A strong anti-interference, shoot-through-resistant single-coil magnetic latching relay drive circuit
By optimizing the analog signal triggering path and the shoot-through protection mechanism, and using PNP and NPN transistors to form a bridge arm circuit, the problems of weak anti-interference capability and insufficient shoot-through protection of traditional magnetic latching relay drive circuits are solved, realizing a high-reliability and low-cost magnetic latching relay drive circuit.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FOSHAN HECHU ENERGY TECH CO LTD
- Filing Date
- 2025-08-15
- Publication Date
- 2026-07-03
AI Technical Summary
Traditional magnetic latching relay drive circuits have weak anti-interference capabilities, are susceptible to electromagnetic interference leading to false triggering, lack shoot-through protection, pose safety hazards, and are costly and complex.
An optimized analog signal triggering path and shoot-through protection mechanism are adopted. PNP and NPN transistors are used to form a bridge arm circuit to achieve anti-interference and shoot-through functions, simplifying the circuit structure.
It improves the control accuracy and stability of relays, prevents power supply short circuits, reduces hardware costs, simplifies circuit layout, and facilitates mass production and maintenance.
Smart Images
Figure CN224459767U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of magnetic latching relay technology, and in particular to a single-coil magnetic latching relay drive circuit with strong anti-interference and anti-short-circuit protection. Background Technology
[0002] A magnetic latching relay is an automatic switch that automatically connects and disconnects circuits. Due to its ability to maintain a conducting or disconnected state without continuous energization, magnetic latching relays are widely used in new energy industries, instrumentation, and industrial control. Traditional magnetic latching relay drive circuits typically rely on analog signal triggering control. For example, a control circuit disclosed in Chinese patent CN 212570855 U uses transistors (first to fourth) and resistors to form a trigger circuit. Under the drive of an analog signal, a forward or reverse voltage is applied to the relay coil to achieve the connection or disconnection of the relay contacts. Such circuits have gained some popularity in instrumentation due to their simple structure, high reliability, and ease of integration. However, existing technologies still have significant shortcomings:
[0003] Weak anti-interference capability: Pure analog signal triggering circuits are sensitive to electromagnetic interference (EMI) and noise, especially in strong interference environments such as new energy equipment (such as photovoltaic inverters and energy storage systems). The signal is easily interfered with, leading to false triggering, which in turn causes the relay to malfunction, posing a safety hazard.
[0004] Reliability risks: Some traditional circuits lack shoot-through protection. When the drive signal is abnormal or a component fails, the VCC 12V power supply may be directly connected to ground (GND), causing a short circuit risk and reducing system stability.
[0005] Cost and complexity issues: To improve performance, some companies currently use dedicated driver chips (such as DRV8870DDA). Although this enhances control accuracy, such chips are expensive and require more external components (such as capacitors, resistors, protection diodes, etc.), which increases the overall cost of the solution and the complexity of the circuit layout, making it difficult for mass production and maintenance.
[0006] In summary, developing a magnetic latching relay drive circuit that combines high reliability, strong anti-interference capability, low cost, and simplified peripheral structure has become a technical challenge that the industry urgently needs to solve. Utility Model Content
[0007] The purpose of this invention is to provide a single-coil magnetic latching relay drive circuit with strong anti-interference and anti-short-circuit protection. By optimizing the analog signal trigger path and adding an anti-short-circuit protection mechanism, the hardware cost is reduced and the environmental adaptability is improved while ensuring circuit stability.
[0008] To achieve the above objectives, this utility model provides the following solution:
[0009] A strong anti-interference, shoot-through-resistant single-coil magnetic latching relay drive circuit includes a first bridge arm circuit and a second bridge arm circuit; the first bridge arm circuit includes transistors Q11, Q13, Q15, and Q17, and the second bridge arm circuit includes transistors Q12, Q14, Q16, and Q18;
[0010] The emitters of transistors Q11 and Q12 are both connected to the power supply VCC12V;
[0011] The base of transistor Q11 is connected to power supply VCC12V through resistor R21, and the collector is connected to the collector of transistor Q13 through resistor R13; the base of transistor Q12 is connected to power supply VCC12V through resistor R22, and the collector is connected to the collector of transistor Q14 through resistor R15.
