Reverse connection prevention circuit and electronic equipment

Abstract

The utility model provides an anti-reverse connection circuit and electronic equipment, and relates to the technical field of circuit protection. In the reverse connection prevention circuit, a first end of a first switch module is electrically connected with a first electrode of a first power supply, and a second end of the first switch module is electrically connected with a load; the first end of the second switch module is electrically connected with the first electrode of the first power supply, the second end of the second switch module is electrically connected with the control end of the first switch module, and the control end of the second switch module is electrically connected with the first driving module; the second power supply is electrically connected with the first driving module. Under the condition that the voltage of the first electrode of the first power supply is not higher than a first threshold (the first threshold is higher than ground voltage), the second power supply drives the second switch module to be conducted through the first driving module, so that the first switch module is turned off, and the first switch module is turned off in advance under the condition that the positive and negative polarities of the first power supply are not completely turned. And the damage to components caused by reverse current is effectively avoided.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, and more specifically, to a reverse connection protection circuit and electronic equipment. Background Technology

[0002] In electronic circuits, when the power supply is reversed (e.g., the positive terminal is disconnected, grounded, or a negative pulse is generated), the current will flow in the opposite direction. This reverse current may damage the components in the circuit, so it is necessary to add a reverse connection protection circuit.

[0003] Existing reverse connection protection circuits require the power supply polarity to be completely reversed before the reverse connection protection function takes effect. However, when the power supply is reversed, it usually takes a certain amount of time for the polarity to be completely reversed, which means that the reverse connection protection circuit cannot perform its protection function in time, resulting in damage to components. Utility Model Content

[0004] The purpose of this invention is to provide a reverse connection protection circuit and electronic device to solve the problem that existing reverse connection protection circuits cannot provide timely reverse connection protection when the power supply is reversed.

[0005] The embodiments of this utility model can be implemented as follows:

[0006] In a first aspect, this utility model provides a reverse connection protection circuit, which includes a first power supply, a first switch module, a second switch module, a first drive module, and a second power supply. A first terminal of the first switch module is electrically connected to a first electrode of the first power supply, and a second terminal of the first switch module is electrically connected to a load. A first terminal of the second switch module is electrically connected to the first electrode of the first power supply, and a second terminal of the second switch module is electrically connected to a control terminal of the first switch module. The control terminal of the second switch module is electrically connected to the first drive module. The second power supply is electrically connected to the first drive module.

[0007] The second power supply is used to drive the second switching module to turn on, thereby turning off the first switching module, when the voltage of the first electrode of the first power supply is not higher than a first threshold; the first threshold is higher than the ground voltage.

[0008] In an optional implementation, the first driving module includes a voltage divider unit and a first diode. The cathode of the first diode is electrically connected to the control terminal of the second switching module, and the anode of the first diode is electrically connected to the voltage divider unit. The voltage divider unit is also electrically connected to the second power supply.

[0009] In an optional embodiment, the voltage divider unit includes a first resistor and a second resistor. One end of the first resistor is electrically connected to the anode of the first diode, and the other end of the first resistor is electrically connected to the second power supply. One end of the second resistor is electrically connected between the anode of the first diode and the first resistor, and the other end of the second resistor is grounded.

[0010] In an optional implementation, the first threshold is VCC*r2 / (r1+r2)-0.7, where VCC represents the voltage value provided by the second power supply, r1 represents the resistance value of the first resistor, and r2 represents the resistance value of the second resistor.

[0011] In an optional embodiment, the first switching module includes an NMOS transistor and a third resistor. The source of the NMOS transistor is electrically connected to the first electrode of the first power supply, the gate of the NMOS transistor is electrically connected to the second terminal of the second switching module, and the drain of the NMOS transistor is electrically connected to the load. The third resistor is electrically connected between the source and the gate of the NMOS transistor.

[0012] In an optional embodiment, the first switching module further includes a Zener diode, the anode of which is electrically connected to the source of the NMOS transistor, and the cathode of which is electrically connected to the gate of the NMOS transistor.

