Method for controlling LED lighting and lighting device using the same.

Abstract

In an LED lighting control method that drives an LED array driven by a full-wave rectified pulsating current, with the power supply end on the near end and multiple LEDs connected in series from the power supply end to the far end, a first power supply point is provided on the near end, and a second power supply point is provided at an LED connection point where the number of LEDs connected in series from the near end is greater than the number of LEDs counted from the far end. While the instantaneous voltage of the pulsating current is low, a first LED lighting control operation is performed to light up the LEDs connected from the second power supply point toward the far end according to the magnitude of the instantaneous value. After all LEDs from the second power supply point to the furthest LED are lit, a second LED lighting control operation is performed to light up more LEDs than the number of LEDs that have been lit up, from the first power supply point on the near end to the furthest end, according to the instantaneous value of the pulsating current. When the instantaneous value of the pulsating current voltage changes from increasing to decreasing, the first and second lighting control operations are performed in the reverse order. (Figure 1)

Description

Technical Field

[0001] The present invention relates to a method for controlling LED lighting that utilizes pulsating current obtained by full-wave rectifying alternating current to light an LED without using a DC power supply, and a lighting device using the same.

Background Art

[0002] LED lighting has the characteristics of long life and low power consumption compared to conventional lighting fixtures such as fluorescent lamps and incandescent bulbs. Therefore, as a lighting device that replaces fluorescent lamps and incandescent bulbs for improving the living environment through energy conservation and thus preventing global warming, it has been rapidly spreading in various fields.

[0003] However, many LED lights use a DC power supply that outputs a constant voltage to operate long-life LEDs. Generally, in a DC power supply, after rectifying and smoothing the input alternating current and then converting it to high frequency, it undergoes step-down, rectification, and smoothing to obtain the desired DC voltage, and negative feedback control is used to obtain a stable DC voltage. In addition, a large-capacity electrolytic capacitor is used for smoothing after rectification, and multiple capacitors may be used. By the way, when calculating the life of a DC power supply, the electrolytic capacitor used has the characteristic that its life is halved for every 10°C increase in ambient temperature. Therefore, together with the failure and life of components other than the electrolytic capacitor of the DC power supply, it is necessary to consider the life and failure of the electrolytic capacitor. At present, even when using long-life LEDs, the life of the lighting device is determined by the life and failure rate of the DC power supply used in the device.

[0004] In addition, a DC power supply uses many components to reduce harmonics generated when rectifying and smoothing the input alternating current, and radiated noise generated due to high-frequency operation inside the power supply. Although it is a means by which small and stable DC can be easily obtained, the extension of the life of the DC power supply, the simplification of the method for reducing harmonics and unnecessary radiated noise, etc. are still unsolved problems since the emergence of LED lighting. Therefore, solutions for solving the above problems of conventional LED lighting have been explored.

[0005] Therefore, in order to maximize the inherently extremely long lifespan characteristics of LEDs, LED lighting technology has also been disclosed that utilizes pulsating current obtained by full-wave rectification of AC to light the LEDs without using a DC power supply (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 5486698 describes the conventional AC-driven LED drive control method, cited as reference document 1 above, with reference to drawings. Figure 5 is an example of a circuit diagram for explaining this conventional AC-driven LED drive control method, and Figure 6 shows the LED lighting state according to this circuit diagram (Figure 5). The conventional AC-driven LED drive control method will be explained below with reference to these. In order to facilitate understanding of the present invention, including this figure and other drawings, the number of LEDs is exemplarily set to 10 and the AC voltage fluctuation to ±10% in this explanation, prioritizing the clarity of the text and drawings. However, it should be emphasized that even with a relatively low AC voltage of 100V, the peak value is approximately 141V, so in actual LED lighting, roughly 50 to 60 LEDs are required, and the number of LEDs will differ depending on the AC voltage. However, if dozens of LEDs are shown in the drawing, the drawing will become complicated and difficult to understand. Therefore, in the explanation of this invention, the number of LEDs in the drawing will be 10 as an example, and the operation will be explained in the following numbered order. 1. Even if the pulsating voltage is low and two LEDs do not light up, SW1-6 remain closed. The pulsating voltage gradually rises, and LEDs 1 and 2 light up. At this point, the pulsating voltage is low and LEDs 3-10 cannot light up. Continue this operation as long as the pulsating voltage is low and LEDs 1-4 are not lit, and move to the next operation when the pulsating voltage rises and LEDs 1-4 can light up. 2. When the pulsating voltage rises further and four LEDs can light up, open SW1. Since SW2 remains closed, LEDs 1-4 light up, but the pulsating voltage is still low and LEDs 5-10 do not light up. Continue this operation as long as the pulsating voltage is low and LEDs 1-6 are not lit, and move to the next operation when the pulsating voltage rises and LEDs 1-6 can light up. Furthermore, if LEDs 1-4 cannot remain lit, the switches are returned to their original positions and the operation returns to the previous state. 3. When the pulsating voltage rises further and it becomes possible to light up all 6 LEDs, SW2 is opened. Since SW3 remains closed, LEDs 1-6 light up. The pulsating voltage is low and LEDs 7-10 do not light up. This operation continues as long as the pulsating voltage is low and LEDs 1-8 are not lit, and when the pulsating voltage rises and LEDs 1-8 can light up, the operation moves to the next step. Furthermore, if LEDs 1-6 can no longer remain lit, the switches are returned to their original positions and the operation returns to the previous state.4. When the pulsating voltage rises further and all 8 LEDs can light up, open SW3. SW4 remains closed, so LEDs 1-8 light up. The pulsating voltage is low, so LEDs 9-10 do not light up. Continue this operation as long as the pulsating voltage is low and LEDs 1-9 are not lit. When the pulsating voltage rises and LEDs 1-9 can light up, move to the next operation. Also, when LEDs 1-8 can no longer remain lit, return the switches to their original positions and return to the previous operation. 5. When the pulsating voltage rises further and all 9 LEDs can light up, open SW4. SW5 remains closed, so LEDs 1-9 light up. The pulsating voltage is low, so LED 10 does not light up. Continue this operation as long as the pulsating voltage is low and LEDs 1-10 are not lit. When the pulsating voltage rises and LEDs 1-10 can light up, move to the next operation. Also, when LEDs 1-9 can no longer remain lit, return the switches to their original positions and return to the previous operation. 6. When the pulsating voltage rises further and it becomes possible to light up all 10 LEDs, open SW5. Since SW6 remains closed, all LEDs from LED1 to LED10 will light up. Continue the operation of lighting LEDs from LED1 to LED10, but when it becomes impossible to light up LEDs from LED1 to LED10, return the switches to their original positions and return to the previous operation.

