A kind of automobile invisible door handle circuit based on PPTC self-restoring fuse and automobile

Abstract

The utility model provides a kind of automobile invisible door handle circuit based on PPTC self-restoring fuse and automobile, and the automobile invisible door handle circuit includes anti-reverse connection circuit, power conversion circuit, MCU, DSP circuit, first temperature sensor NTC1, second temperature sensor NTC2, double color light emitting diode, door handle mechanical lock catch intelligent control module, second self-restoring fuse PPTC2, fourth self-restoring fuse PPTC4, fifth self-restoring fuse PPTC5, sixth self-restoring fuse PPTC6, first MOS switch tube Q1, second MOS switch tube Q2, third MOS switch tube Q3, fourth MOS switch tube Q4, fifth MOS switch tube Q5, sixth MOS switch tube Q6.The utility model has the beneficial effects that: the utility model's automobile invisible door handle circuit is high in reliability, not easy to damage, both energy-saving and can melt ice thawing, and can prevent overvoltage overcurrent protection.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuits, and in particular to a car invisible door handle circuit based on a PPTC self-resetting fuse and a car. Background Technology

[0002] In recent years, with people's pursuit of a beautiful car appearance, various invisible door handle technologies have been designed one after another. Although they are more beautiful and intelligent than the fixed traditional door handles, they also bring many thorny problems and practical bottlenecks in design and production. For example, it is necessary to run power lines and various signal cables to the door handles; it is necessary to design mechanical and electrical control circuits for the automatic pop-up and retraction of the door handles; it is necessary to design a one-button pop-up and retraction of the hidden door handles with the car key; it is necessary to design a facial recognition device that can automatically pop up the door handles when the car owner faces the door handles; it is necessary to design door handles with flashing lights to help the driver identify the relative position of the wheels and the ground from the rearview mirror; it is necessary to design a way for the driver to operate the pop-up door handles from the driver's seat so that others can open the side door to get in the car; at the same time, the driver can control the retraction and pop-up of all door handles with one button from the driver's seat; it is also necessary to design a way to control whether the door handles need to flash lights to indicate their position; there is also a major problem that is easily overlooked by designers: the invisible door handles cannot pop up to open the door when the car is icy; and there are also design problems such as people trapped inside the car being unable to open the door for rescue by people outside the car. The design and implementation of these functional circuits are not complex, but when these circuits malfunction—whether it's a short circuit due to cable breakage, arcing or short circuits caused by cable cracks, or high-voltage crosstalk to low-voltage lines leading to circuit burnout—these problems can be fatal. These issues are all based on the safety, reliability, and lifespan of the vehicle system, and are crucial considerations for manufacturers, affecting product success and market competitiveness. Essentially, they involve real-time monitoring and overcurrent, overtemperature, and overvoltage protection of basic functional circuits. Since each functional circuit is a unit composed of multiple components, the quality of components cannot be 100% consistent, the circuit layout cannot avoid the influence of distributed parameters leading to unpredictable anomalies, and abnormalities such as solder tip short circuits, copper film short circuits, and pin bending short circuits may occur during production. These problems and anomalies are major factors affecting product safety and reliability, and designing various protection circuits is the decisive solution to these issues.In traditional circuit protection schemes, PPTC1~PPTC3 positions are mostly protected by disposable glass fuses or 0Ω resistors, or by using a small section of PCB copper film to replace the disposable fuse, or by using a dedicated automotive fuse to achieve the protection function. However, these are all single-use, and the protection device usually only burns out after the circuit is short-circuited. The first two types of fuses can be manually repaired and replaced, but after the PCB copper film fuse is broken, only professional repair personnel may know how to solve the problem, because they cannot determine the type of fuse that should be used, nor can they analyze the cause of the fuse burning out. This is a very troublesome matter, and it is essentially a hidden danger. In high-requirement designs, each part usually uses a set of MCUs and coordinated electronic circuits for detection and protection control. A small resistor is usually used for current sampling, the sampled signal is sent to an amplifier circuit for amplification, the amplified signal is compared with the signal generated by the reference signal circuit by the MCU calculation and comparison circuit, and the difference or control signal is output. The control signal is amplified to the driving amplitude by an external current-driven amplifier circuit MOSFET. This amplified driving current and voltage are then sent to the execution circuit to complete the opening and closing of the switch latch and control tension mechanism. This switch control is mostly accomplished using contactless MOSFETs, or it may be designed to use relays to switch on and off. However, because the contacts may oxidize, arc, or stick, there are potential problems such as continuous burning of the circuit board or wires. It can be seen that each of these protection function circuits is completed by multiple components. Therefore, such a protection circuit requires dozens or even hundreds of components to complete. Moreover, it cannot be guaranteed that the quality of each component is 100% safe, reliable, and long-lasting. There will always be some components that deteriorate and fail first, leading to product quality problems. Therefore, the more components a product has, the lower its reliability. In addition, the more components there are, the higher the procurement cost, production and debugging cost, the larger the PCB area occupied, the larger the overall product space, the shorter the actual service life, the greater the difficulty of after-sales maintenance, the higher the frequency of returns and exchanges, and so on. When faced with the problem of concealed door handles freezing and failing to pop up in low temperatures or icy weather, the first thought is usually to use dual heating wires to thaw the ice in the gap between the concealed door handles. However, the heating wires become more prone to breakage and fracture due to thermal expansion and contraction caused by the high-frequency vibration and shock in the vehicle environment and hardening at low temperatures. In particular, the connection between the heating wire and the wire may break. Since welding cannot be used, the only option is to use screws to crimp the wires, which is the most unreliable assembly process. This will have a fatal impact on the reliability and safety of opening and closing the door. Moreover, regardless of the heating device used, it requires a large current of several amperes or tens of amperes to generate heat, and it also requires a high-power transistor combined with a heat sink to work properly. This not only results in high power consumption and the possibility of runaway, but also requires a large installation space and high cost, among other problems.Given the aforementioned problems, potential risks, and short lifespan, the design of highly reliable control and drive circuits remains a major bottleneck for manufacturers. Currently, manufacturers either use the aforementioned circuits for control, employ simplified circuits, or omit protection and automatic control circuits to save costs in the market. This significantly reduces their competitive advantage, as consumers prefer cost-effective products. Ideal designs become less than ideal market products; problems can lead to fatal safety issues, unacceptable to users, quality disputes, and severely impacting the manufacturer's reputation and sales. To date, there is no ideal protection circuit solution that combines fewer components, high reliability, durability, energy efficiency, ice / thaw protection, overvoltage and overcurrent protection, and effectively extends the lifespan of the circuits used in automotive hidden door handles. This has been a major challenge for design engineers. Utility Model Content

