A universal protection circuit

Abstract

The embodiment of the present invention relates to a universal protection circuit, including an electric control device, a first resistor, a second resistor, a first diode, a second diode, a voltage regulator, a first electrolytic capacitor, an optocoupler, a power input terminal and an output terminal, wherein the output terminal is used to connect to a load. When the load has abnormalities such as voltage, current, working timeout, leakage, etc. during use, the resistance of the second resistor can be reduced by the optocoupler, and the current of the DC circuit can be increased, so that the voltage flowing through the coil of the electric control device reaches the driving voltage, and the electric control device starts to cut off the power supply to the load, so that the entire load is in a power-off state, effectively preventing the safety hazards caused by the load abnormality. The universal protection circuit can only automatically recover after unplugging the load electrical plug or completely cutting off the load power supply, thereby improving its safety. It solves the technical problem that the power supply is not cut off when the existing electrical equipment or electrical appliances are abnormal, and the safety hazards caused by the electrical equipment or electrical appliances during the abnormal process are handled.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical appliance protection circuits, and in particular to a universal protection circuit. Background Art

[0002] In view of the unstable factors in the power circuit of existing electrical equipment or electrical appliances, the circuit designed to prevent such unstable factors from affecting the circuit effect is called a protection circuit. Existing protection circuits include overcurrent protection, overvoltage protection, overheating protection, no-load protection, short circuit protection and other protection circuits.

[0003] The reset in the protection circuit is divided into automatic (active) reset and manual (passive) reset. Most of the passive reset protection circuits have a reset switch, and the structure is basically a mechanical structure. However, most of the passive reset protection circuits on the market often have automatic reset anomalies. For example, the current protection switch has a structure that there is a double layer or several layers of metal sheets with different thermal expansion coefficients inside the switch. When the current passing through the metal sheet is too large, the metal sheet will instantly heat up, expand and deform, triggering the contacts to disconnect and protect the rear part of the circuit from power failure. However, since the metal sheet is a physical structure, there is a risk of automatic reset when the temperature drops. This poses a certain safety hazard to the protected electrical equipment or appliances if you forget to unplug the plug to cut off the power supply, and to repair or troubleshoot the electrical equipment or appliances.

[0004] Therefore, in response to the above situation, how to automatically cut off the main power supply of the electrical equipment or appliances when abnormalities such as voltage, current, working timeout, leakage, etc. occur during use, so as to put the entire appliance in a power-off state and prevent the safety hazards caused by the abnormalities of the electrical equipment or appliances has become an important technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0005] The embodiment of the present invention provides a universal protection circuit for solving the technical problem that the power supply of existing electrical equipment or electrical appliances is not cut off when an abnormality occurs, and the potential safety hazard caused by the electrical equipment or electrical appliances during the abnormality processing.

[0006] In order to achieve the above purpose, the embodiment of the present invention provides the following technical solutions:

[0007] A universal protection circuit is applied to electrical equipment or electrical appliances, comprising a DC circuit, an electrical control device, a second resistor, a voltage regulator, a first electrolytic capacitor, an optocoupler device, a power input terminal and an output terminal, wherein the DC circuit comprises a first resistor, a first diode and a second diode;

[0008] The first end of the electric control device is connected to the first end of the power input end, the second end of the electric control device is connected to the output end, the voltage regulator and the first electrolytic capacitor are respectively connected in parallel to the third end and the fourth end of the electric control device, the third end of the electric control device is also connected to the cathode of the first diode, the anode of the first diode is connected in series with the first resistor and is connected to the first end of the power input end, the second end of the power input end is respectively connected to the anode of the second diode and the first end of the second resistor, the cathode of the second diode is connected to the anode of the first electrolytic capacitor, the second end of the second resistor is connected to the cathode of the first electrolytic capacitor, and the first end of the optocoupler device is connected in parallel to the second resistor;

[0009] Wherein, the output end is used to be connected to a load.

[0010] Preferably, the electrical control device is a relay.

[0011] Preferably, the universal protection circuit also includes a current detection circuit and a varistor; the second end of the optocoupler device is connected to the current detection circuit, the input end of the current detection circuit is connected to the output end, the output end of the current detection circuit is connected in series with the load and the second end of the power supply input end, and the varistor is connected in parallel with the power supply input end.

