Lighting circuit and lighting device

Abstract

The objective of this disclosure is to suppress the degradation of storage batteries. [Solution] The control power supply circuit 14 generates a control power supply voltage V5 to operate the control circuit 13. The switching circuit 15 opens and closes the first path LN1 that inputs DC power from the storage battery 20 to the input section 140 of the control power supply circuit 14. The switching circuit 15 is configured to open and close the first path LN1 by the drive voltage V3 output from the control circuit 13. The control circuit 13 outputs a drive voltage V3 to the switching circuit 15 to close the path when the supply of AC power (output voltage V2) from the normal power supply P1 stops. The control circuit 13 stops outputting the drive voltage V3 and opens the first path LN1 when the battery voltage V6 of the storage battery 20 reaches a predetermined threshold.

Description

【Technical Field】 【0001】 The present disclosure relates to a lighting circuit and a lighting device, and more particularly, to a lighting circuit that performs emergency lighting using a storage battery, and a lighting device including the lighting circuit. 【Background Art】 【0002】 As a conventional example, a lighting device (lighting circuit) described in Patent Document 1 is exemplified. The lighting device described in Patent Document 1 (hereinafter referred to as the conventional example) receives power supply from an AC power source such as a commercial power source during normal times and generates DC power to be supplied to a light source circuit. Further, in the conventional example, during an emergency such as a power outage, power is received from a storage battery and DC power to be supplied to the light source circuit is generated. The storage battery is charged by the power supplied from the AC power source via a charging circuit during normal times. The power charged in the storage battery is used to light a light source during an emergency. 【0003】 The conventional example also has a microcomputer and two control power supply circuits that supply a control power supply to the microcomputer. The microcomputer operates a DC-DC conversion circuit to light the light source circuit and operates a charging circuit to charge the storage battery during normal times, and operates another DC-DC conversion circuit connected to the storage battery to continuously light the light source circuit during an emergency. One of the two control power supply circuits generates DC power supply power for operating the microcomputer using AC power supplied from the AC power source during normal times. The other of the two control power supply circuits generates DC power supply power for operating the microcomputer during an emergency. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2012-003991 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 By the way, in the conventional example described above, if the AC power supply is not restored during an emergency, the light source circuit will continue to light up until the electrical energy stored in the battery is completely used up. 【0006】 However, if the light source circuit is kept lit until all the electrical energy stored in the battery is used up, as in the conventional example above, it may cause the battery to over-discharge, which could accelerate its deterioration. 【0007】 The purpose of this disclosure is to provide a lighting circuit and lighting device that can suppress the degradation of storage batteries. [Means for solving the problem] 【0008】 A lighting circuit according to one aspect of the present disclosure comprises an AC / DC conversion circuit, a charging circuit, an adjustment circuit, a control circuit, a control power supply circuit, and a switching circuit. The AC / DC conversion circuit converts AC power supplied from a normal power supply into DC power. The charging circuit charges a storage battery with the DC power. The adjustment circuit adjusts the DC power and the DC power output from the storage battery and supplies them to a lighting load. The control circuit controls the AC / DC conversion circuit, the charging circuit, and the adjustment circuit. The control power supply circuit generates a control power supply voltage for operating the control circuit. The switching circuit opens and closes a path for inputting DC power from the storage battery to the input of the control power supply circuit. The switching circuit is configured to open and close the path by a drive voltage output from the control circuit. The control circuit outputs the drive voltage to the switching circuit to close the path when the supply of AC power from the normal power supply is stopped. The control circuit stops outputting the drive voltage and opens the path when the battery voltage of the storage battery reaches a predetermined threshold. 