Control circuit of heating pad, heating system of automobile interior part and vehicle
Patent Information
- Application Number
- CN202522539010.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-10-13
- Estimated Expiration
- 2035-11-28
AI Technical Summary
[0005]本申请的目的在于，针对上述现有技术中的不足，提供一种加热垫的控制电路、汽车室内饰件加热系统及车辆，用以解决现有技术中电磁辐射导致的加热系统的控制精度低且可靠性差的问题
[0016]与现有技术相比，采用上述技术方案所产生的有益效果在于：本申请提供的加热垫的控制电路，通过控制芯片输出占空比可调的PWM电压信号，并经由π形滤波电路滤波后，控制开关器件的缓开启与缓关断过程，实现了对加热垫电流的软切换，降低了开关过程中电流与电压的突变速率，从而有效抑制了因阶跃信号引起的高频电磁辐射。因此，该方案从根本上缓解了现有技术中因电磁辐射干扰导致的加热系统控制精度低、可靠性差的问题，提升了整车电磁兼容性的性能，同时增强了加热系统的稳定性和使用寿命，进一步改善了车辆的乘坐舒适性与安全性。
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Figure CN224852370U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of heating device technology, and in particular to a control circuit for a heating pad, a heating system for automotive interior trim, and a vehicle. Background Technology
[0002] With the increasing demands for automotive comfort, heated seats and steering wheels have become common features in vehicles, used to quickly raise the temperature of contact surfaces in cold environments and improve the driving experience. To achieve precise temperature control and energy efficiency, highly efficient control circuits are typically required to regulate the power output of the heating pads, ensuring a stable and reliable heating process.
[0003] Currently, common automotive seat or steering wheel heating control circuits use pulse-width modulation (PWM) technology for temperature regulation. Specifically, the control chip outputs a PWM signal with a fixed duty cycle, which directly controls the on / off state of the heating pad circuit through switching devices to adjust the average power of the heating pad and thus maintain the set temperature. Although this hard-switching method has a simple structure, the current and voltage on the heating pad undergo a sharp jump at the moment the switching devices are turned on and off, resulting in extremely high voltage and current change rates.
[0004] Therefore, the existing technology has significant drawbacks: the sudden changes in current and voltage during the switching process resemble step signals, with a wide spectral composition including numerous high-frequency harmonics, leading to strong electromagnetic radiation. This causes electromagnetic interference to electronic equipment inside and around the vehicle, affecting the overall vehicle's electromagnetic compatibility performance. Furthermore, this interference reduces the control accuracy and reliability of the heating system. Therefore, a heating control scheme that can effectively suppress electromagnetic radiation is urgently needed. Summary of the Invention
[0005] The purpose of this application is to address the shortcomings of the prior art by providing a control circuit for a heating pad, a heating system for automotive interior trim, and a vehicle, thereby solving the problems of low control accuracy and poor reliability of the heating system caused by electromagnetic radiation in the prior art.
[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a control circuit for a heating pad, wherein the heating pad is a car seat heating pad and / or a steering wheel heating pad, and the control circuit includes: a control chip, a π-shaped filter circuit, and a switching device; The control chip is used to output a PWM voltage signal with an adjustable duty cycle; The input terminal of the π-shaped filter circuit is connected to the signal output terminal of the control chip, and is used to filter the PWM voltage signal to obtain the filtered voltage signal. The control terminal of the switching device is connected to the output terminal of the π-shaped filter circuit, the input terminal of the switching device is connected to the power supply through the heating pad, and the output terminal of the switching device is grounded. In response to the filtered voltage signal being greater than the turn-on threshold voltage of the switching device, the switching device is turned on, so that the power supply powers the heating pad, or... In response to the filtered voltage signal not being greater than the switching threshold voltage of the switching device, the switching device is turned off so that the power supply cannot supply power to the heating pad.
[0007] In one possible implementation, the π-shaped filter circuit includes: a resistor, a first capacitor, and a second capacitor; One end of the resistor is the input terminal of the π-shaped filter circuit, and one end of the resistor is also connected to one end of the first capacitor; The other end of the resistor is the output terminal of the π-shaped filter circuit, and one end of the resistor is also connected to one end of the second capacitor; The output terminal of the first capacitor and the other terminal of the second capacitor are both grounded.
