JP6438440B2 - Hall sensor and method for adjusting hall sensor - Google Patents

Description

  The present invention relates to a hall sensor and a method for adjusting the hall sensor.

Conventionally, in a hall sensor including a hall element, it is known that the temperature of the hall element is estimated by measuring the hall element resistance value, and temperature compensation of the output of the hall sensor is performed using the temperature (for example, Patent Document 1).
Japanese Patent Laid-Open No. 3-261869

  However, depending on the type of the Hall element, the relationship between the Hall element resistance value and the temperature is not uniquely determined. Therefore, it is difficult to adjust the temperature characteristics of the Hall sensor.

  In the first aspect of the present invention, the Hall element in which the Hall element resistance value changes so as to have an extreme value with respect to the temperature, the resistance measuring unit for detecting the Hall element resistance value of the Hall element, and the temperature with respect to the Hall element A temperature that compensates for the effect of temperature on the output of the Hall element based on the determination unit that determines the increase or decrease of the Hall element resistance value due to the change operation, the Hall element resistance value detected by the resistance measurement unit, and the determination result by the determination unit And a compensation unit.

  According to a second aspect of the present invention, there is provided a method for adjusting a Hall sensor comprising a Hall element that changes so that the Hall element resistance value has an extreme value with respect to temperature, wherein the Hall element resistance value of the Hall element is detected. The detection stage, the temperature change stage for changing the temperature of the Hall element, the determination stage for determining increase / decrease in the Hall element resistance value due to the temperature change, the Hall element resistance value detected by the detection stage, and the determination result by the determination stage In accordance with the present invention, there is provided a method for adjusting a Hall sensor comprising: a temperature compensation stage that compensates for an effect of temperature on the output of the Hall element.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

The outline of the composition of hall sensor 100 of a 1st embodiment is shown. An example of the relationship between temperature and sensitivity in the Hall element 10 is shown. An example of the relationship between the temperature in the Hall element 10 and the Hall element resistance value is shown. An example of composition of hall sensor 100 of a 1st embodiment is shown. The processing flow of the adjustment method of the Hall sensor 100 of 1st Embodiment is shown. An example of the signal waveform in each part of Hall sensor 100 of a 1st embodiment is shown. An example of composition of hall sensor 100 of a 2nd embodiment is shown. An example of a hold section is shown. An example of composition of hall sensor 100 of a 3rd embodiment is shown. An example of composition of hall sensor 100 of a 4th embodiment is shown. An example of composition of hall sensor 100 of a 5th embodiment is shown. An example of the signal waveform in each part of Hall sensor 100 of a 5th embodiment is shown. An example of composition of hall sensor 100 of a 6th embodiment is shown. The outline | summary of a structure of the Hall sensor 100 of 7th Embodiment is shown. An example of composition of hall sensor 100 of a 7th embodiment is shown. An example of composition of hall sensor 100 of an 8th embodiment is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

[First Embodiment]
FIG. 1 shows an outline of the configuration of the hall sensor 100 of the first embodiment. The Hall sensor 100 may be any sensor that detects a magnetic field using the Hall effect, and the type is not limited. For example, the hall sensor 100 is a magnetic sensor, a current sensor, a gauss meter, a rotation angle sensor, and a proximity sensor.

  The hall sensor 100 includes a hall element 10, a resistance measurement unit 20, a determination circuit 30, and a temperature compensation unit 40. The hall sensor 100 may further include a signal processing circuit 50 and a temperature changing unit 60. However, the Hall sensor 100 itself does not include the signal processing circuit 50 and the temperature changing unit 60, and the signal processing circuit 50 and the temperature changing unit 60 may be configured as external components. The signal processing circuit 50 is a signal processing unit that outputs the output signal of the Hall element 10 to the output terminal OUT. The temperature change unit 60 performs a temperature change operation on the Hall element 10. The temperature changing unit 60 temporarily increases or decreases the temperature of the Hall element 10 (sometimes referred to as Hall temperature).

  The Hall element 10 detects a magnetic field and outputs a signal according to the detected magnetic field. The resistance measuring unit 20 detects the Hall element resistance value of the Hall element 10. The determination circuit 30 is a determination unit that determines whether the Hall element resistance value increases or decreases due to a temperature change operation on the Hall element 10. In the present specification, the “Hall element resistance value” is not limited to the resistance value of the Hall element 10, and may include a signal of the Hall element 10 related to the resistance value of the Hall element 10. For example, the Hall element resistance value includes a potential difference between both ends in the driving direction of the Hall element 10 or a current value in the driving direction.

  The potential difference at both ends in the driving direction of the Hall element 10 or the current value in the driving direction refers to a potential difference or current value at both ends of the Hall element 10 in the driving direction of the Hall element 10 as well as constant current driving or constant voltage driving. In this specification, the driving direction is a direction in which a driving current flows in the Hall element 10 in the case of constant current driving, and a direction in which a current corresponding to the driving voltage flows in the Hall element 10 in the case of constant voltage driving.

  The temperature compensation unit 40 compensates the influence of the temperature on the output of the Hall element 10 based on the Hall element resistance value detected by the resistance measurement unit 20 and the determination result by the determination circuit 30. The temperature compensation unit 40 of this example adjusts the operation of the signal processing circuit 50. As an example, the temperature compensation unit 40 may adjust the gain of the signal processing circuit 50 by transmitting a gain adjustment signal Sg as a control signal to the signal processing circuit 50.

FIG. 2 shows an example of the relationship between temperature and sensitivity in the Hall element 10. As shown in FIG. 2, the sensitivity of the Hall element 10 (sometimes referred to as Hall sensitivity) varies depending on the Hall temperature. Hall sensitivity (Hole electromotive force V _H / magnetic flux density B) at the time of constant voltage driving is as follows. However, mu is the electron mobility, L is the width of the Hall element 10, W is the length of the Hall element 10, the V _in a driving voltage.

