CN110890749A - Power supply reverse connection prevention circuit and power supply circuit - Google Patents

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 to match the P-type MOS tube, and 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 circuit in the main road, thereby protecting the components of the peripheral circuit. When used in power supply charging and discharging occasions, if the power supply is connected correctly, the low on-resistance of the P-type MOS transistor can be used to realize high current charge and discharge and generate a small heat rise; if the power supply is not connected correctly, the main circuit P The 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 one-way anti-reverse connection and two-way anti-reverse connection, and has versatility; at the same time, the circuit has powerful functions, no auxiliary power supply, low cost, can protect the power supply and peripheral circuits from damage, and has high reliability sex.

Description

Power supply anti-reverse circuit and power circuit

technical field

The present application relates to the technical field of circuits, and in particular, to a power supply anti-reverse connection circuit and a power supply circuit.

Background technique

The power supply anti-reverse connection technology mainly includes the physical layer anti-reverse connection and the circuit layer anti-reverse connection. Physical anti-reverse connection is to use physical structure to prevent reverse connection in installation, such as mobile phone battery installation, anti-reverse connection interface, etc.; although its application is very extensive, this method is not flexible enough. The circuit anti-reverse connection is the use of integrated circuit IC (Integrated Circuit) and discrete components to automatically realize the anti-reverse connection function and protect the circuit from working normally.

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

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a power supply anti-reverse connection circuit and a power supply circuit in view of the problem that the traditional circuit anti-reverse connection is not suitable for bidirectional charging and discharging occasions.

In order to achieve the above purpose, on the one hand, an embodiment of the present application provides a power supply anti-reverse connection circuit, including:

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

a ground terminal, used to connect the second electrode of the DC power supply;

The switch module includes a first switch tube and a second switch tube; the first pole 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 through a first resistor; The second pole is connected to the ground terminal; the first pole of the second switch tube is connected to the control pole of the first switch tube, and is connected to the source of the P-type MOS tube through the second resistor; the second pole of the second switch tube is used to connect DC The first electrode of the power supply; the control electrode of the second switch tube is connected to the ground terminal;

The switch module turns off the P-type MOS tube when the level of the ground terminal is greater than 0V.

In one of the embodiments, the first switch transistor is an NPN-type triode or an N-type MOS transistor;

The second switch tube is an NPN type triode or an N type MOS tube.

In one of the embodiments, the power supply anti-reverse connection circuit further includes:

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

In one of the embodiments, 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.

In one of the embodiments, the power supply anti-reverse connection circuit further includes:

a voltage suppression circuit; the first end of the voltage suppression circuit is connected to the drain of the P-type MOS transistor; the second end of the voltage suppression circuit is connected to the ground terminal.

In one of the embodiments, 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 transistor; the second end of the first capacitor is connected to the ground end.

In one of the embodiments, the power supply anti-reverse connection circuit further includes a second capacitor;

The first end of the second capacitor is connected to the gate of the P-type MOS transistor; the second end of the second capacitor is connected to the ground end.

In one of the embodiments, the power supply anti-reverse connection circuit further includes:

The third resistor is connected between the first pole of the first switch tube and the gate of the P-type MOS tube;

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

In one of the embodiments, the power supply anti-reverse connection circuit further 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.

On the other hand, an embodiment of the present application also provides a power supply circuit, including:

DC power supply;

Such as the above-mentioned power supply anti-reverse circuit.

A technical scheme in the above-mentioned technical scheme has the following advantages and beneficial effects:

Based on the above structure, the switch module uses two switch tubes to match with the P-type MOS tube, and 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 circuit in the main road, 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 transistor can be used to achieve high current charging and discharging and generate a small heat rise; if the power supply is not correctly connected, the main circuit P The 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 one-way anti-reverse connection and two-way anti-reverse connection, and has versatility; at the same time, the circuit has powerful functions, no auxiliary power supply, low cost, can protect the power supply and peripheral circuits from damage, and has high reliability sex.

