CN117420484A - Hall sensor using frequency output - Google Patents

Hall sensor using frequency output Download PDF

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Publication number
CN117420484A
CN117420484A CN202311302725.1A CN202311302725A CN117420484A CN 117420484 A CN117420484 A CN 117420484A CN 202311302725 A CN202311302725 A CN 202311302725A CN 117420484 A CN117420484 A CN 117420484A
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China
Prior art keywords
hall
frequency
voltage
hall element
circuit
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CN202311302725.1A
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Inventor
姜帅
孙恒超
方东明
杜君
李良
闻志国
季润可
陶毅
王蔓蓉
银钧
牛长胜
王祥
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Beijing Smartchip Microelectronics Technology Co Ltd
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Beijing Smartchip Microelectronics Technology Co Ltd
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Priority to CN202311302725.1A priority Critical patent/CN117420484A/en
Publication of CN117420484A publication Critical patent/CN117420484A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/07—Hall effect devices
    • G01R33/072—Constructional adaptation of the sensor to specific applications
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/007—Environmental aspects, e.g. temperature variations, radiation, stray fields

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Toxicology (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

The invention provides a Hall sensor adopting frequency output, and belongs to the technical field of sensors. The hall sensor includes: the compensation circuit is used for providing a reference voltage irrelevant to an external magnetic field; the change rule of the reference voltage along with the temperature is the same as that of the measuring circuit; the measuring circuit is used for generating Hall voltage according to the externally applied magnetic field; the device is also used for measuring the frequency of the excitation source and determining the magnitude of the external magnetic field according to the frequency of the excitation source; the subtracter is used for calculating the voltage difference value between the reference voltage and the Hall voltage and feeding back the voltage difference value to the excitation source; the measuring circuit excitation source is used for providing driving current for the measuring circuit; and the negative feedback is performed according to the voltage difference value, so that the value of the Hall voltage is always equal to the reference voltage. The invention converts the Hall voltage into a frequency signal by utilizing the frequency response characteristic of the Hall voltage to the excitation power supply, and obtains the intensity value of the magnetic field by measuring the frequency signal.

Description

Hall sensor using frequency output
Technical Field
The invention relates to the technical field of sensors, in particular to a Hall sensor adopting frequency output.
Background
A hall sensor is a magnetic sensor that can be used to measure a magnetic field by measuring a hall voltage generated in a hall device by an external magnetic field using a hall effect in a semiconductor.
The Hall sensor in the prior art obtains the size of the magnetic field through measuring the Hall voltage, but because the Hall voltage generated by the Hall sensor under the action of the magnetic field is smaller, the Hall voltage signal needs to be amplified and filtered by adopting an amplifying circuit and a filtering circuit, even so, the precision of the Hall sensor can not be very high due to the influence of device noise, so that the application scene of the Hall sensor is greatly limited. Secondly, due to the limitation of the power supply voltage of a general chip, the maximum value of the output voltage of the Hall sensor cannot be too large, so that the Hall sensor needs to compromise in two aspects of sensitivity and measurement range, namely high sensitivity and wide measurement range cannot be realized at the same time. Finally, because the Hall element is greatly influenced by temperature, a relatively complex temperature compensation circuit is generally designed, when the temperature changes, the temperature is measured through a temperature sensor, then a compensation value is calculated according to the temperature change and through a certain algorithm, and the Hall output voltage of the excitation source is compensated, so that the complexity of the Hall sensor chip is greatly increased.
Disclosure of Invention
The embodiment of the invention aims to provide a Hall sensor adopting frequency output, which changes the method for directly measuring the Hall voltage in the Hall sensor to obtain the magnetic field strength in the prior art, converts the Hall voltage into a frequency signal by utilizing the frequency response characteristic of the Hall voltage to an excitation power supply, and obtains the magnetic field strength value by measuring the frequency signal.
In order to achieve the above object, an embodiment of the present invention provides a hall sensor using frequency output, including:
the compensation circuit is used for providing a reference voltage irrelevant to an external magnetic field; the change rule of the reference voltage along with the temperature is the same as the change rule of the Hall voltage output by the measuring circuit along with the temperature; the reference voltage is determined by the frequency of an excitation source in the compensation circuit and the current of the induction coil;
the measuring circuit is used for generating Hall voltage according to the externally applied magnetic field and enabling the Hall voltage to be reduced along with the increase of the excitation source frequency of the measuring circuit; the frequency of the excitation source of the measuring circuit is measured, and the magnitude of the external magnetic field is determined according to the frequency of the excitation source of the measuring circuit;
the subtracter is used for calculating the voltage difference value between the reference voltage and the Hall voltage and feeding back the voltage difference value to the excitation source of the measuring circuit;
the measuring circuit excitation source is used for providing driving current for the measuring circuit; and the negative feedback is performed according to the voltage difference value, so that the frequency of the excitation source of the measuring circuit is adjusted, and the Hall voltage is changed, and the value of the Hall voltage is always equal to the reference voltage.
