A high voltage relay drive circuit

Abstract

This utility model discloses a high-voltage relay drive circuit, including: a dual power supply module, a relay module, a rated voltage control branch, a holding voltage isolation branch, a grounding control branch, a freewheeling protection branch, and a filtering module. Through the dual power supply switching, the rated power supply VCC1 ensures rapid relay engagement, while the holding power supply VCC2 (40%~60% of VCC1) supports low-power holding, resolving the contradiction between rapid engagement and long-term low power consumption. Furthermore, reduced coil heating extends relay life and improves system efficiency. The freewheeling protection branch, with diode D2 and Zener diode D3 connected in series, overcomes the limitations of traditional single-diode freewheeling current decay and delayed contact opening. The Zener diode clamping accelerates current discharge, significantly shortening contact opening time, suppressing jitter inrush current, and reducing the risk of contact sticking in high-voltage scenarios. This adapts to the design requirements of different application scenarios, enhances power supply ripple resistance, and improves circuit reliability and versatility.

Description

Technical Field

[0001] This utility model relates to the field of relay drive circuit technology, specifically to a high-voltage relay drive circuit. Background Technology

[0002] To reduce the power consumption of high-voltage relay coils, most manufacturers use a different holding voltage than the rated voltage for their high-voltage relay coils; the holding voltage is generally lower than the rated voltage. While using the rated voltage to power the coil is theoretically feasible, prolonged operation of the relay coil at the rated voltage results in high power consumption and high temperature, impacting both the overall system efficiency and the relay's lifespan. Existing high-voltage relay drive circuits typically employ a driving method powered by the rated voltage.

[0003] When a high-voltage relay disconnects, in order to prevent overvoltage caused by sudden changes in coil current, an anti-parallel diode needs to be added across the coil as a freewheeling circuit. Although adding an anti-parallel diode can suppress overvoltage, it will slow down the relay disconnection speed. In high-voltage applications, this can easily cause relay contact bounce, resulting in a large current surge, which may lead to relay contact sticking. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model designs a high-voltage relay driving circuit, comprising: a dual power supply module: including a rated power supply VCC1 and a holding power supply VCC2; a relay module: including a relay K1, node A, and node B; the first connection terminal of relay K1 is connected to node A, and the second connection terminal of relay K1 is connected to node B; a rated voltage control branch: including a MOSFET Q1, a pull-up resistor R1, a drive resistor R2, and a control terminal CH1; the drain of MOSFET Q1 is connected to the rated power supply VCC1, the gate is connected to the control terminal CH1 through the drive resistor R2, and the source is connected to node A, wherein the gate of MOSFET Q1 is also connected to the rated power supply VCC1 through the pull-up resistor R1; a holding voltage isolation branch: including a diode D1, the anode of diode D1 is connected to the holding power supply VCC2, and the cathode is connected to node A; and a grounding control branch. Control branch: includes switching transistor Q2, pull-down resistor R3, drive resistor R4, and control terminal CH2; the first terminal of switching transistor Q2 is connected to node B, the second terminal is grounded, and the third terminal is connected to control terminal CH2 through drive resistor R4. The third terminal is also grounded through pull-down resistor R3. Freewheeling protection branch: includes diode D2 and Zener diode D3. The anode of diode D2 is connected to node B, and the cathode is connected to the cathode of Zener diode D3. The anode of Zener diode D3 is connected to node A. Filter module: includes first filter capacitor C1, second filter capacitor C2, third filter capacitor C3, and fourth filter capacitor C4. The first filter capacitor C1 is connected in parallel between the rated power supply VCC1 and ground. The second filter capacitor C2 is connected in parallel between the power supply VCC2 and ground. The third filter capacitor C3 is connected in parallel between node A and ground. The fourth filter capacitor C4 is connected in parallel between the third terminal of switching transistor Q2 and ground.

[0005] Preferably, the switching transistor Q2 is a transistor or a MOSFET.

