Wheel speed sensor chip and control method thereof

Abstract

The present invention discloses a wheel speed sensor chip and its control method. The wheel speed sensor chip includes an AMR head, a Hall head, and an ASIC chip. The AMR head detects the raw magnetic signal of the target wheel and sends the acquired raw magnetic signal to the ASIC chip. The Hall head identifies the polarity of the target wheel's magnetic field and obtains the magnetic field magnitude, sending the acquired magnetic field signal to the ASIC chip. The ASIC chip receives the raw magnetic signal of the target wheel obtained by the AMR head and the magnetic field signal obtained by the Hall head, and decodes and outputs the signal. When the raw magnetic signal passes through the origin, the ASIC chip utilizes the natural frequency multiplication characteristics obtained by the AMR head to output a signal. When the raw magnetic signal does not pass through the origin, the ASIC chip generates and outputs a frequency multiplication signal. The wheel speed sensor chip and its control method proposed in the present invention can improve immunity to low-frequency magnetic fields. Even under low-frequency magnetic field interference, the signal output by the wheel speed sensor chip will not show sudden changes.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors and relates to a sensor, and in particular to a wheel speed sensor chip and a control method thereof. Background Art

[0002] The wheel speed sensor is a sensor used to monitor the rotation speed of the car's wheels. The wheel speed sensor is indispensable for modern cars, especially new energy vehicles, and plays a vital role in providing information feedback to help cars achieve L3 and above autonomous driving.

[0003] Traditional wheel speed sensors mostly use Hall effect sensors. However, with the increasing demand for more precise vehicle speed control, newer wheel speed sensors are beginning to utilize GMR (Geomagnetic Field Sensor) technology. However, GMR technology has drawbacks: its immunity to low-frequency magnetic field interference is limited. When low-frequency magnetic field interference is present, the wheel speed sensor output signal can experience sudden changes, impacting the proper functioning of the control system.

[0004] In view of this, there is an urgent need to design a new wheel speed sensor to overcome at least some of the above-mentioned defects of the existing wheel speed sensors. Summary of the Invention

[0005] The present invention provides a wheel speed sensor chip and a control method thereof, which can improve the immunity to low-frequency magnetic fields. Under the condition of low-frequency magnetic field interference, the signal output by the wheel speed sensor chip will not show sudden changes.

[0006] In order to solve the above technical problems, according to one aspect of the present invention, the following technical solution is adopted:

[0007] A wheel speed sensor chip, comprising:

[0008] The AMR head is used to detect the original magnetic signal of the target wheel and send the obtained original magnetic signal to the ASIC chip;

[0009] The Hall effect head is used to identify the polarity of the target wheel's magnetic field and obtain the magnitude of the magnetic field, and send the obtained magnetic field signal to the ASIC chip;

[0010] The ASIC chip is used to receive the original magnetic signal of the target wheel obtained by the AMR head and the magnetic field signal obtained by the Hall head, and decode and output them; the ASIC chip determines whether the original magnetic signal passes through the origin of the set coordinate system based on the magnetic field signal sent by the Hall head; when the original magnetic signal passes through the origin, the ASIC chip outputs a signal using the natural frequency doubling characteristic obtained by the AMR head; when the original magnetic signal does not pass through the origin, the ASIC chip generates and outputs a frequency doubling signal.

[0011] As an embodiment of the present invention, when the original magnetic signal does not pass through the origin, the ASIC chip generates a frequency-doubled signal in a manner including: adjusting the original output of one periodic signal per cycle to outputting two periodic signals per cycle.

[0012] As an embodiment of the present invention, the output of the Hall head completely replicates the original signal of the magnetic field and distinguishes between positive and negative, and the Hall head sends the true situation of the magnetic field to the ASIC chip;

[0013] When there is low-frequency magnetic field interference, the Hall head feeds back the field strength containing north and south pole information to the ASIC chip; the ASIC chip controls the frequency of the output signal through internal logic control to prevent the output signal from changing suddenly.

[0014] As an embodiment of the present invention, based on the characteristic of AMR obtaining symmetrical output under north and south pole magnetic fields, the AMR head can obtain two cycles of sine or cosine signals under a north and south pole cycle magnetic field, thereby achieving a natural frequency doubling characteristic.

