CN112600161B - Silicon controlled rectifier high temperature protection device and circuit control system - Google Patents
Silicon controlled rectifier high temperature protection device and circuit control system Download PDFInfo
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- CN112600161B CN112600161B CN202011596101.1A CN202011596101A CN112600161B CN 112600161 B CN112600161 B CN 112600161B CN 202011596101 A CN202011596101 A CN 202011596101A CN 112600161 B CN112600161 B CN 112600161B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
- H02H5/042—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature using temperature dependent resistors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/20—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for electronic equipment
- H02H7/205—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for electronic equipment for controlled semi-conductors which are not included in a specific circuit arrangement
Abstract
The embodiment of the invention discloses a silicon controlled rectifier high-temperature protection device, which is arranged between a control unit and a silicon controlled rectifier unit, and comprises: the first end of the resistance variable unit is connected to a power supply, and the resistance of the resistance variable unit changes along with the temperature change of the silicon controlled rectifier unit; the triode unit is respectively connected to the trigger circuit passage, the second end of the resistance variable unit and the ground end; when the temperature of the controllable silicon unit is higher than a preset temperature threshold, the resistance of the resistance variable unit is changed, so that the triode unit is conducted, and the trigger circuit passage is conducted with the ground terminal. Compared with the traditional method, the high-temperature protection device for the silicon controlled rectifier realizes high-temperature protection of the silicon controlled rectifier from a circuit level, has higher reliability, and improves the safety and stability of loads or products controlled by the silicon controlled rectifier.
Description
Technical Field
The invention relates to the technical field of electronic circuits, in particular to a silicon controlled rectifier high-temperature protection device and a circuit control system.
Background
The silicon controlled rectifier (Silicon Controlled Rectifier) is a high-power electrical element, also called a thyristor. It has the advantages of small volume, high efficiency, long service life, etc. In an automatic control system, the device can be used as a high-power driving device to control high-power equipment by using a low-power control. Some small household appliances using thyristors are common in household appliances, such as health preserving kettles, electric stewing cups and the like. Most of the products are used for controlling loads by the silicon controlled rectifier, such as when the silicon controlled rectifier is turned on by using a singlechip to control the on-off of the silicon controlled rectifier through a trigger circuit, the silicon controlled rectifier generates more heat by itself due to long-time work, the temperature of the silicon controlled rectifier is increased along with the increase of the self heating value, and the silicon controlled rectifier is out of control even burnt out, the shell of the fuse machine is burnt out and fire occurs due to the fact that the temperature of the silicon controlled rectifier is too high.
The invention patent number CN201110117029.4 discloses an LED dimming driving circuit, which has the technical idea that when the temperature of an LED lamp is higher than a preset value, the resistance value of a negative temperature coefficient thermistor RT1 is reduced, the voltage of a control pin PB1 of a singlechip U1 is increased, the output pulse width of an output pin PB3 is changed by the singlechip according to the change of PB1, and the current flowing through the LED is reduced. However, the overheat protection circuit of the comparison document needs to carry out complex programming on the singlechip, is easy to fail, has low reliability, and cannot carry out high-temperature protection on the silicon controlled rectifier from the circuit layer.
It is seen that there is a need to provide a technique for high temperature protection of a thyristor from a circuit layer based on circuit design.
Disclosure of Invention
Compared with the scheme of programming a singlechip in the traditional method, the high-temperature protection device realizes high-temperature protection of the thyristor from a circuit level and has higher reliability, so that the problem of possible singlechip faults caused by singlechip programming control is effectively avoided, the thyristor is further subjected to high-efficiency and reliable high-temperature protection, and the safety and stability of loads or products controlled by the thyristor are improved.
