JP2017207474A - Magnet sensor, motor assembly and application apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor integrated circuit, a motor assembly and an application apparatus.SOLUTION: A magnetic sensor, a motor and an application apparatus are provided. The magnetic sensor includes a magnetic sensing element, a chopping switch, a first discharging branch, and a second discharging branch. The magnetic sensing element includes a first terminal, a second terminal, a third terminal, and a fourth terminal. The first discharging branch is coupled between the first terminal and the third terminal. The second discharging branch is coupled between the second terminal and the fourth terminal. Before the first and third terminals serve as power input terminals and the second and fourth terminals serve as magnetic field detection signal output terminals, the second discharging branch is turned on; before the first and third terminals serve as the magnetic field detection signal output terminals and the second and fourth terminals serve as power input terminals, the first discharging branch is turned on.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to magnetic field detection, and more particularly to a magnetic sensor, a motor assembly, and an application device.

[0002] Magnetic sensors are widely applied in modern industrial and electronic products, and induce magnetic field strength to measure physical parameters such as current, position and direction. Motors are an important field of application for magnetic sensors. The magnetic sensor can serve as a position sensor for the rotor poles in the motor.

In general, a magnetic sensor can only output a magnetic field detection signal. However, the magnetic field detection signal is weak and mixed with the offset of the magnetic sensor, and it is difficult to obtain an accurate magnetic field detection signal.

In view of the above, a magnetic sensor integrated circuit, a motor assembly, and an application device are provided.

[0005] The magnetic sensor outputs a magnetic field detection signal, and includes a first terminal, a second terminal, a third terminal opposite to the first terminal, and a fourth terminal opposite to the second terminal. A first detector branch connected between the first terminal and the third terminal; a second discharge branch connected between the second terminal and the fourth terminal; The second discharge branch is turned on before the first terminal and the third terminal serve as power input terminals, and the second terminal and the fourth terminal serve as output terminals for the magnetic field detection signal, The first discharge branch is turned on before the first and third terminals serve as output terminals for the magnetic field detection signal and the second and fourth terminals serve as power input terminals.

[0006] Preferably, the magnetic field detection signal includes a magnetic field signal and an offset signal, and the magnetic sensor further includes a chopping switch for modulating the magnetic field signal and the offset signal to a high frequency region and a baseband frequency.

The first discharge branch includes a first discharge switch and a second discharge switch electrically connected in series, and the second discharge branch includes a third discharge switch and a second discharge switch electrically connected in series. Preferably, four discharge switches are provided.

[0008] The first discharge switch and the second discharge switch are respectively controlled by a first control signal and a second control signal, and the first control signal and the second control signal are two overlapping signals. When the first terminal and the third terminal serve as output terminals for the magnetic field signal, and the second terminal and the fourth terminal serve as power input terminals, the period in which the first control signal overlaps with the second control signal During this time, the third discharge switch and the fourth discharge switch are simultaneously turned on, the first terminal and the third terminal serve as power input terminals, and the second terminal and the fourth terminal are output terminals for the magnetic field signal. It is preferable that the first discharge switch and the second discharge switch are simultaneously turned on during a period in which the first control signal overlaps with the second control signal.

[0009] Preferably, the first control signal and the second control signal overlap at a high level.

[0010] Preferably, the magnet detection unit is driven by a constant current source, and a capacitor is connected between the constant current source and the ground terminal.

[0011] The first, second, third and fourth discharge switches are preferably MOS transistors.

[0012] The first control signal and the second control signal preferably have a frequency in a range from 100 KHz to 600 KHz.

[0013] The motor assembly includes a motor powered by an AC power source and a magnetic sensor.

[0014] The application apparatus includes a motor assembly, and the motor assembly includes a motor that is powered by an AC power source and a magnetic sensor.

[0015] To make the technical solutions according to the embodiments of the present disclosure or the prior art more apparent, the drawings according to the embodiments of the present disclosure will be briefly described below. Apparently, the drawings are only some embodiments of the present disclosure, and those skilled in the art can obtain other drawings from these drawings without creative work.

1 is a block diagram of a magnetic sensor according to one embodiment. FIG. FIG. 2 is a time series diagram of four control signals of the magnetic sensor of FIG. 1. It is the schematic of the control signal of the discharge switch and chopping switch of FIG. It is a block diagram of the magnetic sensor by another embodiment. 1 is a block diagram of a magnetic sensor integrated circuit according to one embodiment. FIG. 1 is a schematic structural diagram of a circuit of a motor assembly according to an embodiment of the present disclosure. 1 is a schematic structural diagram of a synchronous motor according to an embodiment of the present disclosure.

