Self-recovery overvoltage and undervoltage protection circuit and protector
By introducing a relay drive circuit with voltage comparison and delay adjustment into the over/under voltage protection circuit, the problems of circuit complexity and high cost in the prior art are solved, and circuit simplification and equipment loss are achieved.
Patent Information
- Application Number
- CN202422877915.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2034-11-25
AI Technical Summary
Existing over- and under-voltage protection circuits are complex and costly, making it difficult to achieve accurate voltage comparison and simplify circuit design.
A relay drive circuit with a voltage comparison unit is adopted, combined with a delay adjustment unit. The relay drive circuit controls the opening or closing of the relay, which simplifies the circuit structure and reduces the number of external components. The QW2201A driver chip is used for accurate voltage judgment and delay control.
This simplifies the circuit structure and reduces costs, while also enabling soft switching of relays through delay adjustment, thus reducing equipment wear.
Smart Images
Figure CN223651960U_ABST
Abstract
Description
Technical Field
[0001] This application generally relates to the technical field of low-voltage electrical appliances, and more specifically, to a self-resetting over / under-voltage protection circuit and protector. Background Technology
[0002] With increasing awareness of safe electricity use, more and more electrical installations are designing and using self-resetting over / under voltage protectors. Prolonged operation of household appliances or industrial equipment under excessively high or low voltage can easily damage the motors of these appliances and equipment, affecting their lifespan. Existing technologies include some over / under voltage protection circuits, such as those using relays and T-junctions. However, the main problems with these existing circuits are their complex structure and high cost. Utility Model Content
[0003] A primary objective of this application is to provide a relay drive circuit that can accurately compare voltages and control the operation of the relay based on the judgment result and / or a set time. This simplifies the structure of the over / under voltage protection circuit, reduces external components, thereby lowering costs and at least partially overcoming one or more problems caused by limitations and defects in related technologies.
[0004] To achieve the above-mentioned objectives, this application adopts the following technical solution:
[0005] According to one aspect of this application, a self-resetting over / under voltage protection circuit is provided, comprising a power supply circuit, a detection circuit, a relay, and a relay drive circuit; the relay is disposed in the input power grid and is used to control the electrical connection or disconnection between the input power grid and the load; the power supply circuit is connected to the input power grid and is used to supply power to subsequent circuits; the input terminal of the detection circuit is connected to the input power grid and is used to collect voltage signals and feed them back to the relay drive circuit; the output terminal of the relay drive circuit is connected to the relay; the relay drive circuit is provided with a voltage comparison unit; the relay drive circuit determines whether the voltage signal is over-voltage or under-voltage based on a set threshold; the relay drive circuit generates a control signal to the relay according to the determination result and / or a preset delay adjustment signal to control the relay to open or close.
[0006] According to one embodiment of this application, the relay driving circuit is provided with a delay adjustment unit. The delay adjustment unit is set to a preset time. After the relay driving unit returns to normal, when the relay driving circuit determines that it is within the preset time, the relay driving circuit is configured to control the relay to close.
[0007] According to one embodiment of this application, the relay driving circuit includes a driving chip, wherein the driving chip is selected as QW2201A, the input terminal of the driving chip is respectively connected to the power supply circuit and the detection circuit, and the output terminal of the driving chip is respectively connected to the two poles of the relay.
[0008] According to one embodiment of this application, the detection circuit includes a first detection and a second detection. The first detection obtains a voltage signal from the input terminal of the relay, and the second detection obtains a voltage signal from the output terminal of the relay. The first detection and the second detection are respectively connected to the detection pins of the driver chip.
[0009] According to one embodiment of this application, the first detection includes a plurality of resistors connected in series for voltage division, and the second detection includes a plurality of resistors connected in series for voltage division.
[0010] According to one embodiment of this application, the power supply circuit includes a resistor-capacitor step-down circuit and a rectifier circuit connected in series. The resistor-capacitor step-down circuit is used to reduce the voltage and output a stable voltage.
[0011] According to one embodiment of this application, the RC step-down circuit includes a resistor and a capacitor connected in parallel.
[0012] According to one embodiment of this application, the rectifier circuit includes a bridge rectifier circuit, an electrolytic capacitor, and a ceramic capacitor connected in parallel.
[0013] According to one embodiment of this application, the protection circuit further includes an indicator light circuit, which includes a plurality of working status indicator lights. The plurality of working status indicator lights are connected to the relay drive circuit, and the working status indicator lights switch on / off states in response to the control signal of the relay drive circuit.
[0014] According to another aspect of this application, a self-resetting over / under voltage protector is provided, including the self-resetting over / under voltage protection circuit described above.
[0015] In this application, by employing a relay drive circuit with a voltage comparison unit, the relay can be controlled to open or close according to the judgment structure and / or a preset delay adjustment signal, thus simplifying the structure of the self-resetting over / under voltage circuit.
