A relay drive circuit and control method

Abstract

The disclosure provides a relay driving circuit and a control method, and relates to the technical field of power electronics.The circuit comprises a relay, a main driving switch tube, an auxiliary turn-off circuit, a control unit and a power supply circuit.The auxiliary turn-off circuit comprises a first auxiliary switch tube and a second auxiliary switch tube.The current input end of the main driving switch tube is connected to the relay, the control end is connected to the control unit, and the current output end is grounded.The current output end and the current input end of the first auxiliary switch tube are connected in parallel across the relay, the control end is connected to the current input end of the second auxiliary switch tube and the power supply circuit, the current output end of the second auxiliary switch tube is grounded, and the control end is connected to the control unit.The control unit acquires a power supply voltage value, and outputs a turn-off signal to the main driving switch tube and the second auxiliary switch tube if a first preset condition is not met.When the main driving switch tube cannot be turned off due to short circuit, the first auxiliary switch tube short-circuits the relay, so that the relay stops working, and the reliability of the circuit is improved.

Description

Technical Field

[0001] This disclosure relates to the field of power electronics technology, and in particular to a relay drive circuit and control method. Background Technology

[0002] In the field of power electronics technology, the use of a single switching transistor to drive a relay may result in the switching transistor being short-circuited, causing the relay coil to remain energized and the contacts to fail to disconnect, thus creating a safety hazard for the entire circuit.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This disclosure provides a relay driving circuit and control method, which at least to some extent overcomes the situation in related technologies where the switching transistor is short-circuited due to breakdown, causing the relay coil to be continuously energized, resulting in safety hazards in the overall circuit, and improves the reliability of relay operation and the overall circuit.

[0005] Other features and advantages of this disclosure will become apparent from the following detailed description, or may be learned in part from practice of this disclosure.

[0006] In a first aspect, embodiments of this disclosure provide a relay driving circuit, including: a relay, a main driving switch, an auxiliary shutdown circuit, a control unit, and a power supply circuit; the auxiliary shutdown circuit includes: a first auxiliary switch and a second auxiliary switch; The current input terminal of the main drive switch is connected to a relay, and then connected to the power supply circuit via the relay. The control terminal of the main drive switch is connected to the control unit, and the current output terminal of the main drive switch is grounded. The current output terminal and current input terminal of the first auxiliary switch are connected in parallel to the two ends of the relay. The control terminal of the first auxiliary switch is connected to the current input terminal of the second auxiliary switch and the power supply circuit. The current output terminal of the second auxiliary switch is grounded. The control terminal of the second auxiliary switch is connected to the control unit. The control unit is used to obtain the power supply voltage value of the power supply circuit. If the power supply voltage value does not meet the first preset condition, it outputs a turn-off signal to the main drive switch and the second auxiliary switch to stop the relay from working.

[0007] The embodiments of this disclosure provide a relay driving circuit and control method, relating to the field of power electronics technology, including: a relay, a main driving switch, an auxiliary shutdown circuit, a control unit, and a power supply circuit; the auxiliary shutdown circuit includes: a first auxiliary switch and a second auxiliary switch, the current input terminal of the main driving switch is connected to the relay, the control terminal of the main driving switch is connected to the control unit, and the current output terminal of the main driving switch is grounded; the current output terminal and the current input terminal of the first auxiliary switch are connected in parallel across the two ends of the relay, the control terminal of the first auxiliary switch is connected to the current input terminal of the second auxiliary switch and the power supply circuit, the current output terminal of the second auxiliary switch is grounded, and the control terminal of the second auxiliary switch is connected to the control unit; the control unit is used to obtain the power supply voltage value of the power supply circuit, and if the power supply voltage value does not meet a first preset condition, it outputs a shutdown signal to the main driving switch and the second auxiliary switch to stop the relay from working. When the main drive switch fails to turn off due to a short circuit, the second auxiliary switch is turned off, thereby turning on the first auxiliary switch. The first auxiliary switch can then short-circuit the relay, causing it to stop working. This circuit structure, by employing a multi-transistor redundant turn-off method, breaks through the problem of turn-off failure caused by transistor breakdown. When one transistor fails, the other transistor takes on the 100% turn-off function. Even in the event of a single transistor failure, the circuit can still enter a safe state, thereby improving its safety and reliability.

