TWI658283B - Magnetic sensing circuit - Google Patents

Abstract

The invention provides a magnetic sensing circuit which does not output spike-shaped voltage errors to a signal processing circuit. The magnetic sensing circuit is characterized by being configured to output an output signal to a signal processing circuit via a plurality of Hall elements driven by a first switching circuit and a second switching circuit controlled by a second control circuit. The circuit controls such that the timings at which the spikes occur in the output signals of the plurality of Hall elements are different, and the second switch circuit selects and outputs the output signals during the time when the spikes are not generated.

Description

Magnetic sensing circuit

The present invention relates to a magnetic sensor circuit. More specifically, the present invention relates to a magnetic sensor that can reduce spikes that occur when the terminals of a Hall element are switched. Circuit.

The magnetic sensing circuit includes a Hall element and a signal processing circuit, but an offset voltage is generated in the Hall element or the signal processing circuit, and the output is not zero even in a zero magnetic field state where no magnetic field is applied The voltage.

Examples of the cause of the offset voltage of the Hall element include manufacturing variations and stresses, and the influence of a peripheral magnetic field. For the problem of the offset voltage of the Hall element, a driving method called a spinning current method is generally used.

When each terminal is placed at four corners in a square-shaped Hall element, when a driving current flows through a counter terminal of 0 degrees and when a driving current flows through a counter terminal of 90 degrees When a magnetic field is applied, the offset voltage is reversed and the voltage corresponding to the magnetic field is in-phase, so they are added together and a meaningful signal with reduced offset error is derived for signal processing.

FIG. 17 is a circuit diagram showing a conventional double-rotation magnetic sensing circuit.

The Hall element 1 has four terminals (nodes N1 to N4). The first switching circuit 3 controlled by the control circuit 5 is connected to a power supply voltage and a ground voltage. The signal processing circuit 2 is connected to the Hall element 1 via a second switching circuit 4 controlled by a second control circuit 6.

FIG. 18 shows a time chart of a conventional magnetic sensor circuit with two rotations. In the figure, the control signal is switched on when the control signal is at a high level, and is switched off when the control signal is at a low level. A rotation period is divided into a period Φ1 and a period Φ2.

During the period Φ1, the control signals SS1V, SS1G, SS1P, and SS1M are at a high level. Therefore, during the period Φ1, the constant current source 15 is connected to the node N2, the ground voltage is connected to the node N4, the node N1 is connected to the positive-phase input terminal INP, and the node N3 is connected to the negative-phase input terminal INM.

During the period Φ2, the control signals SS2V, SS2G, SS2P, and SS2M are at a high level. During the period Φ2, the constant current source 7 is connected to the node N3, the ground voltage is connected to the node N1, the node N2 is connected to the positive-phase input terminal INP, and the node N4 is connected to the negative-phase input terminal INM.

With this connection, the differential signal (INP-INM) becomes the signal voltage Vsig corresponding to the magnetism during the periods Φ1 and Φ2. Moreover, in the period of Φ1, a negative spike-shaped voltage is generated immediately after switching, and in the period of Φ2, a positive spike-shaped voltage is generated.

As a countermeasure against the spike-shaped voltage error, for example, the methods of Patent Literature 1 and Patent Literature 2 are known. In Patent Document 1, a phenomenon in which a spike-shaped voltage error generated when the clockwise rotation and the counterclockwise rotation are switched is a positive and negative sign is added and averaged to reduce the error. On the other hand, in Patent Document 2, a device having a sample-and-hold circuit for one Hall element is provided. The discrete signal processing circuit is the premise. After the rotation switching, the Hall element and the signal processing circuit are separated immediately. The signal processing circuit performs signal processing based on the signal held by the sample-and-hold circuit. Therefore, the signal transmission during the spike-like error after switching is Masking to reduce the impact of spike-like errors on signal processing accuracy.

Prior art literature Patent literature

Patent Document 1: US Patent No. 6,925,572

Patent Document 2: US Patent No. 5,621,319

In the method described in Patent Document 1, a method of canceling a positive spike-like error and a negative spike-like error is used. However, the positive spike-like error and the negative spike-like error are caused by manufacturing variations or element structures. It is not completely consistent, thus becoming a factor of residual error.

The method of Patent Document 2 is based on the premise that discrete-time signal processing is provided with a sample-and-hold circuit. Therefore, there is a masked period in which the output signal of the Hall element is not transmitted to the signal processing circuit, so it is not suitable for continuous-time signals. deal with.

