Power supply reverse connection protection circuit and power supply circuit

Abstract

The present application relates to a power supply anti-reverse connection circuit and a power supply circuit. In the power supply anti-reverse connection circuit, the switch module uses two switch tubes in combination with a P-type MOS tube, which can turn off or turn on the P-type MOS tube according to the level of the ground terminal. When the power supply is short-circuited, the P-type MOS tube cuts off the loop in the main line, thereby protecting the components of the peripheral circuit. When used in power supply charging and discharging occasions, if the power supply is correctly connected, the low on-resistance of the P-type MOS tube can be used to achieve large current charging and discharging while generating a small heat rise; if the power supply is not correctly connected, the main line P-type MOS tube is turned off, the current loop is disconnected, and the power supply and peripheral circuits are protected. That is, the embodiment of the present application can be used for unidirectional anti-reverse connection and bidirectional anti-reverse connection, and has versatility; at the same time, the circuit is powerful, does not require an auxiliary power supply, is low in cost, can protect the power supply and peripheral circuits from damage, and has high reliability.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a power supply reverse connection protection circuit and a power supply circuit. Background Art

[0002] Power reverse polarity protection technology primarily includes physical-layer protection and circuit-layer protection. Physical protection employs physical structures to prevent reverse polarity during installation, such as in mobile phone battery installations and reverse polarity protection interfaces. While widely used, this approach is limited in flexibility. Circuit protection, on the other hand, utilizes a combination of integrated circuits (ICs) and discrete components to automatically implement reverse polarity protection, protecting the circuit from normal operation.

[0003] During the implementation process, the inventors found that there are at least the following problems in the traditional technology: the single-direction anti-reverse connection circuit design has a single function and cannot be reused for the anti-reverse connection of the integrated charging and discharging power supply. Summary of the Invention

[0004] Based on this, it is necessary to provide a power supply reverse connection protection circuit and a power supply circuit to address the problem that the traditional circuit reverse connection protection is not suitable for bidirectional charging and discharging occasions.

[0005] To achieve the above objectives, on the one hand, an embodiment of the present application provides a power supply reverse connection protection circuit, comprising:

[0006] P-type MOS transistor; the drain of the P-type MOS transistor is used to connect to the first electrode of the DC power supply, and the source of the P-type MOS transistor is used to connect to the voltage transmission port;

[0007] A ground terminal, used for connecting to a second electrode of a DC power supply;

[0008] The switch module includes a first switch tube and a second switch tube; a first electrode of the first switch tube is connected to the gate of the P-type MOS tube and is connected to the source of the P-type MOS tube via a first resistor; a second electrode of the first switch tube is connected to the ground terminal; a first electrode of the second switch tube is connected to the control electrode of the first switch tube and is connected to the source of the P-type MOS tube via a second resistor; a second electrode of the second switch tube is used to connect to the first electrode of a DC power supply; and a control electrode of the second switch tube is connected to the ground terminal.

[0009] When the level at the ground end of the switch module is greater than 0V, the P-type MOS tube is turned off.

[0010] In one embodiment, the first switch tube is an NPN transistor or an N-type MOS tube;

[0011] The second switch tube is an NPN transistor or an N-type MOS tube.

[0012] In one embodiment, the power reverse connection protection circuit further includes:

[0013] The current suppression circuit is connected between the drain of the P-type MOS tube and the first electrode of the DC power supply.

[0014] In one embodiment, the current suppression circuit includes an inductor;

[0015] A first end of the inductor is connected to the drain of the P-type MOS tube, and a second end of the inductor is used to connect to a first electrode of a DC power supply.

[0016] In one embodiment, the power reverse connection protection circuit further includes:

[0017] A voltage suppression circuit; a first end of the voltage suppression circuit is connected to the drain of the P-type MOS tube; a second end of the voltage suppression circuit is connected to the ground end.

[0018] In one embodiment, the voltage suppression circuit includes a first capacitor;

[0019] A first end of the first capacitor is connected to the drain of the P-type MOS tube; a second end of the first capacitor is connected to the ground end.

[0020] In one embodiment, the power reverse connection protection circuit further includes a second capacitor;

[0021] A first end of the second capacitor is connected to the gate of the P-type MOS tube; a second end of the second capacitor is connected to the ground end.