Description of drawings

The above and other objects, features and advantages of the present application will become more apparent from a more detailed description of the preferred embodiments of the present application shown in the accompanying drawings. The same reference numerals refer to the same parts throughout the drawings, and the drawings are not intentionally drawn to scale, the emphasis being placed on illustrating the subject matter of the present application.

1 is a first schematic structural diagram of a power supply anti-reverse connection circuit in one embodiment;

2 is a second schematic structural diagram of a power supply anti-reverse connection circuit in one embodiment;

3 is a third schematic structural diagram of a power supply anti-reverse connection circuit in one embodiment;

4 is a fourth schematic structural diagram of a power supply anti-reverse connection circuit in one embodiment;

FIG. 5 is a schematic structural diagram of a power supply circuit in an embodiment.

Detailed ways

In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the related drawings. Preferred embodiments of the present application are shown in the accompanying drawings. However, the application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It should be noted that when an element is referred to as being "connected" to another element, it can be directly connected to and integrated with the other element, or intervening elements may also be present. The terms "first pole", "second pole", "first end", and "second end" and similar expressions are used herein for illustrative purposes only.

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

At present, the physical layer anti-reverse connection and the circuit layer anti-reverse connection are widely used in the industry. For occasions such as complicated circuits, high integration, high power, etc., the physical structure type anti-reverse connection is selected, which is easy to manufacture; and for customized products, For occasions with high degrees of freedom, it is more appropriate to use circuit-level anti-reverse connection. However, the physical anti-reverse connection cannot be designed with an effective anti-reverse connection interface for structures such as 18650 batteries; the general anti-reverse connection circuit has a single design function and can only be used as a single-direction circuit for anti-reverse connection, and cannot be reused such as charging and discharging. The anti-reverse connection of the integrated lithium battery is in progress; and generally, the high-reliability power supply anti-reverse connection circuit requires logic control and auxiliary power supply, which is complicated in design and high in cost.

For this reason, a multi-purpose power supply anti-reverse connection circuit proposed in the embodiment of the present application has the advantage of being expandable and applicable, and is suitable for general power supply anti-reverse connection circuits, as well as more complex charging and discharging integrated lithium batteries. Anti-reverse circuit, greatly improving the versatility and universality of anti-reverse circuit. In industrial manufacturing or consumer electronics manufacturing, it can provide users with high security.

Specifically, the embodiment of the present application realizes the anti-reverse connection function under various application backgrounds at a very low cost through the combination of a switch tube and a P-type MOS tube, and can be flexibly used in different occasions. The main features include:

1. Instead of the general anti-reverse connection circuit, after detecting the reverse connection of the power supply, the P-type MOS tube switch is quickly turned off to disconnect the system current loop, and the reliability is high; In the reverse connection circuit, it is ensured that peripheral devices such as integrated chips are not damaged by the reverse connection of the power supply, and the anti-interference ability is strong.

2. It can be applied to the integrated circuit of lithium battery charging and discharging. The lithium battery is charged and discharged in both directions. The general solution is to use the physical structure design to prevent reverse connection, but this method obviously increases the difficulty of structural design. In the embodiment of the present application, the logic cooperation of two switching transistors can be used to drive a P-type MOS transistor (Metal-Oxide-Semiconductor Field-Effect Transistor) to be turned on or off, so as to realize the integrated circuit level of charging and discharging. Anti-reverse connection.

3. The embodiment of the present application has the advantages of low cost and high reliability, and uses several discrete components to realize the design of a general-purpose anti-reverse connection circuit in a purely hardware logic manner, without the participation of a controller and an auxiliary power supply, simplifying the design difficulty, Reduce the difficulty of circuit application.

In one embodiment, a power supply anti-reverse connection circuit is provided, as shown in FIG. 1 , including:

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.

