Anti-current backflow circuit, cigarette lighter and energy storage power supply

Abstract

The embodiment of the present application discloses a current reverse flow prevention circuit. The current reverse flow prevention circuit comprises a current detection module, a control module, a voltage reduction enable module and a switch switching module. The control module outputs a first type of level signal when the target current is a negative current. The voltage reduction enable module controls the voltage reduction circuit to enter a non-working state in response to the first type of level signal. The switch switching module disconnects the current loop to block the current reverse flow of the load back to the voltage reduction circuit in response to the first type of level signal. The embodiment of the present application automatically detects whether the load reverses the target current back to the voltage reduction circuit. In the case that the load reverses the target current back to the voltage reduction circuit, the current loop of the reversed target current is automatically disconnected, the reversed target current output by the load is prevented from flowing back to the voltage reduction circuit, and thus the working reliability of the voltage reduction circuit is improved and the voltage reduction circuit is prevented from being damaged.

Description

Technical Field

[0001] This application relates to the field of backflow prevention technology, specifically to a backflow prevention circuit, a cigarette lighter, and an energy storage power supply. Background Technology

[0002] Energy storage devices are equipped with a cigarette lighter, which converts the stored energy voltage output by the device into a driving voltage. This driving voltage is then transmitted to the load through the cigarette lighter's output port to power the load. In practical applications, users often mistakenly use the cigarette lighter's output port as an input port, plugging power devices into the output port. This causes the power device's current to flow back into the energy storage device, which can easily damage the energy storage device or cause a safety accident. Summary of the Invention

[0003] To address the aforementioned technical problems, embodiments of this application provide an anti-current backflow circuit, a cigarette lighter, and an energy storage power supply, thereby improving the current backflow situation present in related technologies.

[0004] In a first aspect, embodiments of this application provide an anti-current backflow circuit, including a current detection module, a control module, a buck enable module, and a switch switching module. The current detection module is disposed on a preset current loop between the buck circuit and the load, and is configured to detect a target current flowing through the current loop. The control module is connected to the current detection module and is configured to output a first-level signal when the target current is a negative current, and output a second-level signal when the target current is a positive current. The buck enable module is electrically connected to both the control module and the buck circuit, and is configured to control the buck circuit to enter a non-operating state in response to the first-level signal, or to control the buck circuit to enter an operating state in response to the second-level signal. The switch switching module is disposed on the current loop between the buck circuit and the load and is electrically connected to the control module. It is configured to disconnect the current loop in response to the first-level signal to prevent current from the load from flowing back into the buck circuit, or to connect the current loop in response to the second-level signal, so that the buck circuit provides the target current to the load through the current loop.

[0005] Optionally, the buck enable module includes an enable unit and a first trigger unit. The enable unit is electrically connected to the buck circuit and is also subjected to a preset battery voltage. The first trigger unit is electrically connected to both the enable unit and the control module, and is configured to, in response to a first type of level signal, control the enable unit to output a first enable signal to the buck circuit, so that the buck circuit enters a non-operating state based on the first enable signal; or, in response to a second type of level signal, control the enable unit to output a second enable signal to the buck circuit under the action of the battery voltage, so that the buck circuit enters an operating state based on the second enable signal.

[0006] Optionally, the enabling unit includes a first current-limiting voltage divider circuit and a first switching circuit. The first current-limiting voltage divider circuit is electrically connected to the buck circuit. The first switching circuit is electrically connected to the first trigger unit and the first current-limiting voltage divider circuit, and is also applied with the battery voltage. It is configured to respond to a third-level signal output by the first trigger unit, output a first enabling signal to the buck circuit through the first current-limiting voltage divider circuit, so that the buck circuit enters a non-operating state based on the first enabling signal; or, respond to a fourth-level signal output by the first trigger unit, output a second enabling signal to the buck circuit through the first current-limiting voltage divider circuit, so that the buck circuit enters a non-operating state based on the second enabling signal.

[0007] Optionally, the first triggering unit includes a second current-limiting voltage divider circuit and a second switching circuit. The second current-limiting voltage divider circuit is electrically connected to the enabling unit. The second switching circuit is electrically connected to both the second current-limiting voltage divider circuit and the control module, and is configured to respond to a first-level signal output by the control module, by controlling the enabling unit to output a first enabling signal to the buck circuit through the second current-limiting voltage divider circuit, so that the buck circuit enters a non-operating state based on the first enabling signal. Alternatively, in response to a second-level signal output by the control module, the enabling unit is controlled by the second current-limiting voltage divider circuit to output a second enabling signal to the buck circuit under the influence of the battery voltage, so that the buck circuit enters an operating state based on the second enabling signal.

