Wide voltage input protection control circuit and vehicle-mounted terminal

Abstract

The invention relates to a wide voltage input protection control circuit and a vehicle-mounted terminal. The circuit comprises an anti-reverse connection module, an overvoltage protection module, an under-voltage protection module and a control module. The anti-reverse connection module is used for generating a polarity detection result of the vehicle-mounted power supply and performing primary on-off control on a connecting line according to the polarity detection result; the overvoltage protection module is used for generating an overvoltage detection result of the vehicle-mounted power supply, the undervoltage protection module is used for generating an undervoltage detection result of the vehicle-mounted power supply, and the control module is used for performing secondary on-off control on a connecting line according to the overvoltage detection result and the undervoltage detection result; and according to the connection line combining the first-stage on-off control and the second-stage on-off control, the vehicle-mounted power supply provides stable power supply for a post-stage circuit within a preset wide voltage input range. By adopting the method, stable and safe electric energy supply can be realized in a preset wide voltage input range, and the reliability and the service life of the vehicle-mounted terminal under complex working conditions are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power management, in particular to a wide voltage input protection control circuit and a vehicle terminal. BACKGROUND

[0002] In the field of power management, there is a need for a circuit protection for wide voltage power input of a vehicle terminal. In related protection control circuits, polarity detection and voltage detection of the power supply are achieved by simple combination of components. However, such circuits have the disadvantages of single protection condition, inability to cover wide voltage range, and high misjudgment rate, which leads to the risk of failure and damage of the subsequent circuit in complex vehicle environment. SUMMARY

[0003] Therefore, it is necessary to provide a wide voltage input protection control circuit and a vehicle terminal to solve the above technical problems.

[0004] In a first aspect, the present application provides a wide voltage input protection control circuit applied to a vehicle terminal, which comprises an anti-reverse connection module, an overvoltage protection module, an undervoltage protection module, and a control module. The power supply end of the vehicle power supply, the anti-reverse connection module, the control module, and the power receiving end of the preset subsequent circuit are sequentially connected to form a connection line between the vehicle power supply and the subsequent circuit. The power supply end of the vehicle power supply is further connected to the overvoltage protection module and the undervoltage protection module, and the controlled end of the control module is sequentially connected through the overvoltage protection module and the undervoltage protection module to form a detection control line of the control module. The anti-reverse connection module is configured to generate a polarity detection result of the vehicle power supply, and to perform one-level on-off control on the connection line according to the polarity detection result. The overvoltage protection module is configured to generate an overvoltage detection result of the vehicle power supply, the undervoltage protection module is configured to generate an undervoltage detection result of the vehicle power supply, and the control module is configured to perform two-level on-off control on the connection line according to the overvoltage detection result and the undervoltage detection result. The connection line is connected according to the one-level on-off control and the two-level on-off control, so that the vehicle power supply provides stable power supply to the subsequent circuit within a preset wide voltage input range.

[0005] In a second aspect, the present application further provides a vehicle terminal, which comprises a vehicle power supply, a subsequent circuit, and a wide voltage input protection control circuit. The wide voltage input protection control circuit comprises an anti-reverse connection module, an overvoltage protection module, an undervoltage protection module, and a control module. The power supply end of the vehicle-mounted power supply is connected to the reverse connection prevention module, the control module and the power receiving end of the post-stage circuit in sequence to form a connection line between the vehicle-mounted power supply and the post-stage circuit. The power supply end of the vehicle-mounted power supply is also connected to the overvoltage protection module and the undervoltage protection module, and the detection control line of the control module is formed in sequence through the overvoltage protection module, the undervoltage protection module and the controlled end of the control module. The reverse connection prevention module is used to generate a polarity detection result of the vehicle-mounted power supply, and to perform one-stage on-off control on the connection line according to the polarity detection result. The overvoltage protection module is used to generate an overvoltage detection result of the vehicle-mounted power supply, the undervoltage protection module is used to generate an undervoltage detection result of the vehicle-mounted power supply, and the control module is used to perform two-stage on-off control on the connection line according to the overvoltage detection result and the undervoltage detection result. The connection line is combined with the one-stage on-off control and the two-stage on-off control, so that the vehicle-mounted power supply provides stable power supply to the post-stage circuit within a preset wide voltage input range.

[0006] The wide voltage input protection control circuit and the vehicle-mounted terminal can avoid damage to the post-stage circuit caused by incorrect polarity of the power supply by performing one-stage on-off control on the connection line according to the polarity detection result of the vehicle-mounted power supply by the reverse connection prevention module. The wide voltage input protection control circuit and the vehicle-mounted terminal can also avoid damage to the post-stage circuit caused by voltage exceeding the safe range by performing two-stage on-off control on the connection line by the control module according to the voltage detection results of the vehicle-mounted power supply by the overvoltage protection module and the undervoltage protection module. Finally, the wide voltage input protection control circuit and the vehicle-mounted terminal can ensure that the vehicle-mounted power supply supplies power to the post-stage circuit only when the polarity is correct and the voltage is reasonable by performing layered safety control on the connection line according to the combination of the one-stage on-off control and the two-stage on-off control. Therefore, the wide voltage input protection control circuit and the vehicle-mounted terminal can provide stable and safe power supply within a preset wide voltage input range, and improve the reliability and service life of the vehicle-mounted terminal under complex working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments or the related art, the drawings needed in the embodiments or the related art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0008] Figure 1 The structure block diagram of the vehicle-mounted terminal in one embodiment is shown in the figure. Figure 2A structure schematic diagram of a wide voltage input protection control circuit in an embodiment. DETAILED DESCRIPTION

[0009] For the purpose, technical solutions and advantages of the present application to be more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0010] In an embodiment, as shown in the figure, a wide voltage input protection control circuit is provided, and the embodiment takes the circuit applied to a vehicle terminal 100 as an example. The circuit includes an anti-reverse connection module 101, an overvoltage protection module 102, an undervoltage protection module 103, and a control module 104. Figure 1

[0011] Specifically, the connection line between the vehicle power supply 105 and the subsequent circuit 106 is formed by sequentially passing through the power supply end of the preset vehicle power supply 105, the anti-reverse connection module 101, the control module 104, and the power receiving end of the preset subsequent circuit 106.

[0012] The power supply end of the vehicle power supply 105 is also connected to the overvoltage protection module 102 and the undervoltage protection module 103, and the detection control line of the control module 104 is formed by sequentially passing through the overvoltage protection module 102, the undervoltage protection module 103, and the controlled end of the control module 104.

[0013] Among them, the anti-reverse connection module 101 is used to generate the polarity detection result of the vehicle power supply 105, and to perform one-level on-off control on the connection line according to the polarity detection result.