[0006] Preferably, the switching transistor Q2 is an NPN transistor with the first terminal being the collector, the second terminal being the emitter, and the third terminal being the base.

[0007] Preferably, the switching transistor Q2 is an N-channel MOSFET, with the first terminal being the drain, the second terminal being the source, and the third terminal being the gate.

[0008] Preferably, the first filter capacitor C1, the second filter capacitor C2, the third filter capacitor C3, and the fourth filter capacitor C4 are all composed of multiple capacitors connected in parallel.

[0009] Preferably, the voltage of the rated power supply VCC1 is higher than the voltage of the holding power supply VCC2.

[0010] Preferably, the voltage of the power supply VCC2 is maintained at 40% to 60% of the voltage of the rated power supply VCC1.

[0011] Compared with the closest existing technology, the beneficial effects of this utility model are as follows: 1. This utility model, through the dual power supply switching setting, ensures the relay engages quickly with the rated power supply VCC1, while maintaining the power supply VCC2 (40%~60% of VCC1) to support low power consumption. This not only solves the contradiction between rapid engagement and long-term low power consumption, but also extends the relay life and improves system energy efficiency due to reduced coil heating.

[0012] 2. The freewheeling branch of diode D2 and Zener diode D3 connected in series in this utility model breaks through the limitations of slow decay of freewheeling current and delayed contact opening of traditional single diodes. It utilizes Zener diode clamping to accelerate current discharge, significantly shortens contact opening time, suppresses jitter impact current, and reduces the risk of contact adhesion in high-voltage scenarios.

[0013] 3. In this utility model, the diode D1 in the voltage-holding branch achieves dual power supply isolation through reverse cutoff, avoiding switching crosstalk; the switching transistor Q2 is compatible with transistors or MOSFETs, and the filter module supports multiple capacitors in parallel, which not only adapts to the design requirements of different application scenarios, but also enhances the power supply's anti-ripple capability and improves the reliability and versatility of the circuit. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the high-voltage relay drive circuit of this utility model. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Example

[0016] like Figure 1As shown, this utility model provides a high-voltage relay drive circuit, including: a dual power supply module: including a rated power supply VCC1 and a holding power supply VCC2; a relay module: including a relay K1, node A and node B; the first connection terminal of relay K1 is connected to node A, and the second connection terminal of relay K1 is connected to node B; a rated voltage control branch: including a MOSFET Q1, a pull-up resistor R1, a drive resistor R2 and a control terminal CH1; the drain of MOSFET Q1 is connected to the rated power supply VCC1, the gate is connected to the control terminal CH1 through the drive resistor R2, and the source is connected to node A, wherein the gate of MOSFET Q1 is also connected to the rated power supply VCC1 through the pull-up resistor R1; a holding voltage isolation branch: including a diode D1, the anode of diode D1 is connected to the holding power supply VCC2, and the cathode is connected to node A; and a grounding control branch. The circuit includes a switching transistor Q2, a pull-down resistor R3, a drive resistor R4, and a control terminal CH2. The first terminal of the switching transistor Q2 is connected to node B, the second terminal is grounded, and the third terminal is connected to the control terminal CH2 through the drive resistor R4. The third terminal is also grounded through the pull-down resistor R3. The freewheeling protection branch includes a diode D2 and a Zener diode D3. The anode of the diode D2 is connected to node B, and the cathode is connected to the cathode of the Zener diode D3. The anode of the Zener diode D3 is connected to node A. The filtering module includes a first filter capacitor C1, a second filter capacitor C2, a third filter capacitor C3, and a fourth filter capacitor C4. The first filter capacitor C1 is connected in parallel between the rated power supply VCC1 and ground. The second filter capacitor C2 is connected in parallel between the power supply VCC2 and ground. The third filter capacitor C3 is connected in parallel between node A and ground. The fourth filter capacitor C4 is connected in parallel between the third terminal of the switching transistor Q2 and ground. By employing a dual-power supply switching configuration, the rated power supply VCC1 ensures rapid relay engagement, while the power supply VCC2 (40%~60% of VCC1) supports low-power maintenance. This resolves the conflict between rapid engagement and long-term low power consumption, and also extends relay life and improves system efficiency due to reduced coil heating. The freewheeling branch, with diode D2 and Zener diode D3 connected in series, overcomes the limitations of traditional single-diode freewheeling current decay and delayed contact opening. The Zener diode clamping accelerates current discharge, significantly shortening contact opening time, suppressing jitter inrush current, and reducing the risk of contact sticking in high-voltage scenarios. Diode D1 in the voltage maintenance branch achieves dual-power supply isolation through reverse cutoff, avoiding switching crosstalk. The switching transistor Q2 is compatible with both transistors and MOSFETs, and the filter module supports multiple capacitors in parallel, adapting to the design requirements of different application scenarios, enhancing power supply ripple resistance, and improving circuit reliability and versatility.

