Overcurrent protection circuit, load power supply circuit, and vehicle

Abstract

This application provides an overcurrent protection circuit, a load power supply circuit, and a vehicle, belonging to the field of battery protection technology. It includes a switching module, a signal amplification module, and a comparison output module. Both the switching module and the signal amplification module are connected to the power supply circuit. The signal amplification module amplifies the voltage of the power supply circuit to obtain a voltage amplification signal. The comparison output module is connected to the signal amplification module and is configured to receive the voltage amplification signal and output a shutdown signal to the switching module when the voltage amplification signal is greater than or equal to a preset threshold voltage of the power supply circuit. The overcurrent protection circuit provided in this application can disconnect the load device in the power supply circuit when a grounding failure occurs during the use of the power supply circuit, preventing large current from flowing to the load device and avoiding damage to related circuits in the power supply circuit, thereby providing effective overcurrent protection for the load device.

Description

Technical Field

[0001] This application relates to the field of battery protection technology, and in particular to an overcurrent protection circuit, a load power supply circuit, and a vehicle. Background Technology

[0002] Currently, the power supply circuit of low-voltage batteries lacks corresponding overcurrent protection circuits. During the use of low-voltage batteries, if poor grounding occurs, a large current will flow to the low-voltage battery, causing damage to the low-voltage battery circuit. Utility Model Content

[0003] This application provides an overcurrent protection circuit, a load power supply circuit, and a vehicle to solve the above-mentioned technical problems.

[0004] In a first aspect, embodiments of this application provide an overcurrent protection circuit, including:

[0005] A switching module, wherein the switching module is connected in series in the power supply circuit, and the switching module is configured to turn on the power supply circuit or to turn off the power supply circuit based on a turn-off signal;

[0006] A signal amplification module, the input terminal of which is connected to the power supply circuit, is used to amplify the voltage of the power supply circuit to obtain a voltage amplified signal;

[0007] A comparison output module is provided, wherein the input terminal of the comparison output module is connected to the output terminal of the signal amplification module, and the output terminal of the comparison output module is connected to the switch module. The comparison output module is configured to receive the voltage amplification signal and output the shutdown signal to the switch module when the voltage amplification signal is greater than or equal to a preset threshold voltage of the power supply circuit.

[0008] In conjunction with the first aspect, the comparison output module includes a voltage comparator and a first resistor, wherein the voltage comparator includes a positive comparison input terminal, an inverting comparison input terminal, a first signal output terminal, a first positive power supply terminal, and a first negative power supply terminal;

[0009] The positive comparison input terminal is connected to the threshold voltage terminal, the negative comparison input terminal is connected to the output terminal of the signal amplification module, and the threshold voltage terminal is configured to provide the threshold voltage.

[0010] The first positive power supply terminal is connected to a preset power supply, the first negative power supply terminal is grounded, the first signal output terminal is connected to the switch module and connected to the preset power supply through the first resistor, and the first signal output terminal is configured to output the turn-off signal to the switch module when the voltage amplification signal received at the inverting comparison input terminal is greater than or equal to the threshold voltage.

[0011] In conjunction with the first aspect, the signal amplification module includes an amplifier and a current-limiting resistor, and the amplifier includes a non-inverting amplification input terminal, an inverting amplification input terminal, a second signal output terminal, a second positive power supply terminal, and a second negative power supply terminal;

[0012] The non-inverting amplifier input terminal is connected to the switching module, the inverting amplifier input terminal is connected to the second signal output terminal and grounded, the second signal output terminal is connected to the comparator output module, the second positive power supply terminal is connected to the preset power supply, the second negative power supply terminal is grounded, and the current limiting resistor is connected to the second signal output terminal.

[0013] In conjunction with the first aspect, the signal amplification module further includes a bias resistor, a first limiting resistor, a second limiting resistor, and a third limiting resistor; one end of the bias resistor is connected to the non-inverting amplification input terminal, and the other end is connected to a bias voltage terminal, the bias voltage terminal being configured to provide a bias voltage; the first limiting resistor is connected to the non-inverting amplification input terminal; the second limiting resistor is connected between the inverting amplification input terminal and the second signal output terminal; and the third limiting resistor is connected to the inverting amplification input terminal.

[0014] In conjunction with the first aspect, the switch module includes a signal receiving module, a first switch module, and a second switch module; the signal receiving module includes a signal input terminal, a signal connection terminal, and a signal output terminal; the first switch module includes a first switch input terminal, a first switch connection terminal, and a first switch output terminal; the second switch module includes a second switch input terminal, a second switch connection terminal, and a second switch output terminal.