[0014] Among them, the overvoltage protection module 102 is used to generate the overvoltage detection result of the vehicle power supply 105, the undervoltage protection module 103 is used to generate the undervoltage detection result of the vehicle power supply 105, and the control module 104 is used to perform two-level on-off control on the connection line according to the overvoltage detection result and the undervoltage detection result.

[0015] Among them, according to the connection line combined with one-level on-off control and two-level on-off control, the vehicle power supply 105 provides stable power supply to the subsequent circuit 106 within a preset wide voltage input range.

[0016] ​Exemplarily, the circuit is mainly used for power supply protection of the vehicle terminal 100, that is, through the hierarchical control mode, a multi-level safety barrier is formed between the vehicle power supply 105 and the subsequent circuit 106. Specifically, the power supply end of the vehicle power supply 105 first passes through the reverse connection prevention module 101, which can detect the polarity of the vehicle power supply 105 in real time. If the polarity detection result obtained by the reverse connection prevention module 101 indicates that the power supply is reversed, the reverse connection prevention module 101 immediately blocks the connection line between the vehicle power supply 105 and the subsequent circuit 106, thereby preventing the subsequent circuit 106 from being damaged due to power supply reversal. Thus, this process constitutes a first level on-off control.

[0017] Further, the vehicle power supply 105 is further connected to the subsequent circuit 106 through the control module 104, and at the same time, the power supply end of the vehicle power supply 105 is also connected in parallel to the overvoltage protection module 102 and the undervoltage protection module 103. The overvoltage protection module 102 can detect whether the power supply voltage exceeds the preset upper limit, and the undervoltage protection module 103 can detect whether the power supply voltage is lower than the preset lower limit. Specifically, if the overvoltage detection result obtained by the overvoltage protection module 102 or the undervoltage detection result obtained by the undervoltage protection module 103 indicates that the power supply voltage is out of the safe range, the control module 104 is controlled according to the detection control line to immediately block the connection line between the vehicle power supply 105 and the subsequent circuit 106, thereby preventing the subsequent circuit 106 from being damaged due to high or low voltage. Thus, this process constitutes a second level on-off control.

[0018] Based on this, through the above-mentioned hierarchical control mode, the circuit realizes dual protection of polarity detection and voltage range monitoring: on the one hand, under the action of the first level on-off control, it can prevent the damage of the subsequent circuit 106 caused by wiring error; on the other hand, under the action of the second level on-off control, it can prevent the damage of the subsequent circuit 106 caused by abnormal voltage. Thus, only in the case that the polarity of the vehicle power supply 105 is correct and the voltage is reasonable, the circuit can turn on the connection line between the vehicle power supply 105 and the subsequent circuit 106, so that the vehicle power supply 105 can still stably and safely provide power for the subsequent circuit in a wide input voltage range, meeting the use requirements of the vehicle terminal 100 under complex working conditions.

[0019] In addition, in the implementation mode, the output end of the control module 104 can be directly connected to the subsequent circuit, and can also be indirectly connected to the subsequent circuit as an input end of a Buck-Boost DC-DC converter integrated circuit. Specifically, the output voltage of the control module 104 is transmitted to the Buck-Boost DC-DC converter integrated circuit, and the transmitted voltage is converted by the Buck-Boost DC-DC converter integrated circuit to generate a target voltage suitable for a specific subsequent circuit; thus, the subsequent circuit can receive the converted target voltage through the Buck-Boost DC-DC converter integrated circuit to meet the power consumption demand of different voltage levels.

[0020] In the embodiment, on the one hand, the polarity detection result of the reverse connection prevention module on the vehicle-mounted power supply is used to perform primary on-off control on the connection line, so as to avoid damage to the subsequent circuit caused by incorrect polarity of the power supply connection line; on the other hand, the voltage detection results of the overvoltage protection module and the undervoltage protection module on the vehicle-mounted power supply are used to perform secondary on-off control on the connection line by the control module, so as to avoid damage to the subsequent circuit when the power supply voltage exceeds the safe range; finally, the connection line is controlled in layers according to the combination of the primary on-off control and the secondary on-off control, so as to ensure that the vehicle-mounted power supply supplies power to the subsequent circuit only when the polarity is correct and the voltage is reasonable; based on this, in the entire technical solution, stable and safe power supply can be realized within the preset wide voltage input range, and the reliability and service life of the vehicle-mounted terminal under complex working conditions are improved.

[0021] In one exemplary embodiment, when the polarity detection result indicates that the vehicle-mounted power supply 105 is in a positive polarity state, the reverse connection prevention module 101 is in a conduction state for driving the primary on-off control on the connection line to be in a conduction state; when the polarity detection result indicates that the vehicle-mounted power supply 105 is in a reverse polarity state, the reverse connection prevention module 101 is in a blocking state for driving the primary on-off control on the connection line to be in a blocking state.

[0022] Exemplarily, when the polarity detection result indicates that the vehicle-mounted power supply 105 is in the positive polarity state, the anti-reverse connection module 101 will automatically enter the conducting operation mode according to the polarity detection result, in which case, the primary on-off control is driven to the conducting state, and a transmissible path is established between the power supply end of the vehicle-mounted power supply 105 and the input end of the control module 104, so that the input electric energy can be smoothly transmitted. Conversely, when the polarity detection result indicates that the vehicle-mounted power supply 105 is in the reverse polarity state, the anti-reverse connection module 101 will automatically enter the blocking operation mode according to the polarity detection result, in which case, the primary on-off control is driven to the blocking state, and the path between the power supply end of the vehicle-mounted power supply 105 and the input end of the control module 104 is isolated, so that the input electric energy cannot be transmitted. As can be seen, through polarity detection and corresponding conducting or blocking response, the anti-reverse connection module 101 can complete the primary on-off control of the connection line under different power supply polarity states, so that the primary on-off control remains conducting in the positive polarity state and remains blocking in the reverse polarity state, thereby realizing the corresponding relationship between the polarity state and the primary on-off control state.

[0023] In the embodiment, on the one hand, the anti-reverse connection module enters the conducting state when the vehicle-mounted power supply is in the positive polarity state, so that the primary on-off control is driven to the conducting state; on the other hand, the anti-reverse connection module enters the blocking state when the vehicle-mounted power supply is in the reverse polarity state, so that the primary on-off control is driven to the blocking state; based on this, in the entire technical solution, the connection line can be locally conducting when the polarity is correct and locally blocking when the polarity is wrong at the anti-reverse connection level through corresponding processing of the positive and reverse polarity states of the power supply, thereby forming a reliable polarity determination and control mechanism.

