Overvoltage detection circuit and electronic equipment

Abstract

The utility model discloses an overvoltage detection circuit and electronic equipment. The overvoltage detection circuit comprises a piezoresistor, a voltage detection module, a control module and a prompt module, the piezoresistor is connected in series between two power supply ends of a power supply to be detected, and the voltage detection module is connected with the piezoresistor and is used for generating a detection signal according to the voltage on the piezoresistor; the control module is connected with the voltage detection module and the prompt module, and is used for determining whether the to-be-detected power supply is overvoltage according to the detection signal, and controlling the prompt module to give out a prompt when overvoltage occurs. According to the utility model, the working safety, stability and reliability can be improved, and a user can be stably reminded of an overvoltage risk.

Description

Technical Field

[0001] The utility model relates to the technical field of overvoltage detection, in particular to an overvoltage detection circuit and electronic equipment. Background Art

[0002] Figure 1 It is an overvoltage detection circuit provided by the prior art, such as Figure 1 As shown, the indication circuit 200 of the existing overvoltage detection circuit is directly connected between the phase line and the neutral line of the AC power supply, which is not only unsafe but also easily damaged. Moreover, under AC voltages of different amplitudes, the brightness of the signal indicator LED1 in the indication circuit 200 will have relatively obvious differences. During normal operation, the light or screen will flicker under the action of the half-cycle power frequency, affecting the user experience. Utility Model Content

[0003] The utility model provides an overvoltage detection circuit and electronic equipment to improve the safety, stability and reliability of work and stably remind users of overvoltage risks.

[0004] In the first aspect, the utility model provides an overvoltage detection circuit, including: a varistor, a voltage detection module, a control module and a prompt module; the varistor is connected in series between two power supply ends of a power supply to be detected, and the voltage detection module is connected to the varistor, and is used to generate a detection signal according to the voltage on the varistor; the control module is respectively connected to the voltage detection module and the prompt module, and when an overvoltage occurs in the power supply to be detected, the control module drives the prompt module to issue a prompt according to the detection signal.

[0005] Optionally, the voltage detection module includes a voltage divider unit, a first switch unit and a second switch unit connected in sequence; the voltage divider unit is used to divide the voltage on the varistor and output it to the first switch unit; the first switch unit is turned on or off according to the voltage division of the varistor; the second switch unit is turned on when the first switch unit is turned off, and is turned off when the first switch unit is turned on.

[0006] Optionally, the voltage divider unit includes an anti-reverse diode and a voltage divider sub-unit; the positive electrode of the anti-reverse diode is connected to the varistor, and the negative electrode of the anti-reverse diode is connected in series with the voltage divider sub-unit and grounded.

[0007] Optionally, the first switching unit includes a first transistor, and the second switching unit includes a second transistor; the control end of the first transistor is connected to the output end of the voltage divider unit, the first end of the first transistor is connected to the control end of the second transistor, the second end of the first transistor is grounded, and the first transistor is used to be turned off according to a first level voltage and turned on according to a second level voltage; the first level voltage is less than the second level voltage; the first end of the second transistor is connected to the control module and to the first power supply end, and the second end of the second transistor is grounded.

[0008] Optionally, the first switch unit further includes a first capacitor; a first end of the first capacitor is connected to the control end of the first transistor, and a second end of the first capacitor is grounded.

[0009] Optionally, the second switch unit further includes a first resistor and a second resistor connected in series between the second power supply terminal and ground, and a common end of the first resistor and the second resistor is connected to the control end of the second transistor.

[0010] Optionally, the overvoltage detection circuit further includes an isolation module, the voltage detection module is connected to the control module via the isolation module, and the detection signal is converted by the isolation module and then transmitted to the control module.

[0011] Optionally, the voltage detection module is used to output a first detection signal when the power supply to be detected is overvoltage, and to output a second detection signal when the power supply to be detected is not overvoltage; the isolation module is used to output a corresponding first isolation signal according to the first detection signal, and to output a corresponding second isolation signal according to the second detection signal; the control module is used to determine whether the power supply to be detected is overvoltage based on the level duration of the first isolation signal and the level duration of the second isolation signal.

[0012] Optionally, the isolation module includes an optocoupler isolator, a third resistor and a fourth resistor; the first end of the third resistor is connected to the second power supply terminal, and the second end of the third resistor is connected to the first end of the optocoupler isolator; the second end of the optocoupler isolator is connected to the output end of the voltage detection module, the third end of the optocoupler isolator is grounded, and the fourth end of the optocoupler isolator is connected to the control module; the first end of the fourth resistor is connected to the first power supply terminal, and the second end of the fourth resistor is connected to the control module.

[0013] Optionally, the overvoltage detection circuit also includes a fuse, which is connected in series with the varistor, and the fuse blows when the current signal of the power supply to be detected is overcurrent; the control module is also used to determine that the varistor is short-circuited when it is determined that the detection signal output by the voltage detection module is a first detection signal, and the level duration of the first detection signal is greater than or equal to a set duration, and control the prompt module to issue a fault prompt.

[0014] Optionally, the prompt module includes a display screen or an indicator light.

