CN107069655B - Voltage protection circuit - Google Patents
Voltage protection circuit Download PDFInfo
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- CN107069655B CN107069655B CN201710418303.9A CN201710418303A CN107069655B CN 107069655 B CN107069655 B CN 107069655B CN 201710418303 A CN201710418303 A CN 201710418303A CN 107069655 B CN107069655 B CN 107069655B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
- H02H3/207—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage also responsive to under-voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0061—Details of emergency protective circuit arrangements concerning transmission of signals
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- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The invention discloses a voltage protection circuit, which comprises a rectifying circuit connected with an alternating current power supply, and a voltage signal acquisition circuit, wherein the input end of the voltage signal acquisition circuit is connected with the rectifying circuit; the input end of the voltage follower is connected with the voltage signal acquisition circuit; the anode of a light emitting diode in the optical coupler is connected with the output end of the voltage follower, and the cathode of the light emitting diode is connected with the output negative wire of the rectifying circuit; the collector of a photosensitive semiconductor tube in the optical coupler is connected with a power supply through a resistor, and the emitter of the photosensitive semiconductor tube is grounded; the input end of the control module is connected with the collector of the photosensitive semiconductor tube, and the output end of the control module is connected with the control end of the controllable switch; the controllable switch is arranged on an output positive electrode line between the alternating current power supply and the load. This application has realized the electrical isolation between voltage follower's the input and optoelectronic coupler's the output, and output signal does not have the influence to the input, and the interference killing feature is strong.
Description
Technical Field
The invention relates to the technical field of voltage protection, in particular to a voltage protection circuit.
Background
Voltage protection circuits play a very important role in power systems. The voltage protection circuit comprises an overvoltage protection circuit and an undervoltage protection circuit, and the working principle of the voltage protection circuit is as follows: when the voltage input to the load by the power supply exceeds a preset threshold value, the voltage protection circuit acts to protect the power supply and the load. Many voltage protection circuits have appeared in the prior art, but all of the voltage protection circuits have the defects of easy interference and poor interference resistance.
Therefore, how to provide a solution to the above technical problem is a problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide a voltage protection circuit, which realizes the one-way transmission of electric signals, realizes the electrical isolation between the input end of a voltage follower and the output end of a photoelectric coupler, has no influence on the input end by output signals and has strong anti-jamming capability.
In order to solve the above technical problem, the present invention provides a voltage protection circuit, which is applied to an ac power input system, wherein the ac power input system includes an ac power, the ac power is connected to a load, and the voltage protection circuit includes:
a rectifying circuit connected to the AC power supply;
the input end of the voltage signal acquisition circuit is connected with the rectifying circuit;
the input end of the voltage follower is connected with the voltage signal acquisition circuit;
the anode of a light emitting diode in the optical coupler is connected with the output end of the voltage follower, and the cathode of the light emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a photosensitive semiconductor tube in the optocoupler is connected with a power supply through a resistor, and an emitter of the photosensitive semiconductor tube is grounded;
the control module is used for controlling the controllable switch to be switched off when the direct-current voltage output by the rectifying circuit is not within a preset range; the controllable switch is arranged on a live wire between the alternating current power supply and a load.
Preferably, the voltage signal acquisition circuit comprises a first voltage signal acquisition circuit, and an input end of the first voltage signal acquisition circuit is connected with the rectification circuit;
the voltage follower comprises a first voltage follower, and the input end of the first voltage follower is connected with the output end of the first voltage signal acquisition circuit;
the optical coupler comprises a first optical coupler, the anode of a first light emitting diode in the first optical coupler is connected with the output end of the first voltage signal acquisition circuit, and the cathode of the first light emitting diode is connected with the output negative wire of the rectification circuit; a collector of a first photosensitive semiconductor tube in the first optocoupler is connected with a power supply through a resistor, an emitter of the first photosensitive semiconductor tube is grounded, and the first light-emitting diode is conducted when the direct-current voltage exceeds an overvoltage threshold;
the control module comprises a first control module, wherein the input end of the first control module is connected with the collector of the first photosensitive semiconductor tube, and the output end of the first control module is connected with a control end connecting block of the controllable switch and used for controlling the controllable switch to be switched off when the first light-emitting diode is switched on.
Preferably, the first voltage signal acquisition circuit includes a first resistor and a second resistor, a first end of the first resistor is used as an input end of the voltage signal acquisition circuit and connected to an output positive line of the rectifier circuit, a second end of the first resistor is connected to a first end of the second resistor, a common end of the first resistor is used as an output end of the first voltage signal acquisition circuit, and a second end of the second resistor is connected to an output negative line of the rectifier circuit.
