Lighting devices and emergency lighting fixtures

Abstract

To provide a lighting device and emergency lighting equipment that can suppress a drop in control voltage even immediately after a power outage in a regular power source while suppressing an increase in size.SOLUTION: In a lighting device 1, a power outage detection circuit 13 detects a power outage in a commercial AC power supply P1 when an intermediate voltage Vi, which is a voltage generated by commercial power, becomes less than a threshold value. A control circuit 14 controls a load circuit K to which the intermediate voltage Vi is input. A control power supply circuit 15 generates a control voltage Vc for operating the control circuit 14 from the intermediate voltage Vi. When the power outage detection circuit 13 detects a power outage, the control circuit 14 adjusts a load current Ia flowing through the load circuit K using the intermediate voltage Vi.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a lighting device and an emergency lighting fixture.

Background Art

[0002] The lighting device of Patent Document 1 includes a converter, a constant voltage circuit, a charging circuit, a control power supply circuit, a lighting circuit, and a control circuit. The converter is supplied with an AC input voltage from an external power source such as a commercial power system, and converts the AC input voltage into a DC first intermediate voltage. The constant voltage circuit converts the DC first intermediate voltage output by the converter into a DC second intermediate voltage. The charging circuit is supplied with the second intermediate voltage from the constant voltage circuit and is configured to pass a charging current to the battery. The lighting circuit is configured to light a light source with the discharge power of the battery when the external power source fails.

[0003] The control circuit has a control function for controlling the charging circuit and the lighting circuit, and a power failure detection function for detecting a power failure of the external power source. Then, when the external power source is powered on, the control circuit turns off the light source and charges the battery using the external power supplied from the external power source. Also, when the external power source fails, the control circuit stops charging the battery and lights the light source with the discharge power of the battery.

[0004] The control power supply circuit converts the voltage of the external power source or the voltage of the battery into a DC control voltage. The control power supply circuit generates a control voltage from the voltage of the external power source when the external power source is powered on, and generates a control voltage from the voltage of the battery when the external power source fails. The control voltage is a voltage for operating the control circuit.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In lighting devices like the one described in Patent Document 1 above, if the normal power supply (external power supply), such as commercial power, fails, it becomes impossible to generate the control voltage from the normal power supply. Therefore, in lighting devices, when the normal power supply fails, the control voltage is generated from an emergency power supply such as a battery. However, there is a delay between detecting the power outage and generating the control voltage from the emergency power supply, which could cause the control voltage to drop and potentially stop the operation of the control circuit.

[0007] Therefore, conventional lighting devices needed to be modified by adding a capacitor to store the control voltage or by increasing the capacitance of the capacitor. However, adding a capacitor or increasing the capacitance of the capacitor resulted in the lighting device becoming larger, which presented a challenge.

[0008] The purpose of this disclosure is to provide a lighting device and an emergency lighting fixture that can suppress the decrease in control voltage even immediately after a power outage of the normal power supply, while keeping the size of the device under control. [Means for solving the problem]

[0009] A lighting device according to one aspect of this disclosure comprises a normal lighting circuit, an emergency lighting circuit, a charging circuit, a power failure detection circuit, a control circuit, and a control power supply circuit. The normal lighting circuit lights up a light source with normal power supplied from a normal power supply. The emergency lighting circuit lights up the light source with emergency power supplied from an emergency power supply. The charging circuit lights up the light source with the normal power. The normal power supply is charged. The power failure detection circuit detects a power failure in the normal power supply when the intermediate voltage, which is the voltage generated by the normal power supply, falls below a threshold. The control circuit controls the load circuit to which the intermediate voltage is input. The control power supply circuit generates a control voltage from the intermediate voltage to operate the control circuit. When the emergency lighting circuit is operating, it generates an auxiliary voltage using the emergency power to supply power to the control power supply circuit. When the power outage detection circuit detects the power outage, the control circuit... The intermediate voltage is maintained at or above the steady-state value of the auxiliary voltage until the rise time has elapsed. The load current flowing through the load circuit due to the aforementioned intermediate voltage Reduce .

[0010] An emergency lighting fixture according to one aspect of the present disclosure comprises the above-described lighting device, the light source that is lit by the lighting device, the emergency power supply, and a body that houses the lighting device, the light source, and the emergency power supply. [Effects of the Invention]

[0011] As explained above, this disclosure has the effect of suppressing the decrease in control voltage even immediately after a power outage of the normal power supply, while keeping the size of the device under control. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a block diagram showing a lighting device according to an embodiment of the present disclosure. [Figure 2] Figure 2 is an external perspective view of an emergency lighting fixture equipped with the same lighting device as described above. [Figure 3] Figure 3 is an exploded perspective view of the same emergency lighting fixture. [Figure 4] Figure 4 is a waveform diagram showing the operation of the lighting device described above. [Figure 5] Figure 5 is a block diagram showing a comparative example of a lighting device. [Figure 6] Figure 6 is a waveform diagram showing the operation of the lighting device of the comparative example. [Modes for carrying out the invention]

[0013] The lighting device 1 and emergency lighting fixture A1 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.

[0014] (1) Overview As shown in Figure 1, the lighting device 1 according to this embodiment includes a normal lighting circuit 10, an emergency lighting circuit 11, a charging circuit 12, a power failure detection circuit 13, a control circuit 14, and a control power supply circuit 15. The normal lighting circuit 10 lights up an LED (Light Emitting Diode) 2 (light source) with normal power supplied from a commercial AC power supply P1 (normal power supply). The emergency lighting circuit 11 lights up an LED 2 with emergency power supplied from a battery unit B1 (emergency power supply). The charging circuit 12 charges the battery unit B1 with normal power. The power failure detection circuit 13 detects a power failure of the commercial AC power supply P1 when the intermediate voltage Vi, which is the voltage generated by the normal power, falls below a threshold Vt (see Figure 4). The control circuit 14 controls a load circuit K to which the intermediate voltage Vi is input. The control power supply circuit 15 generates a control voltage Vc from the intermediate voltage Vi to operate the control circuit 14. Then, when the power outage detection circuit 13 detects a power outage, the control circuit 14 adjusts the load current Ia flowing through the load circuit K using the intermediate voltage Vi. In Figure 1, the load circuit K is shown as the output adjustment circuit 16 and the charging circuit 12, but it may also be a sensor or other device not shown, and is not limited to a specific circuit.