[0012] The base of transistor Q13 is connected to the collector of transistor Q17, and is connected to the collector of transistor Q15 through resistor R14; the base of transistor Q14 is connected to the collector of transistor Q18, and is connected to the collector of transistor Q16 through resistor R17.
[0013] The collector of transistor Q15 is connected to the base of transistor Q18 through resistor R23; the collector of transistor Q16 is connected to the base of transistor Q17 through resistor R24.
[0014] The emitter of transistor Q17 and the emitter of transistor Q18 are grounded;
[0015] The base of transistor Q15 is connected to the first control signal terminal RELAY_ON through resistor R12, and the base of transistor Q16 is connected to the second control signal terminal RELAY_OFF through resistor R16.
[0016] The collector of transistor Q11 is connected to the negative control terminal RLY- of the magnetic latching relay coil through resistor R13, and the base of transistor Q12 is connected to the negative control terminal RLY- of the magnetic latching relay coil through resistor R19.
[0017] The collector of transistor Q12 is connected to the positive control terminal RLY+ of the magnetic latching relay coil via resistor R15, and the base of transistor Q11 is connected to the negative control terminal RLY+ of the magnetic latching relay coil via resistor R20.
[0018] Furthermore, the emitters of transistors Q15 and Q16 are respectively connected to the power supply VCC 3.3V.
[0019] Furthermore, the base of transistor Q15 is connected to power supply VCC 3.3V through resistor R11, and the base of transistor Q16 is connected to power supply VCC 3.3V through resistor R18.
[0020] Furthermore, resistors R12 and R16 are grounded via capacitors.
[0021] Furthermore, the emitters of transistor Q13 and transistor Q14 are grounded respectively.
[0022] Furthermore, transistors Q11, Q15, Q12, and Q16 are PNP transistors; transistors Q13, Q17, Q14, and Q18 are NPN transistors.
[0023] Furthermore, the first bridge arm circuit and the second bridge arm circuit are arranged symmetrically.
[0024] According to the specific embodiments provided by this utility model, the single-coil magnetic latching relay drive circuit with strong anti-interference and anti-straight-through characteristics provided by this utility model discloses the following technical effects:
[0025] (1) Reliably prevent power supply short circuit and protect device safety: The transistors Q17 and Q18 form a short circuit prevention circuit. When a certain output control path (such as the RLY- path) is activated (e.g., RELAYON is effective), Q17 or Q18 will immediately clamp the base voltage of the core driver transistor (Q13 or Q14) of another output control path (such as the RLY+ path) to a low level (close to 0V), forcing it to be reliably cut off. This avoids the risk of Q11 and Q13 being turned on at the same time or Q12 and Q14 being turned on at the same time due to abnormal control signals or interference, thus improving the reliability of the circuit.
[0026] (2) Effectively suppress interference signals and prevent malfunctions: The anti-interference unit is formed by transistors Q15 and Q16, which enables the circuit to filter short-time pulse interference and noise on the input control signals (RELAY_ON, RELAY_OFF). Only effective control signals with a certain amplitude and duration can trigger Q15 or Q16 to conduct, thereby driving the subsequent circuit to operate. This reduces the possibility of the relay being opened or closed by interference signals or experiencing state jitter, and improves the accuracy and stability of the control.
[0027] (3) Achieve reliable bidirectional drive of the magnetic latching relay coil: The positive output control circuit is constructed by transistors Q12 and Q13, and the negative output control circuit is constructed by transistors Q11 and Q14. The high and low level combinations of the RELAY_ON and RELAY_OFF signals are precisely controlled to reliably establish a positive or reverse voltage difference between the RLY+ and RLY- terminals, providing a clear and stable drive direction control signal (RLY+ and RLY-) for the magnetic latching relay coil, ensuring that the relay can be correctly set or reset.
