Emergency light circuit and lighting system

Abstract

Disclosed in the present application is a control solution for an emergency light. An alternating-current input voltage supplies power to a lighting load by means of a power supply apparatus, the power supply apparatus comprising a voltage conversion circuit and a battery, wherein the voltage conversion circuit receives the alternating-current input voltage to supply power to a light and charge the battery. In the case where there is no alternating-current input voltage, when an emergency light is required to keep lighting, power is supplied to the emergency light by means of the battery. A discharging circuit is connected to at least one input end of the alternating-current input voltage, so as to discharge the voltage of an alternating-current input end. In the present application, the voltage of an alternating-current input end is discharged by means of a discharging circuit, such that a system can accurately determine whether there is an alternating-current input, so as to control an internal battery to start emergency lighting, thereby ensuring the smooth turning-on of an emergency light in some specific occasions.

Description

Emergency lighting circuits and lighting systems

[0001] This application claims priority to a Chinese invention application filed on July 19, 2023, with application number 202310890492.5 and titled “Emergency Lighting Circuit and Lighting System,” and incorporates the entire specification, claims, drawings, and abstract of the aforementioned Chinese invention application into this application by reference. Technical Field

[0002] The present invention relates to the technical field of power electronics, and more particularly to an emergency lighting circuit and a lighting system. Background Art

[0003] Emergency lighting systems include two power supply lines for light source loads, such as LED lights: one circuit is AC input, which directly supplies power to the load through a switching converter, and the other circuit is an emergency battery. When the AC input is normal, the AC input is converted to an appropriate voltage by a switching converter, such as an ACDC converter, to supply the load. When the AC input is absent, if the impedance of the two input terminals (L / N) is less than a preset value, the emergency battery supplies power to the load. If it is greater than the preset value, the lighting system shuts down.

[0004] However, in environments with fans or elevators, input impedance misdetection may occur. This is because when the switch at the L / N terminal is disconnected due to a large generator, residual AC voltage will still exist even when there is no AC input. This residual voltage will cause the input terminal to misdetect that there is AC input, and the emergency lighting cannot be turned on, causing the load to stop working.

[0005] Therefore, it is necessary to provide an improved technical solution to overcome the above technical problems existing in the prior art. Summary of the Invention

[0006] In view of this, an object of the present invention is to provide an emergency lighting circuit and a lighting system to solve the technical problem of false detection in some environments existing in the prior art.

[0007] The present invention provides an emergency lighting circuit, wherein an AC input voltage supplies power to a lighting load through a power supply device. The circuit comprises: the power supply device including a voltage conversion circuit and a battery, the voltage conversion circuit receiving the AC input voltage to supply power to the lighting lamp and charge the battery; an emergency lighting control circuit, wherein in the absence of the AC input voltage, when the emergency lighting lamp is required to remain illuminated, the emergency lighting control circuit controls the battery to supply power to the emergency lighting lamp, the lighting load including the lighting lamp and the emergency lighting lamp, wherein the emergency lighting control circuit includes a discharge circuit, the discharge circuit being connected to an input end of the AC input voltage or an end point of the lighting load to discharge the voltage at the connection node so that the emergency lighting control circuit can determine whether the AC input voltage is present.

[0008] Preferably, the discharge circuit discharges the voltage at the AC input end with a predetermined current.

[0009] Preferably, the discharge circuit is connected to at least one input terminal of the AC input voltage to discharge the voltage of the AC input terminal.

[0010] Preferably, the emergency lighting control circuit includes an AC input detection circuit, which is connected to one input terminal of the AC input to obtain an input detection signal and compares the input detection signal with a first threshold voltage. When the input detection signal is lower than the first threshold voltage, the discharge circuit is controlled to discharge the voltage of the AC input terminal.

[0011] Preferably, when the input detection signal is higher than the first threshold voltage, the discharge circuit is controlled to stop discharging the voltage of the AC input end, and after a delay of a period of time, a timer is started. When the input detection signal is lower than the first threshold voltage or the timer reaches a preset value, the discharge circuit is controlled to discharge the voltage of the AC input end.

[0012] Preferably, the discharge circuit includes a first discharge circuit and a second discharge circuit, the first discharge circuit is connected to one input end of the AC input voltage, and the second discharge circuit is connected to the other input end of the AC input voltage.

[0013] Preferably, the first discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, or a switch tube and a current source connected in series; the second discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, or a switch tube and a current source connected in series.

