CN108134273B - Power safety socket circuit controlled by low-voltage detection - Google Patents
Power safety socket circuit controlled by low-voltage detection Download PDFInfo
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- CN108134273B CN108134273B CN201711297161.1A CN201711297161A CN108134273B CN 108134273 B CN108134273 B CN 108134273B CN 201711297161 A CN201711297161 A CN 201711297161A CN 108134273 B CN108134273 B CN 108134273B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/66—Structural association with built-in electrical component
- H01R13/665—Structural association with built-in electrical component with built-in electronic circuit
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/66—Structural association with built-in electrical component
- H01R13/665—Structural association with built-in electrical component with built-in electronic circuit
- H01R13/6666—Structural association with built-in electrical component with built-in electronic circuit with built-in overvoltage protection
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/66—Structural association with built-in electrical component
- H01R13/665—Structural association with built-in electrical component with built-in electronic circuit
- H01R13/6683—Structural association with built-in electrical component with built-in electronic circuit with built-in sensor
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/66—Structural association with built-in electrical component
- H01R13/70—Structural association with built-in electrical component with built-in switch
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Abstract
The invention relates to a low-voltage detection controlled power supply safety socket circuit which comprises a direct-current stabilized power supply, a voltage detection circuit and a power supply delay starting circuit. The voltage detection circuit in the power safety socket circuit for low-voltage detection control adopts a voltage division branch circuit formed by connecting a voltage reduction resistor and a voltage division resistor in series, the voltage reduction resistor is connected between the input end of a power live wire L of a socket and the electrode of a live wire jack L1 of the socket in series, two ends of the voltage division branch circuit are respectively connected with the electrode of the live wire jack L1 of the socket and the electrode of a zero wire jack N1, the voltage on the jack of the socket is reduced to 20V, and the voltage becomes a safety voltage, so that even two hands touch two electrodes in the jack at the same time, no danger exists, and the safety is very high.
Description
Technical Field
The invention relates to a power supply safety socket circuit, in particular to a low-voltage detection control power supply safety socket circuit.
Background
In order to ensure personal safety and avoid fire accidents, the state has clearly stipulated that the multifunctional sockets are not produced and sold, and only the safety sockets conforming to the national standard can be used. The safety sockets in the current market basically adopt a mechanical protection mode, and the safety sockets have certain protection effects, but are still not ideal, and mainly have the following defects: 1. in order to prevent children from getting an electric shock, a mechanical means is generally adopted, so that the power can be turned on only by applying force, or a mode that double holes are used for applying force simultaneously and jacks are opened is adopted, but potential safety hazards still exist for people with insufficient mental intelligence but enough strength such as adults, powerful children, mental patients and the like; 2. because the mechanical mode is compact in structure and complex in mechanism, faults are easy to occur after long-term and repeated use, and the mechanical safety device is difficult to insert and extract, so that some users directly dismantle the mechanical safety device, and the safety protection effect is lost; 3) Although the maximum working current allowed by the socket is regulated and marked by each manufacturer, most users do not know whether the actual working current of loads such as household heaters such as electric rice cookers, electromagnetic ovens and microwave ovens exceeds the actual working current of loads such as household heaters, so that the socket is likely to run in an overload state, the contact aging and the plastic shell deformation caused by heating are accelerated, the contact reliability and the service life are influenced, and the electric wires are heated when the situation is serious, so that fire and personal safety accidents are caused.
Because of these problems with mechanical safety sockets, electronic safety sockets have also emerged. The power safety socket circuit adopted in the existing electronic safety socket generally adopts a method of connecting a load and a sampling resistor in series to detect load current. The detection method has the advantages that under the condition that a human body touches the live wire, the current does not pass through the current sampling resistor, so that starting current is not generated to switch on a power supply, and the protection purpose is achieved. However, this circuit configuration also has drawbacks, such as: when the resistance of the human body is large, high voltage far greater than the safety voltage exists on the human body, and in addition, the human body has the danger of electric shock when both hands touch the live wire L1 and the zero wire N1 simultaneously, so that the safety is not high; the voltage change detected by the sampling resistor is not obvious when the load impedance is obviously changed, the overload load cannot be accurately detected, and the overload load is difficult to protect, meanwhile, in order to improve the detection sensitivity, the resistance value of the sampling resistor is often larger, and therefore, a relay for short-circuiting the sampling resistor is additionally arranged after the power supply is started.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a power supply safety socket circuit which is simple in circuit structure, reliable in operation and better in safety.
