Voltage reduction circuit and electronic device

Abstract

The application discloses a reverse voltage boosting prevention step-down circuit and electronic equipment, and relates to the technical field of power management, which comprises a power input end, a power output end, a step-down conversion unit and a total control unit. The step-down conversion unit comprises a high-side switch tube, a low-side switch tube and a first inductor, the high-side switch tube and the low-side switch tube are connected in series between the power input end and a ground end in sequence, the connection point of the two is a switching node, and the first inductor is connected in series between the switching node and the power output end. The total control unit is provided with a first control end, a second control end, a first sampling end and a second sampling end, which are connected to the control end of the high-side switch tube and the low-side switch tube, the power input end and the switching node respectively, and the two switch tubes are controlled to be alternately turned on or turned off according to the voltage signal at the two ends of the high-side switch tube. By monitoring the voltage on both sides of the high-side switch tube in real time, the application can identify the reverse voltage boosting risk caused by current backflow in time and turn off the switch tube, thereby effectively protecting the input circuit from damage.

Description

Technical Field

[0001] This application relates to the field of power management technology, and in particular to a buck circuit and electronic device for preventing reverse boost. Background Technology

[0002] A BUCK circuit is a commonly used switching DC-DC step-down converter. Due to its advantages such as high efficiency, small size, and low cost, BUCK circuits are widely used in the power management systems of various electronic devices. However, in practical applications, the output of a BUCK circuit often needs to be connected to various external devices or loads. Taking a USB interface as an example, when a USB device is connected to the output of a BUCK circuit, some USB devices may have their own power supply or charging functions. This can cause current to flow backward from the USB device into the output of the BUCK circuit, forming the so-called "current reverse flow" phenomenon.

[0003] When reverse current occurs, the operating state of the BUCK circuit changes abnormally. Specifically, the reverse current forms a boost loop through the inductor and low-side switch at the output terminal. In this case, the inductor and the body diode of the low-side switch constitute a boost circuit, causing the voltage at the switching node to continuously rise, even exceeding the input voltage. Once the switching node voltage exceeds the input voltage, it will reverse charge the input terminal through the body diode of the high-side switch, causing an abnormally high input voltage. This could potentially damage the input circuit or other circuit modules connected to the input terminal, and in severe cases, even lead to a safety accident. Therefore, a simple and reliable circuit solution is urgently needed to effectively prevent the reverse boost phenomenon in the BUCK circuit when reverse current occurs, protecting the safety of the input circuit. Utility Model Content

[0004] This application aims to at least solve one of the technical problems existing in the prior art. To this end, this application proposes a buck circuit and electronic device to prevent reverse boost, which can effectively prevent the buck circuit from generating reverse boost when current flows back.

[0005] In a first aspect, embodiments of this application provide a buck circuit to prevent reverse boosting.

[0006] A buck converter circuit for preventing reverse boosting according to an embodiment of this application includes: a power input terminal; a power output terminal; a buck conversion unit including a high-side switch, a low-side switch, and a first inductor, wherein the high-side switch and the low-side switch are connected in series between the power input terminal and a ground terminal, the connection point of the high-side switch and the low-side switch is a switching node, and the first inductor is connected in series between the switching node and the power output terminal; and a main control unit, wherein a first control terminal and a second control terminal of the main control unit are respectively connected to the control terminal of the high-side switch and the control terminal of the low-side switch, and a first sampling terminal and a second sampling terminal of the main control unit are respectively connected to the power input terminal and the switching node, for controlling the high-side switch and the low-side switch to conduct alternately or controlling the high-side switch and the low-side switch to turn off according to the sampling voltage of the first sampling terminal and the second sampling terminal.