Hall sensitivity (Hole electromotive force V _H / magnetic flux density B) at the time of constant current driving is as follows. Here, _RH is the Hall coefficient, and d is the thickness of the Hall element 10.

In the example shown in FIG. 2, the Hall sensitivity decreases monotonously as the Hall temperature increases. That is, as the hole temperature increases, the Hall electromotive force V _H that is an output when the same magnetic flux density is applied decreases. Therefore, the Hall sensor 100 adjusts the output of the Hall element 10 according to the Hall temperature. Thereby, the hall sensor 100 cancels the influence on the output due to the hall temperature.

  In the Hall sensor 100 of this example, instead of detecting the Hall temperature by the temperature sensor, the Hall element resistance value of the Hall element 10 itself is detected. The Hall element resistance value varies depending on the Hall temperature. Therefore, the Hall temperature can be estimated using the Hall element 10 itself as a temperature sensor. According to this example, the Hall element resistance value of the Hall element 10 itself is directly detected instead of measuring the Hall temperature by the temperature sensor away from the Hall element 10. Therefore, the temperature characteristics of the Hall element 10 can be adjusted with high accuracy.

  FIG. 3 shows an example of the relationship between the temperature and the Hall element resistance value in the Hall element 10. In the Hall element 10 of this example, the Hall element resistance value changes so as to have an extreme value with respect to temperature. The Hall element 10 may change so that the Hall element resistance value has a maximum value with respect to temperature, or may change so as to have a minimum value. When the Hall element resistance value changes so as to have a maximum value with respect to the temperature, the temperature-resistance value characteristic of the Hall element 10 shows an upwardly convex graph characteristic. When the Hall element resistance value changes so as to have a minimum value with respect to temperature, the temperature-resistance value characteristic of the Hall element 10 shows a downwardly convex graph characteristic.

The Hall element 10 of this example may be formed of a compound semiconductor. The Hall element 10 may include InAs (indium arsenide). The Hall element 10 of this example changes so that the Hall element resistance value has a maximum value with respect to temperature. When the Hall element resistance value changes so as to have an extreme value with respect to temperature, at a plurality of temperatures that the temperature A and temperature B, the same Hall element resistance value R _s is detected. Therefore, only the Hall element resistance R _s, the temperature is not uniquely determined. Therefore, in the Hall sensor 100 of this example, a temperature change is caused in the Hall element 10, and a correct temperature is estimated by reading the change direction of the Hall element resistance value before and after the temperature change.

  In the example shown in FIG. 3, at the temperature A, the Hall element resistance value increases as the Hall temperature increases. On the other hand, at the temperature B, the Hall element resistance value decreases as the Hall temperature increases. Here, the temperature A is a temperature lower than a reference temperature at which the Hall element resistance value has a maximum value with respect to the temperature, and the temperature B is a temperature higher than the reference temperature. When the temperature change operation is performed so that the temperature change unit 60 increases the hall temperature, if the Hall element resistance value increases, it can be estimated that the hall temperature is the temperature A. On the other hand, in this case, if the Hall element resistance value decreases, it can be estimated that the Hall temperature is the temperature B.

  Conversely, when the temperature change unit 60 performs a temperature change operation so that the hole temperature decreases, if the Hall element resistance value decreases, it can be estimated that the hole temperature is the temperature A. On the other hand, if the Hall element resistance value increases in this case, it can be estimated that the Hall temperature is the temperature B. Therefore, according to the Hall sensor 100 of the present example, the Hall temperature can be uniquely estimated, so that the influence of the temperature on the output of the Hall element 10 can be accurately compensated.

  When the Hall element resistance value changes so as to have a minimum value with respect to the temperature, the Hall element resistance value decreases as the Hall temperature increases at a temperature A lower than the reference temperature indicating the minimum value. On the other hand, at the temperature B higher than the reference temperature, the Hall element resistance value increases as the Hall temperature increases. Therefore, even when the Hall element resistance value has a minimum value with respect to the temperature, the Hall temperature can be uniquely estimated.

FIG. 4 shows an example of the configuration of the Hall sensor 100 of the first embodiment. The temperature changing unit 60 of this example includes a heating element 62 and a heating element driving circuit 64. The heating element 62 may be disposed close to the Hall element 10. The heating element 62 heats the Hall element 10. The heating element driving circuit 64 temporarily changes the current flowing through the heating element 62. For example, the heating element driving circuit 64 causes a current to flow intermittently through the heating element 62. Heating element drive circuit 64 generates a heating element driving signal S _h, by sending to the heating element 62 may control the current supplied to the heating element 62.

The heating element drive signal _Sh may be a current itself flowing through the heating element 62 or a control signal for turning on / off the current flowing through the heating element 62. Heating element drive circuit 64, based on the heating element driving signal S _h, and generates a timing signal S _t of the temperature-change operation, may transmit a timing signal S _t to the determination circuit 30.

Resistance measuring unit 20 detects the detection signal S _d according to the drive state of the Hall element 10. In one example, the detection signal S _d is a voltage value or a current value detected from the Hall element 10. Detection signal S _d may include a driving voltage or a driving current for driving the Hall element 10. Resistance measuring unit 20, by calculation based on the detection signal S _d, and calculates the Hall element resistance. The resistance measurement unit 20 outputs the measured Hall element resistance value _Rh to the temperature compensation unit 40 as a resistance measurement signal _Sr.

Decision circuit 30 determines on the basis of the increase or decrease of the Hall element resistance value due to the temperature change operation on the Hall element 10 to the detection signal S _d. The determination circuit 30 detects the fluctuation direction of the Hall element resistance value detected during the driving of the heating element 62, that is, the direction in which the resistance value increases or decreases, and determines whether the temperature is A or B. Determine. The determination circuit 30 may calculate a difference value (differential value) of the Hall element resistance values before and after the temperature change operation. In this case, the temperature compensation unit 40 performs temperature compensation based on the difference value (differential value).