[0015] The signal input terminal is connected to the comparison output module, the signal connection terminal is connected to the first switch connection terminal, the signal output terminal is grounded, the first switch input terminal is connected to the power supply circuit, the first switch output terminal is connected to the second switch connection terminal, the second switch input terminal is connected to the power supply circuit, and the second switch output terminal is connected to the signal amplification module and grounded respectively.

[0016] In conjunction with the first aspect, the signal receiving module includes a drain resistor, a first gate resistor, a first filter resistor, and a first filter capacitor; the drain resistor is connected to the signal connection terminal; the first gate resistor is connected to the signal input terminal; the first filter resistor and the first filter capacitor are connected in parallel between the signal input terminal and the signal output terminal.

[0017] In conjunction with the first aspect, the first switching module includes a first Zener diode, a second filter resistor, and a second filter capacitor. The first Zener diode, the second filter resistor, and the second filter capacitor are connected in parallel between the first switch connection terminal and the first switch input terminal.

[0018] In conjunction with the first aspect, the second switching module includes a third gate resistor, a second Zener diode, a third filter resistor, and a third filter capacitor. The third gate resistor is connected between the second switch connection terminal and the first switch output terminal. The second Zener diode, the third filter resistor, and the third filter capacitor are connected in parallel between the second switch connection terminal and the second switch output terminal.

[0019] In conjunction with the first aspect, the signal receiving module includes a first switching transistor, the first switching module includes a second switching transistor, and the second switching module includes a third switching transistor; the first switching transistor, the second switching transistor, and the third switching transistor include any one or more of MOSFETs or IGBTs.

[0020] In conjunction with the first aspect, it also includes a voltage source module, which includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected to a preset power supply, and the other end is connected to one end of the second voltage divider resistor. The other end of the second voltage divider resistor is grounded. The midpoint between the first voltage divider resistor and the second voltage divider resistor is connected to a threshold voltage terminal, and the voltage at the midpoint between the first voltage divider resistor and the second voltage divider resistor is configured as the threshold voltage.

[0021] Secondly, embodiments of this application provide a load power supply circuit, including a load device and an overcurrent protection circuit as described in any one of the first aspects, wherein the load device is connected to the overcurrent protection circuit.

[0022] Thirdly, embodiments of this application provide a vehicle including a power supply control device and a load power supply circuit as described in the second aspect, wherein the power supply control device is connected to the load power supply circuit.

[0023] One of the above technical solutions has the following advantages or beneficial effects:

[0024] This application provides an overcurrent protection circuit, including: a switching module connected in series in a power supply circuit, configured to turn on the power supply circuit or disconnect the power supply circuit based on a turn-off signal; a signal amplification module, whose input terminal is connected in the power supply circuit, used to amplify the voltage of the power supply circuit to obtain a voltage amplified signal; and a comparison output module, whose input terminal is connected to the output terminal of the signal amplification module, and whose output terminal is connected to the switching module, configured to receive the voltage amplified signal and output a turn-off signal to the switching module when the voltage amplified signal is greater than or equal to a preset threshold voltage of the power supply circuit. The overcurrent protection circuit provided in this application can disconnect the load device in the power supply circuit when a grounding failure occurs during the use of the power supply circuit, preventing large current from flowing to the load device and avoiding damage to related circuits in the power supply circuit, thereby providing effective overcurrent protection for the load device. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of 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.

[0026] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0027] Figure 1 This is a schematic diagram of the overall module connection of the overcurrent protection circuit provided in the embodiments of this application;

[0028] Figure 2 A schematic diagram of the module connection of the overcurrent protection circuit provided in the embodiments of this application;

[0029] Figure 3 A schematic diagram of the specific circuit of the overcurrent protection circuit provided in the embodiments of this application;

[0030] Figure 4 A schematic diagram of the module connection of the load power supply circuit provided in the embodiments of this application;

[0031] Figure 5 This is a schematic diagram of the module connections of a vehicle provided in an embodiment of this application.

[0032] Explanation of reference numerals in the attached figures:

[0033] 100 - Switch module; 110 - First switch module; 120 - Second switch module; 130 - Signal receiving module; 200 - Comparison output module; 300 - Signal amplification module; 400 - Voltage source module. Detailed Implementation

[0034] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0035] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] In the embodiments of this application, "at least one" refers to one or more; "multiple" refers to two or more. In the description of this application, the terms "first," "second," "third," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance, nor should they be construed as indicating or implying order.

[0037] References such as “one embodiment” or “some embodiments” as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the terms “comprising,” “including,” “having,” and variations thereof, as used in this specification, mean “including, but not limited to,” unless otherwise specifically emphasized.

[0038] It should be noted that in the embodiments of this application, "and / or" describes the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects before and after it are in an "or" relationship.

