Control circuit of relay and relay system

Abstract

The utility model provides a control circuit of a relay and a relay system. The control circuit of the relay comprises a switching power supply unit, a delay indication unit and a control unit, the input end of the switching power supply unit is used for being connected with a power supply, the output end of the switching power supply unit is electrically connected with the power end of the delay indication unit and the power end of the control unit and used for being electrically connected with the power end of the relay, and the output end of the delay indication unit is electrically connected with the first input end of the control unit. The output end of the control unit is electrically connected with the driving end of the relay; the delay indication unit is used for outputting a delay signal representing the delay requirement to the control unit. In the operation process, the delay time corresponding to the control unit can be changed by changing the delay signal output by the delay indication unit, and compared with the scheme of burning the delay time information in the control unit in advance, the flexibility is improved, and the use scenes with different delay requirements can be met.

Description

Technical Field

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

[0002] As an integral component of electrical control systems, time relays' delay functions play a crucial role in ensuring stable operation and precise control. The determination of the delay range not only impacts the system's response speed and accuracy, but also the safety and reliability of the entire system. Delay methods include electromagnetic, air-damped, and electronic delays. Electronic delays can be implemented using both hardware circuits and software control.

[0003] Existing software control to achieve delay usually burns the corresponding delay time information into the control unit in advance, so that the control unit performs delay control on the relay according to the burned delay time information during operation, resulting in poor flexibility. Utility Model Content

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

[0005] In a first aspect, in one embodiment, the present invention provides a control circuit for a relay, the control circuit for the relay comprising:

[0006] Switching power supply unit, delay indication unit and control unit;

[0007] The input end of the switching power supply unit is used to connect to the power supply, the output end of the switching power supply unit is electrically connected to the power end of the delay indication unit and the power end of the control unit respectively, and is used to be electrically connected to the power end of the relay, the output end of the delay indication unit is electrically connected to the first input end of the control unit, and the output end of the control unit is used to be electrically connected to the driving end of the relay;

[0008] The delay indicating unit is used to output a delay signal representing the delay time to the control unit, so that the control unit performs delay control according to the delay time corresponding to the delay signal.

[0009] In one embodiment, the switching power supply unit includes a rectifier and filter unit, a switching power supply chip, an energy storage inductor, an energy storage capacitor and a step-down unit;

[0010] The first input end of the rectifier and filter unit is used to be electrically connected to the live wire end of the power supply, the second input end of the rectifier and filter unit is used to be electrically connected to the neutral wire end of the power supply, the first output end of the rectifier and filter unit is electrically connected to the input end of the switching power supply chip, the output end of the switching power supply chip is electrically connected to the first end of the energy storage inductor, the second end of the energy storage inductor is electrically connected to the first end of the energy storage capacitor and the second output end of the rectifier and filter unit respectively, and the second end of the energy storage capacitor is grounded;

[0011] The first end of the energy storage capacitor is also electrically connected to the power supply end of the relay and the input end of the step-down unit to output the first power supply; the output end of the step-down unit is electrically connected to the power supply end of the delay indication unit and the power supply end of the control unit to output the second power supply.

[0012] In one embodiment, the rectifying and filtering unit includes a rectifying diode, a first filtering capacitor, a filtering inductor, and a second filtering capacitor;

[0013] The anode of the rectifier diode is used to be electrically connected to the live wire end of the power supply, the cathode of the rectifier diode is respectively electrically connected to the first end of the first filter capacitor and the first end of the filter inductor, the second end of the filter inductor is respectively electrically connected to the first end of the second filter capacitor and the input end of the switching power supply chip, and the second end of the first filter capacitor is respectively electrically connected to the neutral wire end of the power supply, the second end of the second filter capacitor and the second end of the energy storage inductor.

[0014] In one embodiment, the switching power supply unit further comprises a varistor and a fuse;

[0015] The first end of the varistor is electrically connected to the anode of the rectifier diode and the live wire end of the power supply, respectively; the second end of the varistor is electrically connected to the first end of the fuse and the neutral wire end of the power supply, respectively; the second end of the fuse is electrically connected to the second end of the energy storage inductor and the first end of the energy storage capacitor, respectively.

[0016] In one embodiment, the voltage-reducing unit includes a first current-limiting resistor, a first voltage-stabilizing diode, and a first charge-discharge capacitor;

[0017] The first end of the first current limiting resistor is electrically connected to the first end of the energy storage capacitor, the second end of the first current limiting resistor is electrically connected to the cathode of the first voltage stabilizing diode, the first end of the first charge and discharge capacitor, the power supply end of the delay indication unit and the power supply end of the control unit, respectively, and the anode of the first voltage stabilizing diode and the second end of the first charge and discharge capacitor are grounded respectively.