The determination circuit 30 may include a sample hold circuit and a comparator. Sample-and-hold circuit detecting and holding a detection signal S _d at the temperature predetermined state. Comparator compares the detection signal S _d to each other at the two temperature conditions. For example, the determination circuit 30 compares the voltage value of the Hall element 10 before and after the temperature change operation on the Hall element 10 with a comparator. When the current value flowing through the Hall element 10 is constant, if the voltage value of the Hall element 10 increases, it can be determined that the Hall element resistance value has increased. The determination circuit 30 outputs the determination result to the temperature compensation unit 40 as a determination result signal _Sj .

The temperature compensation unit 40 may include an adjustment circuit 42 and a storage unit 44. The adjustment circuit 42 controls the gain of the signal processing circuit 50 that amplifies the output signal of the Hall element 10 based on the determination result by the determination circuit 30. The gain of the signal processing circuit 50 is a gain that the signal processing circuit 50 gives to the output signal _So from the Hall element 10. Specifically, the adjustment circuit 42 includes a resistance measuring signal S _r determination result based on the signal S _j, may generate a gain adjustment signal S _g. The adjustment circuit 42 outputs the generated gain adjustment signal _Sg to the signal processing circuit 50 to adjust the gain of the signal processing circuit 50.

As shown in FIG. 2, when the Hall sensitivity decreases as the temperature increases, the output signal of the Hall element 10 decreases as the temperature increases. Therefore, the adjustment circuit 42 compensates for the influence of temperature on the output of the Hall element 10 by increasing the gain of the signal processing circuit 50. The adjustment circuit 42 may read the gain adjustment value from a table stored in advance in the storage unit 44 based on the resistance measurement signal _Sr and the determination result signal _Sj , and generate the gain adjustment signal Sg.

The storage unit 44 may store in advance a table indicating the relationship between the resistance measurement signal _Sr and the determination result signal _Sj and the corresponding gain. The resistance measurement signal _Sr may be the Hall element resistance value itself, or a potential difference between both ends in the driving direction of the Hall element 10 or a current value in the driving direction. However, the adjustment circuit 42 of this example is not limited to this case. The adjustment circuit 42 may generate the gain adjustment signal Sg by substituting the hole temperature into a predetermined calculation formula. In this case, the storage unit 44 may be omitted.

The adjustment circuit 42 may generate an offset adjustment signal for the signal processing circuit 50 based on the resistance measurement signal _Sr and the determination result signal _Sj . In this case, the adjustment circuit 42 outputs the generated offset adjustment signal to the signal processing circuit 50 to adjust the offset of the signal processing circuit 50. The adjustment circuit 42 may adjust both the gain and the offset of the signal processing circuit 50, or may adjust either one.

  FIG. 5 shows a processing flow of the adjustment method of the Hall sensor 100 according to the first embodiment. FIG. 6 shows an example of a signal waveform in each part of the Hall sensor 100 of the first embodiment. The adjustment method of the hall sensor 100 of this example will be described with reference to FIGS. 5 and 6.

  In the detection stage (step S101), the resistance measurement unit 20 detects the Hall element resistance value. In the temperature change stage (step S <b> 102), the temperature change unit 60 performs a temperature change operation to cause the Hall element 10 to change in temperature temporarily.

In this example, as shown in FIG. 6, the heating element driving signal S _h is turned on by the energization start time T1, is off at application end time T2. That is, the heating element 62 is energized at the energization start time T1 and energized at the energization end time T2. Heating element driving signal S _h may repeat off at a constant cycle. As a result, current flows intermittently through the heating element 62.

  The Hall temperature of the Hall element 10 temporarily heated by the heating element 62 rises for a certain period and reaches a maximum value at time T3 after the energization start time T1. As the energization of the heating element 62 ends, the hole temperature decreases. In this example, the rise time T4 is the time when the amount of change in the hall temperature with respect to the temperature before the energization start time T1 becomes the half value of the maximum value M, and the fall time T5 is the time when the half value is reached. To do. The hall temperature returns to the original temperature at the return time T6.

  In the determination step shown in FIG. 5 (step S103), the determination circuit 30 determines whether the Hall element resistance value increases or decreases due to a temperature change. As shown in FIG. 6, the Hall element resistance value increases or decreases according to the change in the Hall temperature. The determination circuit 30 may compare the Hall resistance value before the Hall element 10 is heated with the Hall resistance value after the heating. More specifically, the determination circuit 30 may compare the Hall element resistance value R1 at the time point P1 before the temperature change operation with the Hall element resistance value R2 at the time point P2 after the temperature change operation. Thereby, the determination circuit 30 may determine increase / decrease in the Hall element resistance value.

The time point P1 may be before the rise time T4 of the hall temperature, more preferably before the energization start time T1. The time point P1 may be a predetermined time before the energization start time T1 to the heating element 62. The predetermined time is, for example, 1 μs or more and 1000 μs or less. The time point P2 may be after the rise time T4 of the hall temperature and before the fall time T5, and more preferably set to match the time T3 when the Hall element resistance value becomes the maximum value M. . Judging circuit 30, based on the timing signal S _t from the temperature change unit 60, the time point P1 and point P2 may be set in synchronization with the temperature-change operation.

  If the Hall element resistance value R2 is larger than the Hall element resistance value R1, it is estimated that the Hall temperature before the temperature change operation is the temperature A. On the other hand, if the Hall element resistance value R2 is smaller than the Hall element resistance value R1, it is estimated that the Hall temperature before the temperature change operation is the temperature B.

  The determination circuit 30 may compare the Hall resistance value when the Hall element 10 is heated with the Hall resistance value when the Hall temperature returns to the original temperature after the heating is completed. More specifically, the determination circuit 30 may compare the Hall element resistance value R2 at the time point P2 immediately after the temperature change operation with the Hall element resistance value R3 at the time point P3 after the temperature change operation. Thereby, the determination circuit 30 may determine increase / decrease in the Hall element resistance value. The time point P2 immediately after the temperature change operation may be a time after the energization start time T1, preferably after the rise time T4 of the hall temperature and before the fall time T5, more preferably The Hall element resistance value may be set to coincide with time T3 when the local maximum value M is reached. The time point P3 after the temperature change operation may be after the falling time T5 of the hall temperature, and preferably after the return time T6.