[0007] The buck circuit for preventing reverse boost according to the embodiments of this application has at least the following beneficial effects: By setting a first sampling terminal and a second sampling terminal on the main control unit, which are respectively connected to the power input terminal and the switching node, the main control unit can acquire the input voltage of the power input terminal and the node voltage of the switching node in real time. Based on the voltage signals acquired by these two sampling terminals, the main control unit determines whether the buck circuit is operating normally, and accordingly controls the high-side switching transistor and the low-side switching transistor to alternately conduct to achieve normal buck function, or controls the high-side switching transistor and the low-side switching transistor to turn off to stop the circuit operation when an abnormal situation is detected. This design can effectively identify the risk of reverse boost caused by current backflow. When the switching node voltage rises abnormally and exceeds the input voltage, the main control unit can turn off the switching transistor in time, cutting off the reverse boost circuit, thereby preventing high voltage from being transmitted in reverse to the power input terminal through the body diode of the high-side switching transistor, effectively protecting the input circuit and other circuit modules connected to the input terminal from damage. The embodiment of the buck circuit for preventing reverse boost has a simple structure and does not require additional complex protection circuits. Reliable reverse boost protection can be achieved simply by monitoring the voltage of key nodes and optimizing the control logic. It has the advantages of low cost, high reliability and easy implementation, and is suitable for various buck power supply applications that require prevention of current backflow.

[0008] According to some embodiments of this application, the central control unit includes: A drive control module is connected to the control terminals of the high-side switch and the low-side switch. The drive control module is used to generate drive signals to control the high-side switch and the low-side switch to alternately turn on and off. The drive control module also has an enable terminal. The reverse protection control module is provided with a power sampling input terminal, a node sampling input terminal, and a reverse protection control output terminal; the power sampling input terminal is connected to the power input terminal and is used to collect the input voltage of the power input terminal; the node sampling input terminal is connected to the switch node and is used to collect the node voltage of the switch node; the reverse protection control output terminal is connected to the enable terminal and is used to control the working state of the drive control module. Specifically, when the node voltage is greater than the input voltage, the anti-reverse control module controls the drive control module to stop working; when the node voltage is less than the input voltage, the anti-reverse control module controls the drive control module to work normally.

[0009] According to some embodiments of this application, the anti-reverse control module includes a voltage comparison component, the first input terminal of the voltage comparison component is connected to the power input terminal, and the second input terminal of the voltage comparison component is connected to the switching node.

[0010] According to some embodiments of this application, the anti-reverse control module further includes a power sampling component and a node sampling component; the power sampling component is connected in series between the power input terminal and the first input terminal, and the node sampling component is connected in series between the switch node and the second input terminal; the power sampling component and the node sampling component are used to proportionally reduce the received voltage.

[0011] According to some embodiments of this application, the power sampling component includes a third resistor and a fourth resistor, which are connected in series between the power input terminal and the ground terminal, and the connection point of the third resistor and the fourth resistor is connected to the first input terminal; the node sampling component includes a first resistor and a second resistor, which are connected in series between the switching node and the ground terminal, and the connection point of the first resistor and the second resistor is connected to the second input terminal.

[0012] According to some embodiments of this application, the resistance value of the first resistor is equal to the resistance value of the third resistor, and the resistance value of the second resistor is equal to the resistance value of the fourth resistor.

[0013] According to some embodiments of this application, the voltage comparison component is an operational amplifier.

[0014] According to some embodiments of this application, both the high-side switch and the low-side switch are MOSFETs.

[0015] According to some embodiments of this application, a filtering module is also included, the filtering module including an input filtering capacitor and an output filtering capacitor, the input filtering capacitor being connected in parallel between the power input terminal and the ground terminal, and the output filtering capacitor being connected in parallel between the power output terminal and the ground terminal.

[0016] Secondly, embodiments of this application also provide an electronic device. The electronic device includes a buck circuit to prevent reverse voltage boosting, as described in any of the embodiments of the first aspect. Attached Figure Description

[0017] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the circuit structure of a buck converter circuit to prevent reverse voltage boosting, as shown in the example. Detailed Implementation

[0018] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0019] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0020] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0021] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0022] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0023] In a first aspect, embodiments of this application provide a buck circuit to prevent reverse boosting.

[0024] The embodiment of the buck converter circuit for preventing reverse boost includes a power input terminal Vin, a power output terminal Vout, a buck converter unit, and a main control unit. The power input terminal receives external power and connects to a DC power source. The power output terminal supplies power to the load and connects to various electrical devices, such as powering external devices via a USB interface.

