Relay drive control circuit

Abstract

The utility model relates to the technical field of relay control, and provides a relay drive control circuit, which comprises an input control module, a voltage division control module, a comparator, a first capacitor, a first triode and a second triode, the control end of the input control module is connected with the first input end of the comparator and the base electrode of the second triode. A second input end of the comparator is connected with a rated voltage signal end through the voltage division control module, and an output end of the comparator is connected with a base electrode of the first triode; one end of the first capacitor is connected with the first input end of the comparator and the other end is grounded; an emitter of the first triode is connected with a rated voltage signal end, and a collector of the first triode is connected with a first contact of a relay to be driven and a holding voltage signal end; the emitter of the second triode is connected with the second contact of the relay to be driven, and the collector of the second triode is grounded. According to the circuit, the EMC problem is avoided, a plurality of electrolytic capacitors do not need to be connected in parallel, and the circuit cost is relatively low.

Description

Technical Field

[0001] The utility model relates to the technical field of relay control, in particular to a relay drive control circuit. Background Art

[0002] Electromagnetic relays are widely used in power electronic control circuits. In the existing electromagnetic relay control circuits, the rated voltage of the coil is generally used to turn on the relay, and after a period of time, it is switched to a relatively low holding voltage to maintain the suction state of the relay, thereby reducing the risk of the coil being burned out due to the relay being sucked by a high voltage for a long time. At present, the opening and holding of high-power relays are mainly divided into two methods: 1. First, use a large voltage to turn on the relay, and then use a pulse width modulation (PWM) signal to be equivalent to a low voltage mode to maintain the suction state of the relay; 2. Use a microcontroller unit (MCU) to control a MOS (Metal-Oxide-Semiconductor) tube, and connect multiple large capacitors in parallel at the power supply end for support.

[0003] In the first method, using a PWM signal to be equivalent to a lower holding voltage is likely to cause electromagnetic compatibility (EMC) interference during signal transmission, resulting in the problem that the EMC test of the device cannot pass. In the second method, multiple electrolytic capacitors are required, which will result in a relatively high cost. Therefore, how to achieve low-cost drive control of the relay and prevent EMC interference is a technical problem that needs to be solved urgently at present. Summary of the Utility Model

[0004] The utility model provides a relay drive control circuit to solve the above-mentioned technical problems in the prior art.

[0005] The utility model provides a relay drive control circuit, including: an input control module, a voltage division control module, a comparator, a first capacitor, a first triode, and a second triode.

[0006] The control end of the input control module is connected to the first input end of the comparator and the base of the second triode, and is used to control the first input end of the comparator and the base of the second triode to be connected to the rated voltage signal end or grounded.

[0007] The second input end of the comparator is connected to the rated voltage signal end through the voltage division control module, and the output end of the comparator is connected to the base of the first triode.

[0008] One end of the first capacitor is connected to the first input end of the comparator, and the other end is grounded.

[0009] The emitter of the first triode is connected to the rated voltage signal terminal, and the collector of the first triode is connected to the first contact of the relay to be driven and the holding voltage signal terminal.

[0010] The emitter of the second triode is connected to the second contact of the relay to be driven, and the collector of the second triode is grounded.

[0011] According to a relay driving control circuit provided by the present invention, the voltage dividing control module includes: a first resistor, a second resistor, and a second capacitor.

[0012] One end of the first resistor is connected to the second input terminal of the comparator, and the other end is grounded.

[0013] One end of the second resistor is connected to the second input terminal of the comparator, and the other end is connected to the rated voltage signal terminal.

[0014] One end of the second capacitor is connected to the second input terminal of the comparator, and the other end is grounded.

[0015] According to a relay driving control circuit provided by the present invention, it further includes: a voltage building control module, and the voltage building control module includes: a third resistor, and the first input terminal of the comparator is connected to the control terminal of the input control module through the third resistor.

[0016] According to a relay driving control circuit provided by the present invention, the voltage building control module further includes: a first diode and a fourth resistor with a resistance value smaller than that of the third resistor.

[0017] One end of the fourth resistor is connected to the first input terminal of the comparator, the other end is connected to the anode of the first diode, and the cathode of the first diode is connected to the control terminal of the input control module to form a series branch including the fourth resistor and the first diode, and the third resistor is connected in parallel with the series branch.

[0018] According to a relay driving control circuit provided by the present invention, it further includes: a third capacitor, one end of the third capacitor is connected to the collector of the first triode, and the other end is grounded.