【0009】 A lighting device according to one aspect of the present disclosure comprises a lighting circuit and a lighting load that is lit by DC power supplied from the adjustment circuit of the lighting circuit. [Effects of the Invention] 【0010】 The lighting circuit and lighting device disclosed herein have the effect of suppressing the degradation of the storage battery. [Brief explanation of the drawing] 【0011】 [Figure 1] Figure 1 is a partially abbreviated circuit diagram of a lighting circuit and lighting device according to an embodiment of this disclosure. [Figure 2] Figure 2 is a front view of the same lighting device. [Figure 3] Figure 3 is a side view of the same lighting device. [Figure 4] Figure 4 is a time chart illustrating the operation of the lighting circuit shown above. [Modes for carrying out the invention] 【0012】 The lighting circuit and lighting device according to the embodiments of this disclosure will be described in detail with reference to the drawings. However, the figures described in the embodiments below are schematic diagrams, and the ratios of the size and thickness of each component do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of this disclosure. This disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of this disclosure can be achieved. 【0013】 (1) Overview The lighting circuit B1 according to this embodiment includes an AC / DC conversion circuit 10, a charging circuit 11, an adjustment circuit 12, a control circuit 13, a control power supply circuit 14, and a switching circuit 15 (see Figure 1). 【0014】 The AC / DC conversion circuit 10 converts AC power supplied from the regular power supply P1 into DC power. The regular power supply P1 is, for example, a commercial power grid. The AC / DC conversion circuit 10 consists of a full-wave rectifier, a smoothing capacitor, a DC conversion circuit, and the like. 【0015】 The charging circuit 11 charges the battery 20 with DC power. The charging circuit 11 is, for example, a constant current circuit. The adjustment circuit 12 adjusts the DC power output from the AC / DC conversion circuit 10 and the DC power output from the battery 20 and supplies them to the lighting load 21. The adjustment circuit 12 is, for example, a boost chopper circuit. The adjustment circuit 12 adjusts the output current by PWM control of the switching elements of the boost chopper circuit. 【0016】 The control circuit 13 controls the AC / DC conversion circuit 10, the charging circuit 11, and the adjustment circuit 12. The control circuit 13 mainly consists of a microcontroller. The control power supply circuit 14 generates the control power supply voltage V5 to operate the control circuit 13. The switch circuit 15 opens and closes the path (first path LN1) for inputting DC power from the storage battery 20 to the input section 140 of the control power supply circuit 14. 【0017】 Furthermore, the switching circuit 15 is configured to close the first path LN1 by a drive voltage V3 output from the control circuit 13. The control circuit 13 outputs a drive voltage V3 to the switching circuit 15 to close the first path LN1 when the supply of AC power from the normal power supply P1 is stopped. The control circuit 13 stops outputting the drive voltage V3 and opens the first path LN1 when the battery voltage V6 of the storage battery 20 reaches a predetermined threshold. 【0018】 However, in the embodiment, when AC power is supplied from the normal power supply P1, the lighting circuit B1 uses the DC power output from the AC / DC conversion circuit 10 to generate the control power supply voltage V5 in the control power supply circuit 14. Also, in the embodiment, when AC power is not supplied from the normal power supply P1, the lighting circuit B1 uses the DC power output (discharged) from the storage battery 20 to generate the control power supply voltage V5 in the control power supply circuit 14. Therefore, even when AC power is not supplied from the normal power supply P1, the lighting circuit B1 in the embodiment can use the DC power output from the storage battery 20 to allow the control circuit 13 to continue controlling the adjustment circuit 12. 【0019】 Furthermore, when the lighting circuit B1 according to the embodiment supplies power from the storage battery 20 to the control power supply circuit 14, when the battery voltage V6 of the storage battery 20 reaches a predetermined threshold value, the control circuit 13 stops the output of the drive voltage V3 and releases the first path LN1 in the opening / closing circuit 15. 【0020】 Therefore, the lighting circuit B1 according to the embodiment can prevent the storage battery 20 from being over-discharged and can suppress the deterioration of the storage battery 20. 【0021】 (2) Details Next, the lighting circuit B1 according to the embodiment (hereinafter abbreviated as the lighting circuit B1), and the lighting device A1 according to the embodiment (hereinafter abbreviated as the lighting device A1) will be described in more detail with reference to the drawings. 【0022】 (2-1) Lighting device First, the lighting device A1 will be described with reference to FIGS. 2 - 3. 【0023】 The lighting device A1 is, for example, an emergency lighting device directly attached to the ceiling in the passage of the common area of an apartment building. However, the lighting device A1 may be directly attached to the wall. Alternatively, the lighting device A1 may be a staircase passage guiding light installed in an evacuation passage such as a fire staircase. 