阅读说明：本技术 霍尔传感器开关及电子设备 (Hall sensor switch and electronic equipment ) 是由 邹晓磊 张志红 皮永祥 于 2021-07-13 设计创作，主要内容包括：本申请公开一种霍尔传感器开关和电子设备,所述霍尔传感器开关包括：霍尔元件,具有第一控制端、第二控制端、第一输出端以及第二输出端,所述第一控制端与电源电压之间串联有第一电阻,所述第二控制端接地；比较模块,连接至所述霍尔元件的所述第一输出端和第二输出端,根据所述第一输出端和所述第二输出端之间的差分电压的大小,输出相应的开关控制信号；温度补偿模块,用于向所述第一输出端输入补偿电流,使得所述比较模块输出的开关控制信号发生翻转时所对应的磁场大小与所述霍尔元件灵敏度的温度系数无关。上述霍尔传感器开关的稳定性较高。(The application discloses hall sensor switch and electronic equipment, hall sensor switch includes: the Hall element is provided with a first control end, a second control end, a first output end and a second output end, a first resistor is connected between the first control end and a power supply voltage in series, and the second control end is grounded; the comparison module is connected to the first output end and the second output end of the Hall element and outputs corresponding switch control signals according to the magnitude of differential voltage between the first output end and the second output end; and the temperature compensation module is used for inputting compensation current to the first output end, so that the size of the corresponding magnetic field when the switch control signal output by the comparison module is turned over is irrelevant to the temperature coefficient of the sensitivity of the Hall element. The stability of the Hall sensor switch is high.)

1. A hall sensor switch, comprising:

the Hall element is provided with a first control end, a second control end, a first output end and a second output end, a first resistor is connected between the first control end and a power supply voltage in series, and the second control end is grounded;

the comparison module is connected to the first output end and the second output end of the Hall element and outputs corresponding switch control signals according to the magnitude of differential voltage between the first output end and the second output end;

and the temperature compensation module is used for inputting compensation current to the first output end, so that the size of the corresponding magnetic field when the switch control signal output by the comparison module is turned over is irrelevant to the temperature coefficient of the sensitivity of the Hall element.

2. The hall sensor switch of claim 1 wherein the comparison module comprises a first amplifier and a comparator connected to an output of the first amplifier; the positive input end of the first amplifier is connected to the second output end of the Hall element, the negative input end of the first amplifier is connected to the first output end of the Hall element, and the output ends of the first amplifier are connected to the two input ends of the comparator, so that the differential voltage between the first output end and the second output end is amplified and then output to the comparator; and the comparator outputs corresponding switch control signals according to the input differential voltage.

3. The hall sensor switch of claim 1 wherein the temperature compensation module comprises: the second resistor is connected in series between a power supply voltage and a fixed potential end, the fixed potential end has a fixed potential and is connected to the first output end of the Hall element; the second resistor has the same electron mobility as the Hall element at the same temperature.

4. The hall sensor switch of claim 1 wherein the temperature compensation module further comprises: and the positive input end of the clamp amplifier is connected to the first control end of the Hall element, the negative input end of the clamp amplifier is connected to the fixed potential end, and the output end of the clamp amplifier is connected to the negative input end of the clamp amplifier.

5. The hall sensor switch of claim 4 wherein a switching element is connected between the fixed potential terminal and the first output terminal of the hall element, and the output terminal of the clamp amplifier is connected to a control terminal of the switching element.

6. The Hall sensor switch of claim 5, wherein the switching element is a PMOS transistor, the output of the clamp amplifier is connected to the gate of the PMOS transistor, the source of the PMOS transistor is connected to the negative input of the clamp amplifier, and the drain of the PMOS transistor is connected to the first output of the Hall element.

7. The hall sensor switch of claim 3 wherein the second resistance is of the same type as the resistance of the hall element.

