MOS tube driving circuit

Abstract

The utility model discloses an MOS tube drive circuit, comprising a power supply, a filter circuit and a drive circuit, the power supply is electrically connected with the filter circuit, the filter circuit is electrically connected with the drive circuit, the drive circuit comprises an isolation module, a starting module, a control module and a current limiting module, and the filter circuit is respectively electrically connected with the isolation module, the starting module, the control module and the current limiting module. The isolation module is electrically connected with the starting module and the current limiting module, the starting module is electrically connected with the control module and the current limiting module, and the control module is electrically connected with the current limiting module. The filter circuit is arranged to prevent noise of an input power supply from interfering with the MOS tube driving circuit, and meanwhile, the resistor is arranged at the grid electrode of the MOS tube to limit driving current and eliminate oscillation signals of the grid electrode, so that the MOS tube works more stably. Moreover, the driving circuit is provided with a triode as a starting module, and the current flowing through the control module is ensured to be maximum, so that the MOS tube is better driven.

Description

Technical Field

[0001] The utility model relates to the field of circuits, and in particular to a MOS tube driving circuit. Background Art

[0002] There are many types of MOS transistor drive circuits. Due to the relatively high operating frequency and input impedance of MOS transistors, and to prevent high-voltage circuits from damaging low-voltage control circuits, circuit isolation is often required to protect the MOS transistors. Magnetic isolation or optical isolation is commonly used. Magnetic isolation uses a transformer for isolation, while optical isolation uses an optocoupler. However, because magnetic isolation requires a complex and costly transformer design, optical isolation is the most common method of electrical isolation. However, the input power supply of the MOS transistor must be free of noise interference, otherwise it will damage the MOS transistor. Optocouplers, when used for circuit isolation, cannot isolate the input voltage from noise, causing the MOS transistor drive circuit to become unstable due to noise interference. Utility Model Content

[0003] In view of the shortcomings of the prior art, the present invention provides a MOS transistor driving circuit. The purpose of the present invention is achieved through the following solutions:

[0004] A MOS tube drive circuit comprises: a power supply, a filter circuit and a drive circuit, wherein the power supply is electrically connected to the filter circuit, the filter circuit is electrically connected to the drive circuit, the drive circuit comprises an isolation module (31), a start module, a control module and a current limiting module, the filter circuit is electrically connected to the isolation module, the start module, the control module and the current limiting module respectively, the isolation module is electrically connected to the start module and the current limiting module respectively, the start module is electrically connected to the control module and the current limiting module respectively, and the control module is electrically connected to the current limiting module.

[0005] In one embodiment, the filtering circuit includes a capacitor C1 and a capacitor C2, and the capacitor C1 and the capacitor C2 have a terminal 1 and a terminal 2 respectively. The terminal 1 and the terminal 2 of the capacitor C1 are respectively connected in parallel with the terminal 1 and the terminal 2 of the capacitor C2. The terminal 1 of the capacitor C1 and the capacitor C2 is electrically connected to the positive electrode of the power supply 1, and outputs the filtered voltage V+ to the drive circuit; the terminal 2 of the capacitor C1 and the capacitor C2 is electrically connected to the negative electrode of the power supply, and outputs the filtered voltage V- to the drive circuit; the terminal 1 of the capacitor C1 and the capacitor C2 is respectively electrically connected to the current limiting module, and the terminal 2 of the capacitor C1 and the capacitor C2 is electrically connected to the isolation module, the starting module and the control module.

[0006] In one embodiment, the isolation module includes an optocoupler U1, a resistor R1, and a resistor R2, the optocoupler U1 has terminals 1 to 6, the resistors R1 and R2 have terminals 1 and 2, respectively, terminal 1 of the optocoupler U1 is electrically connected to terminal 2 of the resistor R1, terminal 2 of the optocoupler U1 is grounded, terminal 3 of the optocoupler U1 is a normally closed contact, terminal 4 of the optocoupler U1 is electrically connected to the current limiting module, terminal 5 of the optocoupler U1 is electrically connected to the starting module and the current limiting module, respectively, terminal 6 of the optocoupler U1 is electrically connected to terminal 1 of the resistor R2, terminal 1 of the resistor R1 is externally connected to a signal input, and terminal 2 of the resistor R2 is electrically connected to the filtering circuit.