[0018] In one embodiment, the delay indicating unit includes a potentiometer;

[0019] The first fixed end of the potentiometer is electrically connected to the output end of the switching power supply unit, the second fixed end of the potentiometer is grounded, and the movable end of the potentiometer is electrically connected to the first input end of the control unit.

[0020] In one embodiment, the control circuit of the relay further includes a current detection unit;

[0021] The input end of the current detection unit is used to receive the current to be detected, the current to be detected includes the leakage current, and the output end of the current detection unit is electrically connected to the second input end of the control unit;

[0022] The current detection unit is used to output a detection signal indicating that the current is too large to the control unit when the current to be detected exceeds the current threshold.

[0023] In one embodiment, the current detection unit includes a second voltage-stabilizing diode, an optocoupler, a voltage-dropping resistor, a transistor, a rectifier bridge, a second current-limiting resistor, a third voltage-stabilizing diode, a second charge-discharge capacitor, a MOS transistor, and a bleeder resistor;

[0024] The cathode of the second voltage-stabilizing diode and the drain of the MOS transistor are respectively used to connect to the current to be detected, the anode of the second voltage-stabilizing diode is electrically connected to the anode of the light-emitting diode in the optocoupler, the cathode of the light-emitting diode in the optocoupler is electrically connected to the first end of the voltage drop resistor and the base of the transistor, respectively, the collector of the photosensitive transistor in the optocoupler is electrically connected to the output end of the switching power supply unit, and the emitter of the photosensitive transistor in the optocoupler is electrically connected to the second input end of the control unit;

[0025] The second end of the voltage-dropping resistor is electrically connected to the emitter of the transistor, the second end of the bleeder resistor, and the second output end of the rectifier bridge, respectively. The first input end of the rectifier bridge is used to be electrically connected to the live wire end of the power supply, and the second input end of the rectifier bridge is used to be electrically connected to the neutral wire end of the power supply. The first output end of the rectifier bridge is electrically connected to the first end of the second current-limiting resistor, and the second end of the second current-limiting resistor is electrically connected to the cathode of the third voltage-stabilizing diode, the first end of the second charge-discharge capacitor, and the gate of the MOS tube, respectively. The source of the MOS tube is electrically connected to the first end of the bleeder resistor.

[0026] In one embodiment, the control circuit of the relay further includes a channel switching unit;

[0027] The first input end of the channel switching unit is electrically connected to the output end of the control unit, the second input end of the channel switching unit is electrically connected to the output end of the switching power supply unit, and the output end of the channel switching unit is used to be electrically connected to the driving end of the relay.

[0028] In a second aspect, in one embodiment, the present invention provides a relay system, which includes a relay and a control circuit of the relay in any one of the above embodiments.

[0029] Through the control circuit and relay system of the above relay, a delay indication unit is added to output a delay signal representing the delay time to the control unit, so that the control unit can delay control the relay according to the delay time corresponding to the delay signal. During operation, the delay time corresponding to the control unit can be changed by changing the delay signal output by the delay indication unit. Compared with the solution of pre-burning the delay time information into the control unit, this improves flexibility and can meet the use scenarios of different delay times. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a schematic diagram of the structure of a control circuit of a relay in one embodiment of the present invention;

[0032] Figure 2 This is a structural diagram of a switching power supply unit in one embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of a specific circuit principle of a switching power supply unit in one embodiment of the present utility model;

[0034] Figure 4 This is a schematic diagram of a specific circuit principle of a step-down unit in one embodiment of the present utility model;

[0035] Figure 5 This is a schematic diagram of a specific circuit principle of a delay indication unit in one embodiment of the present utility model;

[0036] Figure 6 This is a schematic structural diagram of a control circuit of a relay including a current detection unit in one embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of a specific circuit principle of a current detection unit in one embodiment of the present utility model;

[0038] Figure 8 This is a schematic structural diagram of a control circuit of a relay including a channel switching unit in one embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the specific circuit principle of the channel switching unit in one embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, "multiple" means two or more, unless otherwise expressly specified. In the present application, the word "exemplary" is used to mean "serving as an example, illustration, or explanation." Any embodiment described in the present application as "exemplary" is not necessarily to be construed as being preferred or advantageous over other embodiments. The following description is provided to enable any person skilled in the art to implement and use the present invention. In the following description, details are listed for illustrative purposes. It should be understood that one of ordinary skill in the art will recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes are not described in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this application.

