Lighting device

Abstract

To provide a lighting device, and provide a lighting fixture that adjusts brightness and turns on a light source depending on whether the input is an AC voltage or a DC voltage.SOLUTION: A lighting device receives input of both AC and DC voltages and lights up a light source. The lighting device executes a process of receiving a voltage from a power source and a process of determining whether the received voltage is an AC voltage or a DC voltage. When the received voltage is an AC voltage, the lighting device is configured to execute a process of lighting the light source so as to realize a first brightness, and when the received voltage is a DC voltage, the lighting device is configured to execute a process of lighting the light source so as to realize a second brightness that is darker than the first brightness.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to a lighting device.

Background Art

[0002] In lighting devices, a technique of supplying power to a load such as an LED using a switching circuit composed of a coil and a switching element is known. The voltage input to the lighting device is mainly an alternating voltage, and voltage-free lighting devices that can handle multiple voltage levels of input are the mainstream. In a lighting device that receives an alternating voltage input, the input alternating voltage is rectified by a rectifier, and the rectified voltage is boosted to convert it to a direct current. Further, the direct current voltage is stepped down so that a predetermined voltage level is obtained, and the stepped-down direct current voltage is used to supply power to a load such as an LED.

[0003] On the other hand, in recent years, the voltage input to lighting devices is not limited to alternating voltage, and for example, lighting devices that are lit by inputting a direct current voltage, such as solar power generation, batteries, or direct current power supply equipment, have been increasing.

[0004] Patent Document 1 discloses a lighting device that can be used for both alternating current and direct current. Large factories or buildings have batteries as emergency power sources, so by making it compatible with both alternating current and direct current, it is possible to provide a lighting device that can be used not only in normal states but also in emergency states. Further, a lighting device that can be used for both alternating current and direct current does not need to incorporate a battery like a conventional emergency light, so it is also excellent from the viewpoints of cost and maintenance.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, conventional lighting devices could accept both AC and DC voltage inputs, but they would light up at the same brightness regardless of whether the input was AC or DC. As a result, the lighting devices would light up at the same brightness in emergency situations as in normal situations, leading to rapid battery drain.

[0007] This disclosure aims to provide a lighting fixture that adjusts the brightness and turns on the light source depending on whether the input is an AC voltage or a DC voltage, in order to solve the above-mentioned problems. [Means for solving the problem]

[0008] A part of this disclosure is a lighting device that accepts both AC and DC voltage inputs and lights a light source, A reception process that receives voltage from the power supply, The aforementioned The input voltage determination process determines whether the received voltage is an AC voltage or a DC voltage during the reception process, If the received voltage is an AC voltage, the light source is turned on to achieve the first brightness. 、 If the received voltage is a DC voltage, 、 A process of referring to the installation height of the aforementioned lighting device, Darker than the first brightness mentioned above. The setting is such that the brightness increases as the installation height increases. A process of turning on the light source so that a second brightness is achieved, It is preferable to configure it to perform the following: [Effects of the Invention]

[0009] According to aspects of this disclosure, it is possible to provide a lighting fixture that adjusts brightness and controls the illumination of a light source depending on whether the input is an AC voltage or a DC voltage. [Brief explanation of the drawing]

[0010] [Figure 1]It is a circuit block diagram of a lighting device according to Embodiment 1 of the present disclosure. [Figure 2] It is a flowchart showing the processing executed by the lighting device according to Embodiment 1 of the present disclosure. [Figure 3] It is a flowchart showing the processing executed by the lighting device according to Embodiment 2 of the present disclosure. [Figure 4] It is a circuit block diagram of a lighting device according to Embodiment 3 of the present disclosure. [Figure 5] It is a flowchart showing the processing executed by the lighting device according to Embodiment 3 of the present disclosure. [Figure 6] It is a circuit block diagram of a lighting device according to Embodiment 4 of the present disclosure. [Figure 7] It is a flowchart showing the processing executed by the lighting device according to Embodiment 4 of the present disclosure.

