Relay control circuit and relay control apparatus

Abstract

The utility model relates to a relay control circuit and a relay control device, and the relay control circuit comprises a relay module which comprises a first relay, a second relay and a circuit protection unit, and the circuit protection unit is connected between the second end of the first relay and the first end of the second relay; the switching module comprises a first switching unit and a second switching unit, the first switching unit is connected with the second end of the first relay and the first end of the second relay, and the second switching unit is connected with the first end of the first relay or the second end of the second relay; and the control module is connected with the first switching unit and the second switching unit and used for controlling opening and closing of the first switching unit and the second switching unit. The relay control circuit can effectively reduce the cost of a relay double-voltage driving scheme.

Description

TECHNICAL FIELD

[0001] The utility model relates to relay technology field especially relay control circuit and relay control equipment. BACKGROUND

[0002] In the relay double-voltage drive scheme, two voltage amplitudes, i.e., a working start voltage and a maintenance voltage, are usually required. Taking a 12V relay as an example, the corresponding working start voltage is 9V-13.2V. According to the relay specification, the maintenance voltage of the 12V relay is 6V, for example, for the double-voltage amplitude (12V, 6V) requirement, the traditional technology is to obtain the second voltage (6V) by increasing the DCDC (Direct Current to Direct Current) circuit, however, the increase of the DCDC circuit will increase the cost. Therefore, how to reduce the cost of the relay double-voltage drive scheme has become a technical problem to be solved at present. SUMMARY

[0003] Therefore, it is necessary to provide a relay control circuit and a relay control device capable of reducing the cost of the relay double-voltage drive scheme.

[0004] In a first aspect, the utility model provides a relay control circuit, comprising:

[0005] A relay module comprising a first relay, a second relay and a circuit protection unit, the circuit protection unit being connected between the second end of the first relay and the first end of the second relay;

[0006] A switching module comprising a first switching unit and a second switching unit, the first switching unit being connected to the second end of the first relay and the first end of the second relay respectively, and the second switching unit being connected to the first end of the first relay or the second end of the second relay;

[0007] A control module connected to the first switching unit and the second switching unit, for controlling the opening and closing of the first switching unit and the second switching unit.

[0008] In one of the embodiments, the protection direction of the circuit protection unit is from the first end of the second relay to the second end of the first relay.

[0009] In one of the embodiments, the first switching unit comprises a first switching subunit connected to the second end of the first relay and a second switching subunit connected to the first end of the second relay.

[0010] In the case that the first end is the lower end and the second end is the upper end, the first switching sub-unit is the lower pipe control unit, the second switching sub-unit is the upper pipe control unit, and the second switching unit is the upper pipe control unit connected with the first end of the first relay or the lower pipe control unit connected with the second end of the second relay.

[0011] In the case that the first end is the lower end and the second end is the upper end, the first switching sub-unit is the lower pipe control unit, the second switching sub-unit is the upper pipe control unit, and the second switching unit is the upper pipe control unit connected with the first end of the first relay or the lower pipe control unit connected with the second end of the second relay.

[0012] In one of the embodiments, the first switching unit comprises a first protection unit, and the second switching unit comprises a second protection unit.

[0013] In one of the embodiments, the relay control circuit further comprises a power supply module,

[0014] In the case that the second switching unit is connected with the second end of the second relay, the power supply module is connected with the first switching unit and the first end of the first relay;

[0015] In the case that the second switching unit is connected with the first end of the first relay, the power supply module is connected with the first switching unit and the second switching unit.

[0016] In one of the embodiments, the control module is further configured to control the first switching unit to be closed, so that the circuit protection unit is turned off, and the first starting voltage is provided for the first relay and the second starting voltage is provided for the second relay through the power supply module;

[0017] In one of the embodiments, the first starting voltage and the second starting voltage are the same.

[0018] In one of the embodiments, the control module is further configured to control the first switching unit to be opened, so that the circuit protection unit is turned on, the first relay and the second relay are connected in series, and the first maintaining voltage is provided for the first relay and the second maintaining voltage is provided for the second relay through the power supply module.

