A power supply input protection circuit, a vehicle-mounted wire harness and a vehicle-mounted system

Abstract

This application discloses a power input protection circuit, an automotive wiring harness, and an automotive system, relating to the field of automotive systems. Addressing the problem that current protection circuits directly cut off voltage output upon triggering protection actions, this application provides a power input protection circuit including multiple voltage-limiting protection circuits. Each voltage-limiting protection circuit can reduce the power input voltage to prevent damage to downstream loads when the power input signal exceeds a protection threshold due to voltage fluctuations. This voltage-limiting protection method ensures that the load can still receive power input, thereby guaranteeing the normal operation of the load equipment and not affecting the user experience. Furthermore, multiple voltage-limiting protection circuits correspond to different protection voltage ranges and different target voltage values, ensuring that regardless of the voltage value of the power input signal, there is always a suitable voltage-limiting protection circuit that can effectively limit its voltage, guaranteeing that the power supply voltage output to the load is not excessive and could damage the load equipment.

Description

Technical Field

[0001] This application relates to the field of vehicle systems, and in particular to a power input protection circuit, a vehicle wiring harness, and a vehicle system. Background Technology

[0002] Voltage fluctuations in vehicle systems can directly threaten the reliability and safety of vehicle electronic equipment, and even cause mechanical failures. Common voltage fluctuation problems include overvoltage, undervoltage, surge spikes, and ripple interference, all of which can cause significant damage to vehicle systems. To solve voltage fluctuation problems in vehicle systems, appropriate protection circuits need to be introduced.

[0003] Currently, the core of common voltage fluctuation protection circuits is to quickly cut off the voltage output when the power supply input voltage exceeds a preset voltage threshold, thus preventing damage to downstream loads. However, in practical applications, while cutting off the voltage output can effectively protect the load, it also prevents the load from functioning properly. From the user's perspective, this means that devices in the vehicle system cannot function normally, impacting the user experience.

[0004] Therefore, those skilled in the art urgently need a power input protection circuit to solve the problem that current protection circuits directly cut off the voltage output when triggered, causing the load to fail and affecting the user experience. Summary of the Invention

[0005] The purpose of this application is to provide a power input protection circuit, vehicle wiring harness and vehicle system to solve the problem that the current protection circuit will directly cut off the voltage output when the protection action is triggered, causing the load to fail to work and affecting the user experience.

[0006] To solve the above-mentioned technical problems, this application provides a power supply input protection circuit, including: multiple voltage limiting protection circuits; The input terminals of each voltage limiting protection circuit are interconnected and connected to the input terminal of the power supply input protection circuit for receiving power supply input signals; the output terminals of each voltage limiting protection circuit are interconnected and connected to the output terminal of the power supply input protection circuit for connecting to the load. Each of the voltage limiting protection circuits is used to: when the voltage value of the power supply input signal is within the protection voltage range, limit the voltage value of the power supply input signal to decrease to a target voltage value before outputting; The protection voltage range and target voltage value corresponding to each of the voltage limiting protection circuits are different; according to the upper limit value of the protection voltage range corresponding to each of the voltage limiting protection circuits from low to high, the target voltage value corresponding to each of the voltage limiting protection circuits is from low to high.

[0007] In one optional embodiment, the voltage limiting protection circuit has at least three components; the voltage limiting protection circuit includes: a first-stage protection circuit, an intermediate protection circuit, and a final-stage protection circuit. Wherein, the primary protection circuit is the upper limit value of the target voltage range and the voltage limiting protection circuit with the lowest target voltage value, and the target voltage value corresponding to the primary protection circuit is 0; The final protection circuit is the voltage limiting protection circuit with the highest target voltage value, and the protection voltage range corresponding to the final protection circuit is an infinite interval to the right. The remaining voltage limiting protection circuits are the intermediate protection circuits.

[0008] In one optional embodiment, the intermediate protection circuit includes: a step-down sub-circuit and a comparator switch sub-circuit; The input terminal of the step-down sub-circuit is connected to the input terminal of the corresponding intermediate protection circuit to receive the power supply input signal; the output terminal of the step-down sub-circuit is connected to the input terminal of the comparator switch sub-circuit; and the output terminal of the comparator switch sub-circuit is connected to the output terminal of the corresponding intermediate protection circuit. The step-down sub-circuit is used to: step down the input signal, reduce the voltage value to the target voltage value, and then output the signal. The comparator switch sub-circuit is used to: turn on when the voltage value of the signal connected to the input terminal is less than or equal to the upper limit of the corresponding protection voltage range, and turn off otherwise.

[0009] In one optional embodiment, the primary protection circuit includes: the comparison switch sub-circuit; The input terminal of the comparison switch sub-circuit is connected to the input terminal of the primary protection circuit, and the output terminal of the comparison switch sub-circuit is connected to the output terminal of the primary protection circuit. The final-stage protection circuit includes: the step-down sub-circuit; The input terminal of the step-down sub-circuit is connected to the input terminal of the final stage protection circuit, and the output terminal of the step-down sub-circuit is connected to the output terminal of the final stage protection circuit.

[0010] In one optional embodiment, the step-down sub-circuit includes: a step-down diode, or a plurality of step-down diodes connected end to end in sequence; The number of buck diodes in the buck sub-circuit is positively correlated with the target voltage value corresponding to the buck sub-circuit.

[0011] In one optional embodiment, the comparator switch sub-circuit includes: a Zener diode, a first transistor, a first MOSFET, a first resistor, a second resistor, and a third resistor; Wherein, the first end of the first resistor serves as the input terminal of the comparator switch sub-circuit and is connected to the emitter of the first transistor and the source of the first MOSFET; the second end of the first resistor is connected to the negative terminal of the Zener diode and the second end of the second resistor; the positive terminal of the Zener diode is grounded; the first end of the second resistor is connected to the base of the first transistor; the gate of the first MOSFET is connected to the collector of the first transistor and is grounded through the third resistor; the drain of the first MOSFET serves as the output terminal of the comparator switch sub-circuit.