[0012] Preferably, the current detection circuit includes a transformer, a fourth diode connected in parallel with the transformer secondary winding, a second electrolytic capacitor and a fifth resistor, the cathode of the fourth diode is connected to the anode of the third diode, and the cathode of the third diode is connected to the anode of the second electrolytic capacitor.

[0013] Preferably, the universal protection circuit further comprises a timeout protection circuit, and the timeout protection circuit is respectively connected to the output end, the second end of the power input end and the second end of the optocoupler device.

[0014] Preferably, the timeout protection circuit includes a microcontroller unit and a bridge rectifier connected to the microcontroller unit, the microcontroller unit is also connected to the second end of the optocoupler device, and the input end of the bridge rectifier is respectively connected to the output end and the second end of the power input end.

[0015] Preferably, the universal protection circuit further includes a leakage protection circuit, and the leakage protection circuit is respectively connected to the output end, the second end of the power input end and the second end of the optocoupler device.

[0016] Preferably, the leakage protection circuit includes a leakage coil, a bridge rectifier, a leakage chip and a transistor. The second end of the power input end passes through the leakage coil and is respectively connected to the first end of the bridge rectifier and the first end of the load, the output end passes through the leakage coil and is respectively connected to the second end of the bridge rectifier and the second end of the load, the third end of the bridge rectifier is connected to the power supply end of the leakage chip, the control end of the leakage chip is connected to the base of the transistor, the collector of the transistor is connected to the second end of the optocoupler device, and the fourth end of the bridge rectifier and the emitter of the transistor are both grounded.

[0017] The present invention also provides a universal protection circuit, which is applied to electrical equipment or electrical appliances, and includes a DC circuit, an electrical control device, a second resistor, a voltage regulator, a first electrolytic capacitor, a power input terminal and an output terminal, wherein the DC circuit includes a first resistor, a first diode and a second diode;

[0018] The first end of the electric control device is connected to the first end of the power input end, the second end of the electric control device is connected to the output end, the voltage regulator and the first electrolytic capacitor are respectively connected in parallel to the third end and the fourth end of the electric control device, the third end of the electric control device is also connected to the cathode of the first diode, the anode of the first diode is connected in series with the first resistor and is connected to the first end of the power input end, the second end of the power input end is respectively connected to the anode of the second diode and the first end of the second resistor, the cathode of the second diode is connected to the anode of the first electrolytic capacitor, and the second end of the second resistor is connected to the cathode of the first electrolytic capacitor;

[0019] Wherein, the output end is used to be connected to a load.

[0020] Preferably, the electrical control device is a relay.

[0021] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0022] 1. The universal protection circuit is composed of an electric control device, a first resistor, a second resistor, a first diode, a second diode, a voltage regulator, a first electrolytic capacitor, an optocoupler, a power input terminal and an output terminal. The output terminal is used to connect to a load. The voltage of the second resistor is adjusted by the optocoupler to control the current of the DC circuit, thereby controlling the voltage flowing through the coil of the electric control device to turn on or off the electric control device, so as to cut off the power supply to the load. When the load has abnormalities such as voltage, current, working timeout, leakage, etc. during use, the resistance of the second resistor can be reduced by the optocoupler, and the current of the DC circuit can be increased, so that the voltage flowing through the coil of the electric control device reaches the driving voltage, and the coil of the electric control device is driven to start cutting off the power supply to the load, so that the entire load is in a power-off state, effectively preventing the safety hazards caused by the load abnormality. The universal protection circuit also has a passive reset function. When the universal protection circuit is triggered, the live or neutral line of the load's main power supply must be disconnected before the entire universal protection circuit can be restored. This can effectively prevent the potential safety hazards caused by the automatic reset of other types of protection electronic devices when the load is abnormal and forgetting to unplug the power supply to handle the abnormality. This solves the technical problem that the existing electrical equipment or electrical appliances do not cut off the power supply when the load is abnormal, and the potential safety hazards caused by the electrical equipment or electrical appliances during the abnormality handling process;

[0023] 2. Compared with the existing current protection circuit, this universal protection circuit can automatically recover only after the load electrical plug is unplugged or the load power supply is completely cut off, thereby improving its safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 This is a circuit diagram of Embodiment 1 of the universal protection circuit described in an embodiment of the present invention.