[0019] In one of the embodiments, the first maintaining voltage and the second maintaining voltage are the same.

[0020] In one of the embodiments, the circuit protection unit is a diode.

[0021] In the second aspect, the utility model provides a kind of relay control equipment, including the relay control circuit of any one in the first aspect.

[0022] The aforementioned relay control circuit and relay control device, since the first switching unit is connected to the second terminal of the first relay and the first terminal of the second relay respectively, and the second switching unit is connected to either the first terminal of the first relay or the second terminal of the second relay, and a circuit protection unit is connected between the second terminal of the first relay and the first terminal of the second relay, the control module controls the opening and closing of the first and second switching units. This allows the first switching unit to simultaneously control the current flow at the second terminal of the first relay and the first terminal of the second relay, while the second switching unit controls the current flow at either the first terminal of the first relay or the second terminal of the second relay, thereby controlling the conduction or cutoff of the circuit protection unit. This achieves the switching between the independent operating state and the series operating state of the first and second relays. When the first and second relays are in series operating state, the starting voltage can be evenly shared, thus achieving effective dual-voltage drive control of the relay's starting voltage and sustaining voltage using a general-purpose relay. This relay control circuit has a simple form, using a 12V general-purpose relay to achieve dual-voltage control without the need for an additional DC-DC circuit to obtain the sustaining voltage, effectively reducing the cost of the relay control circuit. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a relay control circuit as an example;

[0025] Figure 2 This is a relay control circuit according to another embodiment;

[0026] Figure 3 This is yet another embodiment of a relay control circuit;

[0027] Figure 4a for Figure 1 A schematic diagram of the principle structure of a relay control circuit;

[0028] Figure 4b for Figure 1 Another schematic diagram of the principle structure of the relay control circuit;

[0029] Figure 5 for Figure 4a and Figure 4b A specific embodiment of a relay control circuit;

[0030] Figure 6a For Figure 1 A schematic diagram of a principle structure of a relay control circuit;

[0031] Figure 6b For Figure 1 A schematic diagram of another principle structure of a relay control circuit;

[0032] Figure 7 For Figure 6a And Figure 6b A specific embodiment of a relay control circuit;

[0033] Figure 8 A schematic diagram of an application circuit of a relay control circuit for another embodiment.

[0034] Explanation of reference signs:

[0035] 100, relay module; 200, switching module; 300, control module; 400, power supply module; 101, first relay; 102, second relay; 103, circuit protection unit; 201, first switching unit; 202, second switching unit. DETAILED DESCRIPTION

[0036] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the specification of the present application herein is only for the purpose of describing specific embodiments and is not intended to limit the present application.

[0038] It can be understood that the terms "first", "second" and the like used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of the present application, the first resistor can be referred to as the second resistor, and similarly, the second resistor can be referred to as the first resistor. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0039] It can be understood that "connection" in the following embodiments, if the circuits, modules, units and the like connected to each other have the transmission of electrical signals or data, should be understood as "electrical connection", "communication connection" and the like.

[0040] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", or the like, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0041] In the conventional technology, the second voltage (6V) is obtained by adding a DCDC circuit, but adding the DCDC circuit increases the cost.

[0042] Therefore, in order to solve the cost pressure of the relay double-voltage driving scheme, a relay control circuit is proposed, which is applied to a charging pile.

[0043] Please refer to Figure 1 The relay control circuit of an embodiment includes a relay module 100, a switching module 200 and a control module 300. The relay module 100 includes a first relay 101, a second relay 102 and a circuit protection unit 103, and the circuit protection unit 103 is connected between the second end of the first relay 101 and the first end of the second relay 102. The switching module 200 includes a first switching unit 201 and a second switching unit 202, the first switching unit 201 is connected with the second end of the first relay 101 and the first end of the second relay 102 respectively, and the second switching unit 202 is connected with the first end of the first relay 101 or the second end of the second relay 102. The control module 300 is connected with the first switching unit 201 and the second switching unit 202, and is used for controlling the opening and closing of the first switching unit 201 and the second switching unit 202.