[0008] In one possible implementation, the capacitance value of the first capacitor is equal to the capacitance value of the second capacitor.
[0009] In one possible implementation, the switching device includes a metal-oxide-semiconductor field-effect transistor; The gate of the metal-oxide-semiconductor field-effect transistor is the control terminal of the switching device, the source of the metal-oxide-semiconductor field-effect transistor is the input terminal of the switching device, and the drain of the metal-oxide-semiconductor field-effect transistor is the output terminal of the switching device.
[0010] In one possible implementation, the switching device is one of a MOSFET transistor, an NPN transistor, and a PNP transistor.
[0011] In one possible implementation, the control chip is a transistor output programmable logic controller or a single-chip microcomputer.
[0012] In one possible implementation, the control chip integrates a signal generation module; The signal generation module is configured to generate a control sequence so that the control chip outputs a PWM voltage signal with an adjustable duty cycle. The duty cycle of the PWM voltage signal gradually increases during the transition from low to high level, and / or gradually decreases during the transition from high to low level.
[0013] Secondly, this application provides a heating system for automotive interior trim, including a control circuit for the heating pad described in any of the first aspects, the heating pad itself, and a power supply.
[0014] In one possible implementation, the heating pad is provided with heating wires, and the heating pad is a car seat heating pad and / or a steering wheel heating pad; The car seat heating pad is used to install on the car seat, and the steering wheel heating pad is wrapped around the outer surface of the car steering wheel.
[0015] Thirdly, this application provides a vehicle including the automotive interior trim heating system described in any of the second aspects.
[0016] Compared with existing technologies, the beneficial effects of adopting the above technical solution are as follows: The control circuit of the heating pad provided in this application outputs a PWM voltage signal with an adjustable duty cycle through a control chip. After being filtered by a π-shaped filter circuit, it controls the soft-switching process of the switching device, realizing soft switching of the heating pad current and reducing the rate of change of current and voltage during the switching process. This effectively suppresses high-frequency electromagnetic radiation caused by step signals. Therefore, this solution fundamentally alleviates the problems of low control accuracy and poor reliability of the heating system caused by electromagnetic radiation interference in existing technologies, improves the electromagnetic compatibility performance of the entire vehicle, enhances the stability and service life of the heating system, and further improves the ride comfort and safety of the vehicle.
[0017] These or other aspects of this application will become more apparent from the description of the following embodiments. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the control circuit for a heating pad provided in an embodiment of this application; Figure 2 This is a schematic diagram of the control circuit for another heating pad provided in an embodiment of this application.
[0020] Reference numerals: 11 - Control chip; 12 - π-shaped filter circuit; 13 - Switching device; 14 - Heating pad; 121 - Resistor; 122 - First capacitor; 123 - Second capacitor; 131 - Metal-oxide-semiconductor field-effect transistor. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0022] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0024] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this application 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 application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0025] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0026] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Example 1
[0027] Please refer to Figure 1 This embodiment provides a control circuit for a heating pad 14, which is a car seat heating pad and / or a steering wheel heating pad. The structure of the control circuit can be as follows: the control circuit includes a control chip 11, a π-shaped filter circuit 12, and a switching device 13. These components work together to achieve precise control of the heating pad 14 while suppressing electromagnetic radiation.
[0028] Specifically: the control chip 11 is used to output a PWM voltage signal with an adjustable duty cycle; the input terminal of the π-shaped filter circuit 12 is connected to the signal output terminal of the control chip 11, and is used to filter the PWM voltage signal to obtain a filtered voltage signal; the control terminal of the switching device 13 is connected to the output terminal of the π-shaped filter circuit 12, the input terminal of the switching device 13 is connected to the power supply through the heating pad 14, and the output terminal of the switching device 13 is grounded; in response to the filtered voltage signal being greater than the turn-on threshold voltage of the switching device 13, the switching device 13 is turned on, so that the power supply supplies power to the heating pad 14; or, in response to the filtered voltage signal being less than the turn-on threshold voltage of the switching device 13, the switching device 13 is turned off, so that the power supply cannot supply power to the heating pad 14.