[0015] In a second aspect, the utility model provides an electronic device, comprising the overvoltage detection circuit provided by any embodiment.

[0016] The overvoltage detection circuit provided by the embodiment of the utility model includes a varistor, a voltage detection module, a control module and a prompt module. The output end of the control module can output a stable voltage signal. Therefore, compared with the prior art in which the signal indicator light is directly connected between the phase line and the neutral line of the AC power supply, by connecting the prompt module to the output end of the control module, the prompt module is not easily damaged by the power supply to be detected, and the prompt signal of the prompt module is stable. In other words, the overvoltage detection circuit provided by the embodiment of the utility model can stably and reliably remind the user of the risk of overvoltage, thereby improving the user experience.

[0017] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is an overvoltage detection circuit provided by the prior art;

[0020] Figure 2 It is a structural schematic diagram of an overvoltage detection circuit provided by an embodiment of the utility model;

[0021] Figure 3 It is a structural schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model;

[0022] Figure 4 It is a structural schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model;

[0023] Figure 5 It is a structural schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model;

[0024] Figure 6 It is a structural schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model;

[0025] Figure 7 This is a structural schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0028] Figure 2 : is a schematic diagram of the structure of an overvoltage detection circuit provided by an embodiment of the utility model, such as Figure 2 As shown, the overvoltage detection circuit includes: a varistor MOV1, a voltage detection module 1, a control module 2 and a prompt module 3.

[0029] The varistor MOV1 is connected in series between the two power supply terminals of the power supply to be detected, and the voltage detection module 1 is connected to the varistor MOV1 to generate a detection signal according to the voltage on the varistor MOV1;

[0030] The control module 2 is connected to the voltage detection module 1 and the prompt module 3 respectively. When an overvoltage occurs in the power supply to be detected, the control module 2 drives the prompt module 3 to issue a prompt according to the detection signal.

[0031] Specifically, the overvoltage condition of the power supply to be detected may be a condition where a voltage signal of the power supply to be detected suddenly changes significantly, for example, may include an overvoltage condition caused by a lightning strike.

[0032] When the peak value of the voltage signal on the varistor MOV1 is greater than the threshold voltage of the varistor MOV1, that is, the power supply to be detected is over-voltage, the varistor MOV1 presents a low-resistance state. When the peak value of the voltage signal on the varistor MOV1 is less than or equal to the threshold voltage of the varistor MOV1, that is, the power supply to be detected is not over-voltage, the varistor MOV1 presents a high-resistance state.

[0033] The voltage detection module 1 can generate a detection signal according to the voltage on the varistor MOV1, and the detection signal can be, for example, a voltage signal. When the power supply to be detected is over-voltage or not over-voltage, the varistor MOV1 presents different resistance states, which can be a high resistance state or a low resistance state. When the varistor MOV1 presents different resistance states, the voltage on the varistor MOV1 is different, and accordingly, the detection signal generated by the voltage detection module 1 can be different.

[0034] Further, the detection signal may include a first detection signal and a second detection signal. When the peak value of the voltage signal on the varistor MOV1 is greater than the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is overvoltage, the varistor MOV1 is in a low-resistance state, and the voltage detection module 1 generates a first detection signal. When the peak value of the voltage signal on the varistor MOV1 is less than or equal to the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is not overvoltage, the varistor MOV1 is in a high-resistance state, and the voltage detection module 1 generates a second detection signal. Among them, the first detection signal and the second detection signal are different. Exemplarily, when the first detection signal is a high-level signal, the second detection signal is a low-level signal. When the first detection signal is a low-level signal, the second detection signal is a high-level signal. The embodiments of the utility model are all described by taking the first detection signal as a low-level signal and the second detection signal as a high-level signal as an example. The voltage detection module 1 can be various circuit structures with the above functions.

[0035] Optionally, the control module 2 may include a microcontroller. Exemplarily, the control module 2 may include a single chip microcomputer, a digital signal processor (DSP) or a field programmable gate array (FPGA).

[0036] Optionally, the control module 2 may also be a driving circuit. Exemplarily, the control module 2 may include a driving transistor to convert the detection signal output by the voltage detection module 1 into a driving signal. Specifically, the control module 2 may output a stable driving voltage, which may be a DC voltage for driving the light emitting diode (prompt module) to emit a light prompt.

[0037] In some embodiments, the control module 2 is used to determine whether the power supply to be detected is over-voltage based on the first detection signal and the second detection signal. When the control module 2 determines that the detection signal output by the voltage detection module 1 is the first detection signal, the control module 2 determines that the power supply to be detected is over-voltage. When the control module 2 determines that the detection signal output by the voltage detection module 1 is the second detection signal, the control module 2 determines that the power supply to be detected is not over-voltage, that is, it is a normal situation.