[0007] In one embodiment, the starting module includes a transistor Q1, which has a base B, a collector C and an emitter E, wherein the base B of the transistor Q1 is electrically connected to the isolation module and the current limiting module respectively, the collector C of the transistor Q1 is electrically connected to the current limiting module and the control module respectively, and the emitter E of the transistor Q1 is electrically connected to the control module and the filter circuit respectively.

[0008] In one embodiment, the control module includes a MOS transistor Q2 and a resistor R4. The MOS transistor Q2 has a gate G, a source S, and a drain D. The resistor R4 has a terminal 1 and a terminal 2. The source S of the MOS transistor Q2 is electrically connected to the filter circuit and the startup module, respectively. The gate G of the MOS transistor Q2 is electrically connected to the terminal 2 of the resistor R4. The drain D of the MOS transistor is connected to the output terminal. The terminal 1 of the resistor R4 is electrically connected to the startup module and the current limiting module, respectively.

[0009] In one embodiment, the current limiting module includes resistors R3, R5 and R6, and the resistors R3, R5 and R6 have terminal 1 and terminal 2 respectively. Terminal 1 of the resistor R3 is electrically connected to the filter circuit, and terminal 2 of the resistor R3 is electrically connected to the isolation module and the startup module respectively. Terminal 1 of R5 is electrically connected to terminal 2 of the resistor R6, the startup module and the control module respectively. Terminal 2 of the resistor R5 is electrically connected to the filter circuit, and terminal 1 of the resistor R6 is electrically connected to the isolation module.

[0010] In one embodiment, a display circuit is further included, which includes a display module and a protection resistor R. The display module and the protection resistor R respectively have terminal 1 and terminal 2. Terminal 1 of the display module is electrically connected to terminal 1 of the protection resistor R, terminal 2 of the display module is connected to the output terminal, and terminal 2 of the protection resistor R is electrically connected to the filter circuit.

[0011] In one embodiment, the power supply is a DC regulated power supply, and the voltage of the power supply is 24V.

[0012] Compared with the prior art, the present invention has at least the following advantages:

[0013] This utility model provides a MOS transistor drive circuit. By providing a filter circuit, it prevents noise from the input power supply from interfering with the MOS transistor drive circuit. A resistor is also provided at the gate of the MOS transistor to limit the drive current and eliminate gate oscillation signals, making the MOS transistor more stable. Furthermore, a transistor is provided in the drive circuit as a startup module to ensure maximum current flowing through the control module, thereby better driving the MOS transistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0015] Figure 1 This is a circuit diagram of a MOS tube driving circuit of the utility model;

[0016] Among them, the accompanying drawings are marked as follows: 1. power module; 2. filter circuit; 3. drive circuit; 31. isolation module; 32. start module; 33. control module; 34. current limiting module; 4. display circuit; 41. display module; 5. electrical equipment. DETAILED DESCRIPTION

[0017] The following diagrams illustrate various embodiments of the present invention. For clarity, many practical details will be included in the following description. However, it should be understood that these practical details are not intended to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not essential. Furthermore, to simplify the drawings, some commonly used structures and components are depicted in simplified schematic form.

[0018] It should be noted that all directional indications such as up, down, left, right, front, back, etc. in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0019] In addition, in the present invention, descriptions such as "first" and "second" are only used for descriptive purposes and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0020] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0021] like Figure 1 As shown, the utility model provides a MOS tube driving circuit, including: a power supply 1, a filter circuit 2 and a driving circuit 3. The power supply 1 is electrically connected to the filter circuit 2, and the filter circuit 2 is electrically connected to the driving circuit 3. The electric energy of the power supply 1 is filtered by the filter circuit 2 to reduce voltage noise interference, and then output to the driving circuit 3 by the filter circuit 2.

[0022] Furthermore, if Figure 1 As shown, the driving circuit 3 includes an isolation module 31, a starting module 32, a control module 33 and a current limiting module 34. The filtering circuit 2 is electrically connected to the isolation module 31, the driving module 32, the control module 33 and the current limiting module 34 respectively. The isolation module 31 is electrically connected to the starting module 32 and the current limiting module 34 respectively. The starting module 32 is electrically connected to the control module 33 and the current limiting module 34 respectively. The control module 33 is electrically connected to the current limiting module 34.

