JP3209066U - Magnetic sensor and integrated circuit - Google Patents

Abstract

A magnetic sensor capable of controlling the operation of an electric rotor by generating an accurate signal with respect to the polarity of an external magnetic field. The present invention relates to a magnetic sensor including an input port, a magnetic field detection circuit for generating a magnet detection signal, an output control circuit for controlling the operation of the magnetic sensor, and an output port. The magnetic field detection circuit includes a magnetic detection element (Hall detector) that detects an external magnetic field and outputs a detection signal, a signal processing element configured to amplify the detection signal and remove interference from the detection signal, An analog-to-digital conversion element 1430 configured to convert the detected signal into a magnet detection signal, wherein the output control circuit is at least one of the first state and the second state in response to at least the magnet detection signal And the signal processing element includes a folded cascode amplifier. [Selection] Figure 4

Description

  The present teachings relate to the field of circuit technology. Specifically, the present teachings relate to magnetic sensors. Furthermore, the present teachings also relate to drivers for permanent magnet motors.

  In modern industry and electronic products, magnetic sensors are widely applied to induce magnetic field strength and 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 rotor pole position sensor in the motor.

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

  The present teachings provide a magnetic sensor and its applications. According to embodiments of the present teachings, a magnetic sensor includes an input port connected to an external power source, a magnetic field detection circuit configured to generate a magnet detection signal, and operation of the magnetic sensor in response to the magnet detection signal An output control circuit configured to control an output port, and a magnetic field detection circuit configured to detect an external magnetic field and output a detection signal; and amplifying the detection signal Magnet detection including a signal processing element configured to remove interference from the detection signal and generate a processed detection signal; and a conversion element configured to convert the processed detection signal into a magnet detection signal The signal is used to control the magnetic sensor to operate in at least one of the first state and the second state in response to at least the magnet detection signal, and in the first state, the magnetic signal is output from the output port. Capacitors external to the load current flows, and in the second state, the load current flows through the output port of the magnetic sensor from the outside, signal processing element includes a folded cascode amplifier.

  In some embodiments, the detection signal includes a magnetic field signal and a deviation signal, and the signal processing element is configured to separate the detection signal into a deviation signal and a magnetic field signal corresponding to a chopper frequency and a baseband frequency, respectively. A first chopper switch, a chopper amplifier configured to amplify the deviation signal and the magnetic field signal, and switch the amplified deviation signal and the amplified magnetic field signal to a chopper frequency and a baseband frequency, respectively, and a chopper frequency And a filter circuit configured to filter out the deviation signal.

  In some embodiments, the chopper amplifier includes a first amplifier and a second chopper switch, wherein the first amplifier is a first stage for the deviation signal and the magnetic field signal from the first chopper switch. And a folded cascode amplifier configured to generate an amplified deviation signal and an amplified magnetic field signal, respectively, and the second chopper switch includes the amplified deviation signal and the amplified magnetic field signal. It is configured to switch to a chopper frequency and a baseband frequency, respectively.

  In some embodiments, the chopper frequency is higher than 100 Khertz and the baseband frequency is lower than 200 Hertz.

  In some embodiments, the chopper amplifier further includes a second amplifier connected in series with a second chopper switch, the second amplifier comprising an amplified deviation signal switched to the chopper frequency, and a base The second stage amplification is performed on the amplified magnetic field signal switched to the band frequency.

  In some embodiments, the signal processing element further includes a sample and hold circuit coupled between the chopper amplifier and the filter circuit, wherein the sample and hold circuit transfers the first differential signal pair during the first half of the clock cycle and Each is sampled during the second half and is configured to output two sampled differential signal pairs during the clock cycle.

  In some embodiments, the filter circuit includes a first filter configured to calculate a second differential signal pair based on the two sampled differential signal pairs.

  In some embodiments, the filter circuit further includes a second filter configured to further amplify the second differential signal pair and remove the deviation signal to generate a third differential signal pair. Including.

  In some embodiments, the magnetic sensor further includes a rectifier circuit coupled to the input port and configured to provide a voltage source to the magnetic field detection circuit.

  In some embodiments, the external power source is an alternating current (AC) power source, the magnet detection signal is a switching detection signal, and the switching frequency of the magnetic detection signal is proportional to the frequency of the AC power source or of the frequency of the AC power source. 2 times.

  In some embodiments, the magnetic sensor further comprises an output control circuit configured to control the magnetic sensor to operate based on the magnet detection signal in at least one of the first state and the second state; The output control circuit is coupled to the output port and forms a first current path that allows a load current to flow from the output port to the outside of the magnetic sensor. The output control circuit is coupled to the output port and connected to the outside of the magnetic sensor. And a second switch that forms a second current path through which a load current can flow from the output port to the output port. The first and second switches pass the first and second current paths based on the magnet detection signal. Operate selectively.

  In some embodiments, the first switch is a transistor and the second switch is either a diode or a transistor.

  According to another embodiment of the present teachings, an integrated circuit for a magnetic sensor comprises an input port connected to an external power source, an output port, and a magnetic field detection circuit configured to generate a magnet detection signal, The magnetic field detection circuit detects an external magnetic field and outputs a detection signal including a magnetic field signal and a deviation signal. The magnetic detection element amplifies the detection signal, removes interference, and processes the processed detection signal. A signal processing element configured to generate and a conversion element configured to convert the processed detection signal into a magnet detection signal, wherein the magnet detection signal is responsive to at least the magnet detection signal from the magnetic sensor. The signal processing element is used to control to operate in at least one of the first state and the second state, and the signal processing element has a magnetic field corresponding to the chopper frequency and the baseband frequency, respectively. A first chopper switch configured to separate the signal and the deviation signal, and the magnetic field signal and the deviation signal are separately amplified, and the amplified deviation signal and the amplified magnetic field signal are converted to a chopper frequency and a baseband frequency. Each includes a chopper amplifier configured to switch and a filter circuit configured to remove a deviation signal switched to the chopper frequency, and the signal processing element includes a folded cascode amplifier.