[0022] In one embodiment, the power reverse connection protection circuit further includes:

[0023] a third resistor connected between the first electrode of the first switch tube and the gate of the P-type MOS tube;

[0024] The fourth resistor is connected between the control electrode of the second switch tube and the ground terminal.

[0025] In one embodiment, the power reverse connection protection circuit further includes a charge and discharge module, wherein a first transmission port of the charge and discharge module is connected to the voltage transmission port, and a second transmission port of the charge and discharge module is connected to the ground terminal.

[0026] On the other hand, an embodiment of the present application further provides a power supply circuit, including:

[0027] DC power supply;

[0028] Such as the power supply reverse connection protection circuit mentioned above.

[0029] One of the above technical solutions has the following advantages and beneficial effects:

[0030] Based on the above structure, the switch module uses two switch tubes in combination with a P-type MOS tube, which can turn off or turn on the P-type MOS tube according to the level of the ground terminal. When the power supply is short-circuited, the P-type MOS tube cuts off the loop in the main line, thereby protecting the components of the peripheral circuit. When used in power charging and discharging situations, if the power supply is correctly connected, the low on-resistance of the P-type MOS tube can be used to achieve large current charging and discharging while generating a small heat rise; if the power supply is not correctly connected, the main line P-type MOS tube is turned off, the current loop is disconnected, and the power supply and peripheral circuits are protected. That is, the embodiment of the present application can be used for unidirectional anti-reverse connection and bidirectional anti-reverse connection, and has versatility; at the same time, the circuit is powerful, does not require an auxiliary power supply, is low in cost, can protect the power supply and peripheral circuits from damage, and has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of the preferred embodiments of the present application shown in the accompanying drawings. Like reference numerals indicate like parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual size, with the emphasis on illustrating the subject matter of the present application.

[0032] Figure 1 is a first schematic structural diagram of a power supply reverse connection protection circuit in one embodiment;

[0033] Figure 2 is a second schematic structural diagram of a power supply reverse connection protection circuit in one embodiment;

[0034] Figure 3 is a third schematic structural diagram of a power supply reverse connection protection circuit in one embodiment;

[0035] Figure 4 is a fourth schematic structural diagram of a power supply reverse connection protection circuit in one embodiment;

[0036] Figure 5 FIG. 1 is a schematic structural diagram of a power supply circuit in one embodiment. DETAILED DESCRIPTION

[0037] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0038] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element and integrated therewith, or there may be an intermediate element. The terms "first pole," "second pole," "first end," and "second end," and similar expressions used herein are for illustrative purposes only.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] Currently, both physical-layer and circuit-layer reverse polarity protection are widely used in the industry. Physical-structured reverse polarity protection is preferred for complex circuits, high integration, and high power applications, facilitating manufacturing. Circuit-level reverse polarity protection is more suitable for customized products with a high degree of freedom. However, physical reverse polarity protection cannot effectively design a reverse polarity protection interface for structures like the 18650 battery. Typical reverse polarity protection circuit designs are limited in functionality and can only be used for reverse polarity protection in a single direction, making them unsuitable for reverse polarity protection in integrated charging and discharging systems like lithium batteries. Furthermore, high-reliability power supply reverse polarity protection circuits typically require logic control and an auxiliary power supply, making their design complex and costly.

[0041] To this end, the multi-purpose power reverse connection protection circuit proposed in the embodiments of the present application has the advantage of scalable application. It is applicable to general power reverse connection protection circuits as well as more complex integrated charge and discharge lithium battery reverse connection protection circuits, greatly improving the versatility and universality of the reverse connection protection circuit. In industrial manufacturing or consumer electronics manufacturing, it can provide users with higher safety protection.

[0042] Specifically, the embodiments of the present application utilize a switch tube and a P-type MOS tube to achieve reverse connection protection in a variety of application contexts at a very low cost, and can be flexibly used in different occasions. The main features include:

[0043] 1. It replaces the general reverse polarity protection circuit. After detecting the reverse polarity of the power supply, it quickly turns off the P-type MOS tube switch and disconnects the system current loop, which has high reliability. Based on this, the embodiment of the present application can ensure that peripheral devices such as integrated chips are not damaged by the reverse polarity of the power supply in the unidirectional power reverse polarity protection circuit, and has strong anti-interference capability.