[0028] (4) Simplify circuit structure and reduce circuit cost: Based on analog signal triggering magnetic latching relay control, pure analog signal triggering control has high reliability. Only a few transistors, resistors and capacitors are used, and the overall cost is low. It realizes stable and reliable control of magnetic latching relay, with a very high cost performance. The circuit is simple and easy to implement, which facilitates the widespread application of magnetic latching relay in instruments and meters and has good application prospects. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments 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.
[0030] Figure 1 This is a structural diagram of the drive circuit for a single-coil magnetic latching relay with strong anti-interference and anti-short-circuit capability according to an embodiment of this utility model. Detailed Implementation
[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0032] The purpose of this invention is to provide a single-coil magnetic latching relay drive circuit with strong anti-interference and anti-short-circuit protection. By optimizing the analog signal trigger path and adding an anti-short-circuit protection mechanism, the hardware cost is reduced and the environmental adaptability is improved while ensuring circuit stability.
[0033] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0034] like Figure 1 As shown, this utility model provides a single-coil magnetic latching relay drive circuit with strong anti-interference and anti-shoo-through characteristics, including: a first bridge arm circuit and a second bridge arm circuit; the first bridge arm circuit includes transistors Q11, Q13, Q15 and Q17, and the second bridge arm circuit includes transistors Q12, Q14, Q16 and Q18;
[0035] The emitters of transistors Q11 and Q12 are both connected to the power supply VCC12V;
[0036] The base of transistor Q11 is connected to power supply VCC12V through resistor R21, and the collector is connected to the collector of transistor Q13 through resistor R13; the base of transistor Q12 is connected to power supply VCC12V through resistor R22, and the collector is connected to the collector of transistor Q14 through resistor R15.
[0037] The base of transistor Q13 is connected to the collector of transistor Q17, and is connected to the collector of transistor Q15 through resistor R14; the base of transistor Q14 is connected to the collector of transistor Q18, and is connected to the collector of transistor Q16 through resistor R17; the emitters of transistor Q13 and transistor Q14 are grounded respectively.
[0038] The collector of transistor Q15 is connected to the base of transistor Q18 through resistor R23; the collector of transistor Q16 is connected to the base of transistor Q17 through resistor R24; the emitters of transistors Q15 and Q16 are connected to power supply VCC 3.3V; the base of transistor Q15 is connected to power supply VCC 3.3V through resistor R11, and the base of transistor Q16 is connected to power supply VCC 3.3V through resistor R18.
[0039] The emitter of transistor Q17 and the emitter of transistor Q18 are grounded;
[0040] The base of transistor Q15 is connected to the first control signal terminal RELAY_ON through resistor R12, and the base of transistor Q16 is connected to the second control signal terminal RELAY_OFF through resistor R16. Resistors R12 and R16 are grounded through capacitors. The first control signal terminal RELAY_ON and the second control signal terminal RELAY_OFF are connected to the MCU's I / O pins, and the MCU provides high and low level control signals.
[0041] The collector of transistor Q11 is connected to the negative control terminal RLY- of the magnetic latching relay coil through resistor R13, and the base of transistor Q12 is connected to the negative control terminal RLY- of the magnetic latching relay coil through resistor R19.
[0042] The collector of transistor Q12 is connected to the positive control terminal RLY+ of the magnetic latching relay coil via resistor R15, and the base of transistor Q11 is connected to the negative control terminal RLY+ of the magnetic latching relay coil via resistor R20.
[0043] Specifically, transistors Q11, Q15, Q12, and Q16 are PNP transistors; transistors Q13, Q17, Q14, and Q18 are NPN transistors.
[0044] Specifically, the first bridge arm circuit and the second bridge arm circuit can be arranged symmetrically.
[0045] In the aforementioned driving circuit, transistors Q15 and Q16 primarily function as anti-interference devices, effectively filtering out interference signals; transistors Q17 and Q18 function as anti-shoot-through devices, preventing transistor damage caused by simultaneous conduction of Q12 and Q13, or Q11 and Q14; transistors Q13 and Q12 control the RLY+ circuit, and transistors Q14 and Q11 control the RLY- circuit.