[0012] In one optional embodiment, it further includes: a voltage regulator and current limiting circuit; The voltage stabilizing and current limiting circuit is disposed between the output terminal of each of the voltage limiting protection circuits and the output terminal of the power supply input protection circuit, and is used to: stabilize the output voltage of the power supply input protection circuit and limit the output current of the power supply input protection circuit.

[0013] In one optional embodiment, the voltage regulator and current limiting circuit includes: a fourth resistor, a current mirror, a first amplifier circuit, and a second amplifier circuit; The first end of the fourth resistor serves as the input terminal of the voltage regulator and current limiter circuit; The current mirror source includes: a second MOSFET, a third MOSFET, a fourth MOSFET, and a fifth resistor; wherein, the drain of the second MOSFET is connected to the second terminal of the fourth resistor and the drain of the third MOSFET; the gate of the second MOSFET is connected to the drain of the fourth MOSFET; the source of the second MOSFET serves as the output terminal of the voltage regulator and current limiter circuit; the sources of the third MOSFET and the fourth MOSFET are interconnected and grounded through the fifth resistor; The first amplifier circuit includes: a first amplifier, a sixth resistor, a seventh resistor, and an eighth resistor; wherein, the non-inverting input terminal of the first amplifier is connected to the first terminal of the fourth resistor through the sixth resistor; the inverting input terminal of the first amplifier is connected to the second terminal of the fourth resistor through the seventh resistor; the inverting input terminal of the first amplifier is also connected to the output terminal of the first amplifier through the eighth resistor; and the output terminal of the first amplifier is connected to the gate of the third MOS transistor. The second amplifier circuit includes: a second amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor; wherein, the output terminal of the second amplifier is connected to the gate of the fourth MOS transistor; the output terminal of the second amplifier is also connected to the inverting input terminal of the second amplifier through the ninth resistor; the inverting input terminal of the second amplifier is also connected to the first terminal of the tenth resistor; the second terminal of the tenth resistor is grounded through the eleventh resistor; the second terminal of the tenth resistor is also connected to the source of the second MOS transistor through the twelfth resistor; the non-inverting input terminal of the second amplifier is grounded through the thirteenth resistor; and the non-inverting input terminal of the second amplifier is also connected to the source of the second MOS transistor through the fourteenth resistor.

[0014] To address the aforementioned technical problems, this application also provides an on-board wiring harness, including the power input protection circuit described above.

[0015] To address the aforementioned technical problems, this application also provides an in-vehicle system, including the power input protection circuit described above; or, including the in-vehicle wiring harness described above.

[0016] This application provides a power input protection circuit, including multiple voltage limiting protection circuits. Each voltage limiting protection circuit limits the voltage value of the power input signal to a target voltage value before outputting it when the voltage value is within the protection voltage range. In other words, the voltage limiting protection circuit can prevent damage to downstream loads by reducing the power input voltage when the voltage value exceeds the protection threshold due to voltage fluctuations. This voltage limiting protection method ensures that the load can still receive power input, thus guaranteeing the normal operation of the load equipment and not affecting the user experience. Furthermore, this circuit includes multiple voltage limiting protection circuits, each corresponding to a different protection voltage range and a different target voltage value. The higher the upper limit of the corresponding protection voltage range, the higher the target voltage value, meaning a greater limiting effect on the power input voltage. Based on this setting, it ensures that no matter how high the voltage value of the power input signal is, there is always a suitable voltage limiting protection circuit that can effectively limit its voltage, ensuring that the power supply voltage output to the load is not too high and could damage the load equipment.

[0017] The vehicle wiring harness and vehicle system provided in this application correspond to the aforementioned power input protection circuit and have the same effect. Attached Figure Description

[0018] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only 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 structural diagram of a power input protection circuit provided in an embodiment of the present invention; Figure 2 A structural diagram of a three-level voltage limiting protection circuit provided in an embodiment of the present invention; Figure 3 A circuit schematic diagram of a primary protection circuit provided in an embodiment of the present invention; Figure 4 A circuit diagram of an intermediate protection circuit provided in an embodiment of the present invention; Figure 5 A circuit diagram of a final-stage protection circuit provided in an embodiment of the present invention; Figure 6 A circuit diagram of a three-level voltage limiting protection circuit provided in an embodiment of the present invention; Figure 7 A structural diagram of another power supply input protection circuit provided in an embodiment of the present invention; Figure 8 The circuit diagram is provided for an embodiment of the present invention.

[0020] Among them, 1-voltage limiting protection circuit, 11-first stage protection circuit, 12-intermediate protection circuit, 13-final stage protection circuit; 2-voltage regulation and current limiting circuit, 21-mirror current source, 22-first amplifier circuit, 23-second amplifier circuit. Detailed Implementation

[0021] 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. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0022] The core of this application is to provide a power input protection circuit, an automotive wiring harness, and an automotive system.

[0023] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Currently, the mainstream overvoltage protection solution is to quickly cut off the voltage output when the input voltage exceeds a preset voltage threshold to prevent damage to downstream loads. However, cutting off the voltage output also means that downstream loads have no power input and cannot function properly. In practical applications, users will perceive that some devices (loads) in the vehicle system suddenly lose power and cannot function properly, affecting the user experience.