In order to achieve the above object, the present invention provides a low voltage detection controlled power safety socket circuit, which is characterized in that: the power supply comprises a direct-current stabilized power supply, a voltage detection circuit and a power supply delay starting circuit, wherein the voltage detection circuit comprises a voltage division branch formed by serially connecting a voltage reduction resistor and a voltage division resistor, the voltage reduction resistor is serially connected between a power supply live wire L input end of a socket and a live wire jack L1 electrode of the socket, two ends of the voltage division branch are respectively connected to the live wire jack L1 electrode of the socket and a zero wire jack N1 electrode of the socket, the power supply zero wire N input end of the socket is electrically connected with the zero wire jack N1 electrode of the socket, the sum of the resistance of the voltage reduction resistor and the voltage division resistor is larger than 1MΩ, the resistance ratio between the voltage reduction resistor and the voltage division resistor is 10:1-15:1, the voltage division resistor is formed by serially connecting a first voltage division resistor and a second voltage division resistor, the voltage between the voltage division point A of the first voltage division resistor and the second voltage division resistor and the power supply zero wire N input end of the socket is an output signal of the voltage detection circuit, and the detection output signal end is connected with the power supply delay starting circuit input end; the power supply delay starting circuit comprises a starting relay KA and a delay driving circuit thereof, wherein normally open contacts of the starting relay KA are connected in parallel with two ends of the voltage dropping resistor, when the detection output signal is at a high level, the delay driving circuit enables a coil of the starting relay KA to lose electricity and disconnect, and when the detection output signal is at a low level, the delay driving circuit enables the coil of the starting relay KA to delay to obtain electricity suction; the direct-current stabilized power supply provides a direct-current working power supply for the power delay starting circuit.
The voltage detection circuit in the power safety socket circuit for low-voltage detection control adopts a voltage division branch circuit formed by connecting a voltage reduction resistor and a voltage division resistor in series, the voltage reduction resistor is connected between the input end of a power live wire L of a socket and the electrode of a live wire jack L1 of the socket in series, two ends of the voltage division branch circuit are respectively connected with the electrode of the live wire jack L1 of the socket and the electrode of a zero wire jack N1, the voltage on the jack of the socket is reduced to 20V, and the voltage becomes a safety voltage, so that even two hands touch two electrodes in the jack at the same time, no danger exists, and the safety is very high.
The invention will be further described with reference to the drawings and specific examples.
Drawings
FIG. 1 is an electrical schematic diagram of a specific embodiment of a voltage detection circuit of the present invention;
FIG. 2 is an electrical schematic diagram of an embodiment of a power delay turn-on circuit of the present invention;
FIG. 3 is an electrical schematic diagram of an embodiment of an idle automatic shutdown circuit of the present invention;
FIG. 4 is an electrical schematic diagram of an embodiment of a start-up overload and short-circuit protection circuit according to the present invention;
FIG. 5 is an electrical schematic diagram of an embodiment of an overload and short-circuit protection circuit according to the present invention;
FIG. 6 is an electrical schematic diagram of an embodiment of a zero reset circuit of the present invention;
fig. 7 is an electrical schematic diagram of a dc voltage stabilizing circuit according to an embodiment of the present invention.
Detailed Description
The invention discloses a low-voltage detection controlled power supply safety socket circuit which comprises a direct-current stabilized power supply, a voltage detection circuit and a power supply delay starting circuit, wherein the direct-current stabilized power supply provides a direct-current working power supply for the power supply delay starting circuit and other circuits.
As shown in fig. 1, the voltage detection circuit includes a voltage division branch formed by connecting a voltage-reducing resistor and a voltage-dividing resistor in series, the voltage-reducing resistor is connected in series between a power live wire L input end of the socket and a live wire jack L1 electrode of the socket, two ends of the voltage division branch are respectively connected to the live wire jack L1 electrode and the zero wire jack N1 electrode of the socket, and the power zero wire N input end of the socket is electrically connected with the zero wire jack N1 electrode of the socket. In order to ensure safety and also to ensure detection sensitivity, the proper range should be selected for the sum of the resistances of the voltage-reducing resistor and the voltage-dividing resistor, in this embodiment, the voltage-reducing resistor takes 1mΩ, and the ratio of the resistances between the voltage-reducing resistor and the voltage-dividing resistor is 10:1, so that the no-load voltage between the two jacks of the socket is reduced to about 20V. In this embodiment, the voltage dividing resistor is formed by connecting a first voltage dividing resistor R3 and a second voltage dividing resistor R4 in series, the voltage between the voltage dividing point a of the first voltage dividing resistor R3 and the second voltage dividing resistor R4 and the N (zero line) power input end of the socket is an output signal of the voltage detecting circuit, and the detecting output signal end is connected with the power delay starting circuit input end a.
The power delay starting circuit comprises a starting relay KA and a delay driving circuit thereof, normally open contacts of the starting relay KA are connected in parallel with two ends of the voltage reduction resistor, in the specific embodiment, when the load is unloaded, through voltage division of the first voltage division resistor R3 and the second voltage division resistor R4, the level of a voltage division point A is about 2V, namely, the detection output signal is high, at the moment, the corresponding delay driving circuit enables the starting relay KA coil to be deenergized and disconnected, and when a load is connected, the level of the voltage division point A is below 0.5V, namely, the detection output signal is low, and at the moment, the corresponding delay driving circuit enables the starting relay KA coil to delay to be electrified and attracted. The specific circuit structure of the delay driving circuit is not particularly required, and various circuit forms can be adopted as long as the requirements are met.