The present invention has been made in view of the above problems, and an object thereof is to provide a magnetic sensing circuit having a circuit for reducing a spike-shaped voltage error, which is suitable for a continuous-time signal processing circuit or a Discrete time Signal processing circuits are suitable.

As a technical means for solving the problem, the invention disclosed in the present invention is roughly constituted as follows.

The magnetic sensing circuit includes: a plurality of Hall elements including a plurality of terminals; a first switch circuit disposed between the plurality of terminals of the plurality of Hall elements and a power terminal and a ground terminal, The first element switches to supply a driving current; the second switching circuit is connected to a plurality of terminals of the plurality of Hall elements, and selects and outputs the output signals of the plurality of Hall elements; the first control circuit is adapted to the first switch The circuit outputs a first control signal; the second control circuit outputs a second control signal to the second switch circuit; and the signal processing circuit receives the output signal output by the second switch circuit and performs signal processing, A first control circuit controls the plurality of Hall elements so that the time when a spike occurs in the output signals of the plurality of Hall elements is different, and the second control circuit controls the second switching circuit so as not to select all The output signals of the fixed period in which the spikes are generated among the output signals of the plurality of Hall elements, and the output of the fixed periods in which the spikes are not generated among the output signals of the plurality of Hall elements are selected. No., the output of the second switch circuit, the output signal during the selection of all one or more elements of any of the plurality of Hall.

According to the present invention, the residual error caused when the spike-shaped voltage error after switching the rotation of the Hall element is directly canceled by using positive and negative spikes is not generated. Moreover, by using multiple Hall elements to select the output spike voltage disappears The voltage value after a fixed time can greatly reduce the spike-like voltage error caused by the Hall element capacitance. In addition, since the signal during the period when the spike-like error disappears is always used, the rotation frequency can be increased in speed.

Furthermore, according to the present invention, each Hall element avoids a spike-like error period, thereby enabling a processing speed of a signal processing circuit (for example, an analog / digital converter) to be increased. Moreover, the output signal voltage of the Hall element can be continuously transmitted to the signal processing circuit, which is suitable for continuous signal processing. In addition, when the signal processing circuit is used for multisampling in the first phase and the second phase, the Hall output signal can be transmitted without interruption. In addition, in the case of discrete-time signal processing using a measurement amplifier, unnecessary charge and discharge are not generated, so the current consumption of the measurement amplifier can be reduced.

1,1a, 1A, 1b, 1B, 1C, 1D‧‧‧Hall element

2, 16, 36‧‧‧ signal processing circuit

3, 13, 33, 103, 163‧‧‧ the first switch circuit

4,14,34,74,104‧‧‧Second switch circuit

5, 11, 31‧‧‧ first control circuit

6, 12, 32, 72‧‧‧ second control circuit

7, 15, 15A, 15B, 15C, 15D‧‧‧ constant current sources

INM, INMA, INMB, INMC, INMD ‧‧‧ negative phase input terminal

INP, INPA, INPB, INPC, INPD‧‧‧ Non-inverting input terminals

D1, D2, D1A, D1B, D1C, D4C, N1 ~ N4, N1A ~ N4A, N1B ~ N4B, N1C ~ N4C, N1D ~ N4D‧‧‧ nodes

SS1G, SS1M, SS1P, SS1V, SS2G, SS2M, SS2P, SS2V, Control signal

Vsig‧‧‧Signal voltage

Φ1, Φ2, Φ3, Φ4‧‧‧

Φ11, Φ12, Φ13, Φ14, Φ21, Φ22, Φ23, Φ24, Φ31, Φ32, Φ33, Φ34, Φ41, Φ42, Φ43, Φ44‧‧‧

FIG. 1 is a circuit diagram of a magnetic sensing circuit according to the first embodiment.

FIG. 2 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the first embodiment.

3 is a circuit diagram of a magnetic sensing circuit according to a second embodiment.

4 is a circuit diagram showing an example of a first switching circuit of a magnetic sensing circuit according to a second embodiment.

FIG. 5 is a circuit diagram showing an example of a second switching circuit of the magnetic sensing circuit according to the second embodiment.

FIG. 6 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the second embodiment.

FIG. 7 is a circuit diagram of a magnetic sensing circuit according to a third embodiment.

FIG. 8 is a circuit diagram showing an example of a second switching circuit of the magnetic sensing circuit according to the third embodiment.

FIG. 9 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the third embodiment.