[0008] Optionally, the switching module includes a switching unit and a second triggering unit. The switching unit is disposed on the current loop between the step-down circuit and the load. The second triggering unit is electrically connected to the switching unit and the control module respectively, and is configured to, in response to the first type of level signal, control the switching unit to disconnect the current loop to prevent the current from flowing back into the step-down circuit from the load, or, in response to the second type of level signal, connect the current loop so that the step-down circuit provides the target current to the load through the current loop.

[0009] Optionally, the switching unit includes a first NMOS transistor, a first resistor, a second resistor, and a first PNP transistor. The first NMOS transistor is disposed in the current loop between the step-down circuit and the load, and the gate of the first NMOS transistor is electrically connected to the first end of the first resistor and the first end of the second resistor, respectively. The second end of the first resistor is grounded, and the second end of the second resistor is electrically connected to the collector of the first PNP transistor. A preset battery voltage is applied to the emitter of the first PNP transistor, and the base of the first PNP transistor is electrically connected to the second trigger unit.

[0010] The first PNP transistor is configured to, in response to a fifth-level signal output by the second trigger unit, control the first NMOS transistor to disconnect the current loop to prevent the current from the load from flowing back into the buck circuit, or, in response to a sixth-level signal output by the second trigger unit, control the first NMOS transistor to connect the current loop so that the buck circuit provides the target current to the load through the current loop.

[0011] Optionally, the second trigger unit includes a third resistor, a fourth resistor, and a first NPN transistor. The first end of the third resistor is electrically connected to the switching unit, the second end of the third resistor is electrically connected to the collector of the first NPN transistor, the emitter of the first NPN transistor is grounded, the base of the first NPN transistor is electrically connected to the first end of the fourth resistor, and the second end of the fourth resistor is electrically connected to the control module.

[0012] The first NPN transistor is configured to, in response to a first type of level signal transmitted by the control module through the fourth resistor, control the switching unit to disconnect the current loop to prevent the current from flowing back into the buck circuit from the load, or, in response to a second type of level signal transmitted by the control module through the fourth resistor, connect the current loop so that the buck circuit provides the target current to the load through the current loop.

[0013] Optionally, the control module includes a first controller and a second controller. The first controller is electrically connected to the buck enable module, the switch module, and the current detection module, respectively, and is configured to output a first-level signal when the target current is a negative current, and to output a second-level signal when the target current is a positive current. The second controller is electrically connected to the buck enable module and the buck circuit, respectively, and is configured to control the buck circuit to enter a non-operating state in response to a first enable signal output by the buck enable module, or to control the buck circuit to enter an operating state in response to a second enable signal output by the buck enable module.

[0014] In a second aspect, embodiments of this application provide a cigarette lighter, including: a step-down circuit and the aforementioned anti-current backflow circuit, wherein the switching module and the current detection module of the anti-current backflow circuit are both disposed in the current loop between the step-down circuit and the load.

[0015] In a third aspect, embodiments of this application provide an energy storage power source, including the cigarette lighter described above.

[0016] The beneficial effects of the anti-current backflow circuit provided in this application embodiment are as follows: This application embodiment automatically detects whether the load is flowing the target current back into the buck circuit. When the load is flowing the target current back into the buck circuit, it automatically disconnects the current loop of the flowing target current, preventing the target current output by the load from flowing back into the buck circuit. This improves the operational reliability of the buck circuit and avoids damage to it. Simultaneously, when the buck circuit is normally outputting the target current to the load, this application embodiment can maintain the buck circuit's ability to output the target current to the load. Therefore, the anti-current backflow circuit provided in this application embodiment can automatically switch between normal current output and current backflow conditions, ensuring that the current cannot flow back into the buck circuit and also ensuring the normal operation of the buck circuit. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 A schematic diagram of the circuit structure of a cigarette lighter provided for related technologies; Figure 2 A schematic diagram of the circuit structure of an energy storage power supply provided in an embodiment of this application; Figure 3 for Figure 2 The circuit diagram of the cigarette lighter is shown below; Figure 4 A schematic diagram of the circuit structure for an anti-current backflow circuit provided in an embodiment of this application; Figure 5 A schematic diagram of a circuit structure for an anti-current backflow circuit provided in another embodiment of this application; Figure 6 A schematic diagram of the circuit structure for an anti-current backflow circuit provided in another embodiment of this application; Figure 7 A schematic diagram of the circuit structure for an anti-current backflow circuit provided in another embodiment of this application; Figure 8A schematic diagram of the circuit structure for an anti-current backflow circuit provided in another embodiment of this application; Figure 9 A schematic diagram of the circuit structure for an anti-current backflow circuit provided in another embodiment of this application; Figure 10 This is a schematic diagram of the circuit structure of an anti-current backflow circuit provided in another embodiment of this application. Detailed Implementation