[0019] According to a relay driving control circuit provided by the present invention, it further includes: a second diode, the anode of the second diode is connected to the emitter of the second triode, and the cathode is connected to the collector of the first triode.

[0020] According to a relay driving control circuit provided by the present invention, it further includes: a third diode, the anode of the third diode is connected to the holding voltage signal terminal, and the cathode is connected to the collector of the first triode.

[0021] A relay driving control circuit provided by the present utility model further includes: a fifth resistor, a sixth resistor, and a seventh resistor.

[0022] The emitter of the first triode is connected to the rated voltage signal terminal through the fifth resistor.

[0023] The base of the first triode is connected to the output terminal of the comparator through the sixth resistor.

[0024] One end of the seventh resistor is connected to the output terminal of the comparator, and the other end is connected to the rated voltage signal terminal.

[0025] A relay driving control circuit provided by the present utility model further includes: an eighth resistor and a ninth resistor.

[0026] The base of the second triode is connected to the control terminal of the input control module through the eighth resistor.

[0027] One end of the ninth resistor is connected to the base of the second triode, and the other end is connected to the collector of the second triode.

[0028] A relay driving control circuit provided by the present utility model, the input control module includes: a microcontroller and an optocoupler. The anode of the light-emitting diode on the primary side of the optocoupler is connected to the control voltage signal terminal, the cathode of the light-emitting diode is connected to the output terminal of the microcontroller, the emitter of the photosensitive triode on the secondary side of the optocoupler is connected to the rated voltage signal terminal, the collector of the photosensitive triode is grounded, and the emitter of the photosensitive triode serves as the control terminal of the input control module.

[0029] The relay driving control circuit provided by the present utility model, through the above circuit structure, realizes the normal opening of the relay to be driven, and there is no risk of burning out the relay, avoids the EMC problem caused by using a PWM signal to equivalently represent a lower holding voltage, and does not require multiple electrolytic capacitors to be connected in parallel, and the circuit cost is relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 is one of the schematic diagrams of the relay driving control circuit structure provided in the related prior art.

[0032] Figure 2It is the second schematic diagram of the relay drive control circuit structure provided in the existing related technologies.

[0033] Figure 3 It is the schematic diagram of the relay drive control circuit structure provided by the present utility model.

[0034] Figure 4 It is the schematic diagram of the working principle of the relay drive control circuit provided by the present utility model. Specific embodiments

[0035] To make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions in the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0036] It is noted in the relay specification: To turn on the relay, a relatively high rated voltage is required and needs to be maintained for a period of time, and then switched to a lower holding voltage. The relay cannot work at the rated voltage for a long time, otherwise there will be a risk of burning out the relay.

[0037] Based on this, in the existing related technologies, as Figure 1 shown, the controller U1 first outputs a high level, the triode Q1 conducts, and the relay RLB1 is attracted. After a period of time, the controller U1 outputs a PWM signal, which is equivalent to a lower holding voltage to maintain the attracted state of the relay. However, using the PWM signal to drive the triode Q1 easily brings EMC problems to the circuit, resulting in the product failing to pass the certification. As Figure 2 shown, in another relay drive control circuit, the controller U1 first outputs a high level, the triode Q1 conducts, and thus the relay RLB1 is attracted. Since the relay needs to be maintained at the rated voltage (such as VCC1) for a period of time and then switched to a lower holding voltage (such as VCC2) when it is attracted, multiple electrolytic capacitors (C1~C3) need to be connected in parallel at VCC1 to allow the relay to maintain at the voltage of VCC1 for a period of time and then switch to the holding voltage VCC2. Otherwise, the phenomenon that the relay fails to be attracted will occur. This solution requires multiple electrolytic capacitors to be connected in parallel, resulting in a high circuit cost.

[0038] To solve the above existing technical problems, this embodiment provides a relay drive control circuit, and the circuit structure is as Figure 3 shown, including: an input control module, a comparator U2A, a first capacitor C1, a first triode Q1 and a second triode Q2.

