Hysteresis circuit, emergency lighting circuit and lighting equipment

Abstract

The present application discloses a hysteresis circuit, an emergency lighting circuit and a lighting device. The hysteresis circuit includes: a voltage detection module, which is used to receive an input voltage, generate a sampling voltage according to the input voltage, and detect the sampling voltage; an isolation coupling module, which is used to control the output signal of the isolation coupling module according to the sampling voltage; a voltage adjustment module, which is used to adjust the sampling voltage; the hysteresis circuit of the present application detects the sampling voltage associated with the input voltage, and when it is detected that the sampling voltage drops to the trigger action voltage point, the level corresponding to the control output signal is reversed, until it is detected that the sampling voltage rises to the reverse recovery voltage point, the level corresponding to the control output signal is reversed again, thereby realizing timely and accurate judgment of the input voltage state, so as to further improve the reliability and safety of the product.

Description

Technical Field

[0001] The present application relates to the technical field of lighting circuits, and in particular to a hysteresis circuit, an emergency lighting circuit and a lighting device. Background Art

[0002] Lighting that is activated when the power supply to normal lighting fails is called emergency lighting. Emergency lighting is different from ordinary lighting. It includes three types: backup lighting, evacuation lighting, and safety lighting. Emergency lighting is an important safety facility in modern public buildings and industrial buildings, and is closely related to personal safety and building safety. When a fire or other disaster occurs in a building and the power supply is interrupted, emergency lighting plays an important role in personnel evacuation, fire rescue work, and the continued operation of important production and work or necessary operations.

[0003] At present, the fire emergency lighting and evacuation indication system includes the power supply of emergency lighting fixtures and evacuation indicator fixtures. For the non-centrally controlled emergency lighting centralized power supply, there are the following regulations: when the main power supply voltage of the lamp is working at any voltage within the range of 60%-80% of its rated voltage, the status indicator light and relay of the emergency lighting centralized power supply should not switch multiple times. If multiple switching occurs, it will cause the main power supply voltage of the lamp to have inevitable ripples and instability.

[0004] Therefore, relevant technical personnel proposed Figure 1 The scheme shown is used to determine the main power supply voltage of the lamp. Figure 1 As shown, for a non-isolated power supply, the ADC sampling value is obtained by using the single-chip microcomputer U4, and the following logical judgment is performed: judging whether the input voltage Vbus reaches the trigger action voltage point, and when returning to normal operation, judging whether the input voltage Vbus reaches the reverse recovery voltage point. The trigger action voltage point refers to the voltage value corresponding to the preset function (for example, triggering the emergency function), and the reverse recovery voltage point refers to the voltage value corresponding to the return to the preset function (for example, returning to normal operation).

[0005] However, the above solution has its specific limitations, including: 1) it is only suitable for non-isolated power supplies, whose input voltage and microcontroller share a common ground, and is suitable for applications with relatively broad requirements for product safety design; 2) it is only suitable for circuits with microcontroller control and suitable ADC sampling value detection ports.

[0006] Therefore, it is necessary to propose solutions to the existing technical problems. Summary of the invention

[0007] The purpose of the present application is to provide a hysteresis circuit, an emergency lighting circuit and a lighting device, which are designed to detect a sampling voltage associated with an input voltage, and when it is detected that the sampling voltage drops to a trigger action voltage point, the level corresponding to the control output signal is flipped, until it is detected that the sampling voltage rises to a reverse recovery voltage point, the level corresponding to the control output signal is flipped again, thereby realizing timely and accurate monitoring of the input voltage state, so as to further improve the reliability and safety of the product.

[0008] According to one aspect of the present application, an embodiment of the present application provides a hysteresis circuit, which includes: a voltage detection module, used to receive an input voltage, generate a sampling voltage according to the input voltage, and detect the sampling voltage; an isolation coupling module, used to control the output signal of the isolation coupling module according to the sampling voltage; a voltage adjustment module, used to adjust the sampling voltage; wherein, when the voltage detection module detects that the sampling voltage is less than a first set value, the optical coupler in the isolation coupling module is controlled to be in an isolation state, so that the output signal of the isolation coupling module is a first level signal, and the voltage adjustment module starts to adjust the sampling voltage; when the detection voltage detects that the sampling voltage is greater than a second set value, the optical coupler is controlled to be in a coupling state, so that the output signal of the isolation coupling module is a second level signal, and the voltage adjustment module stops adjusting the sampling voltage, wherein the second set value is greater than the first set value, and the difference between the two is greater than a preset threshold, and the first level signal is different from the second level signal.