[0044] Optionally, the first relay 101 and the second relay 102 each include an electromagnetic system and a contact system, the electromagnetic system includes an electromagnetic coil, a fixed iron core and a movable armature. The first relay 101 and the second relay 102 each include two ends, an upper end and a lower end, which can also be referred to as an input end and an output end. For example, the first end and the second end can represent the upper end and the lower end of the electromagnetic coil respectively, or the lower end and the upper end of the electromagnetic coil respectively. The contact system includes at least one pair of contacts, and the contacts can be normally open contacts or normally closed contacts. When the electromagnetic coil is energized, the state of the contacts is changed by using the attraction force between the iron core and the armature, so that the first relay 101 and the second relay 102 realize the function of on / off circuit. For example, the first relay 101 and the second relay 102 can be single-pole double-throw type.

[0045] The second end of the first relay 101 is connected with the first end of the second relay 102, and the circuit protection unit 103 is connected between the second end of the first relay 101 and the first end of the second relay 102. The input end of the circuit protection unit 103 is connected with the second end of the first relay 101, and the output end of the circuit protection unit 103 is connected with the first end of the second relay 102.

[0046] Optionally, the protection direction of the circuit protection unit 103 is from the first end of the second relay 102 to the second end of the first relay 101, so as to allow the current to flow from the second end of the first relay 101 to the first end of the second relay 102, thereby preventing the reverse current from damaging the relay control circuit and each module in the circuit.

[0047] The first switching unit 201 is connected with the second end of the first relay 101 and the first end of the second relay 102 respectively, and is used for simultaneously controlling the flow-through state of the current of the second end of the first relay 101 and the first end of the second relay 102. The second switching unit 202 is connected with the first end of the first relay 101 or the second end of the second relay 102, and is used for controlling the flow-through state of the current of the first end of the first relay 101 or the second end of the second relay 102.

[0048] Optionally, the control module 300 can be an MCU. The control module 300 is used for controlling the opening and closing of the first switching unit 201 and the second switching unit 202, so as to realize the double-voltage effective driving control of the starting voltage and the maintaining voltage of the first relay 101 and the second relay 102.

[0049] Specifically, in the double-voltage driving process of the relay, the switching module 200 includes two states. State one is that the first switching unit 201 and the second switching unit 202 are both closed. State two is that the first switching unit 201 is disconnected on the basis of state one, and the second switching unit 202 still remains closed. When the control module 300 controls the first switching unit 201 and the second switching unit 202 to be closed, that is, the switching module 200 is in state one, at this time, the input end voltage of the circuit protection unit 103 is lower than the output end voltage, the circuit protection unit 103 is cut off, the current flows through the first relay 101 through the first relay 101 and the first switching unit 201, and flows through the second relay 102 through the first switching unit 201, the second relay 102 and the second switching unit 202, so that the first relay 101 and the second relay 102 both obtain the starting voltage. After the first relay 101 and the second relay 102 are stably attracted, the control module 300 disconnects the first switching unit 201 to enter state two.

[0050] When the switching module 200 is in state two, the input voltage of the circuit protection unit 103 is higher than the output voltage, the circuit protection unit 103 is turned on, and the current flows through the first relay 101, the second relay 102, and the second switching unit 202 to realize the flow through the first relay 101 and the second relay 102. At this time, the first relay 101 and the second relay 102 are in a series state, and the first relay 101 and the second relay 102 respectively obtain a maintaining voltage. The maintaining voltage is half of the starting voltage.