[0015] As an embodiment of the present invention, the AMR head integrates two full-bridge design heads, and each bridge realizes differential through a fixed spacing and in conjunction with a target wheel;

[0016] The AMR head integrates two full-bridge design heads, and realizes the phase difference of the two signals by the sequence between the two signals and the rotation of the target wheel, so as to distinguish the forward and reverse rotation of the target wheel.

[0017] As an embodiment of the present invention, the wheel speed sensor chip further includes a capacitor, the ASIC chip is connected to the capacitor, and the capacitor is used to improve the electromagnetic compatibility (EMC) performance of the wheel speed sensor chip.

[0018] The Hall magnetic head is integrated inside the ASIC chip. The ASIC chip, the AMR magnetic head and the capacitor are packaged in a SIP package and integrated into the same package.

[0019] As an embodiment of the present invention, the Hall head is integrated into the ASIC chip, or the Hall head exists independently of the ASIC chip; the Hall head is a vertical Hall head, which is used to sense horizontal magnetic fields.

[0020] According to another aspect of the present invention, the following technical solution is adopted: a control method for a wheel speed sensor chip, the control method comprising:

[0021] The AMR head detects the original magnetic signal of the target wheel and sends the acquired original magnetic signal to the ASIC chip;

[0022] The Hall effect head identifies the polarity of the target wheel's magnetic field and obtains the magnitude of the magnetic field, and sends the obtained magnetic field signal to the ASIC chip;

[0023] The ASIC chip receives the original magnetic signal of the target wheel obtained by the AMR head and the magnetic field signal obtained by the Hall head, and decodes and outputs them; the ASIC chip determines whether the original magnetic signal passes through the origin of the set coordinate system based on the magnetic field signal sent by the Hall head; when the original magnetic signal passes through the origin, the ASIC chip outputs a signal using the natural frequency doubling characteristics obtained by the AMR head; when the original magnetic signal does not pass through the origin, the ASIC chip generates and outputs a frequency doubling signal.

[0024] As an embodiment of the present invention, when the original magnetic signal does not pass through the origin, the ASIC chip generates a frequency-doubled signal in a manner including: adjusting the original output of one periodic signal per cycle to outputting two periodic signals per cycle.

[0025] As an embodiment of the present invention, the output of the Hall head completely replicates the original signal of the magnetic field and distinguishes between positive and negative, and the Hall head sends the true situation of the magnetic field to the ASIC chip;

[0026] When there is low-frequency magnetic field interference, the Hall head feeds back the field strength containing north and south pole information to the ASIC chip; the ASIC chip controls the frequency of the output signal through internal logic control to prevent the output signal from changing suddenly.

[0027] The beneficial effects of the present invention are that the wheel speed sensor chip and its control method can improve immunity to low-frequency magnetic fields. Even under low-frequency magnetic field interference, the wheel speed sensor chip's output signal will not experience sudden changes. Furthermore, the present invention can improve detection resolution, thereby enhancing control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 FIG. 1 is a schematic diagram of the composition of a wheel speed sensor chip in one embodiment of the present invention.

[0029] Figure 2 FIG. 4 is a flow chart of a method for controlling a wheel speed sensor chip according to an embodiment of the present invention.

[0030] Figure 3 This is a schematic diagram showing the output of the ASIC chip using only the AMR head sensing signal.

[0031] Figure 4 This is a schematic diagram showing the output of the ASIC chip sensing signals through the AMR head and Hall head.

[0032] Figure 5Schematic diagram of outputting the corresponding AMR output signal using the PWM protocol.

[0033] Figure 6 Schematic diagram of outputting the corresponding AMR output signal using the AK protocol.

[0034] Figure 7 Schematic diagram of outputting the corresponding AMR output signal using the standard protocol. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0036] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0037] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments described. The same or similar existing technical means and some technical features of the embodiments are mutually replaced within the scope of the description and protection of the present invention.

[0038] The description of the steps in each embodiment in the specification is only for the convenience of explanation, and the implementation method of this application is not limited by the order of implementation of the steps.