In order to solve the above technical problem, a first aspect of the present invention discloses a thyristor high temperature protection device, which is disposed between a control unit and a thyristor unit, the device comprising:
the first end of the resistance variable unit is connected to a power supply, and the resistance of the resistance variable unit changes along with the temperature change of the silicon controlled rectifier unit;
the triode unit is respectively connected to the trigger circuit passage, the second end of the resistance variable unit and the ground end; the trigger circuit path is a connection circuit path between a control signal output end of the control unit and a control signal input end of a trigger circuit for driving the thyristor unit;
when the temperature of the controllable silicon unit is higher than a preset temperature threshold, the resistance of the resistance variable unit is changed, so that the triode unit is conducted, and the trigger circuit passage is conducted with the ground terminal.
In an optional implementation manner, in the first aspect of the present invention, the resistance of the resistance variable unit is in a negative correlation with the temperature of the thyristor unit, when the temperature of the thyristor unit is higher than the temperature threshold, the resistance of the resistance variable unit is lower than the resistance threshold, and when the resistance of the resistance variable unit is lower than the resistance threshold, the triode unit is turned on, so that the trigger circuit path is turned on with the ground terminal.
In an alternative embodiment, in the first aspect of the present invention, the transistor unit is an NPN transistor, a base of the transistor unit is connected to the second terminal of the resistance variable unit, an emitter of the transistor unit is connected to the ground terminal, and a collector of the transistor unit is connected to the trigger circuit path.
As an alternative embodiment, in the first aspect of the present invention, the resistance variable unit is a thermistor with a negative temperature coefficient, and/or the resistance variable unit is disposed close to the thyristor unit, so that the resistance of the resistance variable unit may vary with the temperature of the thyristor unit.
In an optional implementation manner, in the first aspect of the present invention, a first current limiting resistor is further disposed between the second end of the resistance variable unit and the base of the triode unit.
As an alternative implementation manner, in the first aspect of the present invention, the trigger circuit of the thyristor unit includes a triac unit, a base electrode of the triac unit is connected to a control signal output terminal of the control unit, an emitter electrode of the triac unit is grounded, and a collector electrode of the triac unit is connected to a trigger terminal of the thyristor unit.
In an optional implementation manner, in the first aspect of the present invention, a second current limiting resistor is further disposed between the base of the triac and the control signal output end of the singlechip, and/or a current limiting resistor unit is further disposed between the collector of the trigger triode and the trigger end of the thyristor.
As an optional implementation manner, in the first aspect of the present invention, the current limiting resistor unit includes a third current limiting resistor and a fourth current limiting resistor that are disposed in parallel.
As an optional implementation manner, in the first aspect of the present invention, a clamping resistor is further disposed between the base and the emitter of the triac.
The second aspect of the invention discloses a thyristor circuit control system, the system comprises a control unit, a thyristor unit and a thyristor high temperature protection device, the device is arranged between the control unit and the thyristor unit, the device comprises:
the first end of the resistance variable unit is connected to a power supply, and the resistance of the resistance variable unit changes along with the temperature change of the silicon controlled rectifier unit;
the triode unit is respectively connected to the trigger circuit passage, the second end of the resistance variable unit and the ground end; the trigger circuit path is a connection circuit path between a control signal output end of the control unit and a control signal input end of a trigger circuit for driving the thyristor unit;
when the temperature of the controllable silicon unit is higher than a preset temperature threshold, the resistance of the resistance variable unit is changed, so that the triode unit is conducted, and the trigger circuit passage is conducted with the ground terminal.
In a second aspect of the present invention, the resistance of the resistance variable unit is in a negative correlation with the temperature of the thyristor unit, when the temperature of the thyristor unit is higher than a temperature threshold, the resistance of the resistance variable unit is lower than a resistance threshold, and when the resistance of the resistance variable unit is lower than the resistance threshold, the triode unit is turned on, so that the trigger circuit path is turned on with the ground terminal.
In a second aspect of the present invention, the transistor unit is an NPN transistor, a base of the transistor unit is connected to the second terminal of the resistance variable unit, an emitter of the transistor unit is connected to the ground terminal, and a collector of the transistor unit is connected to the trigger circuit path.
As an alternative embodiment, in the second aspect of the present invention, the resistance variable unit is a thermistor with a negative temperature coefficient, and/or the resistance variable unit is disposed close to the thyristor unit, so that the resistance of the resistance variable unit may vary with the temperature of the thyristor unit.