[0039] The control terminal of the input control module is connected to the first input terminal of comparator U2A (for example: Figure 3 pin 3 of comparator U2A in Figure 3 , that is, the positive input terminal) and the base of the second triode Q2, and is used to control the first input terminal of comparator U2A and the base of the second triode Q2 to be connected to the rated voltage signal terminal VCC1 or grounded. The control terminal of the input control module can be understood as a switch. According to different inputs of the input control module, through the on and off of the switch, the first input terminal of comparator U2A and the base of the second triode Q2 are both connected to the rated voltage signal terminal VCC1 or grounded. It should be noted that: the rated voltage signal terminal VCC1 here only means that this voltage signal terminal can provide the rated voltage for the relay to be driven to make it attract, and does not mean that the voltage of the rated voltage signal terminal VCC1 must be the rated voltage.

[0040] The second input terminal of comparator U2A (for example: Figure 3 pin 2 of comparator U2A in Figure 3 , that is, the negative input terminal) is connected to the rated voltage signal terminal VCC1 through a voltage division control module, and the output terminal of comparator U2A is connected to the base of the first triode Q1. Among them, the voltage division control module is used for voltage division, so that the voltage of the second input terminal of comparator U2A is less than the voltage of the rated voltage signal terminal VCC1. Of course, the power supply terminal V of comparator U2A can be connected to the rated voltage signal terminal VCC1, and the ground terminal G of comparator U2A is grounded.

[0041] One end of the first capacitor C1 is connected to the first input terminal of comparator U2A, and the other end is grounded.

[0042] The emitter of the first triode Q1 is connected to the rated voltage signal terminal VCC1, and the collector of the first triode Q1 is connected to the first contact of the relay to be driven RLB ( Figure 3 contact 1 of the relay to be driven RLB in Figure 3 ) and the holding voltage signal terminal VCC2, that is, the first contact of the relay to be driven RLB is also connected to the holding voltage signal terminal VCC2.

[0043] The emitter of the second triode Q2 is connected to the second contact of the relay to be driven ( Figure 3 contact 2 of the relay to be driven RLB in Figure 3 ), the collector of the second triode Q2 is grounded, and the second triode Q2 can be an NPN-type triode, that is, it conducts when the level is high and turns off when the level is low.

[0044] Such as Figure 3As shown in the figure, the working principle of the relay drive control circuit in this embodiment is as follows: When the control terminal of the input control module controls the first input terminal of comparator U2A and the base of the second triode Q2 to be connected to the rated voltage signal terminal VCC1, point A is at a high level, the second triode Q2 conducts, and the second contact (contact No. 2) of the relay to be driven RLB is grounded. Since the second input terminal of comparator U2A is connected to the rated voltage signal terminal VCC1 through a voltage division control circuit, at this time, the voltage at the second input terminal of comparator U2A, that is, point C, is a fixed high voltage. At this time, although the first input terminal of comparator U2A is also connected to the rated voltage signal terminal VCC1, due to the effect of the first capacitor C1, the voltage at the first input terminal of comparator U2A, that is, point B, will not reach VCC1 directly, but will approach or even reach the voltage of VCC1 after a period of time starting from 0. During the rising process of the voltage at point B from small to large, when the voltage at point B is less than the voltage at point C, according to the characteristics of comparator U2A, U2A outputs a low level. The first triode Q1 can be a PNP-type triode, and at this time it is saturated and conducts, and the first contact (contact No. 1) of the relay to be driven RLB is connected to VCC1, then the relay to be driven RLB is attracted. As the voltage at point B gradually rises to be greater than the voltage at point C, according to the characteristics of comparator U2A, U2A outputs a high level, and the first triode Q1 is completely cut off at this time. The first contact of the relay to be driven RLB is disconnected from VCC1 and is powered by the holding voltage signal terminal VCC2 to maintain the attracted state of the relay to be driven RLB, thus realizing the normal opening of the relay to be driven and there is no risk of burning out the relay. When the control terminal of the input control module controls the first input terminal of comparator U2A and the base of the second triode Q2 to be grounded, point A is at a low level, the second triode Q2 is cut off, and the second contact (contact No. 2) of the relay to be driven RLB is no longer connected to the ground, that is, it is floating, and the relay to be driven RLB is disconnected.

[0045] It should be noted that: The rising speed of the voltage at point B can be adjusted by adjusting the size of the first capacitor C1, that is, adjusting the length of the time period during which a relatively high rated voltage is required to keep the relay open. In addition, as Figure 3 shown, if point C is connected to IN+ of comparator U2A and point B is connected to IN- of comparator U2A, then the first triode Q is an NPN-type triode.