[0042] First, as Figure 1 As shown, in one embodiment, the utility model provides a control circuit of a relay, and the control circuit of the relay includes a switching power supply unit, a delay indication unit and a control unit.

[0043] The input end of the switching power supply unit is used to connect to the power supply, the output end of the switching power supply unit is electrically connected to the power end of the delay indication unit and the power end of the control unit respectively, and is used to be electrically connected to the power end of the relay, the output end of the delay indication unit is electrically connected to the first input end of the control unit, and the output end of the control unit is used to be electrically connected to the drive end of the relay.

[0044] A switching power supply unit (SPU) is a power supply that efficiently converts and controls electrical energy from input to output through high-speed switching of its internal power switching devices. It uses pulse-width modulation (PWM) technology to adjust the on-time and off-time ratio of the power switching devices to alter the output voltage. The power switching devices used in a SPU can be MOSFETs, for example.

[0045] The delay indicating unit is used to output a delay signal representing the delay time to the control unit.

[0046] The delay indication unit can output different delay signals, and different delay signals represent different delay times, so that the control unit can determine the corresponding delay time after receiving the delay signal sent by the delay indication unit.

[0047] The control unit may be a MCU (single chip microcomputer).

[0048] By adding a delay indicator unit to the control circuit of the relay, the delay signal representing the delay time is output to the control unit, so that the control unit can delay control the relay according to the delay time corresponding to the delay signal. During operation, the delay time corresponding to the control unit can be changed by changing the delay signal output by the delay indicator unit. Compared with the solution of pre-burning the delay time information into the control unit, the present invention has improved flexibility and can meet the use scenarios of different delay times.

[0049] like Figure 2 As shown, in one embodiment, the switching power supply unit includes a rectifier and filter unit, a switching power supply chip, an energy storage inductor, an energy storage capacitor and a step-down unit.

[0050] The first input end of the rectifier and filter unit is used to be electrically connected to the live wire end of the power supply, the second input end of the rectifier and filter unit is used to be electrically connected to the neutral wire end of the power supply, the first output end of the rectifier and filter unit is electrically connected to the input end of the switching power supply chip, the output end of the switching power supply chip is electrically connected to the first end of the energy storage inductor, the second end of the energy storage inductor is electrically connected to the first end of the energy storage capacitor and the second output end of the rectifier and filter unit respectively, and the second end of the energy storage capacitor is grounded.

[0051] In this embodiment, the switching power supply chip is connected in series between the rectifier and filter unit and the energy storage inductor. The switching power supply chip is used to control the on-off of the line between the rectifier and filter unit and the energy storage inductor. That is to say, the power switching device inside the switching power supply unit mentioned in the above embodiment is integrated in the switching power supply chip. The input end of the power switching device in the switching power supply chip is electrically connected to the first output end of the rectifier and filter unit, and the output end of the power switching device in the switching power supply chip is electrically connected to the first end of the energy storage inductor. The switching power supply chip controls the on-off of the power switching device integrated therein through pulse width modulation technology to achieve adjustment from input voltage to output voltage.

[0052] Among them, when the power switch device in the switching power supply chip is turned on, the live wire end of the power supply, the first input end of the rectifier and filter unit, the first output end of the rectifier and filter unit, the input end of the switching power supply chip, the output end of the switching power supply chip, the first end of the energy storage inductor, the second end of the energy storage inductor, the second output end of the rectifier and filter unit, the second input end of the rectifier and filter unit, and the neutral wire end of the power supply form an input loop, thereby charging the energy storage inductor and storing energy. When the power switch device in the switching power supply chip is turned off, the input loop formed above is disconnected, and the second end of the energy storage inductor, the first end of the energy storage capacitor, the second end of the energy storage capacitor, the ground end, the output end of the switching power supply chip, and the first end of the energy storage inductor form an output loop, thereby discharging the energy storage inductor, and then charging the energy storage capacitor, and finally supplying power to the subsequent stage through the voltage on the energy storage capacitor.

[0053] The first end of the energy storage capacitor is also electrically connected to the power supply end of the relay and the input end of the step-down unit respectively to output the first power supply VCC1.

[0054] In the relay control circuit, different units have different operating voltage requirements. For example, the relay's operating voltage has a relatively high amplitude, while the control unit and delay indicator unit have relatively low amplitudes. Therefore, the switching power supply unit needs to output power of different amplitudes.