[0025] like Figure 1 As shown, the buck converter unit is the core component for voltage buck conversion, comprising a high-side switch Q1, a low-side switch Q2, and a first inductor L1. High-side switch Q1 and low-side switch Q2 are connected in series between the power input terminal Vin and the ground terminal GND. Specifically, one end of high-side switch Q1 is connected to the power input terminal Vin, and the other end is connected to one end of low-side switch Q2. The other end of low-side switch Q2 is connected to the ground terminal GND. The connection point between high-side switch Q1 and low-side switch Q2 is called the switching node Va. The first inductor L1 is connected in series between the switching node Va and the power output terminal Vout for energy storage and filtering, achieving smooth voltage output. Both high-side switch Q1 and low-side switch Q2 have control terminals, which receive control signals to control the on and off states of the switches. For example, high-side switch Q1 and low-side switch Q2 can be implemented using MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). MOSFET is a voltage-controlled switching device with advantages such as fast switching speed, low on-resistance, low drive power, and good thermal stability, making it very suitable for high-frequency switching power supply circuits.

[0026] It should be noted that in the above description, the ground terminal GND is the designated zero-potential reference point, and all voltage values ​​are relative to this ground terminal. In practice, the power input terminal includes two terminals: a positive input terminal and a negative input terminal, and the power output terminal also includes two terminals: a positive output terminal and a negative output terminal. In typical applications, the negative input terminal and the negative output terminal are connected together to form the common ground or zero-potential reference point of the circuit, the ground terminal GND. In this application, the power input terminal Vin specifically refers to the positive input terminal, and the power output terminal Vout specifically refers to the positive output terminal. For the sake of simplicity and ease of understanding, this application only marks the ground terminal GND as the zero-potential reference point of the circuit in the specification and related drawings, and does not describe the negative input terminal and the negative output terminal separately. However, those skilled in the art should understand that in actual circuits, the negative input terminal and the negative output terminal need to be connected to the ground terminal to form a complete current loop.

[0027] The central control unit (CCU) is responsible for the control and protection functions of the entire buck converter circuit. The CCU has a first control terminal and a second control terminal. The first control terminal is connected to the control terminal of the high-side switch Q1, and the second control terminal is connected to the control terminal of the low-side switch Q2, used to output drive signals to control the operating state of the two switches. The CCU also has a first sampling terminal and a second sampling terminal. The first sampling terminal is connected to the power input terminal Vin to acquire the input voltage signal; the second sampling terminal is connected to the switching node Va to acquire the voltage signal of the switching node. The CCU monitors the voltage state of the power input terminal and the switching node in real time through the first and second sampling terminals, and makes judgments and decisions based on the sampled voltage signals, thereby controlling the operating mode of the high-side switch Q1 and the low-side switch Q2.

[0028] Under normal operating conditions, when the input voltage at the power input terminal is higher than the node voltage of the switching node, it indicates that the buck circuit is in normal buck operation mode. At this time, the main control unit controls the high-side switch Q1 and the low-side switch Q2 to alternately turn on and off, achieving standard buck conversion. For example, when the high-side switch Q1 is on and the low-side switch Q2 is off, the input voltage charges the first inductor L1 through the high-side switch Q1, increasing the inductor current. When the high-side switch Q1 is off and the low-side switch Q2 is on, the first inductor L1 discharges through the low-side switch Q2, decreasing the inductor current. This alternating switching method achieves buck conversion from the input to the output.

