MOS (Metal Oxide Semiconductor) tube travel control circuit with AC (Alternating Current) isolation function
By introducing a MOS transistor stroke control circuit with AC isolation function, the safety hazards of traditional film winding machines in AC leakage environment and the problem of arc pitting of mechanical contacts are solved, thereby achieving the reliability and life extension of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SICHUAN CHENHE ELECTRIC MASCH MFG CO LTD
- Filing Date
- 2025-06-05
- Publication Date
- 2026-05-15
AI Technical Summary
In existing technologies, traditional film winding machines pose significant safety hazards in working environments with AC leakage or large power fluctuations, and the mechanical contacts are prone to arc pitting, affecting the reliability and lifespan of the equipment.
A MOSFET travel control circuit with AC isolation function is adopted, including a power input unit, a MOSFET control unit, a travel switch unit, and an AC isolation unit. The MOSFET control unit replaces the mechanical contacts to eliminate the problem of arc pitting, and the AC isolation unit blocks AC interference to prevent malfunction.
It effectively prevents the film winding motor from malfunctioning under unexpected conditions, extends the service life of the equipment, improves the reliability and safety of the system, and avoids damage caused by malfunctions.
Smart Images
Figure CN224249579U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of redundant power supply and high-voltage wiring technology, specifically relating to a MOS transistor travel control circuit with AC isolation function. Background Technology
[0002] Traditional film rollers are crucial devices used in agricultural greenhouses and industrial shading applications to control the opening and closing of film rolls. Their performance and reliability directly affect the stable operation and safety of the entire system. However, currently widely used traditional film rollers typically employ a combination of diodes and limit switches to control the motor's forward and reverse rotation and travel limits. While this design is relatively simple in structure, it has revealed numerous problems in practical applications that urgently need to be addressed.
[0003] Specifically, traditional film winding machines pose significant safety hazards in operating environments with AC leakage or large power ripple. Because AC power is directly rectified through diodes, when there is leakage in the power grid or large power fluctuations, the rectified DC power may contain a significant AC component, causing the film winding motor to malfunction unexpectedly. This malfunction not only disrupts the normal opening and closing rhythm of the film winding machine but may also impact the limit switches, causing them to gradually fail and affecting the precise control of the entire film winding system. More seriously, limit switch failure can trigger a series of chain reactions, such as excessive stretching and tearing of the film, or even structural damage to the entire greenhouse or shading system, resulting in substantial economic losses and safety hazards for users.
[0004] Furthermore, the mechanical contacts used in traditional film winding machines face the serious challenge of arc pitting corrosion during long-term use. During switching processes, mechanical contacts generate electric arcs, which, over time, lead to pitting corrosion on the contact surface. This results in increased contact resistance, intensified heat generation, and ultimately affects the contact's lifespan and reliability. This problem is particularly prominent in high-frequency, high-load applications, severely limiting the performance and service life of the film winding machine.
[0005] Therefore, there is an urgent need for a MOS transistor stroke control circuit with AC isolation function that can prevent malfunction of the film winding motor and eliminate arc pitting. Utility Model Content
[0006] The purpose of this invention is to provide a MOS transistor travel control circuit with AC isolation function to solve the above-mentioned problems existing in the prior art.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] This utility model provides a MOSFET travel control circuit with AC isolation function, including: a power input unit, a MOSFET control unit, a travel switch unit and an AC isolation unit;
[0009] The power supply port of the power input unit is electrically connected to the power supply input terminal of the AC isolation unit. The isolation power supply output terminal of the AC isolation unit is electrically connected to the power supply input terminals of the MOS transistor control unit and the limit switch unit. The feedback output terminal of the limit switch unit is electrically connected to the feedback input terminal of the MOS transistor control unit. The control signal output terminal of the MOS transistor control unit is electrically connected to the controlled input terminal of the film winding motor. The output terminal of the AC isolation unit is electrically connected to the input terminal of the film winding motor.