In a second aspect of the present invention, as an alternative implementation manner, a first current limiting resistor is further disposed between the second end of the resistance variable unit and the base of the triode unit.
As an alternative embodiment, in the second aspect of the present invention, the trigger circuit of the thyristor unit includes a triac unit, a base of the triac unit is connected to a control signal output terminal of the control unit, an emitter of the triac unit is grounded, and a collector of the triac unit is connected to a trigger terminal of the thyristor unit.
In a second aspect of the present invention, a second current limiting resistor is further disposed between the base of the triac and the control signal output end of the singlechip, and/or a current limiting resistor unit is further disposed between the collector of the trigger triode and the trigger end of the thyristor.
As an alternative embodiment, in the second aspect of the present invention, the current limiting resistor unit includes a third current limiting resistor and a fourth current limiting resistor disposed in parallel.
As an alternative embodiment, in the second aspect of the present invention, a clamping resistor is further disposed between the base and the emitter of the triac.
Compared with the prior art, the invention has the following beneficial effects:
the embodiment of the invention discloses a silicon controlled rectifier high-temperature protection device, which is arranged between a control unit and a silicon controlled rectifier unit, and comprises: the first end of the resistance variable unit is connected to a power supply, and the resistance of the resistance variable unit changes along with the temperature change of the silicon controlled rectifier unit; the triode unit is respectively connected to the trigger circuit passage, the second end of the resistance variable unit and the ground end; the trigger circuit path is a connection circuit path between a control signal output end of the control unit and a control signal input end of a trigger circuit for driving the thyristor unit; when the temperature of the controllable silicon unit is higher than a preset temperature threshold, the resistance of the resistance variable unit is changed, so that the triode unit is conducted, and the trigger circuit passage is conducted with the ground terminal. Therefore, compared with the scheme of programming the singlechip in the traditional method, the high-temperature protection device for the silicon controlled rectifier has the advantages that the high-temperature protection device for the silicon controlled rectifier is high in reliability from a circuit level, so that the problem of faults of the singlechip possibly caused by programming control of the singlechip is effectively avoided, the high-temperature protection is effectively and reliably carried out on the silicon controlled rectifier, and the safety and stability of loads or products controlled by the silicon controlled rectifier are improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a functional module of a SCR high temperature protection device according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a functional module of another SCR high temperature protection device according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a design of the resistance variable unit 101 approaching the thyristor unit 20 according to the embodiment of the present invention;
fig. 4 is a schematic circuit design diagram of a scr high temperature protection device according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terms first, second and the like in the description and in the claims and in the above-described figures are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, apparatus, article, or article that comprises a list of steps or elements is not limited to only those listed but may optionally include other steps or elements not listed or inherent to such process, method, article, or article.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
Compared with the scheme of programming a singlechip in the traditional method, the high-temperature protection device realizes high-temperature protection of the thyristor from the circuit level and has higher reliability, so that the problem of possible singlechip faults caused by singlechip programming control is effectively avoided, the thyristor is further subjected to high-efficiency and reliable high-temperature protection, and the safety and stability of loads or products controlled by the thyristor are improved. The following will describe in detail.
Example 1
Referring to fig. 1, fig. 1 is a schematic diagram of a functional module of a scr high temperature protection device according to an embodiment of the present invention. As shown in fig. 1, the scr high temperature protection device is disposed between a control unit 10 and a thyristor unit 20, and the device includes a resistance variable unit 101 and a triode unit 102, wherein a first end of the resistance variable unit 101 is connected to a power source, and a resistance of the resistance variable unit 101 varies with a temperature variation of the thyristor unit 20.
Specifically, the triode unit 102 is connected to the trigger circuit path, the second terminal of the resistance variable unit 101, and the ground terminal, respectively. Wherein the trigger circuit path is a connection circuit path between the control signal output terminal Out of the control unit 10 and the control signal input terminal In of the trigger circuit 30 for driving the thyristor unit 20.
