A power-on slope processing circuit and a fan

Abstract

The utility model discloses a power supply power on slope processing circuit and fan, and the circuit includes voltage dividing circuit, MOS switch circuit and RC charging circuit, voltage dividing circuit is connected with external input voltage, is used for voltage dividing processing to output control signal to input voltage, MOS switch circuit is connected with voltage dividing circuit and RC charging circuit respectively, and the control signal of voltage dividing circuit is used for controlling the conduction state of MOS switch circuit, RC charging circuit is connected with MOS switch circuit, is used for controlling the opening time and speed of switch element in MOS switch circuit to adjust the power on slope of output voltage. The utility model can effectively adjust the power on slope of output voltage, thereby solve the MCU work abnormity that the surge current impact, the oscillation of the prior art is caused to the problem, such as the power on slope of too slow MCU reset initialization failure, ensure that the fan and other load can be stably started and normally work under different power supply environment.

Description

Technical Field

[0001] This utility model relates to the field of electronic production technology, and in particular to a power supply slope processing circuit and a fan. Background Technology

[0002] Fans on the market are typically used in different environments, resulting in varying power-on slopes for normal fan operation. For example, using a P-MOS switching power supply can lead to an excessively fast power-on slope, causing surge currents or oscillations that can malfunction the MCU, resulting in abnormal fan startup. Conversely, an excessively slow power-on slope may prevent certain MCU reset circuits from triggering correctly, leading to MCU initialization failure and fan malfunction, causing the fan to freeze or fail to start. Therefore, to ensure proper fan startup without affecting normal operation, it is crucial to address the power supply voltage requirements for fan products. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a power supply slope processing circuit and a fan.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] On one hand, this utility model provides a power supply power-on slope processing circuit, including a voltage divider circuit, a MOS switching circuit, and an RC charging circuit; the voltage divider circuit is connected to an external input voltage and is used to divide the input voltage to output a control signal; the MOS switching circuit is connected to the voltage divider circuit and the RC charging circuit respectively, and the control signal output by the voltage divider circuit is used to control the conduction state of the MOS switching circuit; the RC charging circuit is connected to the MOS switching circuit and is used to control the turn-on time and speed of the switching element in the MOS switching circuit to adjust the power-on slope of the output voltage.

[0006] Furthermore, the voltage divider circuit includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 is connected to an external input voltage, and the other end of the first resistor R1 is connected to one end of the second resistor R2. The other end of the second resistor R2 is grounded, and the connection node between the first resistor R1 and the second resistor R2 outputs a control signal.

[0007] Furthermore, the MOS switching circuit includes a first MOS transistor Q1, a second MOS transistor Q2, and a third resistor R4; the gate of the second MOS transistor Q2 is connected to the output terminal of the voltage divider circuit, the source of the second MOS transistor Q2 is grounded, and the drain of the second MOS transistor Q2 is connected to the gate of the first MOS transistor Q1 through the third resistor R4; the source of the first MOS transistor Q1 is connected to the external input voltage, and the drain of the first MOS transistor Q1 serves as the output terminal of the output voltage.

[0008] Furthermore, the first MOS transistor Q1 is a PMOS transistor.

[0009] Furthermore, the second MOS transistor Q2 is an NMOS transistor.

[0010] Furthermore, the RC charging circuit includes a fourth resistor R3 and a first capacitor C2; one end of the fourth resistor R3 is connected to an external input voltage, and the other end of the fourth resistor R3 is connected to the gate of the first MOS transistor Q1 and one end of the first capacitor C2, respectively, and the other end of the first capacitor C2 is grounded.

[0011] Furthermore, the voltage divider circuit also includes a second capacitor C1. One end of the second capacitor C1 is connected to the connection node of the first resistor R1 and the second resistor R2, and the other end of the second capacitor C1 is grounded. The second capacitor C1 is used to filter the control signal output by the voltage divider circuit.