[0017] In a preferred embodiment, the switching transistor Q2 is a transistor or a MOSFET.

[0018] In a preferred embodiment, the switching transistor Q2 is an NPN transistor with the first terminal being the collector, the second terminal being the emitter, and the third terminal being the base.

[0019] In a preferred embodiment, the switching transistor Q2 is an N-channel MOSFET with the first terminal being the drain, the second terminal being the source, and the third terminal being the gate.

[0020] In a preferred embodiment, the first filter capacitor C1, the second filter capacitor C2, the third filter capacitor C3, and the fourth filter capacitor C4 are all composed of multiple capacitors connected in parallel.

[0021] In a preferred embodiment, the voltage of the rated power supply VCC1 is higher than the voltage of the holding power supply VCC2.

[0022] In a preferred embodiment, the voltage of the power supply VCC2 is maintained at 40% to 60% of the voltage of the rated power supply VCC1.

[0023] In a preferred embodiment, the rated power supply VCC1 provides rated power to relay K1, and the holding power supply VCC2 provides holding power to relay K1. The holding power supply VCC2 is generally 40% to 60% of the rated power supply VCC1. When relay K1 is in the open or holding state, the holding power supply VCC2 supplies power to relay K1 through diode D1. The second filter capacitor C2 is a supporting filter capacitor, which can be implemented using multiple capacitors connected in parallel. The third filter capacitor C3 is also a supporting filter capacitor, which can also be implemented using multiple capacitors connected in parallel. When relay K1 is in the open state, transistor Q2 is off, and there is no voltage on the relay coil, so the relay does not work. When transistor Q2 is on, the relay coil is energized, and the voltage on the coil is close to the voltage of VCC2. Considering the voltage drop of diode D1, which is generally around 1V, and transistor Q2 being in a saturated conducting state, its voltage drop is negligible. Therefore, the voltage at point B is close to 0V, and the voltage on the relay coil is (VCC2-1)V, which is the holding voltage. Figure 1In this circuit, Q2 can also be replaced by a MOSFET, C4 is a filter capacitor, R4 is a transistor drive resistor, and R3 is a pull-down resistor. To ensure rapid and effective relay engagement when switching from the open to the closed state, a rated voltage needs to be applied to the relay coil. In this circuit, first, the MOSFET Q1 is closed via control signal CH1. At this time, the voltage VCC1 is applied to point A at the upper end of the relay coil. Because VCC1 is higher than VCC2, diode D1 is cut off due to reverse voltage, and the voltage at point A is VCC1. Then, Q2 is turned on via control signal CH2. At this time, the voltage at point B is close to 0V, and the coil is subjected to the voltage VCC1, i.e., the rated voltage, causing the relay to quickly engage. After the relay engagement stabilizes, control signal CH1 disconnects Q1, and the voltage at point A switches to the holding voltage, keeping the relay engaged. A diode and a Zener diode are connected in parallel to the relay coil. When the relay is disconnected, the coil can freewheel through the diode and Zener diode, preventing overvoltage. On the other hand, when the coil power is interrupted, the coil current will bypass and freewheel through this series combination, and the voltage on it will remain equal to the voltage of the Zener diode (plus the forward voltage drop of the diode) until the coil energy is exhausted. During this process, the coil current will decrease rapidly. The electromagnetic force that attracts the coil contacts is strongly correlated with the coil current. Compared to the case of only one diode in parallel, the coil current decreases rapidly, resulting in a faster relay contact opening speed. The fast contact opening speed can greatly reduce the inrush current caused by contact bounce when the relay contacts open, and largely avoid the problem of contact sticking.