[0029] However, when reverse current flows through the power output, such as when a USB device connected to the output supplies power to the buck circuit in reverse, the current will flow from the output through the first inductor L1 back into the switching node Va. If the low-side switch Q2 is turned on at this time, the reverse current will form a boost circuit through the body diode of the low-side switch Q2 and the first inductor L1, causing the voltage at the switching node Va to rise continuously. Once the voltage at the switching node exceeds the voltage at the power input, an abnormal situation occurs where the node voltage is greater than the input voltage. This means that the circuit has switched from buck mode to boost mode. At this time, the high voltage will be reversed through the body diode of the high-side switch Q1 to the power input, which may damage the input circuit. The embodiment of the buck circuit for preventing reverse boost addresses this problem by comparing and judging the sampled voltages at the first and second sampling terminals through the main control unit. When an abnormal increase in the voltage of the switching node is detected and exceeds the input voltage, the main control unit immediately controls the high-side switch Q1 and the low-side switch Q2 to turn off simultaneously, cutting off the boost circuit and preventing the voltage from continuing to rise. This effectively prevents reverse boost from damaging the power input terminal and the input circuit, achieving a reliable protection function.

[0030] Furthermore, such as Figure 1 As shown, in some embodiments, the main control unit includes two functional modules: a drive control module U1 and an anti-reverse control module. For example, the drive control module U1 can be implemented using a BUCK controller chip. This module has a high-side drive terminal HG and a low-side drive terminal LG, which are connected to the control terminals of the high-side switch Q1 and the low-side switch Q2, respectively. The drive control module U1 generates PWM drive signals and outputs complementary drive signals through the high-side drive terminal HG and the low-side drive terminal LG to control the high-side switch Q1 and the low-side switch Q2 to alternately turn on and off, thereby achieving normal buck conversion. The drive control module U1 also has an enable terminal EN, which controls the operating state of the drive control module. When the enable terminal receives a valid enable signal, the drive control module operates normally and outputs drive signals; when the enable terminal receives a disable signal, the drive control module stops working and no longer outputs drive signals. At this time, both the high-side switch Q1 and the low-side switch Q2 are in the off state.

[0031] The reverse voltage protection module monitors the circuit's operating status and, when necessary, shuts down the drive control module to prevent reverse voltage boosting. The module has three interfaces: a power sampling input, a node sampling input, and a reverse voltage protection output. The power sampling input is connected to the power input (Vin) to acquire the input voltage signal. The node sampling input is connected to the switching node (Va) to acquire the node voltage signal. The reverse voltage protection output is connected to the enable terminal (EN) of the drive control module U1 to output a control signal to control the drive control module's operating status. The reverse voltage protection module works by comparing the input voltage and the node voltage to determine if the circuit is in normal buck mode. When the node voltage (Va) is less than the input voltage (Vin), the circuit is in normal buck mode. At this time, the reverse voltage protection module outputs a valid enable signal to the enable terminal (EN) through the reverse voltage protection output, enabling the drive control module U1 to operate normally and continue outputting drive signals to control the switching transistors to conduct alternately. When the node voltage Va is greater than the input voltage Vin, it indicates that the circuit has an abnormal boost phenomenon. This is usually caused by current backflow at the output terminal. At this time, the anti-reverse control module immediately outputs a disable signal to the enable terminal EN through the anti-reverse control output terminal, so that the drive control module U1 stops working, thereby turning off the high-side switch Q1 and the low-side switch Q2, cutting off the boost circuit, and preventing the node voltage from continuing to rise and being transmitted in reverse to the input terminal.

[0032] Understandably, in some embodiments, the anti-reverse control module includes a voltage comparison component for comparing the input voltage with the node voltage. The voltage comparison component has a first input terminal and a second input terminal. The first input terminal is connected to the power input terminal Vin and is used to receive the input voltage signal or its voltage divider signal. The second input terminal is connected to the switching node Va and is used to receive the node voltage signal or its voltage divider signal. The voltage comparison component compares the voltage levels at the first and second input terminals and outputs a corresponding comparison result signal. This comparison result signal serves as the output signal of the anti-reverse control output terminal and is connected to the enable terminal of the drive control module, thereby controlling the start and stop of the drive control module.