[0039] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0040] The specific implementation methods of this application are illustrated below through examples:

[0041] like Figure 1 As shown in the figure, this application embodiment provides an overcurrent protection circuit for overcurrent protection of a load device in a power supply circuit, including: a switching module 100 connected in series in the power supply circuit, configured to turn on the power supply circuit or turn off the power supply circuit based on a turn-off signal; a signal amplification module 300, whose input terminal is connected in the power supply circuit, used to amplify the voltage of the power supply circuit to obtain a voltage amplified signal; and a comparison output module 200, whose input terminal is connected to the output terminal of the signal amplification module 300, and whose output terminal is connected to the switching module 100, configured to receive the voltage amplified signal, and output a turn-off signal to the switching module 100 when the voltage amplified signal is greater than or equal to a preset threshold voltage of the power supply circuit, the turn-off signal being used to turn off the switching module 100 to provide overcurrent protection for the load device.

[0042] Specifically, the load device includes any of the following: battery, battery pack, battery module, low-voltage battery, indicator light, vehicle air conditioner, and battery box, all capable of storing electrical energy. This embodiment uses a low-voltage battery as an example. The switch module 100 is connected to the positive and negative terminals of the low-voltage battery. Electrical energy flows from the positive terminal, passes through the switch module 100, and finally returns to the negative terminal. Normally, the circuit connecting the switch module 100 and the negative terminal is grounded. When grounding fails, if the low-voltage battery remains connected, other circuits cannot be grounded, and all current will converge at the negative terminal of the low-voltage battery, causing damage to the low-voltage battery and components in the circuit. By setting a signal amplification module 300 at the grounding point of the switch module 100, the current signal flowing through the switch module 100 is amplified (i.e., the amplified signal). The amplified signal is input to the comparison output module 200, which compares the voltage of the amplified signal with a threshold voltage Vref. When the voltage of the amplified signal is less than the threshold voltage Vref, it indicates that the current flowing through the negative terminal of the low-voltage battery is within the range that the low-voltage battery can withstand. Under this current, the low-voltage battery can operate safely. Therefore, the comparator output module 200 sends a conduction signal to the switch module 100. Upon receiving the conduction signal, the switch module 100 maintains the connection between the low-voltage battery and the circuit. When the voltage of the amplified signal is greater than or equal to the threshold voltage Vref, it indicates that the current flowing through the negative terminal of the low-voltage battery exceeds the range that the low-voltage battery can withstand. Therefore, the comparator output module 200 sends a shutdown signal to the switch module 100. Upon receiving the shutdown signal, the switch module 100 disconnects the circuit at the negative terminal of the low-voltage battery, thereby providing overcurrent protection for the low-voltage battery.

[0043] It is understandable that by setting a signal amplification module 300 and a comparison output module 200 at the negative terminal of the low-voltage battery respectively, the monitoring of the negative terminal of the low-voltage battery is realized. Thus, when the negative terminal of the low-voltage battery fails to ground and the current exceeds the safe range, the comparison output module 200 can control the switch module 100 connected to the low-voltage battery to disconnect, thereby realizing the overcurrent protection of the low-voltage battery.

[0044] like Figure 2 and Figure 3As shown in the embodiment of this application, the comparison output module 200 includes a voltage comparator U2 and a first resistor R1. The voltage comparator U2 includes a positive comparison input terminal, an inverting comparison input terminal, a first signal output terminal, a first positive power supply terminal, and a first negative power supply terminal. The positive comparison input terminal is connected to the threshold voltage terminal, and the inverting comparison input terminal is connected to the output terminal of the signal amplification module. The threshold voltage terminal is configured to provide a threshold voltage. The first positive power supply terminal is connected to a preset power supply VCC, the first negative power supply terminal is grounded, the first signal output terminal is connected to the switching module, and is connected to the preset power supply VCC through the first resistor. The first signal output terminal is configured to output a turn-off signal to the switching module when the voltage amplification signal received at the inverting comparison input terminal is greater than or equal to the threshold voltage.

[0045] Specifically, the positive comparison input terminal of voltage comparator U2 is connected to receive the amplified signal; the inverting comparison input terminal is used to receive the threshold voltage Vref; the first positive power supply terminal is used to receive the preset power supply VCC to provide power to the comparator circuit; the first negative power supply terminal is grounded to form a loop in the comparator circuit; the first signal output terminal is used to output a high-level or low-level turn-off signal when the amplified signal is greater than or equal to the threshold voltage Vref, usually the turn-off signal is a low-level signal; and when the amplified signal is less than the threshold voltage Vref, it can output a high-level or low-level turn-on signal, usually the turn-on signal is a high-level signal. It can be assumed that the level of the turn-off signal and the turn-on signal depends on the characteristics of the switching module 100. When the switching module 100 requires a high level to turn on and a low level to turn off, the turn-on signal is high and the turn-off signal is low; conversely, the turn-on signal is low and the turn-off signal is high.