[0008] In one possible embodiment, it further includes: a diagnostic sampling circuit; One end of the diagnostic sampling circuit is connected to the current input terminals of the relay and the main drive switch transistor, respectively; the other end of the diagnostic sampling circuit is connected to the control unit. The control unit is also used to acquire the voltage value of the diagnostic sampling point at the initial power-on moment. If the voltage value of the diagnostic sampling point does not meet the second preset condition, an alarm signal is issued.

[0009] To address the lack of diagnostic mechanisms in related technologies, specifically the problem of sudden loss of control where a broken drive transistor cannot be detected, resulting in system operation with a fault, the aforementioned circuit structure advances the diagnostic opportunity to power-on pre-checking of the circuit structure's sampling points before system startup, achieving zero-risk startup with a fault.

[0010] In one possible embodiment, the second preset condition is not met when the voltage value of the diagnostic sampling point is less than 0.5V.

[0011] In one possible embodiment, it further includes: The control unit is also used to output a turn-on signal to the main drive switch and the second auxiliary switch at the initial power-on moment if the voltage value of the diagnostic sampling point meets the third preset condition, so that the relay starts to work.

[0012] In one possible embodiment, the third preset condition is that the voltage value of the diagnostic sampling point is greater than a preset multiple of the power supply voltage value.

[0013] In one possible embodiment, the power supply circuit includes a DC voltage source and a constant current drive circuit.

[0014] In one possible embodiment, the constant current driving circuit includes: a first constant current driving switch, a second constant current driving switch, a first resistor, a second resistor, and a first diode; The cathode of the first diode is connected between one end of the relay and the current input terminal of the main drive switch, and the anode of the first diode is connected to the other end of the relay, the current output terminal of the first constant current drive switch, and one end of the first resistor. The other end of the first resistor is connected to the control terminal of the first constant current drive switch and the current output terminal of the second constant current drive switch, respectively. The current input terminal of the first constant current drive switch is connected to one end of the second resistor and the control terminal of the second constant current drive switch, respectively. The other end of the second resistor and the current input terminal of the second constant current drive switch are connected to the DC voltage source of the power supply circuit.

[0015] To address the issue of unstable relay operation characteristics under voltage fluctuations in related technologies, where the relay's operation and release characteristics change accordingly when the input voltage fluctuates, resulting in random relay operation and low reliability, a constant current drive circuit is used to ensure that the relay's input voltage remains stable.

[0016] In one possible embodiment, the maximum current of the constant current drive circuit is configured according to the first resistor.

[0017] In one possible embodiment, the auxiliary shutdown circuit further includes: a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a first diode; The third resistor is connected between the power supply circuit and the control terminal of the first auxiliary switch, and between the power supply circuit and the current input terminal of the second auxiliary switch. The fourth resistor is connected between the control terminal and the current output terminal of the first auxiliary switch. The cathode of the first diode is connected to the current output terminal of the first auxiliary switch and the fourth resistor, and the anode of the first diode is connected between the relay and the current input terminal of the main drive switch. The fifth resistor is connected between the control terminal and the current output terminal of the second auxiliary switch, and the sixth resistor is connected between the control terminal and the control unit of the second auxiliary switch.

[0018] In one possible embodiment, it further includes: a seventh resistor and an eighth resistor; the control terminal of the main drive switch is grounded via the eighth resistor; The seventh resistor is connected between the control terminal of the main drive switch and the control unit.

[0019] In a second aspect, embodiments of this disclosure provide a control method for a relay drive circuit, used in the relay drive circuit as described in the first aspect, the method comprising: Obtain the power supply voltage value of the power supply circuit; If the power supply voltage does not meet the first preset condition, a turn-off signal is output to the main drive switch and the second auxiliary switch to stop the relay from working.

[0020] In one possible embodiment, the method further includes: At the initial power-on moment, acquire the voltage value of the diagnostic sampling point; If the voltage value at the diagnostic sampling point does not meet the second preset condition, an alarm signal will be issued.

[0021] In one possible embodiment, the method further includes: At the initial power-on moment, if the voltage value of the diagnostic sampling point meets the third preset condition, a conduction signal is output to the main drive switch and the second auxiliary switch to enable the relay to start working.