Specifically, the resistance variable unit 101 and the transistor unit 102 are set to: when the temperature of the thyristor unit 20 is higher than the preset temperature threshold, the resistance of the resistance variable unit 101 is changed, so that the triode unit 102 is turned on, and the trigger circuit is turned on with the ground terminal. At this time, since the trigger circuit path is conducted with the ground terminal, the control signal, such as a high level signal, output by the control unit 101 through the control signal output terminal Out will be directed to the ground terminal through the trigger circuit path conducted with the ground terminal, and the trigger circuit 30 will not be triggered at this time, so that the thyristor unit 20 stops working, thereby playing a role in protecting the thyristor unit 20 at high temperature.
Alternatively, the control unit 10 may be a single-chip microcomputer with an IO control function. Alternatively, the thyristor unit 20 may be used to control the load in other circuits, the trigger terminal of which is connected to the control unit 10 through the trigger circuit 30, and the anode and cathode of which are normally connected to the switching circuit of the load, so as to control the load.
Specifically, the above-mentioned settings of the resistance variable unit 101 and the triode unit 102 can be implemented by an operator by adjusting parameters and setting modes of electronic components, and any circuit design that can implement the above-mentioned settings should be considered as falling within the protection scope of the present invention.
Therefore, compared with the scheme of programming the singlechip in the traditional method, the high-temperature protection device realizes high-temperature protection of the silicon controlled rectifier from the circuit level, has higher reliability, effectively avoids the problem of single-chip microcomputer faults possibly caused by single-chip microcomputer programming control, and further carries out high-efficiency and reliable high-temperature protection on the silicon controlled rectifier, and improves the safety and stability of loads or products controlled by the silicon controlled rectifier.
As an alternative implementation manner, in the embodiment of the present invention, the resistance of the resistance variable unit 101 and the temperature of the thyristor unit 20 are in a negative correlation, when the temperature of the thyristor unit 20 is higher than the temperature threshold, the resistance of the resistance variable unit 101 is lower than the resistance threshold, and when the resistance of the resistance variable unit 101 is lower than the resistance threshold, the triode unit 102 is turned on, so that the trigger circuit path is turned on with the ground terminal.
Alternatively, the resistance variable unit 101 is a negative temperature coefficient thermistor NTC.
As an alternative implementation, in the embodiment of the present invention, as shown in fig. 2, the transistor unit 102 is an NPN transistor, the base b1 of the transistor unit 102 is connected to the second terminal of the resistance variable unit 101, the emitter e1 of the transistor unit 102 is connected to the ground terminal, and the collector c1 of the transistor unit 102 is connected to the trigger circuit path.
By setting the resistance variable unit 101 in this way, that is, when the temperature of the thyristor unit 20 increases, the resistance of the NTC decreases accordingly, then the voltage between the base b1 and the emitter e1 of the triode unit 102 (which is an NPN type triode) increases gradually, and when the resistance of the resistance variable unit 101 decreases to a certain resistance threshold, the voltage between the base b1 and the emitter e1 of the triode unit 102 reaches the turn-on voltage of the triode unit 102, and at this time, the collector c1 and the emitter e1 of the triode unit 102 are turned on, so that the trigger circuit path is turned on with the ground, thereby realizing the function of high temperature protection.
As an optional implementation manner, in this embodiment of the present invention, a first current limiting resistor 401 is further disposed between the second end of the resistance variable unit 101 and the base b1 of the triode unit 102, so as to limit the magnitude of the current of the branch circuit, so as to prevent the components connected in series from being burned out due to excessive current. Alternatively, the operator may also adjust the current-voltage relationship between the resistance variable unit 101 and the triode unit 102 by setting the size of the first current limiting resistor 401 to implement the above-mentioned setting of the resistance threshold and the temperature threshold in the high temperature protection. For example, the operator may determine the appropriate first current limiting resistor 401 according to the temperature-resistance variation relationship between the resistance variable unit 101 and the thyristor unit 20, the voltage relationship between the power supply and the ground, and the on voltage of the triode unit 102.