As shown in fig. 2, in this embodiment, the power delay turn-on circuit includes an input level discriminating circuit and a delay driving circuit; the input level judging circuit comprises a delay resistor R6 and an NPN first switching triode T1, wherein the delay resistor R6 is connected between a collector electrode of the first switching triode T1 and a power supply anode Vcc, an emitter electrode of the first switching triode T1 is connected to a power supply cathode, a delay capacitor C2 is connected in parallel between the collector electrode and the emitter electrode of the first switching triode T1, the delay resistor R6 and the delay capacitor C2 form a delay charging branch, and a base electrode of the first switching triode T1 is a power supply delay starting circuit input end A; the delay driving circuit comprises a first inverter U1-1 and a PNP second switching triode T2, wherein a turn-on relay KA coil is connected between a collector of the second switching triode T2 and a power supply negative electrode, an emitter of the second switching triode T2 is connected with a power supply positive electrode Vcc, an input end (namely an input end E of the delay driving circuit) of the first inverter U1-1 is connected with the collector of the first switching triode T1 through a first current limiting resistor R7, an output end of the first inverter U1-1 is connected with a base of the second switching triode T2 through a second current limiting resistor R9, and a first feedback resistor R8 and a first feedback diode VD3 serial branch circuit are connected between the collector of the second switching triode T2 and the input end of the first inverter U1-1 to form the delay driving circuit.
In order to further improve the safety, the step-down resistor is preferably divided into more than one resistor connected in series, so as to avoid electric shock hazard caused by the fact that the resistor fails to be conducted when a single resistor is adopted, and therefore the step-down resistor is formed by connecting the first step-down resistor R1 and the second step-down resistor R2 in series, and the reliability can be safely improved.
The working principle of the low-voltage detection control power supply safety socket circuit is as follows:
when the voltage detection circuit is in no-load state, the voltage at two ends of the voltage division branch is reduced by the voltage reduction resistor, the voltage at two ends of the voltage division branch is about 20V, the voltage of the first voltage division resistor R3 and the voltage division of the second voltage division resistor R4 is about 2V, namely the detection output signal is far higher than the dead zone voltage of 0.5V, the voltage of the voltage division point A is confirmed to be high level, the high level is input to the base electrode of the first switching triode T1 in the delay driving circuit, the first switching triode T1 is conducted, the delay capacitor C2 is discharged to be low level due to quick discharging and slow charging, the output high level of the first inverter U1-1 is cut off, the opening relay coil is in power failure, and the normally open contact KA1 is disconnected, so that the voltage on the jack of the socket is kept in a safe voltage range of about 20V. And the human body resistance in the low-voltage state is at least more than 100k omega, at the moment, if a person touches an electrode in the jack by mistake, the level of the voltage dividing point A is still far more than 0.5V dead zone voltage, namely the detection output signal is still in a high level, the coil of the starting relay KA is powered off, and the normally open contact KA1 is disconnected, so that the voltage on the jack of the socket is kept in a safe voltage range of about 20V, no electric shock hazard exists, and the aim of safety protection is achieved.
When a load with more than 1W is inserted into the socket, as the impedance of the load is far smaller than that of the voltage dividing resistor, the voltage is reduced by the voltage reducing resistor and the voltage is divided by the first voltage dividing resistor R3 and the second voltage dividing resistor R4, the level of the voltage dividing point A is always below 0.5V, namely the detection output signal is low level, the low level is input to the base electrode of the first switching triode T1 in the delay driving circuit, the first switching triode T1 is cut off, the delay capacitor C2 is charged through the delay resistor R6 and gradually becomes high level, the output of the first inverter U1-1 is low level, the second switching triode T2 is conducted, the relay KA coil is started to be electrified, the normally open contact KA1 is closed, the jack of the socket is powered on, and the load is electrified.
In order to further perfect the circuit and ensure that the socket can be restored to a safe voltage state after the load is removed, the power supply safety socket circuit is also provided with an idle automatic shutdown circuit. The no-load automatic shutdown circuit comprises a load detection unit and a comparison and delay blocking unit, wherein the load detection unit detects the working current of a socket, the output end of the load detection unit is connected with the input end of the comparison and delay blocking unit, the output end of the comparison and delay blocking unit is connected with the input end E of a first phase inverter in the delay driving circuit in a line-and-line mode, and when the working current of the socket is smaller than a preset value, the output end of the comparison and delay blocking unit outputs a low level.