Embodiments for Carrying Out the Invention

[0011] The lighting device according to the present disclosure will be described with reference to the drawings. The same or corresponding components may be denoted by the same reference numerals, and the repeated description may be omitted.

[0012] Embodiment 1 FIG. 1 is a circuit block diagram of a lighting device according to Embodiment 1 of the present disclosure. The lighting device 100 includes an input unit 10 that receives an alternating voltage AC or a direct voltage DC, a rectifier 20, an input detection circuit 30, a conversion circuit 40, and an LED light source unit 50.

[0013] The input unit 10 includes input terminals. The input unit 10 executes a process of receiving both an alternating voltage AC and a direct voltage DC from a power source via the input terminals (hereinafter referred to as a reception process). Note that the power source that supplies the alternating voltage AC is, for example, a commercial power source.

[0014] When an alternating voltage AC is input to the input section 10, the rectifier 20 full-wave rectifies the alternating voltage AC to generate a pulsating direct voltage. The rectifier 20 is, for example, a diode bridge circuit. A capacitor C1 is connected to the output terminal of the rectifier 20. The capacitor C1 can smooth the voltage full-wave rectified by the rectifier 20. On the other hand, when a direct voltage DC is input to the input section 10, the direct voltage is applied to the rectifier 20 and output to the capacitor C1 as it is.

[0015] The voltage across both ends of the capacitor C1 serves as the operating power supply for a boost chopper circuit 41 described later provided in the conversion circuit 40. When an alternating voltage AC is input to the input section 10, a full-wave rectified voltage (hereinafter referred to as an AC-derived voltage) derived from the alternating voltage AC is applied to the capacitor C1. When a direct voltage DC is input to the input section 10, a voltage proportional to the direct voltage DC (hereinafter referred to as a DC-derived voltage) is applied to the capacitor C1.

[0016] The input detection circuit 30 includes the capacitor C1 and a series circuit composed of a resistor R1 and a resistor R2 connected in parallel to the capacitor C1. In the input detection circuit 30, the midpoint of the circuit resistively divided by the resistors R1 and R2 is connected to the P3 terminal of the control IC 42. Thereby, the control IC 42 can execute a process (hereinafter referred to as an input voltage determination process) for determining whether the input to the input section 10 is an alternating voltage AC or a direct voltage DC.

[0017] The input voltage determination process can be realized by detecting the time change of the voltage input to the P3 terminal. That is, when there is a time change in the voltage, an AC-derived voltage is detected, so it can be determined that an alternating voltage AC is input to the input section 10. On the other hand, when there is no time change in the voltage, a DC-derived voltage is detected, so it can be determined that a direct voltage DC is input to the input section 10. The detection time interval can be freely set, but the detection accuracy can be improved by setting it more finely.

[0018] The conversion circuit 40 converts an AC-derived voltage or a DC-derived voltage into a DC voltage suitable for driving the LED light source unit 50. The conversion circuit 40 comprises a boost chopper circuit 41, a control IC 42, a control power supply circuit unit 43, a step-down circuit unit 44, a MOSFET driver 45, and a buck converter circuit 46.

[0019] The boost chopper circuit 41 includes a coil L1, a switching element MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) Q1, and a diode D1.

[0020] A resistor R6 is connected to the source terminal of MOSFETQ1, an inductor L1 to the drain terminal, and a MOSFET driver 45 to the gate terminal. MOSFETQ1 responds to control by the MOSFET driver 45 and switches the voltage within the boost chopper circuit 41.

[0021] The boost chopper circuit 41 boosts the AC-derived voltage or DC-derived voltage to a DC voltage suitable for the buck converter circuit 46 and charges the capacitor C2.

[0022] When an AC voltage is input to the input section 10, the boost chopper circuit 41 operates as a power factor correction circuit to improve the power factor of the AC voltage. In this circuit, switching control is performed so that the duration of the signal that turns on MOSFET Q1 is constant with respect to the period of the AC voltage. That is, the switching current is controlled to match the phase of the AC voltage.