As an alternative implementation, in the embodiment of the present invention, the trigger circuit 30 of the triac unit 20 includes a triac unit 301, a base b2 of the triac unit 301 is connected to the control signal output Out of the control unit 10, an emitter e2 of the triac unit 301 is grounded, and a collector c2 of the triac unit 301 is connected to the trigger terminal of the triac unit 20.
In this alternative embodiment, the thyristor unit 20 is a bidirectional thyristor or a common thyristor, the triac unit 301 is an NPN type triode, and the triac unit 301 is configured to trigger a trigger terminal of the thyristor unit 20 to trigger the thyristor unit 20 when receiving a control signal.
As an optional implementation manner, in the embodiment of the present invention, a second current limiting resistor 402 is further disposed between the base b2 of the triac 301 and the control signal output terminal Out of the singlechip, so as to limit the magnitude of the current of the branch, so as to prevent the components connected in series from being burned Out due to excessive current.
As an alternative implementation manner, in the embodiment of the present invention, a current limiting resistor unit is further disposed between the collector c1 of the trigger transistor unit 301 and the trigger terminal of the thyristor unit 20. Optionally, in the embodiment of the present invention, the current limiting resistor unit includes a third current limiting resistor 403 and a fourth current limiting resistor 404 that are disposed in parallel, so as to limit the magnitude of the current of the branch circuit, so as to prevent the components connected in series from being burned out due to excessive current.
As an alternative implementation, in this embodiment of the present invention, a clamp resistor 405 is further disposed between the base b2 and the emitter e2 of the triac 301, so as to limit the voltage between the base b2 and the emitter e2 of the triac 301, so as to ensure the stability of the triode circuit.
As an alternative implementation, in the embodiment of the present invention, the resistance variable unit 101 is disposed near the thyristor unit 20, so that the resistance of the resistance variable unit 101 may vary with the temperature of the thyristor unit 20. Specifically, when the PCB board design is performed, the resistance variable unit 101 is disposed near the thyristor unit 20, an example is given in fig. 3, and referring to this example, a person skilled in the art can understand how to implement the technical details of disposing the resistance variable unit 101 near the thyristor unit 20 in this embodiment.
Next, taking fig. 4 as an example, a specific circuit design example is also disclosed in the embodiment of the present invention. As shown in fig. 4, in the circuit design example, the resistors R1, R2, R3, R4 and the transistor Q1 form a trigger circuit, wherein the resistors R1, R2, R3 are current limiting, the resistor R4 is a clamping function, the transistor Q1 is a switching function, and the gate (trigger terminal) of the thyristor T1 is triggered to turn on or off the thyristor T1. The negative temperature coefficient thermistor RT, the resistor R5 and the triode Q2 form a silicon controlled high temperature protection circuit, wherein the negative temperature coefficient thermistor RT has the characteristics that: when the temperature increases and the resistance decreases, the resistor R5 acts as a current limiter and the transistor Q2 acts as a switch.
The working principle of the circuit design is explained in detail as follows:
when the silicon controlled rectifier T1 is at low temperature, the negative temperature coefficient thermistor RT is in a high resistance state, and a singlechip IO port signal flows to the b pole of the triode Q1 through the current limiting resistor R3, so that the ce pole of the triode Q1 is conducted, the silicon controlled rectifier T1 is conducted, and when the silicon controlled rectifier T1 is conducted, the silicon controlled rectifier self can generate heat due to the connection of a load. The heat of the thyristor is transferred to the thermistor RT, and the resistance of RT is reduced while the heat is transferred.
When the heat of the silicon controlled rectifier is accumulated to a certain high temperature, the heat rises to reach a preset parameter value range, and meanwhile, the resistance of RT also falls to reach the preset parameter value range, at the moment, RT is in a low resistance state, which is equivalent to that the voltage and the current of the power VCC are conducted to the b pole of the triode Q2 through the current limiting resistor R5, the ce pole of the triode Q2 is conducted, and because of the conduction of the triode Q2, the signal of the IO port of the singlechip is not conducted to the b pole of the triode Q1 any more after passing through the current limiting resistor R3, and flows into the ground GND through the ce pole of the triode Q2. Because the driving information of the b pole of the triode Q1 disappears, the triode Q1 is turned off, so that the silicon controlled rectifier T1 is turned off and does not work, namely, heat generation is stopped.