[0019] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "electrically connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. Furthermore, technical features involved in the different embodiments of this application described below may be combined with each other as long as they do not conflict with each other.

[0021] In the process of implementing the embodiments of this application, the inventors discovered the following problems with the cigarette lighters provided by related technologies, as follows: Please see Figure 1The cigarette lighter provided by the related technology is a buck circuit. The cigarette lighter includes MOSFETs K1, K2, and K3, an inductor K4, capacitors K5 and K6, and resistors K7 and K8. When the output port of the cigarette lighter is mistakenly used as an input port, the output port VOUT is connected to the power supply. The voltage from the power supply is applied to node BAT_BMS through the body diode of MOSFET K2. The voltage at node BAT_BMS, under the voltage division effect of resistors K7 and K8, outputs a high level through node EN. The Buck controller detects this high level and enters the working state.

[0022] When the voltage input to the output port VOUT of the power supply is less than the set output voltage of the cigarette lighter, the Buck controller controls the operating state of MOSFETs K2 and K3 in boost mode, causing MOSFETs K2 and K3, along with inductor K4, to form a boost circuit. This boost circuit uses the output port VOUT as input and node BAT_BMS as output. The voltage at node BAT_BMS charges the battery BAT+ through the body diode of MOSFET K1, meaning the power supply's current flows back into the battery. When the voltage connected to the output port VOUT is greater than the sum of the battery BAT+ voltage and the voltage drop across the body diode of MOSFET K1, the power supply will also charge the battery BAT+, again resulting in current backflow. Therefore, regardless of the power supply's voltage, when the cigarette lighter's output port is mistakenly used as an input port, the power supply's voltage will flow back into the battery to charge it. This charging method can easily damage the battery or cause safety accidents.

[0023] The following embodiments of this application provide an energy storage power supply, which can be a portable energy storage power supply or a stationary energy storage power supply. Please refer to... Figure 2 The energy storage power supply 100 includes a battery 200 and a cigarette lighter 300. The battery 200 is electrically connected to the cigarette lighter 300, and the output port VOUT of the cigarette lighter 300 is electrically connected to the load 101. The battery 200 provides voltage BAT+ to the cigarette lighter 300. The cigarette lighter 300 uses a step-down operating mode to step down the voltage BAT+ to obtain a stepped-down voltage, which is then transmitted to the load 101 through the output port VOUT to drive the load 101.

[0024] Please see Figure 3 The cigarette lighter 300 includes a step-down circuit 400 and an anti-current backflow circuit 500. The anti-current backflow circuit 500 is electrically connected to the step-down circuit 400 and is used to prevent the current from the load 101 from flowing back into the step-down circuit 400.

[0025] Please see Figure 4The anti-current backflow circuit 500 includes a current detection module 600, a control module 700, a step-down enable module 800, and a switch switching module 900.

[0026] A current detection module 600 is installed in the preset current loop between the step-down circuit 400 and the load 101 to detect the target current flowing through the current loop. The current loop is the loop through which the step-down circuit 400 can transmit current to the load 101. The target current can be a positive current or a negative current. The negative current is the current transmitted from the load 101 to the step-down circuit 400, and the positive current is the current transmitted from the step-down circuit 400 to the load 101. The direction of the positive current is opposite to the direction of the negative current.

[0027] It is understandable that the current detection module 600 can be a current sensor or a current sampling circuit, etc.

