A signal processing circuit and its handheld terminal

Abstract

This utility model discloses a signal processing circuit and its handheld terminal. The signal processing circuit includes a low-frequency receiving module and a processing module. The output terminal of the low-frequency receiving module is electrically connected to the processing module. The processing module includes a wake-up circuit and a first control chip. The first control chip is configured to receive a wake-up signal sent by the wake-up circuit, causing the first control chip to switch from a sleep state to an operating state. Through this method, when the car smart key is in standby mode, the first control chip remains in a sleep state, and only the low-frequency receiving module and the wake-up circuit are operating. Since the power consumption of the low-frequency receiving module and the wake-up circuit is lower than that of the first control chip, the standby power consumption of the car smart key is reduced, extending the battery life of the car smart key.

Description

Technical Field

[0001] This utility model relates to the field of automotive smart key technology, and in particular to a signal processing circuit and its handheld terminal. Background Technology

[0002] As people's living standards continue to improve, their demands for the user experience of transportation tools are also increasing, especially in terms of ease of use. With the development of automotive electronics technology, more and more cars are adopting Passive Keyless Entry (PKE). Keyless entry means that when a car owner approaches their vehicle with the smart key, the vehicle's PKE system interacts with the smart key to determine if the user is legitimate, and then automatically unlocks the vehicle. The low-frequency detection module in the smart key is always active, waiting for a low-frequency wake-up signal. When the low-frequency detection module detects the low-frequency wake-up signal, the smart key's chip is activated, enabling PKE interaction between the smart key and the vehicle. Because the low-frequency detection module is constantly active to detect the low-frequency wake-up signal, the standby power consumption of the smart key is relatively high. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a signal processing circuit and its handheld terminal to solve the problem that the low-frequency detection module of the car smart key is always in working state to detect low-frequency wake-up signals, resulting in high standby power consumption of the car smart key.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] In a first aspect, this utility model proposes a signal processing circuit, including: a low-frequency receiving module and a processing module, wherein the output terminal of the low-frequency receiving module is electrically connected to the processing module, and the processing module includes: a wake-up circuit and a first control chip, wherein the first control chip is configured to receive a wake-up signal sent by the wake-up circuit, so that the first control chip switches from a sleep state to a working state.

[0006] In one specific embodiment, the low-frequency receiving module includes: a three-dimensional inductor, a resonant capacitor unit, and a second control chip. The output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the resonant capacitor unit is connected in parallel between the output terminal of the three-dimensional inductor and the second control chip, and the other end of the resonant capacitor unit is grounded.

[0007] In one specific embodiment, the resonant capacitor unit includes: a first resonant capacitor circuit, a second resonant capacitor circuit, and a third resonant capacitor circuit. The Z-axis output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the first resonant capacitor circuit is connected in parallel between the Z-axis output terminal of the three-dimensional inductor and the second control chip, and the other end of the first resonant capacitor circuit is grounded. The X-axis output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the second resonant capacitor circuit is connected in parallel between the X-axis output terminal of the three-dimensional inductor and the second control chip, and the other end of the second resonant capacitor circuit is grounded. The Y-axis output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the third resonant capacitor circuit is connected in parallel between the Y-axis output terminal of the three-dimensional inductor and the second control chip, and the other end of the third resonant capacitor circuit is grounded.

[0008] In one specific embodiment, the first resonant capacitor circuit, the second resonant capacitor circuit, and the third resonant capacitor circuit have the same structure. The first resonant capacitor circuit includes a first capacitor, a second capacitor, and a third capacitor. One end of the first capacitor, the second capacitor, and the third capacitor are all connected in parallel between the Z-axis output terminal of the three-dimensional inductor and the second control chip. The other end of the first capacitor, the second capacitor, and the third capacitor are connected in parallel and then grounded.

[0009] In one specific embodiment, the low-frequency receiving module further includes a fourth capacitor, one end of which is electrically connected to the second control chip, and the other end of which is grounded.

[0010] In one specific embodiment, the wake-up circuit includes: a third control chip, the input terminal of which is connected to the output terminal of the second control chip, and the output terminal of which is connected to the first control chip.