[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0024] Figure 1 This illustration shows one of the structural schematic diagrams of a relay drive circuit according to an embodiment of the present disclosure; Figure 2 This is a second schematic diagram of the structure of a relay drive circuit according to an embodiment of the present disclosure; Figure 3 This is shown as a third schematic diagram of the structure of a relay drive circuit according to an embodiment of the present disclosure; Figure 4 This is shown as a fourth schematic diagram of the structure of a relay drive circuit according to an embodiment of the present disclosure; Figure 5 A flowchart illustrating a control method for a relay drive circuit according to an embodiment of this disclosure is shown. Detailed Implementation

[0025] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0026] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0027] In the field of power electronics technology, the use of a single switching transistor to drive a relay may result in the switching transistor being short-circuited, causing the relay coil to remain energized and the contacts to fail to disconnect, thus creating a safety hazard for the entire circuit.

[0028] Based on this, a relay drive circuit with redundant turn-off capability is designed to address the insufficient reliability of relay operation and the overall circuit. As shown below, this disclosure provides a relay drive circuit and control method, relating to the field of power electronics technology, including: a relay, a main drive switch, an auxiliary turn-off circuit, a control unit, and a power supply circuit; the auxiliary turn-off circuit includes: a first auxiliary switch and a second auxiliary switch; the current input terminal of the main drive switch is connected to the relay, the control terminal of the main drive switch is connected to the control unit, and the current output terminal of the main drive switch is grounded; the current output terminal and current input terminal of the first auxiliary switch are connected in parallel across the two ends of the relay; the control terminal of the first auxiliary switch is connected to the current input terminal of the second auxiliary switch and the power supply circuit; the current output terminal of the second auxiliary switch is grounded, and the control terminal of the second auxiliary switch is connected to the control unit; the control unit is used to obtain the power supply voltage value of the power supply circuit; if the power supply voltage value does not meet a first preset condition, it outputs a turn-off signal to the main drive switch and the second auxiliary switch to stop the relay from working. When the main drive switch fails to turn off due to a short circuit, the second auxiliary switch is turned off, thereby turning on the first auxiliary switch. The first auxiliary switch can then short-circuit the relay, causing it to stop working. This achieves multiple shutdowns of the relay, improving the reliability of the relay operation and the overall circuit.

[0029] The following detailed description of this exemplary implementation method is provided in conjunction with the accompanying drawings and embodiments.

[0030] first, Figure 1 This diagram illustrates one of the structural schematics of a relay drive circuit according to an embodiment of the present disclosure, such as... Figure 1 As shown, the relay drive circuit 100 includes: a relay JK1, a main drive switch Q1, an auxiliary shutdown circuit 110, a control unit 120, and a power supply circuit 130. The auxiliary shutdown circuit 110 includes: a first auxiliary switch Q2 and a second auxiliary switch Q3.

[0031] The current input terminal of the main drive switch Q1 is connected to relay JK1, and then connected to the power supply circuit 130 via relay JK1. The control terminal of the main drive switch Q1 is connected to the control unit 120, and the current output terminal of the main drive switch Q1 is grounded. The control unit 120 is also directly connected to the power supply circuit 130 for sampling the power supply voltage value of the power supply circuit.

[0032] The current output terminal and current input terminal of the first auxiliary switch Q2 are connected in parallel to the two ends of the relay JK1. The control terminal of the first auxiliary switch Q2 is connected to the current input terminal of the second auxiliary switch Q3 and the power supply circuit 130. The current output terminal of the second auxiliary switch Q3 is grounded. The control terminal of the second auxiliary switch Q3 is connected to the control unit 120.

[0033] The AC input terminal of the first auxiliary switch Q2 is connected between the power supply circuit 130 and the relay JK1, and the AC output terminal of the first auxiliary switch Q2 is connected between the relay JK1 and the main drive switch Q1.

[0034] The control unit 120 obtains the power supply voltage value of the power supply circuit 130. If the power supply voltage value does not meet the first preset condition, a turn-off signal is output to the main drive switch Q1 and the second auxiliary switch Q3 to stop the relay from working. For example, the first preset condition can be that the power supply voltage value is greater than a preset voltage, and the preset voltage can be set based on the actual situation.

[0035] In one possible embodiment, the main drive switch Q1, the first auxiliary switch Q2, and the second auxiliary switch Q3 can be transistors or other MOSFETs. For example, when a transistor is used, the current input terminal can be the collector, the current output terminal can be the emitter, and the control terminal can be the base.

[0036] In one possible embodiment, at the initial power-on moment, the control unit 120 outputs a conduction signal to turn on the main drive switch Q1, enabling the relay to work normally, and also turns on the second auxiliary switch Q3, causing the first auxiliary switch Q2 to turn off.