In this embodiment, as shown in fig. 3, the load detection unit includes a current transformer LH1, the primary of the current transformer LH1 is connected to a power input line between the input end of a power zero line N of the socket and the electrode of the zero line jack N1 of the socket, the comparing and delay blocking unit includes a first comparator U2-1, a second inverter U1-2 and an RC delay circuit, the first comparator U2-1 adopts an OC output comparator, the output end of the first comparator U2-1 is connected with the input end of the second inverter U1-2 through a discharge resistor, the non-inverting input end of the first comparator U2-1 is provided with a voltage dividing circuit composed of a resistor R13 and a resistor R14 to provide a comparison reference level, the output end of the current transformer LH1 is connected in parallel with a first anti-saturation diode VD1, a second anti-saturation diode R5 and an anti-interference capacitor C1, the output end of the current transformer LH1 is connected with the inverting input end of the first comparator U2-1 through a discharge resistor R15, the output end of the first comparator U2-1 is connected with the inverting end of the second inverter U2-1 through a non-inverting resistor, the inverting circuit is connected with the other end of the inverting circuit of the second resistor v 2-C1 as an idle circuit, and the output end of the inverting circuit is connected with the inverting output end of the second resistor v 2 is connected with the second resistor v 1.
The working principle of the no-load automatic shutdown circuit is as follows:
when the load is normally plugged into the socket, as the impedance of the load is far smaller than that of the voltage dividing resistor, the voltage is reduced by the voltage reducing resistor and the voltage is divided by the first voltage dividing resistor R3 and the second voltage dividing resistor R4, the level of the voltage dividing point A is always below 0.5V, namely the detection output signal is low level, the low level is input to the base electrode of the first switching triode T1 in the delay driving circuit, the first switching triode T1 is cut off, the delay capacitor C2 is charged through the delay resistor R6 and gradually becomes high level, the output low level of the first inverter U1-1 is conducted by the second switching triode T2, the opening relay KA coil is electrified, the normally open contact KA1 is closed, the socket of the socket is powered on, and the load is electrified. Meanwhile, the induced voltage at the output end of the current transformer LH1 is larger than the reference level at the non-inverting input end of the first comparator U2-1 in the no-load automatic shutdown circuit, the first comparator U2-1 outputs a low level, the second inverter U1-2 outputs a high level, and the input end of the first inverter U1-1 in the power delay starting circuit is not blocked by the isolation of the first isolation diode VD5, so that the influence on the input end of the first inverter U1-1 in the power delay starting circuit is avoided.
When the load is removed from the socket, the induced voltage at the output end of the current transformer LH1 is smaller than the reference level at the non-inverting input end of the first comparator U2-1 in the no-load automatic shutdown circuit, the first comparator U2-1 outputs a high level, the second inverter U1-2 outputs a low level, the input end of the first inverter U1-1 in the power delay starting circuit is pulled down through the first isolation diode VD5 to form a blocking state, the output end of the first inverter U1-1 is a high level, the starting relay KA coil is powered off, and the normally open contact KA1 is disconnected, so that the voltage on the jack of the socket is recovered to a safe voltage range of about 20V, and the power delay starting circuit is recovered to an initial state.
In order to prevent the spark generated by the starting power supply in overload and short circuit conditions, the starting overload and short circuit protection circuit is preferably further arranged in the embodiment. As shown in fig. 4, the overload starting and short-circuit protection circuit includes a second comparator U2-2 and a third inverter U1-3, the second comparator U2-2 adopts an OC output type comparator, a voltage dividing circuit composed of a resistor R18 and a resistor R19 is arranged at the in-phase input end of the second comparator U2-2 to provide a comparison reference level, a voltage between the input end of a power zero line N of the socket and the live wire jack L1 of the socket is input as the inverting input end of the second comparator U2-2, that is, the live wire jack L1 is connected to the inverting input end of the second comparator U2-2 through a fourth current limiting resistor R17, and the voltage signal is selected as a sampling signal, so that a tiny signal can be sensed. In order to prevent the second comparator U2-2 from being damaged, the inverting input end of the second comparator U2-2 is connected with the first limiting diode VD6, the second limiting diode VD7 and the anti-interference capacitor C4 in parallel, the output end of the second comparator U2-2 is connected with the input end of the third inverter U1-3 through the third limiting resistor R20, the output end of the third inverter U1-3 is connected with the cathode of the second isolation diode VD8, the anode of the second isolation diode VD8 is used as the output end of the starting overload and short circuit protection circuit and is connected with the input end E of the first inverter U1-1 in a line-and-line mode in the delay driving circuit, the second charging capacitor C5 is connected between the input end of the third inverter U1-3 and the negative electrode of the power supply, the second charging resistor R21 is connected between the input end of the third inverter U1-3 and the positive electrode Vcc of the power supply, and the resistance ratio of the second charging resistor R21 to the third limiting resistor R20 is about 20:1, so as to ensure that the charging and discharging are fast.