[0012] Furthermore, the resistance values ​​of the first resistor R1 and the second resistor R2 are different, and the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2.

[0013] On the other hand, the present invention also provides a fan including the power-on slope processing circuit described above.

[0014] The beneficial effects of this utility model compared with the prior art are as follows: A power supply power-on slope processing circuit includes a voltage divider circuit, a MOS switching circuit, and an RC charging circuit. The voltage divider circuit is connected to the external input voltage and is used to divide the input voltage to output a control signal. The MOS switching circuit is connected to both the voltage divider circuit and the RC charging circuit. The control signal output by the voltage divider circuit is used to control the conduction state of the MOS switching circuit. The RC charging circuit is connected to the MOS switching circuit and is used to control the turn-on time and speed of the switching elements in the MOS switching circuit to adjust the power-on slope of the output voltage. This utility model divides the external input voltage through the voltage divider circuit and outputs a control signal. This control signal is used to precisely control the conduction state of the MOS switching circuit. At the same time, combined with the RC charging circuit to regulate the turn-on time and speed of the switching elements in the MOS switching circuit, it can effectively adjust the power-on slope of the output voltage. This solves the problems in the prior art, such as surge current impact and oscillation caused by an excessively fast input voltage power-on slope, which leads to MCU malfunction, and the failure of MCU reset initialization caused by an excessively slow power-on slope. This ensures that loads such as fans can start stably and work normally under different power supply environments.

[0015] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model, it can be implemented according to the contents of the specification. In order to make the above and other objectives, features and advantages of this utility model more obvious and easy to understand, the following are preferred embodiments, which are described in detail below. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The circuit diagram shows a power-on slope processing circuit provided for a specific embodiment of this utility model. Detailed Implementation

[0018] The technical solution of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0019] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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 utility model.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0022] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0024] like Figure 1 As shown, this utility model embodiment provides a power supply power-on slope processing circuit, including a voltage divider circuit, a MOS switching circuit, and an RC charging circuit. The voltage divider circuit is connected to an external input voltage and is used to divide the input voltage to output a control signal. The MOS switching circuit is connected to both the voltage divider circuit and the RC charging circuit. The control signal output by the voltage divider circuit is used to control the conduction state of the MOS switching circuit. The RC charging circuit is connected to the MOS switching circuit and is used to control the turn-on time and speed of the switching elements in the MOS switching circuit to adjust the power-on slope of the output voltage.

[0025] This invention uses a voltage divider circuit to divide the external input voltage and output a control signal. This control signal is used to precisely control the conduction state of the MOS switching circuit. At the same time, combined with an RC charging circuit, the turn-on time and speed of the switching elements in the MOS switching circuit are regulated. This can effectively adjust the power-on slope of the output voltage, thereby solving the problems in the prior art such as surge current impact and oscillation caused by an excessively fast input voltage power-on slope, which leads to abnormal MCU operation, and the problem of MCU reset and initialization failure caused by an excessively slow power-on slope. This ensures that loads such as fans can start stably and work normally under different power supply environments.

[0026] In one embodiment, the voltage divider circuit includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 is connected to an external input voltage, and the other end of the first resistor R1 is connected to one end of the second resistor R2. The other end of the second resistor R2 is grounded, and the connection node between the first resistor R1 and the second resistor R2 outputs a control signal.

[0027] Specifically, the voltage divider circuit, serving as the voltage detection and control signal output module of the power supply slope processing circuit, mainly consists of a first resistor R1 and a second resistor R2. One end of the first resistor R1 is directly connected to the external input voltage VIN to receive the voltage signal from the external power supply system. The other end of the first resistor R1 is electrically connected to one end of the second resistor R2 via a wire, forming a series connection. The other end of the second resistor R2 is directly grounded (GND), forming a complete voltage divider loop. The connection point between the first resistor R1 and the second resistor R2 serves as the output terminal of the voltage divider circuit, used to output a control signal to the gate of the second MOSFET Q2 in the MOSFET switching circuit, thereby controlling the conduction of subsequent circuits.

