CN112234582A - Overvoltage detection circuit and control device thereof - Google Patents

Overvoltage detection circuit and control device thereof Download PDF

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Publication number
CN112234582A
CN112234582A CN202011002911.XA CN202011002911A CN112234582A CN 112234582 A CN112234582 A CN 112234582A CN 202011002911 A CN202011002911 A CN 202011002911A CN 112234582 A CN112234582 A CN 112234582A
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China
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voltage
circuit
resistor
analog quantity
capacitor
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CN202011002911.XA
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CN112234582B (en
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苏长记
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Etekcity Corp
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Etekcity Corp
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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
    • H02H7/10—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 converters; for rectifiers
    • H02H7/12—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 converters; for rectifiers for static converters or rectifiers
    • H02H7/1213—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 converters; for rectifiers for static converters or rectifiers for DC-DC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements

Abstract

The invention provides an overvoltage detection circuit and a control device thereof.A first energy storage circuit converts a first voltage which is positively correlated with the voltage value of a power supply of equipment into a first voltage analog quantity which is negatively correlated with the first voltage and has a negative proportion relation with the first voltage, an output circuit outputs a second voltage analog quantity which is negatively correlated with the first voltage according to the first voltage analog quantity and a constant voltage analog quantity, so that the second voltage analog quantity is negatively correlated with the voltage value of the power supply of the equipment, namely the larger the voltage value of the power supply is, the smaller the second voltage analog quantity is, when the second voltage analog quantity is smaller than a reference voltage, the voltage value of the power supply at the moment is known to be larger than the working voltage of the equipment, and a comparison circuit outputs a control signal for closing the equipment so as to protect the equipment from overvoltage.

Description

Overvoltage detection circuit and control device thereof
Technical Field
The application belongs to the technical field of overvoltage protection, and particularly relates to an overvoltage detection circuit and a control device thereof.
Background
When equipment of low-voltage inserts high voltage, the power rises by a wide margin, and equipment is overheated to lead to the fire accident easily, and when equipment was in wrong access high voltage power supply or the power supply of access suddenly when unusual rising, it leads to unexpected emergence just to appear equipment overheated easily, therefore traditional equipment exists and leads to unexpected problem when power supply voltage is higher than normal voltage.
Disclosure of Invention
The application aims to provide an overvoltage detection circuit, and aims to solve the problem that when a high voltage is accessed, the conventional equipment is easy to cause accidents.
A first aspect of an embodiment of the present application provides an overvoltage detection circuit, including:
the first energy storage circuit is configured to convert the first voltage into a first voltage analog quantity; the absolute value of the first voltage analog quantity is positively correlated with the absolute value of the first voltage, and the polarity of the first voltage analog quantity is opposite to that of the first voltage;
the output circuit is connected with the first energy storage circuit and is configured to output the second voltage analog quantity according to the first voltage analog quantity and the constant voltage analog quantity, wherein the second voltage analog quantity is in negative correlation with the first voltage;
the comparison circuit is connected with the energy storage circuit and is configured to compare the second voltage analog quantity with a reference voltage and output a control signal according to a comparison result so as to control equipment to start or stop;
wherein the first voltage is positively correlated with a voltage value of a power supply source of the apparatus.
In one embodiment, the first energy storage circuit comprises a first diode and a first capacitor; the positive electrode of the first diode and the first end of the first capacitor are connected in common to form a first voltage analog quantity output end of the first energy storage circuit, the second end of the first capacitor is a first voltage input end of the first energy storage circuit, the second end of the first capacitor is connected with a first power ground, and the negative electrode of the first diode is connected with a second power ground.
In one embodiment, the first energy storage circuit further comprises a first resistor; the anode of the first diode is connected with the first end of the first resistor, and the second end of the first resistor and the first end of the first capacitor are connected in common to form a first voltage analog quantity output end of the first energy storage circuit.
In one embodiment, the output circuit comprises a second resistor, a third resistor and a fourth resistor; the first end of the second resistor is the first voltage analog input end of the output circuit, the first end of the fourth resistor is the constant voltage analog input end of the output circuit, the first end of the third resistor is connected with the first power ground, and the second end of the second resistor, the second end of the third resistor and the second end of the fourth resistor are connected together to form the second voltage analog output end of the output circuit.
In one embodiment, the over-voltage detection circuit further includes: vary voltage circuit, feedback circuit, second energy storage circuit and control circuit:
the transformation circuit and the feedback circuit are both connected with the control circuit, and the control circuit is configured to output a conversion control signal to the transformation circuit according to the feedback voltage output by the feedback circuit;
the voltage transformation circuit is configured to input a first direct current voltage according to the conversion control signal and convert the first direct current voltage into the first voltage, and convert the first direct current voltage into a second voltage when the input of the first direct current voltage is stopped; wherein the first voltage is positively correlated with the first direct current voltage;
the feedback circuit is connected with the transformation circuit and is configured to output the feedback voltage according to the second voltage; and
the second energy storage circuit is respectively connected with the voltage transformation circuit and the output circuit and is configured to convert the second voltage into a third voltage analog quantity; the third voltage analog quantity is the constant voltage analog quantity.