[0016] In addition, after the grid voltage returns to normal, the relay drive circuit starts the delay adjustment unit. During the start-up period of the delay adjustment unit, the relay drive circuit controls the relay to close, thereby realizing soft switching of the relay and reducing equipment losses.
[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0018] The above and other features and advantages of this application will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.
[0019] Figure 1 This is a schematic diagram of a self-resetting over / under voltage protection circuit according to an exemplary embodiment;
[0020] Figure 2 This is a schematic diagram of a self-resetting over / under voltage protection circuit according to an exemplary embodiment.
[0021] The reference numerals in the attached figures are explained as follows:
[0022] X, input power grid; K1, relay; 1, power supply circuit; 2, detection circuit; 3, relay drive circuit; 4, indicator light circuit. Detailed Implementation
[0023] 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 embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.
[0024] See Figure 1 In one embodiment, the self-resetting over / under voltage protection circuit includes a power supply circuit 1, a detection circuit 2, a relay, and a relay drive circuit 3. The over / under voltage protection circuit is embedded in the mains circuit to protect the circuit when the input voltage of the mains circuit is over-voltage or under-voltage.
[0025] A relay is installed in the input power grid X to control the electrical connection or disconnection between the input power grid X and the load. Power supply circuit 1 is connected to the input power grid X and is used to supply power to the subsequent circuits. The input terminal of detection circuit 2 is connected to the input power grid X. Detection circuit 2 is used to collect voltage signals and feed them back to relay drive circuit 3. The output terminal of relay drive circuit 3 is connected to the relay. Relay drive circuit 3 is equipped with a voltage comparison unit. Relay drive circuit 3 judges whether the voltage signal is over-voltage or under-voltage based on a set threshold. Relay drive circuit 3 generates a control signal to the relay according to the judgment result and / or a preset delay adjustment signal to control the relay to open or close.
[0026] See Figure 2 In one embodiment, relay K1 is located on the live wire of the input power grid X.
[0027] In one embodiment, the power supply circuit 1 includes a resistor-capacitor (RC) step-down circuit 11 and a rectifier circuit 12 connected in series. The RC step-down circuit 11 is used to reduce the voltage and output a stable voltage. The RC step-down circuit 11 includes a resistor R2 and a capacitor C1 connected in parallel. The capacitive reactance generated by R2 and C1 at the power frequency AC signal limits the current, providing a stable operating voltage for subsequent circuits such as the relay drive circuit 3 and the indicator light circuit 4. The rectifier circuit 12 includes a bridge rectifier circuit 12D1-D4 connected in parallel, an electrolytic capacitor EC1, and a ceramic capacitor C2. The bridge rectifier circuit 12D1-D4 can be used to convert AC to DC. The electrolytic capacitor EC1 and the ceramic capacitor C2 filter out the AC component in the DC, thereby achieving a filtering effect and obtaining a more stable voltage.
[0028] See Figure 2 In one embodiment, the detection circuit 2 includes a first detection and a second detection. The first detection obtains a voltage signal from the input terminal of the relay, and the second detection obtains a voltage signal from the output terminal of the relay K1. The first and second detections are respectively connected to the detection pins of the driver chip. In this embodiment, by setting the first and second detections at the input and output terminals of the relay K1 respectively, the voltage withstand limit of the resistor is overcome, and the safety performance of the circuit is improved. In a specific embodiment, the first detection includes multiple series voltage divider resistors R3, R4, and R5. The input terminal of resistor R3 is connected to the input terminal of the relay K1, the output terminal of resistor R4 is connected to the relay driver circuit 3, and the output terminal of resistor R5 is grounded. The second detection includes multiple series voltage divider resistors R10, R11, R12, and R13. The input terminal of resistor R10 is connected to the output terminal of the relay K1, the output terminal of resistor R12 is connected to the relay driver circuit 3, and the output terminal of resistor R13 is grounded.
[0029] See Figure 2 In one embodiment, the relay drive circuit 3 is provided with a delay adjustment unit. The delay adjustment unit is set to a preset time. After the relay drive unit returns to normal, when the relay drive circuit 3 determines that it is within the preset time, the relay drive circuit 3 is configured to control the relay to close.
[0030] In this embodiment, the relay driving circuit 3 includes a driving chip U1, preferably a QW2201A. The driving chip U1 includes pins OUTN, OUTP, VIN, VIS, and VOS. Pin VIN is connected to the power supply circuit 1. Pins OUTN and OUTP are connected to the positive and negative terminals of the relay, respectively. Pins VIS and VOS are connected to the first and second sensors, respectively. When the input grid voltage X is too high or too low, the voltage input to the driving chip U1 from the first and second sensors will also increase or decrease accordingly. At this time, the voltage on the VIS and VOS pins exceeds or falls below the threshold voltage range set internally by the driving chip U1. The driving chip U1 determines that the grid is in an overvoltage or undervoltage state, and outputs pulses from pins OUTN and / or OUTP, causing the relay K1 to open.