[0025] To address the aforementioned problems, this application provides a power supply input protection circuit, such as... Figure 1 As shown, the system includes multiple voltage limiting protection circuits 1. The input terminals of each voltage limiting protection circuit 1 are interconnected and connected to the input terminal of a power supply input protection circuit for receiving power supply input signals. The output terminals of each voltage limiting protection circuit 1 are interconnected and connected to the output terminal of the power supply input protection circuit for connection to a load. Each voltage limiting protection circuit 1 is used to: when the voltage value of the power supply input signal is within the protection voltage range, limit the voltage value of the power supply input signal to decrease to a target voltage value before outputting. The protection voltage range and target voltage value corresponding to each voltage limiting protection circuit 1 are different. Based on the upper limit of the protection voltage range corresponding to each voltage limiting protection circuit 1 from low to high, the target voltage value corresponding to each voltage limiting protection circuit 1 is from low to high.

[0026] It should be noted that, Figure 1 The example shown is only one possible scenario where there are three voltage limiting protection circuits 1. This embodiment does not limit the number of voltage limiting protection circuits 1 to three; it can be two or more.

[0027] Furthermore, regarding the protection voltage range corresponding to each voltage limiting protection circuit 1, although this embodiment does not limit the specific values ​​of the protection voltage range, to maximize the use of limited resources, the protection voltage ranges corresponding to each voltage limiting protection circuit 1 should not overlap. Moreover, to ensure effective suppression of voltage fluctuations in the power supply input signal, the set of protection voltage ranges for all voltage limiting protection circuits 1 should cover the possible voltage range of the power supply input signal. For example... Figure 1 As shown, the voltage range of the power supply input signal is 4.5V~7.8V. Therefore, the protection voltage ranges of the three voltage limiting protection circuits 1 are 4.5V~6V, 6V~7V, and 7V~7.8V, respectively. This ensures that they do not overlap with each other and that they can completely cover the possible voltage range of the power supply input.

[0028] Furthermore, this embodiment does not restrict the specific value of the target voltage corresponding to each voltage limiting protection circuit 1, but only sets certain requirements on the magnitude relationship between them. It should be noted that the target voltage value is the parameter guide for the voltage limiting protection circuit 1 to perform voltage reduction. After a power supply input signal falling within the corresponding protection voltage range is connected to the voltage limiting protection circuit 1, the voltage limiting protection circuit 1 should output a power supply input signal with a voltage value reduced by the target voltage value. The target voltage value can be equal to 0, but it should at least not be less than 0; otherwise, it is equivalent to voltage boosting and cannot achieve the purpose of suppressing overvoltage fluctuations. When the target voltage value is equal to 0, it is equivalent to this voltage limiting protection circuit 1 not performing voltage reduction processing on the power supply input signal. The scenario where the target voltage is equal to 0 is suitable when the voltage value of the power supply input signal meets the stability requirements, that is, in this case, there is no need to limit the voltage of the power supply input signal.

[0029] Next, we will discuss the specific implementation of the voltage limiting protection circuit 1. As mentioned above, the main functions of the voltage limiting protection circuit 1 involve: determining whether the voltage value of the power supply input signal is within the protection voltage range (voltage comparison) and limiting the voltage value of the power supply input signal to decrease to the target voltage value (voltage reduction). Therefore, the voltage limiting protection circuit 1 can be implemented using devices or circuits with voltage comparison and voltage reduction functions, such as voltage comparators, voltage reduction circuits, etc.

[0030] Furthermore, since the input terminals of each voltage limiting protection circuit 1 are interconnected and share the same power supply input signal, and since the protection voltage ranges of each voltage limiting protection circuit 1 are different (and do not overlap), in one optional embodiment, only one voltage limiting protection circuit 1 performs its corresponding function at any given time, that is, it steps down the input power supply signal before outputting it. Thus, to prevent the output of other voltage limiting protection circuits 1 from affecting the downstream load, an optional solution is to disable the output of other voltage limiting protection circuits 1. That is, only one voltage limiting protection circuit 1 has an output at any given time. This function can be implemented using a switching device. A switching device, such as a transistor, MOSFET, or other switch, is set in the output path of the voltage limiting protection circuit 1. When the voltage value of the input power supply signal falls within the corresponding protection voltage range, this switching device is turned on; otherwise, it is turned off. This switching control logic can be implemented using the signal output from a device (such as a voltage comparator) that performs voltage comparison in the voltage limiting protection circuit 1, which is then output as a control signal to the controlled terminal of the switching device.

[0031] As described above, the power supply input protection circuit provided in this application achieves overvoltage protection by limiting (reducing) the voltage of the power supply input signal. Multiple voltage limiting protection circuits 1 are adapted to different protection voltage ranges, corresponding to overvoltage problems of varying severity. Voltage limiting is achieved through different levels of voltage reduction (i.e., different target voltage values), thus suppressing fluctuations in the power supply input voltage. Simultaneously, because this circuit limits the voltage output rather than cutting off the voltage output, the downstream load still has a power supply input and can operate normally. On the user side, the user is unaware of voltage fluctuations in the power supply input signal and the overvoltage protection process, and the user experience is not affected.

[0032] Furthermore, the above embodiments do not limit the number of voltage limiting protection circuits 1; there can be two, three, or even more. This embodiment provides a further implementation scheme for the possibility that the number of voltage limiting protection circuits 1 is at least three. For example... Figure 2 As shown, the aforementioned voltage limiting protection circuit 1 includes: a primary protection circuit 11, intermediate protection circuits 12, and a final protection circuit 13. The primary protection circuit 11 corresponds to the upper limit of the target voltage range and is the voltage limiting protection circuit 1 with the lowest target voltage value, and the target voltage value corresponding to the primary protection circuit 11 is 0. The final protection circuit 13 corresponds to the voltage limiting protection circuit 1 with the highest target voltage value, and the protection voltage range corresponding to the final protection circuit 13 is an infinite interval. The remaining voltage limiting protection circuits 1 are intermediate protection circuits 12.