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

The switch module includes a first switch tube and a second switch tube. The first pole 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 through a first resistor; the second pole of the first switch tube is connected to the ground terminal. The first pole of the second switch tube is connected to the control pole of the first switch tube, and is connected to the source pole of the P-type MOS tube through the second resistor; the second pole of the second switch tube is used to connect the first electrode of the DC power supply; The control electrodes of the two switches are connected to the ground terminal.

The switch module turns off the P-type MOS tube when the level of the ground terminal is greater than 0V.

Specifically, the power supply anti-reverse connection circuit includes a P-type MOS tube, 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, which can be used to turn off or turn on the loop 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 turn off or turn on according to the level of the ground terminal. Specifically, the switch module includes at least two switch tubes; the drain of the P-type MOS tube is connected to the first electrode of the DC power supply, the gate is connected to the first pole of the first switch tube, and the source is connected to the power transmission port; The source of the MOS tube is connected to the first pole of the first switch tube through a first resistor, and is respectively connected to the first pole of the second switch tube and the control pole of the first switch tube through a second resistor; The pole is connected to the ground terminal; the second pole of the second switch tube is connected to the first pole of the DC power supply, and the control pole is connected to the ground terminal. Exemplarily, the second switch tube can be turned on or off according to the level of the ground terminal. Further, the first switch tube can be turned on or off according to the state of the second switch tube, and then the gate of the P-type MOS tube can be changed. The size of the source voltage, turn on or off the P-type MOS tube, and realize the on-off control between the DC power supply and the voltage transmission port. For example, when the DC power supply is reversely connected, the level of the ground terminal is pulled high, and the first switch tube in the switch module can be kept disconnected, so as to cut off the P-type MOS tube, thereby disconnecting the power supply loop to protect the power supply and peripherals. circuit.

In one example, when the DC power supply is connected correctly, the P-type MOS transistor is turned on due to the existence of its own body diode, which has provided a stable power supply to the power transmission port; the body diode itself has a large conduction voltage drop and consumes a large amount of power. , at this time, since the level of the ground terminal is 0, the first switch tube in the switch module can be kept on, so that the P-type MOS tube is completely turned on, and the power is output from the low on-resistance MOS tube for power transmission. The port passes the safety power supply, and at the same time greatly reduces the power consumption of the MOS tube.

Based on this, regardless of whether the DC power supply discharges the voltage transmission port or the voltage transmission port charges the DC power supply, the switch module can confirm whether the DC power supply is reversed according to the level change of the ground terminal When the DC power supply is reversed, the power circuit is turned off through the P-type MOS tube.

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; the instantaneous current when the DC power supply is correctly connected can be transmitted from the source through the body diode of the P-type MOS transistor out; exemplarily, the P-type MOS transistor can be a P-channel MOS transistor. The switch module is used to turn off the P-type MOS tube when the DC power supply is reversely connected; on the premise of realizing this logic function, the first switch tube and the second switch tube can choose the corresponding type of switch transistor or MOS tube according to actual needs etc. At the same time, the first resistor and the second resistor can be used to protect the switch tube, 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, and the selection of the switch tube is related to the specific circuit design, which is not specifically limited here; at the same time, the switch module can also include other switch tubes or devices. , used to protect, expand or match the working requirements of peripheral circuits, such as current limiting resistors, pull-up resistors, inverters, and voltage divider resistors, which are not specifically limited here. It should also be noted that both the switch tube and the MOS tube in the embodiment of the present application can work in the saturation and cut-off regions, and play a switching role without amplification requirements. Reverse connection, with high reliability and stability.

The voltage transmission port is used to connect external systems or peripheral circuits, etc. Specifically, the voltage transmission port can supply power to the system based on the DC power supply, and can also charge the DC power supply based on the system. The DC power supply involved in the embodiments of the present application may be a DC power supply for supplying power to the system, and may also be a reserve battery of the system, which can supply power to the system and also accept charging of the system.

The circuit topology of the embodiments of the present application has the characteristics of high reliability, low cost, strong versatility, etc., can support expansion and application to different directions, and support circuit reverse connection in the case of bidirectional charging and discharging. Specifically, the embodiments of the present application can be used in occasions requiring anti-reverse connection in the traditional sense, no auxiliary power supply is required, the cost is low, and is implemented by pure hardware, the circuit topology is simple, and the reliability is high.