Preferably, the voltage signal acquisition circuit further comprises a second voltage signal acquisition circuit, and an input end of the second voltage signal acquisition circuit is connected with the rectification circuit;
the voltage follower also comprises a second voltage follower, and the input end of the second voltage follower is connected with the output end of the second voltage signal acquisition circuit;
the optical coupler further comprises a second optical coupler, the anode of a second light-emitting diode in the second optical coupler is connected with the output end of the second voltage signal acquisition circuit, and the cathode of the second light-emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a second photosensitive semiconductor tube in the second optocoupler is connected with a power supply through a resistor, an emitter of the second photosensitive semiconductor tube is grounded, and the second light-emitting diode is cut off when the direct-current voltage is lower than an undervoltage threshold value;
the control module further comprises a second control module, wherein the input end of the second control module is connected with the collector of the second photosensitive semiconductor tube, and the output end of the second control module is connected with a control end connecting block of a controllable switch, and the second control module is used for controlling the controllable switch to be turned off when the second light emitting diode is turned off.
Preferably, the second voltage signal acquisition circuit includes a third resistor and a fourth resistor, a first end of the third resistor is used as an input end of the voltage signal acquisition circuit and connected to an output positive line of the rectifier circuit, a second end of the third resistor is connected to a first end of the fourth resistor, a common end of the third resistor is used as an output end of the second voltage signal acquisition circuit, and a second end of the fourth resistor is connected to an output negative line of the rectifier circuit.
Preferably, the controllable switch is a relay, a normally closed contact of the relay is arranged on a live wire between the alternating current power supply and the load, a normally open contact of the relay is suspended, a first end of a coil of the relay serves as a control end of the controllable switch, and a second end of the coil of the relay is connected with the power supply.
Preferably, the first control module includes a first control chip, a first current-limiting resistor, a first NPN type triode, and a first diode, an input end of the first control chip is used as an input end of the first control module, an output end of the first control chip is connected to a base of the first NPN type triode through the first current-limiting resistor, a collector of the first NPN type triode is connected to a cathode of the first diode, an anode of the first diode is used as an output end of the first control module, and an emitter of the first NPN type triode is grounded; the first control chip outputs high level when the first light emitting diode is conducted.
Preferably, the first control module includes a first PNP type triode, a first current-limiting resistor, a first NPN type triode, and a first diode, a base of the first PNP type triode is used as an input terminal of the first control module, a collector of the first PNP type triode is connected to the base of the first NPN type triode through the first current-limiting resistor, an emitter of the first PNP type triode is connected to the power supply, a collector of the first NPN type triode is connected to a cathode of the first diode, an anode of the first diode is used as an output terminal of the first control module, and an emitter of the first NPN type triode is grounded.
Preferably, the second control module includes a second control chip, a second current-limiting resistor, a second NPN type triode, and a second diode, an input end of the second control chip is used as an input end of the second control module, an output end of the second control chip is connected to a base of the second NPN type triode through the second current-limiting resistor, a collector of the second NPN type triode is connected to a cathode of the second diode, an anode of the second diode is used as an output end of the second control module, and an emitter of the second NPN type triode is grounded; and the second control chip outputs high level when the second light emitting diode is cut off.
Preferably, the second control module includes a second current-limiting resistor, a second NPN type triode, and a second diode, a first end of the second current-limiting resistor is used as an input end of the second control module, a second end of the second current-limiting resistor is connected to a base of the first NPN type triode, a collector of the second NPN type triode is connected to the power supply, a collector of the second NPN type triode is connected to a cathode of the second diode, an anode of the second diode is used as an output end of the second control module, and an emitter of the second NPN type triode is grounded.
The invention provides a voltage protection circuit, which is applied to an alternating current power supply input system, wherein the alternating current power supply input system comprises an alternating current power supply, the alternating current power supply is connected with a load, and the circuit comprises: the input end of the voltage signal acquisition circuit is connected with the rectifying circuit; the input end of the voltage follower is connected with the voltage signal acquisition circuit; the anode of a light emitting diode in the optical coupler is connected with the output end of the voltage follower, and the cathode of the light emitting diode is connected with the output negative wire of the rectifying circuit; the collector of a photosensitive semiconductor tube in the optical coupler is connected with a power supply through a resistor, and the emitter of the photosensitive semiconductor tube is grounded; the control module is used for controlling the controllable switch to be switched off when the direct-current voltage output by the rectifying circuit is not within a preset range; the controllable switch is arranged on an output positive electrode line between the alternating current power supply and the load.