Optionally, the measurement circuit includes: a first hall element H1, a first capacitor C1, a first differential amplifier, and a first peak extraction circuit;
the excitation sources are connected in parallel to two driving ends of the first Hall element H1;
the first capacitor C1 is connected in parallel between the two Hall electrodes of the first Hall element H1; the two Hall electrodes of the first Hall element H1 are respectively connected to the two input ends of the first differential amplifier;
the output of the first differential amplifier is connected to the input of the first peak extraction circuit, and the output of the first peak extraction circuit is connected to the second input of the subtractor.
Optionally, the compensation circuit includes: the constant-frequency alternating current signal source, a second Hall element H2, a second capacitor C2, a first signal processing circuit, a third Hall element H3, a third capacitor C3, a second signal processing circuit, a second differential amplifier and a second peak extraction circuit;
the second Hall element H2 is provided with a first induction coil; a second induction coil is arranged on the third Hall element H3; the currents in the first induction coil and the second induction coil are equal in magnitude and opposite in direction;
the fixed-frequency alternating current signal source is connected in parallel to two driving ends of the second Hall element H2 and two driving ends of the third Hall element H3;
the second capacitor C2 is connected in parallel between the two Hall electrodes of the second Hall element H2; the two Hall electrodes of the second Hall element H2 are connected to the input end of a first signal processing circuit, and the output end of the first signal processing circuit is connected to the first input end of a second differential amplifier;
the third capacitor C3 is connected in parallel between the two Hall electrodes of the third Hall element H3; the two Hall electrodes of the third Hall element H3 are connected to the input end of a second signal processing circuit, and the output end of the second signal processing circuit is connected to the second input end of the second differential amplifier;
the output end of the second differential amplifier is connected to the input end of the second peak value extraction circuit, and the output end of the second peak value extraction circuit is connected to the first input end of the subtracter.
Optionally, the measurement circuit excitation source is a frequency-adjustable alternating current excitation source.
Optionally, the amplitude of the frequency-adjustable alternating current excitation source is the same as the amplitude of the fixed frequency alternating current signal source.
Optionally, the first hall element H1, the second hall element H2, and the third hall element H3 are hall elements with the same material and shape and size.
Optionally, the first capacitor C1, the second capacitor C2 and the third capacitor C3 have the same capacitance.
Optionally, the expression of the reference voltage amplitude provided by the compensation circuit is:
wherein V is R Is the reference voltage amplitude; μ is carrier mobility; w is the width of the Hall element; l is the length of the Hall element; v is the amplitude of the excitation signal; b (B) con A magnetic field generated for the induction coil; r is the output resistance of the Hall element, C is the capacitance between the Hall element electrodes; f (f) R Is the frequency of the fixed-frequency alternating current signal source.
Optionally, the hall voltage amplitude expression generated by the measurement circuit is:
wherein V is H The Hall voltage amplitude generated by the measuring circuit is measured; μ is carrier mobility; w is the width of the Hall element; l is the length of the Hall element; v is the amplitude of the excitation signal; b is an externally applied magnetic field; r is the output resistance of the Hall element, C is the capacitance between the Hall element electrodes; f is the frequency of the voltage-controlled variable-frequency alternating-current signal source.
Optionally, the magnitude of the externally applied magnetic field is determined according to the frequency of the excitation source, and the following formula is satisfied:
when RCf and RCf R When the ratio is far greater than 1, (6) can be simplified as:
wherein B is an externally applied magnetic field; b (B) con A magnetic field generated for the induction coil; f is the frequency of the voltage-controlled variable-frequency alternating-current signal source; f (f) R Is the frequency of the fixed-frequency alternating current signal source.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
the application provides a hall sensor adopting frequency output, utilizes the frequency response characteristic of hall voltage to excitation power supply, changes hall voltage into frequency signal, obtains the intensity value of magnetic field through the measurement to frequency signal, and measuring range does not receive the influence of power supply voltage upper limit, can also improve magnetic field measurement's sensitivity under the prerequisite of guaranteeing maximum measuring range.
Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain, without limitation, the embodiments of the invention. In the drawings:
fig. 1 schematically shows a schematic structural diagram of a hall sensor employing frequency output according to an embodiment of the present application.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it should be understood that the specific implementations described herein are only for illustrating and explaining the embodiments of the present application, and are not intended to limit the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.
It should be noted that, if there is a description of "first", "second", etc. in the embodiments of the present application, the description of "first", "second", etc. is only for descriptive purposes, and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present application.
The working mode of the Hall sensor in the prior art is that a voltage or current excitation is applied to the Hall sensor, so that carriers in the Hall element flow along a certain direction, when a magnetic field vertical to the surface of the Hall element is applied, the carriers flowing along a certain direction deflect under the action of Lorentz force, when the balance state is reached, a pressure difference which is in direct proportion to the magnetic field intensity is generated between two side surfaces of the Hall element, the pressure difference becomes a Hall voltage, and the value of the magnetic field intensity can be obtained through measuring the Hall voltage. In the prior art, the Hall voltage is directly measured to calculate the value of the external magnetic field, and the Hall voltage is amplified, filtered and offset and temperature drift compensated only because the Hall voltage is generally smaller, but the Hall voltage is directly measured essentially, and the Hall voltage is output as a voltage signal whether in digital output or analog output.
The invention changes the method for directly measuring the Hall voltage in the Hall sensor to obtain the magnetic field intensity in the traditional technology, converts the Hall voltage into a frequency signal by utilizing the frequency response characteristic of the Hall voltage to the excitation power supply, and obtains the magnetic field intensity value by measuring the frequency signal.
The present embodiment includes a hall element, which may be any type of hall element. The frequency-adjustable excitation source comprises an excitation source which can be a sine wave, a square wave or other waveforms, and can be a voltage source or a current source. And a capacitor connected between the two hall electrodes of the hall device. Under the condition of a certain magnetic field, the Hall output voltage is also a voltage signal with the same frequency as the excitation source under the action of the excitation source, and the maximum value of the output Hall voltage is changed along with the change of the frequency due to the charge and discharge action of the capacitor, wherein the specific relation is determined by the following formula:
wherein V is H0 The Hall voltage is output when the frequency is zero; v (V) Hf The maximum value of the Hall voltage (namely the amplitude of the Hall output voltage) when the frequency is f; r is the output resistance of the Hall element, C is the capacitance between the Hall electrodes of the Hall element; v (V) H0 The expression of (a constant voltage source supply) is as follows:
wherein μ is carrier mobility; w is the width of the Hall element; l is the length of the Hall element; v is the amplitude of the excitation signal; b is an externally applied magnetic field.
As can be seen from equations (1) to (2), the increase in frequency f decreases the magnitude of the hall output voltage without changing the applied magnetic field B and the excitation signal magnitude V. From another point of view, if we fix the amplitude of the hall output voltage to a value independent of the applied magnetic field by adjusting the frequency of the excitation signal, the frequency of the excitation source is directly proportional to the applied magnetic field, as follows:
wherein μ is carrier mobility; w is the width of the Hall element; v is the amplitude of the excitation signal; l is the length of the Hall element; v (V) Hcon Is a voltage value irrelevant to an external magnetic field; r is the output resistance of the Hall element; c is the capacitance between the Hall electrodes of the Hall element; b is an externally applied magnetic field. The intensity of the external magnetic field can be obtained through the collection of the frequency of the excitation signal.
From the above equation, it can be seen that not only can the magnetic field value be obtained by measuring the frequency, but also the sensitivity of the measurement can be changed by adjusting various parameters, wherein it is most convenient to change the capacitance values C and R. The output maximum value is not limited by the power supply voltage due to the collected frequency signal, so that the measuring range of the Hall sensor can be greatly expanded. At the same time, by properly adjusting the values of R and C, a relatively high sensitivity can also be obtained.
Regarding the temperature compensation method, the parameters most significantly affected by temperature in the above formula are the carrier mobility μ and the output resistance R value of the hall element, since in the invention are the maximum value of the hall voltage and V by output Hcon Directly comparing, the frequency value of the exciting power supply is changed according to the difference value, so that V can be obtained by Hcon The influence of temperature on the Hall voltage is directly compensated along with the temperature change.