[0015] The lighting device 1 described above generates an intermediate voltage Vi from the normal power supply, and the control voltage Vc is generated from the intermediate voltage Vi. The intermediate voltage Vi is input to the load circuit K, and a load current Ia flows through the load circuit K. When the commercial AC power supply P1 fails, the intermediate voltage Vi decreases, and when the intermediate voltage Vi decreases, the control voltage Vc decreases. However, when the commercial AC power supply P1 fails, the lighting device 1 suppresses the decrease in the intermediate voltage Vi by adjusting the load current Ia, so that the decrease in the control voltage Vc can be suppressed even immediately after the commercial AC power supply P1 fails.

[0016] (2) Details of the emergency lighting fixture according to the embodiment The emergency lighting fixture A1 according to the embodiment (hereinafter abbreviated as the emergency lighting fixture A1) will be described in detail with reference to the drawings. The emergency lighting fixture A1 described below is an emergency exit guide light installed at the emergency exit or the passage to the emergency exit of buildings such as offices and stores. However, the emergency lighting fixture according to the embodiment is not limited to the emergency exit guide light, and may be, for example, a staircase passage guide light installed in a staircase room in a building, or an emergency light installed on the ceiling of a room or the like. In the following description, unless otherwise specified, the up-down, front-back, and left-right directions indicated by the arrows in FIG. 2 are defined as the up-down, front-back, and left-right directions of the emergency lighting fixture A1.

[0017] The emergency lighting fixture A1 includes a lighting device 1 according to the embodiment (hereinafter abbreviated as the lighting device 1), a housing A10, a light source unit A11, a display block A12, a battery unit B1, etc. (see FIGS. 2 and 3).

[0018] The housing A10 is formed of a synthetic resin material into a rectangular box shape having an opening on the front surface (see FIG. 3). The housing A10 houses the lighting device 1, the battery unit B1, a terminal block 90, a mounting plate 91, etc.

[0019] The mounting plate 91 is formed in a plate shape of a metal material (see FIG. 3). The mounting plate 91 is screwed to the inner bottom surface of the housing A10. The lighting device 1 and the terminal block 90 are screwed to the mounting plate 91 and housed inside the housing A10. Also, the lighting device 1 and the terminal block 90 are electrically connected. The terminal block 90 is electrically connected to a power supply line drawn from a power supply hole 96 provided on the bottom surface of the housing A10 (see FIG. 3). That is, the lighting device 1 is electrically connected to the commercial AC power supply P1 through the terminal block 90 and the power supply line.

[0020] The battery unit B1 is detachably attached to the mounting plate 91. The battery unit B1 is electrically connected to the lighting device 1 in a state of being attached to the mounting plate 91.

[0021] Display block A12 includes a display panel 92, a light guide plate 93, and a holder 94 (see Figure 3).

[0022] The display panel 92 is formed in the shape of a rectangular flat plate from a translucent synthetic resin material such as acrylic resin or polycarbonate resin. However, the display panel 92 may be formed from a translucent material other than synthetic resin, such as quartz glass. A pictogram 921 for evacuation guidance is displayed on the front surface (display surface 920) of the display panel 92 (see Figure 2).

[0023] The light guide plate 93 is formed in the shape of a rectangular flat plate from a light-transmitting synthetic resin material such as acrylic resin or polycarbonate resin. The light guide plate 93 is positioned behind the display panel 92 such that its front surface faces the rear surface of the display panel 92 (see Figure 3). Light emitted from the light source unit A11 is incident on the upper surface (incident surface 930) of the light guide plate 93. The light incident on the incident surface 930 is guided through the light guide plate 93 and emitted from the front surface of the light guide plate 93. The display panel 92 is then illuminated by the light emitted from the emission surface of the light guide plate 93.

[0024] The holder 94 is formed from a non-transparent synthetic resin material in the shape of a rectangular box (frame) with an open front and top. The holder 94 holds the display panel 92 and the light guide plate 93, with the display panel 92 positioned in front of the light guide plate 93 (see Figure 3).

[0025] The display block A12 is attached to the body A10 so as to cover the remaining portion of the opening of the body A10, excluding the upper part where the light source unit A11 is attached (see Figure 2).

[0026] The light source unit A11 includes an LED2 that serves as a light source (see Figure 1), a light guide that directs the light emitted from the LED2, and a housing 95 that houses the LED2 and the light guide (see Figure 3).

[0027] The housing 95 is formed in the shape of a long box with its bottom and rear open. The LED 2 is mounted on a circuit board and housed in one end (right end) of the housing 95 in the longitudinal direction. The light guide is formed in the shape of a long rectangular prism, with one end face (right end face) in the longitudinal direction facing the LED 2, and its longitudinal side (bottom surface) facing the opening in the bottom of the housing 95, and is housed in the housing 95. A portion of the circuit board on which the LED 2 is mounted (hereinafter referred to as the projection 97) protrudes from the rear surface of the housing 95 (see Figure 3).

[0028] The light source unit A11 is attached to the main body A10 by fitting it into the upper front part of the main body A10. At this time, the projection 97 is inserted into the connector 98 located in the upper right corner of the main body A10, thereby electrically connecting the light source unit A11 (LED2) and the lighting device 1 via the connector 98 and electric wires (not shown).