[0033] As mentioned in the above embodiments, different voltage limiting protection circuits 1 correspond to different protection levels (i.e., different protection voltage ranges and target voltage values). In this embodiment, the two voltage limiting protection circuits 1 with the lowest and highest protection levels are referred to as the first-stage protection circuit 11 and the last-stage protection circuit 13, respectively, while the remaining voltage limiting protection circuits 1 with neither the lowest nor the highest protection levels are referred to as intermediate protection circuits 12.

[0034] For the primary protection circuit 11, its corresponding protection level is the lowest, that is, its corresponding protection voltage range and target voltage value are the lowest. As can be seen from the above embodiments, to cover all operating conditions of the power supply input signal, this circuit should be usable when the power supply input signal is not overvoltaged. In this case, the power supply input signal should not be restricted. This is achieved in this embodiment through the primary protection circuit 11. Therefore, the target voltage value of the collection protection circuit in this embodiment is 0.

[0035] Furthermore, the final-stage protection circuit 13 has the highest protection level, meaning it has the highest protection voltage range and target voltage value. It's easy to see that, due to variations in requirements and scenarios in practical applications, the maximum voltage of the power supply input signal theoretically has no upper limit. That is, the highest-level voltage-limiting protection circuit 1 might provide overvoltage protection in the current scenario, but fail to do so in other scenarios because the voltage of the power supply input signal exceeds the upper limit of its protection voltage range. To address this, this embodiment sets the protection voltage range of the highest-level final-stage protection circuit 13 to a right-infinite range, meaning it has only a specific lower limit and an infinite upper limit. This provides a basic overvoltage protection function for all possible power supply input voltage conditions.

[0036] Meanwhile, based on the aforementioned functional changes to the primary protection circuit 11 and the secondary protection circuit 13, the primary protection circuit 11 no longer needs to perform voltage reduction, and the secondary protection circuit 13 no longer needs to compare the power supply input signal voltage value with the upper limit of the protection voltage range. This reduction in functionality also allows for a corresponding reduction in the requirements for the circuit structure. For example, the voltage reduction section is no longer needed in the primary protection circuit 11, and the voltage comparison section in the secondary protection circuit 13 can omit the comparison between the power supply input signal voltage value and the upper limit of the protection voltage range, further simplifying the circuit structure.

[0037] Specifically, this embodiment also provides a general structure for an optional voltage limiting protection circuit 1. That is, the specific structure of the aforementioned intermediate protection circuit 12, where the first-stage protection circuit 11 and the final-stage protection circuit 13 can be simplified based on this circuit structure. The intermediate protection circuit 12 provided in this embodiment includes: a step-down sub-circuit and a comparator switch sub-circuit. The input terminal of the step-down sub-circuit is connected to the input terminal of the corresponding intermediate protection circuit 12, used to receive the power supply input signal; the output terminal of the step-down sub-circuit is connected to the input terminal of the comparator switch sub-circuit; the output terminal of the comparator switch sub-circuit is connected to the output terminal of the corresponding intermediate protection circuit 12. The step-down sub-circuit is used to: step down the input signal, reducing the voltage value to the corresponding target voltage value before outputting. The comparator switch sub-circuit is used to: turn on when the voltage value of the input signal is less than or equal to the upper limit of the corresponding protection voltage range, otherwise turn off.

[0038] As described above, the two core functions of the voltage limiting protection circuit 1 are voltage comparison and voltage limiting, as well as the further extended switching control function in the above embodiment (this circuit is turned off when the voltage value of the power supply input signal is not within the corresponding protection voltage range). This embodiment achieves this through two sub-circuits: a comparison switching sub-circuit and a step-down sub-circuit.

[0039] The comparator switch sub-circuit is mainly used to implement the voltage comparison and switching control functions described above. However, it should be noted that the comparator switch sub-circuit in this embodiment only needs to compare the voltage value of the power supply input signal with the upper limit of the protection voltage range. In this case, although multiple voltage limiting protection circuits 1 may be active simultaneously (i.e., the voltage value of the power supply input signal is simultaneously less than the upper limit of the protection voltage range corresponding to multiple voltage limiting protection circuits 1), because the voltage reduction measure of the buck sub-circuit limits the power supply input signal, the voltage drop (target voltage value) of different voltage limiting protection circuits 1 is different. Therefore, the power supply input signal will preferentially pass through the branch with the lower voltage drop, that is, preferentially pass through the voltage limiting protection circuit 1 with the lowest target voltage value, avoiding excessive restriction. Based on this, the comparator switch sub-circuit in this embodiment only needs to compare the voltage value of the power supply input signal with the upper limit of the protection voltage range to achieve the above voltage comparison and switching control functions, further simplifying the circuit structure.

[0040] Furthermore, as described in the above embodiments regarding the final-stage protection circuit 13, the protection voltage range of the final-stage protection circuit 13 is an infinitely large range, meaning the upper limit is infinitely large. In this case, it is impossible to compare the upper limit with the power supply input signal voltage value; that is, the final-stage protection circuit 13 does not need a comparison switch sub-circuit and can remain always on. Since the target voltage value of the final-stage protection circuit 13 is the highest, i.e., the voltage drop is the largest, when other voltage-limiting protection circuits 1 besides the final-stage protection circuit 13 are on, the power supply input signal is preferentially output from these other voltage-limiting protection circuits 1. When no other voltage-limiting protection circuits 1 besides the final-stage protection circuit 13 are on, it indicates that the voltage value of the power supply input signal is too large, and it needs to be and can only be passed through the final-stage protection circuit 13 to achieve voltage limitation and suppress overvoltage.