[0029] The aforementioned control chip 11 is used to output a PWM voltage signal with an adjustable duty cycle. This signal adjusts the heating power by adjusting the duty cycle, thereby controlling the heating temperature. The input terminal of the π-shaped filter circuit 12 is connected to the signal output terminal of the control chip 11 and is used to filter the PWM voltage signal. After filtering, a smooth voltage signal is obtained, which can reduce high-frequency noise in the signal and then be used to control the switching device 13.
[0030] The frequency range of the PWM voltage signal can be between 1kHz and 20kHz, preferably 5kHz, to balance control accuracy and avoid audible noise. The input terminal of the π-shaped filter circuit 12 can be directly connected to the signal output terminal of the control chip 11 through copper foil traces on the printed circuit board. The π-shaped filter circuit 12 is used to filter the PWM voltage signal containing high-frequency components and convert it into a DC voltage signal with smooth amplitude variation. The switching device 13 is connected to the vehicle power supply (such as a 12V or 24V battery) through the heating wire inside the heating pad 14. Its output terminal (drain / collector) is directly grounded.
[0031] In this embodiment, the control chip 11 outputs a PWM signal with an adjustable duty cycle, which is then filtered by the π-shaped filter circuit 12 to generate a slowly changing voltage signal to control the conduction and turn-off process of the switching device 13. This causes the impedance of the switching device 13 to change slowly from high to low when it is turned on, and to change slowly from low to high when it is turned off, thus realizing soft switching operation. Soft switching reduces the rate of change of current and voltage, and reduces the high-frequency electromagnetic radiation generated by the step signal, thereby solving the problem of low control accuracy and poor reliability of the heating system caused by electromagnetic radiation interference in the prior art, improving the electromagnetic compatibility of the whole vehicle, and enhancing the stability and life of the heating system.
[0032] In one possible implementation, the π-shaped filter circuit 12 includes: a resistor 121, a first capacitor 122, and a second capacitor 123; One end of the resistor 121 is the input terminal of the π-shaped filter circuit 12, and one end of the resistor 121 is also connected to one end of the first capacitor 122. The other end of the resistor 121 is the output terminal of the π-shaped filter circuit 12, and one end of the resistor 121 is also connected to one end of the second capacitor 123. The output terminal of the first capacitor 122 and the other terminal of the second capacitor 123 are both grounded.
[0033] In practical applications, the component values of the π-shaped filter circuit 12 can be adjusted according to the specific application to match the electrical characteristics of different heating pads 14. Specifically, the resistance value of resistor 121 is typically between 1kΩ and 10kΩ, for example, 4.7kΩ; the capacitance values of the first capacitor 122 and the second capacitor 123 are typically between 0.1μF and 10μF, for example, both can be 1μF ceramic capacitors or tantalum capacitors. When the structure of the π-shaped filter circuit 12 is symmetrical, the low-pass filter formed by this structure can effectively filter out high-frequency components in the PWM signal and generate a gradually rising and falling voltage waveform.
[0034] The π-shaped filter circuit 12 constitutes a second-order low-pass filter. Its cutoff frequency is determined by the values of resistor 121 and capacitor. Preferably, its cutoff frequency is designed to be much lower than the fundamental frequency of the PWM signal (e.g., 1 / 10) in order to effectively filter out the switching frequency and its harmonics, thereby obtaining a gradually rising and falling control voltage at the output.
[0035] In a preferred embodiment, the capacitance value of the first capacitor 122 is equal to the capacitance value of the second capacitor 123, for example, both are 1μF, so that symmetrical filtering characteristics can be obtained.
[0036] However, those skilled in the art will understand that, depending on the size of the gate capacitance of the switching device 13 and the specific requirements for the rise / fall speed, the capacitance values of the first capacitor 122 and the second capacitor 123 may not be equal. For example, C1 may be 2.2 μF and C2 may be 0.47 μF, to achieve an asymmetric filtering effect and meet specific soft-start / soft-stop timing requirements. In other embodiments, the specific values of the capacitors can be calculated and determined based on the type of switching device 13 and circuit parameters (such as response time, load current, etc.) to optimize performance.