Therefore, the voltage follower and the photoelectric coupler are arranged between the rectifying circuit and the control module, so that the unidirectional transmission of electric signals is realized, the electric isolation between the input end of the voltage follower and the output end of the photoelectric coupler is realized, the output signals have no influence on the input end, and the anti-interference capability is strong.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed in the prior art and the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a voltage protection circuit according to the present invention;
fig. 2 is a schematic diagram of a specific structure of a voltage protection circuit according to the present invention;
fig. 3 is a schematic diagram of another specific structure of the voltage protection circuit according to the present invention.
Detailed Description
The core of the invention is to provide a voltage protection circuit, which realizes the one-way transmission of electric signals, realizes the electrical isolation between the input end of a voltage follower and the output end of a photoelectric coupler, has no influence on the input end by output signals and has strong anti-jamming capability.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a voltage protection circuit applied to an ac power input system, where the ac power input system includes an ac power connected to a load, and the circuit includes:
a rectifier circuit 1 connected to an alternating current power supply;
a voltage signal acquisition circuit 2 with an input end connected with the rectification circuit 1;
the input end of the voltage follower is connected with the voltage signal acquisition circuit 2;
the anode of a light emitting diode in the optical coupler is connected with the output end of the voltage follower, and the cathode of the light emitting diode is connected with the output negative wire of the rectifying circuit 1; the collector of a photosensitive semiconductor tube in the optical coupler is connected with a power supply through a resistor, and the emitter of the photosensitive semiconductor tube is grounded;
the control module 4 is connected with the collector of the photosensitive semiconductor tube at the input end and connected with the control end of the controllable switch 5 at the output end, and is used for controlling the controllable switch 5 to be switched off when the direct-current voltage output by the rectifying circuit 1 is not within a preset range; the controllable switch 5 is arranged in the line between the ac power source and the load.
It should be noted that, in the present application, it is not directly determined whether the ac power output by the ac power supply is overvoltage or undervoltage, but the ac power is converted into a dc voltage through the rectifier circuit 1, and it is indirectly determined whether the dc voltage is within a preset range, so as to determine whether the ac power output by the ac power supply is overvoltage or undervoltage.
Specifically, the voltage signal acquisition circuit 2 acquires the direct-current voltage output by the rectification circuit 1, and converts the direct-current voltage into a low-voltage signal to be transmitted to the voltage follower, the voltage follower transmits the low-voltage signal to the optocoupler in a lossless manner, the low-voltage signal can be switched on or switched off by controlling the light emitting diode in the optocoupler so as to control whether the level of the collector of the photosensitive semiconductor tube in the optocoupler is a low level or a high level, and finally, the control module 4 controls when the controllable switch 5 is switched off according to the high-low level of the collector. Wherein the control of the control module 4 is based on a condition: the controllable switch 5 is controlled to be turned off when the direct current voltage is not within the preset range, and the condition specifically comprises that the controllable switch 5 is controlled to be turned off when the direct current voltage is greater than the overvoltage threshold value and the controllable switch 5 is controlled to be turned off when the direct current voltage is lower than the low-voltage threshold value, so that the alternating current power supply and the load are protected.
In this application, set up isolation module 3 between rectifier circuit 1 and control module, isolation module 3 here includes voltage follower and opto-coupler, and wherein, the voltage follower is the high resistance state to preceding stage circuit, is the low resistance state characteristics to the latter stage circuit to realized playing "isolation" effect to preceding stage circuit. The optical coupler has the advantages of small volume, long service life, no contact, strong anti-interference capability, insulation between output and input and unidirectional signal transmission, and further improves the anti-interference performance of the voltage protection circuit.
The invention provides a voltage protection circuit, which is applied to an alternating current power supply input system, wherein the alternating current power supply input system comprises an alternating current power supply, the alternating current power supply is connected with a load, and the circuit comprises: the input end of the voltage signal acquisition circuit is connected with the rectifying circuit; the input end of the voltage follower is connected with the voltage signal acquisition circuit; the anode of a light emitting diode in the optical coupler is connected with the output end of the voltage follower, and the cathode of the light emitting diode is connected with the output negative wire of the rectifying circuit; the collector of a photosensitive semiconductor tube in the optical coupler is connected with a power supply through a resistor, and the emitter of the photosensitive semiconductor tube is grounded; the control module is used for controlling the controllable switch to be switched off when the direct-current voltage output by the rectifying circuit is not within a preset range; the controllable switch is arranged on an output positive electrode line between the alternating current power supply and the load.