[0037] It should be noted that the first auxiliary switch Q2 has the opposite conduction logic to the main drive switch Q1, and under normal circumstances, one is on and the other is off.

[0038] With the above circuit structure, if the power supply voltage is abnormal, such as in the case of overvoltage, the control unit 120 outputs a shutdown signal, causing the main drive switch Q1 to fail. However, since the main drive switch Q1 may be short-circuited due to breakdown between the current input and current output terminals, it cannot work properly. This causes the relay JK1 to remain energized, and the contacts cannot disconnect properly. The abnormal operation of the relay JK1 will cause the circuit to malfunction. With the above circuit structure, through the auxiliary shutdown circuit 110, the control unit 120 sends a shutdown signal to the second auxiliary switch Q3, causing the second auxiliary switch Q3 to turn off and the first auxiliary switch Q2 to turn on, thereby short-circuiting the relay JK1, causing the relay JK1 to lose power supply, and the contacts can disconnect properly to cut off the circuit. The reliability of the circuit is improved by designing a safety redundancy auxiliary shutdown circuit 110.

[0039] Figure 2 A second schematic diagram of a relay drive circuit according to an embodiment of this disclosure is shown, as follows: Figure 2 As shown, the relay drive circuit 200 in Figure 1 In addition to this, it also includes: diagnostic sampling circuit 210.

[0040] One end of the diagnostic sampling circuit 210 is connected to the current input terminals of the relay JK1 and the main drive switch Q1, respectively; the other end of the diagnostic sampling circuit 210 is connected to the control unit 120.

[0041] In one possible embodiment, the control unit 120 is further configured to acquire the voltage value of the diagnostic sampling point at the initial power-on moment, and if the voltage value of the diagnostic sampling point does not meet the second preset condition, lock the system and issue an alarm signal.

[0042] For example, an alarm can be triggered by sound and light or by sending feedback to a host computer.

[0043] Through the above Figure 2In the circuit structure described above, at the initial power-on moment, the control power supply 120 can first judge based on the voltage value of the diagnostic sampling point obtained by the diagnostic sampling circuit 210. If the voltage value of the diagnostic sampling point is abnormal, an alarm signal is issued. This process is specifically sampling for the problem that it is impossible to determine if the main drive switch Q1 is broken down. This is because if the main drive switch Q1 is broken down at the moment of power-on, but under normal operation, the control unit 120 issues a conduction signal and the relay JK1 is normally powered on, the entire circuit is in the state of running with the fault of the main drive switch Q1 being broken down. Therefore, by detecting the voltage value between the main drive switch Q1 and the relay JK1 through the above-mentioned diagnostic sampling circuit, the relay drive circuit is prevented from running with a fault, realizing zero-risk fault start-up, which can improve the reliability of the overall circuit.

[0044] In one possible embodiment, the voltage value of the diagnostic sampling point does not meet the second preset condition, that is, the voltage value of the diagnostic sampling point is less than 0.5V.

[0045] In one possible embodiment, the control unit 120 is further configured to, at the initial power-on moment, if the voltage value of the diagnostic sampling point meets the third preset condition, output a turn-on signal to the main drive switch Q1 and the second auxiliary switch Q3 so that the relay JK1 starts working.

[0046] If the control unit 120 detects that the voltage value of the diagnostic sampling point is not abnormal, it can output a normal conduction signal to enable the relay JK1 to work.

[0047] In one possible embodiment, the third preset condition is that the voltage value at the diagnostic sampling point is greater than a preset multiple of the power supply voltage value. For example, the third preset condition could be that the voltage value at the diagnostic sampling point is greater than 0.9Vcc. The multiple can be set according to actual conditions, and this embodiment does not impose a specific limitation. Vcc is the voltage value of the DC voltage source, which is also the power supply voltage value of the power supply circuit.

[0048] In one possible embodiment, if the voltage value detected at the sampling point is greater than 0.5V and less than 0.9Vcc, it is determined to be "drive abnormality / undervoltage fault", the system is immediately locked and an alarm is triggered (startup is prohibited).

[0049] It should be noted that during the initial power-on process, before the control unit 120 outputs the conduction signal while judging the voltage value of the diagnostic sampling point, relay JK1 is short-circuited by the first auxiliary switch Q2. At this time, relay JK1 is not working. After the conduction signal is output, the main drive switch Q1 and the second auxiliary switch Q3 are turned on. After the second auxiliary switch Q3 is turned on, it will drive the control terminal of the first auxiliary switch Q2, causing the first auxiliary switch Q2 to be turned off, stopping the short circuit of relay JK1, and thus enabling relay JK1 to work normally.