[0023] When the MOS tube drive circuit is operating, the isolation module 31 is externally connected to the MCU input signal. The start-up module 32 can turn on the control module 33 to enable it to perform control operations. The current limiting module 34 is used to provide current limiting protection for the MOS tube drive circuit. Specifically, during operation, the control module 33 is electrically connected to the electrical device 5. Thus, the isolation module 31 is used to isolate the drive module 32 and the control module 33 from the electrical device, preventing the high voltage and high current connected to the control module 33 from affecting the signal input of the MCU. At the same time, the power supply 1 is connected to the filter circuit to reduce the ripple of the input voltage and ensure the stability of the MOS tube drive circuit. The start-up module 32 is used to ensure that the current flowing through the control module is maximized, making it easier to start the control module 33.

[0024] Specifically, if Figure 1 As shown, filter circuit 2 includes capacitors C1 and C2. Capacitors C1 and C2 have terminals 1 and 2, respectively. Terminals 1 and 2 of capacitor C1 are connected in parallel with terminals 1 and 2 of capacitor C2, respectively. Terminals 1 of capacitors C1 and C2 are electrically connected to the positive electrode of power supply 1 and output a filtered voltage V+ to drive circuit 3. Terminals 2 of capacitors C1 and C2 are electrically connected to the negative electrode of power supply 1 and output a filtered voltage V- to the drive circuit. Terminals 1 of capacitors C1 and C2 are electrically connected to current limiting module 34, respectively. Terminals 2 of capacitors C1 and C2 are electrically connected to isolation module 31, startup module 32, and control module 33. When capacitors C1 and C2 are connected in parallel, the capacitances of C1 and C2 are added together. This reduces fluctuations in the voltage output of power supply 1 and the line voltage of the conductors, thereby improving the stability of the MOS transistor drive circuit.

[0025] Specifically, the isolation module 31 includes an optocoupler U1, a resistor R1 and a resistor R2, the optocoupler U1 has terminals 1 to 6, the resistors R1 and R2 have terminals 1 and 2 respectively, the terminal 1 of the optocoupler U1 is electrically connected to the terminal 2 of the resistor R1, the terminal 2 of the optocoupler U1 is grounded, the terminal 3 of the optocoupler U1 is a normally closed contact, the terminal 4 of the optocoupler U1 is electrically connected to the current limiting module (34), the terminal 5 of the optocoupler U1 is electrically connected to the starting module 32 and the current limiting module 34 respectively, the terminal 6 of the optocoupler U1 is electrically connected to the terminal 1 of the resistor R2, the terminal 1 of the resistor R1 is externally connected to the signal input, and the terminal 2 of the resistor R2 is electrically connected to the filter circuit 2.

[0026] Optocoupler U1's terminals 1, 2, and 3 are the primary side, while terminals 4, 5, and 6 are the secondary side. During operation of the MOS transistor drive circuit, the MCU's PTC MOS level signal is input to terminal 1 of resistor R1. Light-emitting diodes (LEDs) are internally located within terminals 1 and 2 of optocoupler U1, causing the LEDs to conduct and illuminate, thus energizing the primary side of optocoupler U1. Optocoupler U1's terminals 4, 5, and 6 contain phototransistors (BJTs). When illuminated by the LEDs, the BJTs conduct, also energizing the secondary side of optocoupler U1. When the BJTs conduct, terminal 3, being a normally closed contact, activates the internal relay of optocoupler U1 to disconnect the primary side. This isolates the MOS transistor drive circuit's signal input from other circuits and modules, preventing noise interference with the MOS transistor drive circuit's signal input circuit.

[0027] It should be noted that resistors R1 and R2 are current limiting protection resistors. Resistor R1 ensures that the output signal of the signal output end of the MCU is stable. Since terminal 6 of the optocoupler U1 is internally electrically connected to the base of the transistor BJT, leaving terminal 6 floating will cause unstable electrical level. Therefore, it is electrically connected to terminal 1 of resistor R2 to stabilize the electrical level.

[0028] Specifically, the starting module 32 includes a transistor Q1, which has a base B, a collector C and an emitter E, wherein the base B of the transistor Q1 is electrically connected to the isolation module 31 and the current limiting module 34 respectively, the collector C of the transistor Q1 is electrically connected to the current limiting module 34 and the control module 33 respectively, and the emitter E of the transistor Q1 is electrically connected to the filter circuit 2, wherein the transistor Q1 serves as an amplifying element of the circuit. When the output filtered voltage V+ of the filter circuit is input to the base B of the transistor from the current limiting module 34, and the collector C of the transistor is also input with the filtered voltage V+ via the current limiting module 34, the voltages of the base and collector C of the transistor Q1 are the same, and the current output by the transistor Q1 is the largest, thereby better starting the control module.