[0009] Optionally, the voltage detection module includes: a first voltage-dividing resistor, a second voltage-dividing resistor, a first capacitor and a voltage regulator; wherein the first end of the first voltage-dividing resistor receives the input voltage, the second end of the first voltage-dividing resistor is connected to the first end of the second voltage-dividing resistor and forms a first node, and the first voltage-dividing resistor and the second voltage-dividing resistor are used to divide the input voltage so that the voltage of the first node is a sampling voltage; the first end of the second voltage-dividing resistor is electrically connected to the first end of the first capacitor and the first pin of the voltage regulator, respectively, and the second end of the second voltage-dividing resistor is electrically connected to the second end of the first capacitor and the third pin of the voltage regulator, respectively; the first end of the first capacitor is electrically connected to the first pin of the voltage regulator, and the second end of the first capacitor is electrically connected to the third pin of the voltage regulator; the second pin of the voltage regulator is connected to the isolation coupling module, the third pin of the voltage regulator is connected to the power ground, and the first pin of the voltage regulator is used to obtain the sampling voltage.

[0010] Optionally, when the sampled voltage obtained by the first pin of the voltage regulator is less than a first set value, the voltage regulator is in a cut-off state; when the sampled voltage obtained by the first pin of the voltage regulator is greater than a second set value, the voltage regulator is in a conduction state.

[0011] Optionally, the isolation coupling module also includes: a fifth resistor and a sixth resistor; the first end of the fifth resistor receives the first side power supply voltage, and the second end of the fifth resistor is electrically connected to the positive electrode of the light-emitting diode on the primary side of the optocoupler; the first end of the sixth resistor is connected to the second side power supply voltage, and the second end of the sixth resistor is electrically connected to the collector of the transistor on the secondary side of the optocoupler; the cathode of the light-emitting diode on the primary side of the optocoupler is electrically connected to the second pin of the regulator in the voltage detection module, and the emitter of the transistor on the secondary side of the optocoupler is connected to the signal ground.

[0012] Optionally, the voltage adjustment module includes: a first voltage regulator tube, a seventh resistor, an eighth resistor, a ninth resistor and a first switching tube; wherein, the first end of the first voltage regulator tube is electrically connected to the first end of the seventh resistor, and the second end of the first voltage regulator tube is electrically connected to the second end of the fifth resistor in the isolation coupling module; the second end of the seventh resistor is electrically connected to the first end of the eighth resistor and the control end of the first switching tube respectively; the first end of the eighth resistor is electrically connected to the control end of the first switching tube, and the second end of the eighth resistor is electrically connected to the first end of the first switching tube; the first end of the ninth resistor is electrically connected to the first end of the second voltage-dividing resistor in the voltage detection module, and the second end of the ninth resistor is electrically connected to the second end of the first switching tube; the first end of the first switching tube is respectively connected to the second end of the second voltage-dividing resistor in the voltage detection module and the power ground.

[0013] Optionally, the second voltage-dividing resistor in the voltage detection module and the ninth resistor in the voltage adjustment module are variable resistors.

[0014] Optionally, the first set value may be configured to be associated with the resistance value of the second voltage-dividing resistor; and the second set value may be configured to be associated with the resistance value of the ninth resistor.

[0015] Optionally, a power ground to which the primary side of the optocoupler is connected through a voltage regulator in the voltage detection module and a signal ground to which the secondary side of the optocoupler is connected are not in common ground.

[0016] According to another aspect of the present application, an embodiment of the present application provides an emergency lighting circuit, which includes: a rectifier circuit for converting input alternating current into direct current to provide direct current to the hysteresis circuit; the hysteresis circuit described in any embodiment of the present application; and a control circuit for controlling whether an indicator light or a relay is working according to an output signal of an isolation coupling module in the hysteresis circuit.

[0017] According to another aspect of the present application, an embodiment of the present application provides a lighting device, and the lighting device includes the emergency lighting circuit described in any embodiment of the present application.