[0024] In an exemplary embodiment, as shown in Figure 2 The anti-reverse connection module 101 includes a first PMOS tube Q1 and a first voltage stabilizing tube D1, and further includes a first resistor R1.

[0025] Specifically, the drain of the first PMOS tube Q1 is connected to the power supply end of the vehicle-mounted power supply 105, the source of the first PMOS tube Q1 is respectively connected to the input end of the control module 104 and the cathode of the first voltage stabilizing tube D1, the gate of the first PMOS tube Q1 is respectively connected to the anode of the first voltage stabilizing tube D1 and the input end of the first resistor R1, and the output end of the first resistor R1 is grounded.

[0026] When the polarity detection result indicates that the vehicle power supply 105 is in a positive polarity state, the first PMOS tube Q1 is in a conductive state for driving the first-level on-off control of the connection line to be in a conductive state; when the polarity detection result indicates that the vehicle power supply 105 is in a reverse polarity state, the first PMOS tube Q1 is in a blocking state for driving the first-level on-off control of the connection line to be in a blocking state. The first voltage stabilizing tube D1 is used for limiting the gate-source voltage of the first PMOS tube Q1 to be less than a preset voltage stabilizing value, and the first resistor R1 is used for providing a pull-down resistor for the gate of the first PMOS tube Q1 and a discharge path for the first voltage stabilizing tube D1.

[0027] For example, when the polarity detection result indicates that the vehicle power supply 105 is in a positive polarity state, the positive polarity of the vehicle power supply 105 is connected to the drain of the first PMOS tube Q1, so that a higher drain potential is obtained, and the source potential is gradually raised; at the same time, under the joint pull-down effect of the first resistor R1 and the first voltage stabilizing tube D1, the gate potential is stably maintained at a level lower than the source potential, so that the gate-source voltage meets the conduction condition of the first PMOS tube Q1, and thus the first PMOS tube Q1 is driven into a conductive state. In the conduction process, a stable current path is formed between the drain and the source of the first PMOS tube Q1, so that electric energy can be transmitted from the power supply end of the vehicle power supply 105 to the input end of the control module 104, so that the first-level on-off control of the connection line is placed in a conductive state.

[0028] In addition, in order to ensure that there is no excessive voltage difference between the gate and the source in the conduction process, the first voltage stabilizing tube D1 bears the function of voltage limiting; that is, if the gate-source voltage is too large, when the reverse voltage in the first voltage stabilizing tube D1 rises to the preset voltage stabilizing value, the first voltage stabilizing tube D1 limits the gate-source voltage to be always constrained within the preset safe range by means of constant voltage clamping, so as to ensure that the first PMOS tube Q1 can still work stably under high voltage conditions and avoid device damage. For example, when the wide voltage input range of the vehicle power supply 105 corresponds to 9V to 31V, the voltage stabilizing value of the first voltage stabilizing tube D1 is set to 15V, so that the gate-source voltage of the first PMOS tube Q1 is always limited to be below 15V, so as to ensure that the first PMOS tube Q1 works normally.

[0029] Exemplarily, when the polarity detection result indicates that the vehicle-mounted power supply 105 is in the reverse polarity state, the drain of the first PMOS tube Q1 is accessed by the reverse polarity of the vehicle-mounted power supply 105, so that the drain potential and the source potential are low, thereby causing the gate-source voltage to not satisfy the conduction condition of the first PMOS tube Q1, and thus the first PMOS tube Q1 is driven into the blocking state. In the blocking process, the current path between the drain and the source of the first PMOS tube Q1 is completely cut off, so that the electric energy cannot be transmitted from the power supply end of the vehicle-mounted power supply 105 to the input end of the control module 104, thereby causing the primary on-off control of the connection line to be in the blocking state.

[0030] In the embodiment, on the one hand, the first PMOS tube is driven into the conduction state when the vehicle-mounted power supply is in the forward polarity state, so that the primary on-off control is in the conduction state; on the other hand, the first PMOS tube is driven into the blocking state when the vehicle-mounted power supply is in the reverse polarity state, so that the primary on-off control is in the blocking state; further, the first zener tube limits the gate-source voltage of the first PMOS tube, so that the gate-source voltage is prevented from exceeding the preset zener value and is kept in the safe range; based on this, in the entire technical solution, the reliable switching of the primary on-off control under different polarity states can be realized by automatic judgment and control of the positive and negative polarities of the power supply and stable constraint of the gate-source voltage, and the stability and safety in the circuit working process are ensured.

[0031] In one exemplary embodiment, when the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in the overvoltage state, the control module 104 is in the blocking state for driving the secondary on-off control of the connection line to be in the blocking state; when the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in the non-overvoltage state and the undervoltage detection result indicates that the vehicle-mounted power supply 105 is in the undervoltage state, the control module 104 is in the blocking state for driving the secondary on-off control of the connection line to be in the blocking state; when the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in the non-overvoltage state and the undervoltage detection result indicates that the vehicle-mounted power supply 105 is in the non-undervoltage state, the control module 104 is in the conduction state for driving the secondary on-off control of the connection line to be in the conduction state.

[0032] Exemplarily, when the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in an overvoltage state, the control module 104 automatically enters the blocked operation mode according to the overvoltage detection result, in which case, the secondary on-off control is driven to the blocked state, and the path between the output end of the anti-reverse connection module 101 and the power receiving end of the subsequent circuit 106 is isolated, so that the input electric energy cannot be transmitted. Further, when the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in an overvoltage state, and the undervoltage detection result indicates that the vehicle-mounted power supply 105 is in an undervoltage state, the control module 104 automatically enters the blocked operation mode according to the undervoltage detection result, in which case, the secondary on-off control is driven to the blocked state, and the path between the output end of the anti-reverse connection module 101 and the power receiving end of the subsequent circuit 106 is isolated, so that the input electric energy cannot be transmitted. Further, when the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in an undervoltage state, and the undervoltage detection result indicates that the vehicle-mounted power supply 105 is in an undervoltage state, the control module 104 automatically enters the on operation mode according to the overvoltage detection result, in which case, the secondary on-off control is driven to the on state, and the path between the output end of the anti-reverse connection module 101 and the power receiving end of the subsequent circuit 106 is established to be a transmittable path, so that the input electric energy can be smoothly transmitted.

[0033] As can be seen, through voltage detection and corresponding on or blocked response, the control module 104 can complete secondary on-off control of the connection line under different voltage states, so that the secondary on-off control remains on in a normal voltage state, and remains blocked in an overvoltage or undervoltage state, thereby realizing the corresponding relationship between the voltage state and the secondary on-off control state.