[0050] In one possible embodiment, after the overall circuit enters the working state, the diagnostic sampling circuit 210 can also continuously sample the diagnostic sampling points, and the control unit 120 continuously detects the voltage value of the diagnostic sampling points to avoid the overall circuit running with the fault after the main drive switch Q1 is broken down, thereby improving the reliability of the overall circuit.

[0051] In one possible embodiment, at the initial power-on moment, the control unit 120 can also perform overvoltage detection, that is, obtain the power supply voltage value of the DC voltage source of the power supply circuit, and determine whether the power supply voltage value meets the first preset condition at the initial power-on moment.

[0052] In one possible embodiment, the power supply circuit includes a DC voltage source and a constant current drive circuit.

[0053] Figure 3 The third schematic diagram of a relay drive circuit according to an embodiment of this disclosure is shown, as follows: Figure 3 As shown, in Figure 1 Based on this, the power supply circuit 130 includes: a DC voltage source Vcc and a constant current drive circuit 131.

[0054] The constant current drive circuit 131 includes: a first constant current drive switch Q4, a second constant current drive switch Q5, a first resistor R1, a second resistor R2, and a first diode VD1.

[0055] The cathode of the first diode VD1 is connected between one end of the relay JK1 and the current input terminal of the main drive switch Q1. The anode of the first diode VD1 is connected to the other end of the relay JK1, the current output terminal of the first constant current drive switch Q4, and one end of the first resistor R1.

[0056] The other end of the first resistor R1 is connected to the control terminal of the first constant current drive switch Q4 and the current output terminal of the second constant current drive switch Q5, respectively. The current input terminal of the first constant current drive switch Q4 is connected to one end of the second resistor R2 and the control terminal of the second constant current drive switch Q5, respectively.

[0057] The other end of the second resistor R2 and the current input terminal of the second constant current drive switch Q5 are connected to the DC voltage source Vcc of the power supply circuit.

[0058] The current input terminal of the first auxiliary switch Q2 is connected between one end of the relay JK1 and one end of the first resistor R1.

[0059] In one possible embodiment, the first constant current drive switch Q4 and the second constant current drive switch Q5 can be transistors or other MOSFETs, for example, when they are transistors, the current input terminal can be the collector, the current output terminal can be the emitter, and the control terminal can be the base.

[0060] Through the constant current drive circuit 131 with the above circuit structure, during the process of the control unit 120 outputting the conduction signal to make the whole circuit work normally, the maximum current of the limit relay drive circuit 300 can be put into constant current drive mode.

[0061] In one possible embodiment, the maximum current of the constant current drive circuit 131 is configured based on the first resistor. Exemplarily, the maximum current can be... .

[0062] In one possible embodiment, Figure 4 The fourth schematic diagram of a relay drive circuit according to an embodiment of this disclosure is shown. Figure 4 As shown, a resistor for the protection circuit is designed in the relay drive circuit 400 to protect the auxiliary shutdown circuit 110 and the main drive switch Q1, reducing the risk of overcurrent breakdown. Specifically, in... Figure 4 The relay drive circuit 400 also includes the specific structure of the power supply circuit and the diagnostic sampling circuit.

[0063] like Figure 4 As shown, the relay drive circuit 400 also includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a second diode VD2, a seventh resistor R7, and an eighth resistor R8.

[0064] The third resistor R3 is connected between the DC voltage source Vcc of the power supply circuit and the control terminal of the first auxiliary switch Q2, and between the DC voltage source Vcc of the power supply circuit and the current input terminal of the second auxiliary switch Q3.

[0065] The fourth resistor R4 is connected between the control terminal and the current output terminal of the first auxiliary switch Q2.

[0066] The cathode of the second diode VD2 is connected to the current output terminal of the first auxiliary switch Q2 and the fourth resistor R4, and the anode of the second diode VD2 is connected between the relay JK1 and the current input terminal of the main drive switch Q1.

[0067] The fifth resistor R5 is connected between the control terminal and the current output terminal of the second auxiliary switch Q3, and the sixth resistor R6 is connected between the control terminal of the second auxiliary switch Q3 and the control unit 120. That is, one end of the sixth resistor R6 is connected to the control terminal of the second auxiliary switch Q3, and the other end of the sixth resistor R6 is connected between the control unit 120 and the seventh resistor R7.