[0018] The hysteresis circuit, emergency lighting circuit and lighting equipment described in the embodiments of the present application are intended to detect a sampling voltage associated with the input voltage. When it is detected that the sampling voltage has dropped to a trigger action voltage point, the level corresponding to the control output signal is flipped, until it is detected that the sampling voltage has risen to a reverse recovery voltage point, the level corresponding to the control output signal is flipped again, so as to realize a hysteresis design for input voltage detection, thereby realizing timely and accurate monitoring of the input voltage state, and further ensuring that the emergency lighting circuit works according to the specified requirements and improving the reliability and safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0020] Figure 1 It is a schematic diagram of a hysteresis circuit in the prior art.

[0021] Figure 2 A schematic diagram of the structure of a hysteresis circuit provided in one embodiment of the present application.

[0022] Figure 3 A circuit diagram of a hysteresis circuit provided in accordance with an embodiment of the present application.

[0023] Figure 4 A schematic diagram of an emergency lighting circuit provided in accordance with an embodiment of the present application.

[0024] Figure 5 A schematic diagram of a lighting device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0026] The terms "first" and "second" in this document are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0027] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0029] Figure 2 A schematic diagram of the structure of a hysteresis circuit provided in one embodiment of the present application.

[0030] See also Figure 2As shown, an embodiment of the present application provides a hysteresis circuit 1000, the hysteresis circuit 1000 includes: a voltage detection module 110, used to receive an input voltage Vbus, and generate a sampling voltage VA according to the input voltage Vbus, and detect the sampling voltage VA; an isolation coupling module 120, used to control the output signal Vbus_c of the isolation coupling module 120 according to the sampling voltage; a voltage adjustment module 130, used to adjust the sampling voltage VA; wherein, when the voltage detection module 110 detects that the sampling voltage VA is less than a first set value, the optical coupler in the isolation coupling module 120 is controlled U1 is in an isolated state, so that the output signal Vbus_c of the isolation coupling module 120 is a first level signal, and the voltage adjustment module 130 starts to adjust the sampling voltage VA; when the detection voltage detects that the sampling voltage VA is greater than a second set value, the optical coupler U1 is controlled to be in a coupled state, so that the output signal Vbus_c of the isolation coupling module 120 is a second level signal, and the voltage adjustment module 130 stops adjusting the sampling voltage VA, wherein the second set value is greater than the first set value, and the difference between the two is greater than a preset threshold, and the first level signal is different from the second level signal.

[0031] Such a design can realize the hysteresis design of input voltage detection, so that the state of input voltage can be judged timely and accurately, and it can also ensure that the corresponding emergency lighting circuit works normally according to the specified requirements, so as to improve the reliability and safety of lighting equipment.

[0032] The following will be combined Figure 3 The structure of the hysteresis circuit 1000 is further described.

[0033] See also Figure 2 and Figure 3 As shown, an embodiment of the present application provides a hysteresis circuit 1000 , which includes: a voltage detection module 110 , an isolation coupling module 120 and a voltage adjustment module 130 .

[0034] Specifically, the voltage detection module 110 may include: a first voltage-dividing resistor and a second voltage-dividing resistor, a first capacitor C1 and a voltage regulator U2. The first end of the first voltage-dividing resistor receives the input voltage, the second end of the first voltage-dividing resistor is connected to the first end of the second voltage-dividing resistor and forms a first node A, and the first voltage-dividing resistor and the second voltage-dividing resistor are used to divide the input voltage so that the voltage of the first node A is the sampling voltage. In this embodiment, the first voltage-dividing resistor may include a first resistor R1, a second resistor R2, and a third resistor R3, but in other embodiments, the first voltage-dividing resistor may include multiple resistors or only one resistor. The second voltage-dividing resistor is a fourth resistor R4 (hereinafter described as the fourth resistor). Figure 2 As shown, specifically, the first end of the first resistor R1 receives the input voltage Vbus, and the second end of the first resistor R1 is electrically connected to the first end of the second resistor R2. The second end of the second resistor R2 is electrically connected to the first end of the third resistor R3, and the second end of the third resistor R3 is electrically connected to the first end of the fourth resistor R4, the first end of the first capacitor C1 and the first pin of the voltage regulator U2. The first end of the fourth resistor R4 is electrically connected to the first end of the first capacitor C1 and the first pin of the voltage regulator U2, respectively, and the second end of the fourth resistor R4 is electrically connected to the second end of the first capacitor C1 and the third pin of the voltage regulator U2. The first end of the first capacitor C1 is electrically connected to the first pin of the voltage regulator U2, and the second end of the first capacitor C1 is electrically connected to the third pin of the voltage regulator U2. The second pin of the voltage regulator U2 is connected to the isolation coupling module 120, and the third pin of the voltage regulator U2 is connected to the power ground.