[0034] In this embodiment, on the one hand, the control module enters the on state when the vehicle-mounted power supply is in a normal state, so that the secondary on-off control is driven to the on state; on the other hand, the control module enters the blocked state when the vehicle-mounted power supply is in an overvoltage or undervoltage state, so that the secondary on-off control is driven to the blocked state; based on this, in the entire technical solution, the connection line can be locally on in a normal voltage state and locally blocked in an abnormal voltage state at the voltage detection level through corresponding processing of the power supply voltage state, thereby forming a reliable voltage determination and control mechanism.

[0035] In an exemplary embodiment, as shown in Figure 2 The overvoltage protection module 102 further includes a first fixed voltage division structure, a first dynamic voltage division structure, a first voltage comparator U1, and a first NPN transistor Q2.

[0036] Specifically, the input end of the first fixed voltage division structure is connected to the power supply end of the vehicle-mounted power supply 105, the output end of the first fixed voltage division structure is respectively connected to the input end of the first dynamic voltage division structure and the input end of the first voltage comparator U1, and the output end of the first dynamic voltage division structure is grounded.

[0037] The output end of the first voltage comparator U1 is connected to the base of the first NPN transistor Q2, and the ground end of the first voltage comparator U1 is grounded, the collector of the first NPN transistor Q2 is connected to the input end of the undervoltage protection module 103, and the emitter of the first NPN transistor Q2 is grounded.

[0038] The first fixed voltage division structure and the first dynamic voltage division structure are used to jointly adjust the first to-be-detected voltage input by the vehicle-mounted power supply 105 to the first voltage comparator U1; the first fixed voltage division structure includes the second resistor R2 and the third resistor R3 which are arranged in parallel and have fixed resistance values, and the second fixed voltage division structure includes the fourth resistor R4 and the fifth resistor R5 which are arranged in parallel and have variable resistance values.

[0039] The overvoltage protection module 102 further includes a first capacitor C1 and a sixth resistor R6. The first capacitor C1 is connected in parallel with the first dynamic voltage division structure to filter and buffer the voltage division output; the sixth resistor R6 has two ends connected to the output end of the first voltage comparator U1 and the base of the first NPN transistor Q2 respectively to provide current limiting protection for the base of the first NPN transistor Q2.

[0040] The first voltage comparator U1 is used to compare the first to-be-detected voltage with a preset first reference voltage to generate an overvoltage detection result.

[0041] On the one hand, if the first to-be-detected voltage is greater than the first reference voltage, the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in an overvoltage state, the first voltage comparator U1 outputs a high-level signal, and the first NPN transistor Q2 is in a conducting state according to the high-level signal to intervene in the undervoltage detection result of the undervoltage protection module 103 to drive the undervoltage protection module 103 to control the control module 104 to be in a blocking state.

[0042] On the other hand, if the first to-be-detected voltage is less than or equal to the first reference voltage, the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in an undervoltage state, the first voltage comparator U1 outputs a low-level signal, and the first NPN transistor Q2 is in a blocking state according to the low-level signal to block the intervention in the undervoltage detection result of the undervoltage protection module 103 to drive the undervoltage protection module 103 to autonomously control the working state of the control module 104 according to the undervoltage detection result.

[0043] Exemplarily, when the first fixed voltage dividing structure and the first dynamic voltage dividing structure jointly act, the voltage of the input vehicle power supply 105 is processed into a first to-be-detected voltage and sent to the input end of the first voltage comparator U1; at the same time, the first voltage comparator U1 internally stores a preset first reference voltage as a reference for judging whether the vehicle power supply 105 exceeds the upper limit of safety. For example, if the first reference voltage stored in the first voltage comparator U1 is 2.93V, and the upper threshold of the wide voltage input range corresponding to the vehicle power supply 105 is 31V, the resistance of the first dynamic voltage dividing structure can be adjusted so that the original voltage input of 31V is converted into a 2.93V voltage input to the first voltage comparator U1 under the voltage dividing action of the first fixed voltage dividing structure and the first dynamic voltage dividing structure, thereby completing the calibration of the first dynamic voltage dividing structure and ensuring subsequent overvoltage detection based on the upper threshold of 31V. Based on this, the resistance of the first dynamic voltage dividing structure can be dynamically adjusted to adapt to the upper threshold of the actual wide voltage input range, thereby realizing the flexible definition function of the voltage detection range.

[0044] Optionally, when the actual input first to-be-detected voltage is greater than the first reference voltage, the first voltage comparator U1 outputs a high-level signal after comparing the two, and transmits it to the base of the first NPN transistor Q2; after the base of the first NPN transistor Q2 receives the high-level signal, the first NPN transistor Q2 enters the conduction state to form a conduction path between the collector and the emitter of the first NPN transistor Q2. In this state, because the collector of the first NPN transistor Q2 is connected to the input end of the undervoltage protection module 103, and the emitter is grounded, thereby pulling down the potential of the input end of the undervoltage protection module 103, based on this, the overvoltage detection result of the overvoltage protection module 102 is introduced into the input path of the undervoltage protection module 103 through the conduction of the first NPN transistor Q2, realizing the intervention on the original detection result of the undervoltage protection module 103. In this case, the undervoltage protection module 103 no longer only depends on its own judgment of the power supply undervoltage condition to determine the output, but will be affected by the overvoltage detection result and be forced to output an explicit control instruction to make the control module 104 enter the blocking state.

[0045] Optionally, when the actual input first voltage to be detected is less than or equal to the first reference voltage, the first voltage comparator U1 outputs a low-level signal after comparing the two, and transmits the low-level signal to the base of the first NPN transistor Q2; after the base of the first NPN transistor Q2 receives the low-level signal, the first NPN transistor Q2 enters a blocking state, so that no conduction path is formed between the collector and the emitter of the first NPN transistor Q2. In this state, the potential at the input end of the undervoltage protection module 103 is not pulled low, and based on this, the overvoltage detection result of the overvoltage protection module 102 is not introduced into the input path of the undervoltage protection module 103 through the first NPN transistor Q2, so that the original detection result of the undervoltage protection module 103 is no longer intervened. In this case, the undervoltage protection module restores the function of independent decision-making, and only determines the output according to its own judgment of the power supply undervoltage condition, that is, autonomously determines whether the control module 104 enters a blocking state or a conduction state according to the undervoltage detection result.