  If the Hall element resistance value R3 is smaller than the Hall element resistance value R2, it can be estimated that the Hall temperature before the temperature change operation is the temperature A. If the Hall element resistance value R3 is larger than the Hall element resistance value R2, the temperature before the temperature change operation is estimated. It can be estimated that the hole temperature is temperature B.

  Next, in the temperature compensation stage (step S104) of FIG. 5, the temperature compensation unit 40 determines the Hall element based on the Hall element resistance value detected in the detection stage (step S101) and the determination result in the determination stage (step S103). Compensate for temperature effects on 10 outputs. The adjustment circuit 42 may adjust the gain or offset of the signal processing circuit 50.

  As described above, according to the Hall sensor 100 of this example, not only the Hall element resistance value but also the change direction of the Hall element resistance value at the time of temperature change operation is read to compensate the temperature of the output of the Hall sensor 100. Therefore, even in the Hall element 10 in which the Hall element resistance value changes so as to have an extreme value with respect to the temperature, the Hall temperature is uniquely estimated, and accurate temperature compensation corresponding to the Hall temperature can be realized. .

[Second Embodiment]
FIG. 7 shows an example of the configuration of the Hall sensor 100 of the second embodiment. The hall sensor 100 of this example includes a hold circuit 72 in addition to the configuration of the hall sensor 100 shown in FIG. Hold circuit 72, and outputs the held output signal S _o of the Hall element 10. The hold circuit 72 maintains the instantaneous value of the output signal _So of the Hall element 10 at the start of the hold over the hold period. The hold circuit 72 may transmit a held signal (sometimes referred to as a hold output signal) to the signal processing circuit 50.

In the hold period, even if the output signal _So of the Hall element 10 fluctuates, the hold output signal output via the hold circuit 72 does not fluctuate. Therefore, the hold circuit 72 may function as a signal mask circuit that masks fluctuations in the output signal So of the Hall element 10. The hold section may be set corresponding to the time during which the hall temperature is changing in accordance with the temperature changing operation by the temperature changing unit 60. In this example, the temperature change section 60 generates a timing signal S _t of the temperature-change operation, and sends a timing signal S _t to the hold circuit 72. Hold circuit 72, based on the timing signal S _t, it may determine when to terminate the timing and hold starts holding.

FIG. 8 shows an example of the hold interval. The temporal changes in the heating element drive signal _Sh and the hall temperature are the same as those described with reference to FIG. As shown in FIG. 8, the output signal S _o of the Hall element 10 changes according to the change in the Hall temperature. As described with reference to FIG. 2, the Hall sensitivity decreases as the temperature increases. Therefore, the hole temperature is temporarily increased, the output S _o of the Hall element 10 is temporarily reduced.

The hold section is set so as to include a section in which the output _So of the Hall element 10 is temporarily changed according to the temperature change operation. In this example, the hold period is set to the time between the P4 time point and the P5 time point. The hold start time point P4 may be before the energization start time T1 to the heating element 62, or may be a predetermined time before the energization start time T1. The predetermined time is set to, for example, 1 μs or more and 1000 μs or less.

Hold circuit 72, in synchronization with the heating element driving signal S _h, may hold the output signal S _o of the previous temperature change operation. The hold end point P5 may be after the return time T6 of the hall temperature or after a predetermined time from the return time T6. The predetermined time is set to, for example, 1 μs or more and 1000 μs or less. According to the hall sensor 100 of this example, since the hold circuit 72 that functions as a mask circuit is included, even if the hall sensitivity changes due to the temperature change operation by the temperature change unit 60, the output of the hall sensor 100 varies. Can be prevented.

[Third Embodiment]
FIG. 9 shows an example of the configuration of the Hall sensor 100 of the third embodiment. The hall sensor 100 of this example includes a hold circuit 74 in place of the hold circuit 72 in the configuration of the hall sensor 100 shown in FIG. The hold circuit 74 is provided on the rear stage side of the signal processing circuit 50. Other structures are the same as those in the second embodiment. The hold circuit 74 holds and outputs the output signal of the signal processing circuit 50. The hold circuit 74 maintains the instantaneous value of the signal processing circuit 50 at the start of the hold over the hold period. The hold circuit 74 may output a hold output signal to the output terminal OUT.

In the hold period, even if the output of the signal processing circuit 50 varies with the output signal _So of the Hall element 10, the hold output signal output through the hold circuit 74 does not vary. Similarly to FIG. 8, the hold section may be set corresponding to the time during which the hole temperature is changing in accordance with the temperature changing operation by the temperature changing unit 60. In this example, the temperature changing unit 60 generates a timing signal _St for the temperature changing operation and sends the timing signal _St to the hold circuit 74. Hold circuit 74, based on the timing signal S _t, it may determine when to terminate the timing and hold starts holding.

The hold section is set so as to include a section in which the output of the signal processing circuit 50 temporarily changes according to the temperature change operation. The hold start time point P4 may be before the energization start time T1 to the heating element 62. Hold circuit 74, in synchronization with the heating element driving signal S _h, may hold the output signal of a previous signal processing circuit 50 of the temperature-change operation. The hold end time P5 may be after the hall temperature return time T6 or after a predetermined time from the return time T6. The predetermined time is set to 1 μs or more and 1000 μs or less, for example.

  According to the hall sensor 100 of the present example, even when the hall sensitivity changes in accordance with the temperature change operation by the temperature changing unit 60, the fluctuation of the output of the signal processing circuit 50 due to the change in hall sensitivity can be prevented. Can do.