[0046] The relay drive control circuit in this embodiment adopts the above circuit structure, realizing the normal opening of the relay to be driven and there is no risk of burning out the relay, avoiding the EMC problem caused by using a PWM signal to equivalently represent a relatively low holding voltage, and moreover, there is no need to connect multiple electrolytic capacitors in parallel, and the circuit cost is relatively low.

[0047] In some embodiments, such as Figure 3As shown, the voltage division control module includes: a first resistor R1, a second resistor R2, and a second capacitor C2. One end of the first resistor R1 is connected to the second input terminal of the comparator U2A, and the other end is grounded. One end of the second resistor R2 is connected to the second input terminal of the comparator U2A, and the other end is connected to the rated voltage signal terminal VCC1. One end of the second capacitor C2 is connected to the second input terminal of the comparator U2A, and the other end is grounded, that is, the second capacitor C2 is in parallel with the first resistor R1. Based on the circuit structure of this voltage division control module, the voltage at point C is: Vcc1×r1 / (r1 + r2), where Vcc1 represents the voltage of the rated voltage signal terminal VCC1, and r1 and r2 respectively represent the resistance values of the first resistor R1 and the second resistor R2. By changing the resistance values of the first resistor R1 and the second resistor R2 and the capacitance value of the first capacitor C1, the length of the time period during which a higher rated voltage is required to keep the relay on can be adjusted. With multi-parameter adjustment, it is more flexible to adjust and select components, and the cost is low and it is easy to implement.

[0048] In some embodiments, the relay drive control circuit further includes: a voltage build-up control module. The voltage build-up control module includes: a third resistor R3. The first input terminal of the comparator U2A is connected to the control terminal of the input control module through the third resistor R3. Specifically, one end of the third resistor R3 is connected to the first input terminal of the comparator U2A, and the other end is connected to the control terminal of the input control module. Due to the third resistor R3, a gentle voltage rising curve will be formed at the first input terminal of the comparator U2A. That is, by adjusting the resistance value of the third resistor R3, the rising speed of the voltage at point B can be adjusted, thereby adjusting the time when the comparator U2A outputs a low level, that is, adjusting the time during which a higher rated voltage is required to keep the relay on, and it is more convenient to adjust the third resistor R3 than to adjust the first resistor C1.

[0049] In some embodiments, the voltage build-up control module further includes: a first diode D1 and a fourth resistor R4 with a resistance value smaller than that of the third resistor R3. One end of the fourth resistor R4 is connected to the first input terminal of the comparator U2A, and the other end is connected to the anode of the first diode D1. The cathode of the first diode D1 is connected to the control terminal of the input control module to form a series branch including the fourth resistor R4 and the first diode D1, and the third resistor R3 is in parallel with the series branch. Due to the function of the first diode D1, during the voltage build-up process at point B, the forced current flows from the branch of the third resistor R3 to the first input terminal of the comparator U2A, thereby forming a gentle voltage rising curve at point B. And because the resistance value of the fourth resistor R4 is smaller than that of the third resistor R3 (for example: the resistance value of the fourth resistor R4 is 1K ohm, and the resistance value of the third resistor R3 is 100K ohm), when the first input terminal of the comparator U2A is grounded, the first input terminal of the comparator U2A can quickly return to a low level, avoiding oscillation at the critical point.

[0050] In some embodiments, the relay drive control circuit further includes: a third capacitor C3, one end of the third capacitor C3 is connected to the collector of the first triode Q1, and the other end is grounded. Specifically, the third capacitor C3 may be an electrolytic capacitor, the positive electrode end of the third capacitor C3 is connected to the collector of the first triode Q1, and the negative electrode end is grounded. The third capacitor C3 is used when the first and second contacts of the relay to be driven RLB are closed instantaneously and require a large voltage and current. The electrolytic capacitor of the third capacitor C3 can achieve a large capacitance, so as to keep the voltage of VCC1 stable when the relay is closed.

[0051] In some embodiments, the relay drive control circuit further includes: a second diode D2, the anode of the second diode D2 is connected to the emitter of the second triode Q2, and the cathode is connected to the collector of the first triode Q1, that is, the anode of the second diode D2 is connected to the second contact of the relay to be driven RLB, and the cathode is connected to the first contact of the relay to be driven RLB, and is used to provide a low-impedance path, so that the energy stored in the coil can be safely released through this path when powered off, rather than reversely impacting other components in the circuit.