In one embodiment, the feedback circuit comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, an optocoupler, a controllable precision voltage regulator, a third capacitor and a fourth capacitor;
the first end of the fifth resistor, the first end of the sixth resistor and the anode of the optocoupler are connected in common, the cathode of the controllable precise voltage-stabilizing source, the cathode of the optocoupler, the second end of the sixth resistor and the first end of the seventh resistor are connected in common, the second end of the seventh resistor and the first end of the third capacitor are connected in common, the control electrode of the controllable precise voltage-stabilizing source, the second end of the third capacitor, the first end of the eighth resistor and the first end of the ninth resistor are connected in common, the second end of the ninth resistor, the emitter of the optocoupler and the anode of the controllable precise voltage-stabilizing source are all connected with a first power ground, the second end of the fifth resistor and the second end of the eighth resistor are connected in common to form a second voltage input end of the feedback circuit, and the collector of the optocoupler and the first end of the fourth capacitor are connected in common to form a feedback voltage output end of the feedback circuit, and the second end of the fourth capacitor is connected with the first power ground.
In one embodiment, the second energy storage circuit comprises a second capacitor and a second diode; the anode of the second diode is a second voltage input end of the second energy storage circuit, the cathode of the second diode and the first end of the second capacitor are connected in common to form a third voltage analog output end of the second energy storage circuit, and the second end of the second capacitor is connected with the first power ground.
In one embodiment, the transformation circuit includes a first transformer, the first transformer includes a first primary winding, a first secondary winding, and an auxiliary winding, and the first primary winding is coupled to the first secondary winding and the auxiliary winding respectively; the first primary winding is a first direct-current voltage input end of the transformation circuit, the first end of the first secondary winding is a second voltage output end of the transformation circuit, the first end of the auxiliary winding of the first transformer is a first voltage output end of the transformation circuit, the second end of the first secondary winding is a second power ground, and the second end of the auxiliary winding of the first transformer is connected with the first power ground.
In one embodiment, the transformation circuit includes a second transformer, the second transformer includes a second primary winding and a second secondary winding, and the second primary winding and the second secondary winding are coupled and connected; the second primary winding is a first direct-current voltage input end of the transformation circuit, the first end of the second secondary winding is a second voltage output end of the transformation circuit and the second power ground, and the second end of the second secondary winding is a first voltage output end of the transformation circuit.
A first aspect of embodiments of the present application provides a control device, comprising a switching circuit and an overvoltage detection circuit as in any of the embodiments of the first aspect; the comparison circuit is connected with the switch circuit;
the switching circuit is configured to control the device to start or stop when the control signal is input.
Compared with the prior art, the embodiment of the application has the advantages that:
1. the first energy storage circuit converts a first voltage which is in positive correlation with a voltage value of a power supply of equipment into a first voltage analog quantity which is in negative correlation with the first voltage and in negative proportion, the output circuit outputs a second voltage analog quantity which is in negative correlation with the first voltage according to the first voltage analog quantity and the constant voltage analog quantity, therefore, the second voltage analog quantity is in negative correlation with the voltage value of the power supply of the equipment, namely the larger the voltage value of the power supply is, the smaller the second voltage analog quantity is, when the second voltage analog quantity is smaller than a reference voltage, the voltage value of the power supply at the moment is known to be larger than the working voltage of the equipment, and the comparison circuit outputs a control signal for closing the equipment so as to achieve overvoltage protection of the equipment.
2. The second voltage analog quantity and the first voltage become negative correlation, when the first voltage which is input is abnormally increased due to lightning stroke or overhigh input voltage, the second voltage analog quantity and the first voltage become negative correlation, so that the second voltage analog quantity cannot be increased along with the first voltage, and a comparison circuit of a later stage can be protected from being influenced by the high voltage.
Drawings
FIG. 1 is a first exemplary functional block diagram of an over-voltage detection circuit provided by an embodiment of the present application;
FIG. 2 is a first exemplary circuit schematic of an over-voltage detection circuit provided by an embodiment of the present application;
FIG. 3 is a second exemplary circuit schematic of an over-voltage detection circuit provided by an embodiment of the present application;
FIG. 4 is a second exemplary functional block diagram of an over-voltage detection circuit provided by an embodiment of the present application;
FIG. 5 is a third exemplary functional block diagram of an over-voltage detection circuit provided by an embodiment of the present application;
FIG. 6 is a fourth exemplary functional block diagram of an over-voltage detection circuit provided by an embodiment of the present application;
fig. 7 is a first exemplary functional block diagram of a control device according to an embodiment of the present disclosure;
fig. 8 is a second exemplary functional block diagram of a control device according to an embodiment of the present application;
fig. 9 is a first exemplary circuit schematic diagram of a control device according to an embodiment of the present application.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Fig. 1 shows a schematic block diagram of an over-voltage detection circuit provided in an embodiment of the present application, and for convenience of illustration, only the portions related to the embodiment are shown, and detailed as follows:
an overvoltage detection circuit includes a first energy storage circuit 142, an output circuit 143, and a comparison circuit 150.