[0051] In the embodiment, since the first switching unit 201 is connected with the second end of the first relay 101 and the first end of the second relay 102 respectively, the second switching unit 202 is connected with the first end of the first relay 101 or the second end of the second relay 102, and the circuit protection unit 103 is connected between the second end of the first relay 101 and the first end of the second relay 102, by controlling the opening and closing of the first switching unit 201 and the second switching unit 202 through the control module 300, the first switching unit 201 controls the current flow state of the second end of the first relay 101 and the first end of the second relay 102 at the same time, the second switching unit 202 controls the current flow state of the first end of the first relay 101 or the second end of the second relay 102, thereby controlling the conduction or cut-off of the circuit protection unit 103, realizing the switching between the independent working state and the series working state of the first relay 101 and the second relay 102, when the first relay 101 and the second relay 102 are in the series working state, the starting voltage can be equally divided, and then the double-voltage effective driving control of the starting voltage and the maintaining voltage of the relay using the general relay is realized. The relay control circuit is simple in form, does not need to increase the DCDC circuit to obtain the maintaining voltage, and does not need to use the expensive general relay less than 50% of the maintaining voltage, greatly reducing the cost of the control circuit and solving the cost pressure of the relay double-voltage driving scheme. At the same time, the control circuit does not need to increase the LDO or the resistance voltage division to obtain the maintaining voltage, reduces the heat loss, and is more suitable for heat-sensitive applications such as charging piles. At the same time, the current flow state of the second end of the first relay 101 and the first end of the second relay 102 is controlled by using one switching unit, i.e., the first switching unit 201, which saves resources.

[0052] In an exemplary embodiment, the first switching unit 201 includes a first switching subunit connected with the second end of the first relay 101 and a second switching subunit connected with the first end of the second relay 102.

[0053] In the case that the first end is the lower end and the second end is the upper end, the first switching sub-unit is the lower pipe control unit, the second switching sub-unit is the upper pipe control unit, and the second switching unit 202 is the upper pipe control unit connected with the first end of the first relay 101 or the lower pipe control unit connected with the second end of the second relay 102.

[0054] In the case that the first end is the lower end and the second end is the upper end, the first switching sub-unit is the lower pipe control unit, the second switching sub-unit is the upper pipe control unit, and the second switching unit 202 is the upper pipe control unit connected with the first end of the first relay 101 or the lower pipe control unit connected with the second end of the second relay 102.

[0055] Optionally, in the case that the first end is the upper end and the second end is the lower end, the first switching sub-unit is the lower pipe control unit, the second switching sub-unit is the upper pipe control unit. When the second switching unit 202 is connected with the first end of the first relay 101, the second switching unit 202 is the upper pipe control unit. At this time, the switching module is in the form of two upper pipes and one lower pipe. When the second switching unit 202 is connected with the second end of the second relay 102, the second switching unit 202 is the lower pipe control unit. At this time, the switching module is in the form of two lower pipes and one upper pipe.

[0056] In the case that the first end is the lower end and the second end is the upper end, the first switching sub-unit is the lower pipe control unit, the second switching sub-unit is the upper pipe control unit, and the second switching unit 202 is the upper pipe control unit connected with the first end of the first relay 101 or the lower pipe control unit connected with the second end of the second relay 102.

[0057] Exemplarily, the upper pipe control unit can include at least one of an NPN triode, an NMOS tube and a Darlington tube, and the lower pipe control unit can include at least one of a PNP triode, a PMOS tube and a Darlington tube.

[0058] In the embodiment, the switching module can include two upper pipes, one lower pipe or two lower pipes and one upper pipe, which can stably realize the double-voltage driving of the relay.

[0059] In an exemplary embodiment, the first switching unit 201 includes a first protection unit, and the second switching unit 202 includes a second protection unit. Exemplarily, the first protection unit and the second protection unit can be a zener diode. The protection units included in the first switching unit 201 and the second switching unit 202 can protect the first switching unit 201 and the second switching unit 202, avoiding damage to the circuit.

[0060] Referring to Figure 2 For another embodiment of the relay control circuit, the relay control circuit further comprises a power supply module 400300, and the power supply module 400 is connected with the first switching unit 201 and the first end of the first relay 101 in the case that the second switching unit 202 is connected with the second end of the second relay 102.

[0061] Optionally, the power supply module 400 is connected with the first switching unit 201 and the first end of the first relay 101 respectively in the case that the second switching unit 202 is connected with the second end of the second relay 102, so that the first switching unit 201 and the second switching unit 202 can provide starting voltage for the first relay 101 and the second relay 102 respectively when they are closed, and at this time, the first relay 101 and the second relay 102 are in parallel.