[0035] In the voltage detection module 110, the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are connected in series in sequence. The first resistor R1 receives an input voltage Vbus. The input voltage Vbus can be a DC voltage, which can be obtained through the action of a rectifier circuit in the emergency lighting circuit. In this embodiment, the resistance values ​​of the first resistor R1, the second resistor R2 and the third resistor R3 are the same, and are different from the fourth resistor R4. The fourth resistor R4 and the above three resistors (the first resistor R1, the second resistor R2, the third resistor R3) divide the input voltage to obtain a sampling voltage VA of the first node A. Figure 3As shown, the voltage of the first node A is the sampling voltage VA, and the same applies to the following. At the same time, the voltage obtained by the first pin of the voltage regulator U2 is the sampling voltage VA. When the sampling voltage obtained by the first pin of the voltage regulator U2 is less than the first set value, the voltage regulator U2 is in the cut-off state; when the sampling voltage obtained by the first pin of the voltage regulator U2 is greater than the second set value, the voltage regulator U2 is in the on state. Therefore, the voltage regulator U2 can be regarded as a switching element.

[0036] Furthermore, the first capacitor C1 is connected in parallel with the fourth resistor R4, and is used to filter the voltage signal received by the first pin of the voltage regulator U2. In this embodiment, the voltage regulator U2 can be a TL431M type voltage regulator, and the internal reference voltage of the voltage regulator U2 is 2.5 V. If other types of voltage regulators are used, their internal reference voltages may be different.

[0037] The isolation coupling module 120 includes: a fifth resistor R5, a sixth resistor R6 and an optocoupler U1. The first end of the fifth resistor R5 receives the first side power supply voltage VF, and the second end of the fifth resistor R5 is electrically connected to the positive electrode of the light-emitting diode on the primary side of the optocoupler U1. The first end of the sixth resistor R6 is connected to the second side power supply voltage VDD, and the second end of the sixth resistor R6 is electrically connected to the collector of the transistor on the secondary side of the optocoupler U1. The cathode of the light-emitting diode on the primary side of the optocoupler U1 is electrically connected to the second pin of the voltage regulator U2 in the voltage detection module 110, and the emitter of the transistor on the secondary side of the optocoupler U1 is connected to the signal ground.

[0038] In this embodiment, the optical coupler U1 adopts an EL817 optical coupler, but is not limited thereto. When the light emitting diode on the primary side of the optical coupler U1 is turned on, the triode on the secondary side works normally, so that the optical coupler U1 is in a coupled state. When the light emitting diode on the primary side of the optical coupler U1 is turned off, the triode on the secondary side does not work, so that the optical coupler U1 is in an isolated state.

[0039] It should be noted that the first side power supply voltage VF received by the first end of the fifth resistor R5 and the second side power supply voltage VDD received by the first end of the sixth resistor R6 are both fixed power supply voltages. In addition, in this embodiment, the power ground connected to the primary side of the optical coupler U1 through the voltage regulator U2 in the voltage detection module 110 and the signal ground connected to the secondary side of the optical coupler U1 are not common grounds. Of course, in other embodiments, the power ground and the signal ground can be common grounds (applicable to non-isolated power supplies).

[0040] Continue reading Figure 2 and Figure 3, the voltage adjustment module 130 includes: a first voltage regulator tube ZD1, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a first switch tube Q1. Among them, the first end of the first voltage regulator tube ZD1 is electrically connected to the first end of the seventh resistor R7, and the second end of the first voltage regulator tube ZD1 is electrically connected to the second end of the fifth resistor R5 in the isolation coupling module 120. The second end of the seventh resistor R7 is electrically connected to the first end of the eighth resistor R8 and the control end of the first switch tube Q1 respectively. The first end of the eighth resistor R8 is electrically connected to the control end of the first switch tube Q1, and the second end of the eighth resistor R8 is electrically connected to the first end of the first switch tube Q1. The first end of the ninth resistor R9 is electrically connected to the first end of the fourth resistor R4 in the voltage detection module 110, and the second end of the ninth resistor R9 is electrically connected to the second end of the first switch tube Q1. The first end of the first switch tube Q1 is respectively connected to the second end of the fourth resistor R4 in the voltage detection module 110 and the power ground.