[0028] The control module 700 is connected to the current detection module 600 and is used to output a first-type level signal when the target current is a negative current and a second-type level signal when the target current is a positive current.

[0029] The level type of the first type of signal is the opposite of that of the second type of signal. In some embodiments, the first type of signal is high and the second type of signal is low. In other embodiments, the first type of signal is low and the second type of signal is high.

[0030] The buck enable module 800 is electrically connected to both the control module 700 and the buck circuit 400. In response to a first-type voltage level signal, it controls the buck circuit 400 to enter a non-operating state. When the buck circuit 400 enters the non-operating state, it stops outputting power to the load 101. The buck enable module 800 also controls the buck circuit 400 to enter an operating state in response to a second-type voltage level signal. When the buck circuit 400 enters the operating state, it outputs power to the load 101.

[0031] The switch switching module 900 is located in the current loop between the step-down circuit 400 and the load 101 and is electrically connected to the control module 700. It is used to disconnect the current loop in response to a first-level signal to prevent the current from the load 101 from flowing back into the step-down circuit 400. Therefore, in this embodiment of the application, when the target current output by the load 101 flows back into the step-down circuit 400, the switch switching module 900 is driven by the first-level signal to disconnect the current loop, so that the target current cannot flow back into the step-down circuit 400. This can avoid damage to the step-down circuit 400 or avoid safety accidents, thereby improving the reliability and safety of the cigarette lighter.

[0032] The switch module 900 is also used to respond to the second type of level signal by connecting the current loop, so that the step-down circuit 400 provides the target current to the load 101 through the current loop. In this embodiment, when the target current is a positive current, the step-down circuit 400 is controlled to normally provide the target current to the load 101, ensuring that the cigarette lighter can normally drive the load 101 to work.

[0033] This embodiment of the application automatically detects whether the load 101 is supplying the target current to the buck circuit 400. If the load 101 is supplying the target current to the buck circuit 400, the current loop of the supplying target current is automatically disconnected, preventing the target current output by the load 101 from flowing back into the buck circuit 400. This improves the operational reliability of the buck circuit 400 and prevents damage to it. Simultaneously, when the buck circuit 400 is normally supplying the target current to the load 101, this embodiment of the application can maintain the buck circuit 400's ability to supply the target current to the load 101. Therefore, the anti-current-backflow circuit 500 provided in this embodiment of the application can automatically switch between normal current output and current-backflow conditions, ensuring that current cannot flow back into the buck circuit 400, while also ensuring the normal operation of the buck circuit 400.

[0034] It is understood that the control module 700 can be a single controller or it can consist of two controllers. Please refer to [link / reference]. Figure 5 The control module 700 includes a first controller 71 and a second controller 72.

[0035] The first controller 71 is electrically connected to the buck enable module 800, the switch switching module 900, and the current detection module 600, respectively, and is used to output a first-type level signal when the target current is a negative current and to output a second-type level signal when the target current is a positive current.

[0036] The second controller 72 is electrically connected to the buck enable module 800 and the buck circuit 400 respectively. It is used to control the buck circuit 400 to enter the non-working state in response to the first enable signal output by the buck enable module 800, or to control the buck circuit 400 to enter the working state in response to the second enable signal output by the buck enable module 800.

[0037] The level type of the first enable signal is opposite to that of the second enable signal. In some embodiments, the first enable signal is high and the second enable signal is low. In other embodiments, the first enable signal is low and the second enable signal is high.

[0038] In this embodiment, the control module 700 is configured as a dual-controller architecture. The first controller 71 outputs a corresponding level signal based on the current direction of the target current, and the second controller 72 controls the buck circuit 400 separately. The buck circuit 400 has high real-time and accuracy requirements. The separate second controller 72 is used to meet the control requirements of the buck circuit 400, which helps to meet the requirements of high real-time and high accuracy.

[0039] Please see Figure 6 The step-down enable module 800 includes an enable unit 81 and a first trigger unit 82.

[0040] The enable unit 81 is electrically connected to the buck circuit 400 and is also subject to a preset battery voltage BAT_BMS.

[0041] The first trigger unit 82 is electrically connected to the enable unit 81 and the control module 700 respectively. It is used to control the enable unit 81 to output a first enable signal to the buck circuit 400 in response to a first type of level signal, so that the buck circuit 400 enters a non-working state based on the first enable signal. Alternatively, in response to a second type of level signal, it controls the enable unit 81 to output a second enable signal to the buck circuit 400 under the action of the battery voltage BAT_BMS, so that the buck circuit 400 enters a working state based on the second enable signal.