[0038] In some embodiments, when the voltage detection module 2 outputs a first detection signal, the control module 2 drives the prompt module 3 to send a prompt signal according to the first detection signal, and the user determines that the power to be detected has an overvoltage when the prompt module 3 sends a prompt signal. When the voltage detection module 2 outputs a second detection signal, the control module 2 does not drive the prompt module 3 to send a prompt signal according to the second detection signal, and the user determines that the power to be detected has an undervoltage when the prompt module 3 does not send a prompt signal. Exemplarily, the control module 2 includes an N-type semiconductor driver device, and when the power to be detected has an overvoltage, that is, when the voltage detection module 2 outputs the first detection signal, the control module 2 is turned on and drives the prompt module 3 to send a prompt signal. When the power to be detected does not have an overvoltage, that is, when the voltage detection module 2 outputs the second detection signal, the control module 2 is turned off and does not drive the prompt module 3 to send a prompt signal.

[0039] The prompt module 3 can remind the user of the overvoltage of the AC power supply in the form of hearing, vision or hearing plus vision. Exemplarily, the prompt module 3 includes a display module and / or a voice prompt module, and the display module and the voice prompt module are respectively connected to the control module 2. Optionally, the display module includes a display screen or an indicator light. The voice prompt module includes a buzzer. In the embodiment of the utility model, the prompt module 3 includes a display module, that is, the prompt module 3 includes a display screen and an indicator light. Exemplarily, when the control module 2 determines that the power supply to be detected is overvoltage, the control module 2 can send a prompt instruction, which can be sent to the display screen, and then the user can be reminded that the power supply to be detected has an overvoltage risk. For example, the control module 2 can send a prompt instruction to the display screen, and the display screen can display a warning message "Warning: The current power supply to be detected has an overvoltage situation, please stay away from the power supply to be detected" according to the prompt instruction. The warning message can be expressed in a variety of forms, such as appearing in the form of a dialog box or in the form of a scroll bar.

[0040] Optionally, the overvoltage detection circuit further includes a fuse F1, which is connected in series with the varistor MOV1, and the fuse F1 is blown when the current signal of the power supply to be detected has an overcurrent.

[0041] Specifically, the fuse F1 may include a fuse. The first end of the fuse F1 is used to connect the first power supply terminal L of the power supply to be detected, such as the phase line terminal, the second end of the fuse F1 is connected to the first end of the varistor MOV1, and the second end of the varistor MOV1 is used to connect the second power supply terminal N of the power supply to be detected, such as the neutral line terminal. The input end of the voltage detection module 1 is connected to the common end A1 of the varistor MOV1 and the fuse F1.

[0042] by Figure 2 Taking the circuit structure shown in the figure as an example, the specific working principle of the overvoltage detection circuit provided in this embodiment is as follows:

[0043] When the peak value of the voltage signal of the power supply to be detected is greater than the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is overvoltage, the varistor MOV1 presents a low resistance state, and the voltage detection module 1 can output a first detection signal.

[0044] When the peak value of the voltage signal of the power supply to be detected is less than or equal to the threshold voltage of the varistor MOV1, that is, when the power supply to be detected does not exceed the voltage, the varistor MOV1 is in a high-resistance state, and the voltage detection module 1 can output a second detection signal.

[0045] In some embodiments, when the voltage detection module 2 outputs a first detection signal, the control module 2 drives the prompt module 3 to send a prompt signal according to the first detection signal, and the user determines that the power supply to be detected has an overvoltage when the prompt module 3 sends a prompt signal. When the voltage detection module 2 outputs a second detection signal, the control module 2 does not drive the prompt module 3 to send a prompt signal according to the second detection signal, and the user determines that the power supply to be detected has an undervoltage when the prompt module 3 does not send a prompt signal.

[0046] In some embodiments, the control module 2 can determine whether the input power supply to be detected is overvoltage by determining whether the output signal of the voltage detection module 1 is the first detection signal. That is, when the control module 2 determines that the detection signal is the first detection signal, the control module 2 determines that the power supply to be detected is overvoltage. When the control module 2 determines that the detection signal is the second detection signal, the control module 2 determines that the power supply to be detected is not overvoltage, which is a normal situation.

[0047] When the control module 2 determines that the power supply to be detected has an overvoltage condition, the control module 2 can send a prompt instruction, which can be sent to the prompt module 3, thereby reminding the user of the risk of overvoltage in the power supply to be detected. Moreover, since the prompt module 3 is connected to the output end of the control module 2, the output end of the control module 2 outputs a stable voltage signal. Therefore, compared with the prior art in which the signal indicator light is directly connected between the phase line and the neutral line of the AC power supply, the overvoltage detection circuit of the utility model connects the prompt module 3 to the output end of the control module 2, and the prompt module 3 is not easily damaged by the power supply to be detected, and the prompt signal of the prompt module is stable. For example, when the prompt module includes a display screen or an indicator light, the brightness of the module 30 is provided to be stable, and no light or screen flickering effect will be produced.

[0048] The overvoltage detection circuit provided by the embodiment of the utility model includes a varistor, a voltage detection module, a control module and a prompt module. The output end of the control module can output a stable voltage signal. Therefore, compared with the prior art in which the signal indicator light is directly connected between the phase line and the neutral line of the AC power supply, by connecting the prompt module to the output end of the control module, the prompt module is not easily damaged by the AC voltage signal, and the prompt signal of the prompt module is stable. In other words, the overvoltage detection circuit provided by the embodiment of the utility model can stably and reliably remind the user of the overvoltage risk, thereby improving the user experience.