[0046] It is worth noting that the first signal output terminal is connected to a first resistor, and the other end of the first resistor is connected to a preset power supply VCC. When the voltage comparator U2 needs to output a high-level conduction signal, the voltage of the conduction signal is pulled up through the first resistor, so that when the first signal output terminal of the voltage comparator U2 outputs a high level, a current path can be formed, making the voltage of the conduction signal close to the preset power supply VCC.

[0047] Understandably, by setting the voltage comparator U2 and the first resistor, the overcurrent protection circuit can output a corresponding high-level turn-on signal or a low-level turn-off signal according to the overcurrent condition of the switching module 100, thereby realizing the control of normal output or overcurrent protection of the low-voltage battery.

[0048] like Figure 2 and Figure 3As shown in the embodiment of this application, the signal amplification module 300 includes an amplifier U1 and a current-limiting resistor R14. The amplifier U1 includes a non-inverting amplification input terminal, an inverting amplification input terminal, a second signal output terminal, a second positive power supply terminal, and a second negative power supply terminal. The non-inverting amplification input terminal is connected to the first amplification input terminal, the inverting amplification input terminal is connected to the second amplification input terminal and ground, the second signal output terminal is connected to the negative comparison input terminal of the comparison output module 200, the second positive power supply terminal is connected to the preset power supply VCC, the second negative power supply terminal is grounded, and the current-limiting resistor R14 is connected to the second signal output terminal.

[0049] Specifically, the non-inverting input terminal of amplifier U1 is connected to the first amplification input terminal to receive the current signal flowing through the switching module 100; the inverting input terminal is grounded to provide a stable reference point for the non-inverting input terminal, thereby reducing the influence of power supply noise or environmental interference on the current signal; simultaneously, connecting the inverting input terminal to the second amplification input terminal ensures that the output signal completely follows the signal at the non-inverting input terminal, thus achieving signal isolation or impedance matching; the second positive power supply is connected to the preset power supply VCC to limit the upper limit amplitude of the amplified signal; the second negative power supply is grounded to limit the lower limit amplitude of the amplified signal. Setting the current-limiting resistor R14 at the second signal output terminal of amplifier U1 can limit the peak current of the output amplified signal, thereby preventing damage to the internal components of amplifier U1, and also suppressing oscillations to avoid phase delay superposition caused by high-frequency signals.

[0050] It is worth noting that the signal amplification module 300 also includes a bias resistor R10, a first limiting resistor R11, a second limiting resistor R12, and a third limiting resistor R13. One end of the bias resistor R10 is connected to the non-inverting amplification input terminal, and the other end is connected to the bias voltage terminal, which is configured to provide a bias voltage V0. The first limiting resistor R11 is connected to the non-inverting amplification input terminal, the second limiting resistor R12 is connected between the inverting amplification input terminal and the second signal output terminal, and the third limiting resistor R13 is connected to the inverting amplification input terminal. The bias voltage V0 is used to prevent the voltage signal at the input of the non-inverting amplification terminal from being too low and can be selected according to the actual situation of the circuit; in some cases, when the voltage signal is large enough, the bias voltage V0 can be 0. The first limiting resistor R11 is used to limit the current signal at the switching module 100, preventing the peak value of the current signal from being too large and causing damage to the internal circuitry of amplifier U1. At the same time, the first limiting resistor R11 can also suppress oscillation and prevent high-frequency signals from impacting the internal circuitry of amplifier U1. The second limiting resistor R12 is used to implement feedback. The second limiting resistor R12 forms a closed-loop negative feedback between the negative phase amplifier input terminal and the second signal output terminal, injecting the output turn-on or turn-off signal into the inverting amplifier input terminal in an inverted manner to precisely control the gain of the amplifier circuit. At the same time, the second limiting resistor R12 can also force the output turn-on or turn-off signal to be linearly related to the input current signal, thereby reducing harmonic distortion caused by the nonlinear characteristics of amplifier U1. The inverting amplifier input terminal is grounded through the third limiting resistor R13 to form a stable reference potential, thereby eliminating the interference of common-mode voltage in the circuit.

[0051] It is conceivable that the signal amplification module 300 provided in this application embodiment may include a differential bias amplifier circuit constructed from a differential amplifier U1, or an operational amplifier circuit constructed from an operational amplifier U1. The specific amplifier circuit used can be selected based on the overcurrent protection circuit; this application embodiment will not provide further examples here.