[0042] In this embodiment, when the target current is negative, not only is the current loop of the target current flowing back to the buck circuit 400 disconnected, but also a first enable signal is output to the buck circuit 400 via the enable unit 81 to trigger the buck circuit 400 to stop working, thus preventing the buck circuit 400 from operating under abnormal current conditions and easily causing safety accidents or damage to the buck circuit 400. Simultaneously, in this embodiment, when the target current is positive, a second enable signal is output to the buck circuit 400 via the enable unit 81 to trigger the buck circuit 400 to enter the working state, thereby ensuring that the buck circuit 400 operates reliably under normal current conditions.

[0043] Please see Figure 7 The enabling unit 81 includes a first current-limiting voltage divider circuit 811 and a first switching circuit 812. The first current-limiting voltage divider circuit 811 is electrically connected to the buck circuit 400. The first switching circuit 812 is electrically connected to the first trigger unit 82 and the first current-limiting voltage divider circuit 811, and is also supplied with battery voltage BAT_BMS.

[0044] The first switching circuit 812 is used to respond to the third type level signal output by the first trigger unit 82, and output a first enable signal to the buck circuit 400 through the first current limiting voltage divider circuit 811, so that the buck circuit 400 enters a non-working state based on the first enable signal.

[0045] The third type of level signal is the level signal generated by the first trigger unit 82 when triggered by the first type of level signal. It can be understood that the third type of level signal can be high or low, and the level type of the third type of level signal is constrained by the circuit structure of the first switching circuit 812.

[0046] The first switching circuit 812 is also used to respond to the fourth type of level signal output by the first trigger unit 82, and output a second enable signal to the buck circuit 400 through the first current limiting voltage divider circuit 811, so that the buck circuit 400 enters a non-working state based on the second enable signal.

[0047] The fourth type of level signal is the level signal generated by the first trigger unit 82 when triggered by the second type of level signal. The level type of the third type of level signal is the opposite of that of the fourth type of level signal. In some embodiments, the third type of level signal is high and the fourth type of level signal is low. In other embodiments, the third type of level signal is low and the fourth type of level signal is high.

[0048] Please see Figure 8 The first triggering unit 82 includes a second current-limiting voltage divider circuit 821 and a second switching circuit 822. The second current-limiting voltage divider circuit 821 is electrically connected to the enabling unit 81, and the second switching circuit 822 is electrically connected to the second current-limiting voltage divider circuit 821 and the control module 700, respectively. For example, the second switching circuit 822 is electrically connected to the second current-limiting voltage divider circuit 821 and the first controller 71, respectively.

[0049] The second switching circuit 822 is used to respond to the first type of level signal output by the control module 700, and control the enable unit 81 to output a first enable signal to the buck circuit 400 through the second current limiting voltage divider circuit 821, so that the buck circuit 400 enters a non-working state based on the first enable signal.

[0050] The second switching circuit 822 is also used to respond to the second type of level signal output by the control module 700, and control the enable unit 81 to output a second enable signal to the buck circuit 400 under the action of the battery voltage through the second current limiting voltage divider circuit 821, so that the buck circuit 400 enters the working state based on the second enable signal.

[0051] This embodiment uses a second current-limiting voltage divider circuit 821 to divide the battery voltage, reducing the current stress exerted on the second switching circuit 822 by the battery voltage and improving the service life of the second switching circuit 822. Simultaneously, this embodiment indirectly controls the enable unit 81 to output a corresponding enable signal to the buck circuit 400 through the second switching circuit 822, preventing a large battery voltage from being directly applied to the second switching circuit 822, thus achieving the goal of controlling a large voltage with a small voltage.

[0052] Please see Figure 9 The switch switching module 900 includes a switch unit 91 and a second trigger unit 92. The switch unit 91 is disposed in the current loop between the step-down circuit 400 and the load 101. The second trigger unit 92 is electrically connected to both the switch unit 91 and the control module 700.

[0053] The second trigger unit 92 is used to control the switch unit 91 to disconnect the current loop in response to the first type of level signal, so as to prevent the current of the load 101 from flowing back into the buck circuit 400. The second trigger unit 92 is also used to connect the current loop in response to the second type of level signal, so that the buck circuit 400 provides the target current to the load 101 through the current loop.

