A detection circuit with under-voltage protection function

Abstract

The utility model relates to electric control technical field, concretely is a kind of detection circuit with under voltage protection function, including power input and overvoltage protection module, rectification and trigger module, under voltage detection and control module, power supply and voltage stabilizing module and protection action execution module. It can accurately detect under voltage condition, quickly respond and cut off load power supply, with overvoltage protection and voltage stabilizing function simultaneously, can effectively guarantee the safe and stable operation of electrical equipment, solve the existing under voltage protection device slow response, high misjudgment rate, insufficient reliability and other problems. The circuit works through each module cooperation, takes protective measures in time when voltage is abnormal, can restore normal through reset operation after troubleshooting, applicable to a variety of electrical equipment scenes needing voltage protection, improves the safety and stability of power electronic system.

Description

Technical Field

[0001] This utility model relates to the field of electrical control technology, and in particular to a detection circuit with undervoltage protection function. Background Technology

[0002] In the power supply system, voltage fluctuations are affected by various factors such as grid faults and load changes, threatening the stable operation of electrical equipment. When the supply voltage is lower than the range required for normal equipment operation (i.e., undervoltage condition), a series of adverse consequences will occur: for example, motors will operate under voltage, resulting in reduced torque and a sharp increase in current, which can easily lead to overheating and burnout if left untreated for a long time; electronic equipment may become unstable, resulting in data loss or even permanent hardware damage. Currently available undervoltage protection devices generally suffer from slow response speed, making it difficult to cut off power supply in time, exposing equipment to undervoltage risks; they also have a high false alarm rate, and may falsely trigger protection even under normal voltage, affecting continuous equipment operation; and their overall reliability is poor, making protection functions prone to failure in complex voltage fluctuation scenarios.

[0003] To address these pain points, there is an urgent need to develop an undervoltage protection detection circuit that is fast-responding, accurate in judgment, stable and reliable, and also has composite functions such as overvoltage protection and voltage stabilization. This circuit will build a strong voltage anomaly protection barrier for electrical equipment and ensure the safety and efficiency of power application scenarios. Utility Model Content

[0004] The purpose of this invention is to overcome the problems of the prior art and provide a detection circuit with undervoltage protection function to solve the technical problems of slow response speed, high false judgment rate and insufficient reliability of existing undervoltage protection devices. This circuit can accurately detect undervoltage and respond quickly, while also having overvoltage protection and voltage stabilization functions, effectively ensuring the safe and stable operation of electrical equipment.

[0005] The above objectives are achieved through the following technical solutions:

[0006] A detection circuit with undervoltage protection includes a power input and overvoltage protection module, a rectification and triggering module, an undervoltage detection and control module, a power supply and voltage regulation module, and a protection action execution module. The power input and overvoltage protection module is connected between the live wire and the neutral wire to input power and implement overvoltage protection. The rectification and triggering module is connected to the power input and overvoltage protection module to convert AC signals into DC signals and provide trigger signals. The undervoltage detection and control module is connected to the rectification and triggering module to detect the input voltage and output control signals. The power supply and voltage regulation module is connected to both the rectification and triggering module and the undervoltage detection and control module to provide a stable operating power supply. The protection action execution module is connected to the rectification and triggering module to reset the circuit after undervoltage protection is activated.

[0007] Furthermore, the power input and overvoltage protection module includes a metal oxide varistor and a coil; the metal oxide varistor is connected between the live wire and the neutral wire to discharge overvoltage energy; the coil is used to detect current or voltage-related parameters in the circuit.

[0008] Furthermore, the metal oxide varistor is model number 07D561K.

[0009] Furthermore, the rectification and triggering module includes a bridge rectifier circuit, a silicon controlled rectifier (SCR), and a trigger signal adjustment circuit. The bridge rectifier circuit is composed of a first diode, a second diode, a third diode, and a fourth diode. The cathodes of the first diode and the second diode are connected to form the first terminal of the bridge rectifier circuit; the anodes of the second diode and the fourth diode are connected to form the second terminal of the bridge rectifier circuit; the anodes of the fourth diode and the third diode are connected to form the third terminal of the bridge rectifier circuit; and the cathodes of the third diode and the first diode are connected to form the fourth terminal of the bridge rectifier circuit. The trigger signal adjustment circuit is connected to the control electrode of the SCR and is used to adjust the trigger signal of the SCR.

[0010] Furthermore, the model number of the silicon controlled rectifier SCR1 is CR03.