[0041] That is, this embodiment also provides an optional solution for the final-stage protection circuit 13, which includes a step-down sub-circuit. The input terminal of the step-down sub-circuit is connected to the input terminal of the final-stage protection circuit 13, and the output terminal of the step-down sub-circuit is connected to the output terminal of the final-stage protection circuit 13. Therefore, the final-stage protection circuit 13 provided in this embodiment is simple and reliable to implement, and can be achieved using only a step-down sub-circuit with a step-down function.

[0042] Furthermore, the main function of the buck converter sub-circuit is to step down the voltage of the input signal. This can be achieved using devices or circuits such as diodes and buck converters; this embodiment does not impose any limitations on this. The voltage drop of the buck converter sub-circuit is determined based on the corresponding target voltage value. For example... Figure 2 As shown, the target voltage values ​​corresponding to the primary protection circuit 11, intermediate protection circuit 12 and final protection circuit 13 are 0V, 1V and 2V respectively, and their corresponding voltage drops are 0V, 1V and 2V respectively.

[0043] In this embodiment, a voltage drop of 0V can be considered as not requiring a step-down circuit, meaning no step-down sub-circuit is needed. Therefore, this embodiment also provides a suitable alternative solution for the aforementioned primary protection circuit 11. The aforementioned primary protection circuit 11 includes a comparator switch sub-circuit. The input terminal of the comparator switch sub-circuit is connected to the input terminal of the primary protection circuit 11, and the output terminal of the comparator switch sub-circuit is connected to the output terminal of the primary protection circuit 11. Thus, the primary protection circuit 11 structure provided in this embodiment can be achieved simply by removing the step-down sub-circuit portion from the intermediate protection circuit 12 structure (i.e., the general voltage limiting protection circuit 1 structure) provided in the aforementioned embodiment. The overall circuit structure is simple, reliable, and easy to implement.

[0044] Furthermore, regarding the specific structures of the aforementioned step-down sub-circuit and comparator switch sub-circuit, this embodiment also provides a suitable alternative solution. For example... Figure 4 and Figure 5 As shown, the aforementioned step-down sub-circuit includes: a step-down diode (such as...) Figure 4 (e.g., diode D1), or multiple step-down diodes connected end-to-end (e.g., ...) Figure 5 The diodes D1, D2, and D3 are connected in sequence, among which... Figure 5 Diode D1 in Figure 4 The diode D1 mentioned is the same diode, which will be discussed later. Figure 4 , Figure 5 (The specific circuit structure will be further explained in the embodiments). The number of buck diodes in the buck sub-circuit is positively correlated with the target voltage value corresponding to the buck sub-circuit.

[0045] In addition, such as Figure 3 and Figure 4 As shown, the aforementioned comparator switch sub-circuit includes: a Zener diode (such as...) Figure 3 Zener diode Z1, or Figure 4 Zener diode Z2), first transistor (such as...) Figure 3 Transistor T1 in the middle, or Figure 4 Transistor T3), the first MOSFET (such as...) Figure 3 MOSFET T2 in the middle, or Figure 4 In the MOSFET T4), the first resistor (such as Figure 3 The resistor R1 in the middle, or Figure 4 The resistor R4 in the middle), the second resistor (such as Figure 3 The resistor R2 in the middle, or Figure 4 The resistor R5 in the middle) and the third resistor (such as Figure 3 The resistor R3 in the middle, or Figure 4 (R6 in the middle).

[0046] Among them, due to Figure 3 and Figure 4 The structure of the comparator switch sub-circuit is exactly the same as that of the circuit in the following example. Figure 3 To illustrate the connection relationship between the components in the comparison switch sub-circuit, the first end of the first resistor R2 serves as the input terminal of the comparison switch sub-circuit, connected to the emitter of the first transistor T1 and the source of the first MOSFET T2; the second end of the first resistor R1 is connected to the negative terminal of the Zener diode Z1 and the second end of the second resistor R2; the positive terminal of the Zener diode Z1 is grounded; the first end of the second resistor R2 is connected to the base of the first transistor T1; the gate of the first MOSFET T2 is connected to the collector of the first transistor T1 and grounded through the third resistor R3; the drain of the first MOSFET T2 serves as the output terminal of the comparison switch sub-circuit.

[0047] Based on the specific implementation schemes of the step-down sub-circuit and the comparator switch sub-circuit provided in the two embodiments above, the circuit structure of the first-stage protection circuit 11 is as follows: Figure 3 As shown, the circuit structure of the intermediate protection circuit 12 described above is as follows: Figure 4 As shown, the circuit structure of the aforementioned final-stage protection circuit 13 is as follows: Figure 5 As shown. Furthermore, the circuit structure of the power supply input protection circuit, consisting of three voltage-limiting protection circuits 1 (i.e., a primary protection circuit 11, an intermediate protection circuit 12, and a final protection circuit 13), is as follows: Figure 6 As shown. Figures 3-6 They share the same set of circuit markings, where Vin represents the power supply input signal (voltage); Vout represents the output (voltage) of the power supply input protection circuit; VF1~VF7 represent 7 test ports, used for simulation testing, which can be omitted in actual implementation.

[0048] Furthermore, in combination Figure 2 The given parameter example assumes that the voltage range of the power supply input signal Vin is 4.5V~7.8V, the protection voltage range of the first-stage protection circuit 11 is 4.5V~6V, the protection voltage range of the intermediate protection circuit 12 is 6V~7V, and the protection voltage range of the final-stage protection circuit 13 is 7V~7.8V.