[0014] Preferably, the first discharge circuit includes any one of a resistor and a current source; the second discharge circuit includes any one of a resistor and a current source.

[0015] Preferably, the power supply device further includes a high-voltage isolation circuit, and the emergency lighting control circuit includes an impedance detection circuit. The high-voltage isolation circuit is connected between the AC input terminal and the battery. When there is AC input, the circuit is used to isolate the AC input terminal and the battery. The impedance detection circuit is used to detect the impedance of the two AC input terminals to generate an impedance detection result. When there is no AC input voltage, the emergency lighting control circuit determines whether to start the battery to power the emergency lighting lamp based on the impedance detection result.

[0016] Preferably, the impedance detection circuit obtains an input detection signal based on an input terminal connected to the AC input, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The emergency lighting control circuit includes a switch control circuit and a first switch tube. The switch control circuit receives the comparison result of the AC input detection circuit and the impedance detection result. When both are in a valid state, the switch control circuit controls the first switch tube to be turned on so that the battery can power the lighting lamp.

[0017] Preferably, the discharge circuit is connected to an end point of the lighting load to discharge the voltage at the connection node. The emergency lighting control circuit includes an impedance detection circuit, a comparison circuit, a switch control circuit, and a first switching tube. The impedance detection circuit obtains an input detection signal based on an input terminal connected to the AC input, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The comparison circuit compares the voltage at the connection node between the discharge circuit and the lighting load with a reference voltage to obtain a comparison signal. The switch control circuit receives the comparison result of the comparison signal and the impedance detection result. When both are in a valid state, the switch control circuit controls the first switching tube to be turned on so that the battery can power the lighting lamp.

[0018] In a second aspect, a lighting system is provided, comprising the above-mentioned emergency lighting circuit and a lighting load, wherein the emergency lighting circuit receives an AC input voltage to control normal lighting and emergency lighting of the lighting load.

[0019] The control scheme of the emergency lighting of the present invention discharges the residual voltage at the AC input end or the terminal voltage of the lighting load in the discharge circuit, so that the system can accurately determine whether there is AC input. In the absence of AC input, the emergency lighting is started by the built-in battery, ensuring that the emergency lighting is turned on smoothly in some specific occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a circuit block diagram of a first embodiment of an emergency lighting circuit according to the present invention;

[0021] FIG2 is a circuit block diagram of a second embodiment of an emergency lighting circuit according to the present invention;

[0022] FIG3 is a circuit block diagram of a third embodiment of an emergency lighting circuit according to the present invention;

[0023] FIG4 is a specific circuit diagram according to the embodiment of FIG2 ;

[0024] FIG5 is a detailed circuit diagram of the AC input detection circuit, the impedance detection circuit, and the switch control circuit according to the embodiment of FIG2 ;

[0025] FIG6 is a specific circuit diagram of a discharge control unit according to the embodiment of FIG3 ;

[0026] FIG7 is a circuit diagram of a first embodiment of a discharge circuit;

[0027] FIG8 is a circuit diagram of a second embodiment of a discharge circuit;

[0028] FIG9 is a circuit diagram of a third embodiment of a discharge circuit. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments and covers any substitution, modification, equivalent method and solution made within the spirit and scope of the present invention.

[0030] In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can also fully understand the present invention without description of these details.

[0031] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are simplified and not to exact proportions, and are only used for the purpose of conveniently and clearly illustrating the embodiments of the present invention.

[0032] FIG1 is a block diagram of a first embodiment of an emergency lighting circuit according to the present invention. The emergency lighting circuit of the present invention is applied to a lighting system. An AC input voltage is supplied to a lighting load via a power supply device. The power supply device includes a voltage conversion circuit and a battery. The voltage conversion circuit receives the AC input voltage to power the lighting and charge the battery. The voltage conversion circuit, exemplified by an ACDC converter, converts the AC input voltage to a desired DC power source to power the lighting when the AC input voltage is present or absent. The emergency lighting control circuit controls the battery to power the emergency lighting when the emergency lighting needs to remain illuminated in the absence of the AC input voltage. The lighting loads include lighting and emergency lighting. The emergency lighting can be part of the lighting or another lighting load. The emergency lighting control circuit includes a discharge circuit. In this example, the discharge circuit is connected to at least one input terminal of the AC input voltage to discharge the voltage at the AC input terminal. The discharge circuit can be a single discharge circuit connected to one input terminal or two discharge circuits connected to two input terminals for discharge. The voltage conversion circuit may include a rectifier circuit to rectify the AC input voltage to obtain an input DC voltage. The voltage conversion circuit may be configured to supply the DC input voltage to the battery for charging through a switch, couple the voltage to the battery for charging through a winding, or supply the output voltage to the battery for charging.