[0052] In some embodiments, the relay drive control circuit further includes: a third diode D3, the anode of the third diode D3 is connected to the hold voltage signal terminal, and the cathode is connected to the collector of the first triode Q1. The third diode D3 is used to prevent current from flowing into the hold voltage signal terminal VCC2 when the first triode Q1 is turned on.

[0053] In some embodiments, the relay drive control circuit further includes: a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The emitter of the first triode Q1 is connected to the rated voltage signal terminal VCC1 through the fifth resistor R5, that is, one end of the fifth resistor R5 is connected to the emitter of the first triode Q1, and the other end is connected to the rated voltage signal terminal; the base of the first triode Q1 is connected to the output terminal of the comparator U2A through the sixth resistor R6, that is, one end of the sixth resistor R6 is connected to the base of the first triode Q1, and the other end is connected to the output terminal of the comparator U2A. One end of the seventh resistor R7 is connected to the output terminal of the comparator U2A, and the other end is connected to the rated voltage signal terminal VCC1. The fifth resistor R5, the sixth resistor R6, and the seventh resistor R7 all play a current-limiting role to avoid damage to the first triode Q1.

[0054] In some embodiments, the relay drive control circuit further includes: an eighth resistor R8 and a ninth resistor R9. The base of the second triode Q2 is connected to the control terminal of the input control module through the eighth resistor R8, that is, one end of the eighth resistor R8 is connected to the base of the second triode Q2, and the other end is connected to the control terminal of the input control module; one end of the ninth resistor R9 is connected to the base of the second triode Q2, and the other end is connected to the collector of the second triode Q2. The eighth resistor R8 functions to limit the current and prevent the second triode Q2 from being damaged, and the ninth resistor R9 is used to keep the current of the collector of the second triode Q2 stable.

[0055] In some embodiments, the input control module includes: a microcontroller U1 (such as: a single-chip microcomputer) and an optocoupler U3. The anode of the light-emitting diode on the primary side of the optocoupler U3 is connected to the control voltage signal terminal VCC3, the cathode of the light-emitting diode is connected to the output terminal of the microcontroller U1, the emitter of the photosensitive triode on the secondary side of the optocoupler U3 is connected to the rated voltage signal terminal VCC1, the collector of the photosensitive triode is grounded, and the emitter of the photosensitive triode serves as the control terminal of the input control module. When the microcontroller U1 outputs a high level, the light-emitting diode is cut off, and the secondary side of the optocoupler U3 is not conducting. The input control module connects the rated voltage signal terminal VCC1 to the first input terminal of the comparator U2A and the base of the second triode Q2. When the microcontroller U1 outputs a low level, the light-emitting diode conducts, and the photosensitive triode on the secondary side of the optocoupler U3 conducts, grounding the rated voltage signal terminal VCC1, that is, connecting the ground terminal to the first input terminal of the comparator U2A and the base of the second triode Q2.

[0056] In some embodiments, the input control module further includes: a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12. Both the eleventh resistor R11 and the twelfth resistor R12 are pull-up resistors. The anode of the light-emitting diode is connected to the control voltage signal terminal VCC3 through the eleventh resistor R11, and the emitter of the photosensitive triode is connected to the rated voltage signal terminal VCC1 through the twelfth resistor R12. The control terminal of the input control module is connected to the first input terminal of the comparator U2A and the base of the second triode Q2 through the tenth resistor R10, and the tenth resistor R10 functions to limit the current.

[0057] As Figure 3 and Figure 4 shown, the working principle of the relay drive control circuit shown below is introduced as a whole. Figure 3 shown, the working principle of the relay drive control circuit shown below is introduced as a whole.

[0058] At time t1, the microcontroller U1 outputs a high level, the secondary side of the optocoupler U3 is not conducting, and the voltage at point A is high level (V A= Vcc1 × r9 / (r8 + r9 + r10 + r12), where r8, r9, r10, and r12 are the resistances of the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, and the twelfth resistor R12 respectively), the second triode Q2 conducts, and the second contact of the relay to be driven RLB is grounded; at the same time, the voltage at point B rises slowly, and within the time period from t1 to t2, the voltage at point B is less than the voltage at point C. The comparator U2A outputs a low level, the first triode Q1 conducts, and the first contact of the relay to be driven is connected to VCC1 through the first triode Q1, and the relay to be driven RLB is attracted. When the time exceeds t2, the comparator U2A outputs a high level, the first triode Q1 is turned off, and the relay to be driven RLB maintains the holding voltage through VCC2. At the moment of t3, when the microcontroller U1 outputs a low level and the secondary side of the optocoupler U3 conducts, the voltage at point A is grounded, that is, 0V, the second triode Q2 is cut off, and the relay to be driven RLB is disconnected.