  According to another embodiment of the present teachings, a motor assembly is coupled to an external power source that provides alternating current (AC) power, a magnetic sensor configured to detect a magnetic field generated by the motor, and a detection A bidirectional switch configured to control the motor based on the operating state of the magnetic sensor determined based on the magnetic field, the magnetic sensor detects the magnetic field, and detects the magnet based on the detected magnetic field A magnetic field detection circuit configured to generate a signal, the magnetic field detection circuit configured to detect an external magnetic field and output a detection signal; and a magnetic detection element that amplifies the detection signal and Magnet detection including a signal processing element configured to remove interference and generate a processed detection signal and a conversion element configured to convert the processed detection signal into a magnet detection signal Is used to control the magnetic sensor to operate at least one of the first state and the second state in response to at least a magnet detection signal, the magnetic sensor at least in response to the magnet detection signal. An output control circuit configured to control the magnetic sensor to operate in at least one of the first state and the second state, and in the first state, current flows from the outside of the magnetic sensor into the magnetic sensor. In the second state, current flows from the magnetic sensor to the outside of the magnetic sensor, and the signal processing element includes a folded cascode amplifier.

  The methods, systems and / or programs described herein are further described in terms of exemplary embodiments. These exemplary embodiments will be described in detail with reference to the drawings. These embodiments are non-limiting exemplary embodiments in which like structures are indicated by like reference numerals throughout the several views of the drawings.

2 is an exemplary schematic diagram of a magnetic sensor according to an embodiment of the present teachings. FIG. FIG. 11 is an exemplary schematic diagram of a signal processing element 1110 according to an embodiment of the present teachings. 2 is an exemplary schematic diagram of a chopper amplifier 1204 according to an embodiment of the present teachings. FIG. FIG. 6 is an exemplary schematic diagram of a chopper amplifier 1204 according to another embodiment of the present teachings. 2 is an exemplary schematic diagram of a magnetic sensor according to an embodiment of the present teachings. FIG. FIG. 4 is an exemplary schematic diagram of a rectifier circuit 1402 according to an embodiment of the present teachings. FIG. 4 is an exemplary circuit diagram of a Hall detector 1420 and a first chopper switch according to an embodiment of the present teachings. FIG. 7 illustrates an exemplary signal output according to the circuit diagram of FIG. FIG. 4 is an exemplary circuit diagram of a filter circuit 1428 according to an embodiment of the present teachings. FIG. 4 is an exemplary circuit diagram of a comparison circuit 1430 according to an embodiment of the present teachings. FIG. 3 is an exemplary schematic diagram for determining the polarity of a magnetic field. FIG. 6 illustrates an exemplary signal output in a clock cycle. FIG. 4 is an exemplary circuit diagram of an output control circuit 1406 according to an embodiment of the present teachings. FIG. 4 is an exemplary circuit diagram of an output control circuit according to another embodiment of the present teachings. FIG. 6 is an exemplary circuit diagram of an output control circuit according to yet another embodiment of the present teachings. FIG. 3 is an exemplary schematic diagram of a motor 2500 incorporating a magnetic sensor constructed in accordance with the present teachings. FIG. 5 is an exemplary schematic diagram of a synchronous motor 2600 incorporating a magnetic sensor constructed in accordance with the present teachings.

  In the following detailed description, numerous specific details are set forth by way of example in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well-known methods, procedures, systems, components, and / or circuits have been described at a relatively high level without details so as not to unnecessarily obscure aspects of the present teachings.

  Terms in the specification and claims can have subtly different meanings suggested or implied in context, in addition to the meanings specified. Similarly, the expression “in one embodiment / example” as used herein does not necessarily refer to the same embodiment, but the expression “in another embodiment / example” as used herein. Does not necessarily refer to different embodiments. For example, the subject matter recited in the claims is intended to include a full or partial combination of the exemplary embodiments.

  In general, terminology can be at least partially understood from its use in context. For example, terms such as “and”, “or”, “and / or” as used herein have various meanings that can depend at least in part on the context in which such terms are used. it can. Usually, the term “or” when used to associate lists, such as A, B or C, A, B and C in a comprehensive sense, and A, B in an exclusive sense, Or is intended to mean C. Also, as used herein, the term “one or more” may be used in the singular form to denote any feature, structure, or characteristic, depending at least in part on the context, Alternatively, it may be used in the plural sense to indicate a combination of features, structures or properties. Similarly, terms such as “a (English indefinite article)” and “its (English definite article)” also convey the use of the singular or plural, depending at least in part on the context. I can understand. Also, the term “based on” is not necessarily intended to convey an exclusive set of factors, and it is understood that there may be additional factors that are not necessarily specified. Can do.

  The magnetic sensor in the present teaching uses at least one folded cascode amplifier. The folded cascode amplifier can efficiently amplify a minute input signal and have a large gain. In addition, the folded cascode amplifier is configured to have excellent frequency characteristics, and can process a signal extending in an ultra-wide frequency range. Furthermore, the magnetic sensors of the present teachings can be directly connected to a city AC power source without the need for additional A / D conversion facilities. Thus, the present teachings facilitate the mounting of magnetic sensors in various fields. Furthermore, the magnetic field detection circuit can effectively amplify the detected magnetic field signal, adjust the voltage, and filter the interference signal. Thus, the magnetic sensor can control the operation of the electric rotor by generating an accurate signal with respect to the polarity of the external magnetic field.

  Additional novel features, which are set forth in part in the following description, will be, in part, apparent to those skilled in the art upon review of the accompanying drawings, or may be learned by example manufacturing or operation. The novel features of the present teachings can be realized or attained by implementing or using various aspects of the methods, means, and combinations thereof as set forth in the detailed examples below. A magnetic sensor, a signal processing method mounted on the magnetic sensor, and a motor using these magnetic sensor and signal processing method disclosed below in the present specification are not limited, but include an integrated circuit and other circuits. Can be achieved using any circuit technique known to those skilled in the art.

  FIG. 1 is an exemplary schematic diagram of a magnetic sensor according to an embodiment of the present teachings. The magnetic sensor according to this embodiment includes an input port 1102, a magnetic field detection circuit 1104, and an output port 1106. The input port 1102 is connected to an external power source and configured to supply power to the magnetic field detection circuit 1104. In some embodiments, the external power source is a direct current (DC) power source. In another embodiment, the external power source is an alternating current (AC) power source. The magnetic field detection circuit 1104 is configured to detect an external magnetic field and generate a magnetic field detection signal. The magnetic field detection signal 1106 is applied so as to control the operation state of a magnetic sensor and a motor, or any electric equipment using the magnetic sensor.