[0029] However, when the light source unit A11 is attached to the body A10, the incident surface 930 of the light guide plate 93 and the exit port of the light source unit A11 face each other in the vertical direction. Therefore, almost all of the light emitted from the exit port of the light source unit A11 enters the light guide plate 93 from its incident surface 930. The light that enters the light guide plate 93 travels through the light guide plate 93, undergoes total internal reflection at the rear surface of the holder 94, and exits forward from the exit surface of the light guide plate 93 to illuminate the display panel 92.

[0030] (3) Details of the lighting device according to the embodiment Next, the lighting device 1 will be described in detail with reference to the block diagram in Figure 1.

[0031] The lighting device 1 includes a normal lighting circuit 10, an emergency lighting circuit 11, a charging circuit 12, a power failure detection circuit 13, a control circuit 14, a control power supply circuit 15, and an output adjustment circuit 16, etc. The lighting device 1 also further includes a rectifier circuit 40, an input capacitor 41, and diodes D1-D4, etc.

[0032] The lighting device 1 uses the commercial AC power supply P1 as its normal power source and the battery unit B1 as its emergency power source, and uses the normal power supplied from the commercial AC power supply P1 and the emergency power supplied from the battery unit B1 to light up the LED 2. The lighting device 1 also charges the battery unit B1 using the normal power supplied from the commercial AC power supply P1.

[0033] (3.1) Rectifier circuit, input capacitor The rectifier circuit 40 is a diode bridge. The rectifier circuit 40 full-wave rectifies the AC voltage Vac (for example, a sinusoidal voltage with a frequency of 50Hz or 60Hz and an effective value of 100V or 200V) input from the commercial AC power supply P1. The pulsating voltage output from the rectifier circuit 40 is smoothed by an input capacitor 41, which is an electrolytic capacitor. The DC voltage smoothed by the input capacitor 41 is then input to the normal lighting circuit 10.

[0034] (3.2) Regular lighting circuit The normal lighting circuit 10 lights the LED2 using the normal power supplied from the commercial AC power supply P1. In this embodiment, the normal power is supplied from the commercial AC power supply P1 to the normal lighting circuit 10 via the rectifier circuit 40 and the input capacitor 41.

[0035] The normal lighting circuit 10 has a so-called isolated flyback converter, which includes a transformer T1, a switching element Q1, a diode D1, a smoothing capacitor C1, and a converter control unit 10a.

[0036] The first end of the primary winding N1 of transformer T1 is electrically connected to the high-potential terminal of input capacitor 41, and the second end of the primary winding N1 is electrically connected to the drain terminal of switching element Q1. Switching element Q1 is an N-channel field-effect transistor. The source terminal of switching element Q1 is electrically connected to the low-potential terminal of input capacitor 41. The gate terminal of switching element Q1 is electrically connected to the converter control unit 10a.

[0037] The first end of the secondary winding N2 of transformer T1 is electrically connected to the anode of diode D1, and the second end of the secondary winding N2 is electrically connected to the low-potential terminal of smoothing capacitor C1. Furthermore, the high-potential terminal of smoothing capacitor C1 is electrically connected to the cathode of diode D1. Additionally, the high-potential terminal of smoothing capacitor C1 is electrically connected to the anode of LED2 via output adjustment circuit 16. Finally, the low-potential terminal of smoothing capacitor C1 is electrically connected to the cathode of LED2.

[0038] The converter control unit 10a is composed of an integrated circuit. The converter control unit 10a controls the switching element Q1 using PWM (pulse width modulation) to match the lighting current Io, which is the current flowing through the LED2, to a first target value. By matching the lighting current Io to the first target value, the converter control unit 10a lights up the LED2. Note that the converter control unit 10a and the switching element Q1 may be composed of a single integrated circuit.

[0039] In this embodiment, the output adjustment circuit 16 detects the magnitude of the lighting current Io and outputs a feedback signal Y1, including the detection result of the lighting current Io, to the converter control unit 10a. The converter control unit 10a receives the feedback signal Y1 and monitors the magnitude of the lighting current Io, enabling feedback control of the lighting current Io. The lighting device 1 may also include a current detection circuit for detecting the lighting current Io separately from the output adjustment circuit 16. The current detection circuit is preferably configured to include a resistor connected in series with the LED2 through which the lighting current Io flows. Furthermore, it is preferable that the converter control unit 10a receives the feedback signal Y1 via a photocoupler.

[0040] The normal lighting circuit 10 receives the voltage across the input capacitor 41 and, as described above, controls the switching element Q1 with PWM to generate a DC intermediate voltage Vi across the smoothing capacitor C1. In other words, the intermediate voltage Vi is a voltage generated by the normal power.

[0041] (3.3)Charging circuit The charging circuit 12 charges the battery unit B1 using normal power.

[0042] Specifically, the charging circuit 12 is a switching power supply that takes the intermediate voltage Vi of the smoothing capacitor C1 as input and supplies a charging current Ic to the battery unit B1. The charging current Ic is supplied to the battery unit B1 via a diode D2 for preventing reverse current. The charging circuit 12 then charges the battery unit B1 by controlling the charging current Ic while monitoring the battery voltage Vb, which is the voltage of the battery unit B1.

[0043] (3.4) Output adjustment circuit The output adjustment circuit 16 includes a switch element. The switch element of the output adjustment circuit 16 is electrically connected between the high-potential terminal of the smoothing capacitor C1 and the anode of the LED2. In other words, the switch element of the output adjustment circuit 16 is inserted into the power supply path that electrically connects the smoothing capacitor C1 and the LED2, and the output adjustment circuit 16 can selectively switch the power supply path between a conduction state and a disconnection state. Therefore, when the switch element of the output adjustment circuit 16 is ON, the intermediate voltage Vi of the smoothing capacitor C1 supplies a lighting current Io to the LED2, causing the LED2 to light up. On the other hand, when the switch element of the output adjustment circuit 16 is OFF, the lighting current Io supplied from the smoothing capacitor C1 to the LED2 is interrupted, causing the LED2 to turn off. The switch element is preferably a transistor such as a field-effect transistor or a bipolar transistor.