[0023] On the other hand, when a DC voltage is input to the input section 10, the boost chopper circuit 41 boosts the voltage of capacitor C2 until it reaches a DC voltage suitable for the buck converter circuit 46. In the case of a DC voltage, the voltage is constant regardless of time, so power factor correction circuit operation is unnecessary.

[0024] Resistors R5 and R6 are placed across capacitor C2 and divide the DC voltage charged across capacitor C2. The divided voltage is detected by the P1 terminal of control IC42. This allows control IC42 to control MOSFET Q1 so that the DC voltage charged across capacitor C2 remains constant. Hereafter, the DC voltage charged across capacitor C2 will be referred to as V1.

[0025] The buck converter circuit 46 comprises a MOSFET Q2, an inductor L2, and a diode D2. The buck converter circuit 46 performs switching control on the DC voltage V1 charged in the capacitor C2 to generate a high-frequency voltage. Capacitor C3 is connected in parallel with the buck converter circuit 46 and generates a DC voltage by smoothing the high-frequency voltage output by the buck converter circuit 46. By supplying the DC voltage generated by the buck converter circuit 46 and capacitor C3 to the LED light source unit 50, the LED light source unit 50 can be lit.

[0026] The buck converter current (also called switching current) output by the buck converter circuit 46 flows through resistor R4. The buck converter current is converted into a voltage in resistor R4 and input to the P2 terminal of control IC 42. This allows control IC 42 to control MOSFET Q2 so that the voltage across resistor R4 remains constant. In other words, constant current control can be performed so that the buck converter current remains constant. Since the average value of the buck converter current is equal to the current flowing through the LED light source unit 50 (also called LED current), this means that the current flowing through the LED light source unit 50 is also controlled to be constant.

[0027] Furthermore, by detecting the voltage generated across resistor R4 using control IC42, it is also possible to detect the current flowing through MOSFETQ1 when MOSFETQ1 is ON.

[0028] The MOSFET driver 45 is a driver for switching control. The MOSFET driver 45 drives MOSFETQ1 and MOSFETQ2, respectively, based on signals transmitted from the control IC 42. Since the MOSFET driver 45 can output a higher voltage than the control IC 42, using the MOSFET driver 45 allows for more stable switching control than directly driving MOSFETQ1 from the control IC 42.

[0029] The control power supply circuit 43 steps down the voltage across capacitor C2. This stepped-down voltage is further smoothed by capacitor C4 to generate the control power supply for the MOSFET driver 45. Hereafter, the control power supply for the MOSFET driver 45 generated by the control power supply circuit 43 and capacitor C4 will be referred to as voltage V2. For example, voltage V2 is 15V. The control power supply circuit 43 may be a step-down converter circuit such as a buck converter circuit, or a step-up / step-down converter such as a flyback circuit.

[0030] The step-down circuit 44 further steps down the voltage V2 to generate the operating power supply voltage for the control IC 42. The operating power supply voltage is, for example, 5V. The operating power supply voltage is input to the VDD terminal of the control IC 42.

[0031] The control IC42 is a microcontroller, or a composite IC containing a microcontroller and a driver. Alternatively, it can be composed of a processing unit such as a DSP (Digital Signal Processor).

[0032] The control IC 42 detects the DC voltage V1 being charged to capacitor C2 from the P1 terminal and performs feedback control to keep the DC voltage constant. In the feedback control, the control IC 42 sends a signal to the MOSFET driver 45 from the Vg1 terminal to control the switching of MOSFET Q1.

[0033] Furthermore, since it is necessary to keep the duration of the signal that turns on MOSFETQ1 constant while also performing feedback control, the feedback period must be slower than the period of the AC-derived voltage.