[0041] In this embodiment, the ninth resistor R9 is connected in series with the first switch tube Q1 and then connected in parallel with the fourth resistor R4. When the first switch tube Q1 is in the on state, its on-resistance is connected in series with the ninth resistor R9 and then connected in parallel with the fourth resistor R4. When the first switch tube Q1 is in the off state, its resistance is very large, and after being connected in series with the ninth resistor R9, the influence on the resistance of the fourth resistor R4 in parallel can be ignored. In other words, when the first switch tube Q1 is in the on state, the resistance to ground of the first pin of the voltage regulator U2 is the equivalent resistance corresponding to the parallel connection of the fourth resistor R4, the ninth resistor R9 and the on-resistance of the first switch tube Q1, and when the first switch tube Q1 is in the off state, the resistance of the first switch tube Q1 is very large, so the resistance to ground of the first pin of the voltage regulator U2 is the fourth resistor R4. In this way, the resistance of the first pin of the voltage regulator U2 to ground when the first switch tube Q1 is turned on is smaller than the resistance of the first pin of the voltage regulator U2 to ground when the first switch tube Q1 is turned off.

[0042] Optionally, in this embodiment, the fourth resistor R4 in the voltage detection module 110 and the ninth resistor R9 in the voltage adjustment module 130 are variable resistors. When the input voltage remains unchanged and the resistance of the fourth resistor R4 increases, the sampling voltage VA increases. When the input voltage remains unchanged and the resistance of the fourth resistor R4 decreases, the sampling voltage VA decreases. Further, when the first switch tube Q1 is in the on state, when the resistance of the ninth resistor R9 increases, the hysteresis voltage decreases. When the resistance of the ninth resistor R9 decreases, the hysteresis voltage increases, and the hysteresis voltage will be further explained below. Therefore, the first set value (i.e., the trigger voltage action point) can be configured to be associated with the resistance of the fourth resistor, and the second set value (i.e., the reverse recovery voltage point) can be configured to be associated with the resistance of the ninth resistor.

[0043] The working principle of the hysteresis circuit 1000 will be further described below.

[0044] When the input voltage Vbus is different, the sampling voltage VA changes accordingly. If the input voltage is higher, the sampling voltage VA is higher, and if the input voltage is lower, the sampling voltage VA is lower.

[0045] If the input voltage Vbus decreases and gradually decreases to the following situation: when the sampling voltage VA is less than the internal reference voltage of the voltage regulator U2, the sampling voltage VA reaches the trigger voltage action point (i.e., the first set value), and the voltage regulator U2 enters the cut-off state, so the light-emitting diode on the primary side of the optocoupler U1 is not conducting (i.e., the cut-off state), so that the optocoupler U1 is in an isolated state. When the optocoupler U1 is in the isolated state, the output signal Vbus_c of the isolation coupling module 120 is a first level signal. In this embodiment, the first level signal is a high level. At the same time, since the light-emitting diode on the primary side of the optocoupler U1 is in the cut-off state, that is, Figure 3 The first pin of the optical coupler U1 is at a high level, so the first switch tube Q1 is in an on state, so that its on resistance is connected in series with the ninth resistor R9 and in parallel with the fourth resistor R4, so that the sampling voltage VA is reduced.

[0046] If the input voltage Vbus increases from the original decrease and gradually increases, when the input voltage Vbus returns to the original input voltage, since the on-resistance of the first switch tube Q1 is connected in series with the ninth resistor R9 and then in parallel with the fourth resistor R4, the sampling voltage VA is still less than the internal reference voltage of the regulator U2.