[0046] In the embodiment, on the one hand, when the first voltage to be detected is greater than the first reference voltage, the first voltage comparator outputs a high-level signal and drives the first NPN transistor to conduct, so that the detection result of the undervoltage protection module is intervened, and the control module is prompted to enter a blocking state; on the other hand, when the first voltage to be detected is less than or equal to the first reference voltage, the voltage comparator outputs a low-level signal and drives the first NPN transistor to block, so as to avoid intervention on the detection result of the undervoltage protection module, so that the undervoltage protection module can perform voltage detection and control the state of the control module according to its own logic; based on this, in the entire technical solution, intervention on the undervoltage detection under the overvoltage condition is realized to forcibly block the control module, and the undervoltage detection under the non-overvoltage condition is released, so that the control module is reasonably driven under different voltage states, and the response ability of distinguishing overvoltage and non-overvoltage is ensured for the secondary on-off control.

[0047] In one exemplary embodiment, as shown in Figure 2 The undervoltage protection module 103 further includes a second fixed voltage division structure, a second dynamic voltage division structure, a second voltage comparator U2, a second zener D2, and a second NPN transistor Q3.

[0048] The input end of the second fixed voltage dividing structure is connected to the power supply end of the vehicle-mounted power supply 105, the output end of the second fixed voltage dividing structure is connected to the input end of the second dynamic voltage dividing structure, the input end of the second voltage comparator U2, the cathode of the second voltage stabilizing tube D2 and the output end of the overvoltage protection module respectively, the output end of the second dynamic voltage dividing structure is grounded, and the ground end of the second voltage comparator U2 is connected to the anode of the second voltage stabilizing tube D2 and the ground respectively. Further, the collector of the first NPN transistor Q2 in the overvoltage protection module 102 is connected to the output end of the second fixed voltage dividing structure and the input end of the second dynamic voltage dividing structure respectively.

[0049] The second fixed voltage dividing structure and the second dynamic voltage dividing structure are used to jointly adjust the second voltage to be detected input by the vehicle-mounted power supply 105 to the second voltage comparator U2; the second fixed voltage dividing structure includes the seventh resistor R7 and the eighth resistor R8 which are arranged in parallel and have fixed resistance values, and the ninth resistor R9 and the tenth resistor R10 which are arranged in parallel and have variable resistance values.

[0050] The under-voltage protection module 103 further includes a second capacitor C2, a third capacitor C3, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14. The second capacitor C2 is connected in parallel with the second dynamic voltage dividing structure to filter and buffer the voltage dividing output; the two ends of the eleventh resistor R11 are connected to the output end of the second voltage comparator U2 and the base of the second NPN transistor Q3 respectively to provide current limiting protection for the base of the second NPN transistor Q3; the twelfth resistor R12 and the thirteenth resistor R13 are connected in series between the power supply end of the vehicle-mounted power supply 105 and the collector of the second NPN transistor Q3 to function as voltage dividing; the two ends of the fourteenth resistor R14 are connected to the input end of the thirteenth resistor R13 and the controlled end of the control module 104 respectively to function as current limiting; and the two ends of the third capacitor C3 are connected to the input end of the twelfth resistor R12 and the input end of the fourteenth resistor R14 respectively to provide transient current buffer and form a filter network with the surrounding resistors.

[0051] The second voltage comparator U2 is used to compare the second voltage to be detected with a preset second reference voltage to generate an under-voltage detection result.

[0052] The second voltage stabilizer D2 is used to limit the second to-be-detected voltage to not exceed a preset voltage stabilization value, that is, if the second to-be-detected voltage is too large, until the reverse voltage in the second voltage stabilizer D2 rises to the preset voltage stabilization value, the second voltage stabilizer D2 limits the second to-be-detected voltage to be always constrained in a preset safe range through constant voltage clamping, so as to ensure that the second voltage comparator U2 can still work stably under high voltage condition and avoid device damage. For example, when the wide voltage input range of the vehicle-mounted power supply 105 corresponds to 9V to 31V, and the second reference voltage of the second voltage comparator U2 is 2.93V, the voltage stabilization value of the second voltage stabilizer D2 is set to 5.6V, so that the input end voltage of the second voltage comparator U2 is always limited to below 5.6V, but does not affect its under-voltage detection, so as to ensure that the second voltage comparator U2 works normally.

[0053] On the one hand, when the over-voltage detection result indicates that the vehicle-mounted power supply 105 is in an over-voltage state, the over-voltage protection module controls the second to-be-detected voltage to be less than the second reference voltage, then the second voltage comparator U2 outputs a low-level signal, and the second NPN transistor Q3 is in a blocking state according to the low-level signal, so as to control the control module 104 to be in a blocking state.

[0054] On the other hand, when the over-voltage detection result indicates that the vehicle-mounted power supply 105 is in an under-voltage state, if the second to-be-detected voltage is less than the second reference voltage, the under-voltage detection result indicates that the vehicle-mounted power supply 105 is in an under-voltage state, the second voltage comparator U2 outputs a low-level signal, and the second NPN transistor Q3 is in a blocking state according to the low-level signal, so as to control the control module 104 to be in a blocking state.

[0055] On the other hand, when the over-voltage detection result indicates that the vehicle-mounted power supply 105 is in an under-voltage state, if the second to-be-detected voltage is less than the second reference voltage, the under-voltage detection result indicates that the vehicle-mounted power supply 105 is in an under-voltage state, the second voltage comparator U2 outputs a low-level signal, and the second NPN transistor Q3 is in a blocking state according to the low-level signal, so as to control the control module 104 to be in a blocking state.

[0056] Exemplarily, after the second fixed voltage division structure and the second dynamic voltage division structure jointly act, the voltage of the input vehicle power supply 105 is processed into a second to-be-detected voltage and is sent to the input end of the second voltage comparator U2; at the same time, the second voltage comparator U2 internally stores a preset second reference voltage as a reference for judging whether the vehicle power supply 105 is lower than a lower limit of a safety range. For example, if the second reference voltage stored in the second voltage comparator U2 is 2.93V and the lower limit threshold of the wide voltage input range corresponding to the vehicle power supply 105 is 9V, the resistance of the second dynamic voltage division structure can be adjusted so that the original voltage input of 9V is converted into a voltage input of 2.93V to the second voltage comparator U2 under the voltage division of the second fixed voltage division structure and the second dynamic voltage division structure, thereby completing the calibration of the second dynamic voltage division structure and ensuring that the subsequent undervoltage detection is based on the lower limit threshold of 9V. Based on this, the resistance of the second dynamic voltage division structure can be dynamically adjusted to adapt to the lower limit threshold of the actual wide voltage input range, thereby realizing the flexible definition function of the voltage detection range.