[0028] The first resistor R1 and the second resistor R2 have different resistance values, with the first resistor R1 having a greater resistance than the second resistor R2. In this embodiment, the first resistor R1 is selected as 51KΩ, and the second resistor R2 is selected as 14KΩ. When the external input voltage VIN rises from 0, the current flows sequentially through the first resistor R1 and the second resistor R2. According to the series voltage divider principle, the voltage at the connection point of the first resistor R1 and the second resistor R2 (i.e., the output control signal voltage) is the product of the input voltage VIN and the resistance of the second resistor R2 divided by the sum of the resistances of the first resistor R1 and the second resistor R2. The calculation formula is: Control signal voltage = VIN × R2 / (R1 + R2). For example, when the external input voltage VIN rises to 12V, substituting the above parameters, we get the control signal voltage = 12V × 14KΩ / (51KΩ + 14KΩ) = 12V × 14 / 65 ≈ 2.58V. This voltage signal can drive the second MOSFET Q2 into the conduction state.

[0029] By using the series voltage divider structure of the first resistor R1 and the second resistor R2, the external input voltage VIN can be converted into a control signal voltage in a fixed ratio, ensuring the stability and accuracy of the control signal and providing a reliable triggering basis for the conduction state of the MOS switching circuit.

[0030] By selecting different values ​​for the first resistor R1 and the second resistor R2, the output threshold of the control signal can be flexibly adjusted. For example, when the power-on slope of the customer system input voltage is fast, a reasonable resistor value ratio can ensure that the control signal voltage rises at the expected speed, avoiding circuit oscillation caused by excessively fast triggering; when the power-on slope is slow, it can also ensure that the control signal voltage reaches the MOSFET turn-on threshold, guaranteeing the normal startup of subsequent circuits.

[0031] In one embodiment, the voltage divider circuit further includes a second capacitor C1. One end of the second capacitor C1 is connected to the connection node of the first resistor R1 and the second resistor R2, and the other end of the second capacitor C1 is grounded. The second capacitor C1 is used to filter the control signal output by the voltage divider circuit.

[0032] Specifically, one end of the second capacitor C1 is electrically connected to the connection point of the first resistor R1 and the second resistor R2 (i.e., the control signal output terminal of the voltage divider circuit) via a wire, and the other end is directly grounded (GND), forming an RC filter structure in parallel with the output terminal of the voltage divider circuit. Through this connection method, the second capacitor C1 can filter the control signal voltage output by the voltage divider circuit, eliminating high-frequency interference or fluctuations in the signal.

[0033] In one specific embodiment, the capacitance of the second capacitor C1 is selected as 1uF, which together with the first resistor R1 (51KΩ) and the second resistor R2 (14KΩ) constitutes a voltage divider filter circuit.

[0034] When high-frequency noise or voltage fluctuations exist during the power-on process of the external input voltage VIN, the control signal output by the voltage divider circuit (i.e., the voltage at the connection node of R1 and R2) may be accompanied by glitches or irregular fluctuations. Because the second capacitor C1 has the characteristic of "blocking DC and passing AC," the RC filter network formed by it, R1, and R2 can attenuate high-frequency interference signals: the high-frequency interference components will quickly ground through C1, while the main low-frequency control signal can be output stably.

[0035] In one embodiment, the MOS switching circuit includes a first MOS transistor Q1, a second MOS transistor Q2, and a third resistor R4; the gate of the second MOS transistor Q2 is connected to the output terminal of the voltage divider circuit, the source of the second MOS transistor Q2 is grounded, and the drain of the second MOS transistor Q2 is connected to the gate of the first MOS transistor Q1 through the third resistor R4; the source of the first MOS transistor Q1 is connected to the external input voltage, and the drain of the first MOS transistor Q1 serves as the output terminal of the output voltage.