Therefore, the voltage follower and the photoelectric coupler are arranged between the rectifying circuit and the control module, so that the unidirectional transmission of electric signals is realized, the electric isolation between the input end of the voltage follower and the output end of the photoelectric coupler is realized, the output signals have no influence on the input end, and the anti-interference capability is strong.
Referring to fig. 2 and fig. 3, wherein fig. 2 is a schematic diagram of a specific structure of a voltage protection circuit provided by the present invention, and fig. 3 is a schematic diagram of a specific structure of another voltage protection circuit provided by the present invention, the circuit is based on the above embodiments:
as a preferred embodiment, the voltage signal acquisition circuit 2 includes a first voltage signal acquisition circuit 21, and an input end of the first voltage signal acquisition circuit 21 is connected to the rectifier circuit 1;
the voltage follower comprises a first voltage follower U1, and the input end of the first voltage follower U1 is connected with the output end of the first voltage signal acquisition circuit 21;
the optical coupler comprises a first optical coupler B1, the anode of a first light emitting diode in the first optical coupler B1 is connected with the output end of the first voltage signal acquisition circuit 21, and the cathode of the first light emitting diode is connected with the output negative wire of the rectifying circuit 1; a collector of a first photosensitive semiconductor tube in the first optocoupler B1 is connected with a power supply through a resistor, an emitter of the first photosensitive semiconductor tube is grounded, and a first light emitting diode is conducted when direct-current voltage exceeds an overvoltage threshold;
the control module 4 comprises a first control module 41, wherein an input end of the first control module 41 is connected with a collector of the first photosensitive semiconductor tube, and an output end of the first control module 41 is connected with a control end connecting block of the controllable switch 5, and is used for controlling the controllable switch 5 to be turned off when the first light emitting diode is turned on.
Specifically, the voltage protection circuit provided by the present application includes an overvoltage protection circuit, and the overvoltage protection circuit specifically includes a first voltage signal acquisition circuit 21, a first isolation module 31 (including a first voltage follower U1 and a first optical coupler B1), and a first control module 41, and when a dc voltage is overvoltage, that is, the dc voltage exceeds an overvoltage threshold, the overvoltage protection circuit operates, thereby protecting the power supply and the load.
As a preferred embodiment, the first voltage signal acquisition circuit 21 includes a first resistor R1 and a second resistor R2, a first end of the first resistor R1 is used as an input end of the voltage signal acquisition circuit 2 and is connected to the output positive line of the rectifier circuit 1, a second end of the first resistor R1 is connected to a first end of the second resistor R2, a common end thereof is used as an output end of the first voltage signal acquisition circuit 21, and a second end of the second resistor R2 is connected to the output negative line of the rectifier circuit 1.
Specifically, in the present application, the first voltage signal collecting circuit 21 may be formed by a voltage dividing circuit formed by a first resistor R1 and a second resistor R2, and the voltage dividing circuit divides a direct current voltage into a divided voltage
V + is the voltage on the output positive line, and in a specific setting, it may be set that when V + is greater than or equal to the overvoltage threshold, the first diode D1 is turned on, so as to implement the action of the overvoltage protection circuit when the dc voltage exceeds the overvoltage threshold.
In addition, it should be noted that, in the prior art, a voltage transformer is usually adopted to collect voltage signals, but the working temperature of the voltage transformer is narrow, usually-25 ° -70 °, and the voltage transformer is not suitable for the case where the requirement for the ambient temperature is high, and the volume of the voltage transformer is large, and the voltage transformer is not suitable for the case where the size is limited.
In the voltage acquisition circuit, the voltage acquisition is carried out by adopting the voltage division circuit consisting of the two voltage division resistors, on one hand, the working temperature of the resistors is higher, and the general model can meet the working temperature of-55-110 degrees, and on the other hand, the voltage division circuit has the advantages of few used devices, simple circuit structure, small volume and low cost.
As a preferred embodiment, the voltage signal acquisition circuit 2 further includes a second voltage signal acquisition circuit 22, and an input end of the second voltage signal acquisition circuit 22 is connected to the rectification circuit 1;
the voltage follower further comprises a second voltage follower U2, and the input end of the second voltage follower U2 is connected with the output end of the second voltage signal acquisition circuit 22;
the optical coupler further comprises a second optical coupler B2, the anode of a second light emitting diode in the second optical coupler B2 is connected with the output end of the second voltage signal acquisition circuit 22, and the cathode of the second light emitting diode is connected with the output negative wire of the rectifying circuit 1; a collector of a second photosensitive semiconductor tube in the second optocoupler B2 is connected with a power supply through a resistor, an emitter of the second photosensitive semiconductor tube is grounded, and a second light-emitting diode is cut off when the direct-current voltage is lower than the undervoltage threshold;
the control module 4 further includes a second control module 42, an input end of the second control module 42 is connected to a collector of the second photosensitive semiconductor, and an output end of the second control module 42 is connected to a control end connection block of the controllable switch 5, and is configured to control the controllable switch 5 to turn off when the second light emitting diode is turned off.