[Fourth Embodiment]
FIG. 10 shows an example of the configuration of the Hall sensor 100 of the fourth embodiment. In the Hall sensor 100 of this example, the signal processing circuit 50 includes an AD changing circuit (A / D conversion circuit) 52 and a digital signal processing circuit 54. On the other hand, since the AD conversion circuit 52 serves as the hold circuit 72, the separate hold circuit 72 may be omitted. Except for these points, the configuration of the Hall sensor 100 of this example is the same as that of the Hall sensor 100 shown in FIG.

  The AD conversion circuit 52 receives the output signal So of the Hall element 10, samples the output signal So, and converts it into a digital value. The AD conversion circuit 52 may sample the output signal amplified by an amplifier or the like and convert it to a digital value instead of the output signal So of the Hall element 10. The AD conversion circuit 52 supplies the converted digital signal to the digital signal processing circuit 54. The digital signal processing circuit 54 may be connected to the AD conversion circuit 52. Based on the signal received from the AD conversion circuit 52, the digital signal processing circuit 54 performs digital signal processing according to the application of the Hall sensor 100, and calculates a signal output to the output terminal OUT.

The AD conversion circuit 52 samples and holds the output signal So of the Hall element 10 at a predetermined sampling period. In this example, the AD conversion circuit 52 samples and holds the output of the Hall element 10 before the temperature change operation in accordance with the cycle of the temperature change operation. Therefore, the sampling period of the AD converter 52 may be synchronized with the period of the heating element driving signal S _h. Heating element drive circuit 64, based on the heat generating element drive signal Sh, and generates a timing signal S _t of the temperature-change operation, may be sent to the timing signal S _t AD converter 52 not judging circuit 30 only .

  The AD conversion circuit 52 may sample the output of the Hall element 10 a predetermined time before the energization start time T1 to the heating element 62. The predetermined time is, for example, 1 μsec or more and 1000 μsec.

  According to this example, the AD conversion circuit 52 can sample a signal at a timing that is not affected by the temperature change operation. In other words, the AD conversion circuit 52 samples and holds the output of the Hall element 10 before the temperature change operation in accordance with the cycle of the temperature change operation. Therefore, even if the Hall sensitivity changes due to the temperature change operation by the temperature change unit 60, it is possible to prevent the digital signal converted by the AD conversion circuit 52 from fluctuating. The AD conversion circuit 52 functions not only as an analog-digital conversion necessary for digital signal processing but also as a mask circuit. Therefore, in addition to the AD conversion circuit 52, separate hold circuits 72 and 74 are not required.

  FIG. 11 shows an example of the configuration of the Hall sensor 100 of the fifth embodiment. The temperature changing unit 60 of this example does not have a separate heating element 62. Except for the configuration of the temperature changing unit 60, the Hall sensor of this example is the same as the configuration of the Hall sensor 100 shown in FIG. The hall sensor 100 has a signal processing circuit 50.

  In this example, the temperature changing unit 60 causes the Hall element 10 to change in temperature by changing the heat generated from the signal processing circuit 50. Therefore, the signal processing circuit 50 itself that is a signal processing unit that amplifies the output signal of the Hall element 10 is used as a heat source. That is, the signal processing circuit 50 takes charge of a part of the function of the temperature changing unit 60 as a heat source. The signal processing circuit 50 may be disposed close to the Hall element 10. The temperature changing unit 60 includes a power control circuit 66. The power control circuit 66 temporarily reduces the power supplied to the signal processing circuit 50. The power control circuit 66 may control the power supplied to the signal processing circuit 50 within a predetermined range.

When the power supplied from the power control circuit 66 to the signal processing circuit 50 is reduced, the amount of heat generated by the signal processing circuit 50 is reduced and the hall temperature is lowered. On the other hand, when the power supplied from the power control circuit 66 to the signal processing circuit 50 is increased, the amount of heat generated by the signal processing circuit 50 increases and the hall temperature rises. The power control circuit 66 generates a power control signal S _p, and transmits to the signal processing circuit 50. The power control circuit 66 increases or decreases the power supplied to the signal processing circuit 50 based on the power control signal S _p.

In one example, the power control circuit 66 changes at least one of the supply voltage and the supply current supplied to the signal processing circuit 50 to increase or decrease the supply power to the signal processing circuit 50. The power control signal _Sp may be the supply voltage or supply current itself to the signal processing circuit 50, or may be a control signal that increases or decreases the supply voltage or supply current to the signal processing circuit 50. The power control circuit 66 generates a timing signal S _t of the temperature-change operation, it may transmit a timing signal S _t to the decision circuit 30 and the hold circuit 74.

[Fifth Embodiment]
FIG. 12 shows an example of a signal waveform in each part of the Hall sensor 100 of the fifth embodiment. The power control circuit 66 may perform control so that the power supplied to the signal processing circuit 50 is reduced at the power reduction start time T1, and the power supplied to the signal processing circuit 50 is recovered at the power reduction end time T2. In this case, the power supplied to the signal processing circuit 50 between time T1 and time T2 is 80% or less compared to the power supplied to the signal processing circuit 50 at a time before the power reduction start time T1. More preferably, it may be 50% or less. The power control circuit 66 may perform control so that a temporary decrease in the power supplied to the signal processing circuit 50 is repeated intermittently.

  The Hall element 10 is heated by the signal processing circuit 50 at a time before the power reduction start time T1. As the power supplied to the signal processing circuit 50 decreases after the power decrease start time T1 and the amount of heat generated by the signal processing circuit 50 decreases, the Hall temperature of the Hall element 10 decreases for a certain period of time. The local minimum value is reached at time T3 after T1. As the power supplied to the signal processing circuit 50 is recovered, the hall temperature rises. In this example, the fall time at which the amount of change in the hall temperature with respect to the temperature before the power decrease start time T1 is half of the minimum value N is T4, and the rise time for returning to the half value is T5. To do. The hall temperature returns to the original temperature at the return time T6.