[0011] Furthermore, the trigger signal adjustment circuit consists of a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor. The first resistor, the second resistor, and the third resistor, which are connected in series, are used to divide the voltage to determine the trigger voltage threshold of the control electrode of the thyristor rectifier. The first capacitor and the fourth resistor are used to filter or adjust the timing characteristics of the trigger signal.

[0012] Furthermore, the undervoltage detection and control module includes a voltage detection chip, a filter circuit consisting of a fifth resistor and a second capacitor, and a transistor; the filter circuit is connected to the voltage detection chip and is used to filter the voltage signal input to the voltage detection chip; the transistor is connected to the OUT pin of the voltage detection chip through a sixth resistor and is used to control the operating state of the thyristor rectifier according to the output signal of the voltage detection chip.

[0013] Furthermore, the voltage detection chip is model APX823-26W5G-7; the transistor is model MMBT2222LT1G.

[0014] Furthermore, the power supply and voltage regulation module includes a Zener diode, a seventh resistor, an eighth resistor, a ninth resistor, and a third capacitor; the seventh resistor, the eighth resistor, and the ninth resistor are connected in series to the cathode of the Zener diode, the anode of the Zener diode is grounded, and the third capacitor is connected in parallel across the Zener diode.

[0015] Furthermore, the protection action execution module includes a switch.

[0016] This utility model provides a detection circuit with undervoltage protection. Firstly, through high-precision voltage detection and filtering, it accurately detects the input voltage, effectively reducing the false alarm rate and ensuring accurate and reliable voltage status judgment. Secondly, the circuit design achieves a fast response; upon detecting an undervoltage signal, it quickly cuts off the power supply to the load, resulting in a short response time and timely protection of electrical equipment, preventing damage due to undervoltage. Thirdly, it offers multiple functions, not only providing undervoltage protection but also overvoltage protection. Simultaneously, a voltage regulator circuit provides a stable power supply to internal components, comprehensively ensuring the safe and stable operation of electrical equipment. Furthermore, a convenient reset switch is included for manual circuit reset after fault diagnosis. The overall circuit layout is reasonable, parameters are properly matched, and reliability is high, meeting the requirements for long-term stable operation of electrical equipment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the detection circuit with undervoltage protection function described in this utility model;

[0018] Figure 2 This is a circuit diagram of a detection circuit with undervoltage protection function according to the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the figures and embodiments.

[0020] like Figure 1 As shown, a detection circuit with undervoltage protection function includes a power input and overvoltage protection module, a rectification and triggering module, an undervoltage detection and control module, a power supply and voltage regulation module, and a protection action execution module, wherein:

[0021] The power input and overvoltage protection module is connected between the live wire L and the neutral wire N, and is used to input power and realize overvoltage protection.

[0022] The rectification and triggering module is connected to the power input and overvoltage protection module, and is used to convert AC signals into DC signals and provide trigger signals;

[0023] The undervoltage detection and control module is connected to the rectification and triggering module and is used to detect the input voltage and output a control signal.

[0024] The power supply and voltage regulation module is connected to the rectification and triggering module and the undervoltage detection and control module to provide a stable operating power supply;

[0025] The protection action execution module is connected to the rectification and triggering module and is used to reset the circuit after the undervoltage protection action.

[0026] like Figure 2 As shown, the power input and overvoltage protection module in this embodiment includes a metal oxide varistor (MOV1) and a coil. The MOV1 is connected between the live wire L and the neutral wire N to discharge overvoltage energy. The coil is used to detect current or voltage-related parameters in the circuit, providing electrical signals related to the main circuit to subsequent circuits. The MOV1 is model 07D561K.

[0027] like Figure 2 As shown, the rectification and triggering module in this embodiment includes a bridge rectifier circuit, a silicon controlled rectifier (SCR1), and a trigger signal conditioning circuit, wherein:

[0028] The bridge rectifier circuit consists of a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4, and is used to convert AC signals into DC signals. The cathodes of the first diode D1 and the second diode D2 are connected as the first terminal of the bridge rectifier circuit; the anodes of the second diode D2 and the fourth diode D4 are connected as the second terminal of the bridge rectifier circuit; the anodes of the fourth diode D4 and the third diode D3 are connected as the third terminal of the bridge rectifier circuit; and the cathodes of the third diode D3 and the first diode D1 are connected as the fourth terminal of the bridge rectifier circuit.

[0029] The trigger signal adjustment circuit is connected to the control electrode GP of the silicon controlled rectifier (SCR1) and is used to adjust the trigger signal of the SCR1. The SCR1 is a CR03.