[0011] In one specific embodiment, the wake-up circuit further includes a fifth capacitor, one end of which is electrically connected to the third control chip, and the other end of which is grounded.

[0012] In one specific embodiment, the low-frequency receiving module further includes: a second resistor, one end of which is electrically connected to the second control chip, and the other end of which is electrically connected to the third control chip.

[0013] In one specific embodiment, the low-frequency receiving module further includes: a third resistor, one end of which is electrically connected to the second control chip, and the other end of which is electrically connected to the third control chip.

[0014] Secondly, this utility model proposes a handheld terminal, including: the signal processing circuit described above.

[0015] The beneficial effects of this utility model are:

[0016] Compared with existing technologies, the signal processing circuit proposed in this invention ensures that when the car smart key is in standby mode, the first control chip remains in a dormant state, with only the low-frequency receiving module and the wake-up circuit operating. Since the power consumption of the low-frequency receiving module and the wake-up circuit is lower than that of the first control chip, the standby power consumption of the car smart key is reduced, extending the battery life. Furthermore, the combined processing of the low-frequency signal by the low-frequency receiving module and the judgment of the low-frequency received signal by the wake-up circuit ensures that only a valid wake-up signal can wake up the first control chip, preventing false wake-ups and improving the reliability and stability of the car smart key system.

[0017] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this utility model more obvious and easy to understand, the following are preferred embodiments, which are described in detail below. Attached Figure Description

[0018] Figure 1 is a structural block diagram of a signal processing circuit proposed in an embodiment of the present invention;

[0019] Figure 2 This is a circuit schematic diagram of a signal processing circuit proposed in an embodiment of the present invention;

[0020] Figure 3 This is a schematic block diagram of a handheld terminal proposed in an embodiment of the present utility model.

[0021] Explanation of reference numerals in the attached figures:

[0022] 10. Low-frequency receiving module; 20. Processing module. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification. Example

[0030] Firstly, please refer to Figures 1 to 2 This utility model proposes a signal processing circuit, including: a low-frequency receiving module 10 and a processing module 20. The output terminal of the low-frequency receiving module 10 is electrically connected to the processing module 20. The processing module 20 includes: a wake-up circuit and a first control chip U1. The first control chip U1 is configured to receive a wake-up signal sent by the wake-up circuit, so that the first control chip U1 switches from a sleep state to a working state.

[0031] Specifically, the low-frequency receiving module 10 receives a low-frequency wake-up signal from the vehicle and performs preliminary processing on the received weak low-frequency signal (such as signal amplification and filtering) to improve the signal's recognizability. The wake-up circuit in the processing module 20 is electrically connected to the output of the low-frequency receiving module 10 and performs preliminary processing and judgment on the received low-frequency signal. When the received low-frequency signal meets the preset wake-up conditions (such as the signal strength reaching a certain threshold or the signal frequency meeting specific requirements), the wake-up circuit generates a wake-up signal and sends it to the first control chip U1. After receiving the wake-up signal sent by the wake-up circuit, the first control chip U1 in the processing module 20 switches from a sleep state to a working state, processes the received low-frequency signal, and generates a high-frequency signal for communication with the vehicle.

[0032] In practical applications, when the car smart key is in standby mode, the low-frequency receiving module 10 monitors low-frequency signals from the outside, and the first control chip U1 in the processing module 20 is in sleep mode to reduce power consumption. When the low-frequency receiving module 10 receives a low-frequency signal, it performs preliminary processing on the signal (such as signal amplification and filtering), and then transmits the processed low-frequency signal to the wake-up circuit and the first control chip U1 in the processing module 20. The wake-up circuit analyzes and judges the input low-frequency signal. If the low-frequency signal meets the preset wake-up conditions (such as specific frequency, intensity, etc.), the wake-up circuit generates a wake-up signal and sends it to the first control chip U1. After receiving the wake-up signal, the first control chip U1 switches from sleep mode to working mode. At the same time, the second control chip U2 sends a low-frequency signal to the first control chip U1. The first control chip U1 processes the received low-frequency signal to generate a high-frequency signal for communication with the car. If there is no new wake-up signal within a period of time, the first control chip U1 can automatically switch back to sleep mode to reduce energy consumption.