[0023] The technical solutions of the embodiments of the present disclosure are clearly and completely illustrated in conjunction with the drawings of the embodiments of the present disclosure. Apparently, the described embodiments are just a few rather than all of the embodiments of the present disclosure. Any other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative work shall fall within the scope of the present disclosure.

[0024] As described in the background section, in the conventional technology, generally, the magnetic sensor integrated circuit can output only the magnetic field detection result, and an additional peripheral circuit is required to process the magnetic field detection result. The Thus, the entire circuit is expensive and unreliable.

[0025] FIG. 1 shows a block diagram of a magnetic sensor according to one embodiment. The magnetic sensor 100 includes a magnet detection unit 10 that is a circuit diagram surrounded by a dotted line in FIG. The magnet detection unit 10 can include four contact terminals. The magnet detection unit 10 includes a first terminal A and a third terminal C arranged on the opposite side, and a second terminal B and a fourth terminal D arranged on the opposite side. In the embodiment, the magnet detection unit 10 can be a hole plate. The magnet detector 10 is driven by a power supply 16.

The magnetic sensor further includes a chopping switch 11. The chopping switch 11 includes eight switches K1 to K8, which are electrically connected to the four terminals and modulate the magnetic field detection signal output by the magnet detector 10. Specifically, the magnetic field detection signal includes a magnetic field signal and an offset signal, and the chopping switch 11 modulates the magnetic field signal and the offset signal to a chopping frequency and a baseband frequency, respectively.

As shown in FIG. 1, the chopping switch 11 includes eight switches K1 to K8. Specifically, the chopping switch 11 includes a first switch K1, a second switch K2, a third switch K3, a fourth switch K4, a fifth switch K5, a sixth switch K6, and a seventh switch. K7 and an eighth switch K8. The first switch K1 is connected between the power supply 16 and the first terminal A. The second switch K2 is connected between the power supply 16 and the second terminal B. The third switch K3 is connected between the ground terminal GND and the third terminal C. The fourth switch K4 is connected between the ground terminal GND and the fourth terminal D. The fifth switch K5 is connected between the first output terminal P and the fourth terminal D. The sixth switch K6 is connected between the first output terminal P and the third terminal C. The seventh switch K7 is connected between the second output terminal N and the second terminal B. The eighth switch K8 is connected between the second output terminal N and the first terminal A.

The first clock signal includes a first sub clock signal CK2B, a second sub clock signal CK1B, a third clock signal CK2, and a fourth sub clock signal CK1. The first switch K1 and the second switch K2 are controlled by the first sub clock signal CK2B and the second sub clock signal CK1B, respectively. The third switch K3 and the fourth switch K4 are controlled by the third sub clock signal CK2 and the fourth sub clock signal CK1, respectively. The fifth switch K5 and the sixth switch K6 are controlled by the third sub clock signal CK2 and the fourth sub clock signal CK1, respectively. The seventh switch K7 and the eighth switch K8 are controlled by the third sub clock signal CK2 and the fourth sub clock signal CK1, respectively.

[0029] To ensure the accuracy of the output signal, the first clock signal includes at least two non-overlapping sub-clock signals. The phase of the first sub clock signal CK2B is opposite to the phase of the third sub clock signal CK2, and the phase of the second sub clock signal CK1B is opposite to the phase of the fourth sub clock signal CK1. The third sub clock signal CK2 and the fourth sub clock signal CK1 are non-overlapping sub clock signals.

[0030] When the first terminal A is electrically connected to the power supply 16 and the third terminal C is electrically connected to the ground terminal GND, the second terminal B is electrically connected to the second output terminal N; The fourth terminal D is electrically connected to the first output terminal P. When the second terminal B is electrically connected to the power source 16 and the fourth terminal D is electrically connected to the ground terminal GND, the first terminal A is electrically connected to the second output terminal N, and the third terminal The terminal C is electrically connected to the first output terminal P. The first output terminal P outputs the difference signal P1, and the second output terminal N outputs the difference signal N1.