[0033] Understandably, the voltage comparator can be implemented in various circuit configurations. In some embodiments, such as... Figure 1As shown, the voltage comparator component uses an operational amplifier U2A to construct a voltage comparator circuit. An operational amplifier is a high-gain differential amplifier that can be used as a voltage comparator when operating in open-loop or positive feedback mode, offering advantages such as fast response, high accuracy, and low cost. For example, the non-inverting input of operational amplifier U2A serves as the first input, the inverting input as the second input, and the output OUT is connected to the enable terminal EN of the drive control module as an anti-reverse control output. When the voltage at the first input is higher than the voltage at the second input, the operational amplifier outputs a high level, enabling the drive control module to operate normally; when the voltage at the second input is higher than the voltage at the first input, the operational amplifier outputs a low level, stopping the drive control module from operating. Of course, besides using an operational amplifier, the voltage comparator component can also be implemented using dedicated voltage comparator chips, such as the LM339 and LM393, common voltage comparator integrated circuits. These chips are specifically designed for voltage comparison applications, offering faster response speeds and lower power consumption. In addition, voltage comparator components can also employ comparator circuits composed of discrete components, such as differential comparator circuits using transistors or MOSFETs, controlling the output level state by the voltage difference between the two input terminals. In some applications, voltage comparator components can also be integrated into microcontrollers or digital signal processors, acquiring the voltage values ​​of the two input terminals through an analog-to-digital converter, performing digital comparison operations, and outputting a control signal. Those skilled in the art can select appropriate voltage comparator implementation methods based on specific application requirements, cost budgets, and performance requirements, as long as the function of comparing input voltages and node voltages and outputting corresponding control signals is achieved.

[0034] Understandably, in practical applications, the input voltage at the power input terminal Vin and the node voltage at the switching node Va may be relatively high, for example, the input voltage may reach 12V, 24V, or even higher. The operational amplifiers or comparator chips typically used in voltage comparator components often have limited operating voltage ranges. Directly connecting a high-voltage signal to the input terminal of the voltage comparator component may exceed its allowable input voltage range, leading to device damage or malfunction. Meanwhile, to improve the flexibility and adaptability of the circuit, enabling the reverse polarity control module to be applicable to applications with different voltage levels, in some embodiments, the reverse polarity control module further includes a power sampling component and a node sampling component.

[0035] A power sampling component is connected in series between the power input terminal Vin and the first input terminal of the voltage comparator component. It samples and processes the input voltage at the power input terminal, converting it into a voltage signal suitable for the voltage comparator component's operation. A node sampling component is connected in series between the switching node Va and the second input terminal of the voltage comparator component. It samples and processes the node voltage at the switching node, similarly converting it into a voltage signal suitable for the voltage comparator component's operation. A key function of these two sampling components is to proportionally reduce the received voltage. That is, the power sampling component and the node sampling component have the same voltage division ratio, ensuring that the voltage ratio between the input voltage and the node voltage remains unchanged after passing through their respective sampling components. This allows the voltage comparator component to accurately determine the magnitude relationship of the original voltages.

[0036] Power sampling components and node sampling components can be implemented using various circuit configurations. A common implementation is using a resistor divider network, which proportionally divides a high voltage into a low voltage through series resistors. Resistor divider networks offer advantages such as simple structure, low cost, and high reliability, and are widely used in various voltage sampling circuits. Besides resistor divider networks, sampling components can also be implemented using capacitor divider networks, utilizing the voltage-dividing characteristics of series capacitors to sample AC or pulsating voltages. This method is suitable for applications requiring DC isolation. In some high-precision applications, sampling components can also employ dedicated voltage attenuators or voltage follower circuits, using attenuation circuits composed of operational amplifiers to achieve precise proportional scaling. Furthermore, sampling components can also use optocouplers or isolation amplifiers to achieve electrically isolated voltage sampling, providing better safety and anti-interference capabilities in applications requiring input / output isolation. For digital control systems, sampling components can also be combined with resistor networks and buffer circuits to provide suitable sampling signals for analog-to-digital converters. Those skilled in the art can select appropriate implementation methods for power sampling components and node sampling components based on the actual voltage level, accuracy requirements, cost constraints, and environmental conditions.