[0052] It is understandable that by setting amplifier U1 and multiple resistors connected to amplifier U1 in the overcurrent protection circuit, the current signal flowing through the switching module 100 is amplified, which facilitates the comparison output module 200 to compare the amplified signal with the threshold voltage Vref, thereby improving the output efficiency.

[0053] like Figure 2 As shown in the embodiment of this application, the switch module 100 includes a signal receiving module 130, a first switch module 110 and a second switch module 120. The signal receiving module 130 is used to disconnect the first switch module 110 and the second switch module 120 from the low-voltage battery when a shutdown signal is received.

[0054] Specifically, the first switch module 110 and the second switch module 120 are connected to the positive and negative terminals of the low-voltage battery, respectively. The signal receiving module 130 controls the connection state of the first switch module 110; the second switch module 120 can only be turned on when the first switch module 110 is on. When the signal receiving module 130 receives the on signal from the comparison output module 200, the signal receiving module 130 is turned on, and the first switch module 110 and the second switch module 120 are turned on successively, allowing the low-voltage battery to operate normally. When the signal receiving module 130 receives the off signal from the comparison output module 200, the signal receiving module 130 is turned off, and the first switch module 110 and the second switch module 120 are disconnected, preventing the low-voltage battery from outputting power normally, thus achieving overcurrent protection for the low-voltage battery.

[0055] It is understandable that by setting the signal receiving module 130, the first switch module 110 and the second switch module 120 can be turned on successively, thereby preventing the positive and negative terminals of the low-voltage battery from being reversed and causing damage to the devices.

[0056] like Figure 2 and Figure 3 As shown in the embodiment of this application, the signal receiving module 130 includes a signal input terminal, a signal connection terminal, and a signal output terminal; the first switch module 110 includes a first switch input terminal, a first switch connection terminal, and a first switch output terminal; the second switch module 120 includes a second switch input terminal, a second switch connection terminal, and a second switch output terminal; the signal input terminal is connected to the comparison output module, the signal connection terminal is connected to the first switch connection terminal, the signal output terminal is grounded, the first switch input terminal is connected to the first output terminal of the low-voltage battery, the first switch output terminal is connected to the second switch connection terminal, the second switch input terminal is connected to the second output terminal of the low-voltage battery, and the second switch output terminal is connected to the signal amplification module 300 and grounded respectively.

[0057] Specifically, the signal input terminal is connected to the first signal output terminal of the voltage comparator to receive a turn-on signal or a turn-off signal; the signal connection terminal is connected to the first switch connection terminal of the first switch module 110, while the signal output terminal is grounded. When the signal input terminal receives a turn-on signal, the signal connection terminal and the signal output terminal are connected. At this time, the first switch connection terminal is grounded through the signal connection terminal, making the first switch input terminal and the first switch output terminal connected. The first switch input terminal is connected to the low-voltage battery to obtain the current output by the low-voltage battery. The first switch output terminal is connected to the second switch connection terminal. After the second switch connection terminal receives a high-level signal from the low-voltage battery, it makes the second switch input terminal and the second switch output terminal connected. Finally, both the first output terminal and the second output terminal of the low-voltage battery are connected.

[0058] It is understandable that by connecting the signal receiving module 130 to the first switch module 110, the signal receiving module 130 can control the conduction and cutoff of the first switch module 110. By connecting the first switch module 110 to the second switch module 120, the state of the first switch module 110 can control the conduction and cutoff of the second switch module 120. Furthermore, through the series connection of the three, the first switch module 110 and the second switch module 120 are turned on sequentially, thereby ensuring that the circuit cannot start when reverse-connected to a low-voltage battery, thus protecting the components in the circuit.

[0059] like Figure 2 and Figure 3 As shown in the embodiment of this application, the signal receiving module 130 includes a first switch Q1, which includes a first source, a first drain, and a first gate. The first gate is configured as a signal input terminal, the first drain is configured as a signal connection terminal, and the first source is configured as a signal output terminal.

[0060] Specifically, the first switching transistor Q1 includes an N-type MOS transistor. When the first gate receives a high-level turn-on signal, the first source and the first drain are turned on; when the first gate receives a low-level turn-off signal, the first source and the first drain are turned off.

[0061] It is worth noting that the signal receiving module 130 also includes a drain resistor R3, a first gate resistor R8, a first filter resistor R2, and a first filter capacitor C1. The drain resistor R3 is connected to the first drain and is used to limit the current signal input to the first drain to prevent the excessive current signal from impacting the first switching transistor Q1. The first gate resistor R8 is connected to the first gate and is used to limit the current of the on and off signals input to the first gate to prevent the large current of the on or off signals from impacting and damaging the first switching transistor Q1. The first filter resistor R2 and the first filter capacitor C1 are connected in parallel between the first gate and the first source to filter the on and off signals, avoiding high-frequency noise in the on or off signals from interfering with the circuit.