[0013] In an optional embodiment, the second switching module includes a transistor and a fourth resistor. The base of the transistor is electrically connected to the first driving module, the collector of the transistor is electrically connected to the control terminal of the first switching module, and the emitter of the transistor is electrically connected to the first electrode of the first power supply. The fourth resistor is electrically connected between the base and emitter of the transistor.

[0014] In an optional embodiment, the reverse connection protection circuit further includes a second drive module, one end of which is electrically connected to the control terminal of the second switch module, and the other end of which is grounded.

[0015] The second driving module is used to turn on the second switching module and turn off the first switching module when the voltage of the first electrode of the first power supply is not higher than the second threshold; the second threshold is lower than the ground voltage.

[0016] In an optional implementation, the second driving module includes a second diode and a fifth resistor. The cathode of the second diode is electrically connected to the control terminal of the second switching module, the anode of the second diode is electrically connected to one end of the fifth resistor, and the other end of the fifth resistor is grounded.

[0017] Secondly, this utility model provides an electronic device, including the reverse connection protection circuit described in any of the foregoing embodiments.

[0018] The beneficial effects of the reverse connection protection circuit and electronic device provided by this utility model embodiment include: the reverse connection protection circuit includes a first power supply, a first switch module, a second switch module, a first drive module, and a second power supply. The first terminal of the first switch module is electrically connected to the first electrode of the first power supply, and the second terminal of the first switch module is electrically connected to the load. The first terminal of the second switch module is electrically connected to the first electrode of the first power supply, the second terminal of the second switch module is electrically connected to the control terminal of the first switch module, and the control terminal of the second switch module is electrically connected to the first drive module. The second power supply is electrically connected to the first drive module. When the voltage of the first electrode of the first power supply is not higher than a first threshold (the first threshold is higher than the ground voltage), the second power supply drives the second switch module to conduct through the first drive module, thereby turning off the first switch module. This achieves the early shutdown of the first switch module before the positive and negative polarities of the first power supply are completely reversed, effectively avoiding damage to components caused by reverse current and solving the problem of insufficient timely reverse connection protection in the prior art. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a structural block diagram of the reverse connection protection circuit provided in this embodiment;

[0021] Figure 2 This is a schematic diagram of a circuit structure for the reverse connection protection circuit provided in this embodiment;

[0022] Figure 3 A schematic diagram of voltage changes for providing reverse connection protection to an existing reverse connection protection circuit;

[0023] Figure 4 A schematic diagram of voltage changes for reverse connection protection provided by the reverse connection protection circuit in this embodiment;

[0024] Figure 5 This is another structural block diagram of the reverse connection protection circuit provided in this embodiment;

[0025] Figure 6 This is a schematic diagram of another circuit structure for the reverse connection protection circuit provided in this embodiment.

[0026] Icons: 100 - Reverse connection protection circuit; 200 - Load; 110 - First power supply; 120 - First switching module; 130 - Second switching module; 140 - First drive module; 150 - Second power supply; 160 - Second drive module; 141 - Voltage divider unit; R1 - First resistor; R2 - Second resistor; R3 - Third resistor; R4 - Fourth resistor; R5 - Fifth resistor; D1 - First diode; D2 - Second diode; D3 - Zener diode; Q1 - NMOS transistor; Q2 - Transistor. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] Furthermore, the terms "first," "second," and "third" are used only for distinguishing descriptions and should not be interpreted as indicating or implying relative importance.

[0032] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.

[0033] Existing reverse connection protection circuits require the power supply polarity to be completely reversed before they can provide protection. This means that the reverse connection protection is not timely enough and cannot effectively prevent reverse current from damaging components.

[0034] Based on this, the present invention provides a reverse connection protection circuit and electronic equipment, which can shut down the first switch module in advance before the positive and negative polarities of the first power supply are completely reversed, effectively avoiding damage to components by reverse current and solving the problem of insufficient timeliness of reverse connection protection in the prior art.