[0026] Figure 2 This is a circuit diagram of Embodiment 2 of the universal protection circuit described in an embodiment of the present invention.

[0027] Figure 3 This is a circuit diagram of Embodiment 3 of the universal protection circuit described in an embodiment of the present invention.

[0028] Figure 4 This is a circuit diagram of Embodiment 4 of the universal protection circuit described in an embodiment of the present invention.

[0029] Figure 5This is a circuit diagram of Embodiment 5 of the universal protection circuit described in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The embodiment of the present application provides a universal protection circuit for solving the technical problem that the power supply of existing electrical equipment or electrical appliances is not cut off when an abnormality occurs, and the potential safety hazard caused by the electrical equipment or electrical appliances during the abnormality processing.

[0032] Embodiment 1:

[0033] The embodiment of the present invention provides a universal protection circuit, which is applied to electrical equipment or electrical appliances, mainly used in household appliances such as refrigerators, televisions, air conditioners, etc. Figure 1 As shown, Figure 1 This is a circuit diagram of Embodiment 1 of the universal protection circuit described in an embodiment of the present invention.

[0034] The embodiment of the present invention provides a universal protection circuit, including a DC circuit, an electric control device RLY, a second resistor R2, a voltage regulator ZD1, a first electrolytic capacitor C1, an optocoupler device U1, a power input terminal and an output terminal OUT-L, and the DC circuit includes a first resistor R1, a first diode D1 and a second diode D2;

[0035] A first end of the electric control device RLY is connected to the first end IN-L of the power input end, a second end of the electric control device RLY is connected to the output end OUT-L, a voltage regulator tube ZD1 and a first electrolytic capacitor C1 are respectively connected in parallel to the third end and the fourth end of the electric control device RLY, the third end of the electric control device RLY is also connected to the cathode of the first diode D1, the anode of the first diode D1 is connected in series with the first resistor R1 and the first end IN-L of the power input end, a second end N of the power input end is respectively connected to the anode of the second diode D2 and the first end of the second resistor R2, a cathode of the second diode D2 is connected to the anode of the first electrolytic capacitor C1, a second end of the second resistor R2 is connected to the cathode of the first electrolytic capacitor C1, and a first end of the optocoupler device U1 is connected in parallel to the second resistor R2.

[0036] It should be noted that the electric control device RLY can be a normally closed relay, or other electric control devices with the same working principle as the relay. The second end N of the power input terminal is the neutral line of the power supply, and the first end IN-L of the power input terminal and the output end OUT-L are the live wires of the power supply. The output end OUT-L is connected to the load. The second end of the optocoupler device U1 is the 1 and 2 pins of the optocoupler device U1, and the first end of the optocoupler device U1 is the 4 and 6 pins of the optocoupler device U1.

[0037] The universal protection circuit of the embodiment of the present invention has few electronic components and is applicable to any type of circuit protection. Different types of protection only need to change their front-end trigger signals. The universal protection circuit can be set on a circuit board, or the universal protection circuit can be set in a circuit board such as a power supply or controller of an electrical appliance.

[0038] The optocoupler device U1 in the embodiment of the present invention is also connected to a controller, and the controller is used to trigger the operation of the optocoupler device U1. The controller may be a single chip microcomputer or a circuit capable of starting the operation of the optocoupler device U1.

[0039] The working principle of the universal protection circuit of the first embodiment of the present invention is: the electric control device RLY is preferentially connected in series in the live wire of the power supply, the first end of the electric control device RLY is connected to the first end IN-L of the power supply input end, and the second end of the electric control device RLY is connected to the output end OUT-L, and the output end OUT-L is connected to the load. During normal operation, the contacts of the electric control device RLY are energized, the first end IN-L of the power supply input end and the output end OUT-L are connected, and when the protection is triggered, the coil of the electric control device RLY is started to disconnect the contacts of the electric control device RLY through the internal mechanical structure, thereby cutting off the live wire power supply of the electrical appliance. The loop in the entire universal protection circuit keeps the contacts of the electric control device RLY in the disconnected state, and can only be restored when the entire universal protection circuit is completely powered off.