8. The hall sensor switch of claim 3 wherein the second resistor is a square resistor.

9. The Hall sensor switch according to claim 8, wherein when the switch control signal outputted from the comparing module is inverted, the corresponding electromagnetic field has a magnitude of B,wherein R is₀Is the resistance value of the first resistor, q is the charge constant, n is the electron concentration, W is the width of the second resistor, L is the length of the second resistor, d is the thickness of the second resistor, v is the charge movement speed, W 'is the width of the Hall disk, and L' is the length of the Hall disk.

10. The hall sensor switch of claim 1 wherein the hall element is a square hall plate, the first and second control terminals are located at two opposite corners of the square hall plate, and the first and second output terminals are located at the other two opposite corners of the square hall plate.

11. An electronic device, comprising: the hall sensor switch of claims 1 to 10.

Technical Field

The application relates to the technical field of Hall sensing, in particular to a Hall sensor switch and electronic equipment.

Background

The Hall device is a magnetic sensor manufactured based on the Hall effect principle, the Hall effect is one of electromagnetic effects, when current passes through a conductor in a direction perpendicular to an external magnetic field, an additional electric field is generated in the conductor in a direction perpendicular to the current and the magnetic field, so that a potential difference is generated at two ends of the conductor, the phenomenon is the Hall effect, and the potential difference is called as Hall potential difference.

The Hall device is integrated in the Hall sensor switch, and the sensor switch has the characteristics of low power consumption, high sensitivity, high input and output isolation degree and the like, and is widely applied to the fields of industry, communication, instrument manufacturing and the like.

Referring to fig. 1, a functional diagram of a unipolar (south pole) hall switch is shown. When the south pole of the magnet is close to the surface of the Hall sensor switch chip, and when the magnetic field intensity sensed by the chip is greater than the magnetic field threshold BOP, the output of the Hall sensor switch is changed from high level to low level.

In many applications, hall sensor switches are required to operate over a wide temperature range. For example, in the sensor switch product in the automobile industry, the working temperature range is required to be-40-125 ℃, in the sensor switch product in the military industry, the working temperature range is required to be-55-150 ℃, and the larger working temperature range has high requirements on the temperature characteristics of the Hall sensor switch. The most important parameter of the hall sensor switch is sensitivity, and the hall switch is required to maintain stable sensitivity in a wide temperature range, so that the temperature coefficient of the sensitivity of the hall switch is required to be small.

When the external temperature of a Hall sensor switch in the prior art changes, the sensitivity of a Hall device changes, so that a detection result has certain deviation, and the requirement of a wide working temperature range cannot be met.

Disclosure of Invention

In view of this, the present application provides a hall sensor switch and an electronic device, so as to solve the problem that the existing hall sensor switch is poor in stability.

The application provides a hall sensor switch, includes: the Hall element is provided with a first control end, a second control end, a first output end and a second output end, a first resistor is connected between the first control end and a power supply voltage in series, and the second control end is grounded; the comparison module is connected to the first output end and the second output end of the Hall element and outputs corresponding switch control signals according to the magnitude of differential voltage between the first output end and the second output end; and the temperature compensation module is used for inputting compensation current to the first output end, so that the corresponding magnetic field size is irrelevant to the temperature coefficient of the sensitivity of the Hall element when the switch control signal output by the comparison module is turned over.

Optionally, the comparing module includes a first amplifier and a comparator connected to an output terminal of the first amplifier; the positive input end of the first amplifier is connected to the second output end of the Hall element, the negative input end of the first amplifier is connected to the first output end of the Hall element, and the output ends of the first amplifier are connected to the two input ends of the comparator, so that the differential voltage between the first output end and the second output end is amplified and then output to the comparator; and the comparator outputs corresponding switch control signals according to the input differential voltage.

Optionally, the temperature compensation module includes: the second resistor is connected in series between a power supply voltage and a fixed potential end, the fixed potential end has a fixed potential and is connected to the first output end of the Hall element; the second resistor has the same electron mobility as the Hall element at the same temperature.