[0049] Based on the above embodiments, continue to refer to Figure 2 In some embodiments, the control module 2 is used to determine whether the power supply to be detected is overvoltage based on the level duration of the first detection signal and the second detection signal. Specifically, when the control module 2 determines that the detection signal output by the voltage detection module 1 is the first detection signal, and the level duration of the first detection signal is less than the set duration, the control module 2 determines that the power supply to be detected is overvoltage. When the control module 2 determines that the detection signal output by the voltage detection module 1 is the second detection signal, and the level duration of the second detection signal is less than the set duration, the control module 2 determines that the power supply to be detected is not overvoltage. Among them, the set duration is the critical duration of the overvoltage detection circuit failure. When the level duration of the detection signal is less than the set duration, the overvoltage detection circuit has not failed. When the level duration of the detection signal is less than the set duration, the overvoltage detection circuit has failed. This embodiment does not impose any limitation on the specific value of the set duration. Exemplarily, the set duration can be 1 minute.

[0050] In some embodiments, the overvoltage detection circuit failure includes a short circuit of the varistor MOV1. The control module 2 is further configured to determine that the varistor MOV1 is short-circuited when it is determined that the detection signal output by the voltage detection module 1 is the first detection signal and the level duration of the first detection signal is greater than or equal to the set duration, and control the prompt module 3 to issue a fault prompt.

[0051] Specifically, when the varistor MOV1 is short-circuited, the common terminal A1 of the fuse F1 and the varistor MOV1 is pulled down to a low potential, and at this time, the output terminal of the voltage detection module 1 continues to output the first detection signal. In other words, when the level duration of the first detection signal output by the voltage detection module 1 is greater than or equal to the set duration, the control module 2 determines that the varistor MOV1 is short-circuited, and at this time, the control module 2 can control the prompt module 3 to issue a fault prompt.

[0052] It should be noted that the overvoltage duration of the power supply to be detected is different, and the level duration of the first detection signal is different. Similarly, the duration of the power supply to be detected without overvoltage is different, and the level duration of the second detection signal is different. Exemplarily, when the peak value of the voltage signal on the varistor MOV1 is greater than the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is overvoltage, the level duration of the first detection signal is the first duration. When the peak value of the voltage signal on the varistor MOV1 is less than or equal to the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is not overvoltage, the level duration of the second detection signal is the second duration. In other words, the size of the first duration and the second duration is related to the specific overvoltage situation of the power supply to be detected. When the overvoltage time of the power supply to be detected is relatively long, the first duration is relatively long, and when the overvoltage time of the AC voltage is relatively short, the first duration is relatively short. Similarly, when the normal time of the power supply to be detected is relatively long, the second duration is relatively long, and when the normal time of the power supply to be detected is relatively short, the second duration is relatively short. Therefore, the size of the first duration and the second duration can be the same or different.

[0053] Figure 3 FIG. 1 is a schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model. Figure 3 As shown, optionally, the voltage detection module 1 includes a voltage dividing unit 10, a first switch unit 11 and a second switch unit 12 which are connected in sequence.

[0054] The voltage dividing unit 10 is used for dividing the voltage on the varistor MOV1 and outputting the voltage to the first switch unit 11 .

[0055] The first switch unit 11 is turned on or off according to the divided voltage of the varistor MOV1 ; the second switch unit 12 is turned on when the first switch unit 11 is turned off, and is turned off when the first switch unit 11 is turned on.

[0056] Specifically, the input end of the voltage divider unit 10 is connected to the common end A1 of the varistor MOV1 and the fuse F1. When the peak value of the voltage signal of the power supply to be detected is greater than the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is over-voltage, the varistor MOV1 is in a low-resistance state, and the voltage divider unit 10 outputs a first level voltage. When the peak value of the voltage signal of the power supply to be detected is less than or equal to the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is not over-voltage, the varistor MOV1 is in a high-resistance state, and the voltage divider unit 10 outputs a second level voltage. The first switch unit 11 is used to turn off according to the first level voltage and turn on according to the second level voltage. When the first switch unit 11 and the second switch unit 12 are both N-type semiconductor switch elements, the first level voltage is less than the second level voltage. When the first switch unit 11 and the second switch unit 12 are both P-type semiconductor switch elements, the first level voltage is greater than the second level voltage. The illustrations of the subsequent embodiments are all illustrated by taking the N-type semiconductor switch element as an example.

[0057] The overvoltage detection circuit of this embodiment is provided with two switch units, which can prevent the control module 2 from being burned out when the first switch unit 11 is short-circuited, compared with the case where only one switch unit is provided. Specifically, when the voltage detection module 1 only includes the voltage dividing unit 10 and the first switch unit 11, that is, at this time, the first end of the first switch unit 11 is connected to the control module 2 and connected to the first power supply terminal VDD1. When the first switch unit 11 is short-circuited, that is, the voltage of the power supply to be detected is directly transmitted to the control module 2, and the control module 2 may be burned out. The voltage detection module of this embodiment includes the voltage dividing unit 10, the first switch unit 11 and the second switch unit 12. When the first switch unit 11 is short-circuited, the second switch unit 12 is turned on, that is, the voltage at the output end of the voltage detection module is pulled down to a low potential. At this time, the high voltage on the power supply to be detected can be prevented from being directly transmitted to the control module 2 through the short-circuited first switch unit 11, so that the control module 2 is burned out.