The working principle of the starting overload and short-circuit protection circuit is as follows:
in a normal working state, the level of the inverting input end of the second comparator U2-2 is higher than the reference level of the non-inverting input end of the second comparator U2-2 when the mains supply is in a positive half cycle, the second comparator U2-2 outputs a low level, and the working power supply charges the second charging capacitor C5 through the second charging resistor R21, but the resistance value of the third current limiting resistor R20 is far smaller than the resistance value of the second charging resistor R21, and the discharging current is larger than the charging current, so that the input end of the third inverter U1-3 is still in a low level, and the output of the third inverter U1-3 is in a high level, so that the working of other circuits is not influenced; when overload or short circuit occurs, the level of the inverting input end of the second comparator U2-2 is always lower than the reference level of the non-inverting input end of the second comparator U2-2, the output OC gate of the second comparator U2-2 is cut off, the working power supply charges the second charging capacitor C5 through the second charging resistor R21, and no discharging passage exists, so that the input end of the third inverter U1-3 is high level, the output of the third inverter U1-3 is low level, the third inverter U1-3 is blocked through the low level clamp of the second isolation diode VD8, the power supply delay starting circuit cannot be started, the starting relay KA coil is powered off, the normally open contact KA1 is disconnected, and the socket has no power supply output.
In order to further improve the safety, the embodiment is preferably further provided with an operation overload and short-circuit protection circuit. As shown in fig. 5, the overload and short-circuit protection circuit includes a comparing unit, the comparing unit includes a third comparator U2-3 and a third isolation diode VD10, the non-inverting input end of the third comparator U2-3 is provided with a voltage dividing circuit composed of a resistor R23 and a resistor R24 to provide a comparison reference level, the inverting input end of the third comparator U2-3 is provided with a voltage dividing circuit to input a voltage signal related to the zero line jack N1 electrode of the socket, the voltage dividing circuit composed of a resistor R22 and a resistor R0 is specifically connected between the positive electrode Vcc of the power supply and the zero line jack N1 electrode of the socket, the voltage dividing point is connected with the inverting input end of the third comparator U2-3, and an anti-interference capacitor C6 is preferably further provided between the inverting input end of the third comparator U2-3 and the negative electrode of the power supply. The output end of the third comparator U2-3 is provided with a pull-up resistor R26, a positive feedback branch formed by connecting a second feedback resistor R25 and a second feedback diode VD9 in series branch is arranged between the output end of the third comparator U2-3 and the in-phase input end of the third comparator U2-3, the output end of the third comparator U2-3 is connected with the cathode of a third isolation diode VD10, and the anode of the third isolation diode VD10 is used as the output end of the overload and short circuit protection circuit to be connected with the input end E of the delay starting circuit in a line-and-line mode.
The working principle of the operation overload and short-circuit protection circuit is as follows:
in a normal working state, the level of the non-inverting input end of the third comparator U2-3 divided by the voltage dividing circuit formed by the resistor R23 and the resistor R24 is slightly higher than the level of the inverting input end of the third comparator U2-3 divided by the voltage dividing circuit formed by the resistor R22 and the resistor R0, the third comparator U2-3 outputs a high level, and the input end of the first inverter U1-1 in the power delay starting circuit is not blocked by the isolation of the third isolation diode VD10, so that the influence is not caused. When overload and short circuit occur suddenly in operation, the level of the inverting input end of the third comparator U2-3 rises and is higher than the level of the non-inverting input end of the third comparator U2-3, the third comparator U2-3 outputs a low level, the low voltage clamp of the third isolation diode VD10 is used for blocking, the power supply delay starting circuit cannot be started, the starting relay KA coil is powered off, the normally open contact KA1 is disconnected, and the socket has no power supply output. In order to prevent the self-recovery after the power supply is cut off, a positive feedback branch consisting of a second feedback resistor R25 and a second feedback diode VD9 connected in series is further arranged in the operation overload and short-circuit protection circuit, after the output low level of the third comparator U2-3 is blocked, the power supply is fed back through the positive feedback branch, so that the level of the non-inverting input end of the third comparator U2-3 is always lower than the level of the inverting input end of the third comparator U2-3, the output end of the third comparator U2-3 is kept at a low level, a power supply delay starting circuit cannot be started, the starting relay KA coil is in power failure, the normally open contact KA1 is disconnected, and the socket has no power supply output.
After the overload and short-circuit protection circuit is operated, the blocking party must be relieved to work normally again due to the self-locking effect, and the power supply is cut off through the air switch, so that the power supply is reset, but the defects of instant power failure and troublesome operation can occur. In this embodiment, a clear reset circuit is preferably further provided, and the circuit is simple and practical and is easy to operate. As shown in fig. 6, the zero clearing reset circuit is formed by a monostable human body touch circuit, in a normal state, the monostable human body touch circuit outputs a low level, when a human body touches, the monostable human body touch circuit outputs a high level, an output end of the monostable human body touch circuit is connected with an anode of a fourth isolation diode VD4, and a cathode of the fourth isolation diode VD4 is used as an output end of the zero clearing reset circuit and is connected with an in-phase input end of a third comparator U2-3 in the operation overload and short circuit protection circuit.