Specifically, the voltage protection circuit provided by the present application further includes an under-voltage protection circuit, and the under-voltage protection circuit specifically includes the second voltage signal acquisition circuit 22, the second isolation module 32 (including the second voltage follower U2 and the second optical coupler B2), and the second control module 42, and when the dc voltage is under-voltage, that is, the dc voltage is lower than the under-voltage threshold, the under-voltage protection circuit acts, so as to protect the power supply and the load.
As a preferred embodiment, the second voltage signal acquisition circuit 22 includes a third resistor R3 and a fourth resistor R4, a first end of the third resistor R3 is used as an input end of the voltage signal acquisition circuit 2 and is connected to the output positive line of the rectifier circuit 1, a second end of the third resistor R3 is connected to a first end of the fourth resistor R4, a common end thereof is used as an output end of the second voltage signal acquisition circuit 22, and a second end of the fourth resistor R4 is connected to the output negative line of the rectifier circuit 1.
Specifically, in the present application, the second voltage signal collecting circuit 22 is formed by a voltage dividing circuit formed by a third resistor R3 and a fourth resistor R4, and the voltage dividing circuit divides the direct current voltage into a divided voltage
In a specific setting, when V + is less than or equal to the overvoltage threshold, the second diode D2D2 is turned off, so that the undervoltage protection circuit operates when the dc voltage is lower than the undervoltage threshold.
As a preferred embodiment, the controllable switch 5 is a relay K, a normally closed contact of the relay K is disposed on a live wire between the ac power source and the load, a normally open contact of the relay K is suspended, a first end of a coil of the relay K serves as a control end of the controllable switch 5, and a second end of the coil of the relay K is connected with the power source.
Specifically, the controllable switch 5 may be a relay K, and other types of controllable switches may be used, and the present invention is not particularly limited herein, and is determined according to the actual situation.
As a preferred embodiment, the first control module 41 includes a first control chip, a first current-limiting resistor R5, a first NPN transistor Q1, and a first diode D1, an input terminal of the first control chip serves as an input terminal of the first control module 41, an output terminal of the first control chip is connected to a base of the first NPN transistor Q1 through a first current-limiting resistor R5, a collector of the first NPN transistor Q1 is connected to a cathode of the first diode D1, an anode of the first diode D1 serves as an output terminal of the first control module 41, and an emitter of the first NPN transistor Q1 is grounded; the first control chip outputs high level when the first light emitting diode is conducted.
Specifically, when overvoltage occurs, the first light emitting diode is switched from a cut-off state to a conducting state, the collector and the emitter of the first photosensitive semiconductor tube are conducted, the collector is pulled down by the emitter (the pull-up resistor pulls the collector of the first optocoupler B1 to a high level when the input voltage is not overvoltage), when the first control chip detects that the input pin INA is changed from the high level to the low level, the output pin OUTA is set to the high level, the first NPN type triode Q1 is driven through the first current limiting resistor R5, the first NPN type triode Q1 is conducted, the first diode D1 is conducted, the relay K works, the relay K switches from a normally closed state to a normally open state, the power supply circuit is disconnected, and the function of protecting a subsequent working circuit is achieved.
In a preferred embodiment, the first control module 41 includes a first PNP transistor Q3, a first current limiting resistor R5, a first NPN transistor Q1, and a first diode D1, a base of the first PNP transistor Q3 is used as an input terminal of the first control module 41, a collector of the first PNP transistor Q3 is connected to a base of the first NPN transistor Q1 through a first current limiting resistor R5, an emitter of the first NPN transistor Q3 is connected to a power supply, a collector of the first NPN transistor Q1 is connected to a cathode of the first diode D1, an anode of the first diode D1 is used as an output terminal of the first control module 41, and an emitter of the first NPN transistor Q1 is connected to ground.
Specifically, in this embodiment, the base of the first PNP triode Q3 is used as the input terminal of the first control chip, the collector of the first PNP triode Q3 is used as the output terminal of the first control chip, when the voltage at the base of the first PNP triode Q3 changes from high level to low level, the first PNP triode Q3 changes from off to on, the voltage at the collector of the first PNP triode Q3 changes into high voltage, the first NPN triode Q1 is on, the first diode D1 is on, the relay K operates, the relay K switch changes from normally closed state to normally open state, the power supply line is disconnected, and the function of protecting the subsequent operating circuit is achieved.
