Anti-reverse connection and anti-backflow protection circuit for battery charger

By using anti-reverse and anti-backflow protection circuits designed with MOS tubes and RC circuits in the battery charger, the problems of complex and high cost in the existing technology are solved, and the protection effect of low loss and low cost is achieved.

CN223168060UActive Publication Date: 2025-07-29LUOYANG GRASEN POWER TECH CO LTD
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Patent Information

Application Number
CN202422226505.1
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-09-11
Publication Date
2025-07-29
Estimated Expiration
2034-09-11

AI Technical Summary

Technical Problem

The existing battery charger anti-reverse and anti-return protection circuits require the use of a microcontroller or CPU, resulting in complex and costly systems.

Method used

Using the first switching unit, the second switching unit and the control unit, the MOS tube and the RC circuit design prevent the battery energy from being backflowed and reversed, reducing losses and costs.

Benefits of technology

It realizes that while preventing battery energy from being backflowed and reversed, it reduces system losses and costs.

✦ Generated by Eureka AI based on patent content.

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Abstract

According to the anti-reverse-connection and anti-backward-flow protection circuit for the battery charger, a first switch unit is used for preventing backward flow of battery energy, the source electrode of a first MOS tube Q1 of the first switch unit is connected with the output end of the battery charger, and the drain electrode of the first MOS tube Q1 is connected with the positive electrode of a battery through a second switch unit; the grid electrode of the first MOS tube Q1 is used for receiving a first driving signal Drive1; the second switch unit is used for preventing reverse connection of the battery, the drain electrode of a second MOS tube Q2 of the second switch unit is connected with the positive electrode of the battery, and the source electrode of the second MOS tube Q2 is connected with the drain electrode of the first MOS tube Q1; the control unit is used for controlling the on-off of the second switch unit, the drain electrode of a third MOS tube Q3 of the control unit is connected in series with a third resistor R3 and then is connected with the grid electrode of a second MOS tube Q2, and the source electrode of the third MOS tube Q3 is connected with the negative electrode of the battery and the output end of the charger, so that the loss is reduced and the cost is reduced while backward flowing and reverse connection are prevented.
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Description

Technical Field

[0001] The utility model relates to the technical field of battery charger protection, and specifically relates to an anti-reverse connection and anti-backflow protection circuit for a battery charger. Background Art

[0002] Reverse connection of a battery charger can damage the charging circuit and the battery, and even cause an explosion of the battery, leading to more serious situations such as a fire. At the same time, in a circuit with a battery as a load, if there is no anti-backflow circuit, when the input power supply disappears, the battery will supply power to the charging management circuit instead. This not only wastes the battery power in vain, especially for high-current charging devices, but also the battery backflow may cause permanent damage to the charging circuit. Therefore, the anti-backflow protection circuit is also very important in the charging management circuit.

[0003] The common methods for anti-reverse connection and anti-backflow in the prior art are: using a single-chip microcomputer or a CPU and its peripheral circuits to detect whether the battery wiring is correct, and only starting to charge after confirmation. This solution requires the use of a single-chip microcomputer or a CPU, the system is complex, and for a charging system that originally does not have a single-chip microcomputer or a CPU, these components need to be added additionally, resulting in high costs. Content of the Utility Model

[0004] In order to solve the deficiencies of the prior art, the utility model provides an anti-reverse connection and anti-backflow protection circuit for a battery charger, which reduces the loss and cost while preventing reverse connection and backflow of the battery charger.

[0005] The technical solution adopted by the utility model to solve the above technical problems is: an anti-reverse connection and anti-backflow protection circuit for a battery charger, including a first switch unit, a second switch unit, and a control unit;

[0006] The first switch unit is used to prevent the backflow of battery energy. The first switch unit includes a first MOS transistor Q1 driven by a first driving signal Drive1. The source electrode of the first MOS transistor Q1 is connected to the output terminal of the battery charger. The drain electrode of the first MOS transistor Q1 is connected to the positive electrode of the battery through the second switch unit. The gate electrode of the first MOS transistor Q1 is used to receive the first driving signal Drive1. The second switch unit is used to prevent reverse connection of the battery. The second switch unit includes a second MOS transistor Q2. The drain electrode of the second MOS transistor Q2 is connected to the positive electrode of the battery. The source electrode of the second MOS transistor Q2 is connected to the drain electrode of the first MOS transistor Q1;