A first energy storage circuit 142 configured to convert the first voltage into a first voltage analog quantity; the absolute value of the first voltage analog quantity is positively correlated with the absolute value of the first voltage, and the first voltage analog quantity is opposite in polarity to the first voltage.
And an output circuit 143, connected to the first energy storage circuit 142, configured to output a second voltage analog quantity according to the first voltage analog quantity and the constant voltage analog quantity, wherein the second voltage analog quantity is in negative correlation with the first voltage.
And the comparison circuit 150 is connected with the energy storage circuit and is configured to compare the second voltage analog quantity with the reference voltage and output a control signal according to the comparison result so as to control the equipment to start or stop.
Wherein the first voltage is positively correlated with a voltage value of a power supply source of the device.
In the present embodiment, the first voltage is positively correlated with the voltage value of the power supply source of the equipment, the first energy storage circuit 142 converts the first voltage into a first voltage analog quantity which is negatively correlated and negatively proportional to the first voltage, the absolute value of the first voltage analog quantity increases as the absolute value of the first voltage increases, but the first voltage analog quantity is opposite in polarity to the first voltage, so the first voltage analog quantity is negatively correlated with the first voltage, the actual value of the first voltage becomes smaller as the first voltage increases, and the first voltage analog quantity is always negative because the first voltage is always positive, for example, the first voltage analog quantity is-10V when the first voltage is 220V, the first voltage analog quantity is-5V when the first voltage is 110V, the output circuit 143 outputs a second voltage analog quantity negatively correlated with the first voltage according to the first voltage analog quantity and the constant voltage analog quantity, therefore, the second voltage analog quantity is in negative correlation with the voltage value of the power supply of the equipment, and the comparison circuit 150 outputs a control signal to stop the control equipment when the second voltage analog quantity is smaller than the reference voltage, so that the second voltage analog quantity is smaller when the voltage value of the power supply is larger, and the comparison circuit 150 controls the equipment to stop working when the voltage of the power supply exceeds a preset protection value, so as to protect the equipment from overvoltage.
Because the second voltage analog quantity is in negative correlation with the first voltage, when the first voltage is abnormally increased due to lightning strike or overhigh input voltage, the second voltage analog quantity cannot be increased along with the first voltage due to the negative correlation between the second voltage analog quantity and the first voltage, and the comparison circuit 150 at the later stage can be protected from the influence of high voltage; the polarity of the constant voltage analog quantity is opposite to that of the first voltage analog quantity, and the constant voltage analog quantity has the function of enabling the second voltage analog quantity to be larger than the value of the reference voltage when the first voltage does not exceed the preset protection value, so that the comparison circuit 150 stops outputting the control signal to enable the equipment to start working.
In another embodiment, the comparison circuit 150 outputs a control signal to enable the control device to start operating when the second voltage analog quantity is greater than the reference voltage, and the comparison circuit 150 stops outputting the control signal to enable the control device to stop operating when the second voltage analog quantity is less than the reference voltage.
Referring to fig. 2, in one embodiment, the first energy storage circuit 142 includes a first diode D2 and a first capacitor C2; the positive electrode of the first diode D2 and the first end of the first capacitor C2 are connected in common to form a first voltage analog output end of the first energy storage circuit 142, the second end of the first capacitor C2 is a first voltage input end of the first energy storage circuit 142, the second end of the first capacitor C2 is connected to the first power ground, and the negative electrode of the first diode D2 is connected to the second power ground.
The first power ground and the second power ground are both referred to as a first power cathode and a second power cathode, wherein the first power ground and the second power ground are not communicated and are independent.
In this embodiment, since the second terminal of the first capacitor C2 is the first voltage input terminal, and the first terminal of the first capacitor C2 is connected to the positive electrode of the first diode D2, and since the first power ground is not connected to the second power ground, the first voltage does not directly flow through the second power ground to form a loop via the first power ground, so that the current for charging the first capacitor C2 at the first voltage flows to the second terminal of the first capacitor C2 to the first terminal of the first capacitor C2, so that the second terminal of the first capacitor C2 is positive, and since the second terminal of the first capacitor C2 is connected to the first power ground, the second terminal of the first capacitor C2 is 0 potential with respect to the first power ground, so that the first terminal of the first capacitor C2 is negative potential with respect to the first power ground, so that the analog quantity of the first voltage output by the first terminal of the first capacitor C2 is negative polarity, in combination with the first voltage analog quantity being correlated with the first voltage, the absolute value of the first voltage analog quantity is positively correlated with the absolute value of the first voltage, and the polarities of the first voltage analog quantity and the first voltage are opposite, so that the actual value of the first voltage analog quantity is negatively correlated with the actual value of the first voltage.