【0024】 As shown in FIGS. 2 and 3, the lighting device A1 includes a main body 40 and a cover unit 41. The main body 40 is formed of a metal material such as aluminum into a flat bottomed cylindrical shape with an open bottom surface. The main body 40 is fixed to a plurality of suspension bolts protruding downward from the ceiling and is installed on the ceiling. 【0025】 The lighting load 21 is disposed at the center of the main body 40 (see FIG. 2). The lighting load 21 has, for example, one or more lighting white LEDs. Also, the lighting circuit B1 and the storage battery 20 are housed above the lighting load 21 in the main body 40 (see FIG. 2). 【0026】 The cover unit 41 has a translucent cover 410 and a frame 411 (see Figure 3). The translucent cover 410 is formed in an approximately hemispherical shape from a translucent, non-combustible material such as glass. However, it is preferable that the translucent cover 410 be painted with a milky white paint or the like. The frame 411 is formed in a cylindrical shape from a metal material such as aluminum. The translucent cover 410 is attached to the frame 411 so as to protrude downward from an opening on the lower side of the frame 411 (see Figure 3). Female threads are formed near the upper end on the inner circumferential surface of the frame 411. 【0027】 The cover unit 41 is detachably attached to the main body 40 by engaging the male threads formed on the outer circumferential surface of the main body 40's peripheral wall with the female threads formed on the inner circumferential surface of the frame 411 (see Figure 3). 【0028】 (2-2) Circuit configuration of the lighting circuit Next, the circuit configuration of the lighting circuit B1 will be described in detail with reference to Figure 1. However, in Figure 1, circuits and circuit elements (such as resistors, capacitors, and various control ICs) that are not directly related to this disclosure but are necessary for the actual circuit configuration are omitted. 【0029】 The lighting circuit B1 includes an AC / DC conversion circuit 10, a charging circuit 11, an adjustment circuit 12, a control circuit 13, a control power supply circuit 14, and a switching circuit 15 (see Figure 1). 【0030】 The AC / DC conversion circuit 10 consists of a full-wave rectifier (diode bridge) that full-wave rectifies the AC voltage and AC current supplied from the normal power supply P1, a smoothing capacitor that smooths the pulsating voltage and pulsating current output from the full-wave rectifier, and a DC conversion circuit. The DC conversion circuit has, for example, an isolated flyback converter. The DC conversion circuit boosts or steps down the DC input voltage (voltage across the smoothing capacitor) and outputs it. 【0031】 The charging circuit 11, for example, constitutes a constant current circuit and charges the storage battery 20 with a charging current that is a constant current obtained by converting the DC current output from the AC / DC conversion circuit 10. 【0032】 The adjustment circuit 12 adjusts the DC power output from the AC / DC conversion circuit 10 and supplies it to the lighting load 21 when normal power (AC power) is supplied from the normal power supply P1. Furthermore, when normal power is not supplied from the normal power supply P1, the adjustment circuit 12 adjusts the DC power output from the battery 20 and supplies it to the lighting load 21. The adjustment circuit 12 includes, for example, a boost converter (boost chopper circuit). The adjustment circuit 12 is configured to adjust the output current by PWM control of the switching elements of the boost converter. 【0033】 The control circuit 13 mainly consists of a microcontroller. The control circuit 13 is configured to perform various controls, including the control of the AC / DC conversion circuit 10, the charging circuit 11, and the adjustment circuit 12, as will be described later, by causing the microcontroller's processor to execute a program stored in the microcontroller's memory. 【0034】 The control power supply circuit 14 generates a control power supply voltage V5 for operating the control circuit 13. The control power supply circuit 14 has, for example, a three-terminal regulator. The three-terminal regulator is configured to step down the input voltage to a voltage lower than the input voltage and output it. The input terminal (input section 140) and output terminal (output section 141) of the three-terminal regulator (control power supply circuit 14) are electrically connected via a protective diode D10. 【0035】 The control power supply circuit 14 generates the control power supply voltage V5 using the DC power output from the AC / DC conversion circuit 10 when normal power is supplied from the normal power supply P1. If normal power is not supplied from the normal power supply P1, the control power supply circuit 14 generates the control power supply voltage V5 using the DC power output from the storage battery 20. The control power supply voltage V5 is supplied not only to the control circuit 13, but also to the AC / DC conversion circuit 10, the charging circuit 11, the adjustment circuit 12, and other components. 