FIG. 10 is a circuit diagram of a magnetic sensing circuit according to a fourth embodiment.

11 is a circuit diagram showing an example of a first switching circuit of a magnetic sensing circuit according to a fourth embodiment.

FIG. 12 is a circuit diagram showing an example of a second switching circuit of the magnetic sensing circuit according to the fourth embodiment.

FIG. 13 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the fourth embodiment.

FIG. 14 is a circuit diagram showing an example of a configuration of a Hall element of the magnetic sensing circuit of the present invention.

FIG. 15 is a circuit diagram showing an example of a configuration of a Hall element of the magnetic sensing circuit of the present invention.

FIG. 16 is a circuit diagram showing an example of a configuration of a driving circuit of the magnetic sensing circuit of the present invention.

FIG. 17 is a circuit diagram showing a conventional double-rotation magnetic sensing circuit.

FIG. 18 is a time chart of a conventional double-rotation magnetic sensing circuit.

Hereinafter, embodiments of the magnetic sensing circuit of the present invention will be described with reference to a circuit diagram.

<First Embodiment>

FIG. 1 is a circuit diagram of a magnetic sensing circuit according to the first embodiment.

The magnetic sensing circuit includes a first Hall element 1A, a second Hall element 1B, a first switching circuit 13, a second switching circuit 14, a first control circuit 11, a second control circuit 12, a constant current source 15, and signal processing. Circuit 16. The signal processing circuit 16 corresponds to a chopping modulation / demodulation circuit or an addition or filter processing circuit, an analog / digital converter, a comparator (magnetic switch circuit), and the like.

The first Hall element 1A has four terminals, and a node of each terminal is set to N1A to N4A. The second Hall element 1B has four terminals, and the nodes of each terminal are set to N1B to N4B. The signal processing circuit 16 includes a positive-phase input terminal INP and a negative-phase input terminal INM.

The first Hall element 1A is connected to the power supply voltage and the ground voltage via a first switching circuit 13 controlled by a first control circuit 11, and the second Hall element 1B is connected to a power supply voltage and a ground voltage via a second switching circuit 14 controlled by a second control circuit 12. It is connected to the signal processing circuit 16.

Each switch of the first switch circuit 13 receives the control signals SS1VA, SS1VB, SS2VA, SS2VB, SS1GA, SS1GB, SS2GA, and SS2GB, respectively. To control. Each switch of the second switch circuit 14 is controlled by control signals SS1PA, SS1PB, SS2PA, SS2PB, SS1MA, SS1MB, SS2MA, and SS2MB.

Next, an operation of the magnetic sensing circuit according to the first embodiment will be described. FIG. 2 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the first embodiment.

A rotation period is divided into a period Φ1 and a period Φ2. Furthermore, the period Φ1 is divided into a sub period Φ11 and a sub period Φ12, and the period Φ2 is divided into a sub period Φ21 and a sub period Φ22. Control signals SS1VA and SS1GA are at high level during period Φ1, control signals SS2VA and SS2GA are at high level during period Φ2, control signals SS1VB and SS1GB are at high level during period Φ12 and period Φ21, and control signals SS2VB and SS2GB are during period Φ22 and period Φ11 High level. In addition, the control signals SS1PA and SS1MA are at a high level during period Φ12, the control signals SS2PA and SS2MA are at a high level during period Φ22, the control signals SS1PB and SS1MB are at a high level during period Φ21, and the control signals SS2PB and SS2MB are at a high level during period Φ11.

Therefore, during the period Φ11, the constant current source 15 is connected to the node N2A, the ground voltage is connected to the node N4A, the constant current source 15 is connected to the node N3B, and the ground voltage is connected to the node N1B. The two Hall elements are driven. The Hall element node N2B of the Hall element 1B is connected to the non-inverted input terminal INP, and the Hall element node N4B of the Hall element 1B is connected to the negative-phase input terminal INM. During this period, the rotation switching timing of the Hall element 1B is at the beginning of the period Φ22, so no spike-shaped voltage error is generated in the differential output signal (INP-INM). The operation principle of the period Φ12, the period Φ21, and the period Φ22 is the same. Any one of the Hall element 1A and the Hall element 1B A differential signal in a period in which no spike-like voltage error occurs is selected and output as an input signal (INP-INM) of the signal processing circuit 16.

