoresistive elements are deposited on a substrate by magnetron sputtering technology and connected to form a full bridge structure. The 4 groups of tunnel junction magneto-resistance elements are respectively positioned on 4 bridge arms of a full-bridge structure, a connecting terminal is arranged between every two adjacent bridge arms, 4 connecting terminals (3a, 3b, 3c and 3d) are arranged, one pair of connecting terminals (3c and 3d) in the 4 connecting terminals are input terminals, the other pair of connecting terminals (3a and 3b) are output terminals, and the magnetic sensing chip 3 outputs differential voltage signals related to a magnetic field through the output terminals. Each group of the tunnel junction magneto-resistance elements has the same structure and at least comprises a top electrode layer, a lower electrode layer, a pinning layer, a free layer and a non-magnetic layer, wherein the non-magnetic layer is positioned between the pinning layer and the free layer. The magnetization direction of a pinning layer in the tunnel junction magneto-resistance element does not change along with the change of an external magnetic field, the magnetization direction of a free layer changes along with the change of the external magnetic field, and the resistance value of the tunnel junction magneto-resistance element changes along with the change of an included angle between the magnetization direction of the free layer and the magnetization direction of the pinning layer, so that the detection of the magnetic field is realized.
The magnetic sensing chip 3 is further integrated with a thermistor 7 on the substrate, the thermistor 7 is used for collecting temperature information of a magnetic field detection area, the thermistor 7 is preferably made of ruthenium material, and ruthenium is one of materials for preparing an electrode layer and a pinning layer of a tunnel junction magneto-resistance element (TMR), so that the thermistor 7 is integrated in the magnetic sensing chip 3. In other embodiments, the tunnel junction magnetoresistive element can be replaced by GMR, and a ruthenium material is added to the material for making the GMR cell, so that the thermistor is integrated into the chip. The thermistor 7 is connected with the input end of the temperature acquisition circuit 5 through the temperature signal connection terminals (3e, 3f), the thermistor 7 outputs sampling voltage (or sampling current) related to temperature, and the output end of the temperature acquisition circuit 5 is connected with the input terminal of the magnetic sensing chip 3, so that the voltage output by the thermistor 7 is used as the working voltage of the magnetic sensing chip 3 (magnetoresistive sensor unit), and the full-bridge circuit is in a working state. The tunnel junction magneto-resistance element and the thermistor are integrated in different regions of the magnetic sensor chip, are independent of each other, and are respectively used for measuring a magnetic field and temperature. The temperature acquisition circuit acquires temperature information of the thermistor, converts the temperature information into a voltage signal or a current signal and outputs the voltage signal or the current signal, and is used for driving a full-bridge circuit formed by the tunnel junction magneto-resistance elements.
The magnetic sensing chip 3 is connected with the magnetic balance circuit 4 through the output terminals (3a, 3b), the magnetic balance circuit 4 of the embodiment comprises a differential voltage sampling circuit 4-1 and a power amplifying circuit 4-2, and the differential voltage sampling circuit 4-1 is used forThe differential voltage signal V output by the magnetic sensing chip 3 is collectedMThe power amplifier circuit 4-2 generates a current I to be output to the feedback coil 1 based on the differential voltage signalsSo that the feedback coil 1 generates a feedback magnetic field and the current sensor reaches a magnetic equilibrium state.
The working principle of this embodiment is explained below with reference to fig. 1:
as shown in fig. 1, when the current sensor is used for measuring, a measured conductor 20 passes through the magnetic gathering ring 2, and when a current flows through the measured conductor 20, a magnetic field a is generated around the measured conductor 20; the magnetic sensing chip 3 detects the magnetic field at the notch 2a of the magnetic gathering ring 2 and outputs a differential voltage signal VM(ii) a The magnetic balance circuit 4 collects the differential voltage signal V output by the magnetic sensing chip 3MAnd adjusting the input current I of the feedback coil 2S(ii) a Feedback coil 1 at current ISUnder the action of the magnetic field generating unit, a magnetic field B is generated in the magnetism gathering ring 2; when the differential voltage signal VMWhen the magnetic flux is zero, the magnetic field a generated by the tested conductor 20 and the magnetic field B generated by the magnetic convergence ring 2 reach a magnetic balance state, and the gap 2a of the magnetic convergence ring 2 has zero magnetic flux.