  The magnetic field detection circuit 1104 can include a magnetic sensing element 1108, a signal processing element 1110, and a conversion element 1114. The magnetic sensing element 1108 is configured to sense an external magnetic field and output a first detection signal 1120. The first detection signal 1120 output from the magnetic sensing element 1108 includes at least a magnetic field signal and a deviation signal. The magnetic field signal indicates the actual magnetic voltage signal associated with the external magnetic field detected by the magnetic sensing element 1108. The deviation signal is a bias signal that is inherited within the magnetic sensing element 1108.

  Since the actual magnetic voltage signal may be interfered with at least by the inherited bias signal, the signal processing element 1110 amplifies the received first detection signal 1120 and generates an interference signal from the first detection signal 1120. The second detection signal 1122 is configured to be removed. In some embodiments, the signal processing element 1110 can include at least one folded cascode amplifier 1112.

  The conversion element 1114 is configured to convert the second detection signal 1122 into a magnetic field detection signal and output the magnetic field detection signal via the output port 1106. In some embodiments, the magnetic field detection signal is a switching detection signal.

  FIG. 2 is an exemplary schematic diagram of a signal processing element 1110 according to an embodiment of the present teachings. The signal processing element 1110 according to FIG. 1 includes a first chopper switch (Z1) 1202 and a first chopper amplifier (IA) 1204. The first chopper switch 1202 is configured to separate the deviation signal and the magnetic field signal carried at the baseband frequency and the chopper frequency, respectively. The first chopper amplifier 1204 is configured to amplify the deviation signal and the magnetic field signal, and transmit the amplified deviation signal and the magnetic field signal by switching to the chopper frequency and the baseband frequency, respectively. In some embodiments, the chopper frequency is higher than 100 KHz and the baseband frequency is lower than 200 Hz.

  In some embodiments, when the external power source is an AC power source, the baseband frequency is proportional to the frequency of the AC power source. In some embodiments, the baseband frequency is twice the frequency of the AC power source.

  In some embodiments, the signal processing element 1110 can further include a low pass filter (LPF) 1206 configured to remove the deviation signal transmitted via the chopper frequency.

  In this embodiment, each of the input and output of the first chopper switch (Z1) 1202, the first chopper amplifier (IA) 1204, and the low-pass filter (LPF) 1206 is shown by a single line. It should be understood that FIG. 2 is for illustrative purposes. The present teachings are not intended to be limiting. Each of the inputs and outputs of the first chopper switch (Z1) 1202, the first chopper amplifier (IA) 1204, and the low-pass filter (LPF) 1206 can be one or more input / output signals. . In some embodiments, each of the inputs and outputs of the first chopper switch (Z1) 1202, the first chopper amplifier (IA) 1204, and the low pass filter (LPF) 1206 has one or more pairs. Includes differential signals.

  FIG. 3A is an exemplary schematic diagram of a chopper amplifier 1204 according to an embodiment of the present teachings. The first chopper amplifier (IA) 1204 in FIG. 2 includes a first amplifier (A1) 1302 and a second chopper switch (Z2) 1304. The first amplifier (A1) 1302 is configured to amplify the first stage of the deviation signal and the magnetic field signal from the first chopper switch (Z1) 1202. In some embodiments, the first amplifier (A1) 1302 is implemented with at least one folded cascode amplifier, such as 1112. The second chopper switch (Z2) 1304 is configured to switch and transmit the amplified deviation signal and magnetic field signal to the chopper frequency and the baseband frequency, respectively.

  FIG. 3B is an exemplary schematic diagram of a chopper amplifier 1204 according to another embodiment of the present teachings. According to the illustrated embodiment, the first chopper amplifier (IA) 1204 of FIG. 2 includes a second amplifier (A2) in addition to the first amplifier (A1) 1302 and the second chopper switch (Z2) 1304. 1306. The second amplifier (A2) 1306 is configured to further amplify the second stage of the deviation signal and magnetic field signal from the second chopper switch (Z2) 1304. In some embodiments, a second chopper switch (Z2) 1304 is implemented based on a single stage amplifier.

  It should be understood that the connections of the first amplifier (A1) 1302, the second chopper switch (Z2) 1304, and the second amplifier (A2) 1306 in FIG. 3B are for illustrative purposes. The present teachings are not intended to be limiting. In some embodiments, the second amplifier (A2) 1306 may be disposed between the first amplifier (A1) 1302 and the second chopper switch (Z2) 1304.

  FIG. 4 is an exemplary schematic diagram of a magnetic sensor according to another embodiment of the present teachings. The magnetic sensor according to this exemplary embodiment includes an input port 1408, a rectifier circuit 1402, a magnetic field detection circuit 1404, an output control circuit 1406, and an output port 1410. The input port 1408 of this embodiment includes a pair of input ports 1408A and 1408B that connect to an external power source. In some embodiments, the input port 1408 can be connected in series with an external power source. In still other embodiments, the input port 1408 can be connected in parallel to an external power source.

  The rectifier circuit 1402 can be implemented based on a full wave rectifier bridge and a voltage regulator (not shown). The full wave rectifier bridge can be configured to convert an AC signal from an AC power source into a DC signal. The voltage regulator can be configured to regulate the DC signal within a preset range. The rectifier circuit 1402 supplies the adjusted DC signal to the magnetic field detection circuit 1404 and the output control circuit 1406.

  In the illustrated embodiment, the magnetic field detection circuit 1404 includes a Hall detector 1420, a first chopper switch 1422, a first chopper amplifier 1424, a sample and hold circuit 1426, a filter circuit 1428, and a comparison circuit 1430. including. The Hall detector 1420 is connected to the rectifier circuit 1402 to detect a magnetic field signal, and outputs the detected magnetic field signal to the first chopper switch 1422. The first chopper switch 1422 is configured to perform the same function as the first chopper switch 1202 shown in FIG. The first chopper switch 1422 outputs the first differential signal pair {P1, N1} to the first chopper amplifier 1424.

  The first chopper amplifier 1424 can be implemented based on the first chopper amplifier shown in FIG. 3B. Accordingly, the first chopper amplifier 1424 includes a first amplifier (A1) 1302, a second chopper switch (Z2) 1304, and a second amplifier (A2) 1306. The first amplifier (A1) 1302 performs first-stage amplification of the received first differential signal pair {P1, N1}. The second chopper switch (Z2) 1304 directly outputs the amplified differential signal {P1, N1} in the first half of the clock cycle, and switches and outputs the amplified differential signal {P1, N1} in the second half of the clock cycle. Configured. The second chopper switch (Z2) 1304 outputs the second differential signal pair {P2, N2}. The second differential signal pair {P 2, N 2} can be further amplified by the second amplifier (A 2) 1306 and then output to the sample and hold circuit 1426.