[0033] FIG1 takes a discharge circuit as an example, and FIG2 is a circuit block diagram of a second embodiment of an emergency lighting circuit according to the present invention; FIG2 takes two discharge circuits as an example, wherein the discharge circuit includes a first discharge circuit and a second discharge circuit, wherein the first discharge circuit is connected to one input terminal of the AC input voltage, and the second discharge circuit is connected to the other input terminal of the AC input voltage.

[0034] Preferably, the discharge circuit discharges the voltage at the AC input terminal with a predetermined current. For example, the discharge circuit discharges the voltage at the AC input terminal with a constant current, or alternatively, with a variable current. The predetermined current is generally set to a relatively small value to minimize excessive power consumption.

[0035] Referring to FIG4 , which is a specific circuit diagram of the embodiment in FIG2 , FIG5 , which is a specific circuit diagram of the AC input detection circuit, the impedance detection circuit, and the switch control circuit according to the embodiment in FIG2 , and FIG6 , which is a specific circuit diagram of the discharge control unit according to the embodiment in FIG3 . Referring to FIG4 and FIG5 , the discharge control unit controls the discharge on and off of the discharge circuit. The discharge control unit is connected to the input voltage detection circuit. Here, the emergency lighting control circuit includes an AC input detection circuit, which includes a detection circuit (resistors R1 and R2) and a comparator U1, where Rd is the equivalent resistance between the two input terminals. The detection circuit is connected to one input terminal of the AC input voltage to obtain an input detection signal and compares the input detection signal with a first threshold voltage Vref1. When the input detection signal is less than the first threshold voltage Vref1, the comparison result Vu1 output by the comparator U1 is in a high-level active state, and the discharge control unit initiates discharge of the discharge circuit based on the comparison result of the comparator U1. When the input detection signal is greater than the first threshold voltage Vref1, the comparison result Vu1 is in a low-level active state, and the discharge control unit turns off the discharge circuit. At this time, after a delay, a timer, such as timer 2, starts timing. When the input detection signal is lower than the first threshold voltage or the timer reaches the time, the discharge circuit is controlled to discharge the voltage of the AC input terminal. This cycle is repeated, and the preset value of timer 2 lasts for a period of time less than or equal to half a power frequency cycle, as known to those skilled in the art. Referring to Figure 6, the discharge control unit receives the comparison result Vu1 and the negative signal of the comparison result Vu1. The negative signal of the comparison result Vu1 obtains the start time of the timer after a delay, and the negative signal of the comparison result Vu1 resets the previous count of the timer. The comparison result Vu1 and the signal of timer 2 are passed through an OR gate to obtain a signal for controlling the discharge circuit.

[0036] With reference to Figures 7, 8, and 9, the discharge circuit may include a first discharge circuit or a first discharge circuit and a second discharge circuit. The first discharge circuit includes a switch tube, a resistor and a switch tube in series, such as a switch tube Q1 and a resistor R3, or a switch tube and a current source in series; the second discharge circuit includes a switch tube, a resistor and a switch tube in series, such as a switch tube Q2 and a resistor R4, or a switch tube and a current source in series. Here, the discharge condition of the discharge circuit, such as the discharge moment and the discharge duration, is controlled by the switch tube, so that the discharge can be better controlled. The switch tube can control the switching state according to the comparison result of the input voltage detection. With reference to Figure 9, the first discharge circuit includes any one of a resistor and a current source, such as a current source I1; the second discharge circuit includes any one of a resistor and a current source I2. It will be appreciated by those skilled in the art that the above-mentioned discharge circuits can all discharge the voltage at the input end with a predetermined current.