When the thyristor T1 stops heating and is cooled, the operation is conducted again, namely the process is repeatedly executed.
Example two
The embodiment of the invention discloses a silicon controlled rectifier circuit control system, the structure of which can be referred to as figure 1, and the system comprises a control unit 10, a silicon controlled rectifier unit 20 and a silicon controlled rectifier high temperature protection device. The thyristor high temperature protection device is disposed between the control unit 10 and the thyristor unit 20, and comprises a resistance variable unit 101 and a triode unit 102, wherein a first end of the resistance variable unit 101 is connected to a power supply, and the resistance of the resistance variable unit 101 changes along with the temperature change of the thyristor unit 20.
Specifically, the triode unit 102 is connected to the trigger circuit path, the second terminal of the resistance variable unit 101, and the ground terminal, respectively. Wherein the trigger circuit path is a connection circuit path between the control signal output terminal Out of the control unit 10 and the control signal input terminal In of the trigger circuit 30 for driving the thyristor unit 20.
Specifically, the resistance variable unit 101 and the transistor unit 102 are set to: when the temperature of the thyristor unit 20 is higher than the preset temperature threshold, the resistance of the resistance variable unit 101 is changed, so that the triode unit 102 is turned on, and the trigger circuit is turned on with the ground terminal. At this time, since the trigger circuit path is conducted with the ground terminal, the control signal, such as a high level signal, output by the control unit 101 through the control signal output terminal Out will be directed to the ground terminal through the trigger circuit path conducted with the ground terminal, and the trigger circuit 30 will not be triggered at this time, so that the thyristor unit 20 stops working, thereby playing a role in protecting the thyristor unit 20 at high temperature.
Alternatively, the control unit 10 may be a single-chip microcomputer with an IO control function. Alternatively, the thyristor unit 20 may be used to control the load in other circuits, the trigger terminal of which is connected to the control unit 10 through the trigger circuit 30, and the anode and cathode of which are normally connected to the switching circuit of the load, so as to control the load.
Specifically, the above-mentioned settings of the resistance variable unit 101 and the triode unit 102 can be implemented by an operator by adjusting parameters and setting modes of electronic components, and any circuit design that can implement the above-mentioned settings should be considered as falling within the protection scope of the present invention.
Therefore, compared with the scheme of programming the singlechip in the traditional method, the high-temperature protection device realizes high-temperature protection of the silicon controlled rectifier from the circuit level, has higher reliability, effectively avoids the problem of single-chip microcomputer faults possibly caused by single-chip microcomputer programming control, and further carries out high-efficiency and reliable high-temperature protection on the silicon controlled rectifier, and improves the safety and stability of loads or products controlled by the silicon controlled rectifier.
As an alternative implementation manner, in the embodiment of the present invention, the resistance of the resistance variable unit 101 and the temperature of the thyristor unit 20 are in a negative correlation, when the temperature of the thyristor unit 20 is higher than the temperature threshold, the resistance of the resistance variable unit 101 is lower than the resistance threshold, and when the resistance of the resistance variable unit 101 is lower than the resistance threshold, the triode unit 102 is turned on, so that the trigger circuit path is turned on with the ground terminal.
Alternatively, the resistance variable unit 101 is a negative temperature coefficient thermistor NTC.
As an alternative implementation, in the embodiment of the present invention, as shown in fig. 2, the transistor unit 102 is an NPN transistor, the base b1 of the transistor unit 102 is connected to the second terminal of the resistance variable unit 101, the emitter e1 of the transistor unit 102 is connected to the ground terminal, and the collector c1 of the transistor unit 102 is connected to the trigger circuit path.