  The sample and hold circuit 1426 is configured to sample the second amplified differential signal pair {P2, N2} output from the first chopper amplifier 1424 of FIG. 4 during the first half and the second half of the clock cycle, respectively. . The output of the sample and hold circuit 1426 includes two differential signal pairs {P2A, N2A} and {P2B, N2B}, where the {P2A, N2A} pair is output during the first half of the clock cycle and {P2B, N2B} Are output during the second half of the clock cycle.

  The filter circuit 1428 removes the deviation signal from the two differential signal pairs {P2A, N2A} and {P2B, N2B}, amplifies the differential signals {P2A, N2A} and {P2B, N2B}, and compares them. The third differential signal {P3, N3} is output to 1430.

  The comparison circuit 1430 is configured to compare the third differential signal pair {P3, N3} with the reference voltage signal pair and determine the polarity of the external magnetic field based on the comparison result. The comparison circuit 1430 generates a magnetic field detection signal indicating the determined polarity of the external magnetic field and outputs it to the output control circuit 1406. In some embodiments, the magnetic field detection signal is a switching magnetic field detection signal.

  The output control circuit 1406 is configured to control the magnetic sensor to operate in a state according to the determined polarity of the external magnetic field. The magnetic sensor can operate in multiple states. For example, the first state can correspond to a scenario in which a load current flows from the inside of the magnetic sensor to the outside via the output port 1410, and the second state is from the outside of the magnetic sensor via the output port 1410. It can cope with a scenario in which a load current flows inside. In some embodiments, the magnetic sensor may operate in a third state in which no current flows through the output port 1410.

  Usually, the actual magnetic voltage signal is very small. For example, it is generally less than 1 millivolt. However, the deviation signal produced by the Hall detector 1420 is often higher, for example about 10 millivolts. The present teachings provide an operational level of an actual magnetic voltage signal to a motor or any electrical installation that uses a magnetic sensor by removing the deviation signal and amplifying the actual magnetic voltage signal. With the goal. In some embodiments, the voltage supply to the magnetic field detection circuit 1404 is at a level of about 2.5V. The detection signal output by the Hall detector 1420 is 1000 to 2000 times the original power gain when passing through the first chopper switch 1422, the first chopper amplifier 1424, the sample hold circuit 1426 and the filter circuit 1428. It can be amplified to some magnification between these, preferably 1600 times the original power gain. As a result, the detected actual magnetic voltage signal is amplified so as to be about half the voltage level supplied to the magnetic field detection circuit 1404. In some embodiments, the first chopper amplifier 1424 is configured to achieve a gain that is greater than the gain of the filter circuit 1428. For example, the gain achieved by the first chopper amplifier 1424 can be 50 and the gain achieved by the filter circuit 1428 can be 32.

  FIG. 5 is an exemplary schematic diagram of a rectifier circuit 1402 according to an embodiment of the present teachings. According to the embodiment shown in FIG. 5, a full wave including a first diode 1502, a second diode 1504, a third diode 1506, and a fourth diode 1508 to implement the rectifier circuit 1402. A rectifier bridge is used and the voltage regulator includes a regulation diode 1520. The first diode 1502 and the second diode 1504 are connected in series. A third diode 1506 and a fourth diode 1508 are also connected in series. The cathode of the first diode 1502 and the anode of the second diode 1504 are configured to connect to the input port 1408A that supplies the voltage VAC +. The cathode of the third diode 1506 and the anode of the fourth diode 1508 are configured to connect to the input port 1408B that supplies the voltage VAC−. The anode of the adjustment diode 1502 is connected to the anodes of the first diode 1502 and the third diode 1506 and is further connected to ground. The cathode of the adjustment diode 1520 is connected to the cathodes of the second diode 1504 and the fourth diode 1508 that are both connected to the voltage VDD.

  FIG. 6 is an exemplary circuit diagram of a Hall detector 1420 and a first chopper switch according to an embodiment of the present teachings. According to the illustrated embodiment, in FIG. 6, the Hall detector 1420 and the first chopper switch 1422 are integrated as a single circuit. The Hall detector 1420 includes a Hall detection circuit board having four connection ports 1602, 1604, 1606 and 1608. Connection ports 1602 and 1606 are disposed on opposite sides, and connection ports 1604 and 1608 are disposed on opposite sides. The first chopper switch 1422 includes four switches 1610, 1612, 1614 and 1616. The switch 1610 controls the connection ports 1602 and 1608 to alternately connect to the power supply VCC, and the switch 1612 controls the control connection ports 1604 and 1606 to alternately connect to the ground. The switch 1614 controls the connection ports 1602 and 1608 to alternately output the differential signal P1, and the switch 1616 controls the connection ports 1604 and 1606 to alternately output the differential signal N1. In some embodiments, the Hall detector 1420 and the first chopper switch 1422 allow the other of the connection ports 1602 and 1608 to output the differential signal P1 when one of the connection ports 1602 and 1608 is connected to the power supply VCC. Configured as follows. At the same time, when one of the connection ports 1604 and 1606 is connected to the ground, the other of the connection ports 1604 and 1606 outputs the differential signal N1. For example, when the connection port 1602 is connected to the power supply VCC and the connection port 1606 is connected to the ground, the connection ports 1608 and 1604 output the first differential signal pair {P1, N1}. Separately, when the connection port 1608 is connected to the power supply VCC and the connection port 1604 is connected to the ground, the connection ports 1602 and 1606 output the first differential signal pair {P1, N1}.

  In some embodiments, the power supply VCC can be a constant voltage source implemented by performing a voltage drop and voltage adjustment on the output of the rectifier circuit 1402. In other embodiments, the power supply VCC may be a constant current source.

  In some embodiments, each of switches 1610, 1612, 1614 and 1616 includes a pair of switches configured to be high voltage conduction or low voltage conduction. Each such switch pair can be controlled by a pair of complementary clock signals. Hall detector 1420 and first chopper switch 1422 provide the first differential signal pair {P1, N1} by providing two complementary clock signal pairs of the same frequency to switches 1610, 1612, 1614 and 1616, respectively. Can be generated.