[0030] like Figure 2As shown, the trigger signal adjustment circuit consists of a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first capacitor C1. The first resistor R1, the second resistor R2, and the third resistor R3, which are connected in series, are used to divide the voltage to determine the trigger voltage threshold of the control electrode GP of the silicon controlled rectifier SCR1. The first capacitor C1 and the fourth resistor R4 are used to filter or adjust the timing characteristics of the trigger signal.

[0031] like Figure 2 As shown, the undervoltage detection and control module in this embodiment includes a voltage detection chip U1, a filter circuit composed of a fifth resistor R5 and a second capacitor C2, and a transistor Q1. The DS pin of the voltage detection chip U1 is used to detect the input voltage, and the OUT pin of the voltage detection chip U1 is used to output a signal. The filter circuit is connected to the voltage detection chip U1 and is used to filter the voltage signal input to the voltage detection chip U1. The transistor Q1 is connected to the OUT pin of the voltage detection chip U1 through a sixth resistor R6 and is used to control the operating state of the silicon controlled rectifier SCR1 according to the output signal of the voltage detection chip U1.

[0032] When the input voltage is lower than the threshold set by the voltage detection chip U1, the output signal of the OUT pin of the voltage detection chip U1 changes, which turns on the transistor Q1 through the sixth resistor R6, thereby controlling the working state of the trigger circuit of the silicon controlled rectifier SCR1.

[0033] In this embodiment, the voltage detection chip U1 is model APX823-26W5G-7; the transistor Q1 is model MMBT2222LT1G.

[0034] like Figure 2 As shown, the power supply and voltage regulation module in this embodiment includes a Zener diode Z1, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a third capacitor C3. The seventh resistor R7, the eighth resistor R8, and the ninth resistor R9 are connected in series to the cathode of the Zener diode Z1, and the anode of the Zener diode Z1 is grounded. The third capacitor C3 is connected in parallel across the Zener diode Z1, outputting a stable voltage to the VDD+ pin of the voltage detection chip U1. The Zener diode Z1, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the third capacitor C3 form a voltage regulation circuit to stabilize the input +12V voltage at a preset level, providing a stable power supply for the voltage detection chip U1 and other circuit components. The Zener diode Z1 is a TZM5242B-GS08.

[0035] like Figure 2As shown, the protection action execution module in this embodiment includes a switch S1; S1 is a manual reset switch or an external interface for triggering protection actions, used to reset the circuit after the undervoltage fault is cleared.

[0036] This detection circuit includes a power input and overvoltage protection module, a rectification and triggering module, an undervoltage detection and control module, a power supply and voltage regulation module, and a protection action execution module. The composition and connection relationship of each module are as follows:

[0037] 1. Power input and overvoltage protection module

[0038] A metal oxide varistor MOV1 (model 07D561K) is connected between the live wire L and the neutral wire N. When an overvoltage occurs in the circuit, the resistance of MOV1 decreases rapidly, dissipating the overvoltage energy and preventing damage to subsequent circuit components from excessive voltage. Simultaneously, a coil is provided to detect current or voltage-related parameters in the circuit, providing subsequent circuits with electrical signals relevant to the main circuit.

[0039] 2. Rectification and Triggering Module

[0040] A bridge rectifier circuit composed of four diodes D1-D4 (model M7) converts the AC signal from the power input section into a DC signal, providing a suitable DC operating voltage for subsequent circuits. A silicon controlled rectifier (SCR1, model CR03) is used, and its control gate (GP) trigger signal is adjusted by a circuit consisting of resistors R1-R4 and capacitor C1. R1, R2, and R3 are used for voltage division to determine the control gate trigger voltage threshold; C1 and R4 are used to filter or adjust the timing characteristics of the trigger signal, ensuring that the SCR triggers accurately at the appropriate time.

[0041] 3. Undervoltage detection and control module

[0042] A voltage detection chip U1 (model APX823-26W5G-7) is used, with its DS pin used to detect the input voltage. When the input voltage is lower than the chip's set threshold, the OUT pin outputs a corresponding signal. Resistor R5 and capacitor C2 form a filter circuit to filter the voltage signal input to the U1 chip, removing high-frequency noise and other interference signals, enabling the detection chip to more accurately detect the true value of the input voltage. Transistor Q1 (model MMBT2222LT1G) acts as a signal amplifier or switch. When the U1 chip detects a change in the undervoltage output signal, it controls the conduction or cutoff of transistor Q1 through R6, thereby controlling the working state of the thyristor trigger circuit.