In addition to the magnetic sensor and the first chopping switch 11 described, the magnetic sensor includes a first discharge branch 12 connected between the first terminal A and the third terminal C, ie, the first And a second discharge branch 13 connected between the second terminal B and the fourth terminal D, that is, the second terminal B and the fourth terminal. And a branch with respect to the terminal D. The second discharge branch 13 is turned on before the first terminal A and the third terminal C serve as power input terminals and the second terminal B and the fourth terminal D serve as output terminals for the magnetic field detection signal. . The first terminal A and the third terminal C serve as output terminals for magnetic field detection signals, and the second terminal B and the fourth terminal D serve as power input terminals before the power input terminal, the first discharge branch 13. Turns on.

[0032] In the embodiment, the first discharge branch 12 may include a first discharge switch S1 and a second discharge switch S2 connected in series. The first discharge switch S1 and the second discharge switch S2 are controlled by the first sub clock signal CK2B and the second sub clock signal CK1B, respectively. The second discharge branch 13 includes a third discharge switch S3 and a fourth discharge switch S4 connected in series. The third discharge switch S3 and the fourth discharge switch S4 are controlled by the first sub clock signal CK2B and the second sub clock signal CK1B, respectively.

[0033] When the first terminal A and the third terminal C serve as power input terminals, and the second terminal B and the fourth terminal D serve as output terminals for magnetic field signals, the first sub-clock signal CK2B is During a period overlapping with the second sub clock signal CK1B, the first discharge switch S1 and the second discharge switch S2 are simultaneously turned on. When the first terminal A and the third terminal C serve as output terminals for the magnetic field signal, and the second terminal B and the fourth terminal D serve as power input terminals, the first sub-clock signal CK2B is During the period overlapping with the sub clock signal CK1B, the third discharge switch S3 and the fourth discharge switch S4 are simultaneously turned on.

As shown in FIG. 2, the four sub-clock signals include two non-overlapping control signals, that is, a third sub-clock signal CK1 and a fourth sub-clock signal CK2, and two overlapping signals, that is, a second sub-clock signal. The sub clock signal CK1B and the first sub clock signal CK2B. CK1 is opposite to CK1B and CK2 is opposite to CK2B. Overlapping subclock signals CK1B and CK2B are both at a high level during the period when CK1B and CK2B overlap, that is, during the period between the two dotted lines shown in FIG. The two non-overlapping subclock signals CK1 and CK2 and the two overlapping subclock signals CK1B and CK2B can have a frequency ranging from 100 KHz to 600 Hz including both ends, and the frequency is preferably 400 KHz.

FIG. 3 is a schematic diagram of a control signal for the chopping signal of the discharge switch. In the embodiment of the present disclosure, each of the eight switches included in the chopping switch 11 and the four discharge switches included in the discharge branch may be a transistor. Furthermore, when CK1 is high, CK2B is high and CK2 and CK1B are low. In such a case, the second terminal B and the fourth terminal D are electrically connected to the power supply 16 and the ground terminal GND, respectively, to serve as power input terminals, and the third terminal C and the first output terminal P. The switch between the first terminal A and the second output terminal N is turned on, and the first terminal A and the third terminal C serve as output terminals for the magnetic field signal. A short time immediately after CK1 shifts from the high level to the low level, that is, the time between the first two dotted lines shown in FIG. 2 is the overlapping period of the two overlapping subclock signals CK1B and CK2B. During the overlap period, both CK1B and CK2B are at a high level, and the third discharge switch S3 and the fourth discharge switch S4 between the second terminal B and the fourth terminal D are simultaneously turned on and The second terminal B is short-circuited with the fourth terminal D, thereby removing the charge stored in the parasitic capacitor between the second terminal B and the fourth terminal D. After the overlap period, when CK1 is low, CK2B is low and CK2 and CK1B are high. In this case, the first terminal A and the third terminal C are electrically connected to the first power and the ground terminal GND, respectively, to serve as power input terminals, and the second terminal B and the first output terminal P Is switched on, the switch between the fourth terminal D and the second output terminal N is turned on, and the second terminal B and the fourth terminal D serve as output terminals for the magnetic field signal. . A short time immediately before CK1 shifts from the low level to the high level, that is, the time between the second two dotted lines shown in FIG. 2 is the overlapping period of the two sub clock signals CK1B and CK2B. During this period, both CK1B and CK2B are at a high level, and the first discharge switch S1 and the second discharge switch S2 between the first terminal A and the third terminal C are turned on and the first discharge switch S2 is turned on. Terminal A is short-circuited with the third terminal C, thereby removing the charge stored in the parasitic capacitor between the first terminal A and the third terminal C.

In the embodiment, the first switch K1 and the second switch K2 are PMOS transistors, and the third switch K3 and the fourth switch K4 are NMOS transistors.