[0024] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0025] Furthermore, the terms "upper" and "lower" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "upper" or "lower" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0028] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model are included within the scope of the claims of this utility model pending approval.

Claims

1. A high-voltage relay drive circuit, characterized in that, include: Dual power supply module: includes rated power supply VCC1 and holding power supply VCC2; Relay module: includes relay K1, node A and node B; the first connection terminal of relay K1 is connected to node A, and the second connection terminal of relay K1 is connected to node B; Rated voltage control branch: includes MOSFET Q1, pull-up resistor R1, drive resistor R2 and control terminal CH1; the drain of MOSFET Q1 is connected to the rated power supply VCC1, the gate is connected to the control terminal CH1 through the drive resistor R2, and the source is connected to node A. The gate of MOSFET Q1 is also connected to the rated power supply VCC1 through the pull-up resistor R1. Maintaining voltage isolation branch: includes diode D1, the anode of which is connected to the power supply VCC2 and the cathode is connected to node A; Grounding control branch: includes switch Q2, pull-down resistor R3, drive resistor R4 and control terminal CH2; the first terminal of switch Q2 is connected to node B, the second terminal is grounded, the third terminal is connected to control terminal CH2 through drive resistor R4, and the third terminal is also grounded through pull-down resistor R3; Freewheeling protection branch: includes diode D2 and Zener diode D3, the anode of diode D2 is connected to node B, the cathode is connected to the cathode of Zener diode D3, and the anode of Zener diode D3 is connected to node A; The filtering module includes a first filter capacitor C1, a second filter capacitor C2, a third filter capacitor C3, and a fourth filter capacitor C4. The first filter capacitor C1 is connected in parallel between the rated power supply VCC1 and ground. The second filter capacitor C2 is connected in parallel between the holding power supply VCC2 and ground. The third filter capacitor C3 is connected in parallel between node A and ground. The fourth filter capacitor C4 is connected in parallel between the third terminal of the switching transistor Q2 and ground.

2. The high-voltage relay drive circuit as described in claim 1, characterized in that, The switching transistor Q2 is either a transistor or a MOSFET.

3. The high-voltage relay drive circuit as described in claim 2, characterized in that, The switching transistor Q2 is an NPN transistor with the first terminal being the collector, the second terminal being the emitter, and the third terminal being the base.

4. The high-voltage relay drive circuit as described in claim 2, characterized in that, The switch Q2 is an N-channel MOSFET, with the first terminal being the drain, the second terminal being the source, and the third terminal being the gate.

5. The high-voltage relay drive circuit as described in claim 1, characterized in that, The first filter capacitor C1, the second filter capacitor C2, the third filter capacitor C3, and the fourth filter capacitor C4 are all composed of multiple capacitors connected in parallel.

6. The high-voltage relay drive circuit as described in claim 1, characterized in that, The voltage value of the rated power supply VCC1 is higher than the voltage value of the holding power supply VCC2.

7. The high-voltage relay drive circuit as described in claim 1, characterized in that, The voltage value of the power supply VCC2 is maintained at 40% to 60% of the voltage value of the rated power supply VCC1.

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