  The determination circuit 30 determines increase / decrease in the Hall element resistance value due to temperature change. The determination circuit 30 may compare the Hall element resistance value R1 at the time point P1 before the temperature change operation with the Hall element resistance value R2 at the time point P2 after the temperature change operation. Thereby, the determination circuit 30 may determine increase / decrease in the Hall element resistance value. The time point P1 may be before the rise time T4 of the hall temperature, and more preferably before the power decrease start time T1. The time point P1 may be a predetermined time before the power decrease start time T1. The predetermined time is, for example, 1 μs or more and 1000 μs or less.

The time point P2 may be after the falling time T4 of the hall temperature and before the rising time T5, and more preferably set so as to match the time T3 at which the hall temperature becomes the minimum value. Judging circuit 30, based on the timing signal S _t from the temperature change unit 60, the time point P1 and point P2 may be set in synchronization with the temperature-change operation.

  The hall sensor 100 has a hold circuit 74. The hold circuit 74 may be provided on the rear stage side of the signal processing circuit 50. The hold circuit 74 maintains the instantaneous value of the signal processing circuit 50 at the start of the hold over the hold period. The hold circuit 74 may output a hold output signal to the output terminal OUT.

In the hold period, the hold output signal output via the hold circuit 74 does not fluctuate. Similarly to FIG. 8, the hold section may be set corresponding to the time during which the hole temperature is changing in accordance with the temperature changing operation by the temperature changing unit 60. The hold section masks output fluctuations of the Hall sensor 100 in the section where the output _So of the Hall element 10 is temporarily changed according to the temperature change operation and the section where the power supplied to the signal processing circuit 50 is decreased. To do.

  In this example, the hold period is set to the time between the P4 time point and the P5 time point. The hold start time point P4 may be a predetermined time before the power decrease start time T1. In one example, the predetermined time is set to 1 μs or more and 1000 μs or less. The hold end point P5 may be after a predetermined time from the hall temperature return time T6. In one example, the predetermined time is set to 1 μs or more and 1000 μs or less.

  According to the Hall sensor 100 of this example, a temperature change operation can be applied to the Hall element 10 without providing a separate heating element 62. Therefore, a space for arranging the separate heating element 62 is not required, and the Hall sensor 100 can be downsized. In addition, since the hold circuit 74 that functions as a mask circuit is provided, the output of the Hall sensor 100 is prevented from fluctuating even if the driving state of the signal processing circuit 50 changes as the power supplied to the signal processing circuit 50 decreases. can do.

[Sixth Embodiment]
FIG. 13 shows an example of the configuration of the Hall sensor 100 of the sixth embodiment. The temperature changing unit 60 of this example does not have a separate heating element 62. Except for the configuration of the temperature changing unit 60, the Hall sensor 100 of this example is the same as the configuration of the Hall sensor 100 shown in FIG. The resistance measurement unit 20 acquires the current I _in and the voltage V _in detected from the Hall element 10 as the detection signal S _d . The resistance measurement unit 20 calculates the Hall element resistance value R _h based on the current I _in and the voltage V _in . Thus, the resistance measuring section 20 measures the Hall element resistance R _h.

The current I _in is a current _in the driving direction of the Hall element 10. That is, when the Hall element 10 is driven at a constant current, the current I _in becomes the drive current I _in . Voltage V _in is the voltage value across the driving direction of the Hall element 10. Voltage V _in, when the Hall element 10 is a constant voltage drive, a drive voltage of the Hall element 10.

Resistance measuring unit 20, the measured resistance value R _h as a resistance measuring signal S _r, and output to the temperature compensation unit 40. On the other hand, the determination circuit 30 determines based on the increase or decrease of the Hall element resistance value due to the temperature change operation on the Hall element 10 to the current I _in and the voltage V _in. The determination circuit 30 outputs the determination result to the temperature compensation unit 40 as a determination result signal _Sj .

The temperature compensation unit 40 of this example includes an adjustment circuit 42 and a storage unit 44. The adjustment circuit 42 controls the gain of the signal processing circuit 50 that amplifies the output signal of the Hall element 10 based on the determination result by the determination circuit 30. Specifically, the adjustment circuit 42 includes a resistance measuring signal S _r determination result based on the signal S _j, may generate a gain adjustment signal S _g. The adjustment circuit 42 outputs the generated gain adjustment signal _Sg to the signal processing circuit 50 to adjust the gain of the signal processing circuit 50.

In this example, the temperature changing unit 60 includes a current control circuit 68. The current control circuit 68 executes the temperature change operation by temporarily changing the current I _in flowing in the driving direction of the Hall element 10. That is, the current control circuit 68 controls the Hall element 10 itself to be heated by temporarily changing the current I _in flowing in the drive direction of the Hall element 10. For example, the current control circuit 68 temporarily increases the current I _in flowing through the Hall element 10 to a predetermined value.

The Hall sensor 100 of this example includes a current source 80 that supplies a driving current I _in to the Hall element 10. The current control circuit 68 controls the current source 80 may control the driving current I _in supplied to the Hall element 10. The current control circuit 68 may control the current source 80 by generating a current control signal S _i and transmitting it to the current source 80. The current control circuit 68 generates a timing signal S _t of the temperature-change operation, it may transmit a timing signal S _t to the determination circuit 30. That is, in this example, the Hall element 10 itself and the current source 80 are responsible for a part of the function of the temperature changing unit 60.

The signal waveform in each part of the Hall sensor 100 of this example is the same as the signal waveform of FIG. 6 shown as the first embodiment. Signal waveform of this example are similar except that they are controlled based on the current control signal S _i in place of the control based on the heating element driving signal S _h in FIG. Therefore, the operation of the hall sensor 100 of this example will be described with reference to FIG. The current control circuit 68 increases the current I _in flowing in the driving direction of the Hall element 10 at the current increase start time T1, and returns the current I _in to the state before the increase at the current increase end time T2.