[0055] In this embodiment, the voltage output by the energy storage capacitor is used as the first power supply VCC1. The first power supply VCC1 is used to output to the power supply end of the relay for power supply, and is used to output to the step-down unit for step-down processing.

[0056] The output end of the voltage reduction unit is electrically connected to the power supply end of the delay indication unit and the power supply end of the control unit respectively to output the second power supply.

[0057] The step-down unit can step down the input first power supply VCC1 to obtain a second power supply VCC2 with a reduced voltage amplitude. The second power supply VCC2 is used to output to the power supply end of the delay indication unit and the power supply end of the control unit for power supply.

[0058] In one embodiment, the first power supply VCC1 may be +12V, and the second power supply VCC2 may be +5V.

[0059] like Figure 3 As shown, in one embodiment, the rectification and filtering unit includes a rectification diode D1, a rectification diode D2, a first filtering capacitor CE2, a filtering inductor L3 and a second filtering capacitor CE3.

[0060] exist Figure 3 In the figure, the anode of the rectifier diode D1 is used to be electrically connected to the live wire terminal L1 of the power supply, the cathode of the rectifier diode D1 is electrically connected to the anode of the rectifier diode D2, the cathode of the rectifier diode D2 is electrically connected to the first end of the first filter capacitor CE2 and the first end of the filter inductor L3, respectively, the second end of the filter inductor L3 is electrically connected to the first end of the second filter capacitor CE3 and the input end SW of the switching power supply chip U2, the second end of the first filter capacitor CE2 is electrically connected to the neutral line terminal N of the power supply, the second end of the second filter capacitor CE3 and the second end of the energy storage inductor L2, and the output end ICG of the switching power supply chip U2 is electrically connected to the first end of the energy storage inductor L2.

[0061] In this embodiment, when the power switch in the switching power supply chip U2 is turned on, the live terminal L1 of the power supply, the rectifier diode D1, the rectifier diode D2, the filter inductor L3, the switching power supply chip U2, the energy storage inductor L2, and the neutral terminal N of the power supply form an input loop. When the power switch in the switching power supply chip U2 is turned off, the energy storage inductor L2, the energy storage capacitor CE1, the inductor L1, the dummy load resistor R5, the capacitor C2, the ground terminal, and the switching power supply chip U2 form an output loop.

[0062] like Figure 3 As shown, in one embodiment, the switching power supply unit further includes a varistor RV1 and a fuse R1.

[0063] Among them, the first end of the varistor RV1 is electrically connected to the anode of the rectifier diode D1 and the live wire terminal L1 of the power supply, respectively, the second end of the varistor RV1 is electrically connected to the first end of the fuse R1 and the neutral wire terminal N of the power supply, and the second end of the fuse R1 is electrically connected to the second end of the energy storage inductor L2 and the first end of the energy storage capacitor CE1.

[0064] Among them, the varistor RV1 is used for surge protection. When the power supply inputs a surge signal, the varistor RV1 can clamp the voltage across it to a relatively fixed voltage value, thereby protecting the subsequent circuit.

[0065] Among them, the fuse R1 is used for overcurrent protection. When the current in the circuit exceeds the threshold, the fuse R1 will be blown, thereby disconnecting the circuit.

[0066] Among them, Figure 3 In the embodiment, the first end of the energy storage capacitor CE1 outputs a first power supply of +12V.

[0067] Among them, Figure 3 In the embodiment, the feedback terminal VOUT of the switching power supply chip U2 is electrically connected to the second end of the energy storage inductor L2 and the second end of the fuse R1 respectively, for collecting the feedback voltage.

[0068] like Figure 4 As shown, in one embodiment, the voltage reduction unit includes a first current limiting resistor R4, a first voltage stabilizing diode ZD1 and a first charge-discharge capacitor C4.

[0069] Reference Figure 3 and Figure 4 , the first end of the first current limiting resistor R4 is electrically connected to the first end of the energy storage capacitor CE1 to access the first power supply (such as Figure 3 and Figure 4 The second end of the first current limiting resistor R4 is electrically connected to the cathode of the first voltage stabilizing diode ZD1, the first end of the first charge and discharge capacitor C4, the power supply end of the delay indicating unit and the power supply end of the control unit, respectively, to output the second power supply (such as Figure 4 The anode of the first voltage stabilizing diode ZD1 and the second end of the first charge-discharge capacitor C4 are grounded respectively.