[0059] Figure 3 In the relay drive control circuit, R1~R12 are all chip resistors. Through this circuit, the normal opening of the relay to be driven is realized, and there is no risk of burning out the relay. It avoids the EMC problem caused by using a PWM signal to equivalently represent a lower holding voltage, and there is no need to connect multiple electrolytic capacitors in parallel, so the circuit cost is relatively low.

[0060] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A relay drive control circuit, characterized in that: include: An input control module, a voltage division control module, a comparator, a first capacitor, a first transistor and a second transistor; The control end of the input control module is connected to the first input end of the comparator and the base of the second transistor, and is used to control the first input end of the comparator and the base of the second transistor to be connected to the rated voltage signal end or ground; The second input terminal of the comparator is connected to the rated voltage signal terminal through the voltage division control module, and the output terminal of the comparator is connected to the base of the first transistor; One end of the first capacitor is connected to the first input terminal of the comparator, and the other end is grounded; The emitter of the first transistor is connected to the rated voltage signal terminal, and the collector of the first transistor is connected to the first contact of the relay to be driven and the holding voltage signal terminal; The emitter of the second transistor is connected to the second contact of the relay to be driven, and the collector of the second transistor is grounded.

2. The relay drive control circuit according to claim 1, characterized in that: The voltage division control module includes: a first resistor, a second resistor and a second capacitor; One end of the first resistor is connected to the second input end of the comparator, and the other end is grounded; One end of the second resistor is connected to the second input end of the comparator, and the other end is connected to the rated voltage signal end; One end of the second capacitor is connected to the second input end of the comparator, and the other end is grounded.

3. The relay drive control circuit according to claim 1, characterized in that: Also includes: A voltage building control module, the voltage building control module comprises: a third resistor, the first input end of the comparator is connected to the control end of the input control module through the third resistor.

4. The relay drive control circuit according to claim 3, characterized in that: The voltage building control module further includes: a first diode and a fourth resistor having a resistance smaller than that of the third resistor; One end of the fourth resistor is connected to the first input end of the comparator, and the other end is connected to the anode of the first diode. The cathode of the first diode is connected to the control end of the input control module to form a series branch including the fourth resistor and the first diode, and the third resistor is connected in parallel with the series branch.

5. The relay drive control circuit according to claim 1, characterized in that: Also includes: A third capacitor, one end of the third capacitor is connected to the collector of the first transistor, and the other end is grounded.

6. The relay drive control circuit according to claim 1, characterized in that: Also includes: A second diode, wherein the anode of the second diode is connected to the emitter of the second transistor, and the cathode of the second diode is connected to the collector of the first transistor.

7. The relay drive control circuit according to claim 1, characterized in that: Also includes: A third diode, wherein the anode of the third diode is connected to the holding voltage signal terminal, and the cathode of the third diode is connected to the collector of the first transistor.

8. The relay drive control circuit according to claim 1, characterized in that: Also includes: a fifth resistor, a sixth resistor and a seventh resistor; The emitter of the first transistor is connected to the rated voltage signal terminal through a fifth resistor; The base of the first transistor is connected to the output end of the comparator through a sixth resistor; One end of the seventh resistor is connected to the output end of the comparator, and the other end is connected to the rated voltage signal end.

9. The relay drive control circuit according to claim 1, characterized in that: Also includes: an eighth resistor and a ninth resistor; The base of the second transistor is connected to the control end of the input control module through an eighth resistor; One end of the ninth resistor is connected to the base of the second transistor, and the other end is connected to the collector of the second transistor.

10. The relay drive control circuit according to any one of claims 1 to 9, characterized in that: The input control module includes: a microcontroller and a photocoupler, the anode of the light-emitting diode on the primary side of the photocoupler is connected to the control voltage signal terminal, the cathode of the light-emitting diode is connected to the output terminal of the microcontroller, the emitter of the phototransistor on the secondary side of the photocoupler is connected to the rated voltage signal terminal, the collector of the phototransistor is grounded, and the emitter of the phototransistor serves as the control terminal of the input control module.

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