Fig. 1 schematically shows a schematic structural diagram of a hall sensor employing frequency output according to an embodiment of the present application. As shown in fig. 1, in an embodiment of the present application, there is provided a hall sensor employing frequency output, including:
the compensation circuit is used for providing a reference voltage irrelevant to an external magnetic field; the change rule of the reference voltage along with the temperature is the same as the change rule of the Hall voltage output by the measuring circuit along with the temperature; the reference voltage is determined by the frequency of the excitation source in the compensation circuit and the magnitude of the induction coil current.
Specifically, as shown in fig. 1, the compensation circuit includes: the constant-frequency alternating current signal source, a second Hall element H2, a second capacitor C2, a first signal processing circuit, a third Hall element H3, a third capacitor C3, a second signal processing circuit, a second differential amplifier and a second peak extraction circuit; the second Hall element H2 is provided with a first induction coil; a second induction coil is arranged on the third Hall element H3; the currents in the first induction coil and the second induction coil are equal in magnitude and opposite in direction; the fixed-frequency alternating current signal source is connected in parallel to two driving ends of the second Hall element H2 and two driving ends of the third Hall element H3; the second capacitor C2 is connected in parallel between the two Hall electrodes of the second Hall element H2; the two Hall electrodes of the second Hall element H2 are connected to the input end of a first signal processing circuit, and the output end of the first signal processing circuit is connected to the first input end of a second differential amplifier; the third capacitor C3 is connected in parallel between the two Hall electrodes of the third Hall element H3; the two Hall electrodes of the third Hall element H3 are connected to the input end of a second signal processing circuit, and the output end of the second signal processing circuit is connected to the second input end of the second differential amplifier; the output end of the second differential amplifier is connected to the input end of the second peak value extraction circuit, and the output end of the second peak value extraction circuit is connected to the first input end of the subtracter. The fixed frequency alternating current signal source is an excitation source in the compensation circuit.
Specifically, the compensation circuit is responsible for generating a reference voltage independent of the applied magnetic field, and the reference voltage amplitude expression is:
wherein V is R Is the reference voltage amplitude; μ is carrier mobility; w is the width of the Hall element; l is the length of the Hall element; v is the amplitude of the excitation signal, namely the amplitude of a fixed-frequency alternating current signal source in the compensation circuit; b (B) con A magnetic field generated for the induction coil; r is the output resistance of the Hall element, C is the capacitance between the Hall element electrodes; f (f) R Is the frequency of the fixed-frequency alternating current signal source.
The measuring circuit is used for generating Hall voltage according to the externally applied magnetic field and enabling the Hall voltage to be reduced along with the increase of the excitation source frequency of the measuring circuit; and the frequency measuring circuit is used for measuring the frequency of the measuring circuit excitation source and determining the magnitude of the external magnetic field according to the frequency of the measuring circuit excitation source.
Specifically, as shown in fig. 1, the measurement circuit includes: a first hall element H1, a first capacitor C1, a first differential amplifier, and a first peak extraction circuit; the excitation sources are connected in parallel to two driving ends of the first Hall element H1; the first capacitor C1 is connected in parallel between the two Hall electrodes of the first Hall element H1; the two Hall electrodes of the first Hall element H1 are respectively connected to the two input ends of the first differential amplifier; the output of the first differential amplifier is connected to the input of the first peak extraction circuit, and the output of the first peak extraction circuit is connected to the second input of the subtractor.
Specifically, the measuring circuit excitation source is a frequency-adjustable alternating current excitation source. The embodiment adopts a voltage-controlled variable-frequency alternating-current signal source as an excitation source of a measuring circuit.
Specifically, the hall voltage expression generated by the measurement circuit is as follows:
wherein V is H The Hall voltage amplitude generated by the measuring circuit is measured; μ is carrier mobility; w is the width of the Hall element; l is the length of the Hall element; v is the amplitude of the excitation signal, namely the amplitude of the frequency-adjustable alternating current excitation source in the measuring circuit; b is an externally applied magnetic field; r is the output resistance of the Hall element, C is the capacitance between the Hall element electrodes; f is the frequency of the voltage-controlled variable-frequency alternating-current signal source.
In this embodiment, the amplitude of the fixed frequency ac signal source in the compensation circuit is the same as the amplitude of the frequency-adjustable ac excitation source in the measurement circuit.
Specifically, the first hall element H1, the second hall element H2, and the third hall element H3 are hall elements with the same material and shape and size; the first capacitor C1, the second capacitor C2 and the third capacitor C3 have the same capacitance.
The subtracter is used for calculating the voltage difference value between the reference voltage and the Hall voltage and feeding back the voltage difference value to the excitation source of the measuring circuit.