The monostable human body touch circuit comprises a fourth inverter U1-4 and a touch sheet M, a load impedance branch formed by connecting a capacitor C7 and a resistor R27 in parallel is arranged between the input end of the fourth inverter U1-4 and a power supply positive electrode VCC1, the touch sheet M is connected with the input end of the fourth inverter U1-4 through a panel capacitor (such as a glass panel capacitor C8 or an organic glass panel capacitor), the output end of the fourth inverter U1-4 is connected with the anode of a fourth isolation diode VD4, and the cathode of the fourth isolation diode VD4 is used as the output end of a zero clearing reset circuit to be connected with the non-inverting input end of a third comparator U2-3 in the operation overload and short circuit protection circuit.
The zero clearing reset circuit has simple principle: before a human body touches, the input end of the fourth inverter U1-4 is high level, the output is low level, and the zero clearing and resetting effects are not achieved; after the human body touches, the input end of the fourth inverter U1-4 is low-level, the output end is high-level, and the non-inverting input end of the third comparator U2-3 in the operation overload and short circuit protection circuit is high-level through the fourth isolation diode VD4, so that the zero clearing and resetting effects and the blocking and releasing effects are realized.
In the power safety socket circuit controlled by the low-voltage detection, there is no special requirement for a direct-current stabilized power supply, however, in order to reduce the power consumption of the direct-current stabilized power supply when in no-load, as shown in fig. 7, in this embodiment, the direct-current stabilized power supply includes a half-wave rectifying unit, a primary voltage stabilizing unit and a precise voltage stabilizing unit; the half-wave rectification unit comprises a first rectification diode VD12, a second rectification diode VD13 and an RC voltage reduction branch, one end of the RC voltage reduction branch is connected with the anode of the first rectification diode VD12, the other end of RC voltage reduction branch is connected with the input end of a power live wire L of the socket, the cathode of the second rectification diode VD13 is connected with the anode of the first rectification diode VD12, and the anode of the second rectification diode VD13 is connected with the input end of a power zero line N of the socket; the primary voltage stabilizing unit comprises a first unidirectional thyristor VT1, a first voltage stabilizing diode VD14, a fourth current limiting resistor R30, an anti-interference capacitor C10 and a first filter capacitor C11, wherein the anode of the first unidirectional thyristor VT1 is connected with the anode of a first rectifying diode VT 12, the cathode of the first unidirectional thyristor VT1 is connected with the input end of a power zero line N of a socket, after the first voltage stabilizing diode VD14 and the fourth current limiting resistor R30 are connected in series, the cathode of the first voltage stabilizing diode VD14 is connected with the cathode of the first rectifying diode VD12, the anode of the first voltage stabilizing diode VD14 is connected with the gate of the first unidirectional thyristor VT1, the anti-interference capacitor C10 and the fourth current limiting resistor R30 are connected in parallel and then are connected with the cathode of the first unidirectional thyristor VT1 and the gate, the first filter capacitor C11 is connected between the cathode of the first rectifying diode 12 and the input end of the power zero line N of the socket, and the cathode of the first rectifying diode 12 is the positive output end VCC1 of the primary voltage stabilizing unit; the precise voltage stabilizing unit comprises a three-terminal voltage stabilizer U3, an input filter capacitor V12 and a second filter capacitor C13, wherein the input end of the three-terminal voltage stabilizer U3 is connected with the power supply positive electrode output end of the primary voltage stabilizing unit, the input filter capacitor V12 is connected between the input end of the three-terminal voltage stabilizer U3 and the power supply zero line N input end of the socket, the second filter capacitor C13 is connected between the output end of the three-terminal voltage stabilizer U3 and the power supply zero line N input end of the socket, the output end of the three-terminal voltage stabilizer U3 is the power supply positive electrode VCC2 output end of the precise voltage stabilizing unit, the voltage output provides a high-precision direct current power supply for a first comparator U2-1, a second comparator U2-2 and a voltage dividing branch circuit of a reference level in the circuit, and the power supply positive electrode VCC1 provides a direct current working power supply for the rest parts of the circuit.
In the no-load state, the voltage drop of the first unidirectional thyristor VT1 and the second rectifier diode VD13 is very low, so that the static power consumption is approximately zero.
The above embodiments are only for illustrating the inventive concept of the present invention and not for limiting the protection of the claims of the present invention, and all the insubstantial modifications of the present invention using the concept shall fall within the protection scope of the present invention.