[0034] Furthermore, the control IC 42 sends a signal from the Vg2 terminal to the MOSFET driver 45 to control the switching of MOSFET Q2 so that the voltage across resistor R4 remains constant. This enables constant current control of the buck converter circuit 46 described above.

[0035] The LED light source unit 50 has a structure in which multiple LED light sources are connected in series. The LED light source unit 50 receives a DC voltage generated by the buck converter circuit 46 and capacitor C3. This causes the LED light sources to light up.

[0036] In this embodiment of the lighting device 100, the input unit 10 accepts both alternating current (AC) and direct current (DC) inputs. Furthermore, the conversion circuit 40 converts the input AC or DC voltage into a DC voltage suitable for driving the LED light source unit 50. The conversion circuit 40 then supplies this DC voltage to the LED light source unit 50, causing the LED light source to light up.

[0037] <Variations> In Figure 1, the case where the conversion circuit 40 is a combination of a boost chopper circuit 41 and a buck converter circuit 46 was explained. However, any type of circuit that converts the input AC voltage or DC voltage to a voltage suitable for driving the LED light source unit 50 is acceptable. This point is also common to all of the following embodiments.

[0038] Figure 2 is a flowchart showing the processing performed by the lighting device according to Embodiment 1 of this disclosure. First, the control IC 42 starts processing (step S21). Next, the control IC 42 determines whether or not a voltage has been applied to the input detection circuit 30 (step S22). If the application of voltage is detected, the control IC 42 performs the input voltage determination process described above (step S23). The input voltage determination process in step S23 is performed within a certain time. Hereafter, the time during which the input voltage determination process is performed will be referred to as the first determination time. The first determination time is, for example, 300ms, but the time can be freely set.

[0039] If the input voltage determination process determines that the voltage is AC, it means that the lighting device 100 is in its normal operating environment. Therefore, the control IC 42 controls the lighting of the LED light source 50 so that a first brightness is achieved (step S24). Here, the first brightness is the brightness required in the normal operating environment of the lighting device 100.

[0040] On the other hand, if the input voltage determination process determines that the voltage is DC, it means that the lighting device 100 is in an emergency operating environment. Therefore, the control IC 42 controls the lighting of the LED light source 50 so that a second brightness level is achieved (step S25). The second brightness level is the minimum brightness required in an emergency and is dimmer than the first brightness level. In this way, by reducing the brightness to the minimum level required in an emergency, battery consumption can be suppressed and the lighting time of the lighting device 100 can be extended. In addition, suppressing battery consumption means that the number of lighting devices 100 that can be connected to one battery can be increased, thus improving the efficiency of the equipment.

[0041] As explained in the flowchart above, the lighting device 100 of this embodiment controls the lighting of the LED light source 50 with different brightness levels depending on whether the input to the input unit 10 is an alternating current voltage (AC) or a direct current voltage (DC). This makes it possible to achieve the necessary brightness levels depending on whether the operating environment of the lighting device 100 is under normal conditions or an emergency condition.

[0042] <Variations> Furthermore, the second brightness does not necessarily have to be the minimum brightness required in an emergency. The second brightness may be brighter than the first brightness, and should be determined in a way that is suitable for the operating environment of the lighting device 100. This point is also common to all of the following embodiments.

[0043] Furthermore, if the application of voltage to the input detection circuit 30 is detected in step S22, a process to determine the level of said voltage may be performed. This point is common to all the embodiments described below.

[0044] Embodiment 2 The lighting device 100 in this embodiment is the same as in Embodiment 1, but the processing performed differs from that in Embodiment 1. Figure 3 is a flowchart showing the processing performed by the lighting device according to Embodiment 2 of this disclosure. First, the control IC 42 starts processing (step S31). Next, the control IC 42 determines whether or not a voltage has been applied to the input detection circuit 30 (step S32). If the application of voltage is detected, unlike in Embodiment 1, the control IC 42 controls the lighting of the LED light source unit 50 at a specified brightness (step S33).