[0058] by Figure 3 Taking the circuit structure shown in the figure as an example, the specific working principle of the overvoltage detection circuit provided in this embodiment is as follows:

[0059] When the peak value of the voltage signal on the varistor MOV1 is greater than the threshold voltage of the varistor MOV1, the varistor MOV1 is in a low resistance state, and the voltage divider unit 10 outputs a first level voltage. When the peak value of the voltage signal on the varistor MOV1 is less than or equal to the threshold voltage, the varistor MOV1 is in a high resistance state, and the voltage divider unit 10 outputs a second level voltage.

[0060] When the voltage dividing unit 10 outputs a first level voltage, the first switch unit 11 is turned off, the second switch unit 12 is turned on, and the first end of the second switch unit 12 is pulled down to the ground potential. At this time, the output end of the voltage detection module 1 outputs a first detection signal.

[0061] When the voltage dividing unit 10 outputs the second level voltage, the first switch unit 11 is turned on, the second switch unit 12 is turned off, and the first end of the second switch unit 12 is pulled up to a high potential. At this time, the output end of the voltage detection module 1 outputs a second detection signal.

[0062] When the control module 2 determines that the detection signal is the first detection signal, and the level duration of the first detection signal is less than the set duration, the control module 2 determines that the power supply to be detected is over-voltage. When the control module 2 determines that the detection signal is the second detection signal, and the level duration of the second detection signal is less than the set duration, the control module 2 determines that the power supply to be detected is not over-voltage, that is, it is a normal situation. When the control module 2 determines that the power supply to be detected is over-voltage, the control module 2 can send a prompt instruction, which can be sent to the prompt module 3, and then the user can be reminded of the risk of over-voltage of the power supply to be detected.

[0063] As an optional implementation provided in this embodiment, Figure 4 A schematic diagram of another overvoltage detection circuit provided by the present utility model, combined with Figure 3 and Figure 4 The voltage dividing unit 10 includes an anti-reverse diode D1 and a voltage dividing sub-unit 100 .

[0064] The positive electrode of the anti-reverse diode D1 is connected to the varistor MOV1, and the negative electrode of the anti-reverse diode D1 is connected in series with the voltage divider unit 100 and grounded.

[0065] Specifically, the voltage divider unit 100 includes a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The first end of the fifth resistor R5 is connected to the cathode of the anti-reverse diode D1, the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the control end of the first switch unit 11, the first end of the seventh resistor R7 is connected to the second end of the sixth resistor R6, and the second end of the seventh resistor R7 is grounded. Optionally, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7 are current limiting resistors.

[0066] Based on the above embodiment, optionally, continue to refer to Figure 4, the first switch unit 11 includes a first transistor T1, and the second switch unit 12 includes a second transistor T2. The control end of the first transistor T1 is connected to the output end of the voltage dividing unit 10, the first end of the first transistor T1 is connected to the control end of the second transistor T2, the second end of the first transistor T1 is grounded, and the first transistor T1 is used to be turned off according to a first level voltage and turned on according to a second level voltage; the first level voltage is less than the second level voltage.

[0067] A first end of the second transistor T2 is connected to the control module 2 and to the first power supply terminal VDD1 , and a second end of the second transistor T2 is grounded.

[0068] Specifically, the first transistor T1 and the second transistor T2 may be field effect transistors or insulated gate bipolar transistors. In some embodiments, the first transistor T1 and the second transistor T2 have the same channel type. Exemplarily, the first transistor T1 and the second transistor T2 may both be P-channel transistors, and the first transistor T1 and the second transistor T2 may both be N-channel transistors. Figure 4 The case where both the first transistor T1 and the second transistor T2 are N-channel transistors is schematically shown.

[0069] The overvoltage detection circuit provided in the present embodiment controls the on and off of the first transistor T1 and the second transistor T2 by dividing the voltage levels on the first power supply terminal L and the second power supply terminal N of the power supply to be detected, and by setting the channel types of the first transistor T1 and the second transistor T2 to be the same, the control terminal of the second transistor T2 is connected to the first terminal of the first transistor T1, so that the on logic of the first transistor T1 and the second transistor T2 can be opposite, that is, the first transistor T1 and the second transistor T2 constitute a NOT gate, so that the level voltage output by the voltage dividing unit 10 can be flipped and transmitted to the control module 2 for signal processing.

[0070] On the basis of the above embodiments, optionally, referring to 4, the first switch unit 11 further includes a first capacitor C1, a first end of the first capacitor C1 is connected to the control end of the first transistor T1, and a second end of the first capacitor T1 is grounded.