[0033] The signal processing circuit proposed in this embodiment ensures that when the car smart key is in standby mode, the first control chip U1 remains in a dormant state, with only the low-frequency receiving module 10 and the wake-up circuit operating. The power consumption of the low-frequency receiving module 10 and the wake-up circuit is lower than that of the first control chip U1, thus reducing the standby power consumption of the car smart key and extending its battery life. Simultaneously, the cooperation between the low-frequency receiving module 10's processing of low-frequency signals and the wake-up circuit's judgment of low-frequency received signals ensures that only a valid wake-up signal can wake up the first control chip U1, preventing false wake-ups and improving the reliability and stability of the car smart key system.

[0034] Please see Figure 2 The low-frequency receiving module 10 includes: a three-dimensional inductor L1, a resonant capacitor unit, and a second control chip U2. The output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the resonant capacitor unit is connected in parallel between the output terminal of the three-dimensional inductor and the second control chip, and the other end of the resonant capacitor unit is grounded.

[0035] Specifically, the three-dimensional inductor L1 is used to receive low-frequency signals in space, converting weak low-frequency magnetic field signals into electrical signals and outputting them to the second control chip U2. The resonant capacitor unit and the three-dimensional inductor L1 form an LC resonant circuit, which performs frequency selection and amplification on the input low-frequency signal. When the frequency of the input signal is consistent with the resonant frequency of the resonant capacitor unit, the signal is enhanced, and signals at non-resonant frequencies are suppressed, thereby improving the signal-to-noise ratio. The DAT and WAKE terminals of the second control chip U2 are electrically connected to the wake-up circuit to transmit the signal to the wake-up circuit. After receiving the low-frequency signal, the wake-up circuit processes it. If the low-frequency signal meets the preset wake-up conditions (such as a specific frequency, intensity, etc.), the wake-up circuit generates a wake-up signal and sends it to the first control chip U1. After receiving the wake-up signal, the first control chip U1 switches from the sleep state to the working state. The CS, SCL, SDI, and SDO terminals of the second control chip U2 are all electrically connected to the first control chip U1 to send the processed low-frequency signal to the first control chip U1 to generate a high-frequency signal for communication with the vehicle. By placing the first control chip U1 in a sleep state and waking it up only when needed, and using the low-power low-frequency receiving module 10 and the wake-up circuit for signal monitoring and processing, the standby power consumption of the entire circuit is reduced. The frequency selection and amplification of the signal by the resonant capacitor unit, and the judgment of signal characteristics by the second control chip U2, can effectively filter out interference signals, so that the device only responds to specific low-frequency wake-up signals, thereby improving the anti-interference capability of the car smart key in complex electromagnetic environments.

[0036] Please refer to it again. Figure 2 The resonant capacitor unit includes: a first resonant capacitor circuit, a second resonant capacitor circuit, and a third resonant capacitor circuit. The Z-axis output terminal of the three-dimensional inductor L1 is electrically connected to the second control chip U2. One end of the first resonant capacitor circuit is connected in parallel between the Z-axis output terminal of the three-dimensional inductor L1 and the second control chip U2, and the other end of the first resonant capacitor circuit is grounded. The X-axis output terminal of the three-dimensional inductor L1 is electrically connected to the second control chip U2. One end of the second resonant capacitor circuit is connected in parallel between the X-axis output terminal of the three-dimensional inductor L1 and the second control chip U2, and the other end of the second resonant capacitor circuit is grounded. The Y-axis output terminal of the three-dimensional inductor L1 is electrically connected to the second control chip U2. One end of the third resonant capacitor circuit is connected in parallel between the Y-axis output terminal of the three-dimensional inductor L1 and the second control chip U2, and the other end of the third resonant capacitor circuit is grounded.