  The determination circuit 30 may compare the Hall element resistance value R1 at the time point P1 before the temperature change operation with the Hall element resistance value R2 at the time point P2 after the temperature change operation. Preferably, the time point P1 may be before the current increase start time T1 to the Hall element 10. Preferably, the time point P2 may be after the current increase end time T2 to the Hall element 10 and before the fall time T5 of the Hall element 10.

  That is, it is desirable that the determination circuit 30 compares the Hall element resistance values R1 and R2 measured in a state where the current supplied to the Hall element 10 is not increased. Thus, even when the Hall element resistance value has nonlinear resistance, the determination circuit 30 can determine increase / decrease in the Hall element resistance value due to the resistance value temperature change. Also in this example, the Hall sensor 100 may include the hold circuit 72, the hold circuit 74, and the AD conversion circuit 52 as shown in FIGS. 7, 9, and 10.

  According to the Hall sensor 100 of this example, a temperature change operation can be applied to the Hall element 10 without providing a separate heating element 62. Therefore, a space for arranging the separate heating element 62 is not required, and the Hall sensor 100 can be downsized. In addition, since the Hall element 10 itself can be directly heated, the heating efficiency is higher than in the case where the Hall element 10 is heated by another heating element 62 and the like, and the response to the temperature change operation is fast.

[Seventh Embodiment]
FIG. 14 shows an outline of the configuration of the Hall sensor 100 of the seventh embodiment. The temperature compensation unit 40 of this example compensates for the influence of the temperature on the output of the Hall element 10 by adjusting the Hall sensitivity instead of adjusting the gain or offset of the signal processing circuit 50. Except for the configuration of the temperature compensation unit 40, the configuration of this example is the same as that of the first to sixth embodiments shown in FIGS. Therefore, repeated description is omitted.

The temperature compensation unit 40 adjusts the operation of the Hall element 10 itself based on the Hall element resistance value detected by the resistance measurement unit 20 and the determination result by the determination circuit 30. Temperature compensating section 40 outputs a control signal S _c for compensating the temperature characteristics of the Hall element 10 to the Hall element 10 may adjust the operation of the Hall element 10.

FIG. 15 shows an example of the configuration of the Hall sensor 100 of the seventh embodiment. The temperature changing unit 60 includes a heating element 62 and a heating element driving circuit 64. However, the temperature changing unit 60 is not limited to this case, and has a power control circuit 66 that temporarily reduces the power supplied to the signal processing circuit 50 instead of the heating element 62, as shown in FIG. Alternatively, as shown in FIG. 13, a current control circuit 68 that performs a temperature change operation by temporarily changing the current I _in flowing in the driving direction of the Hall element 10 may be provided.

The resistance measuring unit 20 measures the Hall element resistance value R _h based on the current I _in and the voltage V _in . The current I _in is a current value in the driving direction of the Hall element 10. That is, when the Hall element 10 is driven at a constant current, the current I _in becomes the drive current I _in . Voltage V _in is the voltage value across the driving direction of the Hall element 10. Resistance measuring unit 20, the measured resistance value R _h as a resistance measuring signal S _r, and output to the temperature compensation unit 40.

Decision circuit 30 determines on the basis of the increase or decrease of the Hall element resistance value due to the temperature change operation on the Hall element 10 to the current I _in and the voltage V _in. The determination circuit 30 outputs the determination result to the temperature compensation unit 40 as a determination result signal _Sj .

The temperature compensation unit 40 may include an adjustment circuit 42 and a storage unit 44. The adjustment circuit 42 in this example controls the drive current I _in applied to the Hall element 10 based on the determination result by the determination circuit 30. The Hall sensor 100 of this example includes a current source 80 that supplies a driving current I _in to the Hall element 10. The temperature compensation unit 40 may control the current source 80 to adjust the drive current I _in supplied to the Hall element 10.

As shown in FIG. 2, when the Hall sensitivity decreases as the temperature increases, the output signal of the Hall element 10 decreases as the temperature increases. Thus, the adjustment circuit 42, as the temperature increases, by increasing the driving current I _in, to compensate for the effects of temperature on the output of the Hall element 10. The storage unit 44 includes a resistance measuring signal S _r and the determination result signal S _j, the table showing the relationship between the adjustment value of the corresponding driving current I _in may be stored in advance. Adjusting circuit 42, the resistance measurement signal based on the S _r and the determination result signal S _j, from a table stored in advance in the storage unit 44, reads the adjustment value of the drive current I _in to be set, the drive current I a control signal S _c for adjusting the _in may generate.

The resistance measurement signal _Sr may be the Hall element resistance value itself, or a potential difference between both ends in the driving direction of the Hall element 10 or a current value in the driving direction. However, the adjustment circuit 42 of this example is not limited to this case. The adjustment circuit 42 may calculate the adjustment value of the drive current I _in by substituting the hole temperature into a predetermined calculation formula. In this case, the storage unit 44 may be omitted.

  Also in this example, the Hall sensor 100 may include the hold circuit 72, the hold circuit 74, or the AD conversion circuit 52 as illustrated in FIGS. The signal processing circuit 50 is not necessarily required.

  Also by the Hall sensor 100 of this example, not only the Hall element resistance value but also the change direction of the Hall element resistance value at the time of temperature change operation is read to compensate the temperature of the output of the Hall sensor 100. Therefore, even in the Hall element 10 in which the Hall element resistance value changes so as to have an extreme value with respect to the temperature, the Hall temperature is uniquely estimated, and accurate temperature compensation corresponding to the Hall temperature can be realized. .

[Eighth Embodiment]
FIG. 16 shows an example of the configuration of the Hall sensor 100 of the eighth embodiment. The hall sensor 100 of this example drives the hall element 10 at a constant voltage. The hall sensor 100 includes an ammeter 82. The temperature compensation unit 40 controls the drive voltage applied to the Hall element 10 based on the determination result by the determination circuit 30. Except for these points, the other configuration is the same as that of the seventh embodiment shown in FIG.