[0010] In one possible design, the MOS transistor control unit includes a first MOS transistor, a second MOS transistor, a first current-limiting drive subunit, and a second current-limiting drive subunit;
[0011] Wherein, the source of the first MOS transistor is electrically connected to the first power supply port of the power input unit, the source of the second MOS transistor is electrically connected to the second power supply port of the power input unit, the gate of the first MOS transistor is electrically connected to the drive output terminal of the first current limiting drive subunit, the gate of the second MOS transistor is electrically connected to the drive output terminal of the second current limiting drive subunit, the drain of the first MOS transistor is electrically connected to the first controlled input terminal of the winding motor, and the drain of the second MOS transistor is electrically connected to the second controlled input terminal of the winding motor;
[0012] The input terminals of the first current-limiting drive subunit and the second current-limiting drive subunit serve as the feedback input terminals of the MOS transistor control unit and are electrically connected to the feedback output terminal of the limit switch unit.
[0013] In one possible design, the first current-limiting drive subunit includes a first transistor, a third resistor, a seventh resistor, an eighth resistor, and a fifth diode, and the second current-limiting drive subunit includes a second transistor, a fourth resistor, a fifth resistor, a ninth resistor, and a fourth diode.
[0014] Wherein, the collector of the first transistor serves as the drive output terminal of the first current limiting drive subunit, and is electrically connected to the gate of the first MOS transistor through the third resistor; the feedback output terminal of the limit switch unit is electrically connected to the base of the first transistor; the second power supply port of the power input unit is electrically connected to one end of the fifth diode; the other end of the fifth diode is electrically connected to the emitter of the first transistor; the seventh resistor is electrically connected between the gate and the source of the first MOS transistor; and the eighth resistor is electrically connected between the base and the emitter of the first transistor.
[0015] The collector of the second transistor serves as the drive output terminal of the second current-limiting drive subunit and is electrically connected to the gate of the second MOS transistor via the fourth resistor. The feedback output terminal of the limit switch unit is electrically connected to the base of the second transistor. The first power supply port of the power input unit is electrically connected to one end of the fourth diode, and the other end of the fourth diode is electrically connected to the emitter of the second transistor. The fifth resistor is electrically connected between the gate and source of the second MOS transistor, and the ninth resistor is electrically connected between the base and emitter of the second transistor.
[0016] In one possible design, the limit switch unit includes a left limit switch subunit and a right limit switch subunit;
[0017] Wherein, the power supply input terminal of the left travel switch subunit is electrically connected to the first power supply port of the power input unit, and the feedback output terminal of the left travel switch subunit is electrically connected to the base of the first transistor;
[0018] The power supply input terminal of the right-side limit switch subunit is electrically connected to the second power supply port of the power input unit, and the feedback output terminal of the right-side limit switch subunit is electrically connected to the base of the second transistor.
[0019] In one possible design, the left limit switch subunit includes a left limit switch, a first resistor, and a first diode, and the right limit switch subunit includes a right limit switch, a second resistor, and a second diode;
[0020] Wherein, the first power supply port of the power input unit is electrically connected to one end of the first diode, the other end of the first diode is electrically connected to the power supply input terminal of the left limit switch, and the feedback output terminal of the left limit switch is electrically connected to the base of the first transistor after passing through the first resistor;
[0021] The second power supply port of the power input unit is electrically connected to one end of the second diode, and the other end of the second diode is electrically connected to the power supply input terminal of the right limit switch. The feedback output terminal of the right limit switch is electrically connected to the base of the second transistor after passing through the second resistor.
[0022] In one possible design, the AC isolation unit includes a four-pin connector, a first capacitor, a first rectifier bridge, and a first relay;
[0023] Wherein, the power supply input terminal of the first relay is electrically connected to the power supply port of the power input unit, and the normally closed contact of the first relay serves as the isolation power supply output terminal of the AC isolation unit, and is electrically connected to the power supply input terminal of the MOS transistor control unit and the limit switch unit;
[0024] The coil of the first relay is electrically connected to the AC input terminal of the first rectifier bridge, the first DC output terminal of the first rectifier bridge is electrically connected to one end of the first capacitor, the other end of the first capacitor is electrically connected to the first pin of the four-pin connector, the second DC output terminal of the first rectifier bridge is electrically connected to the second pin of the four-pin connector, and the third and fourth pins of the four-pin connector serve as the output terminals of the AC isolation unit and are electrically connected to the input terminal of the film winding motor.
[0025] The first pin of the four-pin connector is also electrically connected to the first relay, and the second pin of the four-pin connector is also electrically connected to the power supply port of the power input unit.
[0026] In one possible design, the AC isolation unit also includes a sixth resistor and an AC alarm indicator light;
[0027] The power supply port of the power input unit and the common terminal of the second pin of the four-pin connector are connected to one end of the AC alarm indicator light through the sixth resistor, and the other end of the AC alarm indicator light is connected to the first relay.
[0028] In one possible design, the first relay is a relay of model HF41F / 12-ZS.
[0029] Beneficial Effects: This utility model provides a MOSFET travel control circuit with AC isolation function, including a power input unit, a MOSFET control unit, a travel switch unit, and an AC isolation unit. The power supply port of the power input unit is electrically connected to the power supply input terminal of the AC isolation unit. The isolation power supply output terminal of the AC isolation unit is electrically connected to the power supply input terminals of the MOSFET control unit and the travel switch unit. The feedback output terminal of the travel switch unit is electrically connected to the feedback input terminal of the MOSFET control unit. The control signal output terminal of the MOSFET control unit is electrically connected to the controlled input terminal of the film winding motor. The output terminal of the AC isolation unit is electrically connected to the input terminal of the film winding motor. By replacing traditional mechanical contacts with the MOSFET control unit, the problem of high-current arcing is eliminated, extending the service life of the control circuit provided by this utility model. Furthermore, by introducing the AC isolation unit, AC interference is effectively blocked, preventing malfunction of the travel switch unit that could cause the film winding motor to fail to stop. Attached Figure Description
[0030] Figure 1 A functional block diagram of a MOS transistor travel control circuit with AC isolation function provided in an embodiment of this utility model;
[0031] Figure 2 A circuit diagram of the MOS transistor control unit and the limit switch unit provided in the embodiments of this utility model;
[0032] Figure 3 A circuit diagram of an AC isolation unit provided in an embodiment of this utility model.
[0033] The components include: 1. Power input unit; 2. MOSFET control unit; 3. Limit switch unit; 4. AC isolation unit; and 5. Film winding motor.
[0034] R1: First resistor; R2: Second resistor; R3: Third resistor; R4: Fourth resistor; R5: Fifth resistor; R6: Sixth resistor; R7: Seventh resistor; R8: Eighth resistor; R9: Ninth resistor; D1: First diode; D2: Second diode; D3: First rectifier bridge; D4: Fourth diode; D5: Fifth diode; U1: First MOSFET; U2: Second MOSFET; Q1: First transistor; Q2: Second transistor; C1: First capacitor; K1: First relay; SW1: Left limit switch; SW2: Right limit switch; CN1: Four-pin connector; LED1: AC alarm indicator. Detailed Implementation
[0035] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the present utility model will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the description of these embodiments is used to help understand this utility model, but does not constitute a limitation on this utility model.
[0036] It should be understood that although the terms first, second, etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, the first unit may be referred to as the second unit, and similarly, the second unit may be referred to as the first unit, without departing from the scope of the exemplary embodiments of this utility model.
[0037] It should be understood that the term "and / or" that may appear in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" that may appear in this document describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this document generally indicates that the related objects before and after it are in an "or" relationship.
[0038] Example 1:
[0039] like Figure 1 As shown, this embodiment provides a MOS transistor travel control circuit with AC isolation function, including: a power input unit 1, a MOS transistor control unit 2, a travel switch unit 3, and an AC isolation unit 4;
[0040] The power supply port of the power input unit 1 is electrically connected to the power supply input terminal of the MOS transistor control unit 2, the feedback output terminal of the limit switch unit 3 is electrically connected to the feedback input terminal of the MOS transistor control unit 2, and the control signal output terminal of the MOS transistor control unit 2 is electrically connected to the controlled input terminal of the film winding motor 5.
[0041] The power supply port of the power input unit 1 is electrically connected to the power supply input terminal of the AC isolation unit 4, and the output terminal of the AC isolation unit 4 is electrically connected to the input terminal of the film winding motor 5.
[0042] It should be noted that the MOS transistor control unit 2 replaces the traditional mechanical contacts to eliminate the problem of high-current arcing and erosion, thus extending the working life of the control circuit provided in this embodiment. Furthermore, by introducing the AC isolation unit 4, AC interference is effectively blocked to prevent the limit switch unit 3 from malfunctioning and causing the film winding motor 5 to fail to stop in the event of AC leakage in the control cabinet or poor filtering of the control power supply with large ripple.
[0043] Example 2:
[0044] like Figure 2-3 As shown, this embodiment provides a MOS transistor travel control circuit with AC isolation function. In one possible implementation, the MOS transistor control unit 2 includes a first MOS transistor U1, a second MOS transistor U2, a first current limiting drive subunit, and a second current limiting drive subunit.
[0045] Wherein, the source of the first MOS transistor U1 is electrically connected to the first power supply port of the power input unit 1, the source of the second MOS transistor U2 is electrically connected to the second power supply port of the power input unit 1, the gate of the first MOS transistor U1 is electrically connected to the drive output terminal of the first current limiting drive subunit, the gate of the second MOS transistor U2 is electrically connected to the drive output terminal of the second current limiting drive subunit, the drain of the first MOS transistor U1 is electrically connected to the first controlled input terminal of the winding motor 5, and the drain of the second MOS transistor U2 is electrically connected to the second controlled input terminal of the winding motor 5;
[0046] The input terminals of the first current-limiting drive subunit and the second current-limiting drive subunit serve as the feedback input terminals of the MOS transistor control unit 2, and are electrically connected to the feedback output terminal of the limit switch unit 3.
[0047] In one possible implementation, the first current-limiting drive subunit includes a first transistor Q1, a third resistor R3, a seventh resistor R7, an eighth resistor R8 and a fifth diode D5, and the second current-limiting drive subunit includes a second transistor Q2, a fourth resistor R4, a fifth resistor R5, a ninth resistor R9 and a fourth diode D4.
[0048] Wherein, the collector of the first transistor Q1 serves as the drive output terminal of the first current limiting drive subunit, and is electrically connected to the gate of the first MOS transistor U1 through the third resistor R3; the feedback output terminal of the limit switch unit 3 is electrically connected to the base of the first transistor Q1; the second power supply port of the power input unit 1 is electrically connected to one end of the fifth diode D5; the other end of the fifth diode D5 is electrically connected to the emitter of the first transistor Q1; the seventh resistor R7 is electrically connected between the gate and the source of the first MOS transistor U1; and the eighth resistor R8 is electrically connected between the base and the emitter of the first transistor Q1.
[0049] The collector of the second transistor Q2 serves as the drive output terminal of the second current-limiting drive subunit and is electrically connected to the gate of the second MOSFET U2 via the fourth resistor R4. The feedback output terminal of the limit switch unit 3 is electrically connected to the base of the second transistor Q2. The first power supply port of the power input unit 1 is electrically connected to one end of the fourth diode D4, and the other end of the fourth diode D4 is electrically connected to the emitter of the second transistor Q2. The fifth resistor R5 is electrically connected between the gate and the source of the second MOSFET U2, and the ninth resistor R9 is electrically connected between the base and the emitter of the second transistor Q2.
[0050] In one possible implementation, the limit switch unit 3 includes a left limit switch SW1 subunit and a right limit switch SW2 subunit;
[0051] Wherein, the power supply input terminal of the left travel switch SW1 subunit is electrically connected to the first power supply port of the power input unit 1, and the feedback output terminal of the left travel switch SW1 subunit is electrically connected to the base of the first transistor Q1;
[0052] The power supply input terminal of the right limit switch SW2 subunit is electrically connected to the second power supply port of the power input unit 1, and the feedback output terminal of the right limit switch SW2 subunit is electrically connected to the base of the second transistor Q2.
[0053] In one possible implementation, the left limit switch SW1 subunit includes a left limit switch SW1, a first resistor R1 and a first diode D1, and the right limit switch SW2 subunit includes a right limit switch SW2, a second resistor R2 and a second diode D2;
[0054] Wherein, the first power supply port of the power input unit 1 is electrically connected to one end of the first diode D1, the other end of the first diode D1 is electrically connected to the power supply input terminal of the left limit switch SW1, and the feedback output terminal of the left limit switch SW1 is electrically connected to the base of the first transistor Q1 after passing through the first resistor R1.
[0055] The second power supply port of the power input unit 1 is electrically connected to one end of the second diode D2, and the other end of the second diode D2 is electrically connected to the power supply input terminal of the right limit switch SW2. The feedback output terminal of the right limit switch SW2 is electrically connected to the base of the second transistor Q2 through the second resistor R2.
[0056] It should be noted that, as Figure 2 As shown, when the film winding motor 5 rotates forward, the first power supply port of the power input unit 1 is connected to +24V (VCC-IN3), and the second power supply port of the power input unit 1 is connected to -24V (VCC-IN2). The +24V is input to the source of the first MOSFET U1, and after passing through the first diode D1, it is directly connected to the normally closed contact of the left limit switch SW1. Then, after being current-limited by the first resistor R1, the level of the base (b) of the first transistor Q1 is pulled high, and the collector (c) and emitter (e) of the first transistor Q1 are connected. Because the second power supply port of the power input unit 1 is connected to -24V through the fifth diode D5 to the emitter (e) of the first transistor Q1, after the level of the base (b) of the first transistor Q1 is pulled high, the emitter of the first transistor Q1 is connected. When the (e) terminal is low, it also pulls down the gate level of the first MOSFET U1, making the source and drain of the first MOSFET U1 conduct, so that the drain of the first MOSFET U1 receives a +24V voltage, which supplies the "M+" terminal of the film winding motor 5; the second power supply port of the power input unit 1 receives -24V, which is forward-biased after passing through the damping diode inside the second MOSFET U2 and outputs directly, so the "M-" terminal of the film winding motor 5 receives a -24V power supply. At this time, the film winding motor 5 is powered on and starts to rotate forward. When the cam of the left stroke of the film winding motor 5 reaches the position, it triggers the left stroke switch SW1, the base (b) of the first transistor Q1 turns low, the gate level of the first MOSFET U1 is pulled high, the source and drain of the first MOSFET U1 are disconnected, the film winding motor 5 is de-energized, and the forward rotation stops.
[0057] Correspondingly, when the film winding motor 5 reverses, the first power supply port of the power input unit 1 is connected to -24V (VCC-IN3), and the second power supply port of the power input unit 1 is connected to +24V (VCC-IN2). After passing through the internal damping diode of the first MOSFET U1, the -24V is forward-biased and directly output, so the "M+" terminal of the film winding motor 5 receives the -24V power supply. The second power supply port of the power input unit 1, connected to +24V, inputs the source of the second MOSFET U2, and then directly connects to the normally closed contact of the left limit switch SW1 through the second diode D2. The current is then limited by the second resistor R2 to control the second and third MOSFETs. When the base (b) of transistor Q2 is pulled high, the collector (c) and emitter (e) of the second transistor Q2 are turned on. Since the first power supply port of the power input unit 1 is connected to -24V through the fourth diode D4 to the emitter (e) of the second transistor Q2, after the base (b) of the second transistor Q2 is pulled high, the emitter (e) of the first transistor Q1 is at a low level, which also pulls the gate level of the second MOSFET U2 low. The source and drain of the second MOSFET U2 are turned on, so that the drain of the second MOSFET U2 receives a +24V voltage, which is supplied to the "M-" terminal of the winding motor 5. The first power supply port of the power input unit 1 is supplied with -24V. After passing through the internal damping diode of the second MOSFET U2, it is forward-biased and directly outputs power. The "M-" terminal of the film winding motor 5 then receives +24V power. At this time, the film winding motor 5 is powered on and begins to reverse. When the right travel cam of the film winding motor 5 reaches its position, it triggers the left travel switch SW2. The base (b-terminal) of the second transistor Q2 goes low, the gate level of the second MOSFET U2 goes high, and the source and drain of the second MOSFET U2 are disconnected. The film winding motor 5 is de-energized and stops reversing.
[0058] In one possible implementation, the AC isolation unit 4 includes a four-pin connector CN1, a first capacitor C1, a first rectifier bridge D3, and a first relay K1;
[0059] Wherein, the power supply input terminal of the first relay K1 is electrically connected to the power supply port of the power input unit 1, and the normally closed contact of the first relay K1 serves as the isolation power supply output terminal of the AC isolation unit 4, which is electrically connected to the power supply input terminals of the MOS transistor control unit 2 and the limit switch unit 3.
[0060] The coil of the first relay K1 is electrically connected to the AC input terminal of the first rectifier bridge D3. The first DC output terminal of the first rectifier bridge D3 is electrically connected to one end of the first capacitor C1. The other end of the first capacitor C1 is electrically connected to the first pin of the four-pin connector CN1. The second DC output terminal of the first rectifier bridge D3 is electrically connected to the second pin of the four-pin connector CN1. The third and fourth pins of the four-pin connector CN1 serve as the output terminals of the AC isolation unit 4 and are electrically connected to the input terminal of the film winding motor 5.
[0061] The first pin of the four-pin connector CN1 is also electrically connected to the first relay K1, and the second pin of the four-pin connector CN1 is also electrically connected to the power supply port of the power input unit 1.