[0054] In this embodiment, the second trigger unit 92 controls the switching state of the switch unit 91, ensuring flexible and precise switching between normal current output and current backflow. This ensures that the current cannot flow back into the step-down circuit 400, while also ensuring that the step-down circuit 400 works normally.

[0055] Please see Figure 10 The switching unit 91 includes a first NMOS transistor Q1, a first resistor R1, a second resistor R2, and a first PNP transistor Q2. The first NMOS transistor Q1 is disposed in the current loop between the step-down circuit 400 and the load 101. The gate of the first NMOS transistor Q1 is electrically connected to the first terminal of the first resistor R1 and the first terminal of the second resistor R2, respectively. The second terminal of the first resistor R1 is grounded. The second terminal of the second resistor R2 is electrically connected to the collector of the first PNP transistor Q2. A preset battery voltage is applied to the emitter of the first PNP transistor Q2. The base of the first PNP transistor Q2 is electrically connected to the second trigger unit 92.

[0056] The first PNP transistor Q2 is used in response to the fifth-level signal output by the second trigger unit 92 to control the first NMOS transistor Q1 to disconnect the current loop, thereby preventing the current from the load 101 from flowing back into the buck circuit 400. The fifth-level signal is a level signal generated by the second trigger unit 92 when triggered by the first-level signal.

[0057] The first PNP transistor Q2 is also used to control the first NMOS transistor Q1 to connect the current loop in response to the sixth-level signal output by the second trigger unit 92, so that the buck circuit 400 provides the target current to the load 101 through the current loop. The sixth-level signal is the level signal generated by the second trigger unit 92 when triggered by the second-level signal.

[0058] The level type of the fifth level signal is the opposite of that of the sixth level signal. In some embodiments, the fifth level signal is high and the sixth level signal is low. In other embodiments, the fifth level signal is low and the sixth level signal is high.

[0059] Please continue reading. Figure 10 The second trigger unit 92 includes a third resistor R3, a fourth resistor R4, and a first NPN transistor Q3. The first end of the third resistor R3 is electrically connected to the switching unit 91, the second end of the third resistor R3 is electrically connected to the collector of the first NPN transistor Q3, the emitter of the first NPN transistor Q3 is grounded, the base of the first NPN transistor Q3 is electrically connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is electrically connected to the control module 700.

[0060] The first NPN transistor Q3 is used to respond to the first type of level signal transmitted by the control module 700 through the fourth resistor R4, and to control the switching unit 91 to disconnect the current loop to prevent the current of the load 101 from flowing back into the buck circuit 400.

[0061] The first NPN transistor Q3 is also used to connect the current loop in response to the second type of level signal transmitted by the control module 700 through the fourth resistor R4, so that the buck circuit 400 provides the target current to the load 101 through the current loop.

[0062] Please continue reading. Figure 10 The first current-limiting voltage divider circuit 811 includes a fifth resistor R5, and the first switching circuit 812 includes a second NPN transistor Q4 and a sixth resistor R6. The first end of the sixth resistor R6 is electrically connected to the control module 700, the second end of the sixth resistor R6 is electrically connected to the base of the second NPN transistor Q4, the emitter of the second NPN transistor Q4 is grounded, the collector of the second NPN transistor Q4 is electrically connected to the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is electrically connected to the first trigger unit 82.

[0063] Please continue reading. Figure 10 The second current-limiting voltage divider circuit 821 includes a seventh resistor R7 and an eighth resistor R8. The second switching circuit 822 includes a second PNP transistor Q5. The base of the second PNP transistor Q5 is electrically connected to the second terminal of the fifth resistor R5. The emitter of the second PNP transistor Q5 is supplied with the battery voltage BAT_BMS. The collector of the second PNP transistor Q5 is electrically connected to the first terminal of the seventh resistor R7. The second terminal of the seventh resistor R7 and the first terminal of the eighth resistor R8 are both electrically connected to the control module 700. The second terminal of the eighth resistor R8 is grounded.

[0064] Please continue reading. Figure 10The current detection module 600 includes a ninth resistor R9, which is set in the current loop and both ends of the ninth resistor R9 are electrically connected to the control module 700.