[0007] A control unit for controlling the on / off of the second switching unit. The control unit includes a third MOS transistor Q3 and a second drive signal Drive2 for controlling the on / off of the third MOS transistor Q3. The drain of the third MOS transistor Q3 is connected to the gate of the second MOS transistor Q2, and the source of the third MOS transistor Q3 is connected to both the negative electrode of the battery and the charger output terminal.

[0008] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The first MOS transistor Q1 is connected with a first RC circuit. The first RC circuit includes a first resistor R1 and a first capacitor C1 connected in series. One end of the first RC circuit is connected to the gate of the first MOS transistor Q1, and the other end is connected to the drain of the first MOS transistor Q1.

[0009] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The first MOS transistor Q1 is set as an N-channel MOS transistor.

[0010] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The second MOS transistor Q2 is connected with an RD circuit. The RD circuit includes a second resistor R2 and a diode D1 connected in parallel. One end of the RD circuit is connected to the gate of the second MOS transistor Q2, and the other end is connected to the source of the second MOS transistor Q2.

[0011] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The diode D1 is set as a zener diode.

[0012] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The second MOS transistor Q2 is set as a P-channel MOS transistor.

[0013] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The third MOS transistor Q3 is connected with a current-limiting resistor R3.

[0014] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The third MOS transistor Q3 is connected with a second RC circuit. The second RC circuit includes a second capacitor C2 and a fourth resistor R4 connected in parallel. One end of the second RC circuit is connected to the gate of the third MOS transistor Q3, and the other end is respectively connected to the source of the third MOS transistor Q3, the negative electrode of the battery, and the charger output terminal.

[0015] As a further optimization of a reverse connection prevention and reverse charging prevention protection circuit for a battery charger in the utility model: The third MOS transistor Q3 is set as an N-channel MOS transistor.

[0016] Beneficial effects: The first switch unit of the present utility model includes a first MOS transistor Q1 driven by a first drive signal Drive1. The source of the first MOS transistor Q1 is connected to the output terminal of the battery charger. The drain of the first MOS transistor Q1 is connected to the positive electrode of the battery through a second switch unit. The gate of the first MOS transistor Q1 is used to receive the first drive signal Drive1. The first switch unit is used to prevent the reverse flow of battery energy;

[0017] The second switch unit includes a second MOS transistor Q2. The drain of the second MOS transistor Q2 is connected to the positive electrode of the battery. The source of the second MOS transistor Q2 is connected to the drain of the first MOS transistor Q1. The second switch unit is used to prevent the reverse connection of the battery;

[0018] The control unit includes a third MOS transistor Q3 and a second drive signal Drive2 for controlling the on / off of the third MOS transistor Q3. The drain of the third MOS transistor Q3 is connected to the gate of the second MOS transistor Q2 after being connected in series with a third resistor R3. The source of the third MOS transistor Q3 is connected to both the negative electrode of the battery and the output terminal of the charger. The control unit is used to control the on / off of the second switch unit. The present utility model reduces losses and costs while preventing reverse flow and reverse connection. Description of the Drawings

[0019] Figure 1 is the structural schematic diagram of the present utility model;

[0020] Figure 2 is the schematic diagram of the reverse connection of the battery of the present utility model. Detailed Embodiments

[0021] The following further elaborates on the technical solution of the present utility model in combination with specific embodiments. For parts not detailedly recorded and disclosed in the following embodiments of the present utility model, they should all be understood as the existing technologies known or should be known to those skilled in the art, such as the models of N-channel MOS transistors and P-channel MOS transistors, the model of the battery, the model of the charger, the model of the first resistor R1, the model of the first capacitor C1, the current-limiting resistor R3, the zener diode, etc.