[0044] Furthermore, the output adjustment circuit 16 detects the magnitude of the ignition current Io and outputs a feedback signal Y1, which includes the detection result of the ignition current Io, to the converter control unit 10a.

[0045] (3.5) Power outage detection circuit The power outage detection circuit 13 detects a power outage in the commercial AC power supply P1 when the intermediate voltage Vi, which is the voltage generated by the normal power supply, falls below the threshold Vt (see Figure 4).

[0046] Specifically, the power outage detection circuit 13 is composed of a Zener diode and a resistor, etc. The power outage detection circuit 13 determines that the commercial AC power supply P1 is energized and there is no power outage if the intermediate voltage Vi is greater than or equal to the threshold Vt. The power outage detection circuit 13 determines that the commercial AC power supply P1 is experiencing a power outage if the intermediate voltage Vi is less than the threshold Vt. The power outage detection circuit 13 generates a power outage detection signal Y2 based on the power outage detection result and outputs the power outage detection signal Y2 to the control circuit 14. The control circuit 14 can recognize whether or not the commercial AC power supply P1 is experiencing a power outage based on the power outage detection signal Y2.

[0047] (3.6) Emergency lighting circuit The emergency lighting circuit 11 lights up the LED2 using emergency power supplied from the battery unit B1. In this embodiment, emergency power is supplied from the battery unit B1 to the emergency lighting circuit 11.

[0048] Specifically, the emergency lighting circuit 11 has a flyback converter equipped with a transformer and a switching element, and outputs the battery voltage Vb of the battery unit B1 by boosting or lowering it. The high-potential output terminal of the emergency lighting circuit 11 is electrically connected to the anode of LED2, and the low-potential output terminal of the emergency lighting circuit 11 is electrically connected to the cathode of LED2. The emergency lighting circuit 11 then controls its output to match the lighting current Io, which is the current flowing through LED2, to a second target value. The emergency lighting circuit 11 lights up LED2 by matching the lighting current Io to the second target value. However, the second target value of the emergency lighting circuit 11 is smaller than the first target value of the normal lighting circuit 10.

[0049] Furthermore, when the emergency lighting circuit 11 is operating (boosting or lowering the battery voltage Vb), the emergency lighting circuit 11 generates an auxiliary voltage Vg to supply power to the control power supply circuit 15 using emergency power. A diode D4 for preventing reverse current is electrically connected between the emergency lighting circuit 11 and the control power supply circuit 15, and the auxiliary voltage Vg is input to the control power supply circuit 15 via the diode D4.

[0050] The emergency lighting circuit 11 may also be equipped with a forward converter instead of a flyback converter.

[0051] (3.7) Control power supply circuit The control power supply circuit 15 generates a control voltage Vc to operate the control circuit 14.

[0052] Specifically, the control power supply circuit 15 has a step-down series regulator. A diode D3 for reverse current prevention is electrically connected between the high-potential terminal of the smoothing capacitor C1 and the high-potential input terminal of the control power supply circuit 15, and the intermediate voltage Vi is input to the control power supply circuit 15 via diode D3. In addition, a diode D4 for reverse current prevention is electrically connected between the emergency lighting circuit 11 and the control power supply circuit 15, and the auxiliary voltage Vg generated by the emergency lighting circuit 11 is input to the control power supply circuit 15 via diode D4. That is, the control power supply circuit 15 receives the voltage with the higher value of the intermediate voltage Vi and the auxiliary voltage Vg as the control input voltage Vr via an OR circuit composed of diodes D3 and D4. The control power supply circuit 15 then uses the intermediate voltage Vi or the auxiliary voltage Vg as the control input voltage Vr, generates a control voltage Vc from the control input voltage Vr, and outputs the control voltage Vc to the control circuit 14.

[0053] (3.8) Control circuits The control circuit 14 has a microcontroller. The control circuit 14 operates by receiving a control voltage Vc from the control power supply circuit 15.

[0054] The control circuit 14 receives a power outage detection signal Y2 from the power outage detection circuit 13. Based on the power outage detection signal Y2, the control circuit 14 can determine whether or not the commercial AC power supply P1 is experiencing a power outage. If the commercial AC power supply P1 is not experiencing a power outage, the control circuit 14 operates in normal operating mode. If the commercial AC power supply P1 is experiencing a power outage, the control circuit 14 operates in emergency operating mode.

[0055] In the normal operating mode, the control circuit 14 instructs the converter control unit 10a to operate the normal lighting circuit 10 and switches the output adjustment circuit 16 to a conductive state (switch element ON state). That is, in the normal operating mode, normal power is stored in the smoothing capacitor C1, and the normal power supplies the lighting current Io to the LED2. The control circuit 14 also operates the charging circuit 12 in the normal operating mode. Furthermore, in the normal operating mode, the control circuit 14 does not output the emergency lighting signal Y3 to the emergency lighting circuit 11 (maintaining the emergency lighting signal Y3 at an L level) and keeps the emergency lighting circuit 11 in a stopped state. Thus, in the normal operating mode, the LED2 lights up (normal lighting) due to the normal lighting circuit 10, and the battery unit B1 is charged by the charging circuit 12. Here, the normal lighting circuit 10 operates, generating an intermediate voltage Vi. The control power supply circuit 15 then uses the intermediate voltage Vi as the control input voltage Vr to generate a control voltage Vc, and the control circuit 14 becomes operational.