Therefore, in the case of the magnetic sensing circuit of the first embodiment, there is an advantage that a spike-like error does not occur at the input of the signal processing circuit 16. In addition, in this embodiment, by selecting the voltage during the period in which the spike-shaped error is shielded and stabilized, the rotation frequency and the signal processing conversion rate of the signal processing circuit 16 (for example, analog / digital converter) can be further improved. Sampling rate). Therefore, the Signal Noise Ratio (S / N) of the magnetic sensing circuit can be kept fixed.

Moreover, the output signal voltage of the Hall element can be continuously transmitted to the signal processing circuit 16, which is suitable for continuous signal processing.

Further, in the case of discrete-time signal processing using a measurement amplifier, there is an effect that an unnecessary charge and discharge does not occur and the consumption current of the measurement amplifier does not increase.

<Second Embodiment>

3 is a circuit diagram of a magnetic sensing circuit according to a second embodiment.

The magnetic sensing circuit of this embodiment includes a first Hall element 1A, a second Hall element 1B, a third Hall element 1C, a fourth Hall element 1D, a first switching circuit 33, a second switching circuit 34, a first A control circuit 31, a second control circuit 32, and a signal processing circuit 36. The node D1 is connected to the constant current source 15, and the node D2 is connected to a ground terminal.

The third Hall element 1C and the fourth Hall element 1D are the same as the first Hall element 1A and the second Hall element 1B similarly have four terminals, and the nodes of each terminal are set to N1C to N4C and N1D to N4D. The signal processing circuit 36 includes positive-phase input terminals INPA, INPB, INPC, and INPD and negative-phase input terminals INMA, INMB, INMC, and INMD.

For the Hall element, a third Hall element 1C and a fourth Hall element 1D are added to the magnetic sensing circuit of the first embodiment, and are also connected between the first switch circuit 33 and the second switch circuit 34.

The first switch circuit 33 is similarly provided with switches corresponding to the four Hall elements. FIG. 4 is a circuit diagram showing an example of the first switching circuit 33. The input terminals, output terminals, and switches are connected and controlled in a relationship as shown in the figure.

The second switching circuit 34 includes eight output terminals corresponding to the respective input terminals of the signal processing circuit 36. FIG. 5 is a circuit diagram showing an example of the second switching circuit 34. The input terminals, output terminals, and switches are connected and controlled in a relationship as shown in the figure.

There are 4 positive-phase input terminals (INPA, INPB, INPC, INPD) and negative-phase input terminals (INMA, INMB, INMC, INMD) respectively. It is assumed that the signals of these terminals are added by the addition circuit (not (Shown) after conversion to voltage level or current level, add signal processing.

Next, an operation of the magnetic sensing circuit according to the second embodiment will be described. FIG. 6 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the second embodiment.

A rotation period is divided into a period Φ1, a period Φ2, a period Φ3, and a period Φ4. Moreover, the period Φ1 is divided into a sub period Φ11, a sub period Φ12, and a sub period Φ13. And sub-period Φ14, period Φ2 is divided into sub-period Φ21, sub-period Φ22, sub-period Φ23 and sub-period Φ24, and period Φ3 is divided into sub-period Φ31, sub-period Φ32, sub-period Φ33 and sub-period Φ34, and period Φ4 is It is divided into sub-period Φ41, sub-period Φ42, sub-period Φ43, and sub-period Φ44. The control signals SS1VA and SS1GA are at the high level during the period Φ1, the control signals SS2VA and SS2GA are at the high level during the period Φ2, the control signals SS3VA and SS3GA are at the high level during the period Φ3, and the control signals SS4VA and SS4GA are at the high level during the period Φ4. These signals It becomes a control signal for driving the Hall element 1A. The driving signals of the other Hall elements 1B, 1C, and 1D also have four phases. However, as shown in FIG. 6, the phases of the clocks are shifted by one sub-period.

For the control signal related to the output signal of the Hall element 1A, the control signals SS1PA and SS1MA are at a high level during the period Φ12 to Φ14, and the control signals SS2PA and SS2MA are at the high level during the period Φ22 to Φ24. The control signals SS3PA and SS3MA are at a high level. The period Φ32 ~ period Φ34 is the high level, and the control signals SS4PA and SS4MA are the high level during the period Φ42 ~ period Φ44. As shown in FIG. 6, the other Hall elements 1B, 1C, and 1D also have control signals with the same phase relationship. However, in each Hall element, the phase of the clock is shifted by one sub-period.