[0037] Specifically, when a car smart key receives low-frequency signals, it may encounter interference from signals coming from different directions, or it may need to accurately receive signals from different directions. The three-dimensional inductor L1 can receive low-frequency magnetic field signals in three mutually perpendicular directions (X, Y, and Z axes) and convert them into electrical signals, outputting them from the corresponding axis output terminals. This allows for the acquisition of low-frequency signals from different directions in space, providing a foundation for multi-directional signal processing. Three resonant capacitor circuits are set up, each connected to the X, Y, and Z axis output terminals of the three-dimensional inductor L1, forming an independent resonant circuit. When a low-frequency signal passes through the three-dimensional inductor L1, it is distributed to the corresponding resonant capacitor circuit. The resonant frequency of the resonant circuit is determined by the inductance value of the three-dimensional inductor L1 and the total capacitance value of the resonant capacitor units. When the signal frequency is the same as the resonant frequency, the signal will pass smoothly through the resonant circuit, while signals of other frequencies will be attenuated or filtered out, improving the accuracy of signal reception. The Z-axis output terminal of the three-dimensional inductor L1 is electrically connected to the LF1P terminal of the second control chip U2. One end of the first resonant capacitor circuit is connected in parallel between the Z-axis output terminal of the three-dimensional inductor L1 and the second control chip U2. The X-axis output terminal of the three-dimensional inductor L1 is electrically connected to the LF2P terminal of the second control chip U2. One end of the second resonant capacitor circuit is connected in parallel between the X-axis output terminal of the three-dimensional inductor L1 and the second control chip U2. The Y-axis output terminal of the three-dimensional inductor L1 is electrically connected to the LF3P terminal of the second control chip U2. One end of the third resonant capacitor circuit is connected in parallel to the three-dimensional inductor L1. Between the Y-axis output terminal of inductor L1 and the second control chip U2, the other ends of the first, second, and third resonant capacitor circuits are all grounded. When low-frequency signals are received from different directions, the X, Y, and Z-axis coils of the three-dimensional inductor L1 respectively sense the signals, convert them into electrical signals, and transmit these electrical signals to the corresponding resonant capacitor circuits. Each resonant capacitor circuit selects and filters the signals according to a preset resonant frequency. Only signals matching the resonant frequency can pass through the resonant circuit and be transmitted to the second control chip U2. Through the above method, the coordinated work of the three-dimensional inductor L1, the multi-channel resonant capacitor circuits, and the second control chip U2 enables the processing module 20 to process only signals of specific frequencies during signal reception, reducing the power consumption of the car smart key.

[0038] Please refer to it again. Figure 2 The first resonant capacitor circuit, the second resonant capacitor circuit, and the third resonant capacitor circuit have the same structure. The first resonant capacitor circuit includes: a first capacitor C1, a second capacitor C2, and a third capacitor C3. One end of the first capacitor C1, the second capacitor C2, and the third capacitor C3 are all connected in parallel to the Z-axis output terminal of the three-dimensional inductor L1. The other end of the first capacitor C1, the second capacitor C2, and the third capacitor C3 are connected in parallel and then grounded.

[0039] Specifically, one end of the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 of the second resonant capacitor circuit are all connected in parallel between the X-axis output terminal of the three-dimensional inductor L1 and the wake-up unit, and the other end of the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are connected in parallel and then grounded. One end of the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor C9 of the third resonant capacitor circuit are all connected in parallel between the Y-axis output terminal of the three-dimensional inductor L1 and the wake-up unit, and the other end of the seventh capacitor C7, the eighth capacitor C8, and the ninth capacitor C9 are connected in parallel and then grounded.

[0040] It is understandable that one end of each of the first capacitor C1, the second capacitor C2, and the third capacitor C3 is connected in parallel between the Z-axis output of the three-dimensional inductor L1 and the wake-up unit, while the other end is grounded in parallel, forming multiple resonant paths. When a low-frequency signal is input, signals of different frequencies will resonate on different capacitor paths, thereby achieving the selection and filtering of signals of specific frequencies. Furthermore, the first resonant capacitor circuit, composed of multiple capacitors connected in parallel, provides multiple resonant paths for signals of different frequencies, enabling more precise selection, removal of noise and interference signals, and improvement of signal reception accuracy.