[0070] Among them, the connected +12V first power supply charges the first charge and discharge capacitor C4 through the first current limiting resistor R4, thereby supplying power to the subsequent stage through the first charge and discharge capacitor C4. When the voltage on the first charge and discharge capacitor C4 exceeds the breakdown voltage of the first voltage-stabilizing diode ZD1, the first voltage-stabilizing diode ZD1 breaks down, and the connected +12V first power supply is introduced to the ground after passing through the first current-limiting resistor R4, and can no longer charge the first charge and discharge capacitor C4. When the voltage on the first charge and discharge capacitor C4 is continuously discharged to the subsequent stage and causes its voltage to be lower than the breakdown voltage of the first voltage-stabilizing diode ZD1, the first voltage-stabilizing diode ZD1 is restored and cut off, and the connected +12V first power supply charges the first charge and discharge capacitor C4 again through the first current limiting resistor R4. With the repeated breakdown and recovery of the first voltage-stabilizing diode ZD1, the voltage on the first charge and discharge capacitor C4 can be maintained at the target level, such as Figure 4The +5V in the circuit can provide stable power supply to the subsequent stage.

[0071] like Figure 5 As shown, in one embodiment, the delay indicating unit includes a potentiometer RP1.

[0072] The first fixed end of the potentiometer RP1 is electrically connected to the output end of the switching power supply unit to access the corresponding power supply (such as Figure 5 The second fixed end of the potentiometer RP1 is grounded, and the moving end of the potentiometer RP1 is electrically connected to the first input end of the control unit to output the corresponding delay signal tmset.

[0073] The moving end of potentiometer RP1 divides its resistance into two parts. Different divisions correspond to different values ​​of the output delay signal tmset. Therefore, in actual application, the operator can adjust the resistance of potentiometer RP1 to change the delay signal output to the control unit.

[0074] Among them, Figure 5 As shown, the delay indication unit further includes a capacitor C7 and a resistor R7, which form an RC filter circuit for filtering the signal output by the potentiometer RP1 so that the control unit can receive a more accurate delay signal tmset, thereby ensuring the accuracy of delay control.

[0075] like Figure 6 As shown, in one embodiment, the control circuit of the relay further includes a current detection unit.

[0076] The input end of the current detection unit is used to receive the current to be detected, which includes leakage current. The output end of the current detection unit is electrically connected to the second input end of the control unit.

[0077] The current detection unit is used to output a detection signal indicating that the current is too large to the control unit when the current to be detected exceeds the current threshold.

[0078] When the leakage current in the circuit is high, it can easily damage related components. For example, if a light-emitting diode is connected in series in the circuit, it can easily burn out the light-emitting diode. The leakage current is included in the current to be detected. When the leakage current is high, the corresponding current to be detected is also high. Therefore, a corresponding current threshold can be set. When the current to be detected exceeds the current threshold, it is determined that the leakage current in the current circuit is high, and a detection signal indicating excessive current is output to the control unit, so that the control unit can perform relevant protection control, such as disconnecting the corresponding circuit.

[0079] like Figure 7As shown, in one embodiment, the current detection unit includes a second voltage stabilizing diode ZD3, an optocoupler U3, a voltage drop resistor R18, a transistor Q3, a rectifier bridge BR1, a second current limiting resistor R16, a third voltage stabilizing diode ZD2, a second charge and discharge capacitor C11, a MOS tube Q2, and a bleeder resistor R10 and a bleeder resistor R11.

[0080] exist Figure 7 In the embodiment, the cathode of the second voltage stabilizing diode ZD3 and the drain of the MOS transistor Q2 are respectively used to connect to the current to be detected ATrip, the anode of the second voltage stabilizing diode ZD3 is electrically connected to the anode of the light emitting diode in the optocoupler U3, the cathode of the light emitting diode in the optocoupler U3 is electrically connected to the first end of the voltage drop resistor R18 and the base of the transistor Q3, and the collector of the photosensitive transistor in the optocoupler U3 is electrically connected to the output end of the switching power supply unit to connect to the corresponding power supply (such as Figure 7 The emitter of the phototransistor in the optocoupler U3 is electrically connected to the second input terminal of the control unit to output a detection signal Trip.

[0081] exist Figure 7 In the embodiment, the second end of the voltage-dropping resistor R18 is electrically connected to the emitter of the transistor Q3, the second end of the bleeder resistor R10, the second end of the bleeder resistor R11, and the second output end of the rectifier bridge BR1, respectively. The first input end of the rectifier bridge BR1 is used to be electrically connected to the live wire terminal L1 of the power supply, and the second input end of the rectifier bridge BR1 is used to be electrically connected to the neutral wire terminal N of the power supply. The first output end of the rectifier bridge BR1 is electrically connected to the first end of the second current-limiting resistor R16, and the second end of the second current-limiting resistor R16 is electrically connected to the cathode of the third voltage-stabilizing diode ZD2, the first end of the second charge-discharge capacitor C11, and the gate of the MOS transistor Q2, respectively. The source of the MOS transistor Q2 is electrically connected to the first end of the bleeder resistor R10 and the first end of the bleeder resistor R11, respectively.