Hall element 10 is a constant voltage driven by the driving power _{V in.} The ammeter 82 detects a current I _in flowing through the Hall element 10 in accordance with the drive voltage V _in . The resistance measuring unit 20 measures the Hall element resistance value R _h based on the current I _in and the voltage V _in . Resistance measuring unit 20, the measured resistance value R _h as a resistance measuring signal S _r, and output to the temperature compensation unit 40. Decision circuit 30 determines on the basis of the increase or decrease of the Hall element resistance value due to the temperature change operation on the Hall element 10 to the current I _in and the voltage V _in. The determination circuit 30 outputs the determination result to the temperature compensation unit 40 as a determination result signal _Sj .

The temperature compensation unit 40 may include an adjustment circuit 42 and a storage unit 44. The adjustment circuit 42 of this example controls the drive voltage applied to the hall element 10 based on the determination result by the determination circuit 30. Adjusting circuit 42 of the present embodiment adjusts the driving voltage V _in a potential difference between both ends in the driving direction of the Hall element 10. As shown in FIG. 2, when the Hall sensitivity decreases as the temperature increases, the output signal of the Hall element 10 decreases as the temperature increases. Thus, the adjustment circuit 42, as the temperature increases, by increasing the driving voltage V _in, to compensate for the effects of temperature on the output of the Hall element 10.

Adjusting circuit 42, the resistance measurement signal based on the S _r and the determination result signal S _j, from a table stored in advance in the storage unit 44, reads the adjustment value of the drive voltage V _in to be set, the drive voltage V _in may be adjusted.

For example, the storage unit 44 includes a resistance measuring signal S _r and the determination result signal S _j, the table showing the relationship between the adjustment value of the corresponding drive voltage V _in is stored in advance. The resistance measurement signal _Sr may be the Hall element resistance value itself, or a potential difference between both ends in the driving direction of the Hall element 10 or a current value in the driving direction. However, the adjustment circuit 42 of this example is not limited to this case. Adjusting circuit 42, a predetermined calculation formula by substituting the hole temperature may calculate the adjustment value of the drive voltage V _in. In this case, the storage unit 44 may be omitted.

  Also in this example, the Hall sensor 100 may include the hold circuit 72, the hold circuit 74, or the AD conversion circuit 52 as illustrated in FIGS. The signal processing circuit 50 is not necessarily required. Also by the hall sensor 100 of this example, the hall temperature is uniquely estimated, and accurate temperature compensation corresponding to the hall temperature can be realized.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Each embodiment can be combined with each other. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the operation flow in the claims, the description, and the drawings is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 ... Hall element, 20 ... Resistance measurement part, 30 ... Determination circuit, 40 ... Temperature compensation part, 42 ... Adjustment circuit, 44 ... Memory | storage part, 50 ... Signal processing Circuit 52... AD conversion circuit 54 digital signal processing circuit 60 temperature change unit 62 heating element 64 heating element drive circuit 66 power control circuit 68 ... Current control circuit, 72 ... Hold circuit, 74 ... Hold circuit, 80 ... Current source, 82 ... Ammeter, 100 ... Hall sensor

Claims (14)

Hall element that changes so that the Hall element resistance value has an extreme value with respect to temperature,
A resistance measuring unit for detecting a Hall element resistance value of the Hall element;
A determination unit for determining increase / decrease in Hall element resistance value by temperature change operation on the Hall element;
Based on the Hall element resistance value detected by the resistance measurement unit and the determination result by the determination unit, a temperature compensation unit that compensates for the influence of temperature on the output of the Hall element;
Hall sensor equipped with. The hall sensor according to claim 1, further comprising a temperature changing unit that performs the temperature changing operation on the hall element. The temperature changing part has a heating element for heating the Hall element,
The temperature changing unit temporarily changes a current flowing through the heating element;
The hall sensor according to claim 2. The temperature changing unit temporarily changes a current flowing in a driving direction of the Hall element;
The hall sensor according to claim 2. A signal processing unit for amplifying the output signal of the Hall element;
The temperature changing unit temporarily reduces the power supplied to the signal processing unit;
The hall sensor according to claim 2. A hold circuit that holds and outputs the output signal of the Hall element before the temperature change operation;
The hall sensor according to any one of claims 1 to 5. A hold circuit that holds and outputs the output signal of the signal processing unit that amplifies the output signal of the Hall element before the temperature change operation;
The hall sensor according to any one of claims 1 to 5. The signal processing unit that amplifies the output signal of the Hall element includes an AD conversion circuit that samples and converts the output signal of the Hall element before the temperature change operation.
The hall sensor according to any one of claims 1 to 5. The determination unit determines increase or decrease of the Hall element resistance value by comparing the Hall element resistance value before the temperature change operation and the Hall element resistance value after the temperature change operation.
The hall sensor according to any one of claims 1 to 8. The determination unit increases or decreases the Hall element resistance value by comparing the Hall element resistance value immediately after the temperature change operation with the Hall element resistance value after a predetermined time has elapsed since the temperature change operation. judge,
The hall sensor according to any one of claims 1 to 8. The temperature compensation unit includes an adjustment circuit that controls a drive current or a drive voltage applied to the Hall element based on the determination result.
The hall sensor according to any one of claims 1 to 10. The temperature compensation unit has an adjustment circuit that controls at least one of a gain and an offset that a signal processing unit that amplifies the output signal of the Hall element gives to the output from the Hall element based on the determination result,
The hall sensor according to any one of claims 1 to 10. The Hall element includes InAs.
The hall sensor according to any one of claims 1 to 12. A Hall sensor adjustment method comprising a Hall element that changes so that the Hall element resistance value has an extreme value with respect to temperature,
A detection step of detecting a Hall element resistance value of the Hall element;
A temperature change step for changing the temperature of the Hall element;
A determination step of determining increase / decrease in Hall element resistance value due to the temperature change;
A Hall sensor adjustment method comprising: a temperature compensation stage that compensates for an effect of temperature on the output of the Hall element based on the Hall element resistance value detected in the detection stage and the determination result in the determination stage.

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