[0039] The term "connection" as used in this specification includes both direct connection and indirect connection, such as connection through active devices, passive devices or electrically conductive media; it may also include connection through other active devices or passive devices that are well known to those skilled in the art and can achieve the same or similar functional purposes, such as connection through circuits or components such as switches and follower circuits.

[0040] The present invention discloses a wheel speed sensor chip. Figure 1 This is a schematic diagram of the composition of a wheel speed sensor chip in one embodiment of the present invention; please refer to Figure 1 The wheel speed sensor chip includes: an AMR head 2, a Hall head 3 and an ASIC chip 1.

[0041] The AMR head 2 is used to detect the original magnetic signal of the target wheel and send the obtained original magnetic signal to the ASIC chip 1; the Hall head 3 is used to identify the polarity of the target wheel magnetic field and obtain the magnetic field size, and send the obtained magnetic field signal to the ASIC chip 1.

[0042] The ASIC chip 1 is configured to receive the original magnetic signal of the target wheel acquired by the AMR head 2 and the magnetic field signal acquired by the Hall head 3, and decode and output the signal. Based on the magnetic field signal transmitted by the Hall head 3, the ASIC chip 1 determines whether the original magnetic signal passes through the origin of a predetermined coordinate system. When the original magnetic signal passes through the origin, the ASIC chip 1 utilizes the natural frequency doubling characteristic acquired by the AMR head to output a signal. When the original magnetic signal does not pass through the origin, the ASIC chip 1 generates and outputs a frequency doubling signal. In one embodiment, when the original magnetic signal does not pass through the origin, the ASIC chip 1 generates the frequency doubling signal by adjusting the original output of one periodic signal per cycle to outputting two periodic signals per cycle.

[0043] The ASIC chip 1 can integrate DSP, temperature sensor, EEPROM, oscillator, power stabilization module, etc.; the output mode of the ASIC chip 1 includes at least one of the standard protocol, PWM protocol, and AK protocol (see the signal diagrams of different protocols for output). Figures 5 to 7 shown).

[0044] In one embodiment of the present invention, the output of the Hall head 3 completely replicates the original signal of the magnetic field and distinguishes between positive and negative. The Hall head 3 transmits the true state of the magnetic field to the ASIC chip 1. When there is low-frequency magnetic field interference, the Hall head 3 feeds back the field strength including north and south pole information to the ASIC chip 1. The ASIC chip 1 controls the frequency of the output signal through internal logic control to prevent sudden changes in the output signal. Figure 3 This is a schematic diagram showing the output of the ASIC chip using only the AMR head sensing signal. Figure 4 This is a schematic diagram showing the output of the ASIC chip through the AMR head and Hall head sensing signal; Figure 3 and Figure 4 By comparing the signals sensed by the AMR head and the Hall head, it can be found that the time when low-frequency magnetic field interference occurs can be effectively identified by combining the signals sensed by the AMR head and the Hall head, and the frequency can be switched through the ASIC.

[0045] Based on the characteristic of AMR producing symmetrical outputs in north-south magnetic fields, the AMR head 2 can generate two cycles of sine or cosine signals in a magnetic field with a north-south magnetic field cycle, thereby achieving a natural frequency doubling characteristic. In one embodiment, the AMR head 2 integrates a two-way full-bridge design. By sequentially switching the two channels and coordinating them with the rotation of the target wheel, a phase difference is achieved between the two channels, thereby distinguishing between forward and reverse rotation of the target wheel.

[0046] The AMR head 2 needs to operate in a magnetic field that crosses zero, meaning it flips its north and south poles. In typical wheel speed sensor applications, the sensor faces a multi-pole magnetic wheel, and rotation inevitably causes north and south pole flipping. When the signal crosses zero, the ASIC chip directly outputs the naturally frequency-doubled signal sensed by the AMR head. When the signal does not cross zero, the ASIC chip uses its own algorithm to generate and output a frequency-doubled signal (i.e., it adjusts the original single-cycle output to a double-cycle output per cycle), thus ensuring that the output signal does not experience sudden changes.

[0047] The Hall head 3 can be integrated into the ASIC chip 1 (can be a part of the ASIC chip 1), or the Hall head 3 exists independently of the ASIC chip 1; the Hall head 3 can be a vertical Hall head for sensing horizontal magnetic fields.