As a preferred embodiment, the second control module 42 includes a second control chip, a second current-limiting resistor R6, a second NPN transistor Q2, and a second diode D2, an input terminal of the second control chip serves as an input terminal of the second control module 42, an output terminal of the second control chip is connected to a base of the second NPN transistor Q2 through a second current-limiting resistor R6, a collector of the second NPN transistor Q2 is connected to a cathode of the second diode D2, an anode of the second diode D2 serves as an output terminal of the second control module 42, and an emitter of the second NPN transistor Q2 is grounded; the second control chip outputs high level when the second light emitting diode is cut off.
Specifically, when the voltage is undervoltage, the second light emitting diode in the second optocoupler B2 is switched from a conducting state to an off state, the collector and the emitter of the first photosensitive semiconductor transistor are switched from the conducting state to the off state, the collector outputs a high level due to a pull-up resistor, the second control chip sets the output pin OUTB to a high level after detecting that the input pin INB changes from a low level to a high level, the second NPN type triode Q2 is driven through the second current-limiting resistor R6, the second NPN type triode Q2 is switched on, the second diode D2 is switched on, the relay K works, the switch of the relay K is changed from a normally closed state to a normally open state, the power supply line is disconnected, and the function of protecting a subsequent working circuit is achieved.
In a preferred embodiment, the second control module 42 includes a second current-limiting resistor R6, a second NPN transistor Q2, and a second diode D2, a first end of the second current-limiting resistor R6 serves as an input terminal of the second control module 42, a second end of the second current-limiting resistor R6 is connected to a base of the first NPN transistor Q1, a collector of the second NPN transistor Q2 is connected to the power supply, a collector of the second NPN transistor Q2 is connected to a cathode of the second diode D2, an anode of the second diode D2 serves as an output terminal of the second control module 42, and an emitter of the second NPN transistor Q2 is grounded.
Specifically, in this embodiment, the first end of the second current-limiting resistor R6 is used as the input end of the second control chip, when the voltage of the base of the second NPN transistor Q2 changes from low level to high level, the second NPN transistor Q2 changes from off to on, the emitter of the second NPN transistor Q2 changes to high voltage, the second NPN transistor Q2 is on, the second diode D2 is on, the relay K operates, the relay K switch changes from a normally closed state to a normally open state, and the power line is disconnected, so as to protect the subsequent operating circuit.
In addition, both the first control module 41 and the second control module 42 may have other logic structures, and the present invention is not limited thereto.
In conclusion, the voltage protection circuit provided by the application has the advantages of low cost, small size and wider range of used ambient temperature on the basis of strong anti-interference capability.
It is to be noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. A voltage protection circuit is applied to an alternating current power supply input system, the alternating current power supply input system comprises an alternating current power supply, the alternating current power supply is connected with a load, and the voltage protection circuit is characterized by comprising:
a rectifying circuit connected to the AC power supply;
the input end of the voltage signal acquisition circuit is connected with the rectifying circuit;
the input end of the voltage follower is connected with the voltage signal acquisition circuit;
the anode of a light emitting diode in the optical coupler is connected with the output end of the voltage follower, and the cathode of the light emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a photosensitive semiconductor tube in the optocoupler is connected with a power supply through a resistor, and an emitter of the photosensitive semiconductor tube is grounded;
the control module is used for controlling the controllable switch to be switched off when the direct-current voltage output by the rectifying circuit is not within a preset range; the controllable switch is arranged on a live wire between the alternating current power supply and a load;
the voltage signal acquisition circuit comprises a first voltage signal acquisition circuit, and the input end of the first voltage signal acquisition circuit is connected with the rectification circuit;
the voltage follower comprises a first voltage follower, and the input end of the first voltage follower is connected with the output end of the first voltage signal acquisition circuit;
the optical coupler comprises a first optical coupler, the anode of a first light emitting diode in the first optical coupler is connected with the output end of the first voltage follower, and the cathode of the first light emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a first photosensitive semiconductor tube in the first optocoupler is connected with a power supply through a resistor, an emitter of the first photosensitive semiconductor tube is grounded, and the first light-emitting diode is conducted when the direct-current voltage exceeds an overvoltage threshold;