[0062] It is understandable that by setting the first switch Q1, the first gate resistor R8, the first filter resistor R2, and the first filter capacitor C1, the circuit can filter and limit the turn-on and turn-off signals input to the first switch Q1 while ensuring that the first switch Q1 can be turned on and off. This prevents signal interference from turning the first switch Q1 on or off, and improves the stability and reliability of the circuit.

[0063] like Figure 3As shown in the embodiment of this application, the first switch module 110 includes a second switch transistor Q2. The second switch transistor Q2 includes a second source, a second drain, and a second gate. The second source is configured as a first switch input terminal, the second drain is configured as a first switch output terminal, and the second gate is configured as a first switch connection terminal. The second gate is also connected to the second source.

[0064] Specifically, the second switch Q2 includes a P-type MOSFET. When the first drain and the first source are connected, the second gate connected to the first drain is connected to ground. The second gate is equivalent to receiving a low-level signal. At this time, the second source and the second drain are connected. When the first drain and the first source are cut off, the second gate receives a high level from the low-voltage battery. Therefore, the second source and the second drain are cut off.

[0065] It is worth noting that the first switching module 110 also includes a first Zener diode Z1, a second filter resistor R4, and a second filter capacitor C2. The first Zener diode Z1, the second filter resistor R4, and the second filter capacitor C2 are connected in parallel between the second gate and the second source. The first Zener diode Z1 is used for overvoltage protection. By setting the reverse breakdown voltage of the first Zener diode Z1, the gate-source voltage is limited to a safe range. When the drive signal or coupling noise causes the gate-source voltage to exceed the reverse breakdown voltage, the first Zener diode Z1 conducts in reverse, clamping the voltage to prevent breakdown of the gate oxide layer, thus protecting the first switching transistor Q1. The second filter resistor R4 provides a discharge path for the equivalent capacitance of the second gate, ensuring the stability of the second gate potential. Simultaneously, the second filter resistor R4 and the second filter capacitor C2 can also form a low-pass filter to filter out high-frequency interference in the drive signal of the second gate, reducing the probability of false triggering.

[0066] It is understandable that by setting the second switch Q2, the first Zener diode Z1, the second filter resistor R4, and the second filter capacitor C2, the driving signal input to the second switch Q2 can be filtered and current limited while ensuring that the second switch Q2 can be turned on and off. This prevents signal interference from turning the second switch Q2 on or off, thereby improving the stability and reliability of the circuit.

[0067] like Figure 3 As shown in the embodiment of this application, the second switch module 120 includes a third switch transistor Q3, which includes a third source, a third drain, and a third gate. The third source is configured as the second switch output terminal, the third drain is configured as the second switch input terminal, and the third gate is configured as the second switch connection terminal.

[0068] Specifically, the third switch Q3 includes an N-type MOSFET. When the second drain and the second source are turned on, the third gate connected to the second drain receives a high-level current from the low-voltage battery. At this time, the third source and the third drain are turned on. When the second drain and the second source are turned off, there is no signal at the third gate. Therefore, the third source and the third drain are turned off.

[0069] It is worth noting that the second switching module 120 also includes a third gate resistor R6, a second Zener diode Z2, a third filter resistor R5, and a third filter capacitor C3. The third gate resistor R6 is connected between the third gate and the second drain to limit the current signal input to the third gate, so as to prevent the current signal of the low-voltage battery from impacting and damaging the first switching transistor Q1. The second Zener diode Z2, the third filter resistor R5, and the third filter capacitor C3 are connected in parallel between the third gate and the third source. Among them, the second Zener diode Z2 is used for overvoltage protection. By setting the reverse breakdown voltage of the second Zener diode Z2, the gate-source voltage is limited to a safe range. When the gate-source voltage exceeds the reverse breakdown voltage due to current signal or coupling noise, the second Zener diode Z2 conducts in reverse to clamp the voltage and prevent the gate oxide layer from breaking down, thus protecting the third switch Q3. The third filter resistor R5 provides a discharge path for the equivalent capacitance of the third gate, ensuring the potential stability of the third gate. At the same time, the third filter resistor R5 and the third filter capacitor C3 can also form a low-pass filter to filter out high-frequency interference in the drive signal of the third gate and reduce the probability of false triggering.