Referring to fig. 2 and fig. 3, in an embodiment, the output circuit 143 includes a second resistor R2, a third resistor R3, and a fourth resistor R4; a first end of the second resistor R2 is a first voltage analog input end of the output circuit 143, a first end of the fourth resistor R4 is a third voltage analog input end of the output circuit 143, a first end of the third resistor R3 is connected to the first power ground, and a second end of the second resistor R2, a second end of the third resistor R3 and a second end of the fourth resistor R4 are connected in common to form a second voltage analog output end of the output circuit 143.
Referring to fig. 2 and 3, in one embodiment, the comparison circuit 150 includes an operational amplifier U2; the non-inverting input terminal of the operational amplifier U2 is the second voltage analog input terminal of the comparison circuit 150, the inverting input terminal of the operational amplifier U2 is the reference voltage input terminal of the comparison circuit 150, and the output terminal of the operational amplifier U2 is the control signal output terminal of the comparison circuit 150.
Referring to fig. 3, in an embodiment, the first energy storage circuit 142 further includes a first resistor R1; the anode of the first diode D2 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 and the first end of the first capacitor C2 are connected in common to form the first voltage analog output terminal of the first energy storage circuit 142. In the present embodiment, the first resistor R1 functions as a current limiting and voltage dividing function.
The overvoltage detection circuit shown in fig. 3 is described with reference to the operation principle, the first voltage charges the first capacitor C2, because the second terminal of the first capacitor C2 has a positive polarity and is connected to the first power ground, the first voltage analog output from the first terminal of the first capacitor C2 has a negative polarity, and the first voltage analog becomes smaller as the first voltage becomes larger, the first voltage analog is divided by the second resistor R2 and the third resistor R3 into the first capacitor C2, and then combined with the constant voltage analog input through the fourth resistor R4 to form the second voltage analog, and output to the non-inverting input terminal of the operational amplifier, the reference voltage is input to the inverting input terminal of the operational amplifier, and the operational amplifier outputs a control signal (low level signal) when the second voltage analog is smaller than the reference voltage.
Referring to fig. 4, in an embodiment, the overvoltage detection circuit further includes a transformation circuit 110, a feedback circuit 120, a control circuit 130, and a second energy storage circuit 141.
The transformer circuit 110 and the feedback circuit 120 are both connected to the control circuit 130, and the control circuit 130 is configured to output a conversion control signal to the transformer circuit according to a feedback voltage output by the feedback circuit.
The transformer circuit 110 is configured to input a first direct current voltage according to the conversion control signal and convert the first direct current voltage into a first voltage, and convert the first direct current voltage into a second voltage when the input of the first direct current voltage is stopped, wherein the first voltage is positively correlated with the first direct current voltage.
The feedback circuit 120 is connected to the transforming circuit 110 and configured to output a feedback voltage according to the second voltage.
And the second energy storage circuit 141 is respectively connected with the transformation circuit 110 and the output circuit 143, and is configured to convert the second voltage into a third voltage analog quantity, wherein the third voltage analog quantity is a constant voltage analog quantity.
In the present embodiment, the feedback circuit 120 converts the second voltage into the feedback voltage and outputs the feedback voltage to the control circuit 130, the control circuit 130 generates the conversion control signal according to the feedback voltage to control the transformer circuit 110 to convert the first direct current voltage into the first voltage and the second voltage, and the analog values of the second voltage and the third voltage are maintained at constant values through the feedback regulation.
In some embodiments, the constant voltage analog may be provided by an external power source.
Referring to fig. 5, in an embodiment, the feedback circuit 120 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, an optocoupler U3, a controllable precision regulator U4, a third capacitor C3, and a fourth capacitor C4;
the first end of the fifth resistor R5, the first end of the sixth resistor R6 and the anode of the optocoupler U3 are connected in common, the negative electrode of the controllable precise voltage-stabilizing source U4, the negative electrode of the optocoupler U3, the second end of the sixth resistor R6 and the first end of the seventh resistor R7 are connected together, the second end of the seventh resistor R7 is connected with the first end of the third capacitor C3, a control electrode of the controllable precise voltage-stabilizing source U4, a second end of the third capacitor C3, a first end of the eighth resistor R8 and a first end of the ninth resistor R9 are connected in common, a second end of the ninth resistor R9, an emitter of the optocoupler U3 and a positive electrode of the controllable precise voltage-stabilizing source U4 are all connected with a first power ground, a second end of the fifth resistor R5 and a second end of the eighth resistor R8 are connected in common to form a second voltage input end of the feedback circuit 120, a collector of the optocoupler U3 and a first end of the fourth capacitor C4 are connected in common to form a feedback voltage output end of the feedback circuit 120, and a second end of the fourth capacitor C4 is connected with the first power ground.