[0035] The following describes in detail the circuit structure, working principle, and technical effects of the reverse connection protection circuit provided by this utility model through embodiments and in conjunction with the accompanying drawings.

[0036] The reverse connection protection circuit provided by this utility model can be applied to automotive ECUs (Electronic Control Units), SCUs (System Control Units), vehicle sensors, vehicle chargers, and other devices that require reverse connection protection.

[0037] Please refer to Figure 1 The reverse connection protection circuit 100 includes a first power supply 110, a first switch module 120, a second switch module 130, a first drive module 140, and a second power supply 150. The first terminal of the first switch module 120 is electrically connected to the first electrode of the first power supply 110, and the second terminal of the first switch module 120 is electrically connected to the load 200. The first terminal of the second switch module 130 is electrically connected to the first electrode of the first power supply 110, the second terminal of the second switch module 130 is electrically connected to the control terminal of the first switch module 120, and the control terminal of the second switch module 130 is electrically connected to the first drive module 140. The second power supply 150 is electrically connected to the first drive module 140.

[0038] The second power supply 150 is used to drive the second switch module 130 to conduct through the first drive module 140 when the voltage of the first electrode of the first power supply 110 is not higher than the first threshold, thereby turning off the first switch module 120; the first threshold is higher than the ground voltage.

[0039] The first power supply 110 typically includes two electrodes, referred to in this embodiment as the first electrode and the second electrode. It is understood that when the two electrodes of the first power supply 110 are correctly connected, the first electrode is positive and the second electrode is negative; when the first power supply 110 is reversed, the polarities of the first and second electrodes will be reversed.

[0040] In this embodiment, the first power supply 110 can be understood as an external power supply (such as a car's onboard battery), and the second power supply 150 can be understood as an internal power supply (such as a power module inside a car's electronic system). When the first power supply 110 is reversed, the second power supply 150 supplies power to the system, and is not affected by the reverse connection of the first power supply 110.

[0041] In this embodiment, the ground voltage can be set according to the actual scenario. For example, in a car, the car body can be used as ground to provide a unified reference voltage for the entire automotive electronic system. The ground voltage can be understood as the voltage of the car body ground, and its value can be 0V, ±0.1V, ±0.5V, etc. This embodiment does not limit this value.

[0042] In this embodiment, when the first power supply 110 is reverse-connected, the voltage of the first electrode of the first power supply 110 will begin to drop. Since the first threshold is higher than the ground voltage, when the voltage of the first electrode of the first power supply 110 is equal to or lower than the first threshold, although the positive and negative polarities of the first power supply 110 have not been completely reversed, the second power supply 150 can provide driving current to the second switch module 130 through the first drive module 140, thereby driving the second switch module 130 to conduct. After the second switch module 130 is conducted, the first switch module 120 will be turned off, and the current will be reversed and cut off. This achieves the early shutdown of the first switch module 120 before the positive and negative polarities of the first power supply 110 have been completely reversed, thereby better protecting the internal components of the system.

[0043] As can be seen, the reverse connection protection circuit provided by this utility model includes a first power supply, a first switch module, a second switch module, a first drive module, and a second power supply. The first terminal of the first switch module is electrically connected to the first electrode of the first power supply, and the second terminal of the first switch module is electrically connected to the load. The first terminal of the second switch module is electrically connected to the first electrode of the first power supply, and the second terminal of the second switch module is electrically connected to the control terminal of the first switch module. The control terminal of the second switch module is electrically connected to the first drive module. The second power supply is electrically connected to the first drive module. When the voltage at the first electrode of the first power supply is not higher than a first threshold, the second power supply drives the second switch module to conduct through the first drive module, thereby turning off the first switch module. This achieves early shutdown of the first switch module before the polarity of the first power supply is completely reversed, effectively preventing damage to components from reverse current and solving the problem of insufficient timely reverse connection protection in the prior art.