[0049] 1. Vin≤6V; Since the power supply input voltage Vin is less than 6V, it falls within the target voltage range of the primary protection circuit 11. At this time, if... Figure 3 As shown, the work path can be further divided into two cases: Firstly, Zener diode Z1 outputs current limited by resistor R1. When the voltage across Zener diode Z1 does not exceed 5.1V, Z1 is turned off. At this time, the base voltage of transistor T1 (PNP type) equals the emitter voltage, which equals the supply input voltage Vin, resulting in a base-emitter voltage Vbe = 0V. Since transistor T1 is turned off, the gate-source voltage Vgs of MOSFET T2 (P type) is less than -2V. MOSFET T2 then turns on, and the supply input signal is output through MOSFET T2, with a voltage range of 5V to 6V.

[0050] Secondly, when the voltage across Zener diode Z1 exceeds 5.1V, Z1 turns on, and the voltage across Z1 stabilizes at 5.1V. At this time, a stable 5.1V voltage is provided to the base of transistor TI through resistor R3, but the voltage at the emitter of transistor TI is equal to the supply input voltage Vin. As the supply input voltage Vin increases, when Vbe of transistor T1 is less than -0.7V, transistor TI turns on, and the source of MOSFET T2 is pulled low to ground, resulting in Vgs = 0V. At this time, MOSFET T2 turns off, which means the first-stage protection circuit 11 is off, and there is no output.

[0051] 2.6V <Vin≤7V; At this time, the power supply input voltage Vin is within the target voltage range of the intermediate protection circuit 12, and the MOSFET T2 in the primary protection circuit 11 is turned off. Figure 4 As shown, the power supply input voltage Vin, after being stepped down by diode D1 (assuming the voltage drop is 0.7V), enters the voltage range... Figure 3 In a completely identical comparison switch sub-circuit, its operating path can also be divided into two cases: Firstly, Zener diode Z2 outputs current limited by resistor R4. When the voltage across Zener diode Z2 does not exceed 5.6V, Z2 is turned off. At this time, the base voltage of transistor T3 (PNP type) equals the emitter voltage, which equals the supply input voltage Vin, resulting in a base-emitter voltage Vbe = 0V. Since transistor T3 is turned off, the gate-source voltage Vgs of MOSFET T4 (P type) is less than -2V. MOSFET T4 is then turned on, and the supply input signal is output through MOSFET T4, with a voltage range of 5V to 6V.

[0052] Secondly, when the voltage across Zener diode Z1 exceeds 5.6V, Zener diode Z2 turns on, and the voltage across Zener diode Z2 stabilizes at 5.6V. At this time, a stable 5.6V voltage is provided to the base of transistor T3 through resistor R6, but the voltage at the emitter of transistor T3 is equal to the supply input voltage Vin. As the supply input voltage Vin increases, when Vbe of transistor T3 is less than -0.7V, transistor T3 turns on, and the source of MOSFET T4 is pulled low to ground, resulting in Vgs = 0V. At this time, MOSFET T4 turns off, that is, the intermediate protection circuit 12 is turned off, and there is no output.

[0053] 3.7V <Vin≤7.8V; At this time, the power supply input voltage Vin is within the target voltage range of the final protection circuit 13. Therefore, MOSFET T2 in the first-stage protection circuit 11 is turned off, and MOSFET T4 in the intermediate protection circuit 12 is also turned off. For example... Figure 5 As shown, the power supply input voltage Vin is stepped down through three diodes D1~D3 connected in a single step, so that the output voltage range is stabilized within 5V~6V.

[0054] In summary, this embodiment provides a simple, reliable, and already implemented solution for the specific structure of the voltage limiting protection circuit 1. The function of the voltage limiting protection circuit 1 can be achieved using only a switching transistor, a Zener diode, and a resistor. It effectively limits the output of power supply input signals with different voltages, ensuring that the downstream load receives a voltage supply within a stable range.

[0055] Furthermore, this embodiment also provides another optional embodiment, such as... Figure 7 As shown, the circuit also includes a voltage regulator and current limiter circuit 2. The voltage regulator and current limiter circuit 2 is disposed between the output terminal of each voltage limiting protection circuit 1 and the output terminal of the power supply input protection circuit, and is used to stabilize the output voltage of the power supply input protection circuit and limit the output current of the power supply input protection circuit.

[0056] As can be seen from the above, the core functions of the voltage regulator and current limiting circuit 2 provided in this embodiment are voltage regulation and current limiting. Therefore, the voltage regulator and current limiting circuit 2 in this embodiment can be implemented by a voltage regulator circuit and a current limiting circuit. In addition, this embodiment also provides another implementation scheme for the voltage regulator and current limiting circuit 2, such as... Figure 8 As shown, the voltage regulator and current limiting circuit 2 mentioned above includes: a fourth resistor R8, a current mirror 21, a first amplifier circuit 22, and a second amplifier circuit 23.

[0057] The first terminal of the fourth resistor R8 serves as the input terminal of the voltage regulator and current limiting circuit 2. The mirror current source 21 includes: a second MOSFET T5, a third MOSFET T6, a fourth MOSFET T7, and a fifth resistor R9; wherein, the drain of the second MOSFET T5 is connected to the second terminal of the fourth resistor R8 and the drain of the third MOSFET T6; the gate of the second MOSFET T5 is connected to the drain of the fourth MOSFET T7; the source of the second MOSFET T5 serves as the output terminal of the voltage regulator and current limiting circuit 2; the sources of the third MOSFET T6 and the fourth MOSFET T7 are interconnected and grounded through the fifth resistor R9.

[0058] The first amplifier circuit 22 includes: a first amplifier U1, a sixth resistor R10, a seventh resistor R11, and an eighth resistor R12; wherein, the non-inverting input terminal of the first amplifier U1 is connected to the first terminal of the fourth resistor R8 through the sixth resistor R10; the inverting input terminal of the first amplifier U1 is connected to the second terminal of the fourth resistor R8 through the seventh resistor R11; the inverting input terminal of the first amplifier U1 is also connected to the output terminal of the first amplifier U1 through the eighth resistor R12; the output terminal of the first amplifier U1 is connected to the gate of the third MOSFET T6.