Referring to fig. 5, in an embodiment, the transforming circuit 110 includes a first transformer T1, the first transformer T1 includes a first primary winding, a first secondary winding, and an auxiliary winding, and the first primary winding is coupled to the first secondary winding and the auxiliary winding respectively; the first primary winding is a first direct-current voltage input end of the transformation circuit 110, the first end of the first secondary winding is a second voltage output end of the transformation circuit 110, the first end of the auxiliary winding of the first transformer T1 is a first voltage output end of the transformation circuit 110, the second end of the first secondary winding is a second power ground, and the second end of the auxiliary winding of the first transformer T1 is connected with the first power ground.
Specifically, the first end of the first primary winding is a first direct-current voltage input end, the second end of the first primary winding is connected with a second power ground, the second end of the first primary winding and the second end of the auxiliary winding are homonymous ends, and the second end of the first primary winding and the first end of the first secondary winding are homonymous ends.
Referring to fig. 5, in an embodiment, the control circuit 130 includes a voltage modulation chip U1, a field effect transistor Q1, and a twelfth resistor R12, a ground terminal GND of the voltage modulation chip U1 is connected to a first power ground, a supply voltage terminal VCC of the voltage modulation chip U1 is connected to an internal power supply, a current sampling terminal CS of the voltage modulation chip U1, a source of the field effect transistor Q1, and a first terminal of the twelfth resistor R12 are commonly connected, a voltage feedback terminal FB of the voltage modulation chip U1 is a feedback voltage input terminal of the control circuit 130, a field effect transistor control signal terminal GATE of the voltage modulation chip U1 is connected to a GATE of the field effect transistor Q1, a second terminal of the twelfth resistor R12 is connected to the first power ground, and a drain of the field effect transistor Q1 is a conversion control signal output terminal of the control circuit 130.
Referring to fig. 5, in an embodiment, the reference voltage may be output by a voltage divider circuit formed by a tenth resistor R10 and an eleventh resistor R11.
The overvoltage detection circuit shown in fig. 5 is described with reference to the operation principle, when the voltage modulation chip U1 outputs a high level to the fet Q1, the fet Q1 is turned on, the second end of the first primary winding is grounded through the fet Q1 and the twelfth resistor R12, a first dc voltage flows through the first primary winding, the auxiliary winding of the first transformer T1 electromagnetically senses a first voltage, the first voltage charges the first capacitor C2 through the first diode D2, because the second end of the first capacitor C2 is the first voltage input end, and the first end of the first capacitor C2 is connected to the positive electrode of the first diode D2, the current for charging the first capacitor C2 at the first voltage flows to the first end of the first capacitor C2 from the second end of the first capacitor C2, so the second end of the first capacitor C2 has a positive polarity, and because the second end of the first capacitor C2 is connected to the first power ground, therefore, the second end of the first capacitor C2 is at 0 potential with respect to the first power ground, so the first end of the first capacitor C2 is at negative potential with respect to the first power ground, so the first voltage analog quantity output by the first end of the first capacitor C2 is negative polarity, the first voltage analog quantity is related to the first voltage, so the first voltage analog quantity is negatively related to the first voltage and has a negative proportional relation, when the voltage modulation chip U1 outputs low level to the fet Q1, the fet Q1 is turned off, the first primary winding is equivalent to open circuit, since the first dc voltage in the first primary winding cannot be transient, so the secondary winding of the first transformer T1 electromagnetically induces a second voltage, which is in reverse phase with the first voltage, the second voltage charges the second capacitor C1 through the second diode D1, and the second voltage acts on the U3 through the sixth resistor R6, the optocoupler U3 feedbacks the second voltage generating feedback voltage to the voltage feedback terminal FB of the voltage modulation chip U1, the voltage modulation chip U1 adjusts the time proportion of outputting low level and high level according to the feedback voltage, so that the second voltage keeps a constant value, the first capacitor C2 outputs a third voltage analog quantity with a constant value, for example, when the constant value of the second voltage is 5V, when the current voltage value of the second voltage is increased to be more than 5V, the illumination intensity of the light emitting diode of the optocoupler U3 is increased, the conducting current of the phototriode of the optocoupler U3 is increased, the voltage of the voltage feedback terminal FB of the voltage modulation chip U1 is decreased, the voltage of the voltage feedback terminal FB of the voltage modulation chip U1 is compared with the triangular wave connected at the reverse input end inside the voltage modulation chip U1, the duty ratio of outputting high level is decreased, the conducting time of the field effect transistor Q1 is decreased, so that the second voltage is decreased, the voltage modulation chip U1 controls the on-off ratio Qt of