[0082] When the power supply receives input from the live terminal L1 and the neutral terminal N, the rectifier bridge BR1 rectifies the input AC power into DC power, which is then processed into regulated DC power via resistors R13 and R12, a Zener diode ZD4, and capacitor CE4. The resulting regulated DC power charges the second charge-discharge capacitor C11 via the second current-limiting resistor R16, thereby outputting a high level to the gate of the MOS transistor Q2, thereby turning on the MOS transistor Q2. When the voltage across the second charge-discharge capacitor C11 exceeds the breakdown voltage of the third Zener diode ZD2, the third Zener diode ZD2 breaks down and turns on. The regulated DC power generated by the previous stage can no longer charge the second charge-discharge capacitor C11, and the energy in the second charge-discharge capacitor C11 is discharged through the third Zener diode ZD2. When the voltage on the second charge-discharge capacitor C11 drops below the breakdown voltage of the third zener diode ZD2 due to discharge, the third zener diode ZD2 turns off, allowing the regulated DC power obtained by the previous stage to continue charging the second charge-discharge capacitor C11. The breakdown conduction and recovery of the third zener diode ZD2 allow the gate of the MOS transistor to be connected to a stable high level.

[0083] When the current A Trip to be detected does not exceed the current threshold, the current A Trip to be detected passes through the MOS transistor Q2, the bleeder resistor R10, the bleeder resistor R11, and the rectifier bridge BR1, and then returns to the live terminal L1 or the neutral terminal N of the power supply, forming a loop to ensure that related devices that operate based on the current A Trip to be detected can operate normally. When the current A Trip to be detected exceeds the current threshold, the second voltage stabilizing diode ZD3 breaks down and turns on. The current A Trip to be detected passes through the second voltage stabilizing diode ZD3, the resistor R14, the resistor R15, the light-emitting diode in the optocoupler U3, and the voltage drop resistor R18, and then returns to the live terminal L1 or the neutral terminal N of the power supply, forming a loop, turning on the transistor Q3 and the phototransistor in the optocoupler U3. The energy on capacitor CE4 is discharged through resistor R19 and transistor Q3. The energy on the second charge-discharge capacitor C11 is discharged through the second current-limiting resistor R16 and transistor Q3. The gate voltage of MOS transistor Q2 is pulled down, turning off MOS transistor Q2, thereby protecting low-power components such as bleeder resistors R10 and R11. At the same time, the connected +5V second power supply is output through the phototransistor of optocoupler U3 to output a high-level detection signal Trip to the control unit.

[0084] Among them, Figure 7 In the embodiment, the current detection unit further includes a pull-down resistor R17, a capacitor C12 and a capacitor C13, which are used together to provide a detection signal Trip with a stable voltage.

[0085] Among them, Figure 7In the embodiment, the current detection unit further includes a varistor RV2 and a TVS tube D7. The varistor RV2 is used for surge protection, and the specific reference may be made to the varistor RV1 in the above embodiment (e.g. Figure 3 TVS diode D7 is used for voltage clamping.

[0086] Among them, Figure 7 In the circuit, the current detection unit also includes a diode D6 and a capacitor C10. Diode D6 is used to prevent the gate of MOS transistor Q2 from floating. Capacitor C10 can adjust the charge and discharge speed of MOS transistor Q2, thereby changing its conduction and cutoff characteristics, which can improve the circuit's response speed to a certain extent.

[0087] like Figure 8 As shown, in one embodiment, the control circuit of the relay further includes a channel switching unit.

[0088] The first input end of the channel switching unit is electrically connected to the output end of the control unit, the second input end of the channel switching unit is electrically connected to the output end of the switching power supply unit, and the output end of the channel switching unit is used to be electrically connected to the driving end of the relay.

[0089] When the channel switching unit connects the first input and output terminals, the circuit between the output terminal of the control unit and the driver terminal of the relay is connected. At this time, the control unit can control the driver terminal of the relay to achieve delay control. When the channel switching unit connects the second input and output terminals, the circuit between the output terminal of the switching power supply unit and the driver terminal of the relay is connected. At this time, the driver terminal of the relay is continuously connected to the corresponding power supply, and the control unit cannot control the driver terminal of the relay, thereby achieving instantaneous power-on.