[0003] To address the problems in existing technologies, this utility model provides a car concealed door handle circuit based on a PPTC self-resetting fuse, including a reverse connection protection circuit, a power conversion circuit, an MCU, a DSP circuit, a first temperature sensor NTC1, a second temperature sensor NTC2, a dual-color LED, a door handle mechanical lock intelligent control module, a second self-resetting fuse PPTC2, a fourth self-resetting fuse PPTC4, a fifth self-resetting fuse PPTC5, a sixth self-resetting fuse PPTC6, a first MOS switch Q1, a second MOS switch Q2, a third MOS switch Q3, a fourth MOS switch Q4, and a fifth MOS switch Q5. OS switch Q5, sixth MOS switch Q6, the reverse connection protection circuit output terminal is connected to the power conversion circuit input terminal, the power conversion circuit output terminal is connected to the MCU and the DSP circuit respectively, the MCU is connected to the DSP circuit, the first temperature sensor NTC1 and the second temperature sensor NTC2 respectively, one end of the second self-resetting fuse PPTC2 is connected to the reverse connection protection circuit output terminal and the power conversion circuit input terminal respectively, the fourth MOS switch Q4, fifth MOS switch Q5, sixth MOS switch Q6, first MOS switch Q1, the... The drains of the second MOS switch Q2 and the third MOS switch Q3 are connected in parallel and together to the other end of the second resettable fuse PPTC2; the gates of the fourth MOS switch Q4, the fifth MOS switch Q5, the sixth MOS switch Q6, the first MOS switch Q1, the second MOS switch Q2, and the third MOS switch Q3 are respectively connected to the DSP circuit; the sources of the fourth MOS switch Q4, the fifth MOS switch Q5, and the sixth MOS switch Q6 are respectively connected in series to the fourth resettable fuse PPTC4 and the fifth resettable fuse. PPTC5, the sixth resettable fuse PPTC6, the fourth resettable fuse PPTC4, the fifth resettable fuse PPTC5, and the sixth resettable fuse PPTC6 are connected in parallel at their other ends and are connected together to the output terminal of the reverse connection protection circuit, the input terminal of the power conversion circuit, the door handle mechanical latch intelligent control module, and the cathode of the dual-color light-emitting diode; the two anodes of the dual-color light-emitting diode are respectively connected to the sources of the second MOS switch Q2 and the third MOS switch Q3; the door handle mechanical latch intelligent control module is also connected to the source of the first MOS switch Q1 and the DSP circuit.

[0004] As a further improvement of this utility model, the fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are polymer positive temperature coefficient type thermal transient resistors.

[0005] As a further improvement of this utility model, the fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are rectangular in shape, with dimensions of 40.0 mm in length, 6.0 mm in width, and 2.0 mm in thickness. The fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 have a withstand voltage greater than 600V, a normal operating current of 30mA, a withstand impulse current of up to 150A, and a resistance value in the range of 30Ω to 40Ω.

[0006] As a further improvement of this utility model, the fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are all covered with a high-voltage-resistant thermally conductive insulating film.

[0007] As a further improvement of this utility model, the reverse connection protection circuit includes a first self-resetting fuse PPTC1, a varistor RV, a bridge rectifier diode, and a filter capacitor C1. The input terminal of the bridge rectifier diode is connected in parallel with the varistor RV, and the output terminal of the bridge rectifier diode is connected in parallel with the filter capacitor C1. One end of the first self-resetting fuse PPTC1 is connected to the positive terminal of the DC 12V power supply, and the other end of the first self-resetting fuse PPTC1 is connected to the input terminal of the bridge rectifier diode.

[0008] As a further improvement of this utility model, the power conversion circuit is a DC to DC 24V to 5.0V and 3.3V conversion circuit.

[0009] As a further improvement of this utility model, the car invisible door handle circuit also includes a face recognition camera control circuit and a memory circuit. The face recognition camera control circuit is connected to the DSP circuit, and the memory circuit is connected to the MCU.

[0010] As a further improvement of this utility model, the automotive invisible door handle circuit also includes a gate protection circuit, wherein one of the gate protection circuits is connected in series between the gates of the fourth MOS switch Q4, the sixth MOS switch Q6, the first MOS switch Q1, the second MOS switch Q2, and the third MOS switch Q3 and the DSP circuit.

[0011] As a further improvement of this utility model, the gate protection circuit of the fourth MOS switch Q4 includes a first resistor R1, a second resistor R2, and a fifth diode D5. The second resistor R2 and the fifth diode D5 are connected in series to form a first branch. The first resistor R1 is connected in parallel across the two ends of the first branch. One end of the first branch is connected to the gate of the fourth MOS switch Q4, and the other end of the first branch is connected to the DSP circuit. The gate protection circuit of the sixth MOS switch Q6 includes a ninth resistor R9, a tenth resistor R10, and a ninth diode D9. The tenth resistor R10 and the ninth diode D9 are connected in series to form a second branch. The ninth resistor R9 is connected in parallel across the two ends of the second branch. One end of the second branch is connected to the gate of the sixth MOS switch Q6, and the other end of the second branch is connected to the DSP circuit. The gate protection circuit of the first MOS switch Q1 includes a seventh resistor R7, an eighth resistor R8, and an eighth diode D8. The eighth resistor R8 and the eighth diode D8 are connected in series to form a third branch. The seventh resistor R7 is connected in parallel across the two ends of the third branch. One end of the third branch is connected to the gate of the first MOS switch Q1, and the other end of the third branch is connected to the DSP circuit. The gate protection circuit of the second MOS switch Q2 includes a third resistor R3, a fourth resistor R4, and a sixth diode D6. The fourth resistor R4 and the sixth diode D6 are connected in series to form a fourth branch. The third resistor R3 is connected in parallel across the two ends of the fourth branch. One end of the fourth branch is connected to the gate of the second MOS switch Q2, and the other end of the fourth branch is connected to the DSP circuit. The gate protection circuit of the third MOS switch Q3 includes a fifth resistor R5, a sixth resistor R6, and a seventh diode D7. The fifth resistor R5 and the seventh diode D7 are connected in series to form a fifth branch. The sixth resistor R6 is connected in parallel across the two ends of the fifth branch. One end of the fifth branch is connected to the gate of the third MOS switch Q3, and the other end of the fifth branch is connected to the DSP circuit.