[0040] The first end of the first resistor R1 is connected to the first end IN-L of the power input end, the second end of the first resistor R1 is connected to the anode of the first diode D1, the anode of the second diode D2 is connected to the second end N of the power input end, and the cathode of the second diode D2 is connected to the cathode of the first diode D1, forming a simple resistor voltage reduction and rectification into a DC voltage and forming a DC circuit. The second resistor R2 is connected in series to the negative end of the DC circuit to play a current limiting role. The DC circuit and the 4 and 6 pins of the optocoupler device U1 are connected in parallel. The voltage regulator ZD1 and the first electrolytic capacitor C1 are connected in parallel to the two ends of the coil of the electric control device RLY, and these two ends are respectively the positive and negative poles of the DC circuit after the second resistor R2 reduces the voltage. The first electrolytic capacitor C1 has the function of filtering and storing electric energy, which can stabilize the voltage of the coil of the electric control device RLY. The voltage regulator ZD1 can control the voltage of the coil of the electric control device RLY within a safe range to prevent the voltage of the coil in the electric control device RLY from being too high and damaged. It should be noted that the DC circuit is mainly used to provide driving power for the coil of the electric control device RLY.

[0041] When the universal protection circuit is not triggered, the voltage across the electric control device RLY or the current passing through it can only maintain the state of the relay, and cannot trigger the electric control device RLY to work. When the load is in an abnormal state such as voltage, current, timeout, or leakage, the controller connected to the 1 and 2 pins of the optocoupler device U1 can be used to light up the internal photodiode and trigger the 4 and 6 pins of the optocoupler device U1 to turn on. At this time, the resistance across the second resistor R2 decreases, causing the current in the DC circuit to increase. The voltage across the coil of the electric control device RLY meets its driving voltage, and the coil of the electric control device RLY starts to disconnect the contacts of the electric control device RLY through the internal mechanical structure, cutting off the live wire power supply of the load.

[0042] Since the circuit connected to the load is open, the load is in a power-off state, the voltage at pins 1 and 2 of the optocoupler device U1 disappears (that is, there is no voltage), and pins 4 and 6 of the optocoupler device U1 form a high-impedance state. The universal protection circuit continues to form a DC loop through the second resistor R2, and the voltage and current of the entire DC loop continue to maintain the RLY coil of the electrical control device in a working state, and the RLY contacts of the electrical control device remain disconnected.

[0043] It should be noted that the universal protection circuit appropriately adjusts the specifications of the first resistor R1, the second resistor R2 and the voltage regulator ZD1 through the coil parameters of the electric control device RLY, so that the circuit has the voltage or current to trigger and maintain the coil of the electric control device RLY.

[0044] The present invention provides a universal protection circuit through an electric control device, a first resistor, a second resistor, a first diode, a second diode, a voltage regulator, a first electrolytic capacitor, an optocoupler, a power input terminal and an output terminal, the output terminal is used to connect to a load, and the voltage of the second resistor is adjusted by the optocoupler to control the current of the DC circuit, thereby controlling the voltage flowing through the coil of the electric control device to turn on or off the electric control device, so as to cut off the power supply to the load. When the load has abnormalities such as voltage, current, working timeout, leakage, etc. during use, the resistance of the second resistor can be reduced by the optocoupler, and the current of the DC circuit can be increased, so that the voltage flowing through the coil of the electric control device reaches the driving voltage, and the coil of the electric control device is driven to start cutting off the power supply to the load, so that the entire load is in a power-off state, effectively preventing the safety hazards caused by the load abnormality. The universal protection circuit also has a passive reset function. When the universal protection circuit is triggered, the live or neutral line of the load's main power supply must be disconnected before the entire universal protection circuit can be restored. This can effectively prevent the safety hazards caused by the automatic resetting of other types of protection electronic devices when the load is abnormal and forgetting to unplug the power supply to deal with the abnormality. This solves the technical problem of safety hazards caused by the existing electrical equipment or electrical appliances not cutting off the power supply when the load is abnormal and the electrical equipment or electrical appliances being dealt with during the abnormality.

[0045] Embodiment 2:

[0046] Figure 2 This is a circuit diagram of Embodiment 2 of the universal protection circuit described in an embodiment of the present invention.