[0070] It is important to note that the third source electrode is connected to both ground and the non-inverting input of the signal amplification module 300. In the circuit connected to the negative terminal of the low-voltage battery, most of the current forms a loop through the ground at the third source electrode. Therefore, when the ground at the third source electrode fails, the current flows to the signal amplification module 300. Thus, as... Figure 3 As shown, a sampling resistor R9 is set at the third source terminal to limit the current in the circuit containing the third source terminal. By inputting the current flowing through the sampling resistor R9 or the voltage across the sampling resistor R9 to the non-inverting amplification input of amplifier U1, the current signal flowing through the third source terminal is amplified and output to the comparison output module 200, thereby realizing the monitoring of the grounding at the third source terminal, i.e., the negative terminal of the low-voltage battery.

[0071] It is understandable that by setting the third switch Q3, the second Zener diode Z2, the third filter resistor R5, and the third filter capacitor C3, the driving signal input to the third switch Q3 can be filtered and current-limited while ensuring that the third switch Q3 can be turned on and off. This prevents signal interference from turning the third switch Q3 on or off, thus improving the stability and reliability of the circuit. At the same time, the sampling resistor R9 is set to monitor the grounding of the negative terminal of the low-voltage battery, avoiding excessive current accumulation at the negative terminal due to grounding failure, which could damage the low-voltage battery and other components.

[0072] like Figure 3 As shown, in this embodiment of the application, a voltage source module 400 is also included. The voltage source module 400 includes a first voltage divider resistor R15 and a second voltage divider resistor R7. One end of the first voltage divider resistor R15 is connected to a preset power supply VCC, and the other end is connected to one end of the second voltage divider resistor R7. The other end of the second voltage divider resistor R7 is grounded. The midpoint of the first voltage divider resistor R15 and the second voltage divider resistor R7 is connected to a threshold voltage terminal. The voltage at the midpoint of the first voltage divider resistor R15 and the second voltage divider resistor R7 is configured as the threshold voltage Vref.

[0073] Specifically, the first voltage divider resistor R15 and the second voltage divider resistor R7 are connected in series, and the preset power supply VCC is applied across both the first voltage divider resistor R15 and the second voltage divider resistor R7. The midpoint voltage between the first voltage divider resistor R15 and the second voltage divider resistor R7 can be controlled by adjusting their ratio. Therefore, based on the circuit structure of the low-voltage battery and the voltage range that the low-voltage battery can withstand, the threshold voltage Vref and the value of the preset power supply are determined, and the resistance values ​​of the first voltage divider resistor R15 and the second voltage divider resistor R7 are set accordingly.

[0074] Understandably, by changing the resistance ratio of the first voltage divider resistor R15 and the second voltage divider resistor R7 through the voltage source module 400, the value of the threshold voltage Vref can be flexibly adjusted to achieve the required output threshold voltage Vref. The threshold voltage Vref is then input to the comparison output module 200 for comparison with the amplified signal, enabling the comparison output module 200 to control the on / off state of the switching module 100, thereby achieving overcurrent protection for the low-voltage battery.

[0075] In summary, by setting a first switch module 110 and a second switch module 120 at the positive and negative terminals of the low-voltage battery, and controlling the first switch module 110 and the second switch module 120 to turn on and off sequentially via a signal receiving module 130, the circuit can be started when connected to the low-voltage battery in the correct direction, but cannot be started when connected in the reverse direction, thus protecting the components in the circuit. Furthermore, by using a signal amplification module 300 and a comparison output module 200, the negative terminal of the low-voltage battery is monitored. Therefore, when the negative terminal of the low-voltage battery fails to ground and the current exceeds the safe range, the comparison output module 200 can control the switch module 100 connected to the low-voltage battery to disconnect, thereby achieving overcurrent protection for the low-voltage battery.

[0076] like Figure 4 As shown in the embodiments of this application, a load power supply circuit is also provided, including a load device and an overcurrent protection circuit as provided in any of the above embodiments, wherein the load device is connected to the overcurrent protection circuit.

[0077] like Figure 5 As shown in the embodiments of this application, a vehicle is also provided, including a power supply control device and a load power supply circuit as provided in the above embodiments, wherein the power supply control device is connected to the load power supply circuit.

[0078] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An overcurrent protection circuit, characterized in that, include: A switching module, wherein the switching module is connected in series in the power supply circuit, and the switching module is configured to turn on the power supply circuit or to turn off the power supply circuit based on a turn-off signal; A signal amplification module, the input terminal of which is connected to the power supply circuit, is used to amplify the voltage of the power supply circuit to obtain a voltage amplified signal; A comparison output module is provided, wherein the input terminal of the comparison output module is connected to the output terminal of the signal amplification module, and the output terminal of the comparison output module is connected to the switch module. The comparison output module is configured to receive the voltage amplification signal and output the shutdown signal to the switch module when the voltage amplification signal is greater than or equal to a preset threshold voltage of the power supply circuit.