[0044] 2. Applicable to lithium battery charging and discharging integrated circuits. Lithium batteries charge and discharge in both directions. The general solution is to use physical structural design to prevent reverse polarity, but this approach obviously increases the difficulty of structural design. The embodiment of the present application can use the logic coordination of two switching tubes to drive the P-type MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) on or off, realizing circuit-level reverse polarity protection for integrated charging and discharging.

[0045] 3. The embodiment of the present application has the advantages of low cost and high reliability. It utilizes several discrete components to implement a universal anti-reverse polarity circuit design in a purely hardware logic manner. It does not require the participation of a controller and an auxiliary power supply, thus simplifying the design difficulty and reducing the difficulty of circuit application.

[0046] In one embodiment, a power supply reverse connection protection circuit is provided. Figure 1 Shown, including:

[0047] P-type MOS tube; the drain of the P-type MOS tube is used to connect to the first electrode of the DC power supply, and the source of the P-type MOS tube is used to connect to the voltage transmission port.

[0048] The ground terminal is used to connect to the second electrode of the DC power supply.

[0049] The switch module includes a first switching transistor and a second switching transistor. The first electrode of the first switching transistor is connected to the gate of a P-type MOS transistor and to the source of the P-type MOS transistor via a first resistor; the second electrode of the first switching transistor is connected to a ground terminal. The first electrode of the second switching transistor is connected to the control electrode of the first switching transistor and to the source of the P-type MOS transistor via a second resistor; the second electrode of the second switching transistor is used to connect to the first electrode of a DC power supply; and the control electrode of the second switching transistor is connected to a ground terminal.

[0050] When the level at the ground end of the switch module is greater than 0V, the P-type MOS tube is turned off.

[0051] Specifically, the power reverse connection protection circuit includes a P-type MOS transistor, a ground terminal, and a switch module. The drain of the P-type MOS transistor is connected to the first electrode of the DC power supply, and the source is connected to the voltage transmission port, and can be used to shut down or conduct the circuit between the DC power supply and the voltage transmission port. The ground terminal is connected to the second electrode of the DC power supply; each electrode connected to the ground terminal is electrically connected to the second electrode of the DC power supply. The switch module can drive the P-type MOS transistor to shut down or conduct according to the voltage level of the ground terminal. Specifically, the switch module includes at least two switch tubes; the drain of the P-type MOS transistor is connected to the first electrode of the DC power supply, the gate is connected to the first electrode of the first switch tube, and the source is connected to the power transmission port; and the source of the P-type MOS transistor is connected to the first electrode of the first switch tube via a first resistor, and is respectively connected to the first electrode of the second switch tube and the control electrode of the first switch tube via a second resistor; the second electrode of the first switch tube is connected to the ground terminal; the second electrode of the second switch tube is connected to the first electrode of the DC power supply, and the control electrode is connected to the ground terminal. For example, the second switch can be turned on or off based on the voltage level at the ground terminal. Furthermore, the first switch can be turned on or off based on the state of the second switch, thereby changing the gate-source voltage of the P-type MOS transistor, turning the P-type MOS transistor on or off, and thus achieving on-off control between the DC power supply and the voltage transmission port. For example, if the DC power supply is reversely connected, the voltage level at the ground terminal is raised, and the first switch in the switch module can remain off, causing the P-type MOS transistor to be cut off, thereby disconnecting the power supply circuit and protecting the power supply and peripheral circuits.

[0052] In one example, when the DC power supply is correctly connected, the P-type MOS tube is turned on due to the presence of its own body diode, and has provided stable power to the power transmission port; the body diode itself has a large conduction voltage drop and large power consumption. At this time, since the level of the ground terminal is 0, the first switch tube in the switch module can remain in the on state, so that the P-type MOS tube is fully turned on, and electric energy is output from the MOS tube with low conduction impedance, providing safe power to the power transmission port, while significantly reducing the power consumption of the MOS tube.