[0037] Furthermore, the switching device 13 includes a metal-oxide-semiconductor field-effect transistor 131; The gate of the metal-oxide-semiconductor field-effect transistor 131 is the control terminal of the switching device 13, the source of the metal-oxide-semiconductor field-effect transistor 131 is the input terminal of the switching device 13, and the drain of the metal-oxide-semiconductor field-effect transistor 131 is the output terminal of the switching device 13.
[0038] The turn-on threshold voltage of the switching device 13 is an inherent parameter. For common automotive-grade metal-oxide-semiconductor field-effect transistors 131, this threshold voltage is typically between 2V and 4V.
[0039] Furthermore, the switching device 13 is one of a MOSFET transistor, an NPN transistor, and a PNP transistor.
[0040] Furthermore, the control chip 11 is a transistor output programmable logic controller (PLC) or a single-chip microcomputer. PLCs have strong anti-interference capabilities and are suitable for automotive electrical environments; while single-chip microcomputers are programmable and can implement complex control algorithms, making them equally suitable for automotive environments.
[0041] Furthermore, the control chip 11 integrates a signal generation module; The signal generation module is configured to generate a control sequence so that the control chip 11 outputs a PWM voltage signal with an adjustable duty cycle. The duty cycle of the PWM voltage signal gradually increases during the transition from low to high level, and / or gradually decreases during the transition from high to low level.
[0042] For example, the duty cycle of the PWM voltage signal gradually increases during the transition from a low level to a high level (i.e., the turn-on process), for example, linearly increasing from 10% to 90%; and / or gradually decreases during the transition from a high level to a low level (i.e., the turn-off process), for example, linearly decreasing from 90% to 10%. This "ramp-like" duty cycle change provides technical support for achieving soft switching. This gradual duty cycle further smooths current changes and optimizes the soft-switching effect. Example 2
[0043] In this embodiment, a heating system for automotive interior trim is provided, including a control circuit for the heating pad 14 described in Embodiment 1, the heating pad 14, and a power supply.
[0044] Furthermore, the heating pad 14 is provided with heating wires, and the heating pad 14 is a car seat heating pad and / or a steering wheel heating pad; The car seat heating pad is used to install on the car seat, and the steering wheel heating pad is wrapped around the outer surface of the car steering wheel.
[0045] The heating wire can be made of a high-resistance material, such as a nickel-chromium alloy. When energized, it generates heat, which is conducted to the contact surface through the skin.
[0046] The power source can be a vehicle battery or generator, providing DC voltage, such as 12V or 24V, to power the heating pad 14 via a control circuit.
[0047] This heating system utilizes the control circuit of Embodiment 1 to achieve precise temperature control and electromagnetic radiation suppression of the heating pad 14. When the user activates the heating function, the control chip 11 outputs a PWM signal, which, after filtering, controls the soft switching of the switching device 13, ensuring a smooth change in the current of the heating pad 14 and avoiding sudden current surges. This not only reduces electromagnetic radiation but also improves heating uniformity and response speed, enhancing driving comfort. Simultaneously, due to reduced electromagnetic interference, the system's impact on other electronic devices in the vehicle (such as the radio and sensors) is minimized, improving the overall reliability and safety of the vehicle.
[0048] In other embodiments, the heating pad 14 may integrate a temperature sensor that feeds back a signal to the control chip 11 to achieve closed-loop temperature control, further optimizing energy efficiency and comfort.
[0049] In other embodiments, a fuse or overcurrent protection circuit may be added to the power supply line to enhance system safety.
[0050] The specific structure of the automotive interior trim heating system refers to the embodiment of the control circuit of the heating pad 14 described above. Since the automotive interior trim heating system adopts the technical solutions of all embodiments of the control circuit of the heating pad 14 described above, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here. Example 3
[0051] In this embodiment, a vehicle is provided, including the automotive interior trim heating system described in Embodiment 2.