[0037] FIG. 4 shows a magnetic sensor according to another embodiment. The magnetic sensor of FIG. 4 is similar to the magnetic sensor of FIG. 1 except that the magnetic sensor further includes a capacitor 14 connected between a power supply 16 and a ground terminal (common terminal).

[0038] In an embodiment, the power source 16 may be a constant voltage source or a constant current source. When the magnet detector 10 is driven by a constant current source, the detection sensitivity of the magnetic sensor does not change with temperature.

In an embodiment, the capacitor 14 can supply a constant voltage. When switching between input / output terminals, the capacitor 14 can pull up the voltage at the input terminal to ensure good performance of the magnetic sensor.

In the embodiment, the capacitance of the capacitor 14 can be several tens of picofarads (pF), and the capacitance of the capacitor 14 is larger than the capacitance of the parasitic capacitor between the contact terminals.

[0041] In the embodiment, the capacitor 14 may be a MOS capacitor.

[0042] FIG. 5 shows a block diagram of a magnetic sensor integrated circuit 4000 according to an embodiment. The magnetic sensor integrated circuit 4000 is electrically connected to an AC power source, and outputs a control signal to a triac (TRIAC) according to the polarity of the magnetic field. The magnetic sensor integrated circuit 4000 includes a rectifier 400, a current source generator 300, a magnetic sensor 100, and a clock module 200. The rectifier 400 can convert external power into direct current (DC) power to the magnetic sensor and watch module. The current source generator 300 can output a plurality of currents having different values according to the DC power. A magnetic sensor 100 as shown in FIG. 1 can detect the polarity of an external magnetic field and output a control signal. The timepiece module 200 can output a plurality of clock signals to the magnetic sensor.

[0043] As shown in FIG. 6, an embodiment of the present disclosure further provides a motor assembly. The motor assembly includes a motor 2000 powered by an AC power supply 1000, a bidirectional conductive switch 3000 connected in series to the motor 2000, and a magnetic sensor integrated circuit 4000 according to any one of the above embodiments of the present disclosure. . The output port of the magnetic sensor integrated circuit 4000 is electrically connected to the control end of the bidirectional conductive switch 3000. Bi-directional conductive switch 3000 is preferably triac (TRIAC). It should be understood that the bidirectional conductive switch can be implemented as other suitable types of switches. For example, a bidirectional conductive switch can include two silicon controlled rectifiers connected in anti-parallel and a corresponding control circuit. The two silicon controlled rectifiers are controlled in a predetermined manner by the control circuit based on the output signal output from the output port of the magnetic sensor integrated circuit.

The motor preferably further includes a voltage drop circuit 5000 for reducing the voltage of the AC power supply 1000 and supplying the drop voltage to the magnetic sensor integrated circuit 4000. The magnetic sensor integrated circuit 4000 is disposed near the rotor of the motor 2000 and detects a change in the magnetic field of the rotor.

[0045] Based on the above embodiment, in the embodiment of the present disclosure, the motor is a synchronous motor. It should be understood that the magnetic sensor integrated circuit according to the present disclosure applies not only to synchronous motors, but also to other types of permanent magnet motors such as DC brushless motors. As shown in FIG. 7, the synchronous motor includes a stator and a rotor 1001 that rotates with respect to the stator. The stator includes a stator core 1002 and a stator winding 1006 wound around the stator core 1002. The stator core 1002 can be made of a soft magnetic material such as pure iron, cast iron, cast steel, electric steel, or silicon steel. The rotor 1001 includes a permanent magnet. When the stator winding 1006 is connected in series with an AC power source, the rotor 1001 rotates at a constant speed (60 f / p) rotation / minute, where f is the frequency of the AC power source, p is the number of pole pairs of the rotor. In the embodiment, the stator core 1002 has two pole portions 1004 arranged to face each other. Each pole portion has a pole arc surface 1005. The outer surface of the rotor 1001 faces the magnetic pole arc surface, and a substantially uniform air gap is formed between them. Basically uniform air gaps in this disclosure indicate that the majority of the air gap between the stator and the rotor is uniform and the small part of the air gap between the stator and the rotor is non-uniform. . A concave starting groove 1007 is preferably disposed on the magnetic pole arc surface 1005 of the pole portion of the rotor. Portions other than the starting groove 1007 on the magnetic pole arc surface 1005 are concentric with the rotor. With the above configuration, a non-uniform magnetic field can be formed, whereby the rotor polar axis S1 forms an angle with respect to the central axis S2 of the stator pole portion when the rotor is not rotating. Since it is guaranteed to tilt, the rotor can have a starting torque each time the motor is powered under the action of the integrated circuit. The rotor polar axis S1 is a boundary between two magnetic poles of the rotor having different polarities. The central axis S2 of the stator pole portion 1004 is a connecting line passing through the centers of the two pole portions 1004 of the stator. In an embodiment, the stator and the rotor each have two magnetic poles. In other embodiments, the number of magnetic poles of the stator can be different from the number of magnetic poles of the rotor, and the stator and rotor can have more magnetic poles, for example, 4 magnetic poles and 6 magnetic poles. Please understand that.