  FIG. 7 shows an exemplary signal output according to the circuit diagram of FIG. The signal CK1 indicates a clock signal. Signal Vos represents the deviation signal inherited in Hall detector 1420. In general, the signal Vos depends on the physical characteristics of the Hall detector 1420. Vin and −Vin indicate actual magnetic field voltage signals output by the first chopper switch 1422 during the first half and the second half of the clock signal CK1, respectively. The actual magnetic field voltage signal is an ideal magnetic field voltage signal associated with the external magnetic field without the interference caused by the deviation signal. The actual magnetic field voltage signal output by the first chopper switch 1422 during the first half and the second half of the clock signal CK1 has the same amplitude and opposite polarity. Vout represents the output of the first chopper switch 1422 which is the actual magnetic field voltage signal Vin or -Vin superimposed or combined with the deviation signal Vos. The first chopper switch 1422 separates the actual magnetic field voltage signal Vin or -Vin and the deviation signal Vos and switches them to the chopper frequency and the baseband frequency, respectively. In some embodiments, the chopper frequency is the frequency of the clock signal CK1, and the baseband frequency is the polarity change frequency of the external magnetic field.

  FIG. 8 is an exemplary circuit diagram of a filter circuit 1428 according to an embodiment of the present teachings. The filter circuit 1428 illustrated in FIG. 4 can include a first filter (F1) 1802 and a second filter (F2) 1804. The first filter (F1) 1802 adds the first stage to each of the two signal pairs {P2A, P2B} and {N2A, N2B} output from the sample hold circuit 1426 in order to remove the deviation signal. Configured to apply. The first filter (F1) 1802 can be further configured to perform first-stage gain amplification on the signal after the first-stage additional processing. The second filter (F2) 1804 applies the second stage addition and / or the second stage gain amplification to the output signal from the first filter (F1) 1802, and applies the third differential signal pair {P3 , N3} can be generated. The gain of the first filter (F1) 1802 can be configured to be smaller than the gain of the second filter (F2) 1804. For example, the gain of the first filter (F1) 1802 is 4, and the gain of the second filter (F2) 1804 is 8.

  It should be understood that the diagram of filter circuit 1428 described above is for illustrative purposes. The present teachings are not intended to be limiting. Filter circuit 1428 may include more or fewer filters than the filter shown in FIG. In some embodiments, the filter circuit 1428 may include only one filter. However, in this situation, this only filter needs to be configured with a large resistance to achieve better gain.

  FIG. 9 is an exemplary circuit diagram of a comparison circuit 1430 according to an embodiment of the present teachings. The comparison circuit 1430 of FIG. 4 can perform the same function as the A / D conversion element 1114 of FIG. In this embodiment, the comparison circuit 1430 can be a delay comparator that includes a first comparator (C1) 1902, a second comparator (C2) 1904, and a latch logic circuit (S) 1906. . The input to the first comparator (C1) 1902 is a third differential signal pair {P3, N3}, a reference voltage pair {Vh, Vl} with a high voltage signal Vh and a low voltage signal Vl. including. The input to the second comparator (C2) 1904 is input to the first comparator (C1) 1902 except that the reference voltage pair {Vh, Vl} is connected with the opposite polarity. Includes the same signal pair. The first comparator (C1) 1902 is configured to calculate the output voltage V1 (V1 = P3-N3) from the filter 1408 and the high voltage threshold Rh (Rh = Vh-Vl). The first comparator (C1) 1902 compares the output voltage V1 with the high voltage threshold Rh. When V1> Rh, the first comparator (C1) 1902 outputs high, and when V1 <Rh, the first comparator (C1) 1902 outputs low. The second comparator (C2) 1904 is configured to compare the output voltage V1 from the filter 1408 with a low voltage threshold Rl (Rl = Vl−Vh). When V1> Rl, the second comparator (C2) 1904 outputs high, and when V1 <Rl, the second comparator (C2) 1904 outputs low. Since Rh is larger than Rl, V1> Rl when V1> Rh, and both the first comparator (C1) 1902 and the second comparator (C2) 1904 output high. When V1 <Rl, V1 <Rh, and the first comparator (C1) 1902 and the second comparator (C2) 1904 both output low. When Rl <V1 <Rh, the first comparator (C1) 1902 outputs a low level, and the second comparator (C2) 1904 outputs a high level. The comparison results from the first comparator (C1) 1902 and the second comparator (C2) 1904 are sent to the latch logic circuit (S) 1906. The latch logic circuit (S) 1906 is configured to generate a voltage signal based on the comparison result. This voltage signal is further sent to the output control circuit 1406 to control the operating state of the magnetic sensor. Details of how the latch logic circuit (S) 1906 generates a voltage signal based on the comparison result will be described below.

  FIG. 10 is an exemplary schematic for determining the polarity of a magnetic field according to an embodiment of the present teachings. The latch logic circuit (S) 1906 receives the comparison results from the first comparator (C1) 1902 and the second comparator (C2) 1904, and the output voltage V1 of the filter circuit 1428 is greater than the output voltage Rh. When indicated by the comparison result, a first signal indicating a change to the sink current state is generated. The latch logic circuit (S) 1906 receives the comparison results from the first comparator (C1) 1902 and the second comparator (C2) 1904, and the comparison result indicates that the output voltage of the filter circuit 1428 is less than Rl. If indicated, a second signal indicating a change to the source current state is generated. The latch logic circuit (S) 1906 receives from the first comparator (C1) 1902 and the second comparator (C2) 1904, and the comparison result indicates that the output voltage V1 of the filter circuit 1428 satisfies Rl <V1 <Rh. In the case indicated by, a third signal indicating that there is no change in state is generated. In some embodiments, the first voltage indicates that the external magnetic field represents a first polarity, and the second voltage indicates that the external magnetic field represents a second polarity.

  FIG. 10 shows that in some embodiments, the comparison circuit 1430 generates a first signal when the magnetic field strength of the external magnetic field reaches the action point Bop, and compares when the magnetic field strength of the external magnetic field is less than the release point Brp. Circuit 1430 is shown generating a second signal. When the magnetic field strength of the external magnetic field exists between the action point Bop and the release point Brp, the comparison circuit 1430 continues to output the current as it is.