Claims (9)
1. A low-voltage detection controlled power safety socket circuit is characterized in that: the direct-current voltage-stabilizing power supply, the voltage detection circuit and the power delay starting circuit are included, the voltage detection circuit comprises a voltage division branch formed by serially connecting a voltage-reducing resistor and a voltage-dividing resistor, the voltage-reducing resistor is serially connected between a power live wire L input end of a socket and a live wire jack L1 electrode of the socket, two ends of the voltage-dividing branch are respectively connected to the live wire jack L1 electrode of the socket and a zero wire jack N1 electrode of the socket, the power zero wire N input end of the socket is electrically connected with the zero wire jack N1 electrode of the socket, the sum of the resistance of the voltage-reducing resistor and the voltage-dividing resistor is larger than 1MΩ, the resistance ratio between the voltage-reducing resistor and the voltage-dividing resistor is 10:1-15:1, the voltage-dividing resistor is formed by serially connecting a first voltage-dividing resistor and a second voltage-dividing resistor, the voltage between the voltage dividing point A of the first voltage-dividing resistor and the second voltage-dividing resistor and the power zero wire N input end of the socket is an output signal of the voltage detection circuit, and the detection output signal end is connected with the power delay starting circuit input end; the power supply delay starting circuit comprises a starting relay KA and a delay driving circuit thereof, wherein normally open contacts of the starting relay KA are connected in parallel with two ends of the voltage dropping resistor, when the detection output signal is at a high level, the delay driving circuit enables a coil of the starting relay KA to lose electricity and disconnect, and when the detection output signal is at a low level, the delay driving circuit enables the coil of the starting relay KA to delay to obtain electricity suction; the direct-current stabilized power supply provides a direct-current working power supply for the power delay starting circuit.
2. The low voltage detection controlled power safety outlet circuit of claim 1, wherein: the power delay starting circuit comprises an input level judging circuit and a delay driving circuit; the input level judging circuit comprises a delay resistor and an NPN type first switching triode, wherein the delay resistor is connected between a collector electrode of the first switching triode and a positive electrode of a power supply, an emitting electrode of the first switching triode is connected to a negative electrode of the power supply, a delay capacitor is connected in parallel between the collector electrode and the emitting electrode of the first switching triode, the delay resistor and the delay capacitor form a delay charging branch circuit, and a base electrode of the first switching triode is an input end of the power supply delay starting circuit; the delay driving circuit comprises a first inverter and a PNP second switching triode, wherein a KA coil of the starting relay is connected between a collector electrode of the second switching triode and a power supply negative electrode, an emitter electrode of the second switching triode is connected with a power supply positive electrode, an input end of the first inverter is connected with the collector electrode of the first switching triode through a first current limiting resistor, an output end of the first inverter is connected with a base electrode of the second switching triode through a second current limiting resistor, and a first feedback resistor and a first feedback diode serial branch circuit are connected between the collector electrode of the second switching triode and an input end of the first inverter to form the delay driving circuit.
3. The low voltage detection controlled power safety outlet circuit according to any one of claims 1-2, wherein: the automatic no-load shutdown circuit comprises a load detection unit and a comparison and delay blocking unit, wherein the load detection unit detects the working current of the socket, the output end of the load detection unit is connected with the input end of the comparison and delay blocking unit, the output end of the comparison and delay blocking unit is connected with the input end of a first phase inverter in the power delay starting circuit in a line-and-line mode, and when the working current of the socket is smaller than a preset value, the output end of the comparison and delay blocking unit outputs a low level.
4. A low voltage detection controlled power safety outlet circuit according to claim 3, wherein: the load detection unit comprises a current transformer, the current transformer is connected to a power input line between a power zero line N input end of a socket and a zero line jack N1 electrode of the socket, the comparison and delay blocking unit comprises a first comparator, a second inverter and an RC delay circuit, a voltage dividing circuit is arranged at an in-phase input end of the first comparator to provide a comparison reference level, an output end of the current transformer is connected with an inverting input end of the first comparator, an output end of the first comparator is connected with an input end of the second inverter through a discharging resistor, the RC delay circuit is formed by serially connecting a delay resistor and a delay capacitor, the midpoint of the RC delay circuit is connected with an input end of the second inverter, the other end of the delay capacitor is connected with a power negative electrode, the other end of the delay resistor is connected with a collector electrode of the second switching triode, an output end of the second inverter is connected with a cathode of the first isolation diode, and an anode of the first isolation diode is used as an output end of the no-load automatic shutdown circuit.
5. The low voltage detection controlled power safety outlet circuit of claim 1, wherein: the power supply zero line N input end of the socket and the live wire jack L1 of the socket are used as inverting input ends of the second comparator to input, the output end of the second comparator is connected with the input end of the third inverter through a third current limiting resistor, the output end of the third inverter is connected with the cathode of a second isolation diode, the anode of the second isolation diode is used as the output end of the power supply overload and short circuit protection circuit to be connected with the input end of a first inverter in the delay driving circuit in a line-with-line mode, a second charging capacitor is connected between the input end of the third inverter and the power supply cathode, and a second charging resistor is connected between the input end of the third inverter and the power supply anode, and the resistance ratio of the second charging resistor to the third current limiting resistor is 20:1.