[0056] In emergency operation mode, the control circuit 14 outputs an emergency lighting signal Y3 to the emergency lighting circuit 11 (maintaining the emergency lighting signal Y3 at a high level). The emergency lighting circuit 11 operates if the emergency lighting signal Y3 is at a high level. When the emergency lighting circuit 11 operates, emergency power from the battery unit B1 is supplied to the control power supply circuit 15 through the emergency lighting circuit 11, and the control power supply circuit 15 generates a control voltage Vc from the auxiliary voltage Vg, allowing the control circuit 14 to operate. In other words, when the power outage detection circuit 13 detects a power outage, the control power supply circuit 15 generates a control voltage Vc from the emergency power. Also, when the emergency lighting circuit 11 operates, emergency power from the battery unit B1 is supplied to LED2 through the emergency lighting circuit 11, and LED2 lights up. Thus, LED2 lights up (emergency lighting) due to the emergency lighting circuit 11.

[0057] The following details the operation during mode switching, specifically when switching from the normal operating mode to the emergency operating mode.

[0058] (3.9) Operation when switching modes (3.9.1) Comparative Example Figure 5 shows the block configuration of the comparative example lighting device 100. Lighting device 100 differs from lighting device 1 in that it has a control circuit 140 instead of the control circuit 14 of lighting device 1. The control circuit 140 is supplied with a control voltage Vc generated by the control power supply circuit 15 and operates according to the control voltage Vc. For lighting device 100, the same reference numerals are used for components similar to lighting device 1 of this embodiment shown in Figure 1, and their descriptions are omitted.

[0059] Figure 6 shows the voltage and signal waveforms of each part of the lighting device 100 before and after a commercial AC power supply P1 failure. From top to bottom, Figure 6 shows the waveforms of the AC voltage Vac, intermediate voltage Vi, power failure detection signal Y2, emergency lighting signal Y3, emergency voltage Ve, auxiliary voltage Vg, and control input voltage Vr.

[0060] First, in Figure 6, the commercial AC power supply P1 is energized until time t10, and an AC voltage Vac is generated. Therefore, the normal lighting circuit 10 operates in the normal operating mode, and the intermediate voltage Vi generated across the smoothing capacitor C1 is a voltage value V10 (>0).

[0061] When the commercial AC power supply P1 is interrupted at time t10, the AC voltage Vac becomes 0 (zero), and the supply of charge to the smoothing capacitor C1 stops. However, the switch element of the output adjustment circuit 16 is on, and the charging circuit 12 continues to operate. Therefore, immediately after time t10, the lighting current Io continues to be supplied from the smoothing capacitor C1 to the LED2, and the battery unit B1 continues to be charged by the intermediate voltage Vi of the smoothing capacitor C1, so the intermediate voltage Vi decreases rapidly. The larger the lighting current Io, the larger the charging current of the battery unit B1, or the smaller the capacitance of the smoothing capacitor C1, the steeper the slope at which the intermediate voltage Vi decreases.

[0062] Then, when the intermediate voltage Vi falls below the threshold Vt at time t11, the power outage detection circuit 13 detects a power outage in the commercial AC power supply P1 and transitions the power outage detection signal Y2 from L level to H level. When the control circuit 140 receives the H level power outage detection signal Y2, it operates in emergency mode and transitions the emergency lighting signal Y3 from L level to H level. When the emergency lighting circuit 11 receives the H level emergency lighting signal Y3, it starts operating.

[0063] However, even after the emergency lighting circuit 11 receives the H-level emergency lighting signal Y3 and starts operating, it cannot immediately output the emergency voltage Ve and auxiliary voltage Vg. The emergency voltage Ve and auxiliary voltage Vg output by the emergency lighting circuit 11 gradually increase, reaching their steady-state values ​​Ve1 and Vg1, respectively, after a rise time tr has elapsed since the emergency lighting signal Y3 transitioned to the H level (time t13 in Figure 6). This rise time tr is determined by the configuration of the circuits included in the lighting device 100, the software executed by the control circuit 140, and the rise and fall times of each signal. The rise time tr does not depend on the lighting current Io, the charging current of the battery unit B1, or the capacitance of the smoothing capacitor C1.

[0064] As shown in Figure 6, if the slope of decrease in the intermediate voltage Vi immediately after time t10 is steep, a state will occur where both the intermediate voltage Vi and the auxiliary voltage Vg fall below the steady-state value Vg1 before the auxiliary voltage Vg reaches the steady-state value Vg1. If we define this state, where both the intermediate voltage Vi and the auxiliary voltage Vg fall below the steady-state value Vg1, as a "dip state," then in the dip state, the control input voltage Vr falls below the steady-state value Vg1. As a result, in the dip state, the control voltage Vc output by the control power supply circuit 15 falls below the rated voltage value, which can cause the control circuit 140 to stop operating or malfunction. Note that in Figure 6, before time t12, the intermediate voltage Vi is greater than the auxiliary voltage Vg, and after time t12, the auxiliary voltage Vg is greater than the intermediate voltage Vi.

[0065] Therefore, in the comparative example, the occurrence of dip states was suppressed by increasing the capacitance of the smoothing capacitor C1 or by adding a new capacitor to maintain the control input voltage Vr. However, increasing the capacitance of the smoothing capacitor C1 or adding a new capacitor resulted in an increase in the size and cost of the lighting device 100.

[0066] (3.9.2) Embodiment Therefore, the lighting device 1 of this embodiment operates as follows.

[0067] Figure 4 shows the voltage and signal waveforms of each part of the lighting device 1 before and after a power outage of the commercial AC power supply P1. From top to bottom, Figure 4 shows the waveforms of the AC voltage Vac, intermediate voltage Vi, power outage detection signal Y2, emergency lighting signal Y3, output suppression signal Ya and charge suppression signal Yb, emergency voltage Ve, auxiliary voltage Vg, and control input voltage Vr.