2. The overcurrent protection circuit of claim 1, wherein, The comparison output module includes a voltage comparator and a first resistor. The voltage comparator includes a positive comparison input terminal, an inverting comparison input terminal, a first signal output terminal, a first positive power supply terminal, and a first negative power supply terminal. The positive comparison input terminal is connected to the threshold voltage terminal, the negative comparison input terminal is connected to the output terminal of the signal amplification module, and the threshold voltage terminal is configured to provide the threshold voltage. The first positive power supply terminal is connected to a preset power supply, the first negative power supply terminal is grounded, the first signal output terminal is connected to the switch module and connected to the preset power supply through the first resistor, and the first signal output terminal is configured to output the turn-off signal to the switch module when the voltage amplification signal received at the inverting comparison input terminal is greater than or equal to the threshold voltage.

3. The overcurrent protection circuit according to claim 1, characterized in that, The signal amplification module includes an amplifier and a current-limiting resistor. The amplifier includes a non-inverting amplification input terminal, an inverting amplification input terminal, a second signal output terminal, a second positive power supply terminal, and a second negative power supply terminal. The non-inverting amplifier input terminal is connected to the switching module, the inverting amplifier input terminal is connected to the second signal output terminal and grounded, the second signal output terminal is connected to the comparator output module, the second positive power supply terminal is connected to the preset power supply, the second negative power supply terminal is grounded, and the current limiting resistor is connected to the second signal output terminal.

4. The overcurrent protection circuit of claim 3, wherein, The signal amplification module further includes a bias resistor, a first limiting resistor, a second limiting resistor, and a third limiting resistor; one end of the bias resistor is connected to the non-inverting amplification input terminal, and the other end is connected to a bias voltage terminal, the bias voltage terminal being configured to provide a bias voltage; the first limiting resistor is connected to the non-inverting amplification input terminal; the second limiting resistor is connected between the inverting amplification input terminal and the second signal output terminal; and the third limiting resistor is connected to the inverting amplification input terminal.

5. The overcurrent protection circuit of claim 1, wherein, The switch module includes a signal receiving module, a first switch module, and a second switch module; the signal receiving module includes a signal input terminal, a signal connection terminal, and a signal output terminal; the first switch module includes a first switch input terminal, a first switch connection terminal, and a first switch output terminal; the second switch module includes a second switch input terminal, a second switch connection terminal, and a second switch output terminal. The signal input terminal is connected to the comparison output module, the signal connection terminal is connected to the first switch connection terminal, the signal output terminal is grounded, the first switch input terminal is connected to the positive terminal of the power supply circuit, the first switch output terminal is connected to the second switch connection terminal, the second switch input terminal is connected to the negative terminal of the power supply circuit, and the second switch output terminal is connected to the signal amplification module and grounded respectively.

6. The overcurrent protection circuit of claim 5, wherein, The signal receiving module includes a drain resistor, a first gate resistor, a first filter resistor, and a first filter capacitor; the drain resistor is connected to the signal connection terminal; the first gate resistor is connected to the signal input terminal; the first filter resistor and the first filter capacitor are connected in parallel between the signal input terminal and the signal output terminal.

7. The overcurrent protection circuit of claim 5, wherein, The first switching module includes a first Zener diode, a second filter resistor, and a second filter capacitor. The first Zener diode, the second filter resistor, and the second filter capacitor are connected in parallel between the first switch connection terminal and the first switch input terminal.

8. The overcurrent protection circuit of claim 5, wherein, The second switching module includes a third gate resistor, a second Zener diode, a third filter resistor, and a third filter capacitor. The third gate resistor is connected between the second switch connection terminal and the first switch output terminal. The second Zener diode, the third filter resistor, and the third filter capacitor are connected in parallel between the second switch connection terminal and the second switch output terminal.

9. The overcurrent protection circuit of claim 5, wherein, The signal receiving module includes a first switching transistor, the first switching module includes a second switching transistor, and the second switching module includes a third switching transistor; the first switching transistor, the second switching transistor, and the third switching transistor include any one or more of MOSFETs or IGBTs.

10. The overcurrent protection circuit according to claim 1, characterized in that, It also includes a voltage source module, which includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected to a preset power supply, and the other end is connected to one end of the second voltage divider resistor. The other end of the second voltage divider resistor is grounded. The midpoint between the first voltage divider resistor and the second voltage divider resistor is connected to a threshold voltage terminal. The voltage at the midpoint between the first voltage divider resistor and the second voltage divider resistor is configured as the threshold voltage.

11. A load power supply circuit, characterized in that, It includes a load device and an overcurrent protection circuit as described in any one of claims 1-10, wherein the load device is connected to the overcurrent protection circuit.

12. A vehicle comprising a power supply control device and a load power supply circuit as claimed in claim 11, wherein the power supply control device is connected to the load power supply circuit.

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