The embodiment of the present application supports the application of lithium battery charge and discharge management, which can prevent irreversible damage to the system caused by the anti-reverse connection of the battery; when the lithium battery is connected normally, the lithium battery can supply power to the system normally, or the lithium battery can be supplied by an external power supply Charging to achieve 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, so as to achieve the purpose of protecting the system.

In one embodiment, as shown in FIG. 2 , the first switch transistor Q1 is an NPN transistor.

Specifically, an NPN transistor can be selected for the first switch transistor Q1, the collector is connected to the gate of the P-type MOS transistor Q3, and the source of the P-type MOS transistor Q3 is connected through a first resistor; the emitter of the first switch transistor Q1 The ground terminal is connected, the base electrode is connected to the first electrode of the second switch transistor Q2, and the source electrode of the P-type MOS transistor Q3 is connected through a second resistor. Further, the first resistor can be a pull-up resistor, which can play the role of current limiting, and its resistance value can be set according to actual circuit requirements.

In one embodiment, the first switch transistor is an N-type MOS transistor.

Specifically, the first switch can be an N-type MOS transistor, the drain is connected to the gate of the P-type MOS transistor, and the source of the P-type MOS transistor is connected through a first resistor; the source of the first switch is connected to the ground terminal , the gate is connected to the first pole of the second switch tube, and is connected to the source of the P-type MOS tube through the second resistor.

In one embodiment, as shown in FIG. 2 , the second switch transistor Q2 is an NPN transistor.

Specifically, the collector of the second switch transistor Q2 is connected to the control electrode of the first switch transistor Q1, and is connected to the source of the P-type MOS transistor Q3 through a second resistor; the emitter of the second switch transistor Q2 is connected to the first electrode of the DC power supply. an electrode, the base electrode is connected to the ground terminal and is connected to the second electrode of the DC power supply. Further, the second resistor can be a pull-up resistor, which can play the role of current limiting, and its resistance value can be set according to actual circuit requirements.

In one embodiment, the second switch transistor is an N-type MOS transistor.

Specifically, the drain of the second switch is connected to the control electrode of the first switch, and is connected to the source of the P-type MOS transistor through a second resistor; the source of the second switch is connected to the first electrode of the DC power supply, and the gate The electrode is connected to the ground terminal and is connected to the second electrode of the DC power supply.

In one embodiment, the power supply anti-reverse connection circuit further includes:

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

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, slow down the impact on the MOS tube when the DC power supply is connected, protect the MOS tube, and further improve the reliability of the embodiments of the present application. Exemplarily, the current suppression circuit may be implemented by using an existing surge current suppression circuit, or may be implemented mainly by an inductance, and may also be set according to actual power supply specifications, which is not specifically limited here.

In one embodiment, 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 connected to the first electrode of the DC power supply.

Specifically, an inductance 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, slow down the impact of the DC power supply on the MOS transistor when the DC power supply is connected, and reduce the cost of the current suppression circuit .

In one embodiment, the power supply anti-reverse connection circuit further includes:

a voltage suppression circuit; the first end of the voltage suppression circuit is connected to the drain of the P-type MOS transistor; the second end of the voltage suppression circuit is connected to the ground terminal.

Specifically, a voltage suppression circuit is provided between the drain of the P-type MOS tube and the second pole of the DC power supply, which can be used to suppress the sudden change of the voltage of the source of the P-type MOS tube, thereby slowing down the moment when the power supply is connected to the MOS tube. impact, protect the MOS tube, and further improve the reliability of the embodiment of the present application. Exemplarily, the voltage suppression circuit may be implemented by using an existing surge voltage suppression circuit, or may be implemented mainly by a capacitor, and may also be set according to actual power supply specifications, which is not specifically limited here.