[0047] Then, the input voltage Vbus continues to increase, and when it increases to the following situation: when the sampling voltage VA is greater than the internal reference voltage of the voltage regulator U2, the sampling voltage VA reaches the reverse recovery voltage point (i.e., the second set value), and the voltage regulator U2 enters the on state, so the light-emitting diode on the primary side of the optocoupler U1 is in the on state, so that the optocoupler U1 is in the coupled state. When the optocoupler U1 is in the coupled state, the output signal Vbus_c of the isolation coupling module 120 changes from the first level signal to the second level signal. In this embodiment, the second level signal is a low level signal, which is different from the first level signal. If the first level signal is a high level signal and the second level signal is a low level signal, the two signals are opposite signals. Therefore, the output signal Vbus_c of the isolation coupling module 120 changes from a high level to a low level. At the same time, since the light-emitting diode on the primary side of the optocoupler U1 is in the on state, that is, Figure 3 The first pin of the optical coupler U1 is at a low level, so the first switch tube Q1 is in a cut-off state. In this way, the resistance of the first switch tube Q1 is very large. After being connected in series with the ninth resistor R9, the influence on the resistance of the fourth resistor R4 in parallel can be ignored, so that the sampling voltage VA increases. Therefore, it can be further ensured that the sampling voltage VA is greater than the internal reference voltage of the regulator U2, so that the output signal Vbus_c of the isolation coupling module 120 remains a low level signal.

[0048] It should be noted that the second set value is greater than the first set value, and the difference between the second set value and the first set value is greater than a preset threshold value, wherein the preset threshold value is related to the resistance of the ninth resistor R9 and the first switch tube Q1 in the voltage adjustment module 130. Therefore, the voltage value corresponding to the reverse recovery voltage point is greater than the voltage value corresponding to the trigger action voltage point. Further, the trigger action voltage point (i.e., the point corresponding to the action voltage) is related to the resistance of the fourth resistor R4. The reverse recovery voltage point (i.e., the point corresponding to the hysteresis voltage) is related to the resistance of the ninth resistor R9 and the first switch tube Q1. When the first switch tube Q1 is in the on state, when the resistance of the ninth resistor R9 increases, the hysteresis voltage decreases. When the resistance of the ninth resistor R9 decreases, the hysteresis voltage increases.

[0049] In the hysteresis circuit 1000 described in any embodiment of the present application, a trigger action voltage point and a reverse recovery voltage point with a certain voltage difference are set to implement a hysteresis design for input voltage detection, so that the state of the input voltage can be judged timely and accurately, and further, the corresponding emergency lighting circuit can be guaranteed to work normally under the specified requirements, and the reliability and safety of the product can be improved.

[0050] In addition, in the hysteresis circuit 1000 described in any embodiment of the present application, since the power ground connected to the primary side of the optocoupler U1 through the regulator U2 in the voltage detection module 110 and the signal ground connected to the secondary side of the optocoupler U1 are not common grounds, the hysteresis circuit 1000 can be applied to an isolated power supply, and there is no need to use a single-chip microcomputer to detect the sampling value, so that the hysteresis circuit 1000 described in the present application has a wider range of applications.

[0051] Based on the same inventive concept, an embodiment of the present application further provides an emergency lighting circuit.

[0052] See also Figure 4 As shown, the emergency lighting circuit 2000 includes: a rectifier circuit 1100 , a hysteresis circuit 1000 and a control circuit 1200 .

[0053] Specifically, the rectifier circuit 1100 is used to convert input alternating current into direct current to provide direct current to the hysteresis circuit 1000 .

[0054] The hysteresis circuit is the hysteresis circuit 1000 described in any of the above embodiments, and its specific structure and working principle are as described above, which will not be repeated here.

[0055] The control circuit 1200 is used to control whether an indicator light (not shown) or a relay (not shown) is working according to the output signal Vbus_c of the isolation coupling module 120 in the hysteresis circuit 1000 .

[0056] When it is determined that the voltage value corresponding to the output signal Vbus_c is less than the preset threshold value, the control state indicator light or relay works; when it is determined that the voltage value corresponding to the output signal Vbus_c is greater than or equal to the preset threshold value, the control state indicator light or relay stops working. Among them, the state indicator light or relay is connected to the control circuit 1200. In this embodiment, when it is determined that the output signal Vbus_c is a low-level signal, the control state indicator light is in a lit state, or the control relay enters a working state. When it is determined that the output signal Vbus_c is a high-level signal, the control state indicator light is in an off state, or the control relay stops working.