The measuring circuit excitation source is used for providing driving current for the measuring circuit; and the negative feedback is performed according to the voltage difference value, so that the frequency of the excitation source of the measuring circuit is adjusted, and the Hall voltage is changed, and the value of the Hall voltage is always equal to the reference voltage.
Specifically, the excitation source of the measuring circuit is an excitation source capable of performing frequency adjustment, and the excitation source can be a sine wave, a square wave or other waveforms, and can be a voltage source or a current source. The excitation source in this embodiment is a voltage-controlled variable-frequency ac signal source.
Specifically, let V H And V R Subtracting and feeding back to voltage-controlled variable frequency AC signal source, adopting negative feedback to make V H And V R Always equal, a simple relationship of f and the applied magnetic field B is obtained as follows:
when RCf and RCf R When the ratio is far greater than 1, (6) can be simplified as:
wherein B is an externally applied magnetic field; b (B) con A magnetic field generated for the induction coil; f is the frequency of the voltage-controlled variable-frequency alternating-current signal source; f (f) R Is the frequency of the fixed-frequency alternating current signal source.
In the embodiment, the frequency-adjustable alternating current excitation source is adopted to excite the Hall sensor, and the amplitude of the Hall output voltage changes along with the change of frequency by utilizing an RC circuit formed by the capacitance (which can be an additional parasitic capacitance caused by the capacitance effect of the Hall element) between two Hall electrodes of the Hall element and the output resistance of the Hall element. The amplitude of the Hall output voltage which changes along with the change of the frequency is compared with a reference voltage which is irrelevant to an external magnetic field, so as to generate negative feedback, the frequency of the adjustable AC excitation source is adjusted by the feedback quantity, and the amplitude of the Hall voltage is always equal to the reference voltage as a result of the adjustment. Under the condition that the Hall voltage and the reference voltage are always equal, the frequency of the excitation source is measured, and the frequency and the external magnetic field are in a linear relation, so that the external magnetic field intensity value can be obtained through measuring the frequency. The temperature compensation circuit generates an output voltage which is irrelevant to an external magnetic field as a reference voltage in a differential output mode of two Hall sensors with induction coils. The excitation source of the temperature compensation circuit is selected to be an alternating current excitation source with a certain frequency, and the two quantities of the Hall output resistor R and the capacitance C between the Hall electrodes in the generated reference voltage expression are compared with the Hall output voltage in the measuring circuit, so that the temperature drift of the sensor caused by the change of R and C along with the temperature change can be eliminated.
In the embodiment, the magnetic field is measured by adopting a frequency measuring mode, the frequency change range is large, and the measuring range is not influenced by the upper limit of the power supply voltage.
The embodiment adopts the measuring frequency to measure the magnetic field, so that higher sensitivity can be obtained, the sensitivity is not affected on the premise of ensuring the maximum measuring range, the sensitivity can be optimized by adjusting a plurality of parameters, and the design freedom of the device is improved.
The embodiment adopts the measuring frequency to measure the magnetic field, the frequency output is more convenient for digitalization, the A/D conversion is not needed, and the complexity and the cost of the circuit are reduced. The method is natural and compatible with a rotating current method, and can effectively eliminate the influence of the offset voltage of the Hall.
In the embodiment, the measured Hall voltage is compared with the reference voltage by adopting a frequency adjusting mode, negative feedback is carried out, and temperature compensation can be automatically realized by selecting the proper reference voltage, so that the design of a temperature compensation circuit is greatly simplified, and the temperature drift of a sensor is reduced.
The embodiment adopts the high-frequency excitation source to provide excitation for the Hall sensor, so that 1/f noise can be effectively eliminated, and the precision of the Hall sensor is improved.
The above scheme is only one embodiment of the present invention, and the form of the compensation circuit may be other possible schemes, not limited to the above scheme.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.

Claims (10)

1. A hall sensor employing frequency output, comprising:
the compensation circuit is used for providing a reference voltage irrelevant to an external magnetic field; the change rule of the reference voltage along with the temperature is the same as the change rule of the Hall voltage output by the measuring circuit along with the temperature; the reference voltage is determined by the frequency of an excitation source in the compensation circuit and the current of the induction coil;
the measuring circuit is used for generating Hall voltage according to the externally applied magnetic field and enabling the Hall voltage to be reduced along with the increase of the excitation source frequency of the measuring circuit; the frequency of the excitation source of the measuring circuit is measured, and the magnitude of the external magnetic field is determined according to the frequency of the excitation source of the measuring circuit;
the subtracter is used for calculating the voltage difference value between the reference voltage and the Hall voltage and feeding back the voltage difference value to the excitation source of the measuring circuit;
the measuring circuit excitation source is used for providing driving current for the measuring circuit; and the negative feedback is performed according to the voltage difference value, so that the frequency of the excitation source of the measuring circuit is adjusted, and the Hall voltage is changed, and the value of the Hall voltage is always equal to the reference voltage.