[0044] In some implementation methods, please refer to Figure 2The first driving module 140 may include a voltage divider unit 141 and a first diode D1. The cathode of the first diode D1 is electrically connected to the control terminal of the second switching module 130, and the anode of the first diode D1 is electrically connected to the voltage divider unit 141. The voltage divider unit 141 is also electrically connected to the second power supply 150.

[0045] The voltage divider unit 141 includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 is electrically connected to the anode of the first diode D1, and the other end of the first resistor R1 is electrically connected to the second power supply 150. One end of the second resistor R2 is electrically connected between the anode of the first diode D1 and the first resistor R1, and the other end of the second resistor R2 is grounded.

[0046] In this embodiment, the first diode D1 ensures that current can only flow from the second power supply 150 to the control terminal of the second switching module 130, without flowing in the opposite direction, thus providing isolation and protection and improving circuit reliability. The first resistor R1 and the second resistor R2 together form a voltage divider unit 141, which determines the threshold voltage at which the second switching module 130 is turned on.

[0047] For example, based on Figure 2 As can be seen from the connection relationship, the first threshold can be VCC*r2 / (r1+r2)-0.7, where VCC represents the voltage value provided by the second power supply 150, r1 represents the resistance value of the first resistor R1, and r2 represents the resistance value of the second resistor R2.

[0048] That is to say, when the voltage of the first electrode of the first power supply 110 is equal to or lower than (VCC*r2 / (r1+r2)-0.7)V, the second power supply 150 provides driving current to the second switching module 130 through the first resistor R1, the second resistor R2 and the first diode D1. At this time, the second switching module 130 is turned on, the first switching module 120 is turned off, and the current is reversed and cut off.

[0049] In some implementation methods, please continue to refer to Figure 2 The first switching module 120 includes an NMOS transistor Q1 and a third resistor R3. The source of the NMOS transistor Q1 is electrically connected to the first electrode of the first power supply 110, the gate of the NMOS transistor Q1 is electrically connected to the second terminal of the second switching module 130, and the drain of the NMOS transistor Q1 is electrically connected to the load 200. The third resistor R3 is electrically connected between the source and the gate of the NMOS transistor Q1.

[0050] In this embodiment, the third resistor R3 is the bias resistor for the NMOS transistor Q1. By connecting the two ends of the third resistor R3 to the source and gate of the NMOS transistor Q1 respectively, a bias voltage can be provided to the NMOS transistor Q1, so that the NMOS transistor Q1 remains in the conducting state when no reverse power supply occurs. Here, VCP is the control voltage for the gate of the NMOS transistor Q1.

[0051] It is understandable that the gate of NMOS transistor Q1 is the control terminal of the first switching module 120, the source of NMOS transistor Q1 is the first terminal of the first switching module 120, and the drain of NMOS transistor Q1 is the second terminal of the first switching module 120.

[0052] In some embodiments, the first switching module 120 may further include a Zener diode D3, the anode of which is electrically connected to the source of the NMOS transistor Q1, and the cathode of which is electrically connected to the gate of the NMOS transistor Q1.

[0053] In this embodiment, by placing a Zener diode D3 between the source and gate of the NMOS transistor Q1, the gate voltage of the NMOS transistor Q1 can be clamped to prevent the NMOS transistor Q1 from being damaged due to excessive gate voltage.

[0054] In some implementation methods, please continue to refer to Figure 2 The second switch module 130 includes a transistor Q2 and a fourth resistor R4. The base of transistor Q2 is electrically connected to the first drive module 140, the collector of transistor Q2 is electrically connected to the control terminal of the first switch module 120, and the emitter of transistor Q2 is electrically connected to the first electrode of the first power supply 110. The fourth resistor R4 is electrically connected between the base and emitter of transistor Q2.

[0055] In this embodiment, the base of transistor Q2 is the control terminal of the second switching module 130, which is specifically electrically connected to the cathode of the first diode D1 in the first driving module 140. The collector of transistor Q2 is the second terminal of the second switching module 130, which is specifically electrically connected to the gate of NMOS transistor Q1. The emitter of transistor Q2 is the first terminal of the second switching module 130.