[0071] Specifically, the first capacitor C1 can filter and adjust the trigger time of the first transistor T1. The larger the capacitance of the first capacitor C1, the longer the trigger time of the first transistor T1. The trigger time of the first transistor T1 represents the time required for the voltage at the control terminal of the first transistor T1 to rise from 0 to the threshold voltage of the first transistor T1.

[0072] Based on the above embodiments, optionally, referring to 4, the second switch unit 12 further includes a first resistor R1 and a second resistor R2 connected in series between the second power supply terminal VDD2 and the ground. The common end of the first resistor R1 and the second resistor R2 is connected to the control end of the second transistor T2.

[0073] The first resistor R1 and the second resistor R2 are DC bias resistors of the second transistor T2 to provide a suitable static operating point for the second transistor, thereby ensuring the operating stability of the second transistor T2.

[0074] by Figure 4 Taking the circuit structure shown in the figure as an example, the specific working principle of the overvoltage detection circuit provided in this embodiment is as follows:

[0075] When the peak value of the voltage signal on the varistor MOV1 is greater than the threshold voltage of the varistor MOV1, the varistor MOV1 is in a low-resistance state, the anti-reverse diode D1 is turned off, and the voltage divider unit 10 outputs a first-level voltage. When the peak value of the voltage signal on the varistor MOV1 is less than or equal to the threshold voltage, the varistor MOV1 is in a high-resistance state, the anti-reverse diode D1 is turned on, and the voltage divider unit 10 outputs a second-level voltage.

[0076] When the voltage dividing unit 10 outputs the first level voltage, the first transistor T1 is turned off, the second transistor T2 is turned on, and the first end of the second transistor T2 is pulled down to the ground potential, that is, the output end of the voltage detection module 1 outputs the first detection signal.

[0077] When the voltage dividing unit 10 outputs the second level voltage, the first transistor T1 is turned on, the second transistor T2 is turned off, and the first end of the second transistor T2 is pulled up to a high potential, that is, the output end of the voltage detection module 1 outputs a second detection signal.

[0078] When the control module 2 determines that the detection signal is the first detection signal, and the level duration of the first detection signal is less than the set duration, the control module 2 determines that the power supply to be detected is over-voltage. When the control module 2 determines that the detection signal is the second detection signal, and the level duration of the second detection signal is less than the set duration, the control module 2 determines that the power supply to be detected is not over-voltage, that is, it is a normal situation. When the control module 2 determines that the power supply to be detected is over-voltage, the control module 2 can send a prompt instruction, which can be sent to the prompt module 3, and then the user can be reminded of the risk of over-voltage of the power supply to be detected.

[0079] Figure 5 FIG. 1 is a schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model. Figure 5Optionally, the overvoltage detection circuit further includes an isolation module 4 , the voltage detection module 1 is connected to the control module 2 through the isolation module 4 , and the detection signal is converted by the isolation module 4 and transmitted to the control module 2 .

[0080] Based on the above embodiments, continue to refer to Figure 5 Optionally, the voltage detection module 1 is used to output a first detection signal when the power supply to be detected is over-voltage, and to output a second detection signal when the power supply to be detected is not over-voltage.

[0081] The isolation module 4 is used to output a first isolation signal corresponding to the first detection signal, and output a second isolation signal corresponding to the second detection signal. The control module 2 is used to determine whether the power supply to be detected is overvoltage according to the level duration of the first isolation signal and the level duration of the second isolation signal.

[0082] Specifically, the first isolation signal is the first detection signal isolated by the isolation module 4, and the second isolation signal is the second detection signal isolated by the isolation module 4. The larger the value of the first detection signal, the larger the value of the first isolation signal, and the smaller the value of the first detection signal, the smaller the value of the first isolation signal. Similarly, the larger the value of the second detection signal, the larger the value of the second isolation signal, and the smaller the value of the second detection signal, the larger the value of the second isolation signal.

[0083] Optionally, when the control module 2 determines that the isolation signal output by the isolation module 4 is a first isolation signal, and the level duration of the first isolation signal is less than a set duration, the control module 2 determines that the power supply to be detected is overvoltage. When the control module 2 determines that the isolation signal output by the isolation module 4 is a second isolation signal, and the level duration of the second isolation signal is less than a set duration, the control module 2 determines that the power supply to be detected is not overvoltage.

[0084] The overvoltage duration of the power supply to be detected is different, and the level duration of the first isolation signal is different. Similarly, the duration of the power supply to be detected without overvoltage is different, and the level duration of the second isolation signal is different. Exemplarily, when the peak value of the voltage signal on the varistor MOV1 is greater than the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is overvoltage, the level duration of the first isolation signal is the first duration. When the peak value of the voltage signal on the varistor MOV1 is less than or equal to the threshold voltage of the varistor MOV1, that is, when the power supply to be detected is not overvoltage, the level duration of the second isolation signal is the second duration. In other words, the size of the first duration and the second duration is related to the specific overvoltage situation of the power supply to be detected. When the overvoltage time of the power supply to be detected is relatively long, the first duration is relatively long, and when the overvoltage time of the AC voltage is relatively short, the first duration is relatively short. Similarly, when the normal time of the power supply to be detected is relatively long, the second duration is relatively long, and when the normal time of the power supply to be detected is relatively short, the second duration is relatively short. Therefore, the size of the first duration and the second duration can be the same or different. In this embodiment, the voltage detection module 1 is isolated from the control module 2 by the isolation module 4, so as to improve the stability of the detection signal output by the voltage detection module 1, and further improve the anti-interference capability of the overvoltage detection circuit.