  FIG. 11 illustrates an exemplary signal output in a clock cycle according to an embodiment of the present teachings. As shown in FIG. 11A, the first differential signal pair {P1, N1} is the output of the first chopper switch 1422, and the second differential signal pair {P2, N2} The output of the chopper amplifier 1424 and the third differential signal pair {P3, N3} are the output of the filter circuit 1428. {P1A, N1A} is a differential signal pair output from the first chopper switch 1422 during the first half of the clock cycle, and {P1B, N1B} is from the first chopper switch 1422 during the second half of the clock cycle. This is a differential signal pair to be output. {P2A, N2A} is a differential signal pair output from the first chopper amplifier 1424 during the first half of the clock cycle, and {P2B, N2B} is from the first chopper amplifier 1424 during the second half of the clock cycle. This is a differential signal pair to be output.

（１） As described above, Vout indicates the output of the first chopper switch 1422 that is the actual magnetic field voltage signal Vin or −Vin superimposed on the deviation signal Vos. In another aspect, Vout indicates the difference between a first differential signal pair {P1, N1} having the same amplitude and opposite polarity. Therefore, P1A, P1B, N1A and N1B are represented by the following equations:

(1)

（２） When the first chopper amplifier 1424 of FIG. 4 implements the embodiment shown in FIG. 3B, the first chopper amplifier 1424 includes a first amplifier (A1) 1302, a second chopper switch (Z2) 1304, and , And a second amplifier (A2) 1306. The first differential signal pair {P1, N1} passes through the first amplifier (A1) 1302 and is then amplified to the differential signal {P1 ′, N1 ′}. {P1 ′, N1 ′} and the respective components of this signal during the first and second half of the clock cycle are represented by the following equations:

(2)

  A represents the amplification gain of the first amplifier (A1) 1302. Voff denotes a deviation signal output by the first amplifier (A1) 1302, including a deviation signal Vos generated by the Hall detector 1420 and a deviation signal generated by the first amplifier (A1) 1302. For purposes of explanation, the coefficients A and 1/2 are ignored from the description herein below.

（３） The second chopper switch (Z2) 1304 directly outputs the amplified differential signal {P1, N1} during the first half of the clock cycle, and switches the amplified differential signal {P1, N1} during the second half of the clock cycle. The output from the second chopper switch (Z2) 1304 includes two components in each half of the clock cycle. After passing through the sample hold circuit 1426, four components {P2A, P2B, N2A, N2B} represented by the following equations are input to the filter circuit 1428.

(3)

（４） Further, the third differential signal pair {P3, N3} output by the filter circuit 1428 is represented by the following equation.

(4)

  As shown in the above equation, the deviation signal in the third differential signal pair {P3, N3} is removed by the filter circuit 1428. Therefore, the third differential signal pair {P3, N3} includes only the actual magnetic field voltage signal.

  In FIG. 11B, after the first chopper switch (for example, 1202 in FIG. 2), the actual magnetic field voltage signal Vin and the deviation signal Voff are 400 kHz, which is the frequency of the clock signal, and the baseband of 100 Hz. It shows that it is separated into each frequency. After the second chopper switch (eg, 1304 in FIGS. 3A and 3B), the actual magnetic field voltage signal Vin and the deviation signal Voff are switched to the baseband frequency and the chopper frequency, respectively. Thereafter, after the filter circuit (eg, 1206 in FIG. 2), the deviation signal Voff is filtered out. If the magnetic sensor is implemented to control a synchronous motor, the external magnetic field can be a permanent motor magnetic field with a polarity change frequency that is twice the AC power frequency. When power is supplied to the synchronous motor using a 50 Hz or 60 Hz city AC power source, the baseband frequency is 100 Hz or 120 Hz. The actual magnetic field voltage signal and deviation signal are separated into an ultra wide frequency range after passing through a plurality of chopper switches and amplifiers. Accordingly, the chopper amplifier implemented in the present teachings is configured to accommodate an ultra wide frequency range.

  FIG. 12 is an exemplary circuit diagram of the output control circuit 1406 according to an embodiment of the present teachings. The output control circuit 1406 according to the illustrated embodiment includes a first switch 2202 and a second switch 2204. The first switch 2202 is coupled to the output port 1410 to form a first current path, and the second switch 2204 is coupled to the output port 1410 to form a second current path. Current flows in the opposite direction through the first and second current paths. The first switch 2202 and the second switch 2204 are controlled to be selectively connected by a magnetic detection signal. In some embodiments, the first switch 2202 is a transistor and the second switch 2204 is either a diode or a transistor.

  In some embodiments, the first switch 2202 is configured as a low voltage pass and the second switch 2204 is formed as a high voltage pass. Control ends of the first switch 2202 and the second switch 2204 are connected to the output of the magnetic detection circuit 1404. The output of the first switch 2202 and the input of the second switch 2204 are both connected to the output port 1410. The input of the first switch 2202 can be connected to a high voltage end 2206 such as an output VDD from a DC power supply or rectifier circuit 1402, for example, and the output of the second switch 2204 can be connected to a low voltage end such as ground. Part 2208 can be connected. When the output of the magnetic detection circuit 1404 is a low voltage signal, the first switch 2202 is connected and the second switch 2204 is disconnected. As a result, the load current flows from the high voltage end 2206 into the first switch 2202 and flows out through the output port 1410. When the output of the magnetic detection circuit 1404 is a high voltage signal, the second switch 2204 is connected and the first switch 2202 is disconnected. As a result, the load current flows from the output port 1410 to the second switch 2204 and flows out through the low voltage end 2208.

  FIG. 13 is an exemplary circuit diagram of an output control circuit according to another embodiment of the present teachings. The output control circuit 1406 according to the illustrated embodiment includes a first switch 2302 and a second switch 2304. The first switch 2302 is configured as a high voltage passing unit, and the second switch 2304 is configured as a unidirectional diode. The control end of the first switch 2302 and the cathode of the second switch 2304 are both connected to the output of the magnetic detection circuit 1404. In some embodiments, the control end of the first switch 2302 is connected to the output of the magnetic detection circuit 1404 via a resistor 2308. The input of the first switch 2302 can be connected to the output of the rectifier circuit 1402 (see FIG. 4). The output of the first switch 2302 and the anode of the second switch are both connected to the output port 1410. Similar to the embodiment shown in FIG. 12, the first switch 2302 is coupled to the output port 1410 to form a first current path, and the second switch 2304 is coupled to the output port 1410 to couple the second current path. A current path is formed. The current flows in the reverse direction through the first current path and the second current path. When the output of the magnetic detection circuit 1404 is a high voltage signal, the first switch 2302 is connected and the second switch 2304 is disconnected. As a result, the load current flows into the first switch 2302 from the high voltage end 2306 and flows out through the output port 1410. When the output of the magnetic detection circuit 1404 is a low voltage signal, the second switch 2304 is connected and the first switch 2302 is disconnected. As a result, a load current flows from the output port 1410 to the second switch 2304.