[0041] Please refer to it again. Figure 2 In this embodiment, the low-frequency receiving module 10 further includes: a first resistor R1, a second resistor R2, and a third resistor R3. One end of the first resistor R1 is electrically connected to the Z-axis output terminal of the three-dimensional inductor L1, and the other end of the first resistor R1 is connected to the LF1P port of the second control chip U2. One end of the second resistor R2 is electrically connected to the X-axis output terminal of the three-dimensional inductor L1, and the other end of the second resistor R2 is connected to the LF2P port of the second control chip U2. One end of the third resistor R3 is electrically connected to the Y-axis output terminal of the three-dimensional inductor L1, and the other end of the third resistor R3 is connected to the LF3P port of the second control chip U2. According to Ohm's law, the resistor will produce a voltage divider effect on the signal in the circuit. When the car smart key is working, the Z-axis, X-axis, and Y-axis of the three-dimensional inductor L1 output corresponding signals respectively. After these signals are processed by voltage divider resistors R1, R2, and R3, the amplitude and impedance of the signals are adjusted to the range that the second control chip U2 in the wake-up unit can receive, preventing circuit failures caused by excessively strong signals or interference, and improving the stability of the car smart key operation.

[0042] Please refer to it again. Figure 2 The low-frequency receiving module 10 also includes a fourth capacitor C4, one end of which is electrically connected to the second control chip U2, and the other end of which is grounded.

[0043] Specifically, one end of the fourth capacitor C4 is electrically connected to the VCC terminal of the second control chip U2, and the other end is grounded, so that the power supply pin of the second control chip receives a stable voltage, reducing the impact of power supply noise and voltage fluctuations on the performance of the second control chip U2.

[0044] Please refer to it again. Figure 2 The wake-up circuit includes: a third control chip U3, the input terminal of the third control chip U3 is connected to the output terminal of the second control chip U2, and the output terminal of the third control chip U3 is connected to the first control chip U1.

[0045] Specifically, the DAT terminal of the second control chip U2 is electrically connected to the fifth CPIO terminal of the third control chip U3, and sends the processed low-frequency signal data to the fifth CPIO terminal of the third control chip U3. The WAKE terminal of the second control chip U2 is electrically connected to the fourth CPIO terminal, and the WAKE terminal of the second control chip U2 is used to receive the wake-up signal from the fourth CPIO terminal of the third control chip U3. When the third control chip U3 determines that the data meets the wake-up conditions, it sends a wake-up signal to the WAKE terminal of the second control chip U2 through the fourth CPIO terminal. Through the signal processing and judgment logic of the third control chip U3, false wake-ups caused by interference signals or invalid signals are reduced, and the stability of the car smart key operation is improved.

[0046] Please refer to it again. Figure 2 The wake-up circuit also includes: a fifth capacitor C5, one end of which is electrically connected to the third control chip U3, and the other end of which is grounded.

[0047] Specifically, one end of the fifth capacitor C5 is connected to the VDD terminal of the third control chip U3, and the other end is grounded to filter the power supply. At the same time, when the power supply voltage fluctuates, the fifth capacitor C5 can temporarily store charge, provide instantaneous current, and stabilize the power supply voltage.

[0048] Please refer to it again. Figure 2 The low-frequency receiving module 10 also includes a second resistor R4, one end of which is electrically connected to the second control chip U2, and the other end of which is electrically connected to the third control chip U3.

[0049] Specifically, one end of the second resistor R4 is electrically connected to the DAT terminal of the second control chip U2, and the other end of the second resistor R4 is electrically connected to the fifth CPIO terminal of the third control chip U3. This limits the current during signal transmission. When a signal is output from the DAT terminal of the second control chip U2, the second resistor R4 limits the current magnitude to prevent excessive current from damaging the input terminal of the third control chip U3. Simultaneously, the second resistor R4 also stabilizes the signal; during signal transmission, it absorbs high-frequency noise, ensuring stable signal transmission.

[0050] Please refer to it again. Figure 2 The low-frequency receiving module 10 also includes a third resistor R5, one end of which is electrically connected to the second control chip U2, and the other end of which is electrically connected to the third control chip U3.

[0051] Specifically, one end of the third resistor R5 is electrically connected to the WAKE terminal of the second control chip U2, and the other end of the third resistor R5 is electrically connected to the fourth CPIO terminal of the third control chip U3. This prevents excessive current from damaging the input terminal of the third control chip U3, ensuring the safe operation of the third control chip U3. Furthermore, the third resistor R5 can limit the current, ensuring that the signal remains stable during transmission and avoiding signal distortion.