The magnetic balance type current sensor prepared by using the magnetic resistance sensing unit has the output represented as: vO(t)＝VCCS (t) i, where t is the ambient temperature in which the current sensor is located, VCCThe supply voltage of the magnetoresistive sensor unit, s (t) the current sensor sensitivity, i the measured current.
The supply voltage of the magnetoresistive sensor units is provided by a temperature acquisition circuit, then:
VO(t)＝VCC(t)·S(t)·i；
taking the natural logarithm of the above formula and deriving t yields:
ln(VO(t))＝ln(VCC(t)·S(t)·i)；
when no temperature drift exists, the following conditions are satisfied:
namely:
in the formula
Is the temperature coefficient of the temperature acquisition circuit,
is the temperature coefficient of the current sensor sensitivity.
The output of the temperature acquisition circuit of this embodiment is shown in fig. 4, and it can be seen from fig. 4 that the output of the thermistor (ruthenium resistor) through the temperature acquisition circuit varies with temperature. Fig. 5 is a graph showing the sensitivity of the current sensor changing with temperature, and two curves s1 and s2 in fig. 5 respectively show the sensitivity of the temperature compensation current sensor changing with temperature according to the embodiment and the sensitivity of the current sensor changing with temperature when temperature compensation is not performed (i.e. constant voltage power supply is used instead of output power supply of the temperature acquisition circuit).
The closer the values of the temperature coefficient of the sensor sensitivity and the temperature coefficient of the temperature acquisition circuit are and the opposite signs are, the better the temperature drift compensation effect is, and when the values of the temperature coefficient of the sensor sensitivity and the temperature coefficient of the temperature acquisition circuit are equal and the opposite signs are, the best temperature drift compensation effect can be obtained. Taking the temperature coefficient of the temperature acquisition circuit and the temperature coefficient of the current sensor sensitivity under the temperature condition of 27 ℃ as an example, the temperature coefficient value of the temperature acquisition circuit at 27 ℃ is 0.1038%/° c, the temperature coefficient value of the temperature compensation current sensor sensitivity of the embodiment is-0.103%/° c, and the temperature coefficient value of the current sensor sensitivity without temperature compensation is 0.00016%/° c. As can be seen from fig. 5, after the temperature drift compensation is performed on the current sensor of this embodiment, the sensitivity coefficient during temperature change is kept close to 27 ℃.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A temperature compensated current sensor comprising: the magnetic sensor comprises a magnetic gathering ring, a feedback coil wound on the magnetic gathering ring and a magnetic sensing chip arranged at the notch or the opening of the magnetic gathering ring, wherein the magnetic sensing chip comprises magneto-resistance elements connected into a full-bridge structure and a thermistor integrated in the magnetic sensing chip;
the method is characterized in that: the thermistor is connected with the input end of the temperature acquisition circuit, the output end of the temperature acquisition circuit is connected with the input terminal of the magnetic sensing chip to supply power for the magnetic sensing chip, and the output terminal of the magnetic sensing chip is connected with the feedback coil through the magnetic balance circuit.
2. The temperature-compensated current sensor of claim 1, wherein: the magnetic balance circuit comprises a differential voltage sampling circuit and a power amplification circuit which are sequentially connected, the differential voltage sampling circuit is used for collecting differential voltage signals output by the magnetic sensing chip, and the power amplification circuit generates current output to the feedback coil according to the differential voltage signals so that the feedback coil generates a feedback magnetic field.
3. The temperature-compensated current sensor of claim 1, wherein: the magneto-resistance element and the thermistor are integrated in different areas of the magnetic sensing chip, are independent of each other, and are respectively used for measuring a magnetic field and temperature.
4. The temperature-compensated current sensor of claim 1, wherein: the thermistor is a ruthenium resistor.
5. The temperature-compensated current sensor of claim 1, wherein: the magneto-resistance element is a TMR unit or a GMR unit.
6. The temperature-compensated current sensor of claim 1, wherein: the magnetoresistive element is a TMR unit including at least a pinned layer, a free layer, and a nonmagnetic layer between the pinned layer and the free layer.