[0085] Figure 6 FIG. 1 is a schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model. Figure 6 Optionally, the isolation module 4 includes an optocoupler isolator U1, a third resistor R3 and a fourth resistor R4.

[0086] The first end I1 of the third resistor R3 is connected to the second power supply terminal VDD2, and the second end I2 of the third resistor R3 is connected to the first end I1 of the optocoupler isolator U1. The second end I2 of the optocoupler isolator U1 is connected to the output end of the voltage detection module 1, the third end I3 of the optocoupler isolator U1 is grounded, and the fourth end I4 of the optocoupler isolator U1 is connected to the control module 2; the first end of the fourth resistor R4 is connected to the first power supply terminal VDD1, and the second end of the fourth resistor R4 is connected to the control module 2.

[0087] Figure 7 FIG. 1 is a schematic diagram of another overvoltage detection circuit provided by an embodiment of the utility model. Figure 7 The overvoltage detection circuit includes: a varistor MOV1, a voltage detection module 1, a control module 2 and a prompt module 3.

[0088] Optionally, the voltage detection module 1 includes a voltage dividing unit 10, a first switch unit 11 and a second switch unit 12. The voltage dividing unit 10 includes an anti-reverse diode S1 and a voltage dividing subunit 100. The voltage dividing subunit 100 includes a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7.

[0089] Optionally, the first switch unit 11 includes a first transistor T1, and the second switch unit 12 includes a second transistor T2. Optionally, the first switch unit 11 also includes a first capacitor C1.

[0090] Optionally, the second switch unit 12 further includes a first resistor R1 and a second resistor R2.

[0091] Optionally, the overvoltage detection circuit further includes an isolation module 4 , and the isolation module 4 includes an optocoupler isolator U1 , a third resistor R3 , and a fourth resistor R4 .

[0092] by Figure 7 Taking the circuit structure shown in the figure as an example, the specific working principle of the overvoltage detection circuit provided in this embodiment is as follows:

[0093] When the peak value of the voltage signal on the varistor MOV1 is greater than the threshold voltage of the varistor MOV1, the varistor MOV1 is in a low-resistance state, the anti-reverse diode D1 is turned off, and the voltage divider unit 10 outputs a first-level voltage. When the peak value of the voltage signal on the varistor MOV1 is less than or equal to the threshold voltage, the varistor MOV1 is in a high-resistance state, the anti-reverse diode D1 is turned on, and the voltage divider unit 10 outputs a second-level voltage.

[0094] When the voltage divider unit 10 outputs the first level voltage, the first transistor T1 is turned off, the second transistor T2 is turned on, and the first end of the second transistor T2 is pulled down to the ground potential. At this time, the output end of the voltage detection module 1 outputs the first detection signal. The optocoupler isolator U1 is turned on, and at this time, the optocoupler isolator U1 outputs a corresponding first isolation signal according to the first detection signal.

[0095] When the voltage divider unit 10 outputs the second level voltage, the first transistor T1 is turned on, the second transistor T2 is turned off, and the first end of the second transistor T2 is pulled up to a high potential, and at this time the output end of the voltage detection module 1 outputs a second detection signal. The optocoupler isolator U1 is not turned on, and at this time the fourth end I4 of the optocoupler isolator U1 is pulled up to a high potential on the first power supply end by the fourth resistor R4, that is, at this time the isolation module 4 outputs a corresponding second isolation signal according to the second detection signal.

[0096] When the control module 2 determines that the isolation signal is the first isolation signal, and the level duration of the first isolation signal is less than the set duration, the control module 2 determines that the power supply to be detected is over-voltage. When the control module 2 determines that the isolation signal is the second isolation signal, and the level duration of the second isolation signal is less than the set duration, the control module 2 determines that the power supply to be detected is not over-voltage, that is, it is a normal situation. When the control module 2 determines that the power supply to be detected is over-voltage, the control module 2 can send a prompt instruction, which can be sent to the prompt module 3, and then the user can be reminded of the risk of over-voltage of the power supply to be detected.