[0037] Continuing with reference to FIG5 , the power supply device further includes an impedance detection circuit, a high-voltage isolation circuit, and a switch module. The switch module includes a switch control circuit and a first switch tube S1. The impedance detection circuit includes a comparator U2 for detecting the impedance of the two AC input terminals to generate an impedance detection result. The impedance detection circuit obtains an input detection signal based on one input terminal connected to the AC input, and compares the input detection signal with a second threshold voltage Vref2 to obtain the impedance detection result Vu2. The AC input detection circuit further includes a timer 1. When the comparison result received from the comparator U1 is continuously in a low-level invalid state for a period of time, the timer 1 determines that there is no input AC voltage. The negative signal of the comparator U1 is used to reset the timer 1, and the timer 1 outputs a signal Vj to the switch control circuit. When the switch control circuit receives the output signal of timer 1 and the impedance detection result, both of which are in a valid state, the emergency lighting control circuit controls the battery to not supply power to the emergency lighting if there is no AC input voltage. If the impedance detection result is a high impedance state and the emergency lighting does not need to be activated, the emergency lighting control circuit controls the battery to supply power to the emergency lighting. If the impedance detection result is a low impedance state, indicating a power outage and the emergency lighting needs to be activated, the emergency lighting control circuit controls the battery to supply power to the emergency lighting. The switch control circuit controls the first switch S1 to conduct, and the battery supplies power to the lighting. Switch S1 is used to connect the battery and the emergency lighting load. The switch control circuit includes an AND gate, a trigger, a switch drive circuit, and a sampling circuit. When the AND gate receives the comparison result and the impedance detection result and both are in a valid state, it outputs a high-level active signal. The trigger generates a trigger signal to the switch drive circuit to control switch S1 to conduct, and the battery supplies power to the emergency lighting load. The sampling circuit provides feedback on the current level of the battery supplying the emergency lighting.

[0038] Referring to Figure 5 , the high-voltage isolation circuit is connected between the AC input terminal and the battery. When AC input is present, it isolates the connection between the AC input terminal and the battery. The high-voltage isolation circuit includes an isolation switch, which is controlled on and off based on the comparison result of the AC input detection circuit. When the comparison result indicates the absence of AC input voltage, the isolation switch is turned on. The high-voltage isolation circuit can also be a diode, which can also isolate the high-voltage input terminal from the battery.

[0039] Referring to Figure 3, a circuit block diagram of a third embodiment of an emergency lighting circuit according to the present invention is shown. The emergency lighting control circuit in this embodiment is identical to the impedance detection circuit, switch module, and high-voltage isolation module of the first embodiment and will not be further described here. The difference is that in this example, the discharge circuit is connected to the terminals of the lighting load to discharge the voltage at the connection node. The emergency lighting control circuit includes an impedance detection circuit, a comparison circuit, a switch control circuit, and a first switching transistor. The impedance detection circuit receives an input detection signal from an input terminal connected to the AC input and compares the input detection signal with a second threshold voltage to obtain an impedance detection result. The comparison circuit compares the voltage at the connection node between the discharge circuit and the lighting load with a reference voltage to obtain a comparison signal. Here, the reference voltage is the operating voltage of the connected lighting load. The switch control circuit receives the comparison result of the comparison signal and the impedance detection result. If both are valid, it controls the first switching transistor to conduct, allowing the battery to power the lighting lamp. The lighting load may include multiple LEDs, and the connected lighting load may be a partial load. In this example, the discharge circuit can be a low-current source that pulls down the voltage of the connected load. When there is no AC input voltage, the voltage at the node connecting the discharge circuit and the lighting load is less than a reference voltage. When there is AC input voltage, the voltage at the node connecting the discharge circuit and the lighting load is consistent with the reference voltage. When there is no AC input voltage but only residual voltage, the voltage at the node connecting the discharge circuit and the lighting load is also less than the reference voltage. Therefore, the presence of AC input voltage can be accurately determined, allowing the emergency lighting to be properly activated.

[0040] The present application also provides a lighting system, comprising the emergency lighting circuit and a lighting load, wherein the emergency lighting circuit receives an AC input voltage to control normal lighting and emergency lighting of the lighting.

[0041] The lighting system of the present application discharges the voltage at the AC input end or the voltage of the load through a discharge circuit. In special circumstances, such as when the AC input in an elevator is actually disconnected, the discharge circuit discharges the residual voltage of the AC input so that the system can accurately determine whether there is an AC input. In the absence of AC input, the emergency lighting is started by the built-in battery, ensuring that the emergency lighting can be turned on smoothly in some specific occasions.

[0042] It should be noted that the specific implementation and corresponding illustrations given are merely a way of describing the implementation method of the present invention, and do not limit the specific structure of the implementation scheme of the present invention. Various changes or modifications can be made to these implementation schemes without departing from the principles and essence of the present invention, but these changes and modifications fall within the scope of protection of the present invention.

[0043] Although the embodiments are described and explained separately above, some common technologies are involved. It is the opinion of ordinary technicians in this field that they can be replaced and integrated between the embodiments. If there is anything not clearly recorded in one of the embodiments, reference can be made to another recorded embodiment.