the control module comprises a first control module, the input end of the first control module is connected with the collector of the first photosensitive semiconductor tube, and the output end of the first control module is connected with a control end connecting block of a controllable switch, and the first control module is used for controlling the controllable switch to be switched off when the first light-emitting diode is switched on;
the voltage signal acquisition circuit also comprises a second voltage signal acquisition circuit, and the input end of the second voltage signal acquisition circuit is connected with the rectification circuit;
the voltage follower also comprises a second voltage follower, and the input end of the second voltage follower is connected with the output end of the second voltage signal acquisition circuit;
the optical coupler further comprises a second optical coupler, the anode of a second light-emitting diode in the second optical coupler is connected with the output end of the second voltage follower, and the cathode of the second light-emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a second photosensitive semiconductor tube in the second optocoupler is connected with a power supply through a resistor, an emitter of the second photosensitive semiconductor tube is grounded, and the second light-emitting diode is cut off when the direct-current voltage is lower than an undervoltage threshold value;
the control module further comprises a second control module, wherein the input end of the second control module is connected with the collector of the second photosensitive semiconductor tube, and the output end of the second control module is connected with a control end connecting block of a controllable switch, and the second control module is used for controlling the controllable switch to be turned off when the second light-emitting diode is turned off;
the first control module comprises a first control chip, a first current-limiting resistor, a first NPN type triode and a first diode, wherein the input end of the first control chip is used as the input end of the first control module, the output end of the first control chip is connected with the base electrode of the first NPN type triode through the first current-limiting resistor, the collector electrode of the first NPN type triode is connected with the cathode of the first diode, the anode of the first diode is used as the output end of the first control module, and the emitter electrode of the first NPN type triode is grounded; the first control chip outputs high level when the first light emitting diode is conducted;
the second control module comprises a second control chip, a second current-limiting resistor, a second NPN triode and a second diode, wherein the input end of the second control chip is used as the input end of the second control module, the output end of the second control chip is connected with the base electrode of the second NPN triode through the second current-limiting resistor, the collector electrode of the second NPN triode is connected with the cathode of the second diode, the anode of the second diode is used as the output end of the second control module, and the emitter electrode of the second NPN triode is grounded; and the second control chip outputs high level when the second light emitting diode is cut off.
2. The voltage protection circuit of claim 1, wherein the first voltage signal acquisition circuit comprises a first resistor and a second resistor, a first end of the first resistor is connected to an output positive line of the rectifier circuit as an input terminal of the voltage signal acquisition circuit, a second end of the first resistor is connected to a first end of the second resistor, a common terminal of the first resistor is an output terminal of the first voltage signal acquisition circuit, and a second end of the second resistor is connected to an output negative line of the rectifier circuit.
3. The voltage protection circuit according to claim 2, wherein the second voltage signal acquisition circuit includes a third resistor and a fourth resistor, a first terminal of the third resistor is connected to the output positive line of the rectifier circuit as the input terminal of the voltage signal acquisition circuit, a second terminal of the third resistor is connected to a first terminal of the fourth resistor, a common terminal thereof is used as the output terminal of the second voltage signal acquisition circuit, and a second terminal of the fourth resistor is connected to the output negative line of the rectifier circuit.
4. The voltage protection circuit of claim 1, wherein the controllable switch is a relay, the normally closed contact of the relay is disposed in a hot line between the ac power source and the load, the normally open contact of the relay is floating, the first end of the coil of the relay serves as the control end of the controllable switch, and the second end of the coil of the relay is connected to the power source.