[0059] The second amplifier circuit 23 includes: a second amplifier U2, a ninth resistor R13, a tenth resistor R14, an eleventh resistor R15, a twelfth resistor R16, a thirteenth resistor R17, and a fourteenth resistor R18; wherein, the output terminal of the second amplifier U2 is connected to the gate of the fourth MOSFET T7; the output terminal of the second amplifier U2 is also connected to the inverting input terminal of the second amplifier U2 through the ninth resistor R13; the inverting input terminal of the second amplifier U2 is also connected to the first terminal of the tenth resistor R14; the second terminal of the tenth resistor R14 is grounded through the eleventh resistor R15; the second terminal of the tenth resistor R14 is also connected to the source of the second MOSFET T5 through the twelfth resistor R16; the non-inverting input terminal of the second amplifier U2 is grounded through the thirteenth resistor R17; and the non-inverting input terminal of the second amplifier U2 is also connected to the source of the second MOSFET T5 through the fourteenth resistor R18.

[0060] like Figure 8 As shown, the voltage regulator and current limiting circuit 2 provided in this embodiment mainly consists of two parts: First, a current mirror source is formed by the second MOSFET T5, the third MOSFET T6, the fourth MOSFET T7, and the fifth resistor R9. In this part, the third MOSFET T6 and the fourth MOSFET T7 operate in the amplification region. By adjusting the voltage divider ratio of the twelfth resistor R16 / thirteenth resistor R17, the reference voltage at the inverting input ("-") terminal of the second amplifier U2 can be adjusted. By proportionally controlling the ninth resistor R13, the tenth resistor R14, the thirteenth resistor R17, and the fourteenth resistor R18, the voltages at the non-inverting input ("+") terminal and the inverting input terminal of the second amplifier U2 can be adjusted. This adjusts the amplification factor of the second amplifier U2, thereby controlling its output and consequently controlling the gate voltage of the fourth MOSFET T7. By controlling the gate voltage of the fourth MOSFET T7, the gate voltage of the second MOSFET T5 can be controlled, ensuring a stable output voltage for this circuit.

[0061] Secondly, the fourth resistor R8 is a current-limiting detection resistor. The load current passing through the fourth resistor R8 will generate a voltage difference. The first amplifier U1 provides a reference voltage to the "+" and "-" terminals through the sixth resistor R10 and the seventh resistor R11. The amplification factor of the first amplifier U1 can be controlled by adjusting the ratio of the eighth resistor R12 and the seventh resistor R11. The amplified output of the first amplifier U1 amplifies the voltage across the fourth resistor R8 and outputs it to the gate of the third MOSFET T6. Changes in the gate voltage of the third MOSFET T6 affect the gate voltage of the second MOSFET T5, thereby controlling the output of the second MOSFET T5 and achieving the purpose of controlling the output of the entire circuit.

[0062] As described above, this embodiment provides a specific implementation scheme for a voltage-stabilizing and current-limiting circuit 2, which can achieve both voltage stabilization and current limiting functions with a single circuit. It can further modulate the power supply input signal to ensure stable power supply to the load, thereby improving the safety and reliability of load operation.

[0063] In the above embodiments, a power input protection circuit has been described in detail. This application also provides an embodiment corresponding to an automotive wiring harness. Specifically, this embodiment provides an automotive wiring harness including the power input protection circuit provided in any of the above embodiments.

[0064] In addition, this embodiment also provides an embodiment corresponding to an in-vehicle system. The in-vehicle system provided in this embodiment includes the power input protection circuit provided in any of the above embodiments, or includes the in-vehicle wiring harness provided in the above embodiments.

[0065] Since the embodiments of the vehicle wiring harness and vehicle system part correspond to the embodiments of the power supply input protection circuit part, please refer to the description of the embodiments of the power supply input protection circuit part for the embodiments of the vehicle wiring harness and vehicle system part, and will not be repeated here.

[0066] The vehicle wiring harness and vehicle system provided in the above embodiments of this application, by including the power input protection circuit provided in the above embodiments, can achieve the technical effects achieved by the power input protection circuit. Specifically, overvoltage protection can be achieved by limiting the voltage of the power input signal. Multiple voltage limiting protection circuits are adapted to different protection voltage ranges, that is, corresponding to overvoltage problems of varying severity, and voltage limiting is achieved through different levels of voltage reduction processing, thereby suppressing power input voltage fluctuations. Simultaneously, because this vehicle wiring harness / vehicle system limits voltage output rather than cutting off voltage output, downstream loads still have power input and can operate normally. On the user side, the user is unaware of voltage fluctuations in the power input signal and the overvoltage protection process, and the user experience is not affected.

[0067] The above provides a detailed description of a power input protection circuit, vehicle wiring harness, and vehicle system provided in this application. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

[0068] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A power supply input protection circuit, characterized in that, include: Multiple voltage limiting protection circuits; The input terminals of each voltage limiting protection circuit are interconnected and connected to the input terminal of the power supply input protection circuit for receiving power supply input signals; The output terminals of each of the voltage limiting protection circuits are interconnected and connected to the output terminal of the power supply input protection circuit to connect to the load; Each of the voltage limiting protection circuits is used to: when the voltage value of the power supply input signal is within the protection voltage range, limit the voltage value of the power supply input signal to decrease to a target voltage value before outputting; The protection voltage range and the target voltage value are different for each of the voltage limiting protection circuits. According to the order of the upper limit value of the protection voltage range corresponding to each voltage limiting protection circuit from low to high, the target voltage value corresponding to each voltage limiting protection circuit is from low to high.