[0046] The control logic of the single-coil magnetic latching relay drive circuit with strong anti-interference and anti-short-circuit protection is shown in Table 1, and its working principle is as follows:
[0047] When RELAY_OFF is high, transistor Q16 is not working; simultaneously, when RELAY_ON is low, the voltage of PNP transistor Q15 is low. be When the voltage is less than 0V, the emitter and collector pins of Q15 are conducting. At this time, the voltage of NPN transistor Q13 is... be With voltage >0V, pins e and c of transistor Q13 are conducting, and RLY- is approximately 0V. At this time, the voltage at pin b of transistor Q12 is 0V, and the voltage at pin e is 12V, i.e., V. be When the voltage is less than 0V, the emitter and collector pins of transistor Q12 are turned on, and RLY+ is 12V. A positive voltage is applied to the coil of the magnetic latching relay, and the magnetic latching relay is activated.
[0048] When RELAY_ON is high, transistor Q15 is not working; simultaneously, when RELAY_OFF is low, the voltage of PNP transistor Q16 is high. be When the voltage is less than 0V, the emitter and collector pins of Q16 are conducting. At this time, the voltage of the NPN transistor Q14 is less than 0V. beWith voltage >0V, pins e and c of transistor Q14 are conducting, and RLY+ is approximately 0V. At this time, the voltage at pin b of transistor Q11 is 0V, and the voltage at pin e is 12V, i.e., V. be When the voltage is less than 0V, the emitter and collector pins of transistor Q11 are conducting. RLY- is 12V, which applies a negative voltage to the coil of the magnetic latching relay, causing the magnetic latching relay to disconnect.
[0049] When RELAY_ON is low, transistor Q15 is working, and at this time, the V of NPN transistor Q13 is low. be With voltage >0V, pins e and c of transistor Q13 are conducting. At this time, the voltage at pin b of transistor Q12 is 0V, and the voltage at pin e is 12V. Therefore, V be With voltage <0V, the emitter and collector pins of transistor Q12 are conducting, and RLY+ is 12V; simultaneously, RELAY_OFF is low, and the voltage of PNP transistor Q16 is low. be With voltage <0V, pins e and c of transistor Q16 are conducting, pins e and c of transistor Q14 are conducting, pins e and c of transistor Q11 are conducting, and RLY- is 12V. The voltage difference across the magnetic latching relay coil is 0, so the magnetic latching relay does not operate and remains in its current state.
[0050] Similarly, when RELAY_OFF is high, transistor Q16 does not work and RLY- is 0V; at the same time, when RELAY_ON is high, transistor Q15 does not work and RLY+ is 0V; the voltage difference across the magnetic latching relay coil is 0, the magnetic latching relay does not operate, and maintains the current state.
[0051] Table 1 Control Logic
[0052] RELAY_OFF RELAY_ON RLY+ / V RLY- / V Magnetic latching relay status 1 0 12 0 suction 0 1 0 12 disconnect 0 0 12 12 Keep 1 1 12 12 Keep
[0053] Shoot protection function: This function prevents shoot-through between VCC12V power supply and GND. When RELAY_ON is low, the emitter and collector pins of transistor Q12 are connected. At this time, transistor Q18 will be blocked due to VCC12V power supply failure. be Since the voltage is greater than 0V, the collector and emitter pins are conducting, causing the voltage of transistor Q14 to be greater than 0V. be The voltage is clamped at around 0V, preventing Q12 and Q14 from conducting simultaneously, thus providing a shoot-through protection function.
[0054] When RELAY_OFF is low, the emitter and collector pins of transistor Q11 are turned on. At this time, transistor Q17 is turned on because V be Since the voltage is greater than 0V, the collector (c) and emitter (e) are conducting, making the voltage of Q13 V... be The voltage is clamped at around 0V, preventing Q11 and Q13 from conducting simultaneously, thus providing a shoot-through protection function.