[0090] Through the channel switching unit, different driving modes of the relay can be realized to adapt to different scenarios.

[0091] like Figure 9 As shown, in one embodiment, the channel switching unit includes a dip switch SW1, pin 1 of the dip switch SW1 is electrically connected to the output end of the control unit to receive the corresponding control signal OUT, and pin 3 of the dip switch SW1 is electrically connected to the output end of the switching power supply unit to receive the corresponding power supply (such as Figure 9 The +5V second power supply in the relay), the pin 2 of the dip switch SW1 is electrically connected to the base of the transistor Q1 through the current limiting resistor R8, and the +12V first power supply and the Vz end (i.e., both ends of the freewheeling diode D5) are connected in parallel with the relay line.

[0092] Among them, when the dip switch SW1 is in the first gear, the connected control signal OUT is converted to a high level after a certain delay and output to the base of the transistor Q1. The transistor Q1 is turned on with a delay, and the +12V first power supply passes through the relay coil and the transistor Q1 and then reaches the ground, forming a loop. The relay coil is energized and the relay is attracted to realize delay control.

[0093] Among them, when the dip switch SW1 is in the second gear, the connected +5V second power supply is immediately output to the base of the transistor Q1, and the transistor Q1 is immediately turned on. The +12V first power supply passes through the relay coil and the transistor Q1 and then reaches the ground, forming a loop. The relay coil is energized and the relay is attracted to achieve instantaneous control.

[0094] Among them, when the transistor Q1 is turned off, the energy on the relay coil is discharged through the freewheeling diode D5 until it is insufficient to maintain the attraction, the relay coil is powered off, and the relay is disconnected.

[0095] Among them, Figure 9 In the embodiment, capacitor C8 is used to filter the connected +12V first power supply.

[0096] Among them, Figure 9 In the circuit, resistor R9 serves as a base pull-down resistor of transistor Q1 to keep the base voltage of transistor Q1 stable.

[0097] Among them, Figure 9 In the circuit, capacitor C9 is used as a filter capacitor to prevent high-frequency signals from causing transistor Q1 to be mis-conducted and causing the relay to malfunction.

[0098] In a second aspect, in one embodiment, the present invention provides a relay system, which includes a relay and a control circuit of the relay in any one of the above embodiments.

[0099] The above relay system is equipped with a delay indicator unit to output a delay signal representing the delay time to the control unit, so that the control unit can delay control the relay according to the delay time corresponding to the delay signal. During operation, the delay time corresponding to the control unit can be changed by changing the delay signal output by the delay indicator unit. Compared with the solution of pre-burning the delay time information into the control unit, this improves flexibility and can meet the use scenarios of different delay times.

[0100] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above and will not be repeated here.

[0101] The control circuit and relay system of a relay provided by the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there may be changes in the specific implementation methods and application scope. In summary, the contents of this specification should not be understood as limiting the present invention.

[0102] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A control circuit of a relay, characterized in that: The control circuit of the relay comprises: Switching power supply unit, delay indication unit and control unit; The input end of the switching power supply unit is used to connect to the power supply, the output end of the switching power supply unit is electrically connected to the power supply end of the delay indication unit and the power supply end of the control unit respectively, and is used to be electrically connected to the power supply end of the relay, the output end of the delay indication unit is electrically connected to the first input end of the control unit, and the output end of the control unit is used to be electrically connected to the driving end of the relay; The delay indicating unit is used to output a delay signal representing the delay time to the control unit, so that the control unit performs delay control according to the delay time corresponding to the delay signal.

2. The control circuit of the relay according to claim 1, characterized in that: The switching power supply unit includes a rectifier and filter unit, a switching power supply chip, an energy storage inductor, an energy storage capacitor and a step-down unit; The first input end of the rectifier and filter unit is used to be electrically connected to the live wire end of the power supply, the second input end of the rectifier and filter unit is used to be electrically connected to the neutral wire end of the power supply, the first output end of the rectifier and filter unit is electrically connected to the input end of the switching power supply chip, the output end of the switching power supply chip is electrically connected to the first end of the energy storage inductor, the second end of the energy storage inductor is electrically connected to the first end of the energy storage capacitor and the second output end of the rectifier and filter unit respectively, and the second end of the energy storage capacitor is grounded; The first end of the energy storage capacitor is also electrically connected to the power supply end of the relay and the input end of the step-down unit to output a first power supply; the output end of the step-down unit is electrically connected to the power supply end of the delay indication unit and the power supply end of the control unit to output a second power supply.