[0043] 4. Power supply and voltage regulation module

[0044] A voltage regulator circuit is formed by using Zener diode Z1 (model TZM5242B-GS08), resistors R7-R9, and capacitor C3 to stabilize the input +12V voltage at a suitable level, providing a stable power supply for circuit components such as chip U1, and ensuring that these components work normally under a stable voltage.

[0045] 5. Protection Action Execution Module

[0046] The setting switch S1 (Trip) can be a manual reset switch or an external interface for triggering protection actions. After an undervoltage protection action occurs, this switch can be operated to reset the circuit and restore it to a normal operating ready state.

[0047] Working principle:

[0048] 1. Normal Operating State: When power is input, MOV1 is in a high-impedance state, which does not affect the normal operation of the circuit. The AC voltage is rectified into DC voltage by the bridge rectifier D1-D4. This DC voltage provides power to the SCR1 and its trigger circuit. Simultaneously, after filtering by R5 and C2, it is input to the DS pin of the U1 chip for voltage detection. Meanwhile, the +12V power supply provides a stable operating power to the U1 chip and other chips through the voltage regulator circuit composed of R7-R9, C3, and Z1. At this time, if the input voltage is within the normal range, the OUT pin of the U1 chip maintains its original state, transistor Q1 is not conducting, the SCR1 is in the off state, and the load operates normally.

[0049] 2. Undervoltage condition: When the input voltage is lower than the undervoltage threshold set by the U1 chip, the output signal of the OUT pin of the U1 chip changes, turning on transistor Q1 through R6. After transistor Q1 turns on, it changes the potential of the control electrode GP of the SCR1, satisfying its trigger condition, and the SCR1 turns on, thereby cutting off the power supply to the load and realizing undervoltage protection.

[0050] 3. Overvoltage condition: If an overvoltage occurs in the circuit, the resistance of MOV1 decreases rapidly to dissipate the overvoltage energy and protect downstream circuit components from excessive voltage surges. Once the overvoltage disappears, MOV1 returns to its high-resistance state.

[0051] 4. Reset process: After the undervoltage fault is cleared, the circuit can be reset by operating switch S1 (Trip) to return it to normal working preparation state and wait for the next test.

[0052] This embodiment combines Figure 2 Further explanation of the connection relationships of this detection circuit, including:

[0053] Power input and overvoltage protection module: MOV1 (model 07D561K) is connected between the live wire L and the neutral wire N, and a coil is connected in series. The coil is used to detect circuit parameters and output electrical signals to the rectification and triggering module.

[0054] Rectification and triggering module: D1-D4 (model M7) form a bridge rectifier circuit. Its input terminal is connected to the power input and the coil of the overvoltage protection module. Its output terminal is connected to the anode of SCR1 (model CR03) and the trigger signal conditioning circuit respectively. The trigger signal conditioning circuit consists of R1-R4 and C1. One end of R1 is connected to the output terminal of the bridge rectifier circuit. The other end is connected to C1 and R4 after being divided by R2 and R3. The other end of C1 and R4 is connected to the control electrode GP of SCR1. R3 is grounded.

[0055] Undervoltage detection and control module: The DS pin of U1 (model APX823-26W5G-7) is connected to the output of the bridge rectifier circuit through the filter circuit composed of R5 and C2. The VDD+ pin is connected to the output of the power supply and voltage regulation module. The OUT pin is connected to the base of Q1 (model MMBT2222LT1G) through R6. The collector of Q1 is connected to the control electrode (GP) of SCR1, and the emitter is grounded.

[0056] Power supply and voltage regulation module: The +12V power input terminal is connected to the cathode of Z1 (model TZM5242B-GS08) through R7, R8 and R9 in series, and the anode of Z1 is grounded; C3 is connected in parallel across Z1, and its two ends output a stable voltage to the VDD+ pin of U1.

[0057] Protection action execution module: S1 (Trip) is connected to the cathode of SCR1 at one end and to the load at the other end. At the same time, the control terminal of S1 is connected to the reset signal source.

[0058] In this embodiment, the parameters of each component are reasonably matched to ensure that the circuit can work stably under normal, undervoltage, and overvoltage conditions, achieving precise protection and rapid response.

[0059] The above description is merely a preferred embodiment of this utility model, but the scope of protection of this utility model is not limited thereto. Any variations or substitutions that can be conceived by those skilled in the art within the scope of the technology disclosed in this utility model are included within the scope of protection of this utility model. Therefore, the scope of protection of this utility model should be determined by the scope of the claims.