【0036】 The switching circuit 15 is configured to switch the path for inputting DC power from the storage battery 20 to the input section 140 of the control power supply circuit 14 (hereinafter referred to as "first path LN1") using the drive voltage output from the control circuit 13 and the output voltage of the AC / DC conversion circuit 10. 【0037】 The switching circuit 15 includes a first switching element Q1 inserted into the first path LN1, and a second switching element Q2 electrically connected to the control terminal of the first switching element Q1. 【0038】 The first switching element Q1 is a PNP bipolar transistor, whose emitter is electrically connected to the positive terminal of the battery 20, and whose collector is electrically connected to the input section 140 of the control power supply circuit 14 via diode D9 (first rectifier element). The cathode of diode D9 is electrically connected in parallel with the cathode of diode D8 to the input section 140 of the control power supply circuit 14. The anode of diode D8 is electrically connected to the high-potential output terminal of the AC / DC conversion circuit 10. In other words, diode D8 (fourth rectifier element) is inserted into the path (hereinafter referred to as "second path LN2") that allows current to flow from the AC / DC conversion section 10 to the control power supply circuit 14 without going through the switching circuit 15. 【0039】 On the other hand, the second switching element Q2 is an NPN bipolar transistor, and its collector is electrically connected to the base of the first switching element Q1 via resistor R51, and its emitter is electrically connected to the negative terminal of the battery 20. The base of the second switching element Q2 is electrically connected to the control circuit 13 via resistor R39, the holding circuit 16, and diode D20 (second rectifier element). The base of the second switching element Q2 is also electrically connected to the high-potential output terminal of the AC / DC conversion circuit 10 via diode D21 (third rectifier element). The cathodes of the two diodes D20 and D21 are electrically connected in parallel to the base of the second switching element Q2. The second switching element Q2 turns on when a drive voltage is applied and turns off when the drive voltage is removed. The first switching element Q1 turns on when the second switching element Q2 turns on and turns off when the second switching element Q2 turns off. 【0040】 The holding circuit 16 is configured by electrically connecting one or more capacitors (three capacitors C63, C64, and C65 in the illustrated example) in parallel. One end of these three capacitors C63, C64, and C65 is electrically connected in parallel to the cathodes of two diodes D20 and D21, and is also electrically connected to the base of the second switching element Q2 via resistor R39. The other ends of these three capacitors C63, C64, and C65 are electrically connected to the negative terminal of the storage battery 20. Furthermore, the other ends of these three capacitors C63, C64, and C65 are electrically connected to the input section 140 of the control power supply circuit 14 via capacitor C23, and are also electrically connected to the output section 141 of the control power supply circuit 14 via capacitor C24. 【0041】 The holding circuit 16 is configured to hold the on-state of the second switching element Q2 by discharging the charges stored in the three capacitors C63, C64, and C65 by the output voltage V2 of the AC-DC conversion circuit 10 through the resistor R39 after the AC-DC conversion circuit 10 stops and the output voltage V2 becomes zero. The time during which the holding circuit 16 can hold the on-state of the second switching element Q2 (hereinafter referred to as "holding time Thd") is determined by the total capacitance value of the three capacitors C63, C64, and C65 and the resistance value of the resistor R39. The holding time Thd is set to be longer than the time from when the supply of DC power of the AC-DC conversion circuit 10 stops until a driving voltage is applied to the base of the second switching element Q2 from the control circuit 13. 【0042】 (2-3) Operation of the lighting circuit Next, the operation of the lighting circuit B1 will be described with reference to FIGS. 1 and 4. In FIG. 4, "V1" indicates the AC voltage supplied from the normal power supply P1. Similarly, "V2" is the output voltage of the AC-DC conversion circuit 10, "V3" is the driving voltage output from the control circuit 13, "V4" is the base-emitter voltage of the second switching element Q2 of the holding circuit, "V5" is the control power supply voltage generated by the control power supply circuit 14, and "V6" is the battery voltage of the storage battery 20. 【0043】 (2-3-1) Operation in normal state First, the operation in the normal state (the period of time t < t1 in FIG. 4) when AC power (AC voltage V1) is supplied from the normal power supply P1 will be described. 