3. The control circuit of the relay according to claim 2, characterized in that: The rectification and filtering unit includes a rectification diode, a first filtering capacitor, a filtering inductor and a second filtering capacitor; The anode of the rectifier diode is used to be electrically connected to the live wire end of the power supply, the cathode of the rectifier diode is respectively electrically connected to the first end of the first filter capacitor and the first end of the filter inductor, the second end of the filter inductor is respectively electrically connected to the first end of the second filter capacitor and the input end of the switching power supply chip, and the second end of the first filter capacitor is respectively electrically connected to the neutral wire end of the power supply, the second end of the second filter capacitor and the second end of the energy storage inductor.

4. The control circuit of the relay according to claim 3, characterized in that: The switching power supply unit also includes a varistor and a fuse; The first end of the varistor is electrically connected to the anode of the rectifier diode and the live wire end of the power supply, respectively; the second end of the varistor is electrically connected to the first end of the fuse and the neutral wire end of the power supply, respectively; the second end of the fuse is electrically connected to the second end of the energy storage inductor and the first end of the energy storage capacitor, respectively.

5. The control circuit of the relay according to claim 2, characterized in that: The voltage-reducing unit includes a first current-limiting resistor, a first voltage-stabilizing diode, and a first charge-discharge capacitor; The first end of the first current limiting resistor is electrically connected to the first end of the energy storage capacitor, the second end of the first current limiting resistor is electrically connected to the cathode of the first voltage stabilizing diode, the first end of the first charge and discharge capacitor, the power supply end of the delay indication unit and the power supply end of the control unit, respectively, and the anode of the first voltage stabilizing diode and the second end of the first charge and discharge capacitor are grounded respectively.

6. The control circuit of the relay according to any one of claims 1 to 5, characterized in that: The delay indicating unit includes a potentiometer; The first fixed end of the potentiometer is electrically connected to the output end of the switching power supply unit, the second fixed end of the potentiometer is grounded, and the movable end of the potentiometer is electrically connected to the first input end of the control unit.

7. The control circuit of the relay according to any one of claims 1 to 5, characterized in that: The control circuit of the relay further includes a current detection unit; The input end of the current detection unit is used to receive the current to be detected, and the current to be detected includes a leakage current. The output end of the current detection unit is electrically connected to the second input end of the control unit; The current detection unit is used to output a detection signal indicating that the current is too large to the control unit when the current to be detected exceeds a current threshold.

8. The control circuit of the relay according to claim 7, characterized in that: The current detection unit includes a second voltage-stabilizing diode, an optocoupler, a voltage-dropping resistor, a transistor, a rectifier bridge, a second current-limiting resistor, a third voltage-stabilizing diode, a second charge-discharge capacitor, a MOS tube and a discharge resistor; The cathode of the second voltage-stabilizing diode and the drain of the MOS transistor are respectively used to connect to the current to be detected, the anode of the second voltage-stabilizing diode is electrically connected to the anode of the light-emitting diode in the optocoupler, the cathode of the light-emitting diode in the optocoupler is electrically connected to the first end of the voltage-drop resistor and the base of the transistor, the collector of the phototransistor in the optocoupler is electrically connected to the output end of the switching power supply unit, and the emitter of the phototransistor in the optocoupler is electrically connected to the second input end of the control unit; The second end of the voltage-dropping resistor is electrically connected to the emitter of the transistor, the second end of the bleeder resistor, and the second output end of the rectifier bridge, respectively. The first input end of the rectifier bridge is used to be electrically connected to the live wire end of the power supply, and the second input end of the rectifier bridge is used to be electrically connected to the neutral wire end of the power supply. The first output end of the rectifier bridge is electrically connected to the first end of the second current-limiting resistor, and the second end of the second current-limiting resistor is electrically connected to the cathode of the third voltage-stabilizing diode, the first end of the second charge-discharge capacitor, and the gate of the MOS transistor, respectively. The source of the MOS transistor is electrically connected to the first end of the bleeder resistor.

9. The control circuit of the relay according to any one of claims 1 to 5, characterized in that: The control circuit of the relay further includes a channel switching unit; The first input end of the channel switching unit is electrically connected to the output end of the control unit, the second input end of the channel switching unit is electrically connected to the output end of the switching power supply unit, and the output end of the channel switching unit is used to be electrically connected to the driving end of the relay.

10. A relay system, characterized in that: The relay system includes a relay and a control circuit of the relay according to any one of claims 1 to 9.

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