[0052] It should be understood that the vehicle includes an automotive interior trim heating system, and the automotive interior trim heating system includes a control circuit for the heating pad 14. Therefore, the specific structure of the vehicle can refer to the embodiment of the control circuit for the heating pad 14 described above. Furthermore, since the vehicle adopts the technical solutions of all embodiments of the control circuit for the heating pad 14 described above, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.
[0053] In alternative embodiments, the vehicle may include multiple instances of heating systems, such as providing heating for both the driver's and passenger's seats simultaneously.
[0054] In an alternative embodiment, the heating system in the vehicle can communicate with the vehicle bus, allowing heating settings to be controlled via a central display screen or voice commands.
[0055] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A control circuit for a heating pad, characterized in that, The heating pad is a car seat heating pad and / or a steering wheel heating pad, and the control circuit includes: a control chip (11), a π-shaped filter circuit (12), and a switching device (13); The control chip (11) is used to output a PWM voltage signal with an adjustable duty cycle; The input terminal of the π-shaped filter circuit (12) is connected to the signal output terminal of the control chip (11) to filter the PWM voltage signal and obtain the filtered voltage signal. The control terminal of the switching device (13) is connected to the output terminal of the π-shaped filter circuit (12), the input terminal of the switching device (13) is connected to the power supply through the heating pad (14), and the output terminal of the switching device (13) is grounded. In response to the filtered voltage signal being greater than the turn-on threshold voltage of the switching device (13), the switching device (13) is turned on to supply power to the heating pad (14), or, In response to the filtered voltage signal not being greater than the turn-on threshold voltage of the switching device (13), the switching device (13) is turned off so that the power supply cannot supply power to the heating pad (14).
2. The control circuit for the heating pad according to claim 1, characterized in that, The π-shaped filter circuit (12) includes: a resistor (121), a first capacitor (122), and a second capacitor (123); One end of the resistor (121) is the input terminal of the π-shaped filter circuit (12), and one end of the resistor (121) is also connected to one end of the first capacitor (122); The other end of the resistor (121) is the output terminal of the π-shaped filter circuit (12), and one end of the resistor (121) is also connected to one end of the second capacitor (123); The output terminal of the first capacitor (122) and the other terminal of the second capacitor (123) are both grounded.
3. The control circuit for the heating pad according to claim 2, characterized in that, The capacitance value of the first capacitor (122) is equal to the capacitance value of the second capacitor (123).
4. The control circuit for the heating pad according to any one of claims 1 to 3, characterized in that, The switching device (13) includes a metal-oxide-semiconductor field-effect transistor (131); The gate of the metal-oxide-semiconductor field-effect transistor (131) is the control terminal of the switching device (13), the source of the metal-oxide-semiconductor field-effect transistor (131) is the input terminal of the switching device (13), and the drain of the metal-oxide-semiconductor field-effect transistor (131) is the output terminal of the switching device (13).
5. The control circuit for the heating pad according to any one of claims 1 to 3, characterized in that, The switching device (13) is one of a MOSFET transistor, an NPN transistor, or a PNP transistor.
6. The control circuit for the heating pad according to any one of claims 1 to 3, characterized in that, The control chip (11) is a transistor output programmable logic controller or a single-chip microcomputer.
7. The control circuit for the heating pad according to any one of claims 1 to 3, characterized in that, The control chip (11) integrates a signal generation module; The signal generation module is configured to generate a control sequence so that the control chip (11) outputs a PWM voltage signal with an adjustable duty cycle. The duty cycle of the PWM voltage signal gradually increases during the transition from low to high level, and / or gradually decreases during the transition from high to low level.
8. A heating system for automotive interior trim components, characterized in that, It includes the control circuit of the heating pad according to any one of claims 1-5, the heating pad (14), and the power supply.
9. The automotive interior trim heating system according to claim 8, characterized in that, The heating pad (14) is provided with heating wires, and the heating pad (14) is a car seat heating pad and / or a steering wheel heating pad; The car seat heating pad is used to install on the car seat, and the steering wheel heating pad is wrapped around the outer surface of the car steering wheel.
10. A vehicle, characterized in that, Including the automotive interior trim heating system as described in any one of claims 8 to 9.