[0062] When the first switching unit 201 is opened, the connection with the power supply module 400 is disconnected, so that the current does not pass through the first switching unit 201, and the current flows from the first end of the first relay 101, and then provides maintaining voltage for the first relay 101 and the second relay 102 in turn, at this time, the first relay 101 and the second relay 102 are in series, thereby realizing the double-voltage effective driving control of the starting voltage and the maintaining voltage of the relay.

[0063] Referring to Figure 3 For another embodiment of the relay control circuit, the relay control circuit further comprises a power supply module 400300, and the power supply module 400 is connected with the first switching unit 201 and the first end of the first relay 101 in the case that the second switching unit 202 is connected with the second end of the second relay 102.

[0064] Optionally, the power supply module 400 is connected with the first switching unit 201 and the first end of the first relay 101 respectively in the case that the second switching unit 202 is connected with the second end of the second relay 102, so that the first switching unit 201 and the second switching unit 202 can provide starting voltage for the first relay 101 and the second relay 102 respectively when they are closed, and at this time, the first relay 101 and the second relay 102 are in parallel.

[0065] When the first switching unit 201 is opened, the connection with the power supply module 400 is disconnected, so that the current does not pass through the first switching unit 201, and the current flows from the first end of the first relay 101, and then provides maintaining voltage for the first relay 101 and the second relay 102 in turn, at this time, the first relay 101 and the second relay 102 are in series, thereby realizing the double-voltage effective driving control of the starting voltage and the maintaining voltage of the relay.

[0066] Further, the control module 300 is further configured to control the first switching unit 201 and the second switching unit 202 to be closed, so that the circuit protection unit 103 is cut off, and the power supply module 400 provides the first starting voltage for the first relay 101 and the second starting voltage for the second relay 102; wherein the first starting voltage and the second starting voltage are the same.

[0067] When the control module 300 controls the first switching unit 201 and the second switching unit 202 to be closed, the input voltage of the circuit protection unit 103 is lower than the output voltage, the circuit protection unit 103 is cut off, the power supply module 400 provides the first starting voltage for the first relay 101, and the power supply module 400 provides the second starting voltage for the second relay 102.

[0068] In the embodiment, by controlling the first switching unit 201 and the second switching unit 202 to be closed, the first relay 101 and the second relay 102 are in the independent working state, and the power supply module 400 provides the starting voltage for the first relay 101 and the second relay 102 respectively.

[0069] Further, the control module 300 is further configured to control the first switching unit 201 to be closed, so that the circuit protection unit 103 is cut off, the first relay 101 and the second relay 102 are in series, and the power supply module 400 provides the first maintaining voltage for the first relay 101 and the second maintaining voltage for the second relay 102; wherein the first maintaining voltage and the second maintaining voltage are the same.

[0070] After the first relay 101 and the second relay 102 are stably attracted, the control module 300 controls the first switching unit 201 to be closed, the second switching unit 202 remains closed, the input voltage of the circuit protection unit 103 is higher than the output voltage, the circuit protection unit 103 is turned on, the first relay 101 and the second relay 102 are in series, the power supply module 400 provides the first maintaining voltage for the first relay 101 and the second maintaining voltage for the second relay 102.

[0071] For example, when the power supply voltage of the power supply module 400 is 12.3V, the first starting voltage and the second starting voltage are 12V, and the first maintaining voltage and the second maintaining voltage are 6V.

[0072] Optionally, the circuit protection unit 103 can be a diode, and it can be understood that the circuit protection unit 103 can also adopt other circuit protection devices, as long as it can realize the functions of turning on and cutting off the circuit.

[0073] In the embodiment, the first switching unit 201 is controlled to be open and the second switching unit 202 is controlled to be closed by the control module 300, so that the first relay 101 and the second relay 102 are switched from the independent working state to the series working state, and the power supply module 400 provides the maintaining voltage for the first relay 101 and the second relay 102 in series, thereby realizing the double-voltage effective driving control of the starting voltage and the maintaining voltage of the relay using the general-purpose relay, and further reducing the cost of the control circuit.