[0055] The remaining technical features in this embodiment can be flexibly selected by those skilled in the art to meet different specific practical needs. However, it is obvious to those skilled in the art that these specific details are not necessary to implement this utility model. In other instances, to avoid obscuring this utility model, well-known components, structures, or parts are not specifically described, and all are within the scope of technical protection defined by the claims of this utility model.
[0056] Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this utility model should be protected within the scope of the appended claims. In the above description, numerous specific details have been set forth to provide a thorough understanding of this utility model. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement this utility model. In other instances, to avoid obscuring this utility model, well-known techniques, such as specific construction details, operating conditions, and other technical conditions, have not been specifically described.
[0057] This document uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. Furthermore, those skilled in the art will recognize that, based on the ideas of this utility model, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this utility model.
Claims
1. A strong anti-interference type anti-direct through single-coil magnetic latching relay drive circuit, characterized in that, include: First bridge arm circuit and second bridge arm circuit; the first bridge arm circuit includes transistors Q11, Q13, Q15 and Q17, and the second bridge arm circuit includes transistors Q12, Q14, Q16 and Q18. The emitters of transistors Q11 and Q12 are both connected to the power supply VCC12V; The base of transistor Q11 is connected to power supply VCC12V through resistor R21, and the collector is connected to the collector of transistor Q13 through resistor R13; the base of transistor Q12 is connected to power supply VCC12V through resistor R22, and the collector is connected to the collector of transistor Q14 through resistor R15. The base of transistor Q13 is connected to the collector of transistor Q17, and is connected to the collector of transistor Q15 through resistor R14; the base of transistor Q14 is connected to the collector of transistor Q18, and is connected to the collector of transistor Q16 through resistor R17. The collector of transistor Q15 is connected to the base of transistor Q18 through resistor R23; the collector of transistor Q16 is connected to the base of transistor Q17 through resistor R24. The emitter of transistor Q17 and the emitter of transistor Q18 are grounded; The base of transistor Q15 is connected to the first control signal terminal RELAY_ON through resistor R12, and the base of transistor Q16 is connected to the second control signal terminal RELAY_OFF through resistor R16. The collector of transistor Q11 is connected to the negative control terminal RLY- of the magnetic latching relay coil through resistor R13, and the base of transistor Q12 is connected to the negative control terminal RLY- of the magnetic latching relay coil through resistor R19. The collector of transistor Q12 is connected to the positive control terminal RLY+ of the magnetic latching relay coil via resistor R15, and the base of transistor Q11 is connected to the negative control terminal RLY+ of the magnetic latching relay coil via resistor R20.
2. The strong anti-interference type anti-direct-drive single-coil magnetic latching relay drive circuit according to claim 1, characterized in that, The emitters of transistors Q15 and Q16 are connected to the power supply VCC 3.3V.
3. The single-coil magnetic latching relay drive circuit with strong anti-interference and anti-short-circuit protection according to claim 2, characterized in that, The base of transistor Q15 is connected to power supply VCC 3.3V through resistor R11, and the base of transistor Q16 is connected to power supply VCC 3.3V through resistor R18.
4. The single-coil magnetic latching relay drive circuit with strong anti-interference and anti-short-circuit protection according to claim 1, characterized in that, The resistors R12 and R16 are grounded through capacitors.
5. The single-coil magnetic latching relay drive circuit with strong anti-interference and anti-short-circuit protection according to claim 1, characterized in that, The emitters of transistors Q13 and Q14 are grounded respectively.
6. The strong anti-interference type anti-direct-drive single-coil magnetic latching relay drive circuit according to claim 1, characterized in that, Transistors Q11, Q15, Q12, and Q16 are PNP type transistors; transistors Q13, Q17, Q14, and Q18 are NPN type transistors.
7. The strong anti-interference type anti-direct-drive single-coil magnetic latching relay drive circuit according to claim 1, characterized in that, The first bridge arm circuit and the second bridge arm circuit are arranged symmetrically.