2. The hall sensor of claim 1, wherein the measurement circuit comprises: a first hall element H1, a first capacitor C1, a first differential amplifier, and a first peak extraction circuit;
the excitation sources are connected in parallel to two driving ends of the first Hall element H1;
the first capacitor C1 is connected in parallel between the two Hall electrodes of the first Hall element H1; the two Hall electrodes of the first Hall element H1 are respectively connected to the two input ends of the first differential amplifier;
the output of the first differential amplifier is connected to the input of the first peak extraction circuit, and the output of the first peak extraction circuit is connected to the second input of the subtractor.
3. The hall sensor of claim 2, wherein the compensation circuit comprises: the constant-frequency alternating current signal source, a second Hall element H2, a second capacitor C2, a first signal processing circuit, a third Hall element H3, a third capacitor C3, a second signal processing circuit, a second differential amplifier and a second peak extraction circuit;
the second Hall element H2 is provided with a first induction coil; a second induction coil is arranged on the third Hall element H3; the currents in the first induction coil and the second induction coil are equal in magnitude and opposite in direction;
the fixed-frequency alternating current signal source is connected in parallel to two driving ends of the second Hall element H2 and two driving ends of the third Hall element H3;
the second capacitor C2 is connected in parallel between the two Hall electrodes of the second Hall element H2; the two Hall electrodes of the second Hall element H2 are connected to the input end of a first signal processing circuit, and the output end of the first signal processing circuit is connected to the first input end of a second differential amplifier;
the third capacitor C3 is connected in parallel between the two Hall electrodes of the third Hall element H3; the two Hall electrodes of the third Hall element H3 are connected to the input end of a second signal processing circuit, and the output end of the second signal processing circuit is connected to the second input end of the second differential amplifier;
the output end of the second differential amplifier is connected to the input end of the second peak value extraction circuit, and the output end of the second peak value extraction circuit is connected to the first input end of the subtracter.
4. A hall sensor according to claim 3, wherein the measurement circuit excitation source is a frequency modulated ac excitation source.
5. The hall sensor according to claim 4 wherein the amplitude of the frequency modulated ac excitation source is the same as the amplitude of the fixed frequency ac signal source.
6. The hall sensor according to claim 3, wherein the first hall element H1, the second hall element H2 and the third hall element H3 are hall elements having the same material and shape and size.
7. The hall sensor according to claim 6, wherein the first capacitor C1, the second capacitor C2 and the third capacitor C3 have the same capacitance.
8. The hall sensor of claim 7 wherein the compensation circuit provides a reference voltage magnitude expressed as:
wherein V is R Is the reference voltage amplitude; μ is carrier mobility; w is the width of the Hall element; l is the length of the Hall element; v is the amplitude of the excitation signal; b (B) con A magnetic field generated for the induction coil; r is the output resistance of the Hall element, C is the capacitance between the Hall element electrodes; f (f) R Is the frequency of the fixed-frequency alternating current signal source.
9. The hall sensor of claim 8 wherein the measurement circuit produces a hall voltage amplitude expression of:
wherein V is H The Hall voltage amplitude generated by the measuring circuit is measured; μ is carrier mobility; w is the width of the Hall element; l is the length of the Hall element; v is the amplitude of the excitation signal; b is an externally applied magnetic field; r is the output resistance of the Hall element, C is the capacitance between the Hall element electrodes; f is the frequency of the voltage-controlled variable-frequency alternating-current signal source.
10. The hall sensor according to claim 9, wherein the magnitude of the externally applied magnetic field is determined according to the frequency of the excitation source, and the following formula is satisfied:
when RCf and RCf R When the ratio is far greater than 1, (6) can be simplified as:
wherein B is an externally applied magnetic field; b (B) con A magnetic field generated for the induction coil; f is the frequency of the voltage-controlled variable-frequency alternating-current signal source; f (f) R Is the frequency of the fixed-frequency alternating current signal source.
CN202311302725.1A 2023-10-09 2023-10-09 Hall sensor using frequency output Pending CN117420484A (en)

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Application Number Priority Date Filing Date Title
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CN117420484A true CN117420484A (en) 2024-01-19

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