the fet Q1 to be (Vt × N1/N2)/((Vt × N1/N2) + Vdc), where Vt is a constant value of the second voltage, N1 is the number of turns of the first primary winding, N2 is the number of turns of the first secondary winding, and Vdc is a current voltage value of the second voltage, when Vt is 5V, the voltage modulation chip U1 controls the on-off ratio Qt of the fet Q1 to be (5V × N1/N2) ((5V × N1/N2) + Vdc) when Vt is 5V, the voltage of the non-inverting input terminal of the operational amplifier U84 depends on the voltage of the second capacitor C1 and the divided voltage, the divided voltage is the voltage of the second capacitor R2 and the third resistor R3 divided by the voltage of the first capacitor C2, the operational amplifier U5 satisfies the second analog input terminal of the second capacitor M1, and the second input terminal of the analog input terminal of the second capacitor M1 is assumed constant value, the voltage of the first capacitor C2 is UC2, and since the second end of the first capacitor C2 is at 0 potential, the second voltage analog quantity output by the first end of the first capacitor C2 is-UC 2, so that the non-inverting input end of the operational amplifier U2 satisfies (-UC2-X)/R2+ (M-X)/R4 ═ X/R3, it can be known that X is negatively correlated with UC2, so that the second voltage analog quantity input by the non-inverting input end of the operational amplifier U2 is negatively correlated with the first direct current voltage, and therefore, on the premise that the reference voltage output by the tenth resistor R10 and the eleventh resistor R11 is unchanged, the first direct current voltage is larger, the second voltage analog quantity is smaller, and when the second voltage analog quantity is smaller than the reference voltage, the operational amplifier U2 outputs a low-level control device to stop operating. In the following description, the voltage X at the non-inverting input terminal of the operational amplifier U2 is calculated, assuming that the number of turns N1 of the first primary winding is 100, the number of turns N2 of the first secondary winding is 10, the number of turns N3 of the auxiliary winding is 5, the resistance of the first resistor R1 is 1K, the resistance of the second resistor R2 is 8K, the resistance of the third resistor R3 is 2K, the resistance of the fourth resistor R4 is 2K, the constant voltage analog is 5V, the reference voltage is 1V, when the voltage input to the first primary winding is 140V, the voltage of the second capacitor C1 is 140V/100 5V/7V, the first voltage analog is-7V, the voltage X at the non-inverting input terminal of the operational amplifier U2 satisfies kirschner's law, and thus satisfies (-7V-X)/8K + (5-X)/2K, and thus X > 1.44V, at this time, the voltage X of the non-inverting input terminal of the operational amplifier U2 is greater than the reference voltage, so the operational amplifier U2 outputs a high level to control the device to work normally; when the voltage input into the first primary winding is 200V, the voltage of the second capacitor C1 is 200V/100 × 5 to 10V, the first voltage analog quantity is-10V, and the voltage X at the non-inverting input terminal of the operational amplifier U2 satisfies kirchhoff's law, and therefore satisfies (-10V-X)/8K + (5-X)/2K to X/2K, and therefore X is 1.11V > 1V, and at this time, the voltage X at the non-inverting input terminal of the operational amplifier U2 is greater than the reference voltage, so that the operational amplifier U2 outputs a high-level control device to operate normally; when the voltage input to the first primary winding is 220V, the voltage of the second capacitor C1 is 220V/100 × 5 to 11V, the first voltage analog quantity is-11V, and the voltage X at the non-inverting input terminal of the operational amplifier U2 satisfies kirchhoff's law, and therefore satisfies (-11V-X)/8K + (5-X)/2K to X/2K, and therefore X is 1V to 1V, and the voltage X at the non-inverting input terminal of the operational amplifier U2 is equal to the reference voltage, so that the output of the operational amplifier U2 remains unchanged, and generally, since the amplification factor of the operational amplifier U2 is large, the non-inverting input terminal of the operational amplifier U2 is rarely equal to the reference voltage; when the voltage input to the first primary winding is greater than 220V, X is less than 1V, and the voltage X at the non-inverting input terminal of the operational amplifier U2 is less than the reference voltage, so the operational amplifier U2 outputs a low level control device to stop working to protect the device.
Referring to fig. 6, in one embodiment, the present embodiment is different from the above embodiments only in that: the transformation circuit 110 includes a second transformer T2, the second transformer T2 includes a second primary winding and a second secondary winding, and the second primary winding and the second secondary winding are coupled; the second primary winding is a first direct-current voltage input end of the transformer circuit 110, a first end of the second secondary winding is a second voltage output end of the transformer circuit 110 and a second power ground, and a second end of the second secondary winding is a first voltage output end of the transformer circuit 110.
When the second end of the second secondary winding outputs the first voltage, the first end of the second secondary winding is used as a second power ground, the first end of the second primary winding is a first direct-current voltage input end, the second end of the second primary winding is connected with the second power ground, and the second end of the second primary winding and the second end of the second secondary winding are homonymous ends.