[0053] Based on this, regardless of the mode in which the DC power supply discharges the voltage transmission port or the mode in which the voltage transmission port charges the DC power supply, the switch module can confirm whether the DC power supply is reversely connected based on the level change of the ground terminal, and can shut down the power supply circuit through the P-type MOS tube when the DC power supply is reversely connected.

[0054] It should be noted that the drain of the P-type MOS transistor is connected to the first electrode of the DC power supply, and the source is connected to the voltage transmission port. When the DC power supply is correctly connected, the instantaneous current can be transmitted from the source through the body diode of the P-type MOS transistor. For example, the P-type MOS transistor can be a P-channel MOS transistor. The switch module is used to shut down the P-type MOS transistor when the DC power supply is reversely connected. On the premise of achieving this logical function, the first and second switch transistors can be selected according to actual needs, such as switching transistors or MOS transistors of corresponding types. At the same time, the first and second resistors can be used to protect the switch transistors, and their resistance values ​​can be set according to actual circuit requirements. It should be noted that the circuit connection structure in the switch module can be designed according to actual needs. The selection of the switch transistor is related to the specific circuit design and is not specifically limited here. At the same time, the switch module may also include other switch transistors or devices to protect, expand, or match the operating requirements of peripheral circuits, such as current limiting resistors, pull-up resistors, inverters, and voltage divider resistors, etc., which are not specifically limited here. It should also be noted that the switch tube and MOS tube in the embodiment of the present application can operate in the saturation and cut-off regions, acting as switches without any amplification requirements. That is, the embodiment of the present application uses hardware logic relationships to achieve bidirectional circuit reverse connection protection, with high reliability and stability.

[0055] The voltage transmission port is used to connect to an external system or peripheral circuit; specifically, the voltage transmission port can power the system based on a DC power supply, or can charge the DC power supply based on the system. The DC power supply involved in the embodiments of the present application can be a DC power supply that powers the system, or can be a reserve battery for the system, capable of both powering the system and receiving charging from the system.

[0056] The circuit topology of the embodiments of the present application features high reliability, low cost, and strong versatility. It can be expanded to various applications and supports reverse polarity protection in bidirectional charging and discharging scenarios. Specifically, the embodiments of the present application can be used in situations where reverse polarity protection is traditionally required, without the need for an auxiliary power supply, resulting in low cost and a purely hardware-based implementation. The circuit topology is simple and highly reliable.

[0057] The embodiment of the present application supports lithium battery charge and discharge management applications, which can prevent the battery reverse connection from causing irreversible damage to the system; when the lithium battery is normally connected, the lithium battery can power the system normally, and can also be charged by an external power supply, realizing bidirectional circuit integration; if the lithium battery is reversely connected, the switch module drives the P-type MOS tube to cut off the current loop according to the level change of the ground terminal, thereby achieving the purpose of protecting the system.

[0058] In one embodiment, Figure 2 As shown, the first switch tube Q1 is an NPN transistor.

[0059] Specifically, the first switching transistor Q1 can be an NPN transistor, with its collector connected to the gate of the P-type MOS transistor Q3 and to the source of the P-type MOS transistor Q3 via a first resistor. The emitter of the first switching transistor Q1 is connected to ground, and its base is connected to the first electrode of the second switching transistor Q2 and to the source of the P-type MOS transistor Q3 via a second resistor. Furthermore, the first resistor can be a pull-up resistor that can function as a current limiter, and its resistance value can be set according to actual circuit requirements.

[0060] In one embodiment, the first switch tube is an N-type MOS tube.

[0061] Specifically, the first switch tube can be an N-type MOS tube, the drain of which is connected to the gate of the P-type MOS tube and to the source of the P-type MOS tube through a first resistor; the source of the first switch tube is connected to the ground end, the gate is connected to the first electrode of the second switch tube, and is connected to the source of the P-type MOS tube through a second resistor.

[0062] In one embodiment, Figure 2 As shown, the second switch tube Q2 is an NPN transistor.

[0063] Specifically, the collector of the second switching transistor Q2 is connected to the control electrode of the first switching transistor Q1 and, via a second resistor, to the source of the P-type MOS transistor Q3. The emitter of the second switching transistor Q2 is connected to the first electrode of the DC power supply, and the base is connected to ground and to the second electrode of the DC power supply. Furthermore, the second resistor can be a pull-up resistor that can provide current limiting, and its resistance value can be set based on actual circuit requirements.