In one embodiment, 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 transistor; the second end of the first capacitor is connected to the ground.

Specifically, a first capacitor is provided between the drain of the P-type MOS tube and the second pole of the DC power supply, which can be used to suppress the sudden change of the voltage of the source of the P-type MOS tube, thereby slowing down the instantaneous effect of the power supply on the MOS tube. impact, and reduce the cost of the voltage suppression circuit.

In one embodiment, the power supply anti-reverse connection circuit further includes a second capacitor; the first end of the second capacitor is connected to the gate of the P-type MOS transistor; the second end of the second capacitor is connected to the ground terminal.

Specifically, a second capacitor is also provided between the gate of the P-type MOS tube and the second pole of the DC power supply; the second capacitor, as a bypass capacitor, can be used to prevent the impact on the gate of the P-type MOS tube, The MOS transistor is protected, and the reliability of the embodiment of the present application is further improved.

In one embodiment, the power supply anti-reverse connection circuit further includes:

The third resistor is connected between the first pole of the first switch tube and the gate of the P-type MOS tube.

Specifically, a third resistor is provided between the first pole of the first switch tube and the gate of the P-type MOS tube, which can play a buffer role, prevent the impact on the gate of the P-type MOS tube, and protect the MOS tube , further improving the reliability of the embodiments of the present application.

In one embodiment, the power supply anti-reverse connection circuit further includes:

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

Specifically, a fourth resistor is provided between the control pole of the second switch tube and the ground terminal, which can act as a current limiter, prevent the impact of the reverse connection of the DC power supply on the second switch tube, protect the switch module, and further improve the reliability of the embodiments of the present application.

In an example, as shown in Figure 3, V _OUT is used to provide a safe power supply for the post-stage system, the DC power supply is connected to DC, and the power supply is connected normally when the upper is positive and the lower is negative, because the GND (ground) level is 0 , the base input current of Q2 is 0, as 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, P-type MOS The Vgs of the tube Q3 is -V _DC , so Q3 is turned on and the output voltage V _OUT provides a safe power supply for the system. Once the DC power supply DC is reversed, the analysis is as above, the P-type MOS transistor Q3 is turned off, the power supply current loop is turned off, and the safety protection system.

Specifically, at the moment when the DC power supply DC is connected, the inductor L1 suppresses the current transient, and the first capacitor C1 suppresses the sudden change of the source voltage of the P-type MOS transistor Q3, thereby reducing the impact on the MOS transistor when the power supply is connected, and protecting the MOS transistor from damage. The upper and lower sides of the power supply are connected to the positive and the negative, and the P-type MOS transistor Q3 is turned on due to the existence of its own body diode, which has provided a stable power supply to the system. However, the body diode itself has a large conduction voltage drop and consumes a large amount of power. Then, since 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, and the collector level of Q1 Pulled down, the Vgs of the P-type MOS transistor Q3 is -V _DC , so Q3 is completely turned on, and the power supplied to the system through the body diode at the moment of access is changed to the power output by the MOS tube with low on-resistance , to provide 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 DC is reversed, the ground level is pulled high, the positive input voltage is pulled down, the base level of Q2 is pulled up, as the NPN transistor Q2 is turned on, and the base level of Q1 is pulled down at this time. , the NPN transistor Q1 is turned off, the collector level of Q1 is pulled high, the Vgs of the P-type MOS transistor Q3 is V _OUT ≥ 0, so Q3 is turned off, and the power circuit is turned off, so as to achieve the purpose of preventing reverse connection. The P-type MOS tube is turned off, the power supply current loop is turned off, and the safety protection system is provided.

In one embodiment, the power supply anti-reverse connection circuit further 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.