By setting the resistance variable unit 101 in this way, that is, when the temperature of the thyristor unit 20 increases, the resistance of the NTC decreases accordingly, then the voltage between the base b1 and the emitter e1 of the triode unit 102 (which is an NPN type triode) increases gradually, and when the resistance of the resistance variable unit 101 decreases to a certain resistance threshold, the voltage between the base b1 and the emitter e1 of the triode unit 102 reaches the turn-on voltage of the triode unit 102, and at this time, the collector c1 and the emitter e1 of the triode unit 102 are turned on, so that the trigger circuit path is turned on with the ground, thereby realizing the function of high temperature protection.
As an optional implementation manner, in this embodiment of the present invention, a first current limiting resistor 401 is further disposed between the second end of the resistance variable unit 101 and the base b1 of the triode unit 102, so as to limit the magnitude of the current of the branch circuit, so as to prevent the components connected in series from being burned out due to excessive current. Alternatively, the operator may also adjust the current-voltage relationship between the resistance variable unit 101 and the triode unit 102 by setting the size of the first current limiting resistor 401 to implement the above-mentioned setting of the resistance threshold and the temperature threshold in the high temperature protection. For example, the operator may determine the appropriate first current limiting resistor 401 according to the temperature-resistance variation relationship between the resistance variable unit 101 and the thyristor unit 20, the voltage relationship between the power supply and the ground, and the on voltage of the triode unit 102.
As an alternative implementation, in the embodiment of the present invention, the trigger circuit 30 of the triac unit 20 includes a triac unit 301, a base b2 of the triac unit 301 is connected to the control signal output Out of the control unit 10, an emitter e2 of the triac unit 301 is grounded, and a collector c2 of the triac unit 301 is connected to the trigger terminal of the triac unit 20.
In this alternative embodiment, the thyristor unit 20 is a bidirectional thyristor or a common thyristor, the triac unit 301 is an NPN type triode, and the triac unit 301 is configured to trigger a trigger terminal of the thyristor unit 20 to trigger the thyristor unit 20 when receiving a control signal.
As an optional implementation manner, in the embodiment of the present invention, a second current limiting resistor 402 is further disposed between the base b2 of the triac 301 and the control signal output terminal Out of the singlechip, so as to limit the magnitude of the current of the branch, so as to prevent the components connected in series from being burned Out due to excessive current.
As an alternative implementation manner, in the embodiment of the present invention, a current limiting resistor unit is further disposed between the collector c1 of the trigger transistor unit 301 and the trigger terminal of the thyristor unit 20. Optionally, in the embodiment of the present invention, the current limiting resistor unit includes a third current limiting resistor 403 and a fourth current limiting resistor 404 that are disposed in parallel, so as to limit the magnitude of the current of the branch circuit, so as to prevent the components connected in series from being burned out due to excessive current.
As an alternative implementation, in this embodiment of the present invention, a clamp resistor 405 is further disposed between the base b2 and the emitter e2 of the triac 301, so as to limit the voltage between the base b2 and the emitter e2 of the triac 301, so as to ensure the stability of the triode circuit.
As an alternative implementation, in the embodiment of the present invention, the resistance variable unit 101 is disposed near the thyristor unit 20, so that the resistance of the resistance variable unit 101 may vary with the temperature of the thyristor unit 20. Specifically, when the PCB board design is performed, the resistance variable unit 101 is disposed near the thyristor unit 20, an example is given in fig. 3, and referring to this example, a person skilled in the art can understand how to implement the technical details of disposing the resistance variable unit 101 near the thyristor unit 20 in this embodiment.