[0068] First, in Figure 4, the commercial AC power supply P1 is energized until time t1, and an AC voltage Vac is generated. Therefore, the normal lighting circuit 10 operates in the normal operating mode, and the intermediate voltage Vi generated across the smoothing capacitor C1 is a voltage value V10 (>0).

[0069] When the commercial AC power supply P1 is interrupted at time t1, the AC voltage Vac becomes 0 (zero), and the supply of charge to the smoothing capacitor C1 stops. However, the switch element of the output adjustment circuit 16 is on, and the charging circuit 12 continues to operate. Therefore, immediately after time t1, the intermediate voltage Vi of the smoothing capacitor C1 continues to supply the lighting current Io to the LED2, and the battery unit B1 continues to be charged by the intermediate voltage Vi, so the intermediate voltage Vi gradually decreases.

[0070] Then, when the intermediate voltage Vi falls below the threshold Vt at time t2, the power outage detection circuit 13 detects a power outage in the commercial AC power supply P1 and transitions the power outage detection signal Y2 from L level to H level. When the control circuit 14 receives the H level power outage detection signal Y2, it operates in emergency mode and transitions the emergency lighting signal Y3 from L level to H level. When the emergency lighting circuit 11 receives the H level emergency lighting signal Y3 and starts operating, the emergency voltage Ve and auxiliary voltage Vg output by the emergency lighting circuit 11 gradually increase and reach steady-state values ​​Ve1 and Vg1, respectively, after the rise time tr has elapsed since the start of operation (time t4 in Figure 4).

[0071] Then, the control circuit 14, operating in emergency mode, transitions the emergency lighting signal Y3 from L level to H level and adjusts the load current Ia flowing through the load circuit K using the intermediate voltage Vi. At this time, it is preferable that the control circuit 14 adjusts the load current Ia flowing through the load circuit K from the smoothing capacitor C1 so that the intermediate voltage Vi remains at or above the steady-state value Vg1 of the auxiliary voltage Vg until the rise time tr has elapsed.

[0072] Specifically, in this embodiment, the load circuit K is comprised of an output adjustment circuit 16 and a charging circuit 12. When distinguishing between the output adjustment circuit 16 and the charging circuit 12, which constitute the load circuit K, the output adjustment circuit 16 is referred to as load circuit K1, and the charging circuit 12 is referred to as load circuit K2. Furthermore, the load current Ia flowing from the smoothing capacitor C1 to the output adjustment circuit 16 (load circuit K1) is referred to as Ia1, and the load current Ia flowing from the smoothing capacitor C1 to the charging circuit 12 (load circuit K2) is referred to as Ia2.

[0073] The control circuit 14 then outputs an output suppression signal Ya to the output adjustment circuit 16 (load circuit K1). The output adjustment circuit 16 (load circuit K1) turns its switch element on or off based on the output suppression signal Ya. The control circuit 14 also outputs a charge suppression signal Yb to the charge circuit 12 (load circuit K2). The charge circuit 12 (load circuit K2) operates or stops based on the charge suppression signal Yb.

[0074] When the control circuit 14 is operating in its normal operating mode, the output suppression signal Ya is at an L level. Therefore, the output adjustment circuit 16 (load circuit K1) has its switch element turned on, and a load current Ia1 flows from the smoothing capacitor C1 to the output adjustment circuit 16 (load circuit K1). In other words, the load current Ia1 is supplied to the LED2 as the lighting current Io.

[0075] Then, when the commercial AC power supply P1 fails (time t1) and the failure detection signal Y2 reaches the H level (time t2), the control circuit 14 operates in emergency mode and transitions the output suppression signal Ya from the L level to the H level (time t3). When the output suppression signal Ya reaches the H level, the output adjustment circuit 16 (load circuit K1) turns off its switching element and cuts off the load current Ia1. By cutting off the load current Ia1, the output adjustment circuit 16 reduces the load current Ia after time t3 to less than the load current Ia before time t3. As a result, the discharge amount of the smoothing capacitor C1 after time t3 is less than the discharge amount of the smoothing capacitor C1 before time t3, and the slope of decrease of the intermediate voltage Vi after time t3 is smaller than the slope of decrease of the intermediate voltage Vi before time t3.

[0076] Furthermore, when the control circuit 14 is operating in its normal operating mode, the charge suppression signal Yb is at an L level. Therefore, the charging circuit 12 (load circuit K2) operates, and a load current Ia2 flows from the smoothing capacitor C1 to the charging circuit 12 (load circuit K2). In other words, the charging circuit 12 (load circuit K2) supplies a charging current Ic to the battery unit B1 using an intermediate voltage Vi.

[0077] Then, when the commercial AC power supply P1 fails (time t1) and the failure detection signal Y2 reaches the H level (time t2), the control circuit 14 operates in emergency mode and transitions the charge suppression signal Yb from the L level to the H level (time t3). When the charge suppression signal Yb reaches the H level, the charging circuit 12 (load circuit K2) stops operating, setting the charging current Ic to zero and the load current Ia2 to zero. As a result of the load current Ia2 becoming zero after time t3, the discharge amount of the smoothing capacitor C1 after time t3 is reduced compared to the discharge amount of the smoothing capacitor C1 before time t3, and the slope of decrease of the intermediate voltage Vi after time t3 is smaller than the slope of decrease of the intermediate voltage Vi before time t3.

[0078] As described above, the control circuit 14 operating in emergency mode reduces the load current Ia (Ia1, Ia2) flowing through the load circuit K (K1, K2) by the intermediate voltage Vi compared to when operating in normal mode. In other words, the control circuit 14 operating in emergency mode reduces the amount of discharge of the smoothing capacitor C1, thereby reducing the amount of decrease in the intermediate voltage Vi during the rise time tr. Therefore, the intermediate voltage Vi can be maintained at or above the steady value Vg1 of the auxiliary voltage Vg until the rise time tr has elapsed.