[0047] Embodiment 2 is based on the universal protection circuit provided in embodiment 1, and adds a current detection circuit and a varistor VDR. The load in the universal protection circuit of the embodiment of the present invention is an electric product, and the universal protection circuit of the embodiment of the present invention mainly plays the role of current protection in the load. The existing load circuit mainly adopts three methods, namely, current fuse, PTC mechanical current fuse and PPTC thermistor, to play the role of current protection. Electric products often have motor stalling during use. The use of traditional current fuses is prone to cause the fuse tube to explode. The load must be sent for repair before it can continue to be used, which will cause a lot of inconvenience to the user experience; electric products often have motor stalling during use. The use of PTC mechanical current fuse has certain self-reset risks if the plug is forgotten to be unplugged during the abnormality handling process due to its mechanical structural defects, which poses a hidden danger to the user's safety; electric products often have motor stalling during use. The use of PPTC thermistor will not have the above two problems, but its working mode is physical change. After protection, there will still be weak current in the entire circuit loop, rather than isolation protection.

[0048] The universal protection circuit of the embodiment of the present invention also includes a current detection circuit and a varistor VDR; the second end of the optocoupler device U1 is connected to the current detection circuit, the input end of the current detection circuit is connected to the output end OUT-L, the output end of the current detection circuit is connected in series with the load and the second end N of the power input end, and the varistor VDR is connected in parallel with the power input end. The current detection circuit includes a transformer CT1, a fourth diode D4 connected in parallel with the secondary winding of the transformer CT1, a second electrolytic capacitor C2 and a fifth resistor R5, the cathode of the fourth diode D4 is connected to the anode of the third diode D3, and the cathode of the third diode D3 is connected to the anode of the second electrolytic capacitor C2.

[0049] It should be noted that the transformer CT1 can be a T-type transformer or a ring-type transformer (passing through the transformer coil). The two ends of the fifth resistor R5 are connected to the optocoupler U1. The second end of the optocoupler U1 is the pins 1 and 2 of the optocoupler U1, and the first end of the optocoupler U1 is the pins 4 and 6 of the optocoupler U1.

[0050] The working principle of the universal protection circuit of the second embodiment of the present invention is:

[0051] The output terminal OUT-L is connected to the load after passing through the electric control device RLY of the universal protection circuit and then connected to the transformer CT1. When the load is working, the working current of the load flows through the transformer CT1, and the transformer CT1 converts the current flowing through the transformer CT1 into voltage according to the principle of electromagnetic induction, and then rectifies it into direct current through the third diode D3 and the fourth diode D4, and filters it through the second electrolytic capacitor C2.

[0052] When the current of the load is too high, the voltage converted by the current detection circuit also increases. At this time, the voltage of the current in the current detection circuit drives the optocoupler device U1, so that its internal photodiode lights up and triggers the optocoupler device U1 to turn on. At this time, the resistance at both ends of the second resistor R2 decreases, and the current in the entire DC circuit increases. The voltage at both ends of the coil of the electrical control device RLY meets its driving voltage. The coil of the electrical control device RLY starts to disconnect the contacts of the electrical control device RLY through the internal mechanical structure, cutting off the connection between the load and the output terminal OUT-L. The entire load is in a power-free state, the voltage of the current detection circuit disappears, and the voltage between the 1 and 2 pins of the optocoupler device U1 also disappears. The 4 and 6 pins of the optocoupler device U1 form a high-impedance state. The universal protection circuit continues to form a loop through the second resistor R2. The voltage and current of the entire loop continue to maintain the coil of the electrical control device RLY in a working state, and the contacts of the electrical control device RLY remain disconnected, so that the circuit in the load and the electronic components of the universal protection circuit will not be damaged by the increase in load, and the safety of the use environment is improved. Compared with the existing current protection circuit, this universal protection circuit can automatically recover only after the load electrical plug is unplugged or the load power supply is completely cut off, thereby improving its safety.

[0053] Embodiment three:

[0054] Figure 3 This is a circuit diagram of Embodiment 3 of the universal protection circuit described in an embodiment of the present invention.

[0055] Embodiment 3 adds a timeout protection circuit based on the universal protection circuit provided in Embodiment 1. The load in the universal protection circuit of the embodiment of the present invention is mainly electric heating, such as toasters, electric kettles, etc. The universal protection circuit of the embodiment of the present invention mainly plays the role of timeout protection in the load. Most of the existing load protection circuits do not have a timeout protection circuit. When the circuit components of the load are abnormal or due to external abnormal conditions, the load may be in a state of continuous working. The heating of the electronic components in the load for a long time may cause a fire hazard.