[0012] This utility model also discloses an automobile, including the automobile invisible door handle circuit described in this utility model. The fourth self-resetting fuse PPTC4 is embedded in the transverse space of the central slot of the H-shaped hard alloy skeleton of the invisible door handle and is fastened by a sheet spring. The first temperature sensor NTC1, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are installed on the inner wall of the invisible door handle slot.

[0013] The beneficial effects of this utility model are: 1. The automotive concealed door handle circuit of this utility model has high reliability, is not easily damaged, is energy-saving and can melt and thaw ice, and can also prevent overvoltage and overcurrent protection, effectively extending the product circuit life in the above-mentioned automotive concealed door handle application field; 2. There are currently no similar products on the market, and it can only be compared with a single-chip computer circuit system with similar functions but more complex. However, its single-chip circuit is complex, costly, has a high failure rate, and is difficult to produce and debug, which has become an unavoidable problem for manufacturers and design engineers. It can be seen that the automotive concealed door handle circuit of this utility model can make related automotive products and equipment more stable, safe, reliable, low-cost, and easy to apply, and can be mass-produced and launched on the market. Attached Figure Description

[0014] Figure 1 This is a circuit diagram illustrating the principle of the concealed door handle circuit for automobiles according to this utility model. Figure 2 This is a structural diagram of a specially designed self-resetting fuse. Detailed Implementation

[0015] The present invention discloses a car invisible door handle circuit based on a PPTC self-resetting fuse, which is mainly used in invisible door handle systems of various fuel and new energy vehicles. Compared with traditional circuits, it has lower cost, higher reliability, longer lifespan, and does not need to be replaced for life.

[0016] like Figure 1As shown, this utility model discloses a car concealed door handle circuit based on a PPTC self-resetting fuse, including a reverse connection protection circuit, a power conversion circuit, an MCU, a DSP circuit, a first temperature sensor NTC1, a second temperature sensor NTC2, a dual-color light-emitting diode, a door handle mechanical lock intelligent control module, a second self-resetting fuse PPTC2, a fourth self-resetting fuse PPTC4, a fifth self-resetting fuse PPTC5, a sixth self-resetting fuse PPTC6, a first MOS switch Q1, a second MOS switch Q2, a third MOS switch Q3, a fourth MOS switch Q4, and a fifth MOS switch Q5. The sixth MOS switch Q6 is connected to the reverse connection protection circuit output terminal, which is connected to the power conversion circuit input terminal. The power conversion circuit output terminal is connected to the MCU and the DSP circuit respectively. The MCU is connected to the DSP circuit, the first temperature sensor NTC1, and the second temperature sensor NTC2 respectively. One end of the second resettable fuse PPTC2 is connected to the reverse connection protection circuit output terminal and the power conversion circuit input terminal respectively. The fourth MOS switch Q4, the fifth MOS switch Q5, the sixth MOS switch Q6, the first MOS switch Q1, and the second MOS switch Q6 are also connected. The drains of the first MOS switch Q2 and the third MOS switch Q3 are connected in parallel and together connected to the other end of the second resettable fuse PPTC2; the gates of the fourth MOS switch Q4, the fifth MOS switch Q5, the sixth MOS switch Q6, the first MOS switch Q1, the second MOS switch Q2, and the third MOS switch Q3 are respectively connected to the DSP circuit; the sources of the fourth MOS switch Q4, the fifth MOS switch Q5, and the sixth MOS switch Q6 are respectively connected in series with the fourth resettable fuse PPTC4 and the fifth resettable fuse PPTC2. TC5, the sixth resettable fuse PPTC6, the fourth resettable fuse PPTC4, the fifth resettable fuse PPTC5, and the sixth resettable fuse PPTC6 are connected in parallel at their other ends and are connected together to the output terminal of the reverse connection protection circuit, the input terminal of the power conversion circuit, the door handle mechanical latch intelligent control module, and the cathode of the dual-color light-emitting diode; the two anodes of the dual-color light-emitting diode are respectively connected to the sources of the second MOS switch Q2 and the third MOS switch Q3; the door handle mechanical latch intelligent control module is also connected to the source of the first MOS switch Q1 and the DSP circuit.

[0017] The reverse connection protection circuit includes a first resettable fuse PPTC1, a varistor RV, a bridge rectifier diode, and a filter capacitor C1. The input terminal of the bridge rectifier diode is connected in parallel with the varistor RV, and the output terminal of the bridge rectifier diode is connected in parallel with the filter capacitor C1. One end of the first resettable fuse PPTC1 is connected to the positive terminal of a DC 12V power supply, and the other end of the first resettable fuse PPTC1 is connected to the input terminal of the bridge rectifier diode.

[0018] The car's invisible door handle circuit also includes a face recognition camera circuit and a memory circuit. The face recognition camera circuit is connected to the DSP circuit, and the memory circuit is connected to the MCU.

[0019] The automotive concealed door handle circuit also includes a gate protection circuit, wherein each of the fourth MOS switch Q4, the sixth MOS switch Q6, the first MOS switch Q1, the second MOS switch Q2, and the third MOS switch Q3 is connected in series with the DSP circuit.