[0048] The wheel speed sensor chip may also include a capacitor 4, to which the ASIC chip 1 is connected. This capacitor 4 is used to improve the electromagnetic compatibility (EMC) performance of the wheel speed sensor chip. In one embodiment, the Hall effect head 3 is integrated within the ASIC chip 1. The ASIC chip 1, the AMR head 2, and the capacitor 4 may be packaged in a single SIP package.

[0049] In one embodiment, the wheel speed sensor chip of the present invention is used to work facing a magnetic wheel with multiple pairs of poles to detect changes in the magnetic field of the magnetic wheel during its rotation.

[0050] The present invention further discloses a control method for a wheel speed sensor chip. Figure 2 This is a flow chart of a method for controlling a wheel speed sensor chip according to an embodiment of the present invention; Figure 2 , the control method includes:

[0051] [Step S1] The AMR head detects the original magnetic signal of the target wheel and sends the obtained original magnetic signal to the ASIC chip;

[0052] [Step S2] The Hall effect head identifies the polarity of the target wheel's magnetic field and obtains the magnitude of the magnetic field, and sends the obtained magnetic field signal to the ASIC chip;

[0053] [Step S3] The ASIC chip receives the original magnetic signal of the target wheel acquired by the AMR head and the magnetic field signal acquired by the Hall head, and decodes and outputs them. The ASIC chip determines whether the original magnetic signal passes through the origin of the set coordinate system based on the magnetic field signal sent by the Hall head. When the original magnetic signal passes through the origin, the ASIC chip 1 outputs a signal using the natural frequency doubling characteristic acquired by the AMR head. When the original magnetic signal does not pass through the origin, the ASIC chip 1 generates and outputs a frequency doubling signal. In one embodiment, when the original magnetic signal does not pass through the origin, the ASIC chip 1 generates the frequency doubling signal by adjusting the original output of one periodic signal per cycle to outputting two periodic signals per cycle.

[0054] In the above steps, the order of some steps can be adjusted (such as step S1, step S2), or some steps can be performed simultaneously (such as step S1, step S2).

[0055] The output of the Hall effect head 3 completely replicates the original signal of the magnetic field and distinguishes between positive and negative. The Hall effect head transmits the true state of the magnetic field to the ASIC chip. When there is low-frequency magnetic field interference, the Hall effect head feeds back the field strength including north and south pole information to the ASIC chip. The ASIC chip controls the frequency of the output signal through internal logic control to prevent sudden changes in the output signal.

[0056] In summary, the wheel speed sensor chip and control method proposed in this invention can improve immunity to low-frequency magnetic fields. Even in the presence of low-frequency magnetic interference, the wheel speed sensor output signal will not experience sudden changes. Furthermore, this invention can enhance detection resolution, thereby improving control accuracy.

[0057] It should be noted that the present application can be implemented in software and / or a combination of software and hardware; for example, it can be implemented using an application-specific integrated circuit (ASIC), a general-purpose computer, or any other similar hardware device. In some embodiments, the software program of the present application can be executed by a processor to implement the above steps or functions. Similarly, the software program of the present application (including related data structures) can be stored in a computer-readable recording medium; for example, a RAM memory, a magnetic or optical drive, or a floppy disk and the like. In addition, some steps or functions of the present application can be implemented in hardware; for example, as a circuit that cooperates with a processor to perform various steps or functions.

[0058] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The description and application of the present invention here are illustrative and are not intended to limit the scope of the present invention to the above-described embodiments. The effects or advantages involved in the embodiments may not be embodied in the embodiments due to interference from various factors, and the description of the effects or advantages is not used to limit the embodiments. Variations and changes to the embodiments disclosed here are possible, and the replacement of the embodiments and various equivalent components are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts without departing from the spirit or essential characteristics of the present invention. Other variations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A wheel speed sensor chip, characterized in that: The wheel speed sensor chip includes: The AMR head is used to detect the original magnetic signal of the target wheel and send the obtained original magnetic signal to the ASIC chip; The Hall effect head is used to identify the polarity of the target wheel magnetic field and obtain the magnetic field size, and send the obtained magnetic field signal to the ASIC chips; The ASIC chip is used to receive the original magnetic signal of the target wheel obtained by the AMR head and the magnetic field signal obtained by the Hall head, and decode and output them; the ASIC chip determines whether the original magnetic signal passes through the origin of the set coordinate system based on the magnetic field signal sent by the Hall head; when the original magnetic signal passes through the origin, the ASIC chip outputs a signal using the natural frequency doubling characteristic obtained by the AMR head; when the original magnetic signal does not pass through the origin, the ASIC chip generates and outputs a frequency doubling signal.