7. The temperature-compensated current sensor of claim 6, wherein: the TMR unit further comprises a top electrode layer located on the uppermost layer and a lower electrode layer located on the lowermost layer.
8. The temperature-compensated current sensor of claim 1, wherein: the magnetism gathering ring is an arc-shaped or C-shaped silicon steel sheet or a permalloy sheet or a nanometer wafer.
9. The temperature-compensated current sensor of claim 1, wherein: the magnetic sensing chip comprises 4 groups of tunnel junction magneto-resistance elements, wherein the 4 groups of tunnel junction magneto-resistance elements are deposited on a substrate by adopting a magnetron sputtering technology and are connected into a full-bridge structure, the tunnel junction magneto-resistance elements are respectively positioned on 4 bridge arms of the full-bridge structure, a connecting terminal is arranged between every two adjacent bridge arms, 4 connecting terminals are arranged, one pair of the connecting terminals serves as an input terminal, and the other pair of the connecting terminals serves as an output terminal.
10. The temperature-compensated current sensor of claim 9, wherein: the thermistor and the tunnel junction magneto-resistance element are integrated on the same substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122076936.0U CN216144871U (en) | 2021-08-31 | 2021-08-31 | Temperature compensation current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122076936.0U CN216144871U (en) | 2021-08-31 | 2021-08-31 | Temperature compensation current sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216144871U true CN216144871U (en) | 2022-03-29 |
Family
ID=80810700
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122076936.0U Active CN216144871U (en) | 2021-08-31 | 2021-08-31 | Temperature compensation current sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216144871U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115855122A (en) * | 2022-11-21 | 2023-03-28 | 珠海多创科技有限公司 | Method and device for performing temperature compensation on sensor chip and electronic equipment |
-
2021
- 2021-08-31 CN CN202122076936.0U patent/CN216144871U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115855122A (en) * | 2022-11-21 | 2023-03-28 | 珠海多创科技有限公司 | Method and device for performing temperature compensation on sensor chip and electronic equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9465056B2 (en) | Current sensor with temperature-compensated magnetic tunnel junction bridge | |
| US8519704B2 (en) | Magnetic-balance-system current sensor | |
| CN103645369B (en) | A kind of current sensor device | |
| CN103616550A (en) | Giant magnetoresistance current sensor | |
| CN101788596A (en) | Tunnel junction magneto-resistance effect principle (TMR) current sensors | |
| CN111650429A (en) | Magnetic sensing chip, temperature compensation current sensor and preparation method thereof | |
| CN111650428A (en) | Magnetic sensing chip, closed-loop feedback current sensor and preparation method thereof | |
| CN103575960A (en) | Giant magnetoresistance effect current sensor | |
| CN205210163U (en) | Huge magnetoresistive effect current sensor | |
| CN109142843A (en) | A kind of portable Intelligent Measure and Control Instrument | |
| CN111044953A (en) | Single-chip full-bridge TMR magnetic field sensor | |
| CN216144871U (en) | Temperature compensation current sensor | |
| CN112083211A (en) | Current sensor | |
| CN203630195U (en) | Giant magnetoresistance current sensor | |
| Yoon et al. | Magnetic sensor system using asymmetric giant magnetoimpedance head | |
| CN115541960A (en) | Magneto-resistance sensor, chip and preparation method of chip | |
| CN102288815B (en) | Temperature compensator for giant magneto-resistance effect current sensor | |
| CN206311652U (en) | A kind of magneto-resistor current sensor with integrated current coil | |
| CN109932670B (en) | Closed-loop TMR magnetic field measuring device based on power-on position | |
| CN112363097A (en) | Magneto-resistance sensor chip | |
| Takayama et al. | Integrated thin film magneto-impedance sensor head using plating process | |
| CN212568937U (en) | Magnetic sensing chip and closed-loop feedback current sensor | |
| CN108469594B (en) | High-precision closed-loop gradient magnetic resistance sensor | |
| CN212008887U (en) | Single-chip full-bridge TMR magnetic field sensor | |
| CN105606877B (en) | A kind of closed loop TMR current sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |