Coil driving circuit and contactor system

Abstract

The utility model provides a coil driving circuit and a contactor system. The coil driving circuit comprises a master control switch, a self-driving unit and a control unit. The first access end of the main control switch is used for being electrically connected with the output end of the coil, the second access end of the main control switch is grounded, the controlled end of the main control switch is electrically connected with the output end of the self-driving unit and the output end of the control unit, and the input end of the self-driving unit is used for being electrically connected with the input end of the coil; the self-driving unit is used for driving the main control switch to be switched on when the input end of the self-driving unit and the coil are connected to a power supply together under the condition that the control unit does not work. According to the utility model, the self-driving unit is arranged, and the self-driving unit and the coil can be connected with the power supply together, so that the self-driving unit can directly drive the main control switch according to the power supply connected with the coil together when the coil is electrified so as to control the conduction of the main control switch, the process does not need the participation of a control unit, and the lag time is greatly reduced; the purpose of real-time control of products such as the contactor is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to contactor technical field, concretely relates to a coil drive circuit and contactor system. BACKGROUND

[0002] The contactor is a kind of electrical switch device, for controlling the on-off of circuit. It is usually composed of coil and contact. Coil is the control part of contactor, when current is applied through coil, magnetic field is generated, so that contact is actuated.

[0003] The coil of the intelligent contactor on sale in the market is divided into two kinds of alternating current and direct current, and its control mode is that, after power-on, control system power is established first, then closing, leading to that external control signal is given to main circuit attraction and has long time lag, and the turn-off of bidirectional thyristor scheme also has additional delay of most 10MS because of zero-crossing turn-off characteristics, which is contrary to the original intention of instant control of contactor product. INVENTION CONTENTS

[0004] In view of the deficiencies in the prior art, the utility model provides a coil drive circuit and contactor system.

[0005] In a first aspect, in one embodiment, the utility model provides a coil drive circuit, and the coil drive circuit includes master control switch, self-driving unit and control unit;

[0006] The first access end of master control switch is used to be electrically connected with the output end of coil, the second access end of master control switch is grounded, the controlled end of master control switch is electrically connected with the output end of self-driving unit and the output end of control unit respectively, and the input end of self-driving unit is used to be electrically connected with the input end of coil;

[0007] When the input end of self-driving unit is connected with coil and connected with power supply, master control switch is driven to conduct in the case where control unit does not work.

[0008] In one embodiment, master control switch includes MOS tube;

[0009] The drain of MOS tube is electrically connected with the output end of coil, the gate of MOS tube is electrically connected with the output end of self-driving unit and the first output end of control unit respectively, and the source of MOS tube and the second output end of control unit are grounded respectively;

[0010] When control unit works, whether the gate and source of MOS tube are short-circuited is controlled according to the control signal accessed.

[0011] In one embodiment, control unit includes photoelectric coupler and triode;

[0012] The anode of the light emitting diode in the optocoupler is connected to a working voltage, the cathode of the light emitting diode in the optocoupler is electrically connected to the collector of the transistor, the emitter of the transistor is grounded, the base of the transistor is used for connecting a control signal, the collector of the phototransistor in the optocoupler is electrically connected to the gate of the MOS tube, and the emitter of the phototransistor in the optocoupler is electrically connected to the source of the MOS tube.

[0013] In one embodiment, the base of the transistor is also electrically connected to the anode of the light emitting diode in the optocoupler.

[0014] In one embodiment, the self-driving unit comprises a first voltage dividing resistor and a second voltage dividing resistor.

[0015] The first end of the first voltage dividing resistor is used for being electrically connected to the input end of the coil to connect to a direct current power supply, the second end of the first voltage dividing resistor is electrically connected to the first end of the second voltage dividing resistor and the gate of the MOS tube, and the second end of the second voltage dividing resistor is electrically connected to the source of the MOS tube.

[0016] In one embodiment, the self-driving unit further comprises a rectifier diode.

[0017] The anode of the rectifier diode is used for being electrically connected to the input end of the coil to connect to an alternating current power supply, and the cathode of the rectifier diode is electrically connected to the first end of the first voltage dividing resistor.

[0018] In one embodiment, the coil driving circuit further comprises a voltage stabilizing diode.

[0019] The cathode of the voltage stabilizing diode is respectively electrically connected to the gate of the MOS tube and the first end of the second voltage dividing resistor, and the anode of the voltage stabilizing diode is respectively electrically connected to the source of the MOS tube and the second end of the second voltage dividing resistor.

[0020] In one embodiment, the coil driving circuit further comprises a bidirectional TVS tube.

[0021] The first anode of the bidirectional TVS tube is electrically connected to the drain of the MOS tube, and the second anode of the bidirectional TVS tube is electrically connected to the source of the MOS tube.

[0022] In one embodiment, the coil driving circuit further comprises a rectifier bridge.

[0023] The input end of the rectifier bridge is electrically connected to the output end of the coil, and the output end of the rectifier bridge is electrically connected to the drain of the MOS tube.

[0024] In a second aspect, in one embodiment, the utility model provides a contactor system, the contactor system comprises a coil and the coil driving circuit in any one of the above embodiments.

[0025] Through the coil driving circuit and the contactor system, the self-driving unit is arranged, and the self-driving unit can be connected with the coil to the power supply, so that the self-driving unit can directly drive the main control switch according to the power supply connected with the coil when the coil is powered on, to control the main control switch to be turned on, and the process does not need the participation of the control unit, greatly reduces the lag time, and realizes the purpose of instant control of the contactor and the like. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0027] Figure 1 It is a structure schematic diagram of the coil driving circuit in one embodiment of the present application.

[0028] Figure 2 It is a structure schematic diagram of the coil driving circuit in one embodiment of the present application.

[0029] Figure 3 It is a specific circuit implementation schematic diagram of the coil driving circuit in one embodiment of the present application.

[0030] Figure 4 It is a specific circuit implementation schematic diagram of the coil driving circuit containing the pull-up resistor R15 in one embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0032] In the description of the utility model, it is understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model. In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more than two, unless otherwise explicitly specified. In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration". Any embodiment described as "exemplary" in the present application is not necessarily construed as being more preferred or advantageous than other embodiments. The following description is given in order to enable any person skilled in the art to implement and use the utility model. In the following description, details are listed for the purpose of explanation. It should be understood that those skilled in the art can realize the utility model without using these specific details. In other examples, well-known structures and processes will not be described in detail in order to avoid unnecessary details making the description of the utility model obscure. Therefore, the utility model is not intended to be limited to the embodiments shown, but is consistent with the broadest scope consistent with the principles and characteristics disclosed in the present application.

[0033] In one embodiment, the utility model provides a coil driving circuit, which comprises a master control switch, a self-driving unit and a control unit. Figure 1

[0034] Wherein, the coil can be the coil in the contactor, or the coil in the relay.

[0035] Wherein, the first access end of the master control switch is used for electrical connection with the output end of the coil, the second access end of the master control switch is grounded, the controlled end of the master control switch is respectively electrically connected with the output end of the self-driving unit and the output end of the control unit, and the input end of the self-driving unit is used for electrical connection with the input end of the coil.

[0036] Wherein, the coil is connected in series with the master control switch, the master control switch is used for controlling the on-off of the loop where the coil is located, thereby controlling the power-on and power-off of the coil, and further controlling the switching state of the contactor or the relay.

[0037] ​In the case that the control unit is not working, the input end of the self-driving unit is connected to the power supply together with the coil to drive the main control switch to be turned on.

[0038] The control unit can control the output state of the self-driving unit when working, thereby controlling the switching state of the main control switch. However, when the control unit is not working, the self-driving unit can directly control the main control switch to be turned on according to the power supply connected. That is, when the coil is powered on, the self-driving unit is powered on at the same time, and at this time, there is no need to wait for the control unit to be powered on and to control the main control switch to be turned on. The self-driving unit can directly control the main control switch to be turned on.

[0039] Through the above coil driving circuit, the self-driving unit is arranged, and the self-driving unit can be connected to the power supply together with the coil, so that the self-driving unit can directly drive the main control switch according to the power supply connected together with the coil when the coil is powered on, to control the main control switch to be turned on. This process does not need the participation of the control unit, greatly reduces the lag time, and achieves the purpose of instant control of the contactor and other products.

[0040] As shown in FIG. 1, Figure 2 In one embodiment, the main control switch includes a MOS tube Q1.

[0041] The drain of the MOS tube Q1 is electrically connected to the output end of the coil, the gate of the MOS tube Q1 is electrically connected to the output end of the self-driving unit and the first output end of the control unit respectively, and the source of the MOS tube Q1 and the second output end of the control unit are grounded.

[0042] When the control unit is working, whether the gate and the source of the MOS tube are short-circuited is controlled according to the control signal connected.

[0043] When the self-driving unit is connected to the power supply, it outputs a high level to the MOS tube Q1, thereby driving the MOS tube Q1 to be turned on, and the subsequent control unit can further control the on-off of the MOS tube Q1 by controlling whether the gate and the source of the MOS tube Q1 are short-circuited. Specifically, when the control unit controls the gate and the source of the MOS tube Q1 to be short-circuited, the gate voltage of the MOS tube Q1 is pulled down to the ground, and the MOS tube Q1 is cut off; when the control unit controls the gate and the source of the MOS tube Q1 not to be short-circuited, the gate voltage of the MOS tube Q1 remains as the high level input from the self-driving unit, and the MOS tube Q1 remains to be turned on.

[0044] As shown in FIG. 1, Figure 3 In one embodiment, the control unit includes an optical coupler U2 and a triode Q4.

[0045] The anode of the light emitting diode in the optocoupler U2 is connected to the working voltage (e.g. 12V working voltage) through the pull-up resistor R14, the cathode of the light emitting diode in the optocoupler U2 is electrically connected to the collector of the transistor Q4, the emitter of the transistor Q4 is grounded, the base of the transistor Q4 is used to connect the control signal CTRL, the collector of the photo-sensitive transistor in the optocoupler U2 is electrically connected to the gate of the MOS tube Q1, and the emitter of the photo-sensitive transistor in the optocoupler U2 is electrically connected to the source of the MOS tube Q1.

[0046] When the anode of the light emitting diode in the optocoupler U2 is connected to the 12V working voltage through the pull-up resistor R14, if the host computer is powered on and outputs the high-level control signal CTRL, the base of the transistor Q4 is connected to the high-level control signal CTRL, the transistor Q4 is turned on, and the 12V working voltage can form a current loop through the light emitting diode in the optocoupler U2 and the transistor Q4 and then to the ground, at this time, the light emitting diode in the optocoupler U2 emits light, the photo-sensitive transistor in the optocoupler U2 is turned on, the gate and the source of the MOS tube Q1 are shorted, and the MOS tube Q1 is cut off; if the host computer is not powered on or is powered on but outputs the low-level control signal CTRL, the base of the transistor Q4 is connected to the low-level control signal CTRL, the transistor Q4 is cut off, and the 12V working voltage cannot form a current loop through the light emitting diode in the optocoupler U2 and the transistor Q4 and then to the ground, at this time, the light emitting diode in the optocoupler U2 does not emit light, the photo-sensitive transistor in the optocoupler U2 is cut off, the gate and the source of the MOS tube Q1 are not shorted, and the MOS tube Q1 is turned on.

[0047] It can be seen that when the control signal CTRL is not considered, the MOS tube Q1 is in the on state only when the 12V working voltage is connected, and this control mode can be understood as a "normally closed state mode".

[0048] As shown in Figure 4 In one embodiment, the base of the transistor Q4 is also electrically connected to the anode of the light emitting diode in the optocoupler U2 through the pull-up resistor R15 to connect the working voltage (e.g. 12V working voltage).

[0049] In this embodiment, when the anode of the LED in optocoupler U2 is connected to a 12V operating voltage through pull-up resistor R14, if the host computer is not powered on or is powered on and outputs a high-level control signal CTRL, the base of transistor Q4 is connected to the high-level control signal CTRL, and transistor Q4 conducts. The connected 12V operating voltage can pass through the LED in optocoupler U2 and transistor Q4 in sequence to ground, forming a current loop. At this time, the LED in optocoupler U2 emits light, and the phototransistor in optocoupler U2 conducts. When the gate and source of MOSFET Q1 are shorted, MOSFET Q1 is turned off. If the host computer is powered on but outputs a low-level control signal CTRL, the base of transistor Q4 is connected to the low-level control signal CTRL, transistor Q4 is turned off. The 12V operating voltage cannot pass through the LED in optocoupler U2 and transistor Q4 in sequence to ground to form a current loop. At this time, the LED in optocoupler U2 does not light up, the phototransistor in optocoupler U2 is turned off, the gate and source of MOSFET Q1 are not shorted, and MOSFET Q1 is turned on.

[0050] It can be seen that when the control signal CTRL is not considered, MOSFET Q1 is in the off state when only the 12V operating voltage is connected. This control mode can be understood as the "normally open state mode".

[0051] like Figure 3 or Figure 4 As shown, the control unit also includes a pull-down resistor R18 and a capacitor C7.

[0052] The first end of the pull-down resistor R18 is electrically connected to the base of transistor Q4 and the first end of capacitor C7, respectively, and the second end of the pull-down resistor R18 is electrically connected to the emitter of transistor Q4 and the second end of capacitor C7, respectively.

[0053] Among them, the pull-down resistor R18 serves two purposes: firstly, it acts as the input resistor for transistor Q4, limiting the base current; secondly, it... Figure 4 In addition, the pull-down resistor R18 can also form a voltage divider network with the pull-up resistor R15, which can limit the base voltage.

[0054] Among them, capacitor C7 plays the role of filtering, filtering out high-frequency noise signals to ensure that the base of transistor Q4 has a stable DC bias input.

[0055] like Figure 3 or Figure 4 As shown, in one embodiment, the self-driving unit includes a rectifier diode D2, a first voltage divider resistor (including resistors R3, R4 and R16) and a second voltage divider resistor (including resistor R17).

[0056] Wherein, the anode of the rectifier diode D2 is electrically connected with the input end of the coil L1 and the live wire L through the resistor R1 respectively to access the alternating power supply, the cathode of the rectifier diode D2 is electrically connected with the first end of the resistor R3, the second end of the resistor R3 is electrically connected with the first end of the resistor R4, the second end of the resistor R4 is electrically connected with the first end of the resistor R16, the second end of the resistor R16 is electrically connected with the first end of the resistor R17 and the gate of the MOS tube Q1 respectively, and the second end of the resistor R17 is electrically connected with the source of the MOS tube Q1.

[0057] Wherein, the alternating power supply accessed is rectified by the rectifier diode D2 and is divided by the resistor R3, the resistor R4, the resistor R16 and the resistor R17, and then a high level of appropriate voltage value is provided to the base of the MOS tube Q1 to drive the MOS tube Q1 to be turned on.

[0058] Wherein, when the current is a direct current power supply, the first end of the resistor R3 is directly connected with the direct current power supply, and in this case, the rectifier diode D2 does not need to be set.

[0059] As shown in Figure 3 or Figure 4 in an embodiment, the coil driving circuit further comprises a voltage stabilizing diode ZD1.

[0060] Wherein, the cathode of the voltage stabilizing diode ZD1 is electrically connected with the gate of the MOS tube Q1 and the first end of the resistor R17 respectively, and the anode of the voltage stabilizing diode ZD1 is electrically connected with the source of the MOS tube Q1 and the second end of the resistor R17 respectively.

[0061] Wherein, as mentioned in the above embodiment, the resistor R3, the resistor R4, the resistor R16 and the resistor R17 can provide a high level of appropriate voltage value to the base of the MOS tube Q1 through voltage division, but when the voltage amplitude of the accessed power supply abnormally jumps, it will cause the voltage provided to the gate of the MOS tube Q1 by the resistor R3, the resistor R4, the resistor R16 and the resistor R17 through voltage division to be too high, so it is easy to damage the MOS tube Q1. Therefore, in this embodiment, in view of this situation, the voltage stabilizing diode ZD1 is connected in parallel between the gate and the source of the MOS tube Q1, and when the voltage provided to the gate of the MOS tube Q1 by the resistor R3, the resistor R4, the resistor R16 and the resistor R17 through voltage division is too high, the voltage across the voltage stabilizing diode ZD1 exceeds its voltage stabilizing value, so that the voltage stabilizing diode ZD1 is broken down, thereby leading the large voltage to the ground, and protecting the MOS tube Q1 from being damaged by the large voltage.

[0062] In Figure 3 or Figure 4 , the 12V working voltage accessed by the optocoupler U2 can be converted based on the accessed alternating power supply, and in this case, as long as the system is powered on, the coil L1, the optocoupler U2 in the control unit and the rectifier diode D2 in the self-driving unit are powered on at the same time.

[0063] As shown in Figure 3 or Figure 4 The coil driving circuit further comprises a capacitor C3.

[0064] The first end of the capacitor C3 is electrically connected with the first end of the resistor R17 and the gate of the MOS tube Q1 respectively, and the second end of the capacitor C3 is electrically connected with the second end of the resistor R17 and the source of the MOS tube Q1 respectively.

[0065] The MOS tube Q1 has Miller effect which will affect the performance of the MOS tube Q1. The parallel capacitor C3 between the gate and the source of the MOS tube Q1 can provide a frequency compensation mechanism to solve the Miller effect.

[0066] As shown in Figure 3 or Figure 4 In an embodiment, the coil driving circuit further comprises a bidirectional TVS tube D5.

[0067] The first anode of the bidirectional TVS tube D5 is electrically connected with the drain of the MOS tube Q1, and the second anode of the bidirectional TVS tube D5 is electrically connected with the source of the MOS tube Q1.

[0068] The coil L1 is an inductive load which is easy to generate a high back electromotive force when the current changes suddenly. The high back electromotive force is easy to damage the MOS tube Q1. The bidirectional TVS tube D5 can be turned on when the back electromotive force generated by the coil L1 is too high, so as to protect the MOS tube Q1 from being damaged.

[0069] As shown in Figure 3 or Figure 4 In an embodiment, the coil driving circuit further comprises a capacitor C2, a resistor R2 and a resistor R5.

[0070] The first end of the capacitor C2 is electrically connected with the drain of the MOS tube Q1, the second end of the capacitor C2 is electrically connected with the first end of the resistor R2, the second end of the resistor R2 is electrically connected with the first end of the resistor R5, and the second end of the resistor R5 is electrically connected with the source of the MOS tube Q1.

[0071] The parallel capacitor C2 can provide frequency compensation to offset the influence of the internal capacitance of the MOS tube Q1 on high-frequency signals. The parallel capacitor C2 can also form a feedback loop between the drain and the source of the MOS tube Q1 to stabilize the working state of the circuit through feedback action.

[0072] The resistor R2 and the resistor R5 play a role in limiting current.

[0073] As shown in Figure 3 or Figure 4 In an embodiment, the coil driving circuit further comprises a rectifier bridge D1.

[0074] The first input end of the rectifier bridge D1 is electrically connected with the output end of the coil L1, the second input end of the rectifier bridge D1 is electrically connected with the zero line N, the first output end of the rectifier bridge D1 is electrically connected with the drain of the MOS tube Q1, and the second output end of the rectifier bridge D1 is grounded.

[0075] The MOS tube Q1 is usually used to realize the on-off control of the direct current loop, so when the power source connected with the coil L1 is an alternating current power source, the rectifier bridge D1 can be connected in series between the coil L1 and the MOS tube Q1, so that the alternating current output by the coil L1 is rectified into direct current by the rectifier bridge D1, and then output to the MOS tube Q1, so that the MOS tube Q1 can be used to control the on-off of the direct current loop.

[0076] In other embodiments, a single diode can also be used to realize the rectification between the coil L1 and the MOS tube Q1, but the single diode is half-wave rectification, and the rectifier bridge D1 is full-wave rectification, so the conversion efficiency of the rectifier bridge D1 is relatively high.

[0077] As shown in Figure 3 Or Figure 4 In one embodiment, the coil driving circuit further comprises a pressure-sensitive resistor RV1 and a capacitor C1.

[0078] The pressure-sensitive resistor RV1 plays a role in preventing surges, and when the voltage is lower than the rated voltage of the pressure-sensitive resistor RV1, it behaves as a high resistance value, and only a small current passes through. But when the voltage exceeds the rated voltage of the pressure-sensitive resistor RV1, the resistance value of the pressure-sensitive resistor RV1 rapidly decreases, forming a low-impedance path, so that the overvoltage can flow through it, thereby protecting other circuit elements in the latter stage.

[0079] The capacitor C1 plays a role in filtering.

[0080] In a second aspect, in one embodiment, the utility model provides a contactor system, the contactor system comprises a coil and the coil driving circuit in any of the above embodiments.

[0081] Through the above-mentioned contactor system, the self-driving unit is arranged, and the self-driving unit can be connected with the coil to the power supply, so that the self-driving unit can directly drive the main control switch according to the power supply connected with the coil when the coil is powered on, so as to control the main control switch to be turned on. This process does not require the participation of the control unit, greatly reduces the lag time, and achieves the purpose of instant control of the contactor and other products.

[0082] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the detailed description of other embodiments in the above, which will not be repeated here.

[0083] The coil driving circuit and the contactor system are described in detail above, the principle and the implementation mode of the present application are described by applying specific examples in this paper, the description of the above examples is only used to help understand the method and the core idea of the present application; at the same time, for the skilled in the art, according to the idea of the present application, there will be changes in the specific implementation mode and the application range, and the above is not understood as a limitation of the present application.

[0084] The technical features of the above embodiments can be combined arbitrarily, in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of these technical features does not exist contradictory, it should be considered that it is within the scope of the present application.

Claims

1. A coil drive circuit, characterized by, The coil driving circuit comprises a master switch, a self-driving unit and a control unit; a first access end of the master switch is used for electrically connecting with an output end of the coil, a second access end of the master switch is grounded, a controlled end of the master switch is electrically connected with an output end of the self-driving unit and an output end of the control unit respectively, and an input end of the self-driving unit is used for electrically connecting with an input end of the coil; when the input end of the self-driving unit is connected with the coil to access a power supply, the master switch is driven to be turned on in the case that the control unit does not work.

2. The coil drive circuit of claim 1, wherein The master switch comprises a MOS tube; a drain of the MOS tube is electrically connected with the output end of the coil, a gate of the MOS tube is electrically connected with the output end of the self-driving unit and a first output end of the control unit respectively, and a source of the MOS tube and a second output end of the control unit are grounded respectively; when the control unit works, whether the gate and the source of the MOS tube are short-circuited is controlled according to an accessed control signal.

3. The coil drive circuit of claim 2, wherein, The control unit comprises an optical coupler and a triode; an anode of a light-emitting diode in the optical coupler accesses a working voltage, a cathode of the light-emitting diode in the optical coupler is electrically connected with a collector of the triode, an emitter of the triode is grounded, a base of the triode is used for accessing the control signal, a collector of a photosensitive triode in the optical coupler is electrically connected with the gate of the MOS tube, and an emitter of the photosensitive triode in the optical coupler is electrically connected with the source of the MOS tube.

4. The coil drive circuit of claim 3, wherein The base of the triode is also electrically connected with the anode of the light-emitting diode in the optical coupler.

5. The coil drive circuit of claim 2, wherein, The self-driving unit comprises a first voltage dividing resistor and a second voltage dividing resistor; a first end of the first voltage dividing resistor is used for electrically connecting with the input end of the coil to access a direct-current power supply, a second end of the first voltage dividing resistor is electrically connected with a first end of the second voltage dividing resistor and the gate of the MOS tube, and a second end of the second voltage dividing resistor is electrically connected with the source of the MOS tube.

6. The coil drive circuit of claim 5, wherein, The self-driving unit further comprises a rectifier diode; an anode of the rectifier diode is used for electrically connecting with the input end of the coil to access an alternating-current power supply, and a cathode of the rectifier diode is electrically connected with the first end of the first voltage dividing resistor.

7. The coil drive circuit of claim 5, wherein, The coil driving circuit further comprises a voltage stabilizing diode; a cathode of the voltage stabilizing diode is electrically connected with the gate of the MOS tube and the first end of the second voltage dividing resistor respectively, and an anode of the voltage stabilizing diode is electrically connected with the source of the MOS tube and the second end of the second voltage dividing resistor respectively.

8. The coil drive circuit of claim 2, wherein, The coil driving circuit further comprises a bidirectional TVS tube; a first anode of the bidirectional TVS tube is electrically connected with the drain of the MOS tube, and a second anode of the bidirectional TVS tube is electrically connected with the source of the MOS tube.

9. The coil drive circuit of claim 2, wherein, The coil driving circuit further comprises a rectifier bridge; an input end of the rectifier bridge is electrically connected with the output end of the coil, and an output end of the rectifier bridge is electrically connected with the drain of the MOS tube.

10. A contactor system characterized by, The contactor system comprises a coil and the coil driving circuit according to any one of claims 1 to 9.

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