[0022] An anti-reverse connection and anti-reverse flow protection circuit for a battery charger, as Figure 1As shown in the figure, it includes a first switch unit, a second switch unit and a control unit. The first switch unit is used to prevent the reverse flow of battery energy. The first switch unit includes a first MOS transistor Q1 driven by a first drive signal Drive1. The first MOS transistor Q1 is set as an N-channel MOS transistor. The body diode of the first MOS transistor Q1 is used to oppose the battery terminal voltage, which can prevent the reverse flow of battery energy into the power supply. The source of the first MOS transistor Q1 is connected to the output terminal of the battery charger. The drain of the first MOS transistor Q1 is connected to the positive electrode of the battery through the second switch unit. The gate of the first MOS transistor Q1 is used to receive the first drive signal Drive1. The first drive signal Drive1 is used to control the turn-on and turn-off of the first MOS transistor Q1. In the power-on output state, the first drive signal Drive1 is set high, and the first MOS transistor Q1 conducts. The voltage drop is Rdson, and its conduction loss is low, reducing heat generation and improving efficiency. In the power-off stop output state, Drive1 is set low, and the first MOS transistor Q1 turns off, playing the function of its body diode to prevent the reverse flow of battery energy. The first MOS transistor Q1 is connected to a first RC circuit. The first RC circuit includes a series-connected first resistor R1 and a first capacitor C1. One end of the first RC circuit is connected to the gate of the first MOS transistor Q1, and the other end is connected to the drain of the first MOS transistor Q1. It can control the turn-on speed of the first MOS transistor Q1 to achieve soft start, reduce current surges, and can also limit the rise of the drain voltage of the first MOS transistor Q1 to avoid damage to the first MOS transistor Q1 due to voltage overshoot, improving the reliability of the anti-reverse flow circuit.

[0023] The second switch unit is used to prevent the battery from being reversely connected. The second switch unit includes a second MOS transistor Q2. The second MOS transistor Q2 is set as a P-channel MOS transistor. The drain of the second MOS transistor Q2 is connected to the positive electrode of the battery. The source of the second MOS transistor Q2 is connected to the drain of the first MOS transistor Q1. The second MOS transistor Q2 is connected to an RD circuit. When the charger outputs normally and the battery is connected correctly, such as Figure 1As shown, the second MOS transistor Q2 is controlled by a control circuit composed of the third MOS transistor Q3 to conduct, and the current flows from S to D, and the charger charges the battery in the forward direction. The RD circuit includes a second resistor R2 and a diode D1 connected in parallel. The diode D1 is set as a zener diode. One end of the RD circuit is connected to the gate of the second MOS transistor Q2, and the other end is connected to the source of the second MOS transistor Q2. The diode D1 and the second resistor R2 can prevent the Vgs of the second MOS transistor Q2 from being too large, resulting in the breakdown of the second MOS transistor Q2, and improving the reliability of the second switching unit. The body diode of the second MOS transistor Q2 can cut off the current loop in the case of battery reverse connection to prevent the battery terminal from being short-circuited and burned; in the case of the power supply being shut down and the output stopped, if the battery is reverse-connected, the body diode of the second MOS transistor Q2 will reverse-bias, and the battery will be normal; if the battery is reverse-connected and the power supply is turned on and outputs, even if the control circuit composed of the third MOS transistor Q3 is in the on state, since the second MOS transistor Q2 is a P-channel MOS transistor, the voltage of the gate cannot be set low due to the reverse connection of the battery, so the second MOS transistor Q2 cannot conduct, and the current cannot form a loop, and the battery is prevented from being burned.