【0044】 Under normal conditions, the lighting circuit B1 charges the battery 20 via the charging circuit 11 using a specified output voltage V2 from the AC / DC conversion circuit 10, and the control circuit 13 lights up the lighting load 21 via the adjustment circuit 12. Here, under normal conditions, the output voltage V2 of the AC / DC conversion circuit 10 is applied to the input section 140 of the control power supply circuit 14 via diode D8. Therefore, the control power supply circuit 14 can create a control power supply voltage V5 from the output voltage V2 input to the input section 140. In addition, under normal conditions, the output voltage V2 of the AC / DC conversion circuit 10 is also applied to the base of the second switching element Q2 via diode D21. Therefore, the switching circuit 15 closes the first path LN1. However, since the output voltage V2 of the AC / DC conversion circuit 10 is higher than the battery voltage V6 of the battery 20, the diode D9 inserted in the first path LN1 does not conduct, and therefore the battery 20 does not discharge via the first path LN1. 【0045】 However, under normal conditions, the lighting circuit B1 operates to light the lighting load 21 using the normal power supplied from the normal power supply P1 while simultaneously charging the storage battery 20. 【0046】 (2-3-2) Operation during a power outage Next, we will explain the operation when the supply of AC power (AC voltage V1) from the normal power supply P1 to the lighting circuit B1 is interrupted. Note that the interruption of power supply from the normal power supply P1 to the lighting circuit B1 includes not only cases where the normal power supply P1 fails, but also cases where the power supply path is interrupted by a circuit breaker inserted in the power supply path from the normal power supply P1 to the lighting circuit B1. However, in the following explanation, we will describe the operation when the normal power supply P1 fails. 【0047】 Assume that the normal power supply P1 is interrupted at time t=t1 (see Figure 4). When the normal power supply P1 is interrupted, the AC / DC converter circuit 10 stops operating. However, as the charge in the smoothing capacitor located in the output stage of the AC / DC converter circuit 10 is discharged, the output voltage V2 of the AC / DC converter circuit 10 gradually decreases to zero from the time the power outage occurred (time t=t1) (see Figure 4). 【0048】 On the other hand, the holding circuit 16 discharges the charge from the three capacitors C63, C64, and C65, thereby making the rate at which the base-emitter voltage V4 of the second switching element Q2 of the switching circuit 15 decreases significantly slower than the rate at which the output voltage V2 of the AC / DC conversion circuit 10 decreases (see Figure 4). 【0049】 Here, the control circuit 13 monitors the state of the normal power supply P1 based on the output voltage V2 of the AC / DC conversion circuit 10. When the control circuit 13's microcontroller does not detect a power outage of the normal power supply P1 (normal operation), it operates in a low-power operation mode (normal operation mode) to reduce power consumption. When the control circuit 13's microcontroller detects a power outage of the normal power supply P1, it switches from the normal operation mode to the power outage operation mode. However, the control circuit 13's microcontroller requires a predetermined switching time (the time difference between time t=t2 and time t=t1 in Figure 4) to complete the transition from the normal operation mode to the power outage operation mode. This switching time depends on the processing performance of the microcontroller and is, for example, several tens of milliseconds to several hundred milliseconds. 【0050】 The control circuit 13 outputs a drive voltage V3 (at a high level) after the switching time has elapsed. When the drive voltage V3 is output from the control circuit 13 (time t=t2), the base-emitter voltage V4 of the second switching element Q2 returns to its normal level (see Figure 4). 【0051】 However, the switching circuit 15 can keep the first path LN1 closed even during the switching time when the control circuit 13 switches from the normal operating mode to the operating mode during a power outage. Therefore, the control power supply circuit 14 can continue to generate and output the control power supply voltage V5 using the DC power supplied from the storage battery 20 even during the switching time. Note that if the lighting circuit B1 does not have a holding circuit 16, the generation of the control power supply voltage V5 by the control power supply circuit 14 will stop before the output voltage V2 of the AC / DC conversion circuit 10 becomes zero. As a result, the lighting circuit B1 will not be able to light up the lighting load 21 because the operation of the control circuit 13 stops and the switching circuit 15 opens the first path LN1. 【0052】 However, since the lighting circuit B1 has a holding circuit 16, it can continue to supply the control power voltage V5 generated by the control power supply circuit 14 to the control circuit 13 even during the switching time. As a result, the lighting circuit B1 can continue to light the lighting load 21 even after switching from the normal operating mode to the power outage operating mode. 