[0056] In this embodiment, the fourth resistor R4 is the bias resistor of the transistor Q2. By connecting the two ends of the fourth resistor R4 to the base and emitter of the transistor Q2 respectively, a bias voltage can be provided to the transistor Q2, so that the transistor Q2 remains in the off state when no reverse power supply occurs.

[0057] Under normal system operation, transistor Q2 is off, NMOS transistor Q1 is on, and current flows from the first electrode of the first power supply 110 through NMOS transistor Q1 to the load 200. The first power supply 110 normally supplies power to the load 200. When the first electrode of the first power supply 110 is disconnected, grounded, or a negative pulse is generated, the voltage of the first electrode of the first power supply 110 begins to drop. When the voltage of the first electrode of the first power supply 110 is equal to or lower than (VCC*r2 / (r1+r2)-0.7)V, a current loop is formed between the second power supply 150, the first resistor R1, the first diode D1, the third resistor R3, and the first electrode of the first power supply 110. At this time, the second power supply 150 provides base current to transistor Q2, causing transistor Q2 to conduct and NMOS transistor Q1 to turn off. No reverse current flows through NMOS transistor Q1, effectively preventing reverse current from damaging the components.

[0058] Assuming the ground voltage is 0V, such as Figure 3 As shown, when using the existing reverse connection protection circuit, when the voltage of the first electrode of the first power supply 110 (KL30, i.e., the yellow voltage waveform) drops to 0V (the red dashed line represents the 0V reference line of KL30), the gate of the NMOS transistor Q1 still has voltage (G_Q7002, i.e., the blue voltage waveform). The NMOS transistor Q1 is not completely turned off, and the voltage of the first electrode of the first power supply 110 (KL30) and the output voltage of the NMOS transistor Q1 (KL30_P, i.e., the pink voltage waveform) are still decreasing synchronously, indicating that there is still reverse current at this time. However, when using the reverse connection protection circuit 100 of this utility model for reverse connection protection, as... Figure 4 As shown, when the voltage of the first electrode of the first power supply 110 (KL30, i.e., the yellow voltage waveform) has not yet dropped to 0V (the red dashed line represents the 0V reference line of KL30), the positive and negative polarities of the first power supply 110 have not been completely reversed, but the gate of the NMOS transistor Q1 has no voltage (G_Q7002, i.e., the blue voltage waveform), indicating that the NMOS transistor Q1 has been completely turned off. The output voltage of the NMOS transistor Q1 (KL30_P) remains unchanged, indicating that there is no reverse current. This achieves the early turn-off of the NMOS transistor Q1 before the positive and negative polarities of the first power supply 110 have been completely reversed.

[0059] It should be noted that, Figure 3 and Figure 4 The 0V reference lines for KL30, KL30_P, G_Q7002, and DRV8718_OUT_VCP can be determined based on their respective names and locations. For example, the red dashed line in the figure is the 0V reference line for KL30.

[0060] By comparison, it can be seen that by using the reverse connection protection circuit 100 in this utility model for reverse connection protection, the NMOS transistor Q1 can be turned off about 3ms in advance, and the gate of the NMOS transistor Q1 is controlled throughout the process.

[0061] In some implementation methods, please refer to Figure 5 The reverse connection protection circuit 100 also includes a second drive module 160, one end of which is electrically connected to the control terminal of the second switch module 130, and the other end of which is grounded.

[0062] The second drive module 160 is used to turn on the second switch module 130 and turn off the first switch module 120 when the voltage of the first electrode of the first power supply 110 is not higher than the second threshold; the second threshold is lower than the ground voltage.