[0037] In some embodiments, the power sampling component is implemented using a resistor divider network, for example, such as Figure 1As shown, the circuit includes a third resistor R3 and a fourth resistor R4. The third resistor R3 and the fourth resistor R4 are connected in series, and the entire series connection is between the power input terminal Vin and the ground terminal GND. One end of the third resistor R3 is connected to the power input terminal Vin, and the other end is connected to one end of the fourth resistor R4. The other end of the fourth resistor R4 is connected to the ground terminal GND. The connection point of the third resistor R3 and the fourth resistor R4 serves as the voltage divider output point, connected to the first input terminal of the voltage comparator component, such as the non-inverting input terminal of operational amplifier U2A. Through this voltage divider structure, the input voltage Vin is proportionally distributed across the third resistor R3 and the fourth resistor R4. The voltage at the connection point is equal to the input voltage multiplied by the ratio of the fourth resistor R4 to the total resistance of the two resistors, thus achieving a proportional voltage reduction. Similarly, the node sampling component also uses a resistor voltage divider network, including a first resistor R1 and a second resistor R2. The first resistor R1 and the second resistor R2 are connected in series. The entire series connection is between the switching node Va and the ground terminal GND. One end of the first resistor R1 is connected to the switching node Va, and the other end is connected to one end of the second resistor R2. The other end of the second resistor R2 is connected to the ground terminal GND. The connection point of the first resistor R1 and the second resistor R2 serves as the voltage divider output point, connected to the second input terminal of the voltage comparator component, such as the inverting input terminal of operational amplifier U2A. The switching node voltage Va is proportionally distributed across the first resistor R1 and the second resistor R2. The voltage at the connection point is equal to the node voltage multiplied by the ratio of the second resistor R2 to the total resistance of the two resistors.

[0038] Furthermore, to ensure the accuracy of voltage comparison and that the divided voltage still correctly reflects the magnitude of the original voltage, in some embodiments, the resistance values ​​of the first resistor R1 and the third resistor R3 are set to be equal, and the resistance values ​​of the second resistor R2 and the fourth resistor R4 are set to be equal. Through this symmetrical resistor configuration, the power supply sampling component and the node sampling component have exactly the same voltage division ratio; that is, the input voltage and the node voltage are scaled according to the same ratio. Thus, when the original node voltage Va equals the input voltage Vin, the voltages sent to the two input terminals of the voltage comparison component after voltage division are also equal; when the node voltage Va is greater than the input voltage Vin, the divided voltage sent to the second input terminal is correspondingly greater than the divided voltage sent to the first input terminal, and vice versa. At the same time, the same voltage division ratio simplifies circuit design and parameter calculation, facilitating engineering implementation. In practical applications, the specific resistance value can be determined by a combination of factors such as the range of input voltage, the input voltage requirements of the voltage comparison component, and power consumption limitations. For example, R1=R3=10kΩ and R2=R4=2kΩ can be selected to achieve a 5:1 voltage division ratio.

[0039] In some embodiments, a filtering module is further provided for filtering the input and output voltages to reduce voltage ripple and improve power quality. For example, such as... Figure 1 As shown, the filtering module includes an input filter capacitor EC1 and an output filter capacitor EC2. The input filter capacitor EC1 is connected in parallel between the power input terminal Vin and the ground terminal GND, close to the input side of the high-side switching transistor Q1. It is used to filter out high-frequency noise and ripple in the input power supply, providing a stable input voltage for the BUCK circuit, and simultaneously providing transient current support for the fast switching of the high-side switching transistor, reducing voltage spikes on the input power line. The output filter capacitor EC2 is connected in parallel between the power output terminal Vout and the ground terminal GND, forming an LC filter network together with the first inductor L1. It is used to smooth the output voltage, filter out the switching frequency and its harmonic components, and provide a stable DC output voltage to the load. The input and output filter capacitors can be electrolytic capacitors, ceramic capacitors, or a combination of both in parallel. The appropriate capacitor type and value are selected according to the voltage level, ripple requirements, and frequency characteristics. In practical applications, multiple capacitors of different values ​​and types can also be connected in parallel at the input and output terminals respectively to achieve better broadband filtering effects.