[0068] Among them, the seventh resistor R7 is connected between the control terminal of the main drive switch Q1 and the control unit 120, and the control terminal of the main drive switch Q1 is grounded through the eighth resistor R8.

[0069] With the above circuit structure, the control unit 120 can perform power-on pre-checks at the initial power-on moment, such as fault detection and overvoltage detection of the main drive switch Q1, to avoid the overall circuit from operating with faults. At the initial power-on moment, the main drive switch Q1, the second auxiliary switch Q3, the first constant current drive switch Q4, and the second constant current drive switch Q5 are in the off state, and the first auxiliary switch Q2 is in the on state, short-circuiting the relay JK1 to ensure that the coil of the relay JK1 is in the off state.

[0070] After the detection is passed, a conduction signal is output, which turns on the main drive switch Q1. The constant current drive circuit 131 makes the coil current of relay JK1 constant, turns on the second auxiliary switch Q3 and enables the first auxiliary switch Q2 to be turned off, thereby making relay JK1 enter the constant current drive state.

[0071] During the operation of the relay drive circuit 400, the voltage value of the diagnostic sampling point can be continuously detected to ensure the safe operation of the main drive switch Q1, improve the overall circuit reliability, and continuously detect the value of Vcc in the power supply circuit for overvoltage protection. Through the constant current drive circuit, the randomness and low reliability of the relay operation when the input voltage fluctuates can be avoided, thereby improving the reliability of the relay.

[0072] When overvoltage occurs or other conditions arise, the control unit can output a shutdown signal upon request, causing the main drive switch Q1 and the second auxiliary switch Q3 to turn off. Even if Q1 is damaged, the first auxiliary switch Q2 can still enable the circuit relay JK1, thereby stopping the relay JK1 from working. This prevents circuit safety issues caused by a single point of failure of the main drive switch Q1, achieving a double shutdown of the relay JK1 and improving the reliability of the relay drive circuit 400. The above circuit structure can achieve surge protection, preventing the coil temperature from rising during overvoltage, and avoiding relay aging failure or other malfunctions.

[0073] Furthermore, although the above circuit structure continuously monitors the diagnostic sampling points and can promptly detect and replace the main drive switch Q1 when it is broken down, in cases where it is inconvenient or impossible to replace the main drive switch Q1 in a timely manner, the above circuit structure can still ensure that the contacts of the relay JK1 are triggered normally, thus ensuring circuit safety.

[0074] In one possible embodiment, the relay drive circuit of the above circuit structure has high reliability with fault self-shortage and multiple shutdown protection. The relay drive circuit in this embodiment can be used in a variety of different application scenarios and is not limited to its scope of use. For example, it can be used in scenarios such as safety control and rail transit signaling systems.

[0075] Figure 5 This disclosure illustrates a control method for a relay drive circuit, such as... Figure 5 As shown, this method, which can be used in the circuit structure described above, includes the following steps: S502: Obtain the power supply voltage value of the power supply circuit.

[0076] S504: If the power supply voltage does not meet the first preset condition, a turn-off signal is output to the main drive switch and the second auxiliary switch to stop the relay from working.

[0077] In one possible embodiment, the method may further perform the following steps, including: acquiring the voltage value of the diagnostic sampling point at the initial power-on moment; and issuing an alarm signal if the voltage value of the diagnostic sampling point does not meet a second preset condition.

[0078] In one possible embodiment, the method may also perform the following steps, including: at the initial power-on moment, if the voltage value of the diagnostic sampling point meets a third preset condition, then output a turn-on signal to the main drive switch and the second auxiliary switch to enable the relay to start working.

[0079] The embodiments of the above execution steps and the embodiments of the above circuit structure have been described, and will not be repeated here.

[0080] In the embodiments disclosed herein, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The concepts of "first," "second," etc., mentioned in this disclosure are only used to distinguish different devices, modules, or units and are not used to define the order of functions performed by these devices, modules, or units or their interdependencies.

[0081] In this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0082] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein.