[0064] In one embodiment, the second switch tube is an N-type MOS tube.

[0065] Specifically, the drain of the second switching tube is connected to the control electrode of the first switching tube and is connected to the source of the P-type MOS tube through a second resistor; the source of the second switching tube is connected to the first electrode of the DC power supply, and the gate is connected to the ground end and the second electrode of the DC power supply.

[0066] In one embodiment, the power reverse connection protection circuit further includes:

[0067] The current suppression circuit is connected between the drain of the P-type MOS tube and the first electrode of the DC power supply.

[0068] Specifically, a current suppression circuit is provided between the drain of the P-type MOS transistor and the first electrode of the DC power supply. The current suppression circuit is used to suppress current transients when the DC power supply is connected, mitigate the impact on the MOS transistor at the moment the DC power supply is connected, protect the MOS transistor, and further improve the reliability of the embodiments of the present application. By way of example, the current suppression circuit can be implemented using an existing inrush current suppression circuit, can also be primarily implemented using an inductor, and can also be configured based on the actual power supply specifications, which is not specifically limited here.

[0069] In one embodiment, the current suppression circuit includes an inductor; a first end of the inductor is connected to the drain of the P-type MOS transistor, and a second end of the inductor is used to connect to a first electrode of a DC power supply.

[0070] Specifically, an inductor is provided between the drain of the P-type MOS transistor and the first electrode of the DC power supply, which can be used to suppress current transients, reduce the impact of the DC power supply on the MOS transistor at the moment of access, and reduce the cost of the current suppression circuit.

[0071] In one embodiment, the power reverse connection protection circuit further includes:

[0072] A voltage suppression circuit; a first end of the voltage suppression circuit is connected to the drain of the P-type MOS tube; a second end of the voltage suppression circuit is connected to the ground end.

[0073] Specifically, a voltage suppression circuit is provided between the drain of the P-type MOS transistor and the second electrode of the DC power supply to suppress sudden voltage changes at the source of the P-type MOS transistor, thereby mitigating the impact on the MOS transistor when the power is connected, protecting the MOS transistor, and further improving the reliability of the embodiments of the present application. For example, the voltage suppression circuit can be implemented using an existing surge voltage suppression circuit, or can be primarily implemented using a capacitor, and can also be configured according to the actual power supply specifications, which is not specifically limited here.

[0074] In one embodiment, the voltage suppression circuit includes a first capacitor; a first end of the first capacitor is connected to the drain of the P-type MOS transistor; and a second end of the first capacitor is connected to the ground.

[0075] Specifically, a first capacitor is provided between the drain of the P-type MOS transistor and the second electrode of the DC power supply, which can be used to suppress the voltage mutation at the source of the P-type MOS transistor, thereby reducing the impact on the MOS transistor when the power is connected and reducing the cost of the voltage suppression circuit.

[0076] In one embodiment, the power reverse connection protection circuit further includes a second capacitor; a first end of the second capacitor is connected to the gate of the P-type MOS transistor; and a second end of the second capacitor is connected to the ground.

[0077] Specifically, a second capacitor is provided between the gate of the P-type MOS tube and the second pole of the DC power supply; the second capacitor serves as a bypass capacitor, which can be used to prevent impact on the gate of the P-type MOS tube, protect the MOS tube, and further improve the reliability of the embodiment of the present application.

[0078] In one embodiment, the power reverse connection protection circuit further includes:

[0079] The third resistor is connected between the first electrode of the first switch tube and the gate of the P-type MOS tube.

[0080] Specifically, a third resistor is provided between the first electrode of the first switching tube and the gate of the P-type MOS tube, which can act as a buffer to prevent impact on the gate of the P-type MOS tube, protect the MOS tube, and further improve the reliability of the embodiment of the present application.

[0081] In one embodiment, the power reverse connection protection circuit further includes:

[0082] The fourth resistor is connected between the control electrode of the second switch tube and the ground terminal.