Optionally, the temperature compensation module further includes: and the positive input end of the clamp amplifier is connected to the first control end of the Hall element, the negative input end of the clamp amplifier is connected to the fixed potential end, and the output end of the clamp amplifier is connected to the negative input end of the clamp amplifier.

Optionally, a switching element is connected between the fixed potential end and the first output end of the hall element, and the output end of the clamp amplifier is connected to the control end of the switching element.

Optionally, the switch element is a PMOS transistor, an output end of the clamp amplifier is connected to a gate of the PMOS transistor, a source of the PMOS transistor is connected to a negative input end of the clamp amplifier, and a drain of the PMOS transistor is connected to the first output end of the hall element.

Optionally, the second resistor is of the same type as the hall element.

Optionally, the second resistor is a square resistor.

Optionally, when the switch control signal output by the comparing module is inverted, the corresponding electromagnetic field is B,wherein R is₀Is the resistance value of the first resistor, q is the charge constant, n is the electron concentration, W is the width of the second resistor, L is the length of the second resistor, d is the thickness of the second resistor, v is the charge movement speed, W 'is the width of the Hall disk, and L' is the length of the Hall disk.

Optionally, the hall element is a square hall disc, the first control end and the second control end are respectively located at two opposite vertex angles, and the first output end and the second output end are located at the other two opposite vertex angles.

The application also provides an electronic device comprising the Hall sensor switch.

According to the Hall sensor switch, compensation current is input to one output end of the Hall element through the compensation circuit, so that when the switch control signal output by the comparison module is turned over, the corresponding magnetic field size is irrelevant to the temperature coefficient of the sensitivity of the Hall element. Under the condition that the temperature stability of other modules is higher, the sensitivity of the Hall sensor switch can also ensure higher stability.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a functional schematic of a unipolar Hall sensor switch;

fig. 2 is a schematic diagram of an internal structure of a conventional hall sensor switch;

FIG. 3 is a schematic structural diagram of a Hall sensor switch according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a hall sensor switch according to an embodiment of the present application.

Detailed Description

As described in the background art, the sensitivity of the conventional hall sensor switch changes with temperature, and cannot meet the requirement of a wide temperature range.

Fig. 2 is a schematic diagram of an internal structure of a conventional hall sensor switch.

The main body architecture of the Hall sensor switch comprises a Hall disc, an amplifier AMP and a comparator COMP, wherein the Hall disc in the circuit can be equivalent to a Wheatstone bridge, and the equivalent resistance value of the Hall disc is set as R_HHas four ports H1-H4. The voltage from terminal H1 to terminal H3 isWhen a magnetic field with the magnetic induction intensity of B is vertically applied to the Hall disc, H4-H2 output Hall voltages of:

wherein, K_HIs the hall sensitivity.

Hall voltage V_HAfter being amplified by the amplifier AMP, the amplified voltage is compared with the reference voltage Vref, and the input differential voltage of the comparator is:

where A is the amplification factor of the amplifier AMP.

As can be derived from equation (2), the temperature coefficient of the input differential voltage of the comparator COMP is substantially determined by the temperature coefficient of the hall sensitivity. Because the carrier concentration and the like in the Hall disc change along with the temperature change, the internal resistance, the Hall potential and the like of the Hall disc also change along with the temperature change, so that the sensitivity of the Hall device changes, and further, the detection result also has certain deviation.

The invention provides a novel Hall sensor switch circuit, which improves the stability of the sensitivity of a Hall sensor switch.

The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The following embodiments and their technical features may be combined with each other without conflict.

Fig. 3 is a schematic structural diagram of a hall sensor switch according to an embodiment of the invention.

The hall sensor switch includes a hall element 110, a comparison module 120, and a temperature compensation module 130.

The hall element 10 includes a first control terminal H1, a second control terminal H3, a first output terminal H2, and a second output terminal H4. The first control terminal H1 and the second control terminal H3 are used for applying a control voltage, and a control current between the first control terminal H1 and the second control terminal H3 is formed. Under the condition of applying the electromagnetic field B, an induced current is generated between the first output terminal H2 and the second output terminal H4, so that a Hall voltage VH is generated between the first output terminal H2 and the second output terminal H4.