【0053】 Furthermore, in the operation mode during a power outage, the control circuit 13 monitors the battery voltage V6 of the storage battery 20, and when the battery voltage V6 of the storage battery 20 reaches a predetermined threshold (time t=t3 in Figure 4), it stops the output of the drive voltage V3 and stops the adjustment circuit 12 to turn off the lighting load 21. After the output of the drive voltage V3 is stopped, the base-emitter voltage V4 of the second switching element Q2 gradually decreases due to the holding action of the holding circuit 16. Then, when the base-emitter voltage V4 reaches the lower limit (time t=t4), the second switching element Q2 and the first switching element Q1 turn off and the first path LN1 is opened. As a result, the battery voltage V6 of the storage battery 20 is no longer input to the input section 140 of the control power supply circuit 14, so the control power supply voltage V5 becomes zero, and the control circuit 13 and the adjustment circuit 12 also stop. 【0054】 However, the lighting circuit B1 stops outputting the drive voltage V3 when the battery voltage V6 of the storage battery 20 reaches a predetermined threshold, causing the switching circuit 15 to open the first path LN1. This prevents the storage battery 20 from being over-discharged and helps to suppress the deterioration of the storage battery 20. 【0055】 (2-4) Other advantages of the embodiment In normal operation, the switching circuit 15 closes the first path LN1 when the output voltage V2 of the AC / DC converter circuit 10 turns on the second switching element Q2 and the first switching element Q1. In the event of a power outage, the switching circuit 15 closes the first path LN1 when the drive voltage V3 output from the control circuit 13 turns on the second switching element Q2 and the first switching element Q1. 【0056】 For example, if the switch circuit 15 is operated using the drive voltage V3 output from the control circuit 13 even under normal conditions, the control circuit 13 would need to continuously output the drive voltage V3, which could lead to an increased processing load and power consumption for the control circuit 13 (microcontroller). 【0057】 In contrast, the lighting circuit B1 has a switching circuit 15 configured to open and close the first path LN1 using the drive voltage V3 output from the control circuit 13 and the output voltage V2 of the AC / DC conversion circuit 10 (see Figure 1). Therefore, the lighting circuit B1 does not need to constantly output the drive voltage V3 from the control circuit 13 under normal conditions, thereby reducing the processing load and power consumption of the control circuit 13 (microcontroller). 【0058】 Furthermore, the lighting circuit B1 includes three capacitors C63, C64, and C65 in the holding circuit 16, which are charged by the output voltage V2 of the AC / DC conversion circuit 10. The lighting circuit B1 is configured with a switching circuit 15 so that the first path LN1 can be closed by the charge of capacitors C63, C64, and C65 instead of the drive voltage V3. As a result, the lighting circuit B1 can realize the holding circuit 16 with a simple circuit configuration, thereby suppressing increases in manufacturing costs, etc. 【0059】 Here, the switching circuit 15 includes a first switching element Q1 inserted into the first path LN1, and a second switching element Q2 electrically connected to the control terminal (base) of the first switching element Q1. The second switching element Q2 turns on the first switching element Q1 by the output voltage V2 of the AC / DC conversion circuit 10 or the drive voltage V3 output from the control circuit 13. Since the lighting circuit B1 has the switching circuit 15 configured as described above, the switching circuit 15 can be made smaller compared to when the switching circuit 15 is configured with an electromagnetic relay or the like. 【0060】 Furthermore, the lighting circuit B1 includes a first rectifier element (diode D9) inserted in the first path LN1 leading from the storage battery 20 to the control power supply circuit 14 via the switching circuit 15, a second rectifier element (diode D20) inserted in the circuit that applies the drive voltage V3 from the control circuit 13 to the switching circuit 15, a third rectifier element (diode D21) inserted in the supply path that supplies DC power from the AC / DC conversion circuit 10 to the switching circuit 15, and a fourth rectifier element (diode D8) inserted in the second path LN2 leading from the AC / DC conversion circuit 10 to the control power supply circuit 14 without going through the switching circuit 15 (see Figure 1). By including these rectifier elements (diodes D9, D20, D21, D8), the lighting circuit B1 can prevent current from unintentionally flowing back into the first switching element Q1, the control circuit 13, and the AC / DC conversion circuit 10. 