[0057] As described in the background art, when the main power supply voltage of the lamp is operated at any voltage within the range of 60%-80% of its rated voltage, the status indicator light and relay of the emergency lighting centralized power supply should not switch multiple times. If multiple switching occurs, the main power supply voltage of the lamp will inevitably have ripples and instability. Therefore, the present application provides an emergency lighting circuit 2000, which adopts the hysteresis circuit 1000 described above to detect and control the main power supply voltage (i.e., input voltage) of the lamp.

[0058] In the process of the main power supply voltage decreasing to 60% to 80% of the rated voltage (i.e., the input voltage Vbus of the lamp is decreased from 100% of the rated voltage to 60%-80% of the rated voltage), the sampling voltage VA in the hysteresis circuit 1000 decreases accordingly with the decrease of the input voltage, and when the trigger action voltage point is reached, the voltage regulator U2 is in the cut-off state, and the corresponding optical coupler U1 is in the isolation state, so that the output signal Vbus_c of the isolation coupling module 120 is a high-level signal. Since the output signal Vbus_c of the isolation coupling module 120 is a high-level signal (i.e., the output signal of the hysteresis circuit is a high-level signal), the status indicator light connected to the control circuit 1200 in the emergency lighting circuit 2000 is in an off state, or the relay connected to the control circuit 1200 stops working, and accordingly, the lamp connected to the relay does not work either, for example, the lamp is in an off state.

[0059] In the process that the main power supply voltage rises to more than 80% of the rated voltage (i.e., the input voltage Vbus of the lamp rises from 60%-80% of the rated voltage to more than 80% of the rated voltage), the sampling voltage in the hysteresis circuit 1000 rises accordingly with the rise of the input voltage, and when the reverse recovery voltage point is reached, the voltage regulator U2 is in the on state, and the corresponding optical coupler U1 is in the on state, so that the output signal Vbus_c of the isolation coupling module 120 is a low-level signal. Since the output signal Vbus_c of the isolation coupling module 120 is a low-level signal (i.e., the output signal of the hysteresis circuit is a low-level signal), the status indicator light connected to the control circuit 1200 in the emergency lighting circuit 2000 is in the on state, and at the same time, the relay connected to the control circuit 1200 starts to work, and accordingly, the lamp connected to the relay enters the working state, for example, the lamp is in the on state.

[0060] Since a trigger action voltage point and a reverse recovery voltage point with a certain voltage difference are set in the hysteresis circuit 1000, the state of the input voltage can be judged timely and accurately, thereby ensuring that the corresponding emergency lighting circuit 2000 works normally under the specified requirements (that is, when the main power supply voltage drops to 60%-80% of its rated voltage, the status indicator light or relay does not work, and when the main power supply voltage rises to greater than 80% of the rated voltage, the status indicator light or relay enters the working state), which can improve the reliability and safety of the lamp.

[0061] Based on the same inventive concept, an embodiment of the present application further provides a lighting device.

[0062] See also Figure 5As shown, the lighting device 5000 includes the above-mentioned emergency lighting circuit 2000. The lighting device 5000 can be an emergency lighting centralized power supply or a self-powered lamp. In some embodiments, the emergency lighting centralized power supply is a non-centrally controlled emergency lighting centralized power supply. In other embodiments, the automatic power supply type lamp is a self-powered non-centrally controlled lamp. When the main power supply voltage of these devices is reduced to a range of 60%-80% of its rated voltage, the status indicator light or relay does not work, and when the main power supply voltage of these devices rises to greater than 80% of the rated voltage, the status indicator light or relay enters a working state, thereby improving the safety and reliability of the lighting device.