6. The low voltage detection controlled power safety outlet circuit of claim 1, wherein: the overload and short-circuit protection circuit comprises a comparison unit, the comparison unit comprises a third comparator and a third isolation diode, the in-phase input end of the third comparator is provided with a voltage dividing circuit for providing comparison reference level, the inverting input end of the third comparator is provided with a voltage dividing circuit for inputting voltage signals related to the N1 electrode of the zero line jack of the socket, the output end of the third comparator is provided with a pull-up resistor, a positive feedback branch circuit formed by connecting a second feedback resistor and a second feedback diode in series branch circuit is arranged between the output end of the third comparator and the in-phase input end of the third comparator, the output end of the third comparator is connected with the cathode of the third isolation diode, and the anode of the third isolation diode is used as the output end of the overload and short-circuit protection circuit for operation and is connected with the input end of the first inverter in the delay driving circuit in a line-and-with mode.
7. The low voltage detection controlled power safety outlet circuit of claim 6, wherein: the zero clearing reset circuit is composed of a monostable human body touch circuit, the monostable human body touch circuit outputs a low level in a normal state, the monostable human body touch circuit outputs a high level when in human body touch, the output end of the monostable human body touch circuit is connected with the anode of a fourth isolation diode, and the cathode of the fourth isolation diode is used as the output end of the zero clearing reset circuit and is connected with the non-inverting input end of a third comparator in the overload operation and short circuit protection circuit.
8. The low voltage detection controlled power safety outlet circuit of claim 7, wherein: the monostable human body touch circuit comprises a fourth inverter and a touch sheet, a load impedance branch circuit formed by connecting a capacitor and a resistor in parallel is arranged between the input end of the fourth inverter and the positive electrode of a power supply, the touch sheet is connected with the input end of the fourth inverter through a panel capacitor, the output end of the fourth inverter is connected with the anode of a fourth isolation diode, and the cathode of the fourth isolation diode is used as the output end of a zero clearing reset circuit and is connected with the in-phase input end of a third comparator in the operation overload and short circuit protection circuit.
9. The low voltage detection controlled power safety outlet circuit of claim 1, wherein: the direct-current stabilized power supply comprises a half-wave rectifying unit, a primary voltage stabilizing unit and a precise voltage stabilizing unit; the half-wave rectifying unit comprises a first rectifying diode, a second rectifying diode and an RC voltage-reducing branch, one end of the RC voltage-reducing branch is connected with the anode of the first rectifying diode, the other end of the RC voltage-reducing branch is connected with the input end of a power live wire L of the socket, the cathode of the second rectifying diode is connected with the anode of the first rectifying diode, and the anode of the second rectifying diode is connected with the input end of a power null wire N of the socket; the primary voltage stabilizing unit comprises a first unidirectional thyristor, a first voltage stabilizing diode, a fourth current limiting resistor, an anti-interference capacitor and a first filter capacitor, wherein the anode of the first unidirectional thyristor is connected with the anode of a first rectifying diode, the cathode of the first unidirectional thyristor is connected with the input end of a power zero line N of a socket, after the first voltage stabilizing diode and the fourth current limiting resistor are connected in series, the cathode of the first voltage stabilizing diode is connected with the cathode of the first rectifying diode, the anode of the first voltage stabilizing diode is connected with the gate of the first unidirectional thyristor, the anti-interference capacitor and the fourth current limiting resistor are connected in parallel and then are connected with the cathode and the gate of the first unidirectional thyristor, the first filter capacitor is connected between the cathode of the first rectifying diode and the input end of the power zero line N of the socket, and the cathode end of the first rectifying diode is the output end of the power positive electrode of the primary voltage stabilizing unit; the precise voltage stabilizing unit comprises a three-terminal voltage stabilizer, an input filter capacitor and a second filter capacitor, wherein the input end of the three-terminal voltage stabilizer is connected with the positive output end of the power supply of the primary voltage stabilizing unit, the input filter capacitor is connected between the input end of the three-terminal voltage stabilizer and the input end of the power supply zero line N of the socket, the second filter capacitor is connected between the output end of the three-terminal voltage stabilizer and the input end of the power supply zero line N of the socket, and the output end of the three-terminal voltage stabilizer is the positive output end of the power supply of the precise voltage stabilizing unit.
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| CN110753421B (en) * | 2018-07-04 | 2023-09-19 | 晨辉光宝科技股份有限公司 | LED drive circuit and lamp tube |
| CN109239620B (en) * | 2018-10-26 | 2024-03-19 | 恒银金融科技股份有限公司 | ATX power supply maintenance detection circuit |
| CN111949107B (en) * | 2019-05-15 | 2023-11-07 | 北京小米移动软件有限公司 | Method and device for controlling electronic equipment comprising USB Type-C interface and electronic equipment |
| CN110389552A (en) * | 2019-07-25 | 2019-10-29 | 中国科学院西安光学精密机械研究所 | A kind of calibration that can eliminate risk and power control circuit |
| CN111799608A (en) * | 2020-07-09 | 2020-10-20 | 东莞市贝恩电子科技有限公司 | Socket circuit and socket with same |
| US11231151B1 (en) * | 2021-04-16 | 2022-01-25 | Shenzhen Ekola Lighiing Technology Co., Ltd. | Smart net light strings |
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