[0079] However, the lighting device 1 can prevent the control input voltage Vr from falling below the steady-state value Vg1 until the rise time tr has elapsed, without increasing the capacitance of the smoothing capacitor C1 or adding any new capacitors. As a result, the control voltage Vc output by the control power supply circuit 15 is less likely to fall below the rated voltage value, and the operation of the control circuit 14 is prevented from stopping or malfunctioning. Therefore, the lighting device 1 can suppress the decrease in the control voltage Vc even immediately after a power outage of the commercial AC power supply P1, while keeping the size of the device down.

[0080] Furthermore, it is preferable that the control circuit 14 adjusts the load current Ia after a delay time Td (see Figure 4) has elapsed since the power outage detection circuit 13 detected a power outage. Specifically, as shown in Figure 4, when the power outage detection circuit 13 detects a power outage in the commercial AC power supply P1 at time t2 and transitions the power outage detection signal Y2 from L level to H level, the control circuit 14 transitions the output suppression signal Ya and the charge suppression signal Yb from L level to H level at time t3, after the delay time Td has elapsed since the power outage detection signal Y2 transitioned to H level. As a result, even if the intermediate voltage Vi rises due to a reduction or elimination of the load current Ia (Ia1, Ia2) flowing through the load circuit K (K1, K2), it is possible to suppress false detections in which the power outage detection circuit 13 mistakenly detects that the system has returned to a normal state from a power outage state.

[0081] Furthermore, "reducing the load current Ia" includes both making the magnitude of the load current Ia smaller and making the magnitude of the load current Ia zero.

[0082] (4) Variations In the above embodiment, the normal lighting circuit 10 and the emergency lighting circuit 11 illuminate the same LED2. However, the normal lighting circuit 10 and the emergency lighting circuit 11 may illuminate different light sources. That is, the lighting device may include a normal LED that is illuminated when the commercial AC power supply P1 is powered on, and an emergency LED that is illuminated when the commercial AC power supply P1 is powered off.

[0083] The load circuit K may consist of only one of the output adjustment circuit 16 (load circuit K1) and the charging circuit 12 (load circuit K2). Alternatively, the load circuit K may be a sensor that operates at the intermediate voltage Vi of the smoothing capacitor C1.

[0084] Emergency lighting fixture A1 is not limited to disaster prevention lighting fixtures. Emergency lighting fixture A1 can be any lighting fixture that receives emergency power from battery unit B1 to illuminate its light source. Emergency lighting fixture A1 may also be, for example, a lighting fixture that emits illumination light to adjust the illuminance of a space.

[0085] The control circuit 14 preferably comprises a computer system. The computer system mainly consists of a processor and memory as hardware. At least a part of the functions of the control circuit 14 in this disclosure is realized by the processor executing a program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system, provided via a telecommunications line, or provided on a non-temporary recording medium such as a memory card, optical disk, or hard disk drive that can be read by the computer system. The processor of the computer system consists of one or more electronic circuits including semiconductor integrated circuits (ICs) or large-scale integrated circuits (LSIs). The integrated circuits such as ICs and LSIs referred to here are named differently depending on the degree of integration, and include integrated circuits called system LSIs, VLSIs (Very Large Scale Integration), or ULSIs (Ultra Large Scale Integration). Furthermore, FPGAs (Field-Programmable Gate Arrays) that are programmed after the manufacture of the LSI, or logic devices that allow for the reconfiguration of junction relationships or circuit compartments within the LSI, can also be used as processors. Multiple electronic circuits may be integrated onto a single chip or distributed across multiple chips. Multiple chips may be integrated onto a single device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller also consists of one or more electronic circuits, including semiconductor integrated circuits or large-scale integrated circuits.

[0086] The light source is not limited to LEDs; it may also be other solid-state light-emitting elements such as OLEDs (Organic Light Emitting Diodes).

[0087] The lighting device 1 may further include a small-capacity capacitor that holds the control input voltage Vr.

[0088] (5) Summary As described above, the lighting device (1) of the first embodiment comprises a normal lighting circuit (10), an emergency lighting circuit (11), a charging circuit (12), a power failure detection circuit (13), a control circuit (14), and a control power supply circuit (15). The normal lighting circuit (10) lights up the light source (2) with normal power supplied from the normal power supply (P1). The emergency lighting circuit (11) lights up the light source (2) with emergency power supplied from the emergency power supply (B1). The charging circuit (12) charges the emergency power supply (B1) with normal power. The power failure detection circuit (13) detects a power failure of the normal power supply (P1) when the intermediate voltage (Vi), which is a voltage generated by the normal power, falls below a threshold (Vt). The control circuit (14) controls the load circuit (K) to which the intermediate voltage (Vi) is input. The control power supply circuit (15) generates a control voltage (Vc) from the intermediate voltage (Vi) to operate the control circuit (14). When the power failure detection circuit (13) detects a power failure, the control circuit (14) adjusts the load current (Ia) flowing through the load circuit (K) using the intermediate voltage (Vi).

[0089] The aforementioned lighting device (1) can suppress the decrease in control voltage (Vc) even immediately after a power outage of the normal power supply (P1) while keeping the size of the device to a minimum.

[0090] In the lighting device (1) of the second embodiment, in the first embodiment, it is preferable that the control circuit (14) reduces the load current (Ia) when the power outage detection circuit (13) detects a power outage.

[0091] The aforementioned lighting device (1) can suppress the decrease in the control voltage (Vc).