【0061】 (3) Summary A lighting circuit (B1) according to a first aspect of this disclosure comprises an AC / DC converter (10), a charging circuit (11), an adjustment circuit (12), a control circuit (13), a control power supply circuit (14), and a switching circuit (15). The AC / DC converter (10) converts AC power supplied from a normal power supply (P1) into DC power (output voltage V2). The charging circuit (11) charges a storage battery (20) with DC power. The adjustment circuit (12) adjusts the DC power and the DC power output from the storage battery (20) and supplies them to a lighting load (21). The control circuit (13) controls the AC / DC converter (10), the charging circuit (11), and the adjustment circuit (12). The control power supply circuit (14) generates a control power supply voltage (V5) to operate the control circuit (13). The switching circuit (15) opens and closes the path (first path LN1) for inputting DC power from the storage battery (20) to the input section (140) of the control power supply circuit (14). The switching circuit (15) is configured to open and close the path by a drive voltage (V3) output from the control circuit (13). The control circuit (13) outputs a drive voltage (V3) to the switching circuit (15) to close the path when the supply of AC power from the normal power supply (P1) is stopped. The control circuit (13) stops outputting the drive voltage (V3) and opens the path when the battery voltage (V6) of the storage battery (20) reaches a predetermined threshold. 【0062】 In the first embodiment of the lighting circuit (B1), when power is supplied from the storage battery (20) to the control power supply circuit (14), when the battery voltage (V6) of the storage battery (20) reaches a predetermined threshold, the control circuit (13) stops outputting the drive voltage (V3) and opens the path (first path LN1) to the switching circuit (15). As a result, the lighting circuit (B1) in the first embodiment can prevent the storage battery (20) from being over-discharged and suppress the deterioration of the storage battery (20). 【0063】 A lighting circuit (B1) according to a second aspect of this disclosure can be realized by combining it with the first aspect. In the lighting circuit (B1) according to the second aspect, the switching circuit (15) is preferably configured to open and close the path using the drive voltage (V3) and the DC power of the AC / DC conversion circuit (10). 【0064】 The lighting circuit (B1) according to the second embodiment does not require the control circuit (13) to continuously output a drive voltage (V3) when AC power is supplied from the normal power supply (P1), thereby reducing the processing burden on the control circuit (13) and power consumption. 【0065】 A lighting circuit (B1) according to a third aspect of the present disclosure can be realized in combination with the first or second aspect. The lighting circuit (B1) according to the third aspect preferably further comprises a holding circuit (16). The holding circuit (16) is preferably configured to maintain the state in which the switching circuit (15) closes the path after the supply of DC power has stopped and until the drive voltage (V3) is applied. 【0066】 The lighting circuit (B1) according to the third embodiment can continue to supply the control power voltage (V5) generated by the control power circuit (14) to the control circuit (13) even after the supply of DC power from the normal power supply (P1) has stopped and before the drive voltage (V3) is applied. As a result, the lighting circuit (B1) according to the third embodiment can continue to light the lighting load (21) even after the supply of DC power from the normal power supply (P1) has stopped. 【0067】 A lighting circuit (B1) according to a fourth aspect of this disclosure can be realized in combination with a third aspect. In the lighting circuit (B1) according to the fourth aspect, the holding circuit (16) preferably has one or more capacitors (C63, C64, C65) that are charged by the DC power of the AC / DC conversion circuit (10). The switching circuit (15) is preferably configured so that the path can be closed by the charge of the capacitors (C63, C64, C65) instead of the drive voltage (V3). 【0068】 The lighting circuit (B1) according to the fourth embodiment realizes the holding circuit (16) with a simple circuit configuration, thereby suppressing increases in manufacturing costs, etc. 【0069】 A lighting circuit (B1) according to a fifth aspect of this disclosure can be realized in combination with any of the first to fourth aspects. In the lighting circuit (B1) according to the fifth aspect, the switching circuit (15) preferably includes a first switching element (Q1) inserted into the path and a second switching element (Q2) electrically connected to the control terminal of the first switching element (Q1). The second switching element (Q2) preferably turns on the first switching element (Q1) by the DC power or drive voltage (V3) of the AC / DC conversion circuit (10). 【0070】 The lighting circuit (B1) according to the fifth embodiment allows for miniaturization of the switching circuit (15) compared to the case where the switching circuit (15) is configured with an electromagnetic relay or the like. 