2. The wheel speed sensor chip according to claim 1, characterized in that: When the original magnetic signal does not pass through the origin, the ASIC chip generates a frequency-doubled signal in a manner that includes: adjusting the original output of one periodic signal per cycle to outputting two periodic signals per cycle.

3. The wheel speed sensor chip according to claim 1, characterized in that: The output of the Hall head completely replicates the original signal of the magnetic field and distinguishes between positive and negative. The Hall head sends the true situation of the magnetic field to the ASIC chip; When there is low-frequency magnetic field interference, the Hall head feeds back the field strength containing north and south pole information to the ASIC chip; the ASIC chip controls the frequency of the output signal through internal logic control to prevent the output signal from changing suddenly.

4. The wheel speed sensor chip according to claim 1, characterized in that: Based on the characteristic of AMR to obtain symmetrical output under north and south pole magnetic fields, the AMR head can obtain two cycles of sine or cosine signals under a north and south pole cycle magnetic field, thereby achieving a natural frequency doubling characteristic.

5. The wheel speed sensor chip according to claim 1, characterized in that: The AMR head integrates two full-bridge heads, each bridge achieving differential through a fixed spacing and in conjunction with a target wheel; The AMR head integrates two full-bridge design heads, and realizes the phase difference of the two signals by the sequence between the two signals and the rotation of the target wheel, so as to distinguish the forward and reverse rotation of the target wheel.

6. The wheel speed sensor chip according to claim 1, characterized in that: The wheel speed sensor chip further includes a capacitor, the ASIC chip is connected to the capacitor, and the capacitor is used to improve the electromagnetic compatibility (EMC) performance of the wheel speed sensor chip; The Hall magnetic head is integrated inside the ASIC chip. The ASIC chip, the AMR magnetic head and the capacitor are packaged in a SIP package and integrated into the same package.

7. The wheel speed sensor chip according to claim 1, characterized in that: The Hall head is integrated into the ASIC chip, or the Hall head exists independently of the ASIC chip; the Hall head is a vertical Hall head, which is used to sense horizontal magnetic fields.

8. A method for controlling a wheel speed sensor chip, characterized in that: The control method includes: The AMR head detects the original magnetic signal of the target wheel and sends the acquired original magnetic signal to the ASIC chip; The Hall effect head identifies the polarity of the target wheel's magnetic field and obtains the magnitude of the magnetic field, and sends the obtained magnetic field signal to the ASIC chip; The ASIC chip receives the original magnetic signal of the target wheel obtained by the AMR head and the magnetic field signal obtained by the Hall head, and decodes and outputs them; the ASIC chip determines whether the original magnetic signal passes through the origin of the set coordinate system based on the magnetic field signal sent by the Hall head; when the original magnetic signal passes through the origin, the ASIC chip outputs a signal using the natural frequency doubling characteristics obtained by the AMR head; when the original magnetic signal does not pass through the origin, the ASIC chip generates and outputs a frequency doubling signal.

9. The control method according to claim 8, characterized in that: When the original magnetic signal does not pass through the origin, the ASIC chip generates a frequency-doubled signal in a manner that includes: adjusting the original output of one periodic signal per cycle to outputting two periodic signals per cycle.

10. The control method according to claim 8, characterized in that: The output of the Hall head completely replicates the original signal of the magnetic field and distinguishes between positive and negative. The Hall head sends the true situation of the magnetic field to the ASIC chip; When there is low-frequency magnetic field interference, the Hall head feeds back the field strength containing north and south pole information to the ASIC chip; the ASIC chip controls the frequency of the output signal through internal logic control to prevent the output signal from changing suddenly.

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