[0020] The gate protection circuit of the fourth MOS switch Q4 includes a first resistor R1, a second resistor R2, and a fifth diode D5. The second resistor R2 and the fifth diode D5 are connected in series to form a first branch. The first resistor R1 is connected in parallel across the two ends of the first branch. One end of the first branch is connected to the gate of the fourth MOS switch Q4, and the other end of the first branch is connected to the DSP circuit. The gate protection circuit of the sixth MOS switch Q6 includes a ninth resistor R9, a tenth resistor R10, and a ninth diode D9. The tenth resistor R10 and the ninth diode D9 are connected in series to form a second branch. The ninth resistor R9 is connected in parallel across the two ends of the second branch. One end of the second branch is connected to the gate of the sixth MOS switch Q6, and the other end of the second branch is connected to the DSP circuit. The gate protection circuit of the first MOS switch Q1 includes a seventh resistor R7, an eighth resistor R8, and an eighth diode D8. The eighth resistor R8 and the eighth diode D8 are connected in series to form a third branch. The seventh resistor R7 is connected in parallel across the two ends of the third branch. One end of the third branch is connected to the gate of the first MOS switch Q1, and the other end of the third branch is connected to the DSP circuit. The gate protection circuit of the second MOS switch Q2 includes a third resistor R3, a fourth resistor R4, and a sixth diode D6. The fourth resistor R4 and the sixth diode D6 are connected in series to form a fourth branch. The third resistor R3 is connected in parallel across the two ends of the fourth branch. One end of the fourth branch is connected to the gate of the second MOS switch Q2, and the other end of the fourth branch is connected to the DSP circuit. The gate protection circuit of the third MOS switch Q3 includes a fifth resistor R5, a sixth resistor R6, and a seventh diode D7. The fifth resistor R5 and the seventh diode D7 are connected in series to form a fifth branch. The sixth resistor R6 is connected in parallel across the two ends of the fifth branch. One end of the fifth branch is connected to the gate of the third MOS switch Q3, and the other end of the fifth branch is connected to the DSP circuit.

[0021] The main functions of the automotive concealed door handle circuit based on a PPTC self-resetting fuse of this utility model are as follows: ① Specially designed self-resetting fuses PPTC4~PPTC6 enable rapid defrosting of the concealed door handle after it freezes in low temperatures, solving the problem of the concealed door handle failing to automatically pop out when ice forms around the handle groove in cold weather. ② Self-resetting fuses PPTC1, PPTC2, and PPTC3 provide rapid and timely protection for related circuits in case of overcurrent, short circuit, or grounding short circuit. ③ Self-resetting fuse PPTC1 and varistor RV provide overvoltage protection. Because the electromagnetic environment of automotive circuits is very complex, high voltage can easily be generated due to various reasons, including transient and continuous high voltages, thus requiring overvoltage protection. All of these functions are accomplished by individual components, significantly reducing the number of components, costs, design space, and volume compared to traditional circuit components or modules performing the same function. This also greatly improves the safety, reliability, and lifespan of the device, and solves design and production bottlenecks for manufacturers, enhancing their market competitiveness. All of this utilizes the timely current-limiting protection function of PPTC after overcurrent and short circuits. With the solution of this utility model, regardless of whether the cause is accidental, inevitable, or unintentional human error, the PPTC self-resetting fuse provides timely current limiting and protection. Because it uses surface-mount devices and has a compact design, it not only reduces the number of components used but also significantly improves product safety and reliability, greatly reduces costs, and significantly shrinks the PCB area and space occupied. It also facilitates engineers' design and allows for automated, large-scale production.

[0022] Main features: Door handles are typically housed within a slot, their outer surface flush with the exterior of the car door, and their color may be the same or different (possibly specially designed in shape and color), creating an almost seamless connection. When the concealed door handle is designed to be flush with and the same color as the car door, it is not easily visible, only popping out in a controlled manner when needed. The functional circuitry is characterized by: ① Although the concealed door handle is not easily visible, there is still a small gap. In winter or in environments with temperatures below -5°C or extremely low temperatures, ice will accumulate in this gap, causing the concealed door handle to stick to the slot and preventing it from popping out. The owner will then be unable to open the door or use the vehicle. This invention utilizes a specially designed elongated PPTC4~ The PPTC6 heats up when energized and conducts heat to the inner wall (gap) of the concealed door handle groove, rapidly melting any ice buildup and allowing the door handle to automatically pop out within seconds. Furthermore, when the door handle pops out normally or when the temperature of both the inner wall of the concealed groove and the outer wall of the door handle exceeds +5°C, the specially designed PPTC4-PPTC6 will not heat up. These specially designed heating PPTC4-PPTC6 components are elastic, deformable and bendable in both hot and cold conditions without affecting normal operation, and will not be shattered or broken by strong vibrations. They can operate normally for extended periods under severe vibration conditions, which is a common application scenario in automobiles. Currently known other ceramic heating elements or heating wires will shatter or break due to strong vibrations (especially at the connection point between the heating wire and the lead wire). The specially designed elongated heating elements PPTC4-PPTC6 are easy to install; they simply need to be pressed tightly against the heat-conducting alloy groove using spring clips. The heating temperature can be automatically adjusted between 60-85°C. Heat conduction to the inner surface of the slot and the outer surface of the door handle can reach 30-40℃, rapidly melting ice and allowing the concealed door handle to pop out promptly—this is a unique advantage of this invention. Secondly, the use of single PPTC1-PPTC3 components to replace traditional multi-component circuit systems achieves and completes overcurrent and short-circuit protection for each branch. Thirdly, overvoltage protection and system protection are achieved through the protection of the varistor RV by PPTC1. This also avoids various problems, especially the problem of fire caused by high-current wire burning.

[0023] Topology and composition: The topology consists of a reverse connection protection circuit, DC-to-DC 24V to 5.0V and 3.3V conversion circuits, MCU and DSP circuits, a storage circuit, a first temperature sensor NTC1 and a second temperature detection circuit NTC2, a face recognition camera control circuit, a door handle mechanical lock intelligent control module, self-resetting fuses PPTC4~PPTC6 and MOS switches Q4~Q6, LEDs and switching MOS transistors Q1~Q3, and related circuits. These circuits are divided into two parts installed in different locations: one inside the concealed door handle and the other in an appropriate location inside the car door, connected by flexible ribbon cables. Inside the concealed door handle are the fourth self-resetting fuse PPTC4, an ice-melting heating element, a miniature pinhole camera, the second temperature sensor NTC2, and a dual-color LED marker flash (dual-color light-emitting diode). Other functional components, except for the first temperature sensor NTC1, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 whose heating blocks are installed on the back of the inner wall of the concealed door handle groove, are mounted on a circuit board and fixed in an empty space inside the door or placed in the main control panel of the driver's cab. They are connected to the wiring interface via cables and connected to the corresponding circuits through the wiring interface inside the door handle.