[0057] Optionally, when the overvoltage detection result indicates that the vehicle power supply 105 is in an overvoltage state, the first NPN transistor Q2 in the conducting state pulls down the potential at the input end of the second voltage comparator U2, based on which the second to-be-detected voltage received by the second voltage comparator U2 is limited to a level less than the second reference voltage. Thus, after comparing the two, the second voltage comparator U2 outputs a low-level signal and transmits it to the base of the second NPN transistor Q3. After the base of the second NPN transistor Q3 receives the low-level signal, the second NPN transistor Q3 enters a blocking state so that no conduction path is formed between the collector and the emitter of the second NPN transistor Q3. In this state, the undervoltage protection module 103 is driven to output an explicit control instruction to the outside so that the control module 104 enters a blocking state.

[0058] Optionally, when the overvoltage detection result indicates that the vehicle power supply 105 is in an overvoltage state, the first NPN transistor Q2 in the conducting state pulls down the potential at the input end of the second voltage comparator U2, based on which the second to-be-detected voltage received by the second voltage comparator U2 is limited to a level less than the second reference voltage. Thus, after comparing the two, the second voltage comparator U2 outputs a low-level signal and transmits it to the base of the second NPN transistor Q3. After the base of the second NPN transistor Q3 receives the low-level signal, the second NPN transistor Q3 enters a blocking state so that no conduction path is formed between the collector and the emitter of the second NPN transistor Q3. In this state, the undervoltage protection module 103 is driven to output an explicit control instruction to the outside so that the control module 104 enters a blocking state.

[0059] Further, when the actually input second voltage to be detected is greater than or equal to the second reference voltage, the second voltage comparator U1 outputs a high level signal after comparing the two, and transmits the high level signal to the base of the second NPN transistor Q3; after the base of the second NPN transistor Q3 receives the high level signal, the second NPN transistor Q3 enters the conducting state, so that a conducting path is formed between the collector and the emitter of the second NPN transistor Q3. In this state, the overvoltage protection module 103 outputs an explicit control instruction according to the overvoltage detection result of the overvoltage protection module 103, so that the control module 104 enters the conducting state.

[0060] In the embodiment, on the one hand, when the overvoltage detection result is overvoltage, the second voltage to be detected is controlled to be less than the second reference voltage, the second voltage comparator outputs a low level signal and drives the second NPN transistor to block, so that the control module enters the blocking state; on the other hand, when the overvoltage detection result is not overvoltage and the second voltage to be detected is less than the second reference voltage, the second voltage comparator outputs a low level signal and drives the second NPN transistor to block, so that the control module enters the blocking state; on the other hand, when the overvoltage detection result is not overvoltage and the second voltage to be detected is greater than or equal to the second reference voltage, the second voltage comparator outputs a high level signal and drives the second NPN transistor to conduct, so that the control module enters the conducting state; based on this, in the whole technical solution, the intervention of the overvoltage condition to the under-voltage detection is realized to forcibly block the control module, and the autonomous determination of the under-voltage detection under the non-overvoltage condition is realized, so that the control module is reasonably driven under different voltage states, and the hierarchical response ability of distinguishing overvoltage and non-overvoltage, and under-voltage and non-under-voltage under the non-overvoltage condition is ensured for the secondary on-off control.

[0061] In an exemplary embodiment, as shown in Figure 2 The control module 104 includes a second PMOS tube Q4 and a third zener D3.

[0062] Specifically, the source of the second PMOS tube Q4 is connected to the output end of the anti-reverse connection module 101 and the cathode of the third zener D3, respectively, the drain of the second PMOS tube Q4 is connected to the power receiving end of the subsequent circuit, and the gate of the second PMOS tube Q4 is connected to the output end of the overvoltage protection module 103 and the anode of the third zener D3, respectively. Further, the source of the second PMOS tube Q4 is connected to the source of the first PMOS tube Q1 in the anti-reverse connection module 101, and the gate of the second PMOS tube Q4 is connected to the input end of the fourteenth resistor R14 in the overvoltage protection module 103.

[0063] On the one hand, when the overvoltage detection result indicates that the vehicle-mounted power supply 105 is in the overvoltage state, the second PMOS tube Q4 is in the blocking state, so as to drive the secondary on-off control of the connection line to be in the blocking state.

[0064] In another aspect, when the overvoltage detection result indicates that the vehicle power supply 105 is in the non-overvoltage state and the undervoltage detection result indicates that the vehicle power supply 105 is in the undervoltage state, the second PMOS transistor Q4 is in the blocking state for driving the secondary on-off control of the connection line to be in the blocking state.

[0065] In another aspect, when the overvoltage detection result indicates that the vehicle power supply 105 is in the non-overvoltage state and the undervoltage detection result indicates that the vehicle power supply 105 is in the non-undervoltage state, the second PMOS transistor Q4 is in the conducting state for driving the secondary on-off control of the connection line to be in the conducting state.

[0066] Exemplarily, when the overvoltage detection result indicates that the vehicle power supply 105 is in the overvoltage state, the first NPN transistor Q2 in the conducting state in the overvoltage protection module 102 makes the second to-be-detected voltage less than the second reference voltage, and the second voltage comparator U2 in the undervoltage protection module 103 outputs a low-level signal to make the second NPN transistor Q3 in the blocking state. In this state, the gate potential of the second PMOS transistor Q4 is not pulled low, so that the gate-source voltage of the second PMOS transistor Q4 does not meet the conducting condition of the second PMOS transistor Q4, and therefore the second PMOS transistor Q4 is driven into the blocking state. In the blocking process, the current path between the drain and the source of the second PMOS transistor Q4 is completely cut off, so that the electric energy cannot be transmitted from the output end of the reverse connection prevention module 101 to the power receiving end of the subsequent circuit 106, thereby making the secondary on-off control of the connection line be in the blocking state.

[0067] Exemplarily, when the overvoltage detection result indicates that the vehicle power supply 105 is in the non-overvoltage state and the undervoltage detection result indicates that the vehicle power supply 105 is in the undervoltage state, the second to-be-detected voltage is less than the second reference voltage, and the second voltage comparator U2 in the undervoltage protection module 103 outputs a low-level signal to make the second NPN transistor Q3 in the blocking state. In this state, the gate potential of the second PMOS transistor Q4 is not pulled low, so that the gate-source voltage of the second PMOS transistor Q4 does not meet the conducting condition of the second PMOS transistor Q4, and therefore the second PMOS transistor Q4 is driven into the blocking state. In the blocking process, the current path between the drain and the source of the second PMOS transistor Q4 is completely cut off, so that the electric energy cannot be transmitted from the output end of the reverse connection prevention module 101 to the power receiving end of the subsequent circuit 106, thereby making the secondary on-off control of the connection line be in the blocking state.