In this embodiment, the first control terminal H1 is connected to a power supply voltage VDD, and specifically, a first resistor R0 is connected in series between the first control terminal H1 and the power supply voltage VDD, so that the magnitude of the control current flowing through the hall element 110 is limited by the first resistor R0. The second control terminal H3 is grounded.

The hall element 110 is a hall plate, and specifically, the hall element 100 is a square hall plate. The first control terminal H1 and the second control terminal H3 are respectively located at two opposite top corners, and the first output terminal H2 and the second output terminal H4 are located at the other two opposite top corners. The direction of the current flow directly from H1 and H3 is 90 ° out of phase with the current flow between H2 and H4.

The comparing module 120 is connected to the first output terminal H2 and the second output terminal H4 of the hall element 110, and outputs a corresponding switch control signal VO according to the magnitude of the differential voltage Vin between the first output terminal H2 and the second output terminal H4. When the differential voltage Vin is 0, the switch control signal VO is inverted, i.e., changed from a high level to a low level, or from a low level to a high level.

The temperature compensation module 130 is configured to input a compensation current to the first output terminal H2, so that when a differential voltage Vin between the first output terminal H2 and the second output terminal H4 of the hall element 110 is 0, a corresponding magnetic field size is independent of a temperature coefficient of the hall element sensitivity. Under the condition that the temperature stability of other modules is higher, the sensitivity of the Hall sensor switch can also ensure higher stability.

Due to the input of the compensation current, the differential voltage Vin between the first output terminal H2 and the second output terminal H4 is obtained by subtracting the voltage generated by the compensation current at the first output terminal H2 from the hall voltage generated by the hall current. By inputting a proper compensation current to the hall element 110, the relationship between the magnetic field threshold value when the switching control signal VO is inverted and the temperature coefficient of the hall element 110 can be eliminated, thereby improving the stability of the sensitivity of the hall sensor switch. Specifically, the compensation current may be inversely proportional to a resistance, and the resistance has the same electron mobility as the hall element 110.

Fig. 4 is a schematic structural diagram of a hall sensor switch according to another embodiment of the present invention.

In this embodiment, the comparing module 120 includes a first amplifier AMP1 and a comparator COMP connected to an output terminal of the first amplifier AMP 1.

A positive input end of the first amplifier AMP1 is connected to the second output end H4 of the hall element 110, a negative input end is connected to the first output end H2 of the hall element 110, and output ends are connected to two input ends of the comparator COMP, so as to amplify the differential voltage Vin between the first output end H2 and the second output end H4 and output the amplified voltage Vin to the comparator COMP. And the comparator COMP outputs a corresponding switch control signal VO according to the input differential voltage.

The temperature compensation module 130 includes: a second resistor R1 connected in series between the power supply voltage VDD and a fixed potential terminal B, which has a fixed potential and is connected to the first output terminal H2 of the Hall element 110. The magnitude I of the compensation current outputted by the temperature compensation module 130 is VB/R1, which is inversely proportional to the resistance R1 of the second resistor R1. The second resistor R1 has the same electron mobility as the hall element 110 at the same temperature. Specifically, the second resistor R1 may be the same resistor type as the hall element 110. For example, the second resistor R1 and the hall element 110 are both square resistors.