[0024] Working principle: This article focuses on the working principles of circuits directly related to innovation. Other indirectly related circuits and mechanical unlocking due to power failure are presented in block diagrams and are not discussed in detail. The DC12V input voltage from the vehicle power supply powers the subsequent control circuits after passing through the reverse connection protection circuit. The reverse connection protection circuit consists of the first self-resetting fuse PPTC1, RV varistor, D1~D4 rectifier bridge, and filter capacitor C1, etc., and its outputs power the power load and signal processing load respectively. Here, we first discuss the four components and their working principles within the dashed box, including the fourth self-resetting fuse PPTC4, the LED dual-color flashing light (dual-color light-emitting diode), the pinhole camera SX1, and the first temperature sensor NTC1. These components are installed inside the car's hidden door handle. It should be noted that the resettable fuses PPTC4 to PPTC6 are specially made PPTC components used in this invention. They are long and narrow, measuring 40.0 mm in length, 6.0 mm in width, and 2.0 mm in thickness, i.e., 40.0 × 6.0 × 2.0 mm in size. They are high-polymer positive temperature coefficient thermal transient resistors. Because this product is made of polymer resin material, it has high-temperature plasticity and room-temperature deformability. It can be bent within 45° in the flat direction and twisted within 20° in the flat direction without affecting normal operation. Due to its 6.0 mm width, it has high lateral mechanical strength, but it can also be bent slightly at 3° to 5° without affecting its electrical performance and normal operation. The resettable fuses PPTC4 to PPTC6 are all installed in a fixed slot and can be bent and tightened according to the curvature of the slot. The electrical connection is a solder connection, which ensures the reliability of the assembly. Therefore, it can withstand strong vibrations in all directions (up, down, left, right, front, back) without being damaged or broken. It is also not affected by the high-frequency vibrations during long-term use of a car, and its inherent thermal expansion and contraction characteristics prevent low-temperature stiffening and cracking—something other products with heating functions cannot achieve. The fourth self-resetting fuse, PPTC4, is wrapped in a high-pressure-resistant thermally conductive insulating film and installed within the central slot of the H-shaped hard alloy frame in the center of the concealed door handle. It is secured by a leaf spring, and the second temperature sensor, NTC2, is secured to the end of the fourth self-resetting fuse PPTC4 without leads. This sensor detects the heat generated by PPTC4 and the temperature of the H-shaped alloy bracket. After the fourth self-resetting fuse PPTC4 and the second temperature sensor NTC2 are installed, there is a space (hollow) between them and the decorative fasteners on the upper and lower ends of the H-shaped bracket. The H-shaped hard alloy frame is designed and manufactured with an H-shaped horizontal placement during the concealed door handle's construction (e.g., if the H-shaped becomes "..."). (The direction is unclear), meaning the two long sides of H are the decorative strips along the top and bottom outer edges of the concealed door handle, and the inner and outer strips are snap-fitted into the " The two ends of the fuse PPTC4 are normally embedded in the slots, with the outer edges flush with the car door surface and the same color (or a different color). When the fourth resettable fuse PPTC4 heats up, its heat will pass through... The heat is conducted to the outer edges (top and bottom edges) of the door handle, causing the outer edges to heat up and melt ice in the gaps between them, while ensuring the door handle doesn't become too hot to touch. The fourth, fifth, and sixth resettable fuses (PPTC4, PPTC5, and PPTC6) are identical; they can bend with the curvature of the door handle, are vibration-resistant, and will not be damaged by long-term, strong, and frequent vibrations. They differ only in their installation location; their function is the same. The fifth resettable fuse PPTC5 and the sixth resettable fuse PPTC6 are also wrapped with a high-pressure-resistant thermally conductive insulating film and installed and fixed on the back of the inner wall of the door handle groove. There is one on the upper and lower back of the inner wall of the groove. The heat is directly conducted to the groove wall, thereby achieving the purpose of heating and melting ice. Moreover, it is not visible from the groove inward because the invisible groove of the invisible door handle itself is a waterproof integral groove. Similarly, the first temperature sensor NTC1 is installed and fixed on the non-pin end of the fifth resettable fuse PPTC5 or the sixth resettable fuse PPTC6 to detect the temperature of the fifth resettable fuse PPTC5 or the sixth resettable fuse PPTC6 and the inner groove wall. The fourth, fifth, and sixth resettable fuses (PPTC4, PPTC5, and PPTC6) can each withstand voltages up to 600V and surge currents up to 150A. Their resistance ranges from 30Ω to 40Ω. They do not heat up at room temperature (25℃) and maintain a constant resistance at an operating current of 30mA. If the current flowing through the PPTC exceeds 60mA, the PPTC will rapidly heat up, reaching 90℃ in approximately 25 seconds (its internal temperature can reach 130-140℃). Simultaneously, the resistance of the PPTC will increase to the KΩ level to limit the current to approximately 10mA while continuing to heat up, maintaining this state—the overcurrent protection state of the PPTC. If the current is even greater, exceeding three times the 90mA, the PPTC will heat up to 90-100℃ in approximately 8-10 seconds, simultaneously limiting the current to below 10mA and maintaining this high temperature. The resistance and heating states, but the operating state, power-on time, and current magnitude of the fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are controlled by the switching states of the corresponding MOSFETs Q4, Q5, and Q6. The switching states of the MOSFETs are controlled by the MCU's calculation of the temperature values ​​detected by the first temperature sensor NTC1 and the second temperature sensor NTC2, and then output as control signals by the DSP. When the MCU receives a remote control signal from the car key, a door opening control signal from the driver's cab, or a signal from the face camera recognizing the owner's facial features and triggering the pop-up hidden door handle, the MCU will first detect the temperature signals from the first temperature sensor NTC1 and the second temperature sensor NTC2. If the MCU detects a temperature below -5℃ through the first temperature sensor NTC1 and the second temperature sensor NTC2, then...There might be ice buildup in the gap between the concealed door handle and its groove. In this case, the MCU will not output a signal to open the door handle via the DSP. Instead, it will first output a signal to the Q4-Q6 switching transistors to energize the resettable fuses PPTC4-PPTC6, causing them to heat up and melt the ice. This will result in a current flowing from 12V ÷ 30Ω = 0.4A (400mA) to 12V ÷ 40Ω = 0.3A (300mA) through the resettable fuses PPTC4-PPTC6. Therefore, the resettable fuses PPTC4-PPTC6 will receive ten times the 30mA current. The high current (more than 13 times the rated current) causes the resettable fuses PPTC4-PPTC6 to rapidly heat up to 90°C or higher within 1-2 seconds. When the MCU detects the temperature rise to 40°C-50°C via the first temperature sensor NTC1 and the second temperature sensor NTC2, the MCU will issue a command and, through the DSP, turn off the signal output to the MOSFET, causing the resettable fuses PPTC4-PPTC6 to stop heating. However, the internal heat of the PPTC fuses will remain for a few seconds. During this time, the inner wall of the door handle slot and the outer edge of the door handle will simultaneously experience a temperature rise of 20°C-30°C (due to thermal resistance, the PPTC cannot completely conduct heat), causing the ice to melt. If this temperature cannot be maintained and continues to drop to +5°C or below, the DSP will output a switching signal again. Each MOSFET causes the resettable fuses PPTC4-PPTC6 to instantly heat up, and this cycle repeats until the ice melts completely. The temperature of the inner wall of the slot and the outer edge of the door handle rises to about +15°C. At this point, Q4-Q6 are controlled to cut off the current, and at the same time, the DSP output signal controls the Q3 switch to open, triggering mechanical control to pop out the door handle. This process is set to complete in about 5-8 seconds. If the MCU detects a temperature higher than +5°C through NTC1 and NTC2, the MCU will directly output a signal to the MOSFET Q3 to pop out the hidden door handle, which will control the solenoid valve, electromagnet, or related mechanical control motor, etc., and directly pop out the hidden door handle without activating