[0024] A control unit is used to control the on / off of the second switching unit. The control unit includes a third MOS transistor Q3 and a second drive signal Drive2 for controlling the on / off of the third MOS transistor Q3. The third MOS transistor Q3 is set as an N-channel MOS transistor. The drain of the third MOS transistor Q3 is connected to the gate of the second MOS transistor Q2. The source of the third MOS transistor Q3 is connected to both the negative electrode of the battery and the charger output terminal. The third MOS transistor Q3 is connected with a current-limiting resistor R3. The third MOS transistor Q3 is connected with a second RC circuit. The second RC circuit includes a second capacitor C2 and a fourth resistor R4 connected in parallel. One end of the second RC circuit is connected to the gate of the third MOS transistor Q3, and the other end is respectively connected to the source of the third MOS transistor Q3, the negative electrode of the battery, and the charger output terminal to control the switching speed, suppress the surge voltage, enhance the anti-interference ability of the switch, and improve the reliability of the entire control circuit. The control circuit composed of the third MOS transistor Q3 and the second drive signal Drive2 can control the on and off of the anti-reverse connection circuit. When the charger normally outputs to charge the battery, the second drive signal Drive2 is set to a high level, and the third MOS transistor Q3 conducts, which will pull down the gate voltage of the second MOS transistor Q2 of the anti-reverse connection circuit, so that it conducts, and the current flows from the source to the drain of the second MOS transistor Q2, thereby charging the battery; the current-limiting resistor R3 reduces Ids and protects the third MOS transistor Q3; as Figure 2 As shown, in the case of battery reverse connection, the battery voltage will also pull up the gate of the second MOS transistor Q2 through the body diode of the third MOS transistor Q3, and is not controlled by the second drive signal Drive2, so that the second MOS transistor Q2 cannot conduct either, and the battery current cannot form a loop, avoiding damage to the power supply and burning of the battery.

[0025] The utility model can be used in cooperation with an in-vehicle energy storage battery of an automobile or an energy storage battery of a charging station. The above description of the disclosed embodiments enables those skilled in the art to implement or use the utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the utility model. Therefore, the utility model will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An anti-reverse connection and anti-backflow protection circuit for a battery charger, characterized in that: It includes a first switching unit, a second switching unit and a control unit; The first switching unit is used to prevent the reverse flow of battery energy. The first switching unit includes a first MOS transistor Q1 driven by a first driving signal Drive1. The source of the first MOS transistor Q1 is connected to the output terminal of the battery charger. The drain of the first MOS transistor Q1 is connected to the positive electrode of the battery through the second switching unit. The gate of the first MOS transistor Q1 is used to receive the first driving signal Drive1; The second switching unit is used to prevent the reverse connection of the battery. The second switching unit includes a second MOS transistor Q2. The drain of the second MOS transistor Q2 is connected to the positive electrode of the battery. The source of the second MOS transistor Q2 is connected to the drain of the first MOS transistor Q1; The control unit is used to control the on-off of the second switching unit. The control unit includes a third MOS transistor Q3 and a second driving signal Drive2 for controlling the on-off of the third MOS transistor Q3. The drain of the third MOS transistor Q3 is connected to the gate of the second MOS transistor Q2. The source of the third MOS transistor Q3 is connected to both the negative electrode of the battery and the output terminal of the charger.

2. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 1, characterized in that: The first MOS transistor Q1 is connected with a first RC circuit. The first RC circuit includes a first resistor R1 and a first capacitor C1 connected in series. One end of the first RC circuit is connected to the gate of the first MOS transistor Q1, and the other end is connected to the drain of the first MOS transistor Q1.

3. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 2, characterized in that: The first MOS transistor Q1 is set as an N-channel MOS transistor.

4. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 1, characterized in that: The second MOS transistor Q2 is connected with an RD circuit. The RD circuit includes a second resistor R2 and a diode D1 connected in parallel. One end of the RD circuit is connected to the gate of the second MOS transistor Q2, and the other end is connected to the source of the second MOS transistor Q2.

5. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 4, characterized in that: The diode D1 is set as a zener diode.

6. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 1, characterized in that: The second MOS transistor Q2 is set as a P-channel MOS transistor.

7. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 1, characterized in that: The third MOS transistor Q3 is connected with a current-limiting resistor R3.

8. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 1, characterized in that: The third MOS transistor Q3 is connected with a second RC circuit. The second RC circuit includes a second capacitor C2 and a fourth resistor R4 connected in parallel. One end of the second RC circuit is connected to the gate of the third MOS transistor Q3, and the other end is respectively connected to the source of the third MOS transistor Q3, the negative electrode of the battery and the output terminal of the charger.

9. The reverse connection prevention and backflow prevention protection circuit for a battery charger according to claim 1, characterized in that: The third MOS transistor Q3 is set as an N-channel MOS transistor.