The working principle of this embodiment differs from the above embodiments only in that: when the voltage modulation chip U1 outputs a high level to the field-effect transistor Q1, the field-effect transistor Q1 is turned on, the second end of the second primary winding is grounded through the field-effect transistor Q1 and the twelfth resistor R12, the first direct-current voltage flows through the second primary winding, the first direct-current voltage gradually increases at the second primary winding, the second secondary winding electromagnetically induces a first voltage, the first voltage charges the first capacitor C2 through the fourth diode D4, and the first voltage cannot charge the second capacitor C1 due to the reverse blocking effect of the third diode D3; when the voltage modulation chip U1 outputs a low level to the fet Q1, the fet Q1 is turned off, the second primary winding is equivalent to an open circuit, but the first dc voltage in the second primary winding cannot be transient, and the first dc voltage in the second primary winding gradually decreases, so that the secondary winding of the second transformer T2 electromagnetically induces a second voltage that is opposite in phase to the first voltage, and the second voltage can charge the second capacitor C1 through the third diode D3.
Referring to fig. 7, an embodiment of the present application further provides a control apparatus, which includes a switch circuit 400 and the overvoltage detection circuit according to any of the above embodiments, the comparison circuit 150 is connected to the switch circuit 400, the switch circuit 400 is configured to control a device to start or stop when a control signal is input, and the control apparatus of the present embodiment includes the overvoltage detection circuit according to any of the above embodiments, so that the control apparatus of the present embodiment at least has the corresponding advantages of any of the above embodiments.
Referring to fig. 8 and 9, in an embodiment, the control apparatus further includes a rectifying circuit 200 and a filtering circuit 300, the rectifying circuit 200 is connected to the filtering circuit 300, the control circuits 130 are respectively connected to the filtering circuit 300, the comparing circuit 150 is connected to the switching circuit 400, the rectifying circuit 200 is configured to rectify an input ac current into a third dc voltage, the filtering circuit 300 is configured to convert the third dc voltage into a first dc voltage, and the switching circuit 400 is configured to control the device to start or stop when a control signal is input, where the ac current is a power supply of the device. Since the control device of this embodiment includes the overvoltage detection circuit of any one of the above embodiments, the control device of this embodiment has at least the corresponding advantages of any one of the above embodiments.
The overvoltage detection circuit and the control device of the application are applied to equipment in practice, including but not limited to air fryer, humidifier, heater and the like, and are used for cutting off power supply to the equipment when the power supply of the equipment is in overvoltage, so that the equipment is protected.
The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims (10)

1. An overvoltage detection circuit, comprising:
the first energy storage circuit is configured to convert the first voltage into a first voltage analog quantity; the absolute value of the first voltage analog quantity is positively correlated with the absolute value of the first voltage, and the polarity of the first voltage analog quantity is opposite to that of the first voltage;
the output circuit is connected with the first energy storage circuit and is configured to output the second voltage analog quantity according to the first voltage analog quantity and the constant voltage analog quantity, wherein the second voltage analog quantity is in negative correlation with the first voltage;
the comparison circuit is connected with the energy storage circuit and is configured to compare the second voltage analog quantity with a reference voltage and output a control signal according to a comparison result so as to control equipment to start or stop;
wherein the first voltage is positively correlated with a voltage value of a power supply source of the apparatus.
2. The overvoltage detection circuit of claim 1, wherein the first energy storage circuit includes a first diode and a first capacitor; the positive electrode of the first diode and the first end of the first capacitor are connected in common to form a first voltage analog quantity output end of the first energy storage circuit, the second end of the first capacitor is a first voltage input end of the first energy storage circuit, the second end of the first capacitor is connected with a first power ground, and the negative electrode of the first diode is connected with a second power ground.
3. The overvoltage detection circuit of claim 2, wherein the first energy storage circuit further comprises a first resistor; the anode of the first diode is connected with the first end of the first resistor, and the second end of the first resistor and the first end of the first capacitor are connected in common to form a first voltage analog quantity output end of the first energy storage circuit.
4. The overvoltage detection circuit of claim 1, wherein the output circuit includes a second resistor, a third resistor, and a fourth resistor; the first end of the second resistor is the first voltage analog input end of the output circuit, the first end of the fourth resistor is the constant voltage analog input end of the output circuit, the first end of the third resistor is connected with the first power ground, and the second end of the second resistor, the second end of the third resistor and the second end of the fourth resistor are connected together to form the second voltage analog output end of the output circuit.
5. The overvoltage detection circuit of claim 1, further comprising a voltage transformation circuit, a feedback circuit, a second energy storage circuit, and a control circuit:
the transformation circuit and the feedback circuit are both connected with the control circuit, and the control circuit is configured to output a conversion control signal to the transformation circuit according to the feedback voltage output by the feedback circuit;
the voltage transformation circuit is configured to input a first direct current voltage according to the conversion control signal and convert the first direct current voltage into the first voltage, and convert the first direct current voltage into a second voltage when the input of the first direct current voltage is stopped; wherein the first voltage is positively correlated with the first direct current voltage;
the feedback circuit is connected with the transformation circuit and is configured to output the feedback voltage according to the second voltage; and
the second energy storage circuit is respectively connected with the voltage transformation circuit and the output circuit and is configured to convert the second voltage into a third voltage analog quantity; the third voltage analog quantity is the constant voltage analog quantity.