[0063] In this embodiment, since the second drive module 160 is grounded, a current loop can only be formed between the second drive module 160, the second switch module 130, and the first electrode of the first power supply 110 when the voltage of the first electrode of the first power supply 110 is equal to or lower than the second threshold, for example, when the voltage difference between the vehicle ground and the first electrode of the first power supply 110 reaches 0.7V or more. At this time, the second drive module 160 provides drive current to the second switch module 130, so that the second switch module 130 is turned on and the first switch module 120 is turned off.

[0064] In some implementation methods, please refer to Figure 6 The second drive module 160 includes a second diode D2 and a fifth resistor R5. The cathode of the second diode D2 is electrically connected to the control terminal of the second switch module 130, and the anode of the second diode D2 is electrically connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is grounded.

[0065] In this embodiment, the cathode of the second diode D2 is specifically electrically connected to the base of the transistor Q2. When the voltage of the first electrode of the first power supply 110 is equal to or lower than the second threshold, a current loop is formed between the fifth resistor R5, the second diode D2, the fourth resistor R4, and the first electrode of the first power supply 110, thereby providing base current to the transistor Q2, causing the transistor Q2 to conduct and the NMOS transistor Q1 to turn off. No reverse current flows through the NMOS transistor Q1, effectively preventing damage to the components caused by reverse current.

[0066] As can be seen, the reverse connection protection circuit 100 provided by this utility model provides a dual-layer reverse connection protection mechanism. The first layer of protection mechanism is mainly implemented through the second driving module 160, the second switching module 130 and the first switching module 120. The specific principle is as follows: When the voltage of the first electrode of the first power supply 110 is equal to or lower than the second threshold, the current flows through the fifth resistor R5 and the second diode D2 to the base of the transistor Q2, making the transistor Q2 conduct. After the transistor Q2 conducts, it quickly pulls down the gate voltage of the NMOS transistor Q1, thereby turning off the NMOS transistor Q1. The reverse connection protection path is the fifth resistor R5 → the second diode D2 → the transistor Q2 → the NMOS transistor Q1. The second layer of protection mechanism is mainly implemented through the second power supply 150, the first driving module 140, the second switching module 130, and the first switching module 120. The specific principle is as follows: When the voltage of the first electrode of the first power supply 110 is equal to or lower than the first threshold (i.e., VCC*r2 / (r1+r2)-0.7), the second power supply 150 provides base current to the transistor Q2 through the first resistor R1 and the first diode D1, so that the transistor Q2 is turned on; after the transistor Q2 is turned on, it quickly pulls down the gate voltage of the NMOS transistor Q1, thereby turning off the NMOS transistor Q1 in advance; the reverse connection protection path is the first resistor R1 → the first diode D1 → the transistor Q2 → the NMOS transistor Q1.

[0067] It is important to understand that the first-level protection mechanism described above can achieve basic reverse connection protection, but its response time is relatively slow. Reverse connection protection can only be activated when the voltage at the first electrode of the first power supply 110 is equal to or lower than the second threshold (lower than ground voltage). The second-level protection mechanism, however, activates reverse connection protection when the voltage at the first electrode of the first power supply 110 is equal to or lower than the first threshold (higher than ground voltage, for example, VCC*r2 / (r1+r2)-0.7). This means that NMOS transistor Q1 can be turned off earlier, even before the polarity of the first power supply 110 has been completely reversed, thus accelerating the turn-off speed of NMOS transistor Q1 and achieving faster reverse connection protection.

[0068] This utility model also provides an electronic device that includes the aforementioned reverse connection protection circuit 100. This electronic device can be a vehicle's ECU, SCU, on-board sensors, on-board charger, or other equipment requiring reverse connection protection.

[0069] In summary, the reverse connection protection circuit and electronic device provided by this utility model include a first power supply, a first switch module, a second switch module, a first drive module, and a second power supply. When the voltage at the first electrode of the first power supply is not higher than a first threshold, the second power supply drives the second switch module to conduct through the first drive module, thereby turning off the first switch module. This achieves early shutdown of the first switch module before the polarity of the first power supply is completely reversed, effectively preventing damage to components from reverse current and solving the problem of insufficient timeliness of reverse connection protection in existing technologies. Furthermore, the reverse connection protection circuit also includes a second drive module. When the voltage at the first electrode of the first power supply is not higher than a second threshold, the second drive module turns on the second switch module, thereby turning off the first switch module. Through this dual-layer reverse connection protection mechanism, the reliability of the reverse connection protection is further improved. Even if one layer of the reverse connection protection mechanism fails, the other layer can still function, ensuring circuit safety.