[0092] In the lighting device (1) of the third embodiment, in the first embodiment, it is preferable that the control circuit (14) cuts off the load current (Ia) when the power outage detection circuit (13) detects a power outage.

[0093] The aforementioned lighting device (1) can further suppress the decrease in the control voltage (Vc).

[0094] In the lighting device (1) of the fourth embodiment, in any one of the first to third embodiments, it is preferable that the control circuit (14) adjusts the load current (Ia) after a delay time (Td) has elapsed since the power outage detection circuit (13) detected a power outage.

[0095] The aforementioned lighting device (1) can suppress false detection by the power outage detection circuit (13) even if the intermediate voltage (Vi) rises due to a reduction or elimination of the load current (Ia) flowing through the load circuit (K).

[0096] In the fifth embodiment of the lighting device (1), it is preferable that the device further comprises a capacitor (C1) to which an intermediate voltage (Vi) is applied, in any one of the first to fourth embodiments.

[0097] The aforementioned lighting device (1) can suppress the drop in the control voltage (Vc) even immediately after a power outage of the normal power supply (P1) while keeping the capacitance of the capacitor (C1) low.

[0098] In the sixth embodiment of the lighting device (1), it is preferable that in any one of the first to fifth embodiments, an output adjustment circuit (16) further comprises an output adjustment circuit (16) that supplies a current based on normal power to a light source (2) in an adjustable manner. The load circuit (K1) is the output adjustment circuit (16).

[0099] The aforementioned lighting device (1) uses an output adjustment circuit (16) as the load circuit (K1), thereby suppressing the drop in the control voltage (Vc) even immediately after a power outage of the normal power supply (P1).

[0100] In the lighting device (1) of the seventh embodiment, in the sixth embodiment, the load circuit (K) is preferably an output adjustment circuit (16) and a charging circuit (12).

[0101] The aforementioned lighting device (1) uses an output adjustment circuit (16) and a charging circuit (12) as the load circuit (K), thereby further suppressing the drop in the control voltage (Vc) even immediately after a power outage of the normal power supply (P1).

[0102] In the eighth embodiment of the lighting device (1), in any one of the first to fifth embodiments, the load circuit (K2) is preferably a charging circuit (12).

[0103] The aforementioned lighting device (1) uses a charging circuit (12) as the load circuit (K2), thereby suppressing the drop in the control voltage (Vc) even immediately after a power outage of the normal power supply (P1).

[0104] In the lighting device (1) of the ninth embodiment, in any one of the first to eighth embodiments, it is preferable that the control power supply circuit (15) generates a control voltage (Vc) from emergency power when the power outage detection circuit (13) detects a power outage.

[0105] The aforementioned lighting device (1) can operate even if the normal power supply (P1) fails.

[0106] An emergency lighting fixture (A1) according to the tenth embodiment comprises a lighting device (1) according to any one of the first to ninth embodiments, a light source (2) that is lit by the lighting device (1), an emergency power supply (B1), and a body (A10) that houses the lighting device (1), the light source (2), and the emergency power supply (B1).

[0107] The aforementioned emergency lighting fixture (A1) can suppress the decrease in control voltage (Vc) even immediately after a power outage of the normal power supply (P1) while keeping its size down. [Explanation of Symbols]

[0108] 1. Lighting device 10 Regular lighting circuit 11 Emergency lighting circuit 12 Charging circuit 13. Power outage detection circuit 14 Control circuits 15 Control Power Supply Circuit 16 Output adjustment circuit 2 LED (light source) A1 Emergency lighting fixtures A10 body K(K1, K2) Load circuit C1 Smoothing capacitor (capacitor) P1 Commercial AC power supply (normal power supply) B1 Battery Unit (Emergency Power Supply) Vi Intermediate voltage Vt threshold Vc control voltage Ia(Ia1, Ia2) Load current Td delay time

Claims

1. A normal lighting circuit that lights up the light source using normal power supplied from the normal power source, An emergency lighting circuit that lights the light source with emergency power supplied from an emergency power source, A charging circuit that charges the emergency power supply with the aforementioned normal power, A power outage detection circuit that detects a power outage of the normal power supply when the intermediate voltage, which is the voltage generated by the normal power supply, falls below a threshold, A control circuit that controls the load circuit to which the aforementioned intermediate voltage is input, The system includes a control power supply circuit that generates a control voltage for operating the control circuit from the intermediate voltage, The emergency lighting circuit generates an auxiliary voltage using the emergency power to supply power to the control power supply circuit when the emergency lighting circuit is operating. When the power outage detection circuit detects a power outage, the control circuit reduces the load current flowing through the load circuit by the intermediate voltage so that the intermediate voltage remains above the steady value of the auxiliary voltage until the rise time has elapsed. Lighting device.

2. The control circuit interrupts the load current when the power outage detection circuit detects the power outage. The lighting device according to claim 1.

3. The control circuit reduces the load current after a delay time has elapsed since the power outage detection circuit detected the power outage. The lighting device according to claim 1 or 2.

4. Further comprising a capacitor to which the intermediate voltage is applied The lighting device according to claim 1 or 2.

5. Further comprising an output adjustment circuit that supplies the current by the normal power to the light source in an adjustable manner, The load circuit is the output adjustment circuit. The lighting device according to claim 1 or 2.

6. The load circuit is the output adjustment circuit and the charging circuit. The lighting device according to claim 5.

7. The load circuit is the charging circuit. The lighting device according to claim 1 or 2.

8. The control power supply circuit generates the control voltage from the emergency power when the power outage detection circuit detects the power outage. The lighting device according to claim 1 or 2.

9. A lighting device according to claim 1 or 2, The light source is lit by the aforementioned lighting device, The aforementioned emergency power supply, A casing housing the aforementioned lighting device, the aforementioned light source, and the aforementioned emergency power supply, Equipped with Emergency lighting equipment.

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