[0074] In an exemplary embodiment, the control module 300 further comprises: a first control port connected with the first switching unit 201 and used for controlling the opening and closing of the first switching unit 201; and a second control port connected with the second switching unit 202 and used for controlling the opening and closing of the second switching unit 202.

[0075] Optionally, the first control port and the second control port are both GPIO ports (General-purpose input / output) of an MCU. By using one port, i.e., the first control port, to control the opening and closing of the first switching unit 201, the opening and closing of the first switching sub-unit connected with the second end of the first relay 101 and the second switching sub-unit connected with the first end of the second relay 102 in the first switching unit 201 are simultaneously controlled, and the GPIO resources can be saved.

[0076] The first control port and the second control port are both in the form of a combination of a signal control power supply and a control switch, and can be equivalent to the GPIO port of the MCU. For example, the first control port and the second control port can be in the form of a combination of a 3.3V power supply and a switch.

[0077] When the control switches of the first control port and the second control port are both closed (corresponding to the GPIO of the MCU being given a high level), the first switching unit 201 and the second switching unit 202 are both closed, and the first relay 101 and the second relay 102 each obtain the starting voltage, thereby ensuring the stable closing of the relay. After the closing duration reaches a preset duration, the control switch of the first control port is opened (corresponding to the GPIO of the MCU being given a low level), and the control switch of the second control port remains closed (corresponding to the GPIO of the MCU being given a high level), so as to control the first switching unit 201 to be open and the second switching unit 202 to remain closed. At this time, the first relay 101 and the second relay 102 are in a series state and each obtain the maintaining voltage. The preset duration is more than 5 times of the relay pull-in time, for example, can be set to 100mS.

[0078] For example, when a 12V relay is used, the power supply voltage is selected as 12.3V, and when the control switches of the first control port and the second control port are both closed, the first relay 101 and the second relay 102 each obtain a starting voltage of 12V. When the control switch of the first control port is opened and the control switch of the second control port remains closed, the first relay 101 and the second relay 102 become in series, and each obtains a maintaining voltage of 6V.

[0079] In the embodiment, the opening and closing of the first switching sub-unit connected to the second end of the first relay 101 and the second switching sub-unit connected to the first end of the second relay 102 in the first switching unit 201 are simultaneously controlled by using one port, i.e., the first control port, thereby saving the GPIO resources of the MCU.

[0080] The design process of the above-mentioned relay control circuit is described below.

[0081] In order to realize the double-voltage driving of the relay, at least three switches are needed to be implemented. Taking the power supply voltage of 12.3V as an example, please refer to Figure 4a , which is in the form of two lower tubes and one upper tube. S1, S2 and S3 represent switches, K1 and K2 represent relays, S2 and S3 (S1 cooperates) are used to realize the starting voltage (12V), and S1 is used to realize the switching of the maintaining voltage (6V). When S1, S2 and S3 are all closed, the anode voltage of the diode is lower than the cathode voltage, the diode is cut off, the current flows through K1 and S2 to K1, and through S1, K2 and S3 to K2. Both relays obtain a starting voltage of 12V, and after the relays are stably attracted, S1 and S2 are opened.

[0082] Please refer to Figure 4b , when S1 and S2 are opened and S3 is closed, the anode voltage of the diode is higher than the cathode voltage, the diode is turned on, and the current flows through K1, K2 and S3 to K1 and K2. At this time, the two relays are in series, and each maintains a voltage of 6V.

[0083] Please refer to Figure 5 , which is in the form of Figure 4a and Figure 4bThe specific application circuit of the corresponding relay control circuit takes S1 and S2 as the first switching unit 201 which is closed and opened simultaneously. S3 is taken as the second switching unit 202. In order to save the GPIO resource of the MCU, the first switching unit 201 uses one GPIO port of the MCU for control, that is, the opening and closing of the first switching unit 201 is controlled through the first control port. The first control port includes SW1 and the 3.3V power supply connected with SW1, and the second control port includes SW2 and the 3.3V power supply connected with SW2, which are used for controlling the opening and closing of the second switching unit 202. K1 and K2 represent the first relay 101 and the second relay 102 respectively. The first switching unit 201 is connected with the second end of K1 and the first end of K2 respectively, and the second switching unit 202 is connected with the second end of K2. Diode D1 represents the circuit protection unit 103. Q1, Q2, Q3 and Q4 represent the switching tubes. R1, R2, R3, R4 and R5 represent the resistors.