[0065] Please continue reading. Figure 10 The step-down circuit 400 includes a MOSFET Q6, a second NMOS transistor Q7, a third NMOS transistor Q8, a first inductor L1, a first capacitor C1, and a second capacitor C2.

[0066] This application's embodiments are combined with Figure 10 The working principle of the anti-current backflow circuit 500 is explained in detail below: The first controller 71 outputs the level signal DC_EN.

[0067] When the level signal DC_EN is low (i.e., the first type of level signal), both the second NPN transistor Q4 and the second PNP transistor Q5 are in the off state, and the enable signal EN is low (i.e., the first enable signal). The second controller 72 detects the first enable signal and controls the buck circuit 400 to enter the non-operating state. At the same time, the first NMOS transistor Q1, the first PNP transistor Q2, and the first NPN transistor Q3 are all in the off state. When the output port VOUT is connected to the load 101, the current loop for the load 101 to transmit the target current to the buck circuit 400 is broken by the first NMOS transistor Q1. Therefore, the target current transmitted by the load 101 to the buck circuit 400 cannot flow back into the buck circuit 400.

[0068] When the voltage level signal DC_EN is high (i.e., the second type of voltage level signal), both the second NPN transistor Q4 and the second PNP transistor Q5 are turned on, and the enable signal EN is high (i.e., the second enable signal). The second controller 72 detects the second enable signal and controls the buck circuit 400 to enter the working state. At the same time, the first NMOS transistor Q1, the first PNP transistor Q2, and the first NPN transistor Q3 are all turned on.

[0069] When a load 101 is connected to the output port VOUT, if the voltage of the load 101 is less than or equal to the voltage output by the buck circuit 400 in operation, the load 101 cannot reverse the target current to the buck circuit 400.

[0070] When the voltage of the load 101 is greater than the voltage output by the buck circuit 400 in operation, the first controller 71 detects that the target current is a negative current through the ISNS+ and ISNS- pins, sets the level signal DC_EN to a low level, that is, outputs a first-class level signal. At this time, the first NMOS transistor Q1, the first PNP transistor Q2, and the first NPN transistor Q3 switch from the on state to the off state, the current loop is broken, and the target current transmitted from the load 101 to the buck circuit 400 cannot flow back to the buck circuit 400.

[0071] In summary, the anti-current backflow circuit 500 provided in this application embodiment has at least the following technical effects: 1) The anti-current backflow circuit provided in this application embodiment can automatically switch between normal current output and current backflow conditions to ensure that the current cannot flow back into the step-down circuit, and at the same time ensure that the step-down circuit works normally.

[0072] 2) The anti-current backflow circuit provided in this application embodiment has a simple and scientific structure and low hardware cost.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A circuit for preventing reverse current flow, characterized in that, include: A current detection module is set in a preset current loop between the step-down circuit and the load, and is configured to detect the target current flowing through the current loop; The control module, connected to the current detection module, is configured to output a first-type level signal when the target current is a negative current, and to output a second-type level signal when the target current is a positive current. The buck enable module is electrically connected to the control module and the buck circuit respectively, and is configured to control the buck circuit to enter a non-operating state in response to the first type of level signal, or to control the buck circuit to enter an operating state in response to the second type of level signal. A switching module, disposed on the current loop between the step-down circuit and the load and electrically connected to the control module, is configured to, in response to a first type of level signal, disconnect the current loop to prevent the current from flowing back from the load to the step-down circuit, or, in response to a second type of level signal, connect the current loop so that the step-down circuit provides the target current to the load through the current loop.

2. The anti-current backflow circuit according to claim 1, characterized in that, The buck enable module includes: The enabling unit is electrically connected to the step-down circuit and is also subject to a preset battery voltage; The first trigger unit, electrically connected to the enabling unit and the control module respectively, is configured to, in response to the first type of level signal, control the enabling unit to output a first enabling signal to the buck circuit so that the buck circuit enters a non-operating state based on the first enabling signal; or, in response to the second type of level signal, control the enabling unit to output a second enabling signal to the buck circuit under the action of the battery voltage so that the buck circuit enters an operating state based on the second enabling signal.