[0056] Therefore, the universal protection circuit of the embodiment of the present invention also includes a timeout protection circuit, which is respectively connected to the output terminal OUT-L, the second terminal N of the power input terminal and the second terminal of the optocoupler device U1; the timeout protection circuit includes a microcontroller unit MCU and a bridge rectifier bridge connected to the microcontroller unit MCU, the microcontroller unit is also connected to the second terminal of the optocoupler device, and the input terminal of the bridge rectifier bridge is respectively connected to the second terminal of the output terminal and the power input terminal.

[0057] It should be noted that the second end of the optocoupler device U1 is the pins 1 and 2 of the optocoupler device U1, and the first end of the optocoupler device U1 is the pins 4 and 6 of the optocoupler device U1. The timeout protection circuit can be a microcontroller unit MCU, or a clock circuit. When the load working time reaches the maximum limit, the microcontroller unit MCU or the separate clock circuit in the load circuit triggers the second end of the optocoupler device U1 in the universal protection circuit, so that its internal photodiode lights up, and triggers the first end of the optocoupler device U1 in the universal protection circuit to turn on. At this time, the resistance at both ends of the second resistor R2 decreases, and the current of the entire DC circuit increases. The voltage across the coil of the electric control device RLY meets its driving voltage. When the coil of the electric control device RLY is started, the contacts of the electric control device RLY are disconnected through the internal mechanical structure, and the connection between the load and the output terminal OUT-L is cut off. The entire load is in a power-free state, the voltage of the current detection circuit disappears, and the voltage between the second ends of the optocoupler device U1 also disappears. The first end of the optocoupler device U1 forms a high-resistance state, and the universal protection circuit continues to form a loop through the second resistor R2. The voltage and current of the entire loop continue to maintain the coil of the electric control device RLY in a working state, and the contacts of the electric control device RLY remain disconnected. Turn off the power supply of the load to achieve a protective effect and avoid the occurrence of fire hazards. Compared with the existing load protection circuit, the universal protection circuit can only automatically recover after the load electrical plug is unplugged or the load power supply is completely cut off, thereby improving its safety.

[0058] The universal protection circuit in the third embodiment of the present invention is usually used in toasters. Since most toaster products on the market do not have timeout or overheating protection, toaster products are also easily affected by external factors and the lifting handle is stuck and cannot rebound normally, resulting in power failure, causing continuous heating and safety hazards. The universal protection circuit in the third embodiment of the present invention can well avoid such safety hazards, and completely disconnect the power supply of the first terminal IN-L of the power input terminal, so that the toaster does not heat up in abnormal situations, and avoids the toaster from generating voltages that are harmful to the human body.

[0059] Embodiment 4:

[0060] Figure 4 This is a circuit diagram of Embodiment 4 of the universal protection circuit described in an embodiment of the present invention.

[0061] Embodiment 4 adds a current detection circuit and a varistor VDR to the universal protection circuit provided in Embodiment 1. The load in the universal protection circuit of the embodiment of the present invention is mainly household appliances for heating water, such as electric water heaters. The universal protection circuit of the embodiment of the present invention mainly plays the role of leakage protection in the load.

[0062] The universal protection circuit of the embodiment of the present invention also includes a leakage protection circuit, which is respectively connected to the output terminal OUT-L, the second terminal N of the power input terminal and the second terminal of the optocoupler device U1. The leakage protection circuit includes a leakage coil L, a bridge rectifier BD, a leakage chip U2 and a transistor Q1, the second terminal N of the power input terminal is respectively connected to the first terminal of the bridge rectifier BD and the first terminal of the load through the leakage coil L, the output terminal OUT-L is respectively connected to the second terminal of the bridge rectifier BD and the second terminal of the load through the leakage coil L, the third terminal of the bridge rectifier BD is connected to the power terminal of the leakage chip U2, the control terminal of the leakage chip U2 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the second terminal of the optocoupler device U1, and the fourth terminal of the bridge rectifier BD and the emitter of the transistor Q1 are both grounded.

[0063] It should be noted that the second end of the optocoupler device U1 is pins 1 and 2 of the optocoupler device U1 , and the first end of the optocoupler device U1 is pins 4 and 6 of the optocoupler device U1 .