[0084] Q1, Q2, Q3 and Q4 are used for controlling the on-off of K1 and K2. R1 and R2 are respectively used for limiting the current flowing through the base (or gate) of Q1 and Q2, so as to protect the GPIO of the MCU and the switching tube from being damaged due to the excessive input current. R3 and R4 in parallel constitute a voltage division module, which is used for dividing the voltage of 12.3V to provide a stable voltage to K2. R5 is respectively used for limiting the current flowing through the base (or gate) of Q4.

[0085] When SW1 and SW2 are closed together (corresponding to the GPIO of the MCU being given high level), the first switching unit 201 and the second switching unit 202 are closed, D1 is cut off, K1 and K2 respectively obtain the working starting voltage of 12V, and the stable closing of the relay is ensured.

[0086] When SW1 is opened (corresponding to the GPIO of the MCU being given low level), SW2 is maintained closed (corresponding to the GPIO of the MCU being given high level), the first switching unit 201 is opened, the second switching unit 202 is kept closed, D1 is turned on, at this time K1 and K2 become the series connection state, and each obtains the maintaining voltage of 6V.

[0087] Please refer to Figure 6a , which is in the form of two upper tubes and one lower tube. S4, S5 and S6 represent the switches, and K3 and K4 represent the relays. When the switches S4, S5 and S6 are all closed, the anode voltage of the diode is lower than the cathode voltage, the diode is cut off, the current flows through K3 through S5, K3 and S4, and flows through K4 through S6 and K4. Both of the relays obtain the starting voltage of 12V, and after the relays are stably attracted, S4 and S6 are opened.

[0088] Please refer to Figure 6bWhen S4 and S6 are open and S5 is closed, the anode voltage of the diode is higher than the cathode voltage, the diode conducts, and current flows through S5, K3, and K4. At this time, the two relays are in series and each maintains a voltage of 6V.

[0089] Please see Figure 7 ,for Figure 6a and Figure 6b The corresponding relay control circuit diagram shows that S4 and S6, which are simultaneously closed and open, are used as the first switching unit 201. S5 is used as the second switching unit 202. To save MCU GPIO resources, the first switching unit 201 is controlled by one MCU GPIO port, i.e., the opening and closing of the first switching unit 201 is controlled through the first control port. The first control port includes SW3 and a 3.3V power supply connected to SW3, and the second control port includes SW4 and a 3.3V power supply connected to SW4, used to control the opening and closing of the second switching unit 202. K3 and K4 represent the first relay 101 and the second relay 102, respectively. The first switching unit 201 is connected to the second terminal of K3 and the first terminal of K4, respectively, and the second switching unit 202 is connected to the first terminal of K3. Diode D2 represents the circuit protection unit 103. Q4, Q5, Q6, Q7, and Q8 represent switching transistors. R6, R7, R8, R9, R10, R11, and R12 represent resistors.

[0090] Q4, Q5, Q6, Q7, and Q8 are used to control the switching of K3 and K4. R6, R7, and R8 are used to limit the current flowing through the base (or gate) of Q4, Q7, and Q8, respectively, to prevent damage to the devices due to excessive input current. R9 and R10, connected in parallel, form a voltage divider module to divide the 12.3V voltage to provide a stable voltage to K3. R11 and R12, also connected in parallel, form a voltage divider module to provide a stable voltage to K4.

[0091] When SW3 and SW4 are closed together (corresponding to the GPIO of the MCU being given a high level), the first switching unit 201 and the second switching unit 202 are closed, D2 is cut off, and K3 and K4 each obtain a 12V working start voltage to ensure that the relay is stably closed.