[0097] When the varistor MOV1 is short-circuited, the common terminal A1 of the fuse F1 and the varistor MOV1 is pulled down to a low potential, and the anti-reverse diode D1 is turned off at this time, that is, the voltage divider unit 10 continuously outputs the first level voltage. When the voltage divider unit 10 continuously outputs the first level voltage, the first transistor T1 is always turned off, the second transistor T2 is always turned on, and the first end of the second transistor T2 is continuously pulled down to the ground potential, that is, the output end of the voltage detection module 1 continuously outputs the first detection signal, and at this time, the optocoupler isolator U1 is always turned on, and the potential of the fourth terminal I4 of the optocoupler isolator U1 is continuously pulled down to a low potential, that is, the fourth terminal I4 of the optocoupler isolator U1 continuously outputs the first isolation signal. When the control module 2 detects that the fourth terminal I4 of the optocoupler isolator U1 continuously outputs the first isolation signal, the control module 2 determines that the varistor MOV1 is short-circuited, and at this time, the control module 2 can control the prompt module 3 to issue a fault prompt. That is to say, when the control module 2 determines that the isolation signal is the first isolation signal, and the level duration of the first isolation signal is greater than or equal to the set duration, the control module 2 determines that the varistor MOV1 is short-circuited. At this time, the control module 2 can control the prompt module 3 to issue a fault prompt.

[0098] Based on the same utility model concept, the utility model also provides an electronic device, which includes the overvoltage detection circuit provided by any of the above embodiments, and has the functional modules and beneficial effects of any of the above embodiments, which will not be described in detail in this embodiment. For example, the electronic device can be an adapter, a fast charger, a power strip, etc., and the utility model embodiment does not specifically limit this.

[0099] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. An overvoltage detection circuit, characterized in that: include: Varistor, voltage detection module, control module and prompt module; The varistor is connected in series between two power supply terminals of the power supply to be detected, and the voltage detection module is connected to the varistor and is used to generate a detection signal according to the voltage on the varistor; The control module is connected to the voltage detection module and the prompt module respectively. When the power supply to be detected has an overvoltage, the control module drives the prompt module to issue a prompt according to the detection signal.

2. The overvoltage detection circuit according to claim 1, characterized in that: The voltage detection module includes a voltage dividing unit, a first switch unit and a second switch unit connected in sequence; The voltage divider unit is used to divide the voltage on the varistor and output it to the first switch unit; the first switch unit is turned on or off according to the voltage division of the varistor; the second switch unit is turned on when the first switch unit is turned off, and is turned off when the first switch unit is turned on.

3. The overvoltage detection circuit according to claim 2, characterized in that: The voltage dividing unit comprises an anti-reverse diode and a voltage dividing sub-unit; The positive electrode of the anti-reverse diode is connected to the varistor, and the negative electrode of the anti-reverse diode is connected in series with the voltage divider unit and grounded.

4. The overvoltage detection circuit according to claim 2, characterized in that: The first switch unit includes a first transistor, and the second switch unit includes a second transistor; The control terminal of the first transistor is connected to the output terminal of the voltage dividing unit, the first terminal of the first transistor is connected to the control terminal of the second transistor, the second terminal of the first transistor is grounded, and the first transistor is used to be turned off according to a first level voltage and turned on according to a second level voltage; The first level voltage is lower than the second level voltage; A first end of the second transistor is connected to the control module and to a first power supply end, and a second end of the second transistor is grounded.

5. The overvoltage detection circuit according to claim 4, characterized in that: The first switch unit further includes a first capacitor; a first end of the first capacitor is connected to the control end of the first transistor, and a second end of the first capacitor is grounded.

6. The overvoltage detection circuit according to claim 4, characterized in that: The second switch unit further includes a first resistor and a second resistor connected in series between a second power supply terminal and ground, and a common terminal of the first resistor and the second resistor is connected to the control terminal of the second transistor.

7. The overvoltage detection circuit according to claim 1, characterized in that: It also includes an isolation module, through which the voltage detection module is connected to the control module, and the detection signal is converted by the isolation module and then transmitted to the control module.

8. The overvoltage detection circuit according to claim 7, characterized in that: The voltage detection module is used to output a first detection signal when the power supply to be detected is over-voltage, and to output a second detection signal when the power supply to be detected is not over-voltage; The isolation module is used to output a corresponding first isolation signal according to the first detection signal, and to output a corresponding second isolation signal according to the second detection signal; The control module is used to determine whether the power supply to be detected is overvoltage according to the level duration of the first isolation signal and the level duration of the second isolation signal.

9. The overvoltage detection circuit according to claim 7, characterized in that: The isolation module includes an optocoupler isolator, a third resistor and a fourth resistor; The first end of the third resistor is connected to the second power supply end, and the second end of the third resistor is connected to the first end of the optical coupler isolator; The second end of the optocoupler isolator is connected to the output end of the voltage detection module, the third end of the optocoupler isolator is grounded, and the fourth end of the optocoupler isolator is connected to the control module; A first end of the fourth resistor is connected to the first power supply end, and a second end of the fourth resistor is connected to the control module.

10. The overvoltage detection circuit according to claim 1, characterized in that: It also includes a fuse, which is connected in series with the varistor and blows when the current signal of the power supply to be detected is overcurrent; The control module is also used to determine that the varistor is short-circuited and control the prompt module to issue a fault prompt when it is determined that the detection signal output by the voltage detection module is a first detection signal and the level duration of the first detection signal is greater than or equal to a set duration.

11. The overvoltage detection circuit according to claim 1, characterized in that: The prompt module includes a display screen or an indicator light.

12. An electronic device, characterized in that: The invention comprises the overvoltage detection circuit as described in any one of claims 1 to 11.

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