[0029] Specifically, the control module 33 includes a MOS transistor Q2 and a resistor R4. The MOS transistor Q2 has a gate G, a source S, and a drain D. The resistor R4 has a terminal 1 and a terminal 2. The source S of the MOS transistor Q2 is electrically connected to the filter circuit 2 and the startup module 32, respectively. The gate G of the MOS transistor Q2 is electrically connected to the terminal 2 of the resistor R4. The drain D of the MOS transistor is connected to the output terminal. The terminal 1 of the resistor R4 is electrically connected to the startup module 32 and the current limiting module 34, respectively. When the MOS transistor Q2 drive circuit is in operation, the MOS transistor Q2 can control the electrical device 5. The resistor R4 acts as a current-limiting resistor to prevent damage to the MOS transistor Q2 due to excessive current. Furthermore, it can limit the drive current, thereby eliminating the oscillation signal of the gate G, and ensuring more stable operation of the MOS transistor Q2.

[0030] Specifically, the current limiting module 34 includes resistors R3, R5, and R6. Resistors R3, R5, and R6 each have a terminal 1 and a terminal 2. Terminal 1 of resistor R3 is electrically connected to the filter circuit 2, and terminal 2 of resistor R3 is electrically connected to the isolation module 31 and the startup module 32, respectively. Terminal 1 of resistor R5 is electrically connected to terminal 2 of resistor R6, the startup module 32, and the control module 33, respectively. Terminal 2 of resistor R5 is electrically connected to the filter circuit 2, and terminal 1 of resistor R6 is electrically connected to the isolation module 31. Resistors R3, R5, and R6 limit the voltage and current input to the filter circuit 2 to protect the components of the MOS transistor drive circuit.

[0031] Furthermore, the MOS transistor driving circuit also includes a display circuit 4, which includes a display module 41 and a protection resistor R. The display module 41 and the protection resistor R respectively have a terminal 1 and a terminal 2. The terminal 1 of the display module 41 is electrically connected to the terminal 1 of the protection resistor R, the terminal 2 of the display module 41 is connected to the output terminal, and the terminal 2 of the protection resistor R is electrically connected to the filter circuit 2.

[0032] Among them, the display module 41 can display the voltage and current in the circuit. At the same time, in specific implementation, it can display the parameters of the electrical equipment connected to the control module. The protection resistor R is used to prevent the power input voltage and current from being too large to damage the display module. Among them, the display module is an LED screen.

[0033] Furthermore, the power supply 1 is a DC regulated power supply. It should be noted that the DC regulated power supply can output stable DC power with less residual noise signals, thereby ensuring the stability of the MOS tube drive circuit, wherein the voltage of the power supply 1 is 24V.

[0034] In summary, during implementation, the MCU inputs the PTC MOS signal to terminal 1 of optocoupler U1. This causes the light-emitting diode (LED) inside optocoupler U1 to turn on and illuminate the phototransistor (BJT) inside optocoupler U1, turning it on. Terminal 3 of optocoupler U1 is a normally closed contact, controlling an internal relay to disconnect the primary circuit of optocoupler U1. This prevents interference with the primary signal input circuit of optocoupler U1 and maintains signal input stability. Simultaneously, the voltage V+ output by the filter circuit is input to the base B and collector C of transistor U1 via terminal 1 of resistor R3 and terminal 2 of resistor R5. The voltages at the base B and collector C of transistor U1 are equal, maximizing the output current of transistor Q1. Since the source S of MOS transistor Q2 is electrically connected to the output voltage V- of the filter circuit, the output voltage V+- of the filter circuit is input to the gate G of MOS transistor Q2, making the voltage at gate G greater than the voltage at source S, thereby driving MOS transistor Q2 on. In this way, the drain D of the MOS transistor Q2 can output a voltage to control the electrical device 5 .

[0035] The above is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims of the present invention.

Claims

1. A MOS tube driving circuit, characterized in that: include: A power supply (1), a filter circuit (2) and a drive circuit (3), wherein the power supply (1) is electrically connected to the filter circuit (2), the filter circuit (2) is electrically connected to the drive circuit (3), and the drive circuit (3) comprises an isolation module (31), a start module (32), a control module (33) and a current limiting module (34); the filter circuit (2) is electrically connected to the isolation module (31), the start module (32), the control module (33) and the current limiting module (34), respectively; the isolation module (31) is electrically connected to the start module (32) and the current limiting module (34), respectively; the start module (32) is electrically connected to the control module (33) and the current limiting module (34), respectively; and the control module (33) is electrically connected to the current limiting module (34).