[0036] Specifically, the first MOSFET Q1 is a PMOS transistor (model AO3401 can be selected), the second MOSFET Q2 is an NMOS transistor (model AO3400 can be selected), and the resistance value of the third resistor R4 is selected as 1KΩ.

[0037] When the external input voltage VIN starts to rise, the control signal voltage output by the voltage divider circuit gradually increases with VIN. When the control signal voltage reaches the turn-on threshold of the second MOSFET Q2 (NMOS), Q2 switches from the off state to the on state. At this time, a path is formed between the drain and source (ground) of Q2, and the gate of the first MOSFET Q1 is connected to ground through the third resistor R4, pulling the gate voltage low. Since Q1 is a PMOS transistor, its turn-on condition is that the gate voltage is lower than the source voltage (the source is connected to VIN). Therefore, when the gate voltage of Q1 drops below the turn-on threshold, Q1 switches from the off state to the on state, and the external input voltage VIN is output to the VOUT terminal through the source and drain of Q1 to supply power to the load.

[0038] By receiving the control signal from the voltage divider circuit through the second MOSFET Q2, the conduction and cutoff of Q2 can be precisely controlled according to the rise of the input voltage VIN. Then, the gate voltage of the first MOSFET Q1 is adjusted through the third resistor R4 to ensure that Q1 only turns on the output after the input voltage reaches a stable threshold, thus avoiding the surge current impact caused by the input voltage power-up slope being too fast.

[0039] In one embodiment, the RC charging circuit includes a fourth resistor R3 and a first capacitor C2; one end of the fourth resistor R3 is connected to an external input voltage, and the other end of the fourth resistor R3 is connected to the gate of the first MOSFET Q1 and one end of the first capacitor C2, respectively, and the other end of the first capacitor C2 is grounded.

[0040] One end of the fourth resistor R3 is directly connected to the external input voltage VIN to receive the external power supply voltage; the other end of the fourth resistor R3 is connected via wires to the gate of the first MOSFET Q1 and one end of the first capacitor C2, forming a circuit node; the other end of the first capacitor C2 is directly grounded (GND), forming a complete RC charging and discharging circuit. Through the above connections, the RC charging circuit is associated with the first MOSFET Q1 in the MOSFET switching circuit, realizing the control of the gate voltage change rate of Q1.

[0041] In this embodiment, the resistance of the fourth resistor R3 is selected as 20KΩ, and the capacitance of the first capacitor C2 is selected as 4.7uF.

[0042] When the external input voltage VIN is powered on, VIN charges the first capacitor C2 through the fourth resistor R3. At this time, the gate voltage of the first MOSFET Q1 gradually increases as C2 charges. Before the second MOSFET Q2 is turned on, C2 is in a charging state, and the gate voltage of Q1 is close to VIN. Since Q1 is a PMOS transistor (the turn-on condition is that the gate voltage is lower than the source voltage), Q1 is in the off state at this time, and there is no output voltage VOUT. When the control signal output by the voltage divider circuit turns on Q2, the gate of Q1 is grounded through the third resistor R4, C2 discharges through R4, the gate voltage gradually decreases, Q1 gradually turns on, and the output voltage VOUT slowly increases with the degree of conduction of Q1.

[0043] Based on the charging and discharging characteristics of the RC circuit, the time constant determines the charging and discharging speed of C2, which in turn controls the rate of change of the gate voltage of Q1.

[0044] The RC charging circuit composed of the fourth resistor R3 and the first capacitor C2 utilizes the time characteristics of RC charging and discharging to control the rate of change of the gate voltage of the first MOSFET Q1, so that the output voltage VOUT rises slowly at a preset slope. This effectively avoids surge current impact or oscillation caused by the input voltage power-up slope being too fast, protecting the fan, MCU and other loads from damage.