[0045] Furthermore, the control IC 42 performs an input voltage determination process (step S34). The input voltage determination process in step S34 is performed within a certain time. Hereafter, the time taken to perform steps S33 and S34 will be referred to as the second determination time. The second determination time is, for example, 300 ms.

[0046] The processing from step S34 onward is the same as in Embodiment 1. That is, if the input voltage determination process determines that the voltage is AC, the control IC 42 controls the LED light source unit 50 to light up so that the first brightness is achieved (step S35). On the other hand, if the voltage is DC, the control IC 42 controls the LED light source unit 50 to light up so that the second brightness is achieved (step S36).

[0047] Thus, the lighting device 100 of this embodiment controls the LED light source unit 50 to light up at a predetermined brightness until the input voltage determination process is completed, regardless of whether the input to the input unit 10 is an alternating current voltage (AC) or a direct current voltage (DC). This makes it possible to light up the LED light source unit 50 without waiting for the result of the input voltage determination process.

[0048] Embodiment 3 Figure 4 is a circuit block diagram of a lighting device according to Embodiment 3 of the present disclosure. In this embodiment, the lighting device 100 of Embodiment 1 further comprises a setting device 60 and a setting detection circuit 70. The setting device 60 is a device in which the user inputs lighting conditions such as dimming rate, and can be a controller, remote control, wall switch, etc. The setting detection circuit 70 converts the lighting conditions transmitted from the setting device 60 into a signal that can be detected by the control IC 42, and inputs the converted signal to the P4 terminal of the control IC 42. As a result, the control IC 42 can control the lighting of the LED light source unit 50 so that the lighting conditions received from the setting device 60 are realized.

[0049] Thus, the lighting device 200 of this embodiment performs lighting control based on the lighting conditions input to the setting device 60.

[0050] Figure 5 is a flowchart showing the process performed by the lighting device according to Embodiment 3 of this disclosure. In Figure 5, the process from step S51 to step S53, which determines the input voltage, is the same as in Figure 2 of Embodiment 1.

[0051] However, if the input voltage determination process determines that the voltage is AC, unlike in Embodiment 1, the control IC 42 further determines whether or not lighting conditions have been input to the control IC 42 from the setting device 60 (step S54). If the input of lighting conditions is confirmed, the control IC 42 sets the brightness based on those lighting conditions as the first brightness and controls the lighting of the LED light source unit 50 (step S55).

[0052] On the other hand, if the input voltage determination process determines that the voltage is DC, the control IC 42 controls the lighting of the LED light source unit 50 to achieve a second brightness level, similar to the first embodiment (step S56). In this way, the control IC 42 does not refer to the input lighting conditions in an emergency situation and performs control that does not depend on the lighting conditions. This ensures that the LED light source unit 50 is reliably lit even in an emergency situation, and that a minimum level of brightness is secured.

[0053] As explained in the flowchart above, in addition to the processing described in Embodiment 1, the lighting device 200 of this embodiment, in a normal usage environment, refers to the lighting conditions set by the user and sets the brightness based on those lighting conditions as the first brightness. This makes it possible to realize the lighting conditions set by the user.

[0054] <Variations> Furthermore, if the application of voltage to the input detection circuit 30 is detected in step S52, the control IC 42 may control the lighting of the LED light source unit 50 at a specified brightness before the input voltage determination process in step S53 (step S57). In other words, the same process as in Embodiment 2 may be added.

[0055] Embodiment 4 Figure 6 is a circuit block diagram of a lighting device according to Embodiment 4 of the present disclosure. The lighting device 300 in this embodiment is the same as in Embodiment 3, but the setting unit 60 further includes a distance sensor 61 that measures the distance between the floor and the lighting device 200, i.e., the installation height of the lighting device 200. The information on the installation height of the lighting device 200 measured by the distance sensor 61 is transmitted from the setting unit 60 to the setting detection circuit 70, similar to the lighting conditions described above. Furthermore, in the setting detection circuit 70, it is converted into a signal format that can be detected by the control IC 42.