Claims

1. A detection circuit with undervoltage protection function, characterized in that, It includes a power input and overvoltage protection module, a rectification and triggering module, an undervoltage detection and control module, a power supply and voltage regulation module, and a protection action execution module; The power input and overvoltage protection module is connected between the live wire (L) and the neutral wire (N) to input power and achieve overvoltage protection; The rectification and triggering module is connected to the power input and overvoltage protection module, and is used to convert AC signals into DC signals and provide trigger signals; The undervoltage detection and control module is connected to the rectification and triggering module and is used to detect the input voltage and output a control signal. The power supply and voltage regulation module is connected to the rectification and triggering module and the undervoltage detection and control module to provide a stable operating power supply; The protection action execution module is connected to the rectification and triggering module and is used to reset the circuit after the undervoltage protection action.

2. The detection circuit with undervoltage protection function according to claim 1, characterized in that, The power input and overvoltage protection module includes a metal oxide varistor (MOV1) and a coil; the metal oxide varistor (MOV1) is connected between the live wire (L) and the neutral wire (N) to discharge overvoltage energy; the coil is used to detect the current or voltage-related parameters in the circuit.

3. A detection circuit with undervoltage protection function according to claim 2, characterized in that, The metal oxide varistor (MOV1) is model number 07D561K.

4. A detection circuit with undervoltage protection function according to claim 2, characterized in that, The rectification and triggering module includes a bridge rectifier circuit, a silicon controlled rectifier (SCR1), and a trigger signal conditioning circuit. The bridge rectifier circuit is composed of a first diode (D1), a second diode (D2), a third diode (D3), and a fourth diode (D4). The cathodes of the first diode (D1) and the second diode (D2) are connected to form the first terminal of the bridge rectifier circuit; the anodes of the second diode (D2) and the fourth diode (D4) are connected to form the second terminal of the bridge rectifier circuit; the anodes of the fourth diode (D4) and the third diode (D3) are connected to form the third terminal of the bridge rectifier circuit; and the cathode of the third diode (D3) and the anode of the first diode (D1) are connected to form the fourth terminal of the bridge rectifier circuit. The trigger signal adjustment circuit is connected to the control electrode of the silicon controlled rectifier (SCR1) and is used to adjust the trigger signal of the silicon controlled rectifier (SCR1).

5. A detection circuit with undervoltage protection function according to claim 4, characterized in that, The model of the silicon controlled rectifier SCR1 is CR03.

6. A detection circuit with undervoltage protection function according to claim 4, characterized in that, The trigger signal adjustment circuit consists of a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), and a first capacitor (C1). The first resistor (R1), the second resistor (R2), and the third resistor (R3), which are connected in series, are used to divide the voltage to determine the trigger voltage threshold of the control electrode of the silicon controlled rectifier (SCR1). The first capacitor (C1) and the fourth resistor (R4) are used to filter or adjust the timing characteristics of the trigger signal.

7. A detection circuit with undervoltage protection function according to claim 4, characterized in that, The undervoltage detection and control module includes a voltage detection chip (U1), a filter circuit consisting of a fifth resistor (R5) and a second capacitor (C2), and a transistor (Q1). The filter circuit is connected to the voltage detection chip (U1) and is used to filter the voltage signal input to the voltage detection chip (U1). The transistor (Q1) is connected to the OUT pin of the voltage detection chip (U1) through a sixth resistor (R6) and is used to control the operating state of the silicon controlled rectifier (SCR1) according to the output signal of the voltage detection chip (U1).

8. A detection circuit with undervoltage protection function according to claim 7, characterized in that, The voltage detection chip (U1) is model APX823-26W5G-7; the transistor (Q1) is model MMBT2222LT1G.

9. A detection circuit with undervoltage protection function according to claim 1, characterized in that, The power supply and voltage regulation module includes a Zener diode (Z1), a seventh resistor (R7), an eighth resistor (R8), a ninth resistor (R9), and a third capacitor (C3). The seventh resistor (R7), the eighth resistor (R8), and the ninth resistor (R9) are connected in series to the cathode of the Zener diode (Z1), the anode of the Zener diode (Z1) is grounded, and the third capacitor (C3) is connected in parallel across the Zener diode (Z1).

10. A detection circuit with undervoltage protection function according to claim 4, characterized in that, The protection action execution module includes a switch (S1).

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