[0083] Specifically, a fourth resistor is provided between the control electrode and the ground terminal of the second switch tube, which can play a current limiting role, prevent the impact of reverse connection of the DC power supply on the second switch tube, protect the switch module, and further improve the reliability of the embodiment of the present application.

[0084] In one example, if Figure 3 As shown, V OUT It is used to provide safe power supply to the subsequent system. When DC power supply is connected, the power supply is normal when the upper side is positive and the lower side is negative. Since the GND (ground terminal) level is 0, the base input current of Q2 is 0. As the NPN transistor Q2 is turned off, the base level of Q1 is pulled high, the NPN transistor Q1 is saturated and turned on, the collector level of Q1 is pulled low, and the Vgs of the P-type MOS tube Q3 is -V DC , so Q3 is turned on, the output voltage V OUT , providing a safe power supply for the system. Once the DC power supply is reversed, as analyzed above, the P-type MOS tube Q3 is turned off, the power current loop is shut off, and the system is safely protected.

[0085] Specifically, at the moment the DC power supply DC is connected, the inductor L1 suppresses current transients, and the first capacitor C1 suppresses the sudden change in the source voltage of the P-type MOS tube Q3, thereby reducing the impact on the MOS tube at the moment the power supply is connected and protecting the MOS tube from damage. The power supply is connected positively at the top and negatively at the bottom. Due to the presence of its own body diode, the P-type MOS tube Q3 is turned on and the switch tube is turned on, providing a stable power supply to the system. However, the body diode itself has a large conduction voltage drop and a large power consumption. Then, because the GND level is 0, the base input current of Q2 is 0, and the NPN transistor Q2 is turned off. At this time, the base level of Q1 is pulled up, the NPN transistor Q1 is saturated and turned on, the collector level of Q1 is pulled down, and the Vgs of the P-type MOS tube Q3 is -V DC , so Q3 is fully turned on, and the power provided to the system by the body diode is converted into power flowing through the MOS tube with low on-resistance, providing a safe power supply for the system; at the same time, the power consumption of the MOS tube itself is greatly reduced. However, once the DC power supply is reversed, the ground level is pulled high, the positive input voltage is pulled low, and the base level of Q2 is pulled high, turning on the NPN transistor Q2. At this time, the base level of Q1 is pulled low, the NPN transistor Q1 is turned off, and the collector level of Q1 is pulled high. The Vgs of the P-type MOS tube Q3 is V OUT ≥0, so Q3 is turned off, the power circuit is shut down, thereby achieving the purpose of preventing reverse connection. The P-type MOS tube is turned off, the power current circuit is shut down, and the system is safely protected.

[0086] In one embodiment, the power reverse connection protection circuit further includes a charge and discharge module; a first transmission port of the charge and discharge module is connected to the voltage transmission port, and a second transmission port of the charge and discharge module is connected to the ground terminal.

[0087] Specifically, the power supply reverse connection protection circuit may also be provided with a charge and discharge module. The first transmission port of the charge and discharge module is connected to the voltage transmission port, and the second transmission port is connected to the second electrode of the DC power supply; based on this, the charge and discharge module can supply power to the system or peripheral circuit based on the DC power supply, and can also charge the DC power supply based on the external power supply. Furthermore, the charge and discharge module may also include a first electrode and a second electrode for connecting to an external circuit. In one example, the charge and discharge module also includes a power port for connecting to the system main power supply; based on this, the system main power supply can serve as the main power supply for the system or peripheral circuit, and the DC power supply serves as a backup power supply; the system main power supply can supply power to the system or peripheral circuit, and can also charge the DC power supply through the charge and discharge module. Specifically, the charge and discharge module can be used to manage the charge and discharge of the DC power supply, and can be mainly composed of a charge and discharge chip and a power port, etc., and is not specifically limited thereto.