[0044] The above-described embodiments do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the above-described embodiments shall be included in the scope of protection of this technical solution.

Claims

1. An emergency lighting circuit, wherein an AC input voltage supplies power to a lighting load through a power supply device, characterized in that: include, The power supply device includes a voltage conversion circuit and a battery. The voltage conversion circuit receives the AC input voltage to power the lighting lamp and charge the battery. The emergency lighting control circuit controls the battery to supply power to the emergency lighting when the emergency lighting is required to maintain lighting in the absence of AC input voltage, wherein the lighting load includes the lighting lamp and the emergency lighting. Among them, the emergency lighting control circuit includes a discharge circuit, which is connected to the input end of the AC input voltage or the end point of the lighting load to discharge the voltage of the connection node so that the emergency lighting control circuit can determine whether there is an AC input voltage.

2. The emergency lighting circuit according to claim 1, characterized in that: The discharge circuit discharges the voltage of the AC input terminal with a predetermined current.

3. The emergency lighting circuit according to claim 1, characterized in that: The discharge circuit is connected to at least one input terminal of the AC input voltage to discharge the voltage of the AC input terminal.

4. The emergency lighting circuit according to claim 3, characterized in that: The emergency lighting control circuit includes an AC input detection circuit, The AC input detection circuit is connected to an input terminal of the AC input to obtain an input detection signal, and compares the input detection signal with a first threshold voltage. When the input detection signal is lower than the first threshold voltage, the discharge circuit is controlled to discharge the voltage of the AC input terminal.

5. The emergency lighting circuit according to claim 4, characterized in that: When the input detection signal is higher than the first threshold voltage, the discharge circuit is controlled to stop discharging the voltage of the AC input terminal. At the same time, after a delay period, a timer starts timing, and when the input detection signal is lower than the first threshold voltage or the timer reaches a preset value, the discharge circuit is controlled to discharge the voltage of the AC input terminal.

6. The emergency lighting circuit according to claim 1 or 3, characterized in that: The discharge circuit includes a first discharge circuit and a second discharge circuit, The first discharge circuit is connected to an input end of the AC input voltage, The second discharge circuit is connected to the other input end of the AC input voltage.

7. The emergency lighting circuit according to claim 6, characterized in that: The first discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, and a switch tube and a current source connected in series; The second discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, and a switch tube and a current source connected in series.

8. The emergency lighting circuit according to claim 6, characterized in that: The first discharge circuit includes any one of a resistor and a current source; The second discharge circuit includes any one of a resistor and a current source.

9. The emergency lighting circuit according to claim 3, characterized in that: The power supply device further includes a high voltage isolation circuit, and the emergency lighting control circuit includes an impedance detection circuit. The high-voltage isolation circuit is connected between the AC input terminal and the battery, and is used to isolate the AC input terminal and the battery when there is AC input. The impedance detection circuit is used to detect the impedance of the two AC input terminals to generate an impedance detection result. In the absence of an AC input voltage, the emergency lighting control circuit determines whether to start the battery to supply power to the emergency lighting lamp according to the impedance detection result.

10. The emergency lighting circuit according to claim 9, characterized in that: The impedance detection circuit obtains an input detection signal by connecting an input terminal of the AC input, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The emergency lighting control circuit includes a switch control circuit and a first switch tube. The switch control circuit receives a comparison result of the AC input detection circuit and the impedance detection result. When both are in a valid state, the first switch tube is controlled to be turned on so that the battery can power the lighting lamp.

11. The emergency lighting circuit according to claim 1, characterized in that: The discharge circuit is connected to the end point of the lighting load to discharge the connection node voltage. The emergency lighting control circuit includes an impedance detection circuit, a comparison circuit, a switch control circuit and a first switch tube. The impedance detection circuit obtains an input detection signal by connecting an input terminal of the AC input, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The comparison circuit compares the voltage at the connection node between the discharge circuit and the lighting load with a reference voltage to obtain a comparison signal. The switch control circuit receives a comparison result of the comparison signal and the impedance detection result, and when both are in a valid state, controls the first switch tube to be turned on so that the battery supplies power to the lighting lamp.

12. A lighting system, characterized in that: The emergency lighting circuit and lighting load according to any one of claims 1 to 11 are included. The emergency lighting circuit receives an AC input voltage to control normal lighting and emergency lighting of the lighting load.

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