[0046] Accordingly, an application apparatus according to an embodiment of the present disclosure is further provided. The application apparatus includes a motor fed by an AC power source, a bidirectional conductive switch electrically connected in series with the motor, and a magnetic sensor integrated circuit according to any one of the above embodiments. The output port of the magnetic sensor integrated circuit is electrically connected to the control end of the bidirectional conductive switch. Optionally, the application device can be a pump, a fan, a home appliance, a vehicle and the like, such as a washing machine, a dishwasher, a range hood, an exhaust fan, etc.

[0047] Following the description of the embodiments herein, one of ordinary skill in the art will be able to make or use the disclosure. Many improvements to the embodiments will be apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the disclosure. Accordingly, the present disclosure is not limited to the embodiments described herein, but is to be accorded with the widest scope consistent with the principles and novel features disclosed herein.

DESCRIPTION OF SYMBOLS 10 Magnetic detection part 11 Chopping switch A, B, C, D Terminal K1 to K8 Switch 14 1st discharge branch 15 2nd discharge branch 16 Power supply P, N Output terminal GND Ground

Claims (10)

A magnetic sensor,
A magnet detection unit that outputs a magnetic field detection signal and has a first terminal, a second terminal, a third terminal opposite to the first terminal, and a fourth terminal opposite to the second terminal When,
A first discharge branch connected between the first terminal and the third terminal;
A second discharge branch connected between the second terminal and the fourth terminal,
Before the first terminal and the third terminal serve as power input terminals, and the second terminal and the fourth terminal serve as magnetic field detection signal output terminals, the second discharge branch is turned on, The first discharge branch is turned on before the first terminal and the third terminal serve as magnetic field detection signal output terminals, and the second terminal and the fourth terminal serve as power input terminals; Magnetic sensor characterized by.   The magnetic sensor according to claim 1, wherein the magnetic field detection signal includes a magnetic field signal and an offset signal, and the magnetic sensor further includes a chopping switch for modulating the magnetic field signal and the offset signal to a high frequency region and a baseband frequency. .   The first discharge branch includes a first discharge switch and a second discharge switch that are electrically connected in series, and the second discharge branch includes a third discharge switch and a fourth discharge switch that are electrically connected in series. The magnetic sensor according to claim 1, comprising: a discharge switch.   The first discharge switch and the second discharge switch are controlled by a first control signal and a second control signal, respectively, and the first control signal and the second control signal are two overlapping signals. Yes, when the first terminal and the third terminal serve as output terminals for the magnetic field signal, and the second terminal and the fourth terminal serve as power input terminals, the first control signal is During a period overlapping with the second control signal, the third discharge switch and the fourth discharge switch are simultaneously turned on, the first terminal and the third terminal serve as power input terminals, and the second When the first terminal and the fourth terminal serve as magnetic field signal output terminals, the first discharge switch and the second discharge switch during a period in which the first control signal overlaps the second control signal. Is the same It turned on, the magnetic sensor according to claim 3.   The magnetic sensor of claim 4, wherein the first control signal and the second control signal overlap at a high level.   The magnetic sensor according to claim 1, wherein the magnet detection unit is driven by a constant current source, and a capacitor is connected between the constant current source and a ground terminal.   The magnetic sensor according to claim 4, wherein the first, second, third, and fourth discharge switches are MOS transistors.   The magnetic sensor according to claim 4, wherein the first control signal and the second control signal have a frequency in a range from 100 KHz to 600 KHz.   A motor assembly comprising: a motor fed by an AC power supply; and the magnetic sensor according to claim 1.   It is an application apparatus provided with a motor assembly, Comprising: The said motor assembly is provided with the motor electrically fed by alternating current power supply, and the said magnetic sensor as described in any one of Claims 1-8. Application equipment.

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