  FIG. 14 is an exemplary circuit diagram of an output control circuit according to yet another embodiment of the present teachings. The output control circuit 1406 according to the illustrated embodiment includes a one-way switch 2402 and a resistor 2404. The one-way switch 2402 is connected between the magnetic field detection circuit 1404 and the output port 1410 to form a first current path, and the resistor 2404 is connected between the magnetic field detection circuit 1404 and the output port 1410. Two current paths are formed, and the current flows in the reverse direction through the first current path and the second current path. When the output of the magnetic detection circuit 1404 is a high voltage signal, a one-way switch 2402 is connected, and a load current flows from the output terminal of the magnetic field detection circuit 1404 to the output port 1410 through the one-way switch 2402. When the output of the magnetic detection circuit 1404 is a low voltage signal, the one-way switch 2402 is disconnected, and a load current flows from the output port 1410 through the resistor 2404 to the output terminal of the magnetic field detection circuit 1404.

  The magnetic sensor of the present teachings can be directly connected to a city AC power source without the need for additional A / D conversion facilities. Thus, the present teachings facilitate the mounting of magnetic sensors in various fields. Furthermore, the magnetic field detection circuit can effectively amplify the detected magnetic field signal, adjust the voltage, and filter the interference signal. Thus, the magnetic sensor can control the operation of the electric rotor by generating an accurate signal with respect to the polarity of the external magnetic field.

  FIG. 15 is an exemplary schematic diagram of a motor 2500 incorporating a magnetic sensor constructed in accordance with the present teachings. This motor includes an AC power source 2502, a motor 2504, a magnetic sensor 2508, and a bidirectional switch 2510. In some embodiments, the motor 2500 can further include a voltage drop circuit 2506 configured to reduce the level of the AC power source 2502 prior to supply to the magnetic sensor 2508. The output Pout of the magnetic sensor 2508 is electrically connected to the control end of the bidirectional switch 2510.

  In some embodiments, if the AC power source 2502 operates in a positive half cycle and the magnetic field detection circuit 1404 in the magnetic sensor 2508 determines that the external magnetic field indicates the first polarity, the magnetic sensor 2508 may be both The directional switch 2510 is configured to output a drive current. Separately, when the AC power source 2502 operates in a negative half cycle, and the magnetic field detection circuit 1404 in the magnetic sensor 2508 determines that the external magnetic field indicates a second polarity opposite to the first polarity, An output control circuit 1406 in the magnetic sensor 2508 is configured to control the magnetic sensor 2508 to output a drive current to the bidirectional switch 2510. When the AC power source 2502 operates in the negative half cycle and the magnetic field detection circuit 1404 in the magnetic sensor 2508 determines that the external magnetic field indicates the first polarity, or the AC power source 2502 operates in the positive half cycle, When the magnetic field detection circuit 1404 in the magnetic sensor 2508 determines that the external magnetic field has the second polarity, the output control circuit 1406 in the magnetic sensor 2508 does not output a drive current to the bidirectional switch 2510. Further configured to control 2508.

  In an embodiment in which the magnetic sensor 2508 uses the rectifier circuit shown in FIG. 5 and the output control circuit shown in FIG. 12, the input terminal of the first switch 2202 in FIG. 12 is the voltage output VDD of the bridge full-wave rectifier in FIG. And the output of the second switch 2204 is configured to connect to ground. When the AC power supply 2502 operates in a positive half cycle and the magnetic field detection circuit 1404 outputs a low voltage, the first switch 2202 is connected and the second switch is disconnected, and the AC power supply 2502, the motor 2504, and VAC + A current flows in the direction passing through the magnetic sensor 2508 and the bidirectional switch 2510. In the magnetic sensor 2508, a current flows through the voltage output of the bridge full-wave rectifier and the first switch 2202. In some embodiments, current flows in the voltage drop circuit 2506 before the magnetic sensor 2508. When the AC power supply 2502 operates in a negative half cycle and the magnetic field detection circuit 1404 outputs a high voltage, the first switch 2202 is disconnected and the second switch is connected, and the AC output power supply 2502 and the bidirectional switch 2510, current flows in the reverse direction through the magnetic sensor 2508 and the motor 2504. Within the magnetic sensor 2508, current flows through the second switch 2204, the ground output of the bridge full-wave rectifier, the first diode 1502, and VAC +. When AC power supply 2502 operates in a positive half cycle and magnetic field detection circuit 1404 outputs a high voltage, or AC power supply 2502 operates in a negative half cycle and magnetic field detection circuit 1404 outputs a low voltage, Both the first switch 2202 and the second switch 2204 are disconnected. As a result, no drive current flows through Pout of the magnetic sensor 2508.

  FIG. 16 is an exemplary schematic diagram of a synchronous motor 2600 incorporating a magnetic sensor constructed in accordance with the present teachings. Synchronous motor 2600 includes a stator and a rotor 2602 configured to rotate relative to the stator. The stator includes a stator core 2604 and a stator winding 2612 configured to be wound around the stator core. The stator core 2604 can be made of any soft magnetic material such as iron, cast iron, electric furnace steel, and silicon. When the rotor 2602 is connected in series to an AC power source, the frequency of the AC power source is f, and the rotor 2602 rotates at a constant speed of 60 f / p (rpm rpm) where the number of pole pairs of the rotor 2602 is p. Configured as follows.

  Stator core 2604 is configured to include a pair of opposing magnetic pole portions 2608A and 2608B. Each of the pair of opposing magnetic pole portions (2608A, 2608B) includes magnetic pole arc surfaces such as magnetic pole arc surfaces 2610A and 2610B, for example. The surface of the rotor 2602 faces these magnetic pole arc surfaces (2608A, 2608B) and forms a gap 2606 therebetween. In some embodiments, the majority of the air gap 2606 between the rotor 2602 and the stator is uniform and there are only a few non-uniform air gap regions. In some embodiments, each of the pole faces (2610A and 2610B) is further configured to include a starting groove, such as 2614, for example. The magnetic pole arc surfaces (2610A, 2610B) are concentric with the rotor 2602 except for the start groove region. The configuration of the start groove creates an internally non-uniform magnetic field. Furthermore, the configuration of the starting groove ensures that the polar line S1 of the rotor 2602 is inclined with respect to the central polar line S2 of the magnetic pole portions 2608A and 2608B when the rotor 2602 is stationary. In such a configuration, the rotor 2602 can have a starting torque each time the motor is turned on. In this embodiment, the polar line S1 of the rotor 2602 is the separation boundary between the two magnetic poles of the rotor 2602, and the central polar line S2 passes through the centers of the opposing magnetic pole portions 2608A and 2608B. Both the stator and the rotor 2602 are formed to have two magnetic poles.