5. A voltage protection circuit is applied to an alternating current power supply input system, the alternating current power supply input system comprises an alternating current power supply, the alternating current power supply is connected with a load, and the voltage protection circuit is characterized by comprising:
a rectifying circuit connected to the AC power supply;
the input end of the voltage signal acquisition circuit is connected with the rectifying circuit;
the input end of the voltage follower is connected with the voltage signal acquisition circuit;
the anode of a light emitting diode in the optical coupler is connected with the output end of the voltage follower, and the cathode of the light emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a photosensitive semiconductor tube in the optocoupler is connected with a power supply through a resistor, and an emitter of the photosensitive semiconductor tube is grounded;
the control module is used for controlling the controllable switch to be switched off when the direct-current voltage output by the rectifying circuit is not within a preset range; the controllable switch is arranged on a live wire between the alternating current power supply and a load;
the voltage signal acquisition circuit comprises a first voltage signal acquisition circuit, and the input end of the first voltage signal acquisition circuit is connected with the rectification circuit;
the voltage follower comprises a first voltage follower, and the input end of the first voltage follower is connected with the output end of the first voltage signal acquisition circuit;
the optical coupler comprises a first optical coupler, the anode of a first light emitting diode in the first optical coupler is connected with the output end of the first voltage follower, and the cathode of the first light emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a first photosensitive semiconductor tube in the first optocoupler is connected with a power supply through a resistor, an emitter of the first photosensitive semiconductor tube is grounded, and the first light-emitting diode is conducted when the direct-current voltage exceeds an overvoltage threshold;
the control module comprises a first control module, the input end of the first control module is connected with the collector of the first photosensitive semiconductor tube, and the output end of the first control module is connected with a control end connecting block of a controllable switch, and the first control module is used for controlling the controllable switch to be switched off when the first light-emitting diode is switched on;
the voltage signal acquisition circuit also comprises a second voltage signal acquisition circuit, and the input end of the second voltage signal acquisition circuit is connected with the rectification circuit;
the voltage follower also comprises a second voltage follower, and the input end of the second voltage follower is connected with the output end of the second voltage signal acquisition circuit;
the optical coupler further comprises a second optical coupler, the anode of a second light-emitting diode in the second optical coupler is connected with the output end of the second voltage follower, and the cathode of the second light-emitting diode is connected with the output negative wire of the rectifying circuit; a collector of a second photosensitive semiconductor tube in the second optocoupler is connected with a power supply through a resistor, an emitter of the second photosensitive semiconductor tube is grounded, and the second light-emitting diode is cut off when the direct-current voltage is lower than an undervoltage threshold value;
the control module further comprises a second control module, wherein the input end of the second control module is connected with the collector of the second photosensitive semiconductor tube, and the output end of the second control module is connected with a control end connecting block of a controllable switch, and the second control module is used for controlling the controllable switch to be turned off when the second light-emitting diode is turned off;
the first control module comprises a first PNP type triode, a first current-limiting resistor, a first NPN type triode and a first diode, wherein the base electrode of the first PNP type triode is used as the input end of the first control module, the collector electrode of the first PNP type triode is connected with the base electrode of the first NPN type triode through the first current-limiting resistor, the emitter electrode of the first PNP type triode is connected with a power supply, the collector electrode of the first NPN type triode is connected with the cathode of the first diode, the anode of the first diode is used as the output end of the first control module, and the emitter electrode of the first NPN type triode is grounded;
the second control module comprises a second current-limiting resistor, a second NPN type triode and a second diode, wherein the first end of the second current-limiting resistor is used as the input end of the second control module, the second end of the second current-limiting resistor is connected with the base electrode of the first NPN type triode, the collector electrode of the second NPN type triode is connected with a power supply, the collector electrode of the second NPN type triode is connected with the cathode of the second diode, the anode of the second diode is used as the output end of the second control module, and the emitter electrode of the second NPN type triode is grounded.
6. The voltage protection circuit according to claim 5, wherein the first voltage signal acquisition circuit includes a first resistor and a second resistor, a first end of the first resistor is connected to an output positive line of the rectifier circuit as an input terminal of the voltage signal acquisition circuit, a second end of the first resistor is connected to a first end of the second resistor, a common terminal thereof is an output terminal of the first voltage signal acquisition circuit, and a second end of the second resistor is connected to an output negative line of the rectifier circuit.
7. The voltage protection circuit according to claim 6, wherein the second voltage signal acquisition circuit includes a third resistor and a fourth resistor, a first end of the third resistor is connected to the output positive line of the rectifier circuit as the input terminal of the voltage signal acquisition circuit, a second end of the third resistor is connected to a first end of the fourth resistor, a common terminal thereof is used as the output terminal of the second voltage signal acquisition circuit, and a second end of the fourth resistor is connected to the output negative line of the rectifier circuit.
8. The voltage protection circuit of claim 5, wherein the controllable switch is a relay, the normally closed contact of the relay is disposed in a hot line between the AC power source and a load, the normally open contact of the relay is floating, the first end of the coil of the relay serves as the control end of the controllable switch, and the second end of the coil of the relay is connected to the power source.
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| DE102018113145B4 (en) * | 2018-06-01 | 2020-06-04 | Infineon Technologies Ag | RECTIFIER DEVICE |
| CN108900104B (en) * | 2018-09-10 | 2024-04-16 | 深圳市德利和能源技术有限公司 | IGBT analog device, level analog circuit and three-level simulation platform |
| CN110086147B (en) * | 2019-05-29 | 2020-07-24 | 珠海格力电器股份有限公司 | Protection circuit, drive plate and electrical equipment |
| CN111174390A (en) * | 2020-02-17 | 2020-05-19 | 珠海格力电器股份有限公司 | Power taking circuit, wire controller, air conditioner and resistance control method |
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