[0045] Overall, such as Figure 1 As shown, the main functions of R1, R2, C1, and Q2 are as follows: During the rise of the supply voltage VIN, the voltage divider R1 / R2 controls the Q2 switch. After Q2 turns on, R3 / R4 forms a circuit, thereby turning on the VOUT output voltage. By adjusting the resistance values ​​of R1 / R2, the VIN-VOUT turn-on voltage point (POR voltage) can be adjusted, thereby changing the voltage ramp rate supplied to the MCU. This prevents the MCU from failing to reset and initialize due to an excessively slow ramp rate, which would prevent the fan from working properly.

[0046] The main function of resistors R3, C2, R4, and Q1 is to prevent the fan from oscillating too quickly when the power supply voltage VIN is applied, or to prevent the IC from resetting abnormally due to an excessively short reset time. The gate of Q1 is connected to resistor R3 and capacitor C2 to form an RC charging circuit. Adjusting the RC parameters controls the turn-on time and speed of Q1, thereby improving the stability of the output voltage VOUT rise.

[0047] This invention also provides a fan, including the power-on slope processing circuit described above.

[0048] It should be noted that the fan provided in this embodiment of the invention includes the power-on slope processing circuit described above, and therefore the fan has all the beneficial effects of the power-on slope processing circuit described above, which will not be repeated here.

[0049] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A power supply slope processing circuit, characterized in that, It includes a voltage divider circuit, a MOS switching circuit, and an RC charging circuit. The voltage divider circuit is connected to an external input voltage and is used to divide the input voltage to output a control signal. The MOS switching circuit is connected to both the voltage divider circuit and the RC charging circuit. The control signal output by the voltage divider circuit is used to control the conduction state of the MOS switching circuit. The RC charging circuit is connected to the MOS switching circuit and is used to control the turn-on time and speed of the switching elements in the MOS switching circuit to adjust the power-on slope of the output voltage.

2. The power-on slope processing circuit according to claim 1, characterized in that, The voltage divider circuit includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 is connected to the external input voltage, and the other end of the first resistor R1 is connected to one end of the second resistor R2. The other end of the second resistor R2 is grounded, and the connection node between the first resistor R1 and the second resistor R2 outputs a control signal.

3. The power-on slope processing circuit according to claim 1, characterized in that, The MOS switching circuit includes a first MOS transistor Q1, a second MOS transistor Q2, and a third resistor R4; the gate of the second MOS transistor Q2 is connected to the output terminal of the voltage divider circuit, the source of the second MOS transistor Q2 is grounded, and the drain of the second MOS transistor Q2 is connected to the gate of the first MOS transistor Q1 through the third resistor R4; the source of the first MOS transistor Q1 is connected to the external input voltage, and the drain of the first MOS transistor Q1 serves as the output terminal of the output voltage.

4. The power-on slope processing circuit according to claim 3, characterized in that, The first MOS transistor Q1 is a PMOS transistor.

5. A power supply slope processing circuit according to claim 3 or 4, characterized in that, The second MOS transistor Q2 is an NMOS transistor.

6. The power supply slope processing circuit according to claim 1, characterized in that, The RC charging circuit includes a fourth resistor R3 and a first capacitor C2; one end of the fourth resistor R3 is connected to an external input voltage, and the other end of the fourth resistor R3 is connected to the gate of the first MOS transistor Q1 and one end of the first capacitor C2, respectively, and the other end of the first capacitor C2 is grounded.

7. The power-on slope processing circuit according to claim 1, characterized in that, The voltage divider circuit also includes a second capacitor C1. One end of the second capacitor C1 is connected to the connection node of the first resistor R1 and the second resistor R2, and the other end of the second capacitor C1 is grounded. The second capacitor C1 is used to filter the control signal output by the voltage divider circuit.

8. The power-on slope processing circuit according to claim 1, characterized in that, The first resistor R1 and the second resistor R2 have different resistance values, and the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2.

9. A fan, characterized in that, Includes the power-on slope processing circuit as described in any one of claims 1-8.

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