  The output control circuit 1406 according to the present teaching controls the bidirectional switch 2510 to switch between the connected state and the disconnected state based on the polarity of the AC power source 2502 and the polarity of the external magnetic field, and the operating state of the stator coil 2612. Further control. This ensures that the magnetic field generated by the stator is driven to rotate the rotor in a single direction in coordination with the magnetic field position of the rotor 2602, thus ensuring that the motor has a constant direction of rotation for each actuation.

  It should be understood that the above examples are for illustrative purposes. The present teachings are not intended to be limiting. The stator and rotor 2602 can also be configured to have different magnetic poles, such as four or six magnetic poles. The stator and rotor 2602 can also have different magnetic poles relative to each other.

  Those skilled in the art will recognize that the present teachings can be variously modified and / or enhanced. For example, the implementation of the various components described above can be implemented by a hardware device, but it can also be implemented as a software-only solution such as introduction into an existing server. Also, the host node and client node units disclosed herein may be implemented as firmware, firmware / software combinations, firmware / hardware combinations, or hardware / firmware / software combinations.

  While what has been considered the best mode and / or other examples have been described, various modifications can be made to them, and the subject matter disclosed herein can be implemented in various forms and examples. It should be understood that the present teachings can be applied to numerous applications, only a portion of which is described herein. The following utility model registration claims are intended to request utility model registration for any and all applications, modifications and variations that fall within the true scope of the present teachings.

Claims (10)

A magnetic sensor,
An input port connected to an external power supply;
A magnetic field detection circuit configured to generate a magnet detection signal;
An output control circuit configured to control operation of the magnetic sensor in response to the magnet detection signal;
An output port;
The magnetic field detection circuit comprises:
A magnetic sensing element configured to detect an external magnetic field and output a detection signal;
A signal processing element configured to amplify the detection signal and remove interference from the detection signal to generate a processed detection signal;
A conversion element configured to convert the processed detection signal to the magnet detection signal;
The magnet detection signal is used to control the magnetic sensor to operate in at least one of the first state and the second state in response to at least the magnet detection signal;
In the first state, a load current flows from the output port to the outside of the magnetic sensor,
In the second state, a load current flows from the outside into the output port of the magnetic sensor,
The signal processing element includes a folded cascode amplifier;
Magnetic sensor characterized by the above. The detection signal includes a magnetic field signal and a deviation signal,
The signal processing element includes:
A first chopper switch configured to separate the detection signal into the deviation signal and the magnetic field signal respectively corresponding to a chopper frequency and a baseband frequency;
A chopper amplifier configured to amplify the deviation signal and the magnetic field signal, and switch the amplified deviation signal and the amplified magnetic field signal to the chopper frequency and the baseband frequency, respectively;
A filter circuit configured to filter out the deviation signal of the chopper frequency;
including,
The magnetic sensor according to claim 1. The chopper amplifier is
A first amplifier;
A second chopper switch;
Including
The first amplifier performs first-stage amplification on the deviation signal and the magnetic field signal from the first chopper switch to generate the amplified deviation signal and the amplified magnetic field signal, respectively. A folded cascode amplifier configured as follows:
The second chopper switch is configured to switch the amplified deviation signal and the amplified magnetic field signal to the chopper frequency and the baseband frequency, respectively.
The magnetic sensor according to claim 2. The chopper amplifier further includes a second amplifier connected in series with the second chopper switch,
The second amplifier is configured to perform second-stage amplification on the amplified deviation signal switched to the chopper frequency and the amplified magnetic field signal switched to the baseband frequency. The
The magnetic sensor according to claim 3. The signal processing element further includes a sample and hold circuit coupled between the chopper amplifier and the filter circuit;
The sample and hold circuit is configured to sample the first differential signal pair during the first half and the second half of the clock cycle, respectively, and output two sampled differential signal pairs during the clock cycle.
The magnetic sensor according to claim 2. The filter circuit further amplifies the second differential signal pair and a first filter configured to calculate a second differential signal pair based on the two sampled differential signal pairs And a second filter configured to remove the deviation signal to generate a third differential signal pair,
The magnetic sensor according to claim 5. An integrated circuit for a magnetic sensor,
An input port connected to an external power supply;
An output port;
A magnetic field detection circuit configured to generate a magnet detection signal;
The magnetic field detection circuit comprises:
A magnetic sensing element configured to detect an external magnetic field and output a detection signal including a magnetic field signal and a deviation signal;
A signal processing element configured to amplify the detection signal, remove interference and generate a processed detection signal;
A conversion element configured to convert the processed detection signal to the magnet detection signal;
The magnet detection signal is used to control the magnetic sensor to operate in at least one of the first state and the second state in response to at least the magnet detection signal;
The signal processing element includes:
A first chopper switch configured to separate the detection signal into a magnetic field signal and a deviation signal respectively corresponding to a chopper frequency and a baseband frequency;
A chopper amplifier configured to separately amplify the magnetic field signal and the deviation signal, and to switch the amplified deviation signal and the amplified magnetic field signal to the chopper frequency and the baseband frequency, respectively;
A filter circuit configured to remove the deviation signal switched to the chopper frequency;
The signal processing element includes a folded cascode amplifier;
An integrated circuit for a magnetic sensor. A rectifier circuit coupled to the input port, the rectifier circuit providing a voltage source to the magnetic field detection circuit;
The integrated circuit for magnetic sensors according to claim 7. The external power source is an alternating current (AC) power source,
The magnet detection signal is a switching detection signal,
The switching frequency of the magnetic detection signal is proportional to the frequency of the AC power source or twice the frequency of the AC power source.
The integrated circuit for magnetic sensors according to claim 7. A motor assembly,
A motor driven by AC power;
A magnetic sensor according to any one of claims 1 to 6, or an integrated circuit for a magnetic sensor according to claims 7 to 9,
A motor assembly comprising:

Images