[0064] The working principle of the universal protection circuit of the fourth embodiment of the present invention is:

[0065] The second end N of the power input end and the output end OUT-L pass through the leakage coil L. When the load leaks, the current passing through the leakage coil L is not 0. At this time, the leakage chip U2 detects the leakage signal and outputs a high level to drive the transistor Q1. The transistor Q1 is turned on and triggers the first end of the optocoupler device U1 in the universal protection circuit to turn on. At this time, the resistance across the second resistor R2 decreases, and the current of the entire DC circuit increases. The voltage across the coil of the electrical control device RLY meets its driving voltage. The coil of the electrical control device RLY starts to disconnect the contacts of the electrical control device RLY through the internal mechanical structure, cutting off the connection between the load and the output end OUT-L. The entire load is in a power-free state, the current detection circuit voltage disappears, and the voltage between the second ends of the optocoupler device U1 also disappears. The first end of the optocoupler device U1 forms a high impedance state, and the universal protection circuit continues to form a loop through the second resistor R2. The voltage and current of the entire loop continue to maintain the coil of the electrical control device RLY in a working state, and the contacts of the electrical control device RLY remain disconnected. Compared with the existing load protection circuit, this universal protection circuit can automatically recover only after the load electrical plug is unplugged or the load power supply is completely cut off, thereby improving its safety.

[0066] Although there are many electrical products on the market with leakage protection functions, such as instant electric water heaters, their working mode is that the main control board chip turns off the heating element of the water heater, and cannot completely turn off the power supply and control circuit of the entire appliance. If the control circuit is abnormal or leaking, it cannot be turned off. The universal protection circuit in the embodiment of the present invention can turn off the power supply provided to the load, so that the circuit of the load is completely powered off. It is necessary to manually eliminate the abnormality to automatically restore the universal protection circuit. The design of the universal protection circuit is applied to electrical products, making the use of electrical products safer and more reliable.

[0067] Embodiment five:

[0068] Figure 5 This is a circuit diagram of Embodiment 5 of the universal protection circuit described in an embodiment of the present invention.

[0069] A universal protection circuit provided in the present invention is applied to electrical equipment or electrical appliances, including a DC circuit, an electrical control device RLY, a second resistor R2, a voltage regulator tube ZD1, a first electrolytic capacitor C1, a power input end and an output end, wherein the DC circuit includes a first resistor R1, a first diode D1 and a second diode D2;

[0070] A first end of the electric control device RLY is connected to a first end IN-L of a power input end, a second end of the electric control device RLY is connected to an output end OUT-L, a voltage regulator tube ZD1 and a first electrolytic capacitor C1 are respectively connected in parallel to a third end and a fourth end of the electric control device RLY, a third end of the electric control device RLY is also connected to a cathode of a first diode D1, an anode of the first diode D1 is connected in series with a first resistor R1 and is connected to a first end of the power input end, a second end N of the power input end is respectively connected to an anode of a second diode D2 and a first end of a second resistor R2, a cathode of the second diode D2 is connected to an anode of the first electrolytic capacitor C1, a second end of the second resistor R2 is connected to a cathode of the first electrolytic capacitor C1, a varistor VDR is connected in parallel to the power input end; and an output end OUT-L is used to be connected to a load.

[0071] It should be noted that the electric control device RLY can be a normally closed relay or other electric control devices with the same working principle as the relay. The second terminal N of the power input terminal is the neutral line of the power supply, and the first terminal IN-L of the power input terminal and the output terminal OUT-L are the live wires of the power supply. The output terminal OUT-L is connected to the load. The power input terminal is connected to the varistor VDR in parallel and then connected to the alternating current. The alternating current is preferably 220V mains electricity.

[0072] The working principle of the universal protection circuit of the fifth embodiment of the present invention is:

[0073] When the voltage of the AC power is higher than the safety voltage of the load, the voltage of the loop of the universal protection circuit will increase accordingly, and the RLY coil of the electric control device can be driven. The RLY coil of the electric control device starts to disconnect the RLY contact of the electric control device through the internal mechanical structure, cutting off the power supply to the load, ensuring that the electronic components in the load or other parts connected to the load will not be damaged due to overvoltage, ensuring safety. After the voltage stabilizes, the universal protection circuit can be restored by unplugging the load's electrical plug or completely disconnecting the load power supply.

[0074] It should be noted that when the protection voltage of the universal protection circuit is 250V, the resistance value of the first resistor R1 is 3.5K 2W; the resistance value of the second resistor R2 is 6.5K 2W.