[0052] Secondly, please refer to Figure 3 This utility model proposes a handheld terminal, including: the signal processing circuit described above.

[0053] Specifically, the signal processing circuit is applied to the handheld terminal, so the beneficial effects of the handheld terminal are the same as those of the signal processing circuit.

[0054] Compared with existing technologies, the signal processing circuit proposed in this invention for automotive smart keys ensures that when the smart key is in standby mode, the first control chip U1 remains in a dormant state, with only the low-frequency receiving module 10 and the wake-up circuit operating. The power consumption of the low-frequency receiving module 10 and the wake-up circuit is lower than that of the first control chip U1, thus reducing the standby power consumption of the key and extending the battery life of the smart key. Furthermore, the combined processing of the low-frequency signal by the low-frequency receiving module 10 and the judgment of the low-frequency received signal by the wake-up circuit ensures that only a valid wake-up signal can wake up the first control chip U1, preventing false wake-ups and improving the reliability and stability of the automotive smart key system.

[0055] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A signal processing circuit, characterized in that, include: The low-frequency receiving module and the processing module are provided. The output terminal of the low-frequency receiving module is electrically connected to the processing module. The processing module includes a wake-up circuit and a first control chip. The first control chip is configured to receive a wake-up signal sent by the wake-up circuit, so that the first control chip switches from a sleep state to a working state.

2. The signal processing circuit according to claim 1, characterized in that, The low-frequency receiving module includes a three-dimensional inductor, a resonant capacitor unit, and a second control chip. The output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the resonant capacitor unit is connected in parallel between the output terminal of the three-dimensional inductor and the second control chip, and the other end of the resonant capacitor unit is grounded.

3. The signal processing circuit according to claim 2, characterized in that, The resonant capacitor unit includes a first resonant capacitor circuit, a second resonant capacitor circuit, and a third resonant capacitor circuit. The Z-axis output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the first resonant capacitor circuit is connected in parallel between the Z-axis output terminal of the three-dimensional inductor and the second control chip, and the other end of the first resonant capacitor circuit is grounded. The X-axis output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the second resonant capacitor circuit is connected in parallel between the X-axis output terminal of the three-dimensional inductor and the second control chip, and the other end of the second resonant capacitor circuit is grounded. The Y-axis output terminal of the three-dimensional inductor is electrically connected to the second control chip. One end of the third resonant capacitor circuit is connected in parallel between the Y-axis output terminal of the three-dimensional inductor and the second control chip, and the other end of the third resonant capacitor circuit is grounded.

4. The signal processing circuit according to claim 3, characterized in that, The first resonant capacitor circuit, the second resonant capacitor circuit, and the third resonant capacitor circuit have the same structure. The first resonant capacitor circuit includes a first capacitor, a second capacitor, and a third capacitor. One end of the first capacitor, the second capacitor, and the third capacitor are all connected in parallel between the Z-axis output terminal of the three-dimensional inductor and the second control chip. The other end of the first capacitor, the second capacitor, and the third capacitor are connected in parallel and then grounded.

5. The signal processing circuit according to claim 2, characterized in that, The low-frequency receiving module further includes a fourth capacitor, one end of which is electrically connected to the second control chip, and the other end of which is grounded.

6. The signal processing circuit according to claim 2, characterized in that, The wake-up circuit includes a third control chip, the input terminal of which is connected to the output terminal of the second control chip, and the output terminal of which is connected to the first control chip.

7. The signal processing circuit according to claim 6, characterized in that, The wake-up circuit further includes a fifth capacitor, one end of which is electrically connected to the third control chip, and the other end of which is grounded.

8. The signal processing circuit according to claim 6, characterized in that, The low-frequency receiving module further includes a second resistor, one end of which is electrically connected to the second control chip, and the other end of which is electrically connected to the third control chip.

9. The signal processing circuit according to claim 6, characterized in that, The low-frequency receiving module further includes a third resistor, one end of which is electrically connected to the second control chip, and the other end of which is electrically connected to the third control chip.

10. A handheld terminal, characterized in that, include: The signal processing circuit as described in any one of claims 1 to 9.

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