2. The power input protection circuit according to claim 1, characterized in that, The voltage limiting protection circuit has at least three components; the voltage limiting protection circuit includes: a first-stage protection circuit, an intermediate protection circuit, and a final-stage protection circuit. Wherein, the primary protection circuit is the upper limit value of the target voltage range and the voltage limiting protection circuit with the lowest target voltage value, and the target voltage value corresponding to the primary protection circuit is 0; The final protection circuit is the voltage limiting protection circuit with the highest target voltage value, and the protection voltage range corresponding to the final protection circuit is an infinite interval to the right. The remaining voltage limiting protection circuits are the intermediate protection circuits.

3. The power supply input protection circuit according to claim 2, characterized in that, The intermediate protection circuit includes: a step-down sub-circuit and a comparator switch sub-circuit; The input terminal of the step-down sub-circuit is connected to the input terminal of the corresponding intermediate protection circuit to receive the power supply input signal; the output terminal of the step-down sub-circuit is connected to the input terminal of the comparator switch sub-circuit; and the output terminal of the comparator switch sub-circuit is connected to the output terminal of the corresponding intermediate protection circuit. The step-down sub-circuit is used to: step down the input signal, reduce the voltage value to the target voltage value, and then output the signal. The comparator switch sub-circuit is used to: turn on when the voltage value of the signal connected to the input terminal is less than or equal to the upper limit of the corresponding protection voltage range, and turn off otherwise.

4. The power input protection circuit according to claim 3, characterized in that, The primary protection circuit includes: the comparison switch sub-circuit; The input terminal of the comparison switch sub-circuit is connected to the input terminal of the primary protection circuit, and the output terminal of the comparison switch sub-circuit is connected to the output terminal of the primary protection circuit. The final-stage protection circuit includes: the step-down sub-circuit; The input terminal of the step-down sub-circuit is connected to the input terminal of the final stage protection circuit, and the output terminal of the step-down sub-circuit is connected to the output terminal of the final stage protection circuit.

5. The power input protection circuit according to claim 4, characterized in that, The step-down sub-circuit includes: a step-down diode, or multiple step-down diodes connected end to end in sequence; The number of buck diodes in the buck sub-circuit is positively correlated with the target voltage value corresponding to the buck sub-circuit.

6. The power supply input protection circuit according to claim 4, characterized in that, The comparator switch sub-circuit includes: a Zener diode, a first transistor, a first MOSFET, a first resistor, a second resistor, and a third resistor; Wherein, the first end of the first resistor serves as the input terminal of the comparator switch sub-circuit and is connected to the emitter of the first transistor and the source of the first MOSFET; the second end of the first resistor is connected to the negative terminal of the Zener diode and the second end of the second resistor; the positive terminal of the Zener diode is grounded; the first end of the second resistor is connected to the base of the first transistor; the gate of the first MOSFET is connected to the collector of the first transistor and is grounded through the third resistor; the drain of the first MOSFET serves as the output terminal of the comparator switch sub-circuit.

7. The power supply input protection circuit according to any one of claims 1 to 6, characterized in that, Also includes: Voltage regulation and current limiting circuit; The voltage stabilizing and current limiting circuit is disposed between the output terminal of each of the voltage limiting protection circuits and the output terminal of the power supply input protection circuit, and is used to: stabilize the output voltage of the power supply input protection circuit and limit the output current of the power supply input protection circuit.

8. The power input protection circuit according to claim 7, characterized in that, The voltage regulator and current limiting circuit includes: a fourth resistor, a current mirror source, a first amplifier circuit, and a second amplifier circuit. The first end of the fourth resistor serves as the input terminal of the voltage regulator and current limiter circuit; The current mirror source includes: a second MOSFET, a third MOSFET, a fourth MOSFET, and a fifth resistor; wherein, the drain of the second MOSFET is connected to the second terminal of the fourth resistor and the drain of the third MOSFET; the gate of the second MOSFET is connected to the drain of the fourth MOSFET; the source of the second MOSFET serves as the output terminal of the voltage regulator and current limiter circuit; the sources of the third MOSFET and the fourth MOSFET are interconnected and grounded through the fifth resistor; The first amplifier circuit includes: a first amplifier, a sixth resistor, a seventh resistor, and an eighth resistor; wherein, the non-inverting input terminal of the first amplifier is connected to the first terminal of the fourth resistor through the sixth resistor; the inverting input terminal of the first amplifier is connected to the second terminal of the fourth resistor through the seventh resistor; the inverting input terminal of the first amplifier is also connected to the output terminal of the first amplifier through the eighth resistor; and the output terminal of the first amplifier is connected to the gate of the third MOS transistor. The second amplifier circuit includes: a second amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor; wherein, the output terminal of the second amplifier is connected to the gate of the fourth MOS transistor; the output terminal of the second amplifier is also connected to the inverting input terminal of the second amplifier through the ninth resistor; the inverting input terminal of the second amplifier is also connected to the first terminal of the tenth resistor; the second terminal of the tenth resistor is grounded through the eleventh resistor; the second terminal of the tenth resistor is also connected to the source of the second MOS transistor through the twelfth resistor; the non-inverting input terminal of the second amplifier is grounded through the thirteenth resistor; and the non-inverting input terminal of the second amplifier is also connected to the source of the second MOS transistor through the fourteenth resistor.

9. A vehicle wiring harness, characterized in that, Includes the power input protection circuit as described in any one of claims 1 to 8.

10. A vehicle-mounted system, characterized in that, Includes the power supply input protection circuit as described in any one of claims 1 to 8; Alternatively, it may include the vehicle wiring harness as described in claim 9.

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