Therefore, in the sub-period Φ11, a spike is generated in the Hall element 1A, but three signals of the Hall elements 1B, 1C, and 1D are input to the signal processing circuit 36. In the other sub-periods, the output signals of the three Hall elements that do not generate spikes are transferred to the signal processing circuit 36 for addition.

Therefore, in the case of the magnetic sensing circuit of the present embodiment, there is an advantage that a spike-like error does not occur at the input of the signal processing circuit 36. Moreover, The output signal voltage of the element is continuously transmitted to the signal processing circuit 36, which is suitable for continuous signal processing.

<Third Embodiment>

FIG. 7 is a circuit diagram of a magnetic sensing circuit according to a third embodiment.

The magnetic sensing circuit of this embodiment includes a first Hall element 1A, a second Hall element 1B, a third Hall element 1C, a fourth Hall element 1D, a first switching circuit 33, a second switching circuit 74, a first A control circuit 31, a second control circuit 72, and a signal processing circuit 16.

The difference from the second embodiment is that the structure of the second switch circuit 74 is different from the control signal of the second control circuit 72, and the signal processing circuit 16 is set as a positive phase input terminal INP and a negative phase input terminal INM. Correct.

FIG. 8 is a circuit diagram showing an example of the second switching circuit 74. Each input terminal, each output terminal, and each switch are connected and controlled in the relationship shown in the figure.

Next, an operation of the magnetic sensing circuit according to the third embodiment will be described. FIG. 9 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the third embodiment.

The timing chart of this embodiment differs from the timing chart of the second embodiment in the control signal of the second control circuit 72. For example, for the first Hall element 1A, the control signal (SS1PA, SS1MA) is at the high level during the period Φ14, the control signal SS2PA, SS2MA is at the high level during the period Φ24, and the control signal SS3PA, SS3MA is at the high level during the period Φ24. In the period Φ44, the control signals SS4PA and SS4MA are at a high level. For the second Hall element 1B to the fourth Hall element 1D, it is also Control signals with the same phase relationship, but the phase of the clock is shifted by one sub-period between the Hall elements. Therefore, for the signal processing input (INP-INM), the signal of the second Hall element 1B is selected during Φ11, the signal of the third Hall element 1C is selected during Φ12, and the signal of the fourth Hall element 1D is selected during Φ13. The signal of the first Hall element 1A is selected during Φ14. In other sub-periods, the input signal to the signal processing circuit 16 is also determined based on the same principle.

Therefore, the magnetic sensing circuit of this embodiment has an advantage that no spike-like error is generated at the input of the signal processing circuit 16. In addition, in this embodiment, since four Hall elements are used, the period in which the spike-like error is shielded and stabilized can be divided into three sub-periods, so the spike-like voltage error due to the Hall element capacitance Becomes infinitely small like an exponential function. Therefore, the rotation frequency and the signal processing conversion rate of the signal processing circuit 16 (for example, the sampling rate of the analog / digital converter) can be further improved. Therefore, as the system of the magnetic sensing circuit, the S / N can be kept fixed, and thus the amount of loss can be avoided by increasing the clock rate. Moreover, the output signal voltage of the Hall element can be continuously transmitted to the signal processing circuit 16, which is suitable for continuous signal processing.

<Fourth Embodiment>

FIG. 10 is a circuit diagram of a magnetic sensing circuit according to a fourth embodiment.

The magnetic sensing circuit of this embodiment has the same circuit configuration as that of the second embodiment, but the circuits of the first switch circuit 103 and the second switch circuit 104 are different.

FIG. 11 is a circuit diagram showing an example of the first switching circuit 103. The input terminals, output terminals, and switches are connected in a relationship as shown in the figure and received. control. Therefore, the connection is performed in such a manner that the Hall element 1A rotates in a clockwise direction, the Hall element 1B rotates in a counterclockwise direction, the Hall element 1C rotates in a clockwise direction, and the Hall element 1D rotates in a counterclockwise direction.

FIG. 12 is a circuit diagram showing an example of the second switching circuit 104. Each input terminal, each output terminal, and each switch are connected and controlled in the relationship shown in the figure. The second switch circuit 104 also adopts a connection corresponding to the same rotation as the first switch circuit 103.

Next, an operation of the magnetic sensing circuit according to the fourth embodiment will be described. FIG. 13 is a timing chart showing a circuit operation of the magnetic sensing circuit according to the fourth embodiment.

The control signal of the timing chart of this embodiment is the same as the timing chart of the second embodiment, but the sign of the spike-shaped voltage error of the differential signal of the Hall element 1B and the Hall element 1D is negative. This is because the Hall element rotates differently.