[0031] Subsequently, the driver chip U1 continues to monitor the input power grid X, and activates the delay adjustment unit when the input power grid XVIN approaches 0. After detecting that the voltage of the input power grid X has returned to normal, and if the driver chip U1 determines that it is still within a preset time, the driver chip U1 outputs a pulse to the relay K1 to control the relay K1 to close. By utilizing delay adjustment, the relay K1 is switched when the AC signal voltage approaches 0, achieving soft switching of the relay K1 and reducing equipment losses.
[0032] See Figure 2 The protection circuit also includes an indicator light circuit 4, which includes several working status indicator lights. These indicator lights are connected to the relay drive circuit 3, and their on / off states switch in response to the control signal from the relay drive circuit 3. In a specific embodiment, the indicator light circuit 4 includes a safety indicator light LED1, a warning indicator light LED2, and several resistors disposed on the periphery. The driver chip U1 has pins LED-safety and LED-warning, which are connected to the safety indicator light LED1 and the warning indicator light LED2, respectively.
[0033] In another embodiment, a self-resetting over / under voltage protector includes the self-resetting over / under voltage protection circuit described above.
[0034] In the embodiments of this application, the terms "fitting," "connection," and other such terms should be interpreted broadly. For example, "connection" can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.
[0035] The above are merely preferred embodiments of the application examples and are not intended to limit the application examples. For those skilled in the art, the application examples can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the application examples should be included within the protection scope of the application examples.
Claims
1. A self-resetting over / under voltage protection circuit, characterized in that, The system includes a power supply circuit, a detection circuit, a relay, and a relay drive circuit. The relay is located in the input power grid and is used to control the electrical connection or disconnection between the input power grid and the load. The power supply circuit is connected to the input power grid and is used to supply power to subsequent circuits. The input terminal of the detection circuit is connected to the input power grid and is used to collect voltage signals and feed them back to the relay drive circuit. The output terminal of the relay drive circuit is connected to the relay. The relay drive circuit has a voltage comparison unit. The relay drive circuit determines whether the voltage signal is over-voltage or under-voltage based on a set threshold. The relay drive circuit generates a control signal to the relay according to the determination result and / or a preset delay adjustment signal to control the relay to open or close.
2. The self-resetting over / under voltage protection circuit as described in claim 1, characterized in that, The relay drive circuit is equipped with a delay adjustment unit. The delay adjustment unit is set to a preset time. After the relay drive unit returns to normal, when the relay drive circuit determines that it is within the preset time, the relay drive circuit is configured to control the relay to close.
3. The self-resetting over / under voltage protection circuit as described in claim 1, characterized in that, The relay driving circuit includes a driving chip, which is a QW2201A. The input terminals of the driving chip are connected to the power supply circuit and the detection circuit, respectively, and the output terminals of the driving chip are connected to the two poles of the relay.
4. The self-resetting over / under voltage protection circuit as described in claim 3, characterized in that, The detection circuit includes a first detection and a second detection. The first detection obtains a voltage signal from the input terminal of the relay, and the second detection obtains a voltage signal from the output terminal of the relay. The first detection and the second detection are respectively connected to the detection pins of the driver chip.
5. The self-resetting over / under voltage protection circuit as described in claim 4, characterized in that, The first detection includes multiple resistors connected in series for voltage division, and the second detection includes multiple resistors connected in series for voltage division.
6. The self-resetting over / under voltage protection circuit as described in claim 1, characterized in that, The power supply circuit includes a resistor-capacitor step-down circuit and a rectifier circuit connected in series. The resistor-capacitor step-down circuit is used to reduce the voltage and output a stable voltage.
7. The self-resetting over / under voltage protection circuit as described in claim 6, characterized in that, The RC step-down circuit includes resistors and capacitors connected in parallel.
8. The self-resetting over / under voltage protection circuit as described in claim 6, characterized in that, The rectifier circuit includes a bridge rectifier circuit, an electrolytic capacitor, and a ceramic capacitor connected in parallel.
9. The self-resetting over / under voltage protection circuit as described in claim 1, characterized in that, The protection circuit also includes an indicator light circuit, which includes several working status indicator lights. These several working status indicator lights are connected to the relay drive circuit, and the working status indicator lights switch on and off in response to the control signal of the relay drive circuit.
10. A self-resetting over / under voltage protector, characterized in that, Includes the self-resetting over / under voltage protection circuit as described in any one of claims 1 to 9.