the heating function. The car owner can directly open the driver's side door, and the other doors can be operated by the driver from the driver's side, or set to one-button control or remote control to open all door handles with one button. Temperatures above +5°C are the norm in most cases. Under these conditions, Q4-Q6 and PPTC4-PPTC6 will not operate and no current will flow. The aforementioned switching temperature data is pre-set and stored in memory. The temperature detected by the MCU and the required action signal output are determined by comparing the real-time temperature detection with the preset temperature and action parameters in memory through the internal program to make judgments and output execution command signals. In the block diagram, the LED is installed at one end of the concealed door handle. It is switched to light by Q2 and Q3 and the bias auxiliary circuit, and is installed inside the edge of the door handle through a light guide strip. It can emit light in intermittent spot or intermittent strip pattern, and when this lighting function is activated, it flashes alternately between red and green light.When not in use, the outer surface of the door handle will be completely invisible, meaning there will be no visible trace of any light-emitting or flashing function. This function is so discreet that only the owner is aware of it. It is designed to provide the driver with the vehicle's position information via the rearview mirror, facilitating mirror adjustments and identification of the vehicle's position and wheels while driving. Similarly, the pinhole camera is very small and can be installed at one end of the concealed door handle or inside the door, outside the handle end. Once installed, its small size makes it difficult to detect visually, not only not affecting the car's appearance, but also only effective for owners who have pre-recorded their facial recognition. Anyone without pre-recorded facial recognition will be rendered ineffective. The self-resetting fuses PPTC1-PPTC3 in the block diagram are used for overcurrent and short-circuit high-current protection in power load circuits. The signal processing circuit after the power conversion circuit operates on a low current basis, and both the MCU and DSP chips have on-chip overload protection, which will not be elaborated upon further. The self-resetting fuse PPTC1 mainly performs three protective functions. First, when a continuous large current occurs in the power circuit, and the current in each branch is insufficient to meet the protection conditions of the PPTC1 self-resetting fuse, the large current is collected and flows to the first self-resetting fuse PPTC1. In this case, the first self-resetting fuse PPTC1 provides timely overcurrent protection. Second, large currents that may occur in the power conversion circuit and its directly connected load circuits due to various overcurrent problems also pass through the first self-resetting fuse PPTC1. In this case, the first self-resetting fuse PPTC1 promptly performs its overcurrent and short-circuit protection functions. Third, when the input power line is passively connected or high voltage is introduced due to interference or induction (because the electromagnetic environment inside a car is very complex, such as wire grounding, short circuit with a high-voltage circuit, parallel wiring, or crosstalk high voltage of unknown cause, or flyback high voltage crosstalk from starting and stopping the motor, etc.), the varistor RV will be triggered to conduct instantaneously, generating a large current. This large current may be transient or continuous. If the voltage surge lasts for 1-2 seconds or longer, the varistor RV will burn out, explode, or cause unpredictable catastrophic failures (because RV can only operate transiently, absorbing transient high voltage but not continuous high voltage). In this case, since the first resettable fuse PPTC1 is in front of the varistor RV, the large current flowing through RV will also pass through PPTC1. Therefore, the resistance of PPTC1 will increase instantaneously under these large currents, limiting the current and protecting RV. It is precisely through the protection of RV by PPTC1 that the entire vehicle's electrical system is protected. The second resettable fuse PPTC2 is mainly for the relatively high-power circuit branch it is connected to. When the load circuit connected after PPTC2 experiences a large current for various reasons...For example, MOSFETs or their associated circuits may experience overcurrent or short circuits due to various reasons such as solder bridging during production, copper film connections, bent leads, solder dross or stuck solder balls, component damage, harmonic current generation, and self-excited ringing with large currents, which can affect the protection of the vehicle's power supply. The third type of self-resetting fuse, PPTC3, is mainly designed for the switching drive system of concealed door handles, such as motors or solenoid valve coils. However, it also protects against overcurrent or short circuits caused by various reasons, including cracked insulation varnish on the coil windings of motors and solenoid valves, sparking, or short circuits caused by insulation varnish peeling, as well as overcurrent or short circuits caused by various reasons related to the switching MOSFETs and their associated circuits. These "various reasons" refer to factors such as design and production processes, experimental and testing processes, use and maintenance processes, long-term vibration of the vehicle, the components themselves, sudden resonant overcurrents in the circuit, short circuits during maintenance, and unpredictable overcurrent or short circuits. As can be seen from the above, this concealed door handle control system uses a PPTC resettable fuse, and this function can be accomplished by a single component. In contrast, traditional solutions that achieve the same protection function require an additional MCU and supporting circuitry. This includes a large circuit assembly consisting of a sampling circuit, a sample amplification circuit, a circuit comparing the amplified signal with a reference source, amplifying the comparison result signal again, sending it to the control execution circuit, and driving the MOSFET switch to change its operating state. The PPTC resettable fuse, a single component, achieves the same function with only one percent of the components required in such a large circuit assembly. The PPTC resettable fuse has a current rating of over 100A, which is undeniable, as none of the components used in the aforementioned traditional circuit system can meet this 100A current rating. In a system with numerous components providing the same protection function, it's impossible to ensure 100% reliability for every single component. Therefore, the reliability of the PPTC resettable fuse is undoubtedly the best option currently available. Not only does it require fewer components (one component performs the function of multiple circuits), but its advantages in terms of procurement costs, R&D and production costs, sales and service costs, PCB area requirements, and component installation space requirements are also practically tangible and unparalleled. The mechanism by which the aforementioned PPTC resettable fuse provides overcurrent protection is as follows: When a large current flows through the PPTC resettable fuse, the internal temperature of the PPTC rises. Within the set temperature range (-40℃ to +85℃), its resistance value changes within a very small range without affecting the normal operation of the circuit. When the PPTC resettable fuse heats up due to the large current, it undergoes thermal expansion, causing most of the conductive links inside the PPTC resettable fuse to break. The resistance value of the PPTC resettable fuse suddenly increases, thus completing the current limiting protection. When the power is disconnected, the temperature of the PPTC resettable fuse decreases, and the PPTC contracts due to cooling. The previously broken conductive links are reconnected, restoring the initial low resistance value.It is reusable. However, compared to the trigger conduction of the varistor RV (similar to a short circuit), its resistance value is several times, tens of times, or even hundreds of times that of RV when it is conducting. Moreover, as a large current passes through, the resistance value of PPTC increases to limit the current, so the continuous large current will not cause RV to burn out or explode when triggering a short circuit. This protects the varistor RV, and the protection of the varistor RV achieves the purpose of system circuit protection, greatly extending the service life of the varistor RV, and ultimately greatly extending the service life of the entire circuit system. As a result, it can not only provide long-term overvoltage protection for the varistor RV, but also protect against both intentional and unintentional short circuits during the production process. This ensures that the circuit system will not burn out due to short circuits or component damage after a short circuit occurs, and will not cause serious fires.