3. The anti-current backflow circuit according to claim 2, characterized in that, The enabling unit includes: The first current-limiting voltage divider circuit is electrically connected to the step-down circuit. A first switching circuit, electrically connected to the first trigger unit and the first current-limiting voltage divider circuit respectively and also subjected to the battery voltage, is configured to, in response to a third-level signal output by the first trigger unit, output a first enable signal to the buck circuit through the first current-limiting voltage divider circuit, so that the buck circuit enters a non-operating state based on the first enable signal; or, in response to a fourth-level signal output by the first trigger unit, output a second enable signal to the buck circuit through the first current-limiting voltage divider circuit, so that the buck circuit enters a non-operating state based on the second enable signal.

4. The anti-current backflow circuit according to claim 2, characterized in that, The first triggering unit includes: The second current-limiting voltage divider circuit is electrically connected to the enabling unit. The second switching circuit, electrically connected to the second current-limiting voltage divider circuit and the control module, is configured to respond to a first type of level signal output by the control module, and control the enabling unit to output a first enabling signal to the buck circuit through the second current-limiting voltage divider circuit, so that the buck circuit enters a non-operating state based on the first enabling signal; or, in response to a second type of level signal output by the control module, control the enabling unit to output a second enabling signal to the buck circuit through the second current-limiting voltage divider circuit under the action of the battery voltage, so that the buck circuit enters an operating state based on the second enabling signal.

5. The anti-current backflow circuit according to claim 1, characterized in that, The switch switching module includes: A switching unit is disposed in the current loop between the step-down circuit and the load; The second trigger unit, electrically connected to the switching unit and the control module respectively, is configured to, in response to the first type of level signal, control the switching unit to disconnect the current loop to prevent the current from flowing back from the load to the buck circuit, or, in response to the second type of level signal, connect the current loop so that the buck circuit provides the target current to the load through the current loop.

6. The anti-current backflow circuit according to claim 5, characterized in that, The switching unit includes a first NMOS transistor, a first resistor, a second resistor, and a first PNP transistor. The first NMOS transistor is disposed in the current loop between the step-down circuit and the load, and the gate of the first NMOS transistor is electrically connected to the first end of the first resistor and the first end of the second resistor, respectively. The second end of the first resistor is grounded, and the second end of the second resistor is electrically connected to the collector of the first PNP transistor. A preset battery voltage is applied to the emitter of the first PNP transistor, and the base of the first PNP transistor is electrically connected to the second trigger unit. The first PNP transistor is configured to, in response to a fifth-level signal output by the second trigger unit, control the first NMOS transistor to disconnect the current loop to prevent the current from the load from flowing back into the buck circuit, or, in response to a sixth-level signal output by the second trigger unit, control the first NMOS transistor to connect the current loop so that the buck circuit provides the target current to the load through the current loop.

7. The anti-current backflow circuit according to claim 5, characterized in that, The second trigger unit includes a third resistor, a fourth resistor, and a first NPN transistor. The first end of the third resistor is electrically connected to the switching unit, the second end of the third resistor is electrically connected to the collector of the first NPN transistor, the emitter of the first NPN transistor is grounded, the base of the first NPN transistor is electrically connected to the first end of the fourth resistor, and the second end of the fourth resistor is electrically connected to the control module. The first NPN transistor is configured to, in response to a first type of level signal transmitted by the control module through the fourth resistor, control the switching unit to disconnect the current loop to prevent the current from flowing back into the buck circuit from the load, or, in response to a second type of level signal transmitted by the control module through the fourth resistor, connect the current loop so that the buck circuit provides the target current to the load through the current loop.

8. The anti-current reverse flow circuit according to any one of claims 1 to 7, characterized in that, The control module includes: The first controller is electrically connected to the buck enable module, the switch switching module and the current detection module respectively, and is configured to output a first type of level signal when the target current is a negative current, and output a second type of level signal when the target current is a positive current; The second controller is electrically connected to both the buck enable module and the buck circuit, and is configured to control the buck circuit to enter a non-operating state in response to a first enable signal output by the buck enable module, or to control the buck circuit to enter an operating state in response to a second enable signal output by the buck enable module.

9. A cigarette lighter, characterized in that, include: Step-down circuit; According to any one of claims 1 to 8, the anti-current backflow circuit, the switching module and the current detection module of the anti-current backflow circuit are both arranged in the current loop between the step-down circuit and the load.

10. An energy storage power source, characterized in that, Includes the cigarette lighter as described in any one of claims 1 to 9.

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