[0040] Secondly, embodiments of this application also provide an electronic device. The electronic device includes a buck circuit for preventing reverse voltage boosting, as described in any of the embodiments of the first aspect. The technical problems solved and the beneficial effects of the electronic device all originate from the buck circuit for preventing reverse voltage boosting, and will not be repeated here.

[0041] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A buck converter circuit for preventing reverse voltage boosting, characterized in that, include: Power input terminal; Power output terminal; A step-down converter unit includes a high-side switch, a low-side switch, and a first inductor. The high-side switch and the low-side switch are connected in series between the power input terminal and the ground terminal. The connection point between the high-side switch and the low-side switch is a switching node. The first inductor is connected in series between the switching node and the power output terminal. The main control unit has a first control terminal and a second control terminal connected to the control terminal of the high-side switch and the control terminal of the low-side switch, respectively. The first sampling terminal and the second sampling terminal of the main control unit are connected to the power input terminal and the switching node, respectively. The main control unit is used to control the high-side switch and the low-side switch to be turned on alternately or to control the high-side switch and the low-side switch to be turned off according to the sampling voltage of the first sampling terminal and the second sampling terminal.

2. The buck circuit for preventing reverse voltage boosting according to claim 1, characterized in that, The central control unit includes: A drive control module is connected to the control terminals of the high-side switch and the low-side switch. The drive control module is used to generate drive signals to control the high-side switch and the low-side switch to alternately turn on and off. The drive control module also has an enable terminal. The reverse protection control module is provided with a power sampling input terminal, a node sampling input terminal, and a reverse protection control output terminal; the power sampling input terminal is connected to the power input terminal and is used to collect the input voltage of the power input terminal; the node sampling input terminal is connected to the switch node and is used to collect the node voltage of the switch node; the reverse protection control output terminal is connected to the enable terminal and is used to control the working state of the drive control module. Specifically, when the node voltage is greater than the input voltage, the anti-reverse control module controls the drive control module to stop working; when the node voltage is less than the input voltage, the anti-reverse control module controls the drive control module to work normally.

3. The buck circuit for preventing reverse voltage boosting according to claim 2, characterized in that, The anti-reverse control module includes a voltage comparison component, the first input terminal of which is connected to the power input terminal, and the second input terminal of which is connected to the switching node.

4. The buck circuit for preventing reverse voltage boosting according to claim 3, characterized in that, The anti-reverse control module further includes a power sampling component and a node sampling component; the power sampling component is connected in series between the power input terminal and the first input terminal, and the node sampling component is connected in series between the switch node and the second input terminal; the power sampling component and the node sampling component are used to proportionally reduce the received voltage.

5. The buck circuit for preventing reverse boosting according to claim 4, characterized in that, The power sampling component includes a third resistor and a fourth resistor, which are connected in series between the power input terminal and the ground terminal. The connection point of the third resistor and the fourth resistor is connected to the first input terminal. The node sampling component includes a first resistor and a second resistor, which are connected in series between the switch node and the ground terminal. The connection point of the first resistor and the second resistor is connected to the second input terminal.

6. The buck converter circuit for preventing reverse boosting according to claim 5, characterized in that, The resistance of the first resistor is equal to the resistance of the third resistor, and the resistance of the second resistor is equal to the resistance of the fourth resistor.

7. The buck converter circuit for preventing reverse boosting according to claim 3, characterized in that, The voltage comparator is an operational amplifier.

8. The buck circuit for preventing reverse voltage boosting according to claim 1, characterized in that, Both the high-side switch and the low-side switch are MOSFETs.

9. The buck circuit for preventing reverse voltage boosting according to claim 1, characterized in that, It also includes a filtering module, which includes an input filtering capacitor and an output filtering capacitor. The input filtering capacitor is connected in parallel between the power input terminal and the ground terminal, and the output filtering capacitor is connected in parallel between the power output terminal and the ground terminal.

10. An electronic device, characterized in that, The electronic device is equipped with a buck circuit for preventing reverse voltage boost as described in any one of claims 1-9.

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