【0071】 A lighting circuit (B1) according to a sixth aspect of this disclosure can be realized in combination with any of the first to fifth aspects. Preferably, the lighting circuit (B1) according to the sixth aspect further comprises a first rectifier element (diode D9) inserted in a current path (first path LN1) from a storage battery (20) to a control power supply circuit (14) via a switching circuit (15), a second rectifier element (diode D20) inserted in a circuit that applies a drive voltage from a control circuit (13) to the switching circuit (15), a third rectifier element (diode D21) inserted in a supply path that supplies DC power from an AC / DC conversion circuit (10) to the switching circuit (15), and a fourth rectifier element (diode D8) inserted in a current path (second path LN2) from an AC / DC conversion circuit (10) to a control power supply circuit (14) without going through a switching circuit (15). 【0072】 The lighting circuit (B1) according to the sixth embodiment can prevent current from flowing unintentionally back into the first switching element (Q1), the control circuit (13), and the AC / DC conversion circuit (10), etc. 【0073】 A lighting device (A1) according to the seventh aspect of this disclosure comprises a lighting circuit (B1) according to any of the first to sixth aspects, and a lighting load (21) that is lit by DC power supplied from a control circuit (12) of the lighting circuit (B1). 【0074】 The lighting device (A1) according to the seventh embodiment can prevent the storage battery (20) from being over-discharged and suppress the deterioration of the storage battery (20). [Explanation of Symbols] 【0075】 A1 Lighting device B1 Lighting Circuit P1 Regular power supply LN1 First path (current path) LN2 Second path (current path) V2 Output voltage (DC power) of AC / DC converter circuit V3 Drive Voltage V5 Control power supply voltage C63, C64, C65 Capacitors Q1 First switching components Q2 Second switching D8 Diode (4th rectifier element) D9 Diode (First rectifier element) D20 Diode (Second Rectifier Element) D21 Diode (Third Rectifier Element) 10 AC / DC Converter Circuit 11 Charging circuit 12 Adjustment circuit 13 Control circuits 14 Control Power Supply Circuit 15 Switching circuits 16 Holding circuit 20 Storage batteries 21 Lighting load 140 Input section

Claims

[Claim 1] An AC / DC converter circuit that converts AC power supplied from a regular power source into DC power, A charging circuit that charges the storage battery using the aforementioned DC power, An adjustment circuit that adjusts the DC power and the DC power output from the storage battery and supplies them to a lighting load, A control circuit that controls the AC / DC conversion circuit, the charging circuit, and the adjustment circuit, A control power supply circuit that generates a control power supply voltage for operating the control circuit, A switching circuit that opens and closes the path for inputting the DC power from the storage battery to the input of the control power supply circuit, Equipped with, The switching circuit is configured to open and close the path by the drive voltage output from the control circuit, The control circuit outputs the drive voltage to the switching circuit to close the path when the supply of AC power from the normal power supply is stopped, and stops outputting the drive voltage to open the path when the battery voltage of the storage battery reaches a predetermined threshold. Lighting circuit. [Claim 2] The switching circuit is configured to switch the path open and closed by the drive voltage and the DC power of the AC / DC conversion circuit. The lighting circuit according to claim 1. [Claim 3] It also includes a holding circuit, The holding circuit is configured to maintain the state in which the switching circuit closes the path after the supply of DC power is stopped and until the drive voltage is applied. The lighting circuit according to claim 1 or 2. [Claim 4] The holding circuit has one or more capacitors that are charged by the DC power of the AC / DC conversion circuit. The switching circuit is configured to close the path by the charge of the capacitor instead of the drive voltage. The lighting circuit according to claim 3. [Claim 5] The switching circuit includes a first switching element inserted into the path and a second switching element electrically connected to the control terminal of the first switching element. The second switching element turns on the first switching element by the DC power or the drive voltage of the AC / DC conversion circuit. The lighting circuit according to claim 1 or 2. [Claim 6] The system further comprises: a first rectifier element inserted in the current path from the battery to the control power supply circuit via the switchgear; a second rectifier element inserted in the circuit that applies the drive voltage from the control circuit to the switchgear; a third rectifier element inserted in the supply path that supplies DC power from the AC / DC converter to the switchgear; and a fourth rectifier element inserted in the current path from the AC / DC converter to the control power supply circuit without going through the switchgear. The lighting circuit according to claim 1 or 2. [Claim 7] A lighting circuit according to claim 1 or 2, A lighting load that is lit by DC power supplied from the adjustment circuit of the lighting circuit, Having, Lighting device.

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