6. The overvoltage detection circuit according to claim 5, wherein the feedback circuit comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, an optocoupler, a controllable precision voltage regulator, a third capacitor and a fourth capacitor;
the first end of the fifth resistor, the first end of the sixth resistor and the anode of the optocoupler are connected in common, the cathode of the controllable precise voltage-stabilizing source, the cathode of the optocoupler, the second end of the sixth resistor and the first end of the seventh resistor are connected in common, the second end of the seventh resistor and the first end of the third capacitor are connected in common, the control electrode of the controllable precise voltage-stabilizing source, the second end of the third capacitor, the first end of the eighth resistor and the first end of the ninth resistor are connected in common, the second end of the ninth resistor, the emitter of the optocoupler and the anode of the controllable precise voltage-stabilizing source are all connected with a first power ground, the second end of the fifth resistor and the second end of the eighth resistor are connected in common to form a second voltage input end of the feedback circuit, and the collector of the optocoupler and the first end of the fourth capacitor are connected in common to form a feedback voltage output end of the feedback circuit, and the second end of the fourth capacitor is connected with the first power ground.
7. The overvoltage detection circuit of claim 5, wherein the second energy storage circuit includes a second capacitor and a second diode; the anode of the second diode is a second voltage input end of the second energy storage circuit, the cathode of the second diode and the first end of the second capacitor are connected in common to form a third voltage analog output end of the second energy storage circuit, and the second end of the second capacitor is connected with the first power ground.
8. The overvoltage detection circuit according to claim 5, wherein the transformation circuit comprises a first transformer, the first transformer comprising a first primary winding, a first secondary winding, and an auxiliary winding, the first primary winding being coupled to the first secondary winding and the auxiliary winding, respectively; the first primary winding is a first direct-current voltage input end of the transformation circuit, the first end of the first secondary winding is a second voltage output end of the transformation circuit, the first end of the auxiliary winding of the first transformer is a first voltage output end of the transformation circuit, the second end of the first secondary winding is a second power ground, and the second end of the auxiliary winding of the first transformer is connected with the first power ground.
9. The overvoltage detection circuit of claim 5, wherein the transformation circuit comprises a second transformer, the second transformer comprising a second primary winding and a second secondary winding, the second primary winding and the second secondary winding coupled together; the second primary winding is a first direct-current voltage input end of the transformation circuit, the first end of the second secondary winding is a second voltage output end of the transformation circuit and the second power ground, and the second end of the second secondary winding is a first voltage output end of the transformation circuit.
10. A control device comprising a switching circuit and an overvoltage detection circuit according to any one of claims 1 to 9; the comparison circuit is connected with the switch circuit;
the switching circuit is configured to control the device to start or stop when the control signal is input.
CN202011002911.XA 2020-09-22 2020-09-22 Overvoltage detection circuit and control device thereof Active CN112234582B (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004032979A (en) * 2002-05-08 2004-01-29 Seiko Epson Corp Output overvoltage protection circuit and constant voltage switching power supply circuit provided with tha same
CN102891466A (en) * 2011-07-22 2013-01-23 富泰华工业（深圳）有限公司 Overvoltage/overcurrent protection circuit
CN104716630A (en) * 2013-12-12 2015-06-17 北汽福田汽车股份有限公司 Over-voltage and over-current protection circuit for traction motor controller
US20160268911A1 (en) * 2013-01-08 2016-09-15 Power Integrations, Inc. Overvoltage protection circuit
CN107681636A (en) * 2017-11-22 2018-02-09 合肥惠科金扬科技有限公司 A kind of overvoltage crowbar and Switching Power Supply
CN108134366A (en) * 2017-12-21 2018-06-08 上海艾为电子技术股份有限公司 A kind of overvoltage crowbar, over-voltage protection method and device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004032979A (en) * 2002-05-08 2004-01-29 Seiko Epson Corp Output overvoltage protection circuit and constant voltage switching power supply circuit provided with tha same
CN102891466A (en) * 2011-07-22 2013-01-23 富泰华工业（深圳）有限公司 Overvoltage/overcurrent protection circuit
US20160268911A1 (en) * 2013-01-08 2016-09-15 Power Integrations, Inc. Overvoltage protection circuit
CN104716630A (en) * 2013-12-12 2015-06-17 北汽福田汽车股份有限公司 Over-voltage and over-current protection circuit for traction motor controller
CN107681636A (en) * 2017-11-22 2018-02-09 合肥惠科金扬科技有限公司 A kind of overvoltage crowbar and Switching Power Supply
CN108134366A (en) * 2017-12-21 2018-06-08 上海艾为电子技术股份有限公司 A kind of overvoltage crowbar, over-voltage protection method and device

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