[0025] The use of this advanced self-resetting fuse (PPTC) not only simplifies the overall circuit design but also solves the problems of component damage and short-circuit current limiting protection. It also provides both human-caused and non-human-caused short-circuit protection for the aforementioned circuit system, preventing circuit burnout and serious fires caused by short circuits. Furthermore, it solves design challenges for equipment manufacturers and engineers, using minimal components, occupying little space, reducing cost, and increasing reliability. This makes products safer, simpler, and easier to design, providing genuine safety assurance for related equipment and directly enhancing the manufacturer's market competitiveness.

[0026] Component selection: 1. The first self-resetting fuse PPTC1, the second self-resetting fuse PPTC2, and the third self-resetting fuse PPTC3 are self-resetting fuses used for overcurrent and short-circuit protection. Use special surface-mount nonlinear thermistors or through-hole PPTC thermistors that are mounted close to the PCB board. The current should be selected at the normal operating current value or slightly higher by 10%. The current of different branches should be based on actual measurement. The voltage should be selected with a withstand voltage of 250V or 600V.

[0027] 2. Selection of the fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 Figure 2 A specially made PPTC resistor is sufficient, with electrical parameters as described in the working principle description. This is also a custom-made product. Specifically, it is a polymer positive temperature coefficient type thermal transient resistor with dimensions of 40.0×6.0×2.0 mm, a withstand voltage greater than 600V, a normal operating current of 30mA, an impulse current of up to 150A, and a resistance value in the range of 30Ω to 40Ω.

[0028] 3. Selection of varistor RV: Select a surface-mount high-power or high-joule RV or VDE varistor with a voltage greater than 24V. There are no other special requirements.

[0029] This utility model also discloses an automobile, including the automobile invisible door handle circuit of this utility model. The fourth self-resetting fuse PPTC4 is embedded in the transverse space of the central slot of the H-shaped hard alloy skeleton of the invisible door handle and is fastened by a sheet spring. The first temperature sensor NTC1, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are installed on the inner wall of the invisible door handle slot.