[0070] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.

Claims

1. A reverse connection protection circuit, characterized in that, The reverse connection protection circuit includes a first power supply, a first switch module, a second switch module, a first drive module, and a second power supply. The first terminal of the first switch module is electrically connected to the first electrode of the first power supply, and the second terminal of the first switch module is electrically connected to the load. The first terminal of the second switch module is electrically connected to the first electrode of the first power supply, and the second terminal of the second switch module is electrically connected to the control terminal of the first switch module. The control terminal of the second switch module is electrically connected to the first drive module. The second power supply is electrically connected to the first drive module. The second power supply is used to drive the second switching module to turn on, thereby turning off the first switching module, when the voltage of the first electrode of the first power supply is not higher than a first threshold; the first threshold is higher than the ground voltage.

2. The reverse connection protection circuit according to claim 1, characterized in that, The first driving module includes a voltage divider unit and a first diode. The cathode of the first diode is electrically connected to the control terminal of the second switching module, and the anode of the first diode is electrically connected to the voltage divider unit. The voltage divider unit is also electrically connected to the second power supply.

3. The reverse connection protection circuit according to claim 2, characterized in that, The voltage divider unit includes a first resistor and a second resistor. One end of the first resistor is electrically connected to the anode of the first diode, and the other end of the first resistor is electrically connected to the second power supply. One end of the second resistor is electrically connected between the anode of the first diode and the first resistor, and the other end of the second resistor is grounded.

4. The reverse connection protection circuit according to claim 3, characterized in that, The first threshold is VCC*r2 / (r1+r2)-0.7, where VCC represents the voltage value provided by the second power supply, r1 represents the resistance value of the first resistor, and r2 represents the resistance value of the second resistor.

5. The reverse connection protection circuit according to claim 1, characterized in that, The first switching module includes an NMOS transistor and a third resistor. The source of the NMOS transistor is electrically connected to the first electrode of the first power supply, the gate of the NMOS transistor is electrically connected to the second terminal of the second switching module, and the drain of the NMOS transistor is electrically connected to the load. The third resistor is electrically connected between the source and the gate of the NMOS transistor.

6. The reverse connection protection circuit according to claim 5, characterized in that, The first switching module further includes a Zener diode, the anode of which is electrically connected to the source of the NMOS transistor, and the cathode of which is electrically connected to the gate of the NMOS transistor.

7. The reverse connection protection circuit according to claim 1, characterized in that, The second switching module includes a transistor and a fourth resistor. The base of the transistor is electrically connected to the first driving module, the collector of the transistor is electrically connected to the control terminal of the first switching module, and the emitter of the transistor is electrically connected to the first electrode of the first power supply. The fourth resistor is electrically connected between the base and emitter of the transistor.

8. The reverse connection protection circuit according to any one of claims 1-7, characterized in that, The reverse connection protection circuit also includes a second drive module, one end of which is electrically connected to the control terminal of the second switch module, and the other end of which is grounded. The second driving module is used to turn on the second switching module and turn off the first switching module when the voltage of the first electrode of the first power supply is not higher than the second threshold; the second threshold is lower than the ground voltage.

9. The reverse connection protection circuit according to claim 8, characterized in that, The second driving module includes a second diode and a fifth resistor. The cathode of the second diode is electrically connected to the control terminal of the second switching module, and the anode of the second diode is electrically connected to one end of the fifth resistor, while the other end of the fifth resistor is grounded.

10. An electronic device, characterized in that, Includes the reverse connection protection circuit as described in any one of claims 1-9.

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