[0068] For example, when the overvoltage detection result indicates that the vehicle power supply 105 is not in an overvoltage state, and the undervoltage detection result indicates that the vehicle power supply 105 is not in an undervoltage state, the second voltage to be detected is greater than or equal to the second reference voltage. The second voltage comparator U2 in the undervoltage protection module 103 outputs a high-level signal to make the second NPN transistor Q3 turn on. In this state, the gate potential of the second PMOS transistor Q4 is pulled low and stably maintained at a level lower than the source potential, so that the gate-source voltage of the second PMOS transistor Q4 meets the turn-on condition of the second PMOS transistor Q4, and therefore the second PMOS transistor Q4 is driven into the turn-on state. During the turn-on process, a stable current path is formed between the drain and source of the second PMOS transistor Q4, so that electrical energy can be transferred from the output terminal of the reverse connection protection module 101 to the receiving terminal of the subsequent circuit 106, thereby putting the secondary on / off control of the connection line into the turn-on state.

[0069] In addition, to ensure that there is no excessive voltage difference between the gate and the source during the conduction process, the third Zener diode D3 performs the function of voltage limiting; that is, if the gate-source voltage is too high, until the reverse voltage in the third Zener diode D3 rises to the preset regulated value, the third Zener diode D3 limits the gate-source voltage to always be constrained within the preset safe range by constant voltage clamping, so as to ensure that the second PMOS transistor Q4 can still work stably under high voltage conditions and avoid device damage.

[0070] In addition, for example Figure 2 As shown, the circuit also includes a fourth capacitor C4, a fifth capacitor C5, and a bidirectional Zener diode ZD1. One end of these components is connected between the power supply terminal of the vehicle power supply 105 and the drain of the first PMOS transistor Q1, and the other end is grounded. Among them, the fourth capacitor C4 and the fifth capacitor C5 are used to provide power filtering capacitors for the input of the vehicle power supply 105, and the bidirectional Zener diode ZD1 is used to provide voltage clamping protection for the input of the vehicle power supply 105.

[0071] In this embodiment, on the one hand, when the vehicle power supply is in an overvoltage state or under overvoltage conditions, the second PMOS transistor is driven to the blocking state, thereby keeping the secondary on / off control in the blocking state. On the other hand, when the vehicle power supply is in a normal voltage state, the second PMOS transistor is driven to the conducting state, thereby keeping the secondary on / off control in the conducting state. Furthermore, based on the limiting effect of the third Zener diode on the gate-source voltage of the second PMOS transistor, the gate-source voltage is prevented from exceeding the preset regulated value and kept within a safe range. Based on this, in the entire technical solution, the reliable switching of the secondary on / off control under different voltage states can be achieved through automatic determination and control of the power supply voltage and stable constraint of the gate-source voltage, ensuring the stability and safety of the circuit during operation.

[0072] The modules in the wide voltage input protection control circuit can be implemented by software, hardware, or a combination thereof. The modules can be embedded in or independent of a processor in a computer device in hardware form, or stored in a memory in the computer device in software form, so as to be called and executed by the processor.

[0073] In an exemplary embodiment, based on the same inventive concept, a vehicle terminal 100 comprising the wide voltage input protection control circuit according to any of the above embodiments is also provided. As shown in Figure 1 The vehicle terminal 100 comprises an anti-reverse connection module 101, an overvoltage protection module 102, an undervoltage protection module 103, a control module 104, a vehicle power supply 105, and a post-stage circuit 106.

[0074] The implementation scheme for solving the problem provided by the vehicle terminal is similar to the implementation scheme described in the above circuit, and therefore one or more vehicle terminal embodiments with the vehicle terminal as the execution subject can be derived from any of the above circuit embodiments. The specific limitations in the vehicle terminal embodiments can be referred to the limitations of the wide voltage input protection control circuit described above, and will not be described here.

[0075] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not contradict, they should be considered as within the scope of the present disclosure.

[0076] The above embodiments only express several implementation manners of the present application, and the description is specific and detailed, but it should not be considered as a limitation on the scope of the patent of the present application. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A wide voltage input protection control circuit, characterized in that, The circuit, which is used in vehicle terminals, includes a reverse connection protection module, an overvoltage protection module, an undervoltage protection module, and a control module. The connection line between the vehicle power supply and the downstream circuit is formed sequentially through the power supply terminal of the preset vehicle power supply, the reverse connection protection module, the control module, and the power receiving terminal of the preset downstream circuit. The power supply terminal of the vehicle power supply is also connected to the overvoltage protection module and the undervoltage protection module respectively, and sequentially through the overvoltage protection module, the undervoltage protection module and the controlled terminal of the control module to form a detection and control circuit for the control module; The reverse connection protection module is used to generate the polarity detection result of the vehicle power supply and to perform first-level on / off control of the connection line based on the polarity detection result. The overvoltage protection module is used to generate the overvoltage detection result of the vehicle power supply, the undervoltage protection module is used to generate the undervoltage detection result of the vehicle power supply, and the control module is used to perform two-stage on / off control of the connection line based on the overvoltage detection result and the undervoltage detection result. Specifically, the connection line combining the first-level on / off control and the second-level on / off control enables the vehicle power supply to provide stable power to the downstream circuit within a preset wide voltage input range.

2. The circuit according to claim 1, characterized in that, When the polarity detection result indicates that the vehicle power supply is in a positive polarity state, the reverse connection protection module is in a conducting state to drive the first-level on / off control of the connection line to be in a conducting state. When the polarity detection result indicates that the vehicle power supply is in a reverse polarity state, the reverse connection protection module is in a blocking state to drive the first-level on / off control of the connection line to be in a blocking state.

3. The circuit according to claim 2, characterized in that, The reverse connection protection module includes a first PMOS transistor and a first Zener diode; The drain of the first PMOS transistor is connected to the power supply terminal of the vehicle power supply, the source of the first PMOS transistor is connected to the input terminal of the control module and the cathode of the first Zener diode, and the gate of the first PMOS transistor is connected to the anode of the first Zener diode. Specifically, when the polarity detection result indicates that the vehicle power supply is in a positive polarity state, the first PMOS transistor is in a conducting state to drive the first-stage on / off control of the connection line to be in a conducting state; when the polarity detection result indicates that the vehicle power supply is in a reverse polarity state, the first PMOS transistor is in a blocking state to drive the first-stage on / off control of the connection line to be in a blocking state. The first Zener diode is used to limit the gate-source voltage of the first PMOS transistor from exceeding a preset regulated value.

4. The circuit according to claim 1, characterized in that, When the overvoltage detection result indicates that the vehicle power supply is in an overvoltage state, the control module is in a blocking state to drive the secondary on / off control of the connection line to be in a blocking state. When the overvoltage detection result indicates that the vehicle power supply is not overvoltaged, and the undervoltage detection result indicates that the vehicle power supply is undervoltaged, the control module is in a blocking state to drive the secondary on / off control of the connection line to be in a blocking state. When the overvoltage detection result indicates that the vehicle power supply is not overvoltaged, and the undervoltage detection result indicates that the vehicle power supply is not undervoltaged, the control module is in the conducting state to drive the secondary on / off control of the connection line to be in the conducting state.