[0062] In one possible implementation, the AC isolation unit 4 further includes a sixth resistor R6 and an AC alarm indicator LED1;
[0063] The power supply port of the power input unit 1 and the common terminal of the second pin of the four-pin connector CN1 are electrically connected to one end of the AC alarm indicator LED1 through the sixth resistor R6, and the other end of the AC alarm indicator LED1 is electrically connected to the first relay K1.
[0064] It should be noted that when there is AC power at the first power supply port and the second power supply port of the power input unit 1, the first capacitor C1 in the AC isolation unit 4 is directly turned on. After being rectified by the first rectifier bridge D2, it is converted into DC output to power the coil of the first relay K1. The first relay K1 is energized, and the normally closed contact of the first relay K1 is opened, so that the power input unit 1 is disconnected from the MOS transistor control unit 2 and the limit switch unit 3. This is to prevent the AC power from being rectified by the damping diode of the first MOS transistor U1 or the first MOS transistor U2 and converted into DC power, which would cause the limit switch of the film winding motor 5 to fail and prevent the film winding motor 5 from stopping.
[0065] In one possible implementation, the first relay K1 is a relay of model HF41F / 12-ZS.
[0066] It should be noted that the HF41F / 12-ZS model relay is compact in size, has a long mechanical and electrical life, and can work stably even in harsh environments. Its contacts have strong load capacity and a wide switching current and voltage range, making it very suitable for the control circuit in this embodiment, and meeting the requirements of miniaturization and stability of the overall circuit.
[0067] Finally, it should be noted that the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.
Claims
1. A MOS transistor travel control circuit with AC isolation function, characterized in that, include: Power input unit (1), MOS transistor control unit (2), limit switch unit (3) and AC isolation unit (4); The power supply port of the power input unit (1) is electrically connected to the power supply input terminal of the AC isolation unit (4). The isolation power supply output terminal of the AC isolation unit (4) is electrically connected to the power supply input terminals of the MOS transistor control unit (2) and the limit switch unit (3). The feedback output terminal of the limit switch unit (3) is electrically connected to the feedback input terminal of the MOS transistor control unit (2). The control signal output terminal of the MOS transistor control unit (2) is electrically connected to the controlled input terminal of the film winding motor (5). The output terminal of the AC isolation unit (4) is electrically connected to the input terminal of the film winding motor (5).
2. The MOS transistor travel control circuit with AC isolation function according to claim 1, characterized in that, The MOS transistor control unit (2) includes a first MOS transistor (U1), a second MOS transistor (U2), a first current-limiting drive subunit, and a second current-limiting drive subunit; Wherein, the source of the first MOS transistor (U1) is electrically connected to the first power supply port of the power input unit (1), the source of the second MOS transistor (U2) is electrically connected to the second power supply port of the power input unit (1), the gate of the first MOS transistor (U1) is electrically connected to the drive output terminal of the first current limiting drive subunit, the gate of the second MOS transistor (U2) is electrically connected to the drive output terminal of the second current limiting drive subunit, the drain of the first MOS transistor (U1) is electrically connected to the first controlled input terminal of the winding motor (5), and the drain of the second MOS transistor (U2) is electrically connected to the second controlled input terminal of the winding motor (5); The input terminals of the first current limiting drive subunit and the second current limiting drive subunit serve as the feedback input terminals of the MOS transistor control unit (2) and are electrically connected to the feedback output terminal of the limit switch unit (3).