[0083] This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A relay drive circuit, characterized in that, include: Relays, main drive switching transistors, auxiliary shutdown circuits, control units, and power supply circuits; The auxiliary shutdown circuit includes: a first auxiliary switch and a second auxiliary switch; The current input terminal of the main drive switch is connected to the relay, and then connected to the power supply circuit via the relay. The control terminal of the main drive switch is connected to the control unit, and the current output terminal of the main drive switch is grounded. The current output terminal and current input terminal of the first auxiliary switch are connected in parallel to the two ends of the relay. The control terminal of the first auxiliary switch is connected to the current input terminal of the second auxiliary switch and the power supply circuit. The current output terminal of the second auxiliary switch is grounded. The control terminal of the second auxiliary switch is connected to the control unit. The control unit is used to obtain the power supply voltage value of the power supply circuit. If the power supply voltage value does not meet the first preset condition, it outputs a shutdown signal to the main drive switch and the second auxiliary switch to stop the relay from working.

2. The relay drive circuit according to claim 1, characterized in that, Also includes: Diagnostic sampling circuit; One end of the diagnostic sampling circuit is connected to the current input terminals of the relay and the main drive switch, respectively; the other end of the diagnostic sampling circuit is connected to the control unit. The control unit is also used to acquire the voltage value of the diagnostic sampling point at the initial power-on moment, and if the voltage value of the diagnostic sampling point does not meet the second preset condition, an alarm signal is issued.

3. The relay drive circuit according to claim 1, characterized in that, The condition that the second preset condition is not met is that the voltage value of the diagnostic sampling point is less than 0.5V.

4. The relay drive circuit according to claim 2, characterized in that, Also includes: The control unit is also configured to, at the initial power-on moment, if the voltage value of the diagnostic sampling point meets the third preset condition, output a conduction signal to the main drive switch and the second auxiliary switch to enable the relay to start working.

5. The relay drive circuit according to claim 4, characterized in that, The third preset condition is that the voltage value of the diagnostic sampling point is greater than a preset multiple of the power supply voltage value.

6. The relay drive circuit according to claim 1, characterized in that, The power supply circuit includes a DC voltage source and a constant current drive circuit.

7. The relay drive circuit according to claim 6, characterized in that, The constant current driving circuit includes: a first constant current driving switch, a second constant current driving switch, a first resistor, a second resistor, and a first diode; The cathode of the first diode is connected between one end of the relay and the current input terminal of the main drive switch, and the anode of the first diode is connected to the other end of the relay, the current output terminal of the first constant current drive switch, and one end of the first resistor. The other end of the first resistor is connected to the control terminal of the first constant current drive switch and the current output terminal of the second constant current drive switch, respectively. The current input terminal of the first constant current drive switch is connected to one end of the second resistor and the control terminal of the second constant current drive switch, respectively. The other end of the second resistor and the current input terminal of the second constant current drive switch are connected to the DC voltage source of the power supply circuit.

8. The relay drive circuit according to claim 1, characterized in that, The auxiliary shutdown circuit also includes: a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a second diode; The third resistor is connected between the power supply circuit and the control terminal of the first auxiliary switch, and between the power supply circuit and the current input terminal of the second auxiliary switch. The fourth resistor is connected between the control terminal and the current output terminal of the first auxiliary switch. The cathode of the second diode is connected to the current output terminal of the first auxiliary switch and the fourth resistor, and the anode of the second diode is connected between the relay and the current input terminal of the main drive switch. The fifth resistor is connected between the control terminal and the current output terminal of the second auxiliary switch, and the sixth resistor is connected between the control terminal of the second auxiliary switch and the control unit.

9. The relay drive circuit according to claim 1, characterized in that, Also includes: The seventh and eighth resistors; the control terminal of the main drive switch is grounded via the eighth resistor; The seventh resistor is connected between the control terminal of the main drive switch and the control unit.

10. A control method for a relay drive circuit, characterized in that, For use in the relay drive circuit as described in claims 1-10, the method includes: Obtain the power supply voltage value of the power supply circuit; If the power supply voltage value does not meet the first preset condition, a turn-off signal is output to the main drive switch and the second auxiliary switch to stop the relay from working.

11. The method according to claim 10, characterized in that, The method further includes: At the initial power-on moment, acquire the voltage value of the diagnostic sampling point; If the voltage value at the diagnostic sampling point does not meet the second preset condition, an alarm signal will be issued.

12. The method according to claim 11, characterized in that, The method further includes: At the initial power-on moment, if the voltage value of the diagnostic sampling point meets the third preset condition, a conduction signal is output to the main drive switch and the second auxiliary switch to enable the relay to start working.

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