[0088] In one example, if Figure 4 As shown, V SYSUsed to provide safe power supply to the subsequent system; when the lithium battery power supply is connected, V2 can be used as a charging and discharging power supply interface to supply voltage to the system, and can also be used as the system's total power supply to charge the lithium battery. As long as the positive and negative ends of the lithium battery are connected normally, the GND level is 0, the base input current of Q2 is 0, and the NPN transistor Q2 is turned off. At this time, the base level of Q1 is pulled high, the NPN transistor Q1 is saturated and turned on, the collector level of Q1 is pulled low, and the Vgs of the P-type MOS tube Q3 is -V Battery , so Q3 is turned on, the output voltage or input voltage is V2, providing a safe power supply for the system, and the output voltage after the lithium battery charge and discharge module is V SYS Alternatively, the system's main power supply can safely charge the lithium battery through the lithium battery charge and discharge management solution. However, if the lithium battery is reversely connected, as analyzed above, the P-type MOSFET turns off, severing the lithium battery charge and discharge circuit, protecting the system and the lithium battery. Furthermore, if the system's main power supply is connected at this time, the system can still operate normally.

[0089] Specifically, considering that non-standard factory production or improper user use may cause the lithium battery to be connected to the circuit in the reverse direction, the embodiment of the present application can also be used in circuits where the reverse connection object is a lithium battery. Specifically, VCC is the system's total power supply, and the lithium battery serves as an auxiliary power supply. When VCC provides power to the system, it can charge the lithium battery. When VCC is not connected, the auxiliary power supply lithium battery provides power to the system. When the lithium battery is reversely connected and VCC is connected, the system charges the negative pole of the lithium battery, affecting the battery life; if the lithium battery is reversely connected and VCC is not connected, the lithium battery provides energy to the system. Due to the negative voltage connection, the system will be damaged, causing irreversible damage.

[0090] The system's main power supply and auxiliary power supply lithium batteries can both power the system through the charge and discharge module. The system output power is only one V SYS The system can operate with either the main power supply or the lithium battery. Due to the anti-reverse polarity circuit, even if the lithium battery is connected in reverse, the system will not be damaged. If the main power supply is present, the system will still operate normally.

[0091] When the lithium battery is connected normally, the inductor L1 suppresses current transients, and the first capacitor C1 suppresses sudden changes in the source voltage of the P-type MOS tube, thereby reducing the impact on the MOS tube when the power is connected, and protecting the MOS tube from damage. The lithium battery is connected with positive on the top and negative on the bottom. If there is no system main power supply VCC connected, the P-type MOS tube has its own body diode, and the switch tube is turned on, providing a stable power supply to the system. However, the body diode itself has a large conduction voltage drop, and the power consumption is large. Then, because the GND level is 0, the base input current of Q2 is 0, and the NPN transistor Q2 is turned off. At this time, the base level of Q1 is pulled high, the NPN transistor Q1 is saturated and turned on, the collector level of Q1 is pulled low, and the Vgs of the P-type MOS tube Q3 is -V Battery Therefore, Q3 is fully turned on, and the power provided by the system to the body diode is changed to flow through the MOS tube with low on-resistance to output power, thereby providing a safe power supply V for the system. SYS At the same time, the power consumption of the MOS tube itself is greatly reduced.

[0092] If the system main power supply VCC is connected, as described above, the Vgs of the P-type MOS tube Q3 is -V Battery , Q3 is fully turned on, the system's total power supply is converted to V2, and the lithium battery can be managed and charged. Once the lithium battery is reversed, the ground level is pulled high, the positive input voltage is pulled low, the base level of Q2 is pulled high, and the NPN transistor Q2 is turned on. At this time, the base level of Q1 is pulled low, the NPN transistor Q1 is turned off, the collector level of Q1 is pulled high, and the Vgs of the P-type MOS tube Q3 is V2 ≥ 0, so Q3 is turned off, the battery access circuit is cut off, and the lithium battery cannot be charged or discharged, thereby achieving the purpose of preventing reverse connection and protecting the system safely; at this time, the total power supply VCC and V SYS The output is normal and does not affect the normal operation of the system.

[0093] In one embodiment, a power supply circuit is provided, comprising:

[0094] DC power supply;

[0095] Such as the power supply reverse connection protection circuit mentioned above.

[0096] Specifically, the power reverse polarity protection circuit connects the two electrodes of the DC power supply. When the DC power supply is reversely connected, it immediately disconnects the power circuit to protect the power supply and peripheral circuits. The DC power supply can be a unidirectional power supply or a charge-discharge power supply.