[0056] Figure 7 is a flowchart showing the process performed by the lighting device according to Embodiment 4 of the present disclosure. The flowchart in Figure 7 is the same as in Figure 5, but if the input voltage determination process in step S73 determines that the voltage is DC, the control IC 42 further determines whether or not the installation height of the lighting device 200 has been input (step S76). If the input is confirmed, the second brightness is increased in proportion to the installation height of the lighting device, and the LED light source unit 50 is controlled to light up so that the second brightness is achieved (step S77).

[0057] As explained in the flowchart above, in addition to the processing described in Embodiment 3, the lighting device 300 of this embodiment performs lighting control based on the installation height of the lighting device 200 in emergency operating environments. This ensures that the floor surface is illuminated with the minimum necessary brightness even in emergency situations, regardless of the height at which the lighting device 200 is installed.

[0058] <Variations> The setting device 60 does not necessarily have to be equipped with a distance sensor 61. The user may input the installation height of the lighting device 300, which has been measured in advance, into the setting device 60, and in that case, the same effect as described above can be obtained.

[0059] Furthermore, if the application of voltage to the input detection circuit 30 is detected in step S72, the control IC 42 may control the lighting of the LED light source unit 50 at a specified brightness before the input voltage determination process in step S73 (step S78). In other words, the same process as in Embodiment 2 may be added.

[0060] As described above, this disclosure provides a lighting fixture that adjusts the brightness and lights up the light source depending on whether the input is an AC voltage or a DC voltage. [Explanation of symbols]

[0061] Input section 10; Rectifier 20; Input detection circuit 30; Conversion circuit 40; Boost chopper circuit 41; Control IC 42; Control power supply circuit section 43; Step-down circuit section 44; MOSFET driver 45; Buck converter circuit 46; LED light source section 50; Setting device 60; Distance sensor 61; Setting detection circuit 70; Lighting device 100; Lighting device 200; Lighting device 300

Claims

1. A lighting device that accepts both AC and DC voltage inputs and lights up a light source, A reception process that receives voltage from the power supply, The input voltage determination process in the aforementioned reception process determines whether the received voltage is an AC voltage or a DC voltage, If the received voltage is an AC voltage, the light source is turned on to achieve the first brightness level. If the received voltage is a DC voltage, A process of referring to the installation height of the aforementioned lighting device, A process of turning on the light source so that a second brightness is achieved, which is dimmer than the first brightness and becomes brighter as the installation height increases; A lighting device configured to perform the following actions.

2. It also has a setting device, If the received voltage is an AC voltage, the process involves referring to the lighting conditions set by the setting device. A process to set the brightness based on the aforementioned lighting conditions to the first brightness, Further execution, If the received voltage is a DC voltage, The lighting device according to claim 1, wherein the light source is turned on to achieve the second brightness without referring to the lighting conditions set by the setting device.

3. The setting device further includes a sensor for measuring the installation height of the lighting device, The lighting device according to claim 2, wherein, in the process of referring to the installation height of the lighting device when the received voltage is a DC voltage, the installation height of the lighting device measured by the sensor is referred to.

4. The lighting device according to any one of claims 1 to 3, wherein until the input voltage determination process is completed, the process of turning on the light source at a specified brightness is performed.

5. The lighting device according to claim 1, wherein the input voltage determination process determines whether the received voltage is an AC voltage or a DC voltage according to the time change of the received voltage.

6. Equipped with an additional conversion circuit, The conversion circuit, if the received voltage is an AC voltage, converts the received voltage to a DC voltage suitable for lighting the light source. The lighting device according to claim 1, wherein if the received voltage is a DC voltage, the received voltage is converted to a DC voltage suitable for lighting the light source.

7. The lighting device according to claim 6, wherein the conversion circuit is a switching circuit comprising a switching element.

Images