5. The circuit according to claim 4, characterized in that, The overvoltage protection module further includes a first fixed voltage divider structure, a first dynamic voltage divider structure, a first voltage comparator, and a first NPN transistor; The input terminal of the first fixed voltage divider structure is connected to the power supply terminal of the vehicle power supply, the output terminal of the first fixed voltage divider structure is connected to the input terminal of the first dynamic voltage divider structure and the input terminal of the first voltage comparator, and the output terminal of the first dynamic voltage divider structure is grounded. The output terminal of the first voltage comparator is connected to the base of the first NPN transistor, the collector of the first NPN transistor is connected to the input terminal of the undervoltage protection module, and the emitter of the first NPN transistor is grounded. Wherein, the first fixed voltage divider structure and the first dynamic voltage divider structure are used to jointly adjust the first voltage to be detected input from the vehicle power supply to the first voltage comparator; The first voltage comparator is used to compare the first voltage to be detected with a preset first reference voltage to generate an overvoltage detection result. If the first voltage to be detected is greater than the first reference voltage, the overvoltage detection result indicates that the vehicle power supply is in an overvoltage state. The first voltage comparator outputs a high-level signal, and the first NPN transistor is in a conducting state according to the high-level signal, so as to intervene in the undervoltage detection result of the undervoltage protection module and drive the undervoltage protection module to control the control module to be in a blocking state. If the first voltage to be detected is less than or equal to the first reference voltage, the overvoltage detection result indicates that the vehicle power supply is not overvoltaged. The first voltage comparator outputs a low-level signal, and the first NPN transistor is in a blocking state according to the low-level signal, so as to block the interference of the undervoltage detection result of the undervoltage protection module, and drive the undervoltage protection module to autonomously control the working state of the control module according to the undervoltage detection result.

6. The circuit according to claim 4, characterized in that, The undervoltage protection module also includes a second fixed voltage divider structure, a second dynamic voltage divider structure, a second voltage comparator, a second Zener diode, and a second NPN transistor. The input terminal of the second fixed voltage divider structure is connected to the power supply terminal of the vehicle power supply. The output terminal of the second fixed voltage divider structure is connected to the input terminal of the second dynamic voltage divider structure, the input terminal of the second voltage comparator, the cathode of the second Zener diode, and the output terminal of the overvoltage protection module. The output terminal of the second dynamic voltage divider structure is connected to the anode of the second Zener diode and ground. The second fixed voltage divider structure and the second dynamic voltage divider structure are used to jointly adjust the second voltage to be detected input from the vehicle power supply to the second voltage comparator. The second voltage comparator is used to compare the second voltage to be detected with a preset second reference voltage to generate an undervoltage detection result. The second Zener diode is used to limit the second voltage to be detected from not exceeding a preset regulated voltage value. When the overvoltage detection result indicates that the vehicle power supply is in an overvoltage state, the overvoltage protection module controls the second voltage to be detected to be less than the second reference voltage. Then, the second voltage comparator outputs a low-level signal, and the second NPN transistor is in a blocking state according to the low-level signal, so as to control the control module to be in a blocking state. When the overvoltage detection result indicates that the vehicle power supply is not overvoltaged, if the second voltage to be detected is less than the second reference voltage, then the undervoltage detection result indicates that the vehicle power supply is undervoltaged. The second voltage comparator outputs a low-level signal, and the second NPN transistor is in a blocking state according to the low-level signal, so as to control the control module to be in a blocking state. When the overvoltage detection result indicates that the vehicle power supply is not overvoltaged, if the second voltage to be detected is greater than or equal to the second reference voltage, then the undervoltage detection result indicates that the vehicle power supply is not undervoltaged. The second voltage comparator outputs a high-level signal, and the second NPN transistor is turned on according to the high-level signal to control the control module to be turned on.

7. The circuit according to claim 4, characterized in that, The control module includes a second PMOS transistor and a third Zener diode; The source of the second PMOS transistor is connected to the output terminal of the reverse connection protection module and the cathode of the third Zener diode, the drain of the second PMOS transistor is connected to the power receiving terminal of the subsequent circuit, and the gate of the second PMOS transistor is connected to the output terminal of the undervoltage protection module and the anode of the third Zener diode. When the overvoltage detection result indicates that the vehicle power supply is in an overvoltage state, the second PMOS transistor is in a blocking state to drive the secondary on / off control of the connection line to be in a blocking state. When the overvoltage detection result indicates that the vehicle power supply is not overvoltaged, and the undervoltage detection result indicates that the vehicle power supply is undervoltaged, the second PMOS transistor is in a blocking state to drive the secondary on / off control of the connection line to be in a blocking state. When the overvoltage detection result indicates that the vehicle power supply is not overvoltaged, and the undervoltage detection result indicates that the vehicle power supply is not undervoltaged, the second PMOS transistor is in the on state to drive the secondary on / off control of the connection line to be in the on state. The third Zener diode is used to limit the gate-source voltage of the second PMOS transistor from exceeding a preset regulated value.

8. A vehicle-mounted terminal, characterized in that, The vehicle terminal includes a vehicle power supply, a downstream circuit, and a wide voltage input protection control circuit as described in any one of claims 1 to 7. The wide voltage input protection control circuit includes a reverse connection protection module, an overvoltage protection module, an undervoltage protection module, and a control module. The connection line between the vehicle power supply and the subsequent circuit is formed sequentially through the power supply terminal of the vehicle power supply, the reverse connection protection module, the control module, and the power receiving terminal of the subsequent circuit. The power supply terminal of the vehicle power supply is also connected to the overvoltage protection module and the undervoltage protection module respectively, and sequentially through the overvoltage protection module, the undervoltage protection module and the controlled terminal of the control module to form a detection and control circuit for the control module; The reverse connection protection module is used to generate the polarity detection result of the vehicle power supply and to perform first-level on / off control of the connection line based on the polarity detection result. The overvoltage protection module is used to generate the overvoltage detection result of the vehicle power supply, the undervoltage protection module is used to generate the undervoltage detection result of the vehicle power supply, and the control module is used to perform two-stage on / off control of the connection line based on the overvoltage detection result and the undervoltage detection result. Specifically, the connection line combining the first-level on / off control and the second-level on / off control enables the vehicle power supply to provide stable power to the downstream circuit within a preset wide voltage input range.

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