In the magnetic sensing circuit of this embodiment, a period without a spike is selected as an output, but in an actual circuit, the time constant τ (A × exp (-T / τ) is included, where T is shielded Settling time). Therefore, for the Hall elements 1A and 1C, a slight error (A × exp (-T / τ)) actually occurs, and for the Hall elements 1B and 1D, a small error ((-1) × A × exp (-T / τ)). Therefore, the residual error amount of the signal can be further reduced by canceling the influence, thereby further reducing the error component of the signal.

In the magnetic sensing circuit of the present embodiment, since the stabilized voltage after the output spike disappears is selected, the influence caused by the difference in the waveform shape of the positive / negative spike voltage has little effect.

14 and 15 are circuit diagrams showing an example of a configuration of a Hall element of the magnetic sensing circuit of the present invention.

FIG. 14 connects the two Hall elements 1a and 1b to the terminals N1 to N4 as shown in the figure to form one Hall element 1. The Hall elements 1a and 1b are connected to one Hall element 1 when the terminals differ by 0 degrees or 90 degrees. By configuring the Hall element 1 in this manner, it is possible to suppress the influence of manufacturing variations and stress caused by the layout.

The structure of the Hall element 1 in FIG. 15 is the same.

16 is a circuit diagram showing an example of a configuration of a driving circuit that drives a Hall element of the magnetic sensing circuit of the present invention.

The driving circuit of FIG. 16 is provided with four constant current sources 15A, 15B, 15C, and 15D that drive four Hall elements 1A, 1B, 1C, and 1D. Nodes D1A, D1B, D1C, and D1D are connected to the constant current sources 15A, 15B, 15C, and 15D, respectively, and node D2 is connected to the ground terminal. In addition, the first switch circuit 163 is controlled in such a manner that the constant current source that drives the Hall element is switched at each rotation. By constituting the driving circuit in this way, it is possible to further suppress a weak signal variation generated at the driving end when the rotation is switched.

Furthermore, in the case of a magnetic sensing circuit including four Hall elements as shown in FIG. 16, four rotations are used as one cycle to switch the constant current source driving the Hall elements. By performing such rotation control, it is possible to suppress the influence of the current value deviation of each of the constant current sources 15A, 15B, 15C, and 15D.

According to the driving circuit of FIG. 16, the magnetic sensing circuit of the present invention can suppress the weak signal variation generated at the driving end when the rotation is switched. Moreover, according to the above The driving method described above can suppress the current deviation of each constant current source.

As described above, in the description of the embodiment of the present invention, the shape, terminals, and positional relationship (0 degrees, 90 degrees, 180 degrees, 270 degrees) of the Hall element are not limited to those shown in the drawings, and other shapes or terminals The number of Hall elements is also included in the scope of the invention.

In addition, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications or corrections that can be made by those skilled in the art within the scope of the present invention are included.

Claims (4)

A magnetic sensing circuit, comprising: a plurality of Hall elements including a plurality of terminals; a first switching circuit provided between the plurality of terminals of the plurality of Hall elements and a power terminal and a ground terminal To switch and supply a driving current to the plurality of Hall elements; a second switching circuit connected to the plurality of terminals of the plurality of Hall elements to select and output the output signals of the plurality of Hall elements; the first A control circuit that outputs a first control signal to the first switch circuit; a second control circuit that outputs a second control signal to the second switch circuit; and a signal processing circuit that receives an output from the second switch circuit Signals and perform signal processing, the first control circuit controls the plurality of Hall elements, so that the time when a spike occurs in the output signals of the plurality of Hall elements is different, and the second control circuit controls the A second switching circuit that does not select output signals of a fixed period in which the spikes are generated in the output signals of the plurality of Hall elements, and selects outputs of the plurality of Hall elements An output signal is not generated during the fixed number of spikes, the output of the second switch circuit, the output signal at all during one or more of the plurality of Hall elements in any selected output. The magnetic sensing circuit according to item 1 of the scope of patent application, wherein a constant current source is provided between the first switching circuit and the power terminal. The magnetic sensing circuit according to item 2 of the scope of patent application, wherein the constant current source is provided corresponding to the plurality of Hall elements, and is switched by the first switching circuit at each rotation. Connected to the plurality of Hall elements. The magnetic sensing circuit according to any one of claims 1 to 3, wherein the Hall element is a terminal that connects a plurality of Hall elements to terminals of the Hall element to become one Hall. element.