[0092] When SW3 is disconnected (corresponding to the MCU's GPIO being given a low level) and SW4 remains closed (corresponding to the MCU's GPIO being given a high level), the first switching unit 201 is disconnected, the second switching unit 202 remains closed, and D2 is turned on. At this time, K3 and K4 become connected in series and each obtains a 6V sustaining voltage.

[0093] Please see Figure 8Fig. 6 is a schematic diagram of an application circuit of the relay control circuit in another embodiment, in the form of two upper tubes and one lower tube. In the figure, Z1 and Z2 represent the first protection unit in the first switching unit 201, Z3 represents the second protection unit in the second switching unit 202, Relay1 represents the first relay 101, and Relay2 represents the second relay 102. The first control port includes SW5 and a 3.3V power source connected to SW5, for controlling the opening and closing of the first switching unit 201. The second control port includes SW6 and a 3.3V power source connected to SW6, for controlling the opening and closing of the second switching unit 202.

[0094] In one exemplary embodiment, a relay control device is provided, comprising the relay control circuit in any of the above embodiments.

[0095] In the description of the present specification, the description of the terms "some embodiments", "other embodiments", "ideal embodiments", and the like means that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0096] The technical features of the above-described embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not contradict each other, they should be considered as within the scope of the present application.

[0097] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A relay control circuit, characterized by comprising: The relay module comprises a first relay, a second relay and a circuit protection unit, the circuit protection unit being connected between the second end of the first relay and the first end of the second relay. The switching module comprises a first switching unit and a second switching unit, the first switching unit being connected to the second end of the first relay and the first end of the second relay respectively, and the second switching unit being connected to the first end of the first relay or the second end of the second relay. The control module is connected to the first switching unit and the second switching unit, and is configured to control the opening and closing of the first switching unit and the second switching unit. The protection direction of the circuit protection unit is from the first end of the second relay to the second end of the first relay.

2. The relay control circuit according to claim 1, characterized by The first switching unit comprises a first switching subunit connected to the second end of the first relay and a second switching subunit connected to the first end of the second relay.

3. The relay control circuit of claim 1, wherein, In the case where the first end is the upper end and the second end is the lower end, the first switching subunit is a lower pipe control unit, the second switching subunit is an upper pipe control unit, and the second switching unit is an upper pipe control unit connected to the first end of the first relay or a lower pipe control unit connected to the second end of the second relay. In the case where the first end is the lower end and the second end is the upper end, the first switching subunit is an upper pipe control unit, the second switching subunit is a lower pipe control unit, and the second switching unit is a lower pipe control unit connected to the first end of the first relay or an upper pipe control unit connected to the second end of the second relay. The first switching unit comprises a first protection unit, and the second switching unit comprises a second protection unit.

4. The relay control circuit of claim 1, wherein, The relay control circuit further comprises a power supply module, 5. The relay control circuit of claim 1, wherein, In the case where the second switching unit is connected to the second end of the second relay, the power supply module is connected to the first switching unit and the first end of the first relay. In the case where the second switching unit is connected to the first end of the first relay, the power supply module is connected to the first switching unit and the second switching unit. The control module is further configured to control the first switching unit and the second switching unit to be closed, so that the circuit protection unit is cut off, the first relay is provided with a first starting voltage by the power supply module, and the second relay is provided with a second starting voltage by the power supply module.

6. The relay control circuit of claim 5, wherein, The first starting voltage and the second starting voltage are the same. The control module is further configured to control the first switching unit to be disconnected, so that the circuit protection unit is turned on, the first relay and the second relay are connected in series, the first relay is provided with a first maintaining voltage by the power supply module, and the second relay is provided with a second maintaining voltage by the power supply module.

7. The relay control circuit according to claim 6, characterized by The first maintaining voltage and the second maintaining voltage are the same. The circuit protection unit is a diode.

8. The relay control circuit of claim 1, wherein, The control module further comprises:

9. The relay control circuit of claim 1, wherein, a first control port connected to the first switching unit, configured to control the opening and closing of the first switching unit. ​ A second control port is connected with the second switching unit, for controlling the opening and closing of the second switching unit.

10. A relay control device characterized by comprising: A relay control circuit comprising any one of claims 1 to 9.

Images