3. The MOS transistor travel control circuit with AC isolation function according to claim 2, characterized in that, The first current-limiting drive subunit includes a first transistor (Q1), a third resistor (R3), a seventh resistor (R7), an eighth resistor (R8), and a fifth diode (D5). The second current-limiting drive subunit includes a second transistor (Q2), a fourth resistor (R4), a fifth resistor (R5), a ninth resistor (R9), and a fourth diode (D4). The collector of the first transistor (Q1) serves as the drive output terminal of the first current-limiting drive subunit and is electrically connected to the gate of the first MOS transistor (U1) via the third resistor (R3). The feedback output terminal of the limit switch unit (3) is electrically connected to the base of the first transistor (Q1). The second power supply port of the power input unit (1) is electrically connected to one end of the fifth diode (D5), and the other end of the fifth diode (D5) is electrically connected to the emitter of the first transistor (Q1). The seventh resistor (R7) is electrically connected between the gate and the source of the first MOS transistor (U1), and the eighth resistor (R8) is electrically connected between the base and the emitter of the first transistor (Q1). The collector of the second transistor (Q2) serves as the drive output terminal of the second current-limiting drive subunit and is electrically connected to the gate of the second MOS transistor (U2) via the fourth resistor (R4). The feedback output terminal of the limit switch unit (3) is electrically connected to the base of the second transistor (Q2). The first power supply port of the power input unit (1) is electrically connected to one end of the fourth diode (D4), and the other end of the fourth diode (D4) is electrically connected to the emitter of the second transistor (Q2). The fifth resistor (R5) is electrically connected between the gate and the source of the second MOS transistor (U2), and the ninth resistor (R9) is electrically connected between the base and the emitter of the second transistor (Q2).
4. The MOS transistor travel control circuit with AC isolation function according to claim 3, characterized in that, The limit switch unit (3) includes a left limit switch (SW1) subunit and a right limit switch (SW2) subunit; The power supply input terminal of the left travel switch (SW1) subunit is electrically connected to the first power supply port of the power input unit (1), and the feedback output terminal of the left travel switch (SW1) subunit is electrically connected to the base of the first transistor (Q1). The power input terminal of the right limit switch (SW2) subunit is electrically connected to the second power supply port of the power input unit (1), and the feedback output terminal of the right limit switch (SW2) subunit is electrically connected to the base of the second transistor (Q2).
5. The MOS transistor travel control circuit with AC isolation function according to claim 4, characterized in that, The left limit switch (SW1) subunit includes a left limit switch (SW1), a first resistor (R1) and a first diode (D1), and the right limit switch (SW2) subunit includes a right limit switch (SW2), a second resistor (R2) and a second diode (D2). Wherein, the first power supply port of the power input unit (1) is electrically connected to one end of the first diode (D1), the other end of the first diode (D1) is electrically connected to the power supply input terminal of the left limit switch (SW1), and the feedback output terminal of the left limit switch (SW1) is electrically connected to the base of the first transistor (Q1) after passing through the first resistor (R1). The second power supply port of the power input unit (1) is electrically connected to one end of the second diode (D2), and the other end of the second diode (D2) is electrically connected to the power supply input terminal of the right limit switch (SW2). The feedback output terminal of the right limit switch (SW2) is electrically connected to the base of the second transistor (Q2) through the second resistor (R2).
6. The MOS transistor travel control circuit with AC isolation function according to claim 1, characterized in that, The AC isolation unit (4) includes a four-pin connector (CN1), a first capacitor (C1), a first rectifier bridge (D3), and a first relay (K1). The power supply input terminal of the first relay (K1) is electrically connected to the power supply port of the power input unit (1), and the normally closed contact of the first relay (K1) serves as the isolation power supply output terminal of the AC isolation unit (4), and is electrically connected to the power supply input terminals of the MOS tube control unit (2) and the limit switch unit (3). The coil of the first relay (K1) is electrically connected to the AC input terminal of the first rectifier bridge (D3), the first DC output terminal of the first rectifier bridge (D3) is electrically connected to one end of the first capacitor (C1), the other end of the first capacitor (C1) is electrically connected to the first pin of the four-pin connector (CN1), the second DC output terminal of the first rectifier bridge (D3) is electrically connected to the second pin of the four-pin connector (CN1), and the third and fourth pins of the four-pin connector (CN1) serve as the output terminals of the AC isolation unit (4) and are electrically connected to the input terminal of the film winding motor (5). The first pin of the four-pin connector (CN1) is also electrically connected to the first relay (K1), and the second pin of the four-pin connector (CN1) is also electrically connected to the power supply port of the power input unit (1).
7. The MOS transistor travel control circuit with AC isolation function according to claim 6, characterized in that, The AC isolation unit (4) also includes a sixth resistor (R6) and an AC alarm indicator (LED1). The power supply port of the power input unit (1) and the common terminal of the second pin of the four-pin connector (CN1) are connected to one end of the AC alarm indicator (LED1) through the sixth resistor (R6), and the other end of the AC alarm indicator (LED1) is connected to the first relay (K1).
8. The MOS transistor travel control circuit with AC isolation function according to claim 6, characterized in that, The first relay (K1) is a relay of model HF41F / 12-ZS.