The fixed potential terminal B may have a fixed potential by being connected to a constant voltage power supply or a clamp circuit. In this embodiment, the temperature compensation module 130 further comprises a clamp amplifier AMP2 for clamping the voltage at the fixed potential terminal B to a fixed value. Specifically, the positive input terminal of the clamp amplifier AMP2 is connected to the first control terminal H1 of the hall element 110, the negative input terminal is connected to the power supply voltage VDD through a second resistor R1 in series, and is connected to the first output terminal H2 of the hall element 110, i.e., the connection terminal a between the first resistor R0 and the hall element 110, and the output terminal of the clamp amplifier AMP2 is connected to the negative input terminal of the clamp amplifier AMP 2. The clamp amplifier AMP2 clamps the potential V of the negative input terminal, i.e., the fixed potential terminal B_BPotential V clamped to said connection terminal A_AI.e. V_A＝V_B. The Hall element 110 has an equivalent resistance value of R_H，

Then through a second resistor R1 to the first inputThe compensation current at the output end H2 is I₁，

Hall element 110 is equivalent to a Wheatstone bridge, and the resistance of each bridge arm is R_HA Hall voltage V is generated between the first output terminal H2 and the second output terminal H4 due to the magnetic field B_H,

Due to the compensation current I₁The first output terminal H2 and the second output terminal H4 input a differential voltage Vin to the input terminals of the first amplifier AMP1,

when V is_inWhen the value is equal to 0, equation (6) simplifies to obtain the magnitude of the flip point magnetic field of the comparator COMP:

and the second resistor R1 is a square resistor,

wherein q is a charge constant, n is an electron concentration, u_nFor electron mobility, w is the width of the resistor, L is the length of the resistor, and d is the thickness of the resistor.

Under constant pressure conditions (i.e. V)_AConstant case), the sensitivity of the hall element 110 can be expressed as:

wherein u is_nIs the electron mobility of the Hall element, and a second resistor R₁The mobility of (2) is the same. v is the charge movement speed, W 'is the width of the Hall element 110, and L' is the length of the Hall element 110. Due to R₁And u_nIn inverse ratio, K_HAnd u_nIn the formula (7), R is in direct proportion₁And K_HMultiplication, exactly canceling u_nThe influence of (c).

The magnitude of the flip-point magnetic field of the comparator COMP can be obtained by substituting equations (8) and (9) for equation (7):

as can be seen from equation (10), the temperature-dependent parameter of the trip point magnetic field B is only the resistance of the first resistor R0, and is not dependent on the temperature coefficient of the hall element 110. Even if the sensitivity of the hall element 110 changes due to the change in the electron mobility of the hall element 110 with the change in temperature, the magnitude of the trip point magnetic field B does not change following the change in the sensitivity of the hall element 110.

In order to reduce the influence of temperature change on the magnetic field B at the turning point as much as possible, the first resistor R0 may be a resistor with a small temperature coefficient, such as a low temperature drift resistor, including: foil resistance, thin film resistance, foil resistance, metal film resistance, and die resistance. The size of the magnetic field B at the turning point of the comparator COMP is smaller along with the change of the temperature, so that a stable magnetic field turning point can be obtained, and the stability of the Hall sensor switch is improved.

In this embodiment, a switching element is connected between the negative input terminal of the fixed potential terminal B and the first output terminal H2 of the hall element 110, and the output terminal of the clamp amplifier AMP2 is connected to the control terminal of the switching element. The above switching element is turned on only when the clamp amplifier AMP2 is in a normal operating state, so that the fixed potential terminal B is connected to the first output terminal H2. In this embodiment, the switch element is a PMOS transistor, the output terminal of the clamp amplifier is connected to the gate of the PMOS transistor, the source of the PMOS transistor is connected to the negative input terminal of the clamp amplifier AMP2, and the drain of the PMOS transistor is connected to the first output terminal H2 of the hall element 110.

In other embodiments, the potential of the fixed potential terminal B may also be limited to a fixed potential value by another clamp circuit, and the specific structure of the clamp circuit is not limited herein, and those skilled in the art can reasonably select the potential according to the requirements.

An embodiment of the present invention further provides an electronic device, including the hall sensor switch according to any one of the embodiments described above.

The above-mentioned embodiments are only examples of the present application, and not intended to limit the scope of the present application, and all equivalent structures or equivalent flow transformations made by the contents of the specification and the drawings, such as the combination of technical features between the embodiments and the direct or indirect application to other related technical fields, are also included in the scope of the present application.