[0063] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0064] The above is a detailed introduction to a hysteresis circuit, an emergency lighting circuit and a lighting device provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A hysteresis circuit, characterized in that: The hysteresis circuit comprises: A voltage detection module, configured to receive an input voltage, generate a sampling voltage according to the input voltage, and detect the sampling voltage; An isolation coupling module, used for controlling an output signal of the isolation coupling module according to the sampling voltage; A voltage adjustment module, used for adjusting the sampling voltage; Wherein, when the voltage detection module detects that the sampling voltage is less than a first set value, the optical coupler in the isolation coupling module is controlled to be in an isolation state, so that the output signal of the isolation coupling module is a first level signal, and the voltage adjustment module starts to adjust the sampling voltage; when the detection voltage detects that the sampling voltage is greater than a second set value, the optical coupler is controlled to be in a coupling state, so that the output signal of the isolation coupling module is a second level signal, and the voltage adjustment module stops adjusting the sampling voltage, wherein the second set value is greater than the first set value, and the difference between the two is greater than a preset threshold, and the first level signal is different from the second level signal; The voltage detection module includes: a first voltage-dividing resistor, a second voltage-dividing resistor, a first capacitor and a voltage regulator; the first end of the first voltage-dividing resistor receives the input voltage, the second end of the first voltage-dividing resistor is connected to the first end of the second voltage-dividing resistor and forms a first node, the first voltage-dividing resistor and the second voltage-dividing resistor are used to divide the input voltage so that the voltage of the first node is a sampling voltage, the first end of the second voltage-dividing resistor is electrically connected to the first end of the first capacitor and the first pin of the voltage regulator, respectively, and the second end of the second voltage-dividing resistor is electrically connected to the second end of the first capacitor and the third pin of the voltage regulator, respectively; the first end of the first capacitor is electrically connected to the first pin of the voltage regulator, and the second end of the first capacitor is electrically connected to the third pin of the voltage regulator; the second pin of the voltage regulator is connected to the isolation coupling module, the third pin of the voltage regulator is connected to the power ground, and the first pin of the voltage regulator is used to obtain the sampling voltage; The isolation coupling module further includes: a fifth resistor and a sixth resistor; the first end of the fifth resistor receives the first side power supply voltage, and the second end of the fifth resistor is electrically connected to the positive electrode of the light-emitting diode on the primary side of the optical coupler; the first end of the sixth resistor is connected to the second side power supply voltage, and the second end of the sixth resistor is electrically connected to the collector of the triode on the secondary side of the optical coupler; the cathode of the light-emitting diode on the primary side of the optical coupler is electrically connected to the second pin of the voltage regulator in the voltage detection module, and the emitter of the triode on the secondary side of the optical coupler is connected to the signal ground; The voltage adjustment module includes: a first voltage regulator tube, a seventh resistor, an eighth resistor, a ninth resistor and a first switch tube; wherein the first end of the first voltage regulator tube is electrically connected to the first end of the seventh resistor, and the second end of the first voltage regulator tube is electrically connected to the second end of the fifth resistor in the isolation coupling module; the second end of the seventh resistor is electrically connected to the first end of the eighth resistor and the control end of the first switch tube respectively; the first end of the eighth resistor is electrically connected to the control end of the first switch tube, and the second end of the eighth resistor is electrically connected to the first end of the first switch tube; the first end of the ninth resistor is electrically connected to the first end of the second voltage-dividing resistor in the voltage detection module, and the second end of the ninth resistor is electrically connected to the second end of the first switch tube; the first end of the first switch tube is respectively connected to the second end of the second voltage-dividing resistor in the voltage detection module and the power ground.

2. The hysteresis circuit according to claim 1, characterized in that: When the sampled voltage obtained by the first pin of the voltage regulator is less than a first set value, the voltage regulator is in a cut-off state; when the sampled voltage obtained by the first pin of the voltage regulator is greater than a second set value, the voltage regulator is in a conducting state.

3. The hysteresis circuit according to claim 1, characterized in that: The second voltage-dividing resistor in the voltage detection module and the ninth resistor in the voltage adjustment module are variable resistors.

4. The hysteresis circuit according to claim 3, characterized in that: The first set value may be configured to be associated with the resistance value of the second voltage-dividing resistor; the second set value may be configured to be associated with the resistance value of the ninth resistor.

5. The hysteresis circuit according to claim 1, characterized in that: The power ground to which the primary side of the optical coupler is connected through the voltage regulator in the voltage detection module and the signal ground to which the secondary side of the optical coupler is connected are not in common ground.

6. An emergency lighting circuit, characterized in that: The emergency lighting circuit comprises: A rectifier circuit, used for converting input alternating current into direct current, so as to provide direct current to the hysteresis circuit; The hysteresis circuit according to any one of claims 1 to 5; The control circuit is used to control whether the indicator light or the relay works according to the output signal of the isolation coupling module in the hysteresis circuit.

7. A lighting device, characterized in that: The lighting device comprises the emergency lighting circuit according to claim 6.

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