Specifically, the power supply anti-reverse connection circuit can also be provided with 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 is connected to the second electrode of the DC power supply; based on this, the charging and discharging module can supply power to the system or peripheral circuits based on the DC power supply, and can also supply power to the DC power supply based on the external power supply Charge. Further, the charging and discharging module may further include first electrodes and second electrodes for connecting to an external circuit. In one example, the charging and discharging module further includes a power port for connecting the main power of the system; based on this, the main power of the system can be used as the main power of the system or peripheral circuits, and the DC power can be used as the backup power; the main power of the system can be the system or The peripheral circuit is powered, and the DC power supply can also be charged through the charging and discharging 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, a power port, and the like, which is not specifically limited.

In an example, as shown in Figure 4, V _SYS is used to provide a safe power supply for the subsequent system; the lithium battery power supply is connected, and V2 can be used as a charging and discharging power interface at this time, which can supply voltage to the system, and can also be used as a system The main power supply is the lithium battery charging interface. As long as the upper and lower negatives 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 Pulled high, the NPN transistor Q1 is saturated and turned on, the collector level of Q1 is pulled low, the Vgs of the P-type MOS transistor Q3 is -V _Battery , so Q3 is turned on, the output voltage or input voltage is V2, providing safety for the system The output voltage of the power supply through the lithium battery charging and discharging module is V _SYS , or the total system power supply safely charges the lithium battery through the lithium battery charging and discharging management scheme. However, once the lithium battery is reversely connected, the analysis is as above, the P-type MOS tube is turned off, and the lithium battery charging and discharging circuit is cut off to protect the system and the lithium battery safety. Further, at this time, if the total power supply of the system is connected, the system can still work normally.

Specifically, considering that non-standard factory production or improper use by users will 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 a circuit where the object of anti-reverse connection is a lithium battery. Specifically, VCC is the total power supply of the system, and the lithium battery is used as the auxiliary power supply. When VCC is used as the power supply for the system, the lithium battery can be charged. When the VCC is not connected, the auxiliary power supply lithium battery provides the power supply for the system. When the lithium battery is reversely connected and the VCC is connected, the system will charge the negative electrode of the lithium battery, which will affect the battery life; if the lithium battery is reversely connected and the VCC is not connected, the lithium battery provides energy for the system. Due to the negative voltage connection, the system will be damaged. , causing irreversible damage.

Both the system main power supply and the auxiliary power supply lithium battery can supply power to the system through the charging and discharging module, and the system output power supply has only one V _SYS . The system can work if either the total system power supply or the lithium battery exists. Due to the existence of the anti-reverse connection circuit, even if the lithium battery is reversely connected, the system will not be damaged. If the total power of the system exists at this time, the system can still work normally.

When the lithium battery is connected normally, the inductor L1 suppresses current transients, and the first capacitor C1 suppresses the sudden change of the source voltage of the P-type MOS tube, thereby slowing the impact on the MOS tube when the power is connected, and protecting the MOS tube from damage. The upper and lower sides of the lithium battery are connected to the upper and lower sides. If there is no system power supply VCC connected, the P-type MOS transistor will be turned on due to the existence of its own body diode, which has provided a stable power supply to the system. However, the body diode itself has a large conduction voltage drop and consumes a large amount of power. Then, since the GND level is 0, the base input current of Q2 is 0, as 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, and the collector of Q1 is charged. The level is pulled down, the Vgs of the P-type MOS transistor Q3 is -V _Battery , so Q3 is completely turned on, and the power supplied to the system by the body diode at the moment of access is changed to flow through the low on-resistance MOS tube to output power , thereby providing a safe power supply V _SYS for the system, and at the same time, the power consumption of the MOS tube itself is greatly reduced.

If the total system power VCC is connected, as described above, the Vgs of the P-type MOS transistor Q3 is -V _Battery , Q3 is fully turned on, and the total system power is converted to V2, which can manage and charge the lithium battery. Once the lithium battery is reversely connected, the ground level is pulled high, the positive input voltage is pulled down, the base level of Q2 is pulled up, and the NPN transistor Q2 is turned on. At this time, the base level of Q1 is pulled down, and the NPN type The transistor Q1 is turned off, the collector level of Q1 is pulled high, and the Vgs of the P-type MOS transistor Q3 is V2≥0, so Q3 is turned off, the battery access circuit is turned off, and the lithium battery cannot be charged or discharged. The purpose of anti-reverse connection is to protect the system safely; at this time, the output of the total power supply VCC and V _SYS of the access system is normal, which does not affect the normal operation of the system.