[0097] In one example, if Figure 5As shown, V1 can be the DC power supply for the system or a backup power source (lithium battery). As long as V1 is connected correctly and not reverse polarity, the base input current of Q2 is zero, turning off the NPN transistor Q2. At this time, the base voltage of Q1 is pulled high, causing the NPN transistor Q1 to saturate and conduct. The collector voltage of Q1 is pulled low, and the Vgs of the P-type MOS transistor Q3 is -V1, turning on Q3. Based on this, the reverse polarity protection function can be achieved in the same circuit topology for both bidirectional charging and discharging of the power supply. If V1 is reverse polarity, the ground voltage is pulled high, the positive input voltage is pulled low, and the base voltage of Q2 is pulled high, turning on the NPN transistor Q2. At this time, the base voltage of Q1 is pulled low, turning off the NPN transistor Q1, and the collector voltage of Q1 is pulled high. The Vgs of the P-type MOS transistor Q3 is V2-V1 (V1=0V), so Q3 is turned off, and the power circuit is shut down, thus achieving the reverse polarity protection function.

[0098] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A power supply anti-reverse connection circuit, characterized in that: include: A P-type MOS transistor; the drain of the P-type MOS transistor is used to connect to the first electrode of the DC power supply, and the source of the P-type MOS transistor is used to connect to the voltage transmission port; a ground terminal, configured to connect to the second electrode of the DC power supply; The switch module includes a first switch tube and a second switch tube; a first electrode of the first switch tube is connected to the gate of the P-type MOS tube and is connected to the source of the P-type MOS tube via a first resistor; a second electrode of the first switch tube is connected to the ground terminal; a first electrode of the second switch tube is connected to the control electrode of the first switch tube and is connected to the source of the P-type MOS tube via a second resistor; The second electrode of the second switching tube is used to connect to the first electrode of the DC power supply; the control electrode of the second switching tube is connected to the ground terminal; the second switching tube is turned on or off according to the voltage level of the ground terminal, and the first switching tube is turned on or off according to the state of the second switching tube, so as to change the gate-source voltage of the P-type MOS tube and turn the P-type MOS tube on or off; The switch module turns off the P-type MOS tube when the voltage level of the ground terminal is greater than 0V.

2. The power supply anti-reverse connection circuit according to claim 1, characterized in that: The first switch tube is an NPN transistor or an N-type MOS tube; The second switch tube is an NPN transistor or an N-type MOS tube.

3. The power supply anti-reverse connection circuit according to claim 1, characterized in that: Also includes: The current suppression circuit is connected between the drain of the P-type MOS tube and the first electrode of the DC power supply.

4. The power supply reverse connection protection circuit according to claim 3, characterized in that: The current suppression circuit includes an inductor; The first end of the inductor is connected to the drain of the P-type MOS transistor, and the second end of the inductor is used to connect to the first electrode of the DC power supply.

5. The power supply anti-reverse connection circuit according to claim 1, characterized in that: Also includes: Voltage suppression circuit; The first end of the voltage suppression circuit is connected to the drain of the P-type MOS tube; The second terminal of the voltage suppression circuit is connected to the ground terminal.

6. The power supply anti-reverse connection circuit according to claim 5, characterized in that: The voltage suppression circuit includes a first capacitor; The first end of the first capacitor is connected to the drain of the P-type MOS tube; the second end of the first capacitor is connected to the ground end.

7. The power supply reverse connection protection circuit according to any one of claims 1 to 6, characterized in that: Also including a second capacitor; A first end of the second capacitor is connected to the gate of the P-type MOS transistor; a second end of the second capacitor is connected to the ground end.

8. The power supply reverse connection protection circuit according to any one of claims 1 to 6, characterized in that: Also includes: a third resistor connected between the first electrode of the first switch tube and the gate of the P-type MOS tube; A fourth resistor is connected between the control electrode of the second switch tube and the ground terminal.

9. The power supply reverse connection protection circuit according to any one of claims 1 to 6, characterized in that: Also includes a charging and discharging module; The first transmission port of the charging and discharging module is connected to the voltage transmission port, and the second transmission port of the charging and discharging module is connected to the ground terminal.

10. A power supply circuit, characterized in that: include: DC power supply; The power supply reverse connection protection circuit according to any one of claims 1 to 9.

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