[0075] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0076] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0077] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0078] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0079] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0080] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A universal protection circuit, applied to electrical equipment or electrical appliances, characterized in that: It includes a DC circuit, an electric control device, a second resistor, a voltage regulator, a first electrolytic capacitor, an optocoupler, a power input terminal and an output terminal, wherein the DC circuit includes a first resistor, a first diode and a second diode; The first end of the electric control device is connected to the first end of the power input end, the second end of the electric control device is connected to the output end, the voltage regulator and the first electrolytic capacitor are respectively connected in parallel to the third end and the fourth end of the electric control device, the third end of the electric control device is also connected to the cathode of the first diode, the anode of the first diode is connected in series with the first resistor and is connected to the first end of the power input end, the second end of the power input end is respectively connected to the anode of the second diode and the first end of the second resistor, the cathode of the second diode is connected to the anode of the first electrolytic capacitor, the second end of the second resistor is connected to the cathode of the first electrolytic capacitor, and the first end of the optocoupler device is connected in parallel to the second resistor; Wherein, the output end is used to be connected to a load.

2. The universal protection circuit according to claim 1, characterized in that: The electric control device is a relay.

3. The universal protection circuit according to claim 1, characterized in that: The universal protection circuit also includes a current detection circuit and a varistor; the second end of the optocoupler device is connected to the current detection circuit, the input end of the current detection circuit is connected to the output end, the output end of the current detection circuit is connected in series with the load and the second end of the power supply input end, and the varistor is connected in parallel with the power supply input end.

4. The universal protection circuit according to claim 3, characterized in that: The current detection circuit includes a mutual inductor, a fourth diode connected in parallel with the secondary winding of the mutual inductor, a second electrolytic capacitor and a fifth resistor, the cathode of the fourth diode is connected to the anode of the third diode, and the cathode of the third diode is connected to the anode of the second electrolytic capacitor.

5. The universal protection circuit according to claim 1, characterized in that: The universal protection circuit also includes a timeout protection circuit, which is respectively connected to the output end, the second end of the power input end, and the second end of the optocoupler device.

6. The universal protection circuit according to claim 5, characterized in that: The timeout protection circuit includes a microcontroller unit and a bridge rectifier connected to the microcontroller unit. The microcontroller unit is also connected to the second end of the optocoupler device. The input end of the bridge rectifier is respectively connected to the output end and the second end of the power input end.

7. The universal protection circuit according to claim 1, characterized in that: The universal protection circuit also includes a leakage protection circuit, which is respectively connected to the output end, the second end of the power input end, and the second end of the optocoupler device.

8. The universal protection circuit according to claim 7, characterized in that: The leakage protection circuit includes a leakage coil, a bridge rectifier, a leakage chip and a transistor. The second end of the power input end passes through the leakage coil and is respectively connected to the first end of the bridge rectifier and the first end of the load. The output end passes through the leakage coil and is respectively connected to the second end of the bridge rectifier and the second end of the load. The third end of the bridge rectifier is connected to the power end of the leakage chip, the control end of the leakage chip is connected to the base of the transistor, the collector of the transistor is connected to the second end of the optocoupler device, and the fourth end of the bridge rectifier and the emitter of the transistor are both grounded.

9. A universal protection circuit, applied to electrical equipment or electrical appliances, characterized in that: It includes a DC circuit, an electric control device, a second resistor, a voltage regulator, a first electrolytic capacitor, a power input terminal and an output terminal, wherein the DC circuit includes a first resistor, a first diode and a second diode; The first end of the electric control device is connected to the first end of the power input end, the second end of the electric control device is connected to the output end, the voltage regulator and the first electrolytic capacitor are respectively connected in parallel to the third end and the fourth end of the electric control device, the third end of the electric control device is also connected to the cathode of the first diode, the anode of the first diode is connected in series with the first resistor and is connected to the first end of the power input end, the second end of the power input end is respectively connected to the anode of the second diode and the first end of the second resistor, the cathode of the second diode is connected to the anode of the first electrolytic capacitor, and the second end of the second resistor is connected to the cathode of the first electrolytic capacitor; Wherein, the output end is used to be connected to a load.

10. The universal protection circuit according to claim 9, characterized in that: The electric control device is a relay.

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