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

DC power supply;

Such as the above-mentioned power supply anti-reverse circuit.

Specifically, the power supply anti-reverse connection circuit connects the two electrodes of the DC power supply. When the DC power supply is reversely connected, the power supply circuit is disconnected in time to protect the power supply and peripheral circuits. The DC power supply can be a one-way power supply or a charging and discharging power supply.

In one example, as shown in FIG. 5 , V1 may be a DC power supply for powering the system, or may be a reserve power supply (lithium battery) of the system. As long as V1 is connected correctly without reverse connection, the base input current of Q2 is 0, as 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, and the collector of Q1 is charged. If the level is pulled down, the Vgs of the P-type MOS transistor Q3 is -V1, so Q3 is turned on; based on this, the two-way charging and discharging of the connected power supply can realize the anti-reverse connection function in the same circuit topology. Once V1 is reversely connected, the ground level is pulled high, the positive input voltage is pulled down, the base level of Q2 is pulled up, and the NPN transistor Q2 is turned on. At this time, the base level of Q1 is pulled down, and the NPN transistor Q1 is turned off, the collector level of Q1 is pulled high, and the Vgs of the P-type MOS transistor Q3 is V2-V1 (V1=0V), so Q3 is turned off, and the power circuit is turned off, so as to achieve the purpose of preventing reverse connection.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the scope of the present application. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the present application should be determined by the appended claims.

Claims (10)

1. A power supply anti-reverse connection circuit is characterized in that, comprising: 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 for connecting to the second electrode of the DC power supply; A switch module includes a first switch tube and a second switch tube; the first pole 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 through a first resistor ; The second pole of the first switch tube is connected to the ground terminal; the first pole of the second switch tube is connected to the control pole of the first switch tube, and is connected to the P-type MOS tube through a second resistor the source electrode of the second switch tube; the second pole of the second switch tube is used to connect the first electrode of the DC power supply; the control pole of the second switch tube is connected to the ground terminal; The switch module turns off the P-type MOS transistor when the 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-type triode or an N-type MOS tube; The second switch tube is an NPN type triode or an N type MOS tube. 3. The power supply anti-reverse connection circuit according to claim 1, characterized in that, further comprising: The current suppression circuit is connected between the drain of the P-type MOS transistor and the first electrode of the DC power supply. 4. The power supply anti-reverse connection circuit according to claim 3, wherein the current suppression circuit comprises 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 connected to the first electrode of the DC power supply. 5. The power supply anti-reverse connection circuit according to claim 1, characterized in that, further comprising: a voltage suppression circuit; the first end of the voltage suppression circuit is connected to the drain of the P-type MOS transistor; the second end of the voltage suppression circuit is connected to the ground terminal. 6. The power supply anti-reverse connection circuit according to claim 5, wherein the voltage suppression circuit comprises a first capacitor; The first terminal of the first capacitor is connected to the drain of the P-type MOS transistor; the second terminal of the first capacitor is connected to the ground terminal. 7. The power supply anti-reverse connection circuit according to any one of claims 1 to 6, characterized in that, further comprising a second capacitor; The first terminal of the second capacitor is connected to the gate of the P-type MOS transistor; the second terminal of the second capacitor is connected to the ground terminal. 8. The power supply anti-reverse connection circuit according to any one of claims 1 to 6, characterized in that, further comprising: a third resistor, connected between the first pole of the first switch tube and the gate of the P-type MOS tube; The fourth resistor is connected between the control electrode of the second switch tube and the ground terminal. 9. The power supply anti-reverse connection circuit according to any one of claims 1 to 6, characterized in that, further comprising 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, comprising: DC power supply; The power supply anti-reverse connection circuit according to any one of claims 1 to 9.

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