2. The MOS transistor driving circuit according to claim 1, characterized in that: The filter circuit (2) includes a capacitor C1 and a capacitor C2, the capacitor C1 and the capacitor C2 respectively having a terminal 1 and a terminal 2, the terminal 1 and the terminal 2 of the capacitor C1 are respectively connected in parallel with the terminal 1 and the terminal 2 of the capacitor C2, the terminal 1 of the capacitor C1 and the capacitor C2 are electrically connected to the positive electrode of the power supply (1), and output the filtered voltage V+ to the drive circuit (3); the terminal 2 of the capacitor C1 and the capacitor C2 are electrically connected to the negative electrode of the power supply (1), and output the filtered voltage V- to the drive circuit; the terminal 1 of the capacitor C1 and the capacitor C2 are respectively electrically connected to the current limiting module (34), and the terminal 2 of the capacitor C1 and the capacitor C2 are electrically connected to the isolation module (31), the starting module (32) and the control module (33).

3. The MOS transistor driving circuit according to claim 1, wherein: The isolation module (31) includes an optocoupler U1, a resistor R1, and a resistor R2. The optocoupler U1 has terminals 1 to 6. The resistors R1 and R2 respectively have terminals 1 and 2. Terminal 1 of the optocoupler U1 is electrically connected to terminal 2 of the resistor R1. Terminal 2 of the optocoupler U1 is grounded. Terminal 3 of the optocoupler U1 is a normally closed contact. Terminal 4 of the optocoupler U1 is electrically connected to the current limiting module (34). Terminal 5 of the optocoupler U1 is electrically connected to the starting module (32) and the current limiting module (34). Terminal 6 of the optocoupler U1 is electrically connected to terminal 1 of the resistor R2. Terminal 1 of the resistor R1 is externally connected to a signal input. Terminal 2 of the resistor R2 is electrically connected to the filter circuit (2).

4. The MOS transistor driving circuit according to claim 1, characterized in that: The startup module (32) includes a transistor Q1, and the transistor Q1 has a base B, a collector C, and an emitter E, wherein the base B of the transistor Q1 is electrically connected to the isolation module (31) and the current limiting module (34), respectively; the collector C of the transistor Q1 is electrically connected to the current limiting module (34) and the control module (33), respectively; and the emitter E of the transistor Q1 is electrically connected to the control module (33) and the filter circuit (2), respectively.

5. The MOS transistor driving circuit according to claim 1, characterized in that: The control module (33) includes a MOS tube Q2 and a resistor R4, wherein the MOS tube Q2 has a gate G, a source S, and a drain D, and the resistor R4 has a terminal 1 and a terminal 2. The source S of the MOS tube Q2 is electrically connected to the filter circuit (2) and the start-up module (32), respectively. The gate G of the MOS tube Q2 is electrically connected to the terminal 2 of the resistor R4, and the drain D of the MOS tube is connected to the output terminal. The terminal 1 of the resistor R4 is electrically connected to the start-up module (32) and the current limiting module (34), respectively.

6. The MOS transistor driving circuit according to claim 1, characterized in that: The current limiting module (34) includes resistors R3, R5, and R6. The resistors R3, R5, and R6 respectively have a terminal 1 and a terminal 2. Terminal 1 of the resistor R3 is electrically connected to the filter circuit (2). Terminal 2 of the resistor R3 is electrically connected to the isolation module (31) and the start-up module (32). Terminal 1 of R5 is electrically connected to terminal 2 of the resistor R6, the start-up module (32), and the control module (33). Terminal 2 of the resistor R5 is electrically connected to the filter circuit (2). Terminal 1 of the resistor R6 is electrically connected to the isolation module (31).

7. The MOS transistor driving circuit according to claim 1, characterized in that: The device further comprises a display circuit (4), wherein the display circuit (4) comprises a display module (41) and a protective resistor R, wherein the display module (41) and the protective resistor R respectively have a terminal 1 and a terminal 2, wherein the terminal 1 of the display module (41) is electrically connected to the terminal 1 of the protective resistor R, the terminal 2 of the display module (41) is connected to the output terminal, and the terminal 2 of the protective resistor R is electrically connected to the filter circuit (2).

8. The MOS transistor driving circuit according to claim 1, characterized in that: The power supply (1) is a DC regulated power supply, and the voltage of the power supply (1) is 24V.

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