The apparatus embodiments described above are merely illustrative, wherein the modules illustrated as separate components may or may not be physically separate, and the components shown as modules may or may not be physical, i.e., may be located in one place, or may be distributed over a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
Finally, it should be noted that: the disclosure of the silicon controlled rectifier high temperature protection device and the circuit control system in the embodiment of the invention is only a preferred embodiment of the invention, and is only used for illustrating the technical scheme of the invention, but not limiting the technical scheme; although the invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that; the technical scheme recorded in the various embodiments can be modified or part of technical features in the technical scheme can be replaced equivalently; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (8)
1. A thyristor high temperature protection device disposed between a control unit and a thyristor unit, the device comprising:
the first end of the resistance variable unit is connected to a power supply, and the resistance of the resistance variable unit changes along with the temperature change of the silicon controlled rectifier unit;
the triode unit is respectively connected to the trigger circuit passage, the second end of the resistance variable unit and the ground end; the trigger circuit path is a connection circuit path between a control signal output end of the control unit and a control signal input end of a trigger circuit for driving the thyristor unit;
when the temperature of the controllable silicon unit is higher than a preset temperature threshold, the resistance of the resistance variable unit is changed, so that the triode unit is conducted, and the trigger circuit passage is conducted with the ground terminal;
wherein the resistance variable unit is a thermistor with a negative temperature coefficient, and/or the resistance variable unit is arranged close to the silicon controlled rectifier unit, so that the resistance of the resistance variable unit can change along with the temperature of the silicon controlled rectifier unit;
and the trigger circuit of the thyristor unit comprises a trigger triode unit, wherein the base electrode of the trigger triode unit is connected to the control signal output end of the control unit, the emitting electrode of the trigger triode unit is grounded, and the collecting electrode of the trigger triode unit is connected to the trigger end of the thyristor unit.
2. The high temperature protection device according to claim 1, wherein the resistance of the resistance variable unit is in a negative correlation with the temperature of the thyristor unit, when the temperature of the thyristor unit is higher than the temperature threshold, the resistance of the resistance variable unit is lower than the resistance threshold, and when the resistance of the resistance variable unit is lower than the resistance threshold, the triode unit is turned on, so that the trigger circuit path is turned on with the ground terminal.
3. The thyristor high temperature protection device according to claim 2, wherein the triode unit is an NPN type triode, a base electrode of the triode unit is connected to the second end of the resistance value variable unit, an emitter electrode of the triode unit is connected to the ground terminal, and a collector electrode of the triode unit is connected to the trigger circuit path.
4. The silicon controlled rectifier high temperature protection device according to claim 3, wherein a first current limiting resistor is further arranged between the second end of the resistance variable unit and the base electrode of the triode unit.
5. The silicon controlled rectifier high temperature protection device according to claim 1, wherein a second current limiting resistor is further arranged between the base electrode of the triode unit and the control signal output end of the singlechip, and/or a current limiting resistor unit is further arranged between the collector electrode of the triode unit and the trigger end of the silicon controlled rectifier unit.
6. The thyristor high temperature protection device according to claim 5, wherein the current limiting resistor unit comprises a third current limiting resistor and a fourth current limiting resistor arranged in parallel.
7. The thyristor high temperature protection device according to claim 1, wherein a clamping resistor is further provided between the base and the emitter of the triac.
8. A thyristor circuit control system, characterized in that the system comprises a control unit, a thyristor unit and a thyristor high temperature protection device according to any one of claims 1-7.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109101053A (en) * | 2018-10-13 | 2018-12-28 | 贾巧凤 | Temperature control equipment |
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| TW201136081A (en) * | 2010-04-01 | 2011-10-16 | Hon Hai Prec Ind Co Ltd | Electronic device having high temperature protection circuit |
| CN206041466U (en) * | 2016-09-12 | 2017-03-22 | 广州视源电子科技股份有限公司 | Take switching power supply circuit of excess temperature protection |
| CN106681397B (en) * | 2017-02-22 | 2018-10-30 | 广东美的白色家电技术创新中心有限公司 | Electrical equipment and PTC electric heater control circuit for it |
| CN107123967A (en) * | 2017-05-22 | 2017-09-01 | 合肥联信电源有限公司 | A kind of IGCT thermal protection circuit |
| CN208209511U (en) * | 2018-06-15 | 2018-12-07 | 沈阳市鑫源节能设备有限公司 | The protection circuit of silicon-controlled breakdown |
| CN208461794U (en) * | 2018-06-29 | 2019-02-01 | 佛山市谱德电子科技有限公司 | A kind of silicon controlled control circuit |
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| CN109101053A (en) * | 2018-10-13 | 2018-12-28 | 贾巧凤 | Temperature control equipment |
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