[0030] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. A circuit for an automotive concealed door handle based on a PPTC self-resetting fuse, characterized in that: The circuit includes a reverse connection protection circuit, a power conversion circuit, an MCU, a DSP circuit, a first temperature sensor NTC1, a second temperature sensor NTC2, a dual-color LED, a door handle mechanical lock smart control module, a second resettable fuse PPTC2, a fourth resettable fuse PPTC4, a fifth resettable fuse PPTC5, a sixth resettable fuse PPTC6, a first MOS switch Q1, a second MOS switch Q2, a third MOS switch Q3, a fourth MOS switch Q4, a fifth MOS switch Q5, and a sixth MOS switch Q6. The output terminal of the reverse connection protection circuit is connected to the power conversion circuit. The input terminal of the power conversion circuit is connected, and the output terminal of the power conversion circuit is connected to the MCU and the DSP circuit respectively. The MCU is connected to the DSP circuit, the first temperature sensor NTC1, and the second temperature sensor NTC2 respectively. One end of the second resettable fuse PPTC2 is connected to the output terminal of the reverse connection protection circuit and the input terminal of the power conversion circuit respectively. The drains of the fourth MOS switch Q4, the fifth MOS switch Q5, the sixth MOS switch Q6, the first MOS switch Q1, the second MOS switch Q2, and the third MOS switch Q3 are connected in parallel and together to the other end of the second resettable fuse PPTC2. The gates of the fourth MOS switch Q4, the fifth MOS switch Q5, the sixth MOS switch Q6, the first MOS switch Q1, the second MOS switch Q2, and the third MOS switch Q3 are respectively connected to the DSP circuit. The sources of the fourth MOS switch Q4, the fifth MOS switch Q5, and the sixth MOS switch Q6 are respectively connected in series with the fourth resettable fuse PPTC4, the fifth resettable fuse PPTC5, and the sixth resettable fuse Q6. The reset fuse PPTC6, the fourth reset fuse PPTC4, the fifth reset fuse PPTC5, and the sixth reset fuse PPTC6 are connected in parallel at their other ends and are jointly connected to the output terminal of the reverse connection protection circuit, the input terminal of the power conversion circuit, the door handle mechanical latch intelligent control module, and the cathode of the dual-color light-emitting diode; the two anodes of the dual-color light-emitting diode are respectively connected to the sources of the second MOS switch Q2 and the third MOS switch Q3; the door handle mechanical latch intelligent control module is also connected to the source of the first MOS switch Q1 and the DSP circuit.

2. The automotive concealed door handle circuit according to claim 1, characterized in that: The fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are polymer positive temperature coefficient type thermal transient resistors.

3. The automotive concealed door handle circuit according to claim 2, characterized in that: The fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are rectangular in shape, with dimensions of 40.0 mm in length, 6.0 mm in width, and 2.0 mm in thickness. The fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 have a withstand voltage greater than 600V, a normal operating current of 30mA, a surge current of up to 150A, and a resistance value in the range of 30Ω to 40Ω.

4. The automotive concealed door handle circuit according to claim 2, characterized in that: The fourth self-resetting fuse PPTC4, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are all covered with a high-voltage thermally conductive insulating film.

5. The automotive concealed door handle circuit according to claim 1, characterized in that: The reverse connection protection circuit includes a first resettable fuse PPTC1, a varistor RV, a bridge rectifier diode, and a filter capacitor C1. The input terminal of the bridge rectifier diode is connected in parallel with the varistor RV, and the output terminal of the bridge rectifier diode is connected in parallel with the filter capacitor C1. One end of the first resettable fuse PPTC1 is connected to the positive terminal of a DC 12V power supply, and the other end of the first resettable fuse PPTC1 is connected to the input terminal of the bridge rectifier diode.

6. The automotive concealed door handle circuit according to claim 1, characterized in that: The power conversion circuit is a DC to DC conversion circuit from 24V to 5.0V and 3.3V.

7. The automotive concealed door handle circuit according to claim 1, characterized in that: The car's invisible door handle circuit also includes a face recognition camera control circuit and a memory circuit. The face recognition camera control circuit is connected to the DSP circuit, and the memory circuit is connected to the MCU.

8. The automotive concealed door handle circuit according to claim 1, characterized in that: The automotive concealed door handle circuit also includes a gate protection circuit, wherein each of the fourth MOS switch Q4, the sixth MOS switch Q6, the first MOS switch Q1, the second MOS switch Q2, and the third MOS switch Q3 is connected in series with the DSP circuit.

9. The automotive concealed door handle circuit according to claim 8, characterized in that: The gate protection circuit of the fourth MOS switch Q4 includes a first resistor R1, a second resistor R2, and a fifth diode D5. The second resistor R2 and the fifth diode D5 are connected in series to form a first branch. The first resistor R1 is connected in parallel across the two ends of the first branch. One end of the first branch is connected to the gate of the fourth MOS switch Q4, and the other end of the first branch is connected to the DSP circuit. The gate protection circuit of the sixth MOS switch Q6 includes a ninth resistor R9, a tenth resistor R10, and a ninth diode D9. The tenth resistor R10 and the ninth diode D9 are connected in series to form a second branch. The ninth resistor R9 is connected in parallel across the two ends of the second branch. One end of the second branch is connected to the gate of the sixth MOS switch Q6, and the other end of the second branch is connected to the DSP circuit. The gate protection circuit of the first MOS switch Q1 includes a seventh resistor R7, an eighth resistor R8, and an eighth diode D8. The eighth resistor R8 and the eighth diode D8 are connected in series to form a third branch. The seventh resistor R7 is connected in parallel across the two ends of the third branch. One end of the third branch is connected to the gate of the first MOS switch Q1, and the other end of the third branch is connected to the DSP circuit. The gate protection circuit of the second MOS switch Q2 includes a third resistor R3, a fourth resistor R4, and a sixth diode D6. The fourth resistor R4 and the sixth diode D6 are connected in series to form a fourth branch. The third resistor R3 is connected in parallel across the two ends of the fourth branch. One end of the fourth branch is connected to the gate of the second MOS switch Q2, and the other end of the fourth branch is connected to the DSP circuit. The gate protection circuit of the third MOS switch Q3 includes a fifth resistor R5, a sixth resistor R6, and a seventh diode D7. The fifth resistor R5 and the seventh diode D7 are connected in series to form a fifth branch. The sixth resistor R6 is connected in parallel across the two ends of the fifth branch. One end of the fifth branch is connected to the gate of the third MOS switch Q3, and the other end of the fifth branch is connected to the DSP circuit.

10. A car, characterized in that: The automotive concealed door handle circuit according to any one of claims 1-9, wherein the fourth self-resetting fuse PPTC4 is embedded in the transverse spacer of the central slot of the H-shaped hard alloy skeleton of the concealed door handle and is fastened by a leaf spring, and the first temperature sensor NTC1, the fifth self-resetting fuse PPTC5, and the sixth self-resetting fuse PPTC6 are installed on the inner wall of the concealed door handle slot.

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