[0007] Furthermore, once the maximum number of LEDs that can be lit with the current has been reached, the current will begin to decrease, and thereafter, the reverse of the previous operation should be performed. [Overview of the project] [Problems that the invention aims to solve]

[0008] Figure 6 is an explanatory diagram showing the LED lighting state when the LED drive control method based on the drawing in Figure 5 is implemented using the AC drive method. In this explanatory diagram, the pulsating voltage is explained using the operation from the start of the voltage rise after the voltage has dropped completely as an example. The SW state is maintained unless otherwise instructed. The specific procedure for opening and closing the switches is shown for when the opening and closing operations of each SW (switch) shown in Figure 5 are performed according to the procedures 1 to 7.

[0009] Conventional AC-driven LED lighting supplies power to the LEDs from a fixed point and increases or decreases the number of lit LEDs according to the pulsating instantaneous voltage. Therefore, when the pulsating instantaneous voltage is high, the number of lit LEDs increases, and when the pulsating instantaneous voltage is low, the number of lit LEDs decreases. Consequently, LEDs close to the power supply point remain lit even when the AC voltage drops, but LEDs farther from the power supply point gradually turn off starting from the furthest LED as the voltage drops, and this extinguishing is visible to the naked eye.

[0010] This will be explained using the diagram to illustrate the lighting state of conventional AC-driven LED lighting. Figure 6 is a diagram showing the LED lighting status according to voltage fluctuations when all 10 LEDs are lit at the maximum AC voltage using the conventional AC driving method. This driving method aims to help understand the technology of controlling the lighting of LEDs with the pulsating current obtained by full-wave rectifying the AC input. The specific procedure for opening and closing the switches is shown by opening and closing each SW (switch) shown in Figure 5 according to the procedures 1 to 7 described above.

[0011] Regarding the diagram, Figure 6(a) on the left shows the state when the voltage rises (see the peak shown by the solid line representing the pulsating current at nominal voltage + 10%). At the peak of this peak shown by the solid line at nominal voltage + 10%, it can be seen that all of LED1 to LED10, which are exemplified for the explanation of the present invention, are lit.

[0012] Furthermore, Figure 6(b) in the middle shows the state at standard voltage (see the peak shown by the solid line representing the pulsating current at nominal voltage ±0%). At the peak of the solid line representing nominal voltage ±0%, it can be seen that LEDs 1 to 9, which are exemplified for the explanation of the present invention, are lit, while LED 10 is off.

[0013] Furthermore, Figure 6(c) on the right shows the state when the voltage drops (see the peak shown by the solid line representing the pulsating current at nominal voltage -10%). At the peak shown by the solid line at nominal voltage -10%, it can be seen that LEDs 1 to 8, which are exemplified for the explanation of the present invention, are lit, while LEDs 9 and 10 are off.

[0014] Therefore, in order to avoid a situation where some of the LEDs in the LED lighting are visibly turned off, conventional LED lighting control methods were employed that ensured all LEDs remained lit even when the AC voltage dropped (that is, regardless of the supply voltage in Figure 6, which is a diagram illustrating the problem of the present invention, only 8 LEDs are installed and all LEDs 1 to 8 are lit).

[0015] The problem with adopting this control method is that it requires controlling the LED lighting to match the lowest pulsating voltage. As a result, the voltage difference between the currently operating AC supply voltage and the lowest AC supply voltage cannot contribute to light emission and becomes a loss. Therefore, improving lighting efficiency and reducing the losses required to achieve this is inherently difficult.

[0016] The above problems can be explained in more detail as follows: In conventional AC-driven LED lighting, as mentioned above, the number of LEDs that light up starting from the power supply point increases when the peak voltage of the pulsating current is high, and decreases when it is low. Therefore, LEDs close to the power supply point remain lit even when the peak voltage of the pulsating current decreases, but LEDs further away gradually become lit for shorter periods as the peak voltage of the pulsating current decreases, and eventually turn off.

[0017] As the AC voltage drops, the LEDs sequentially turn off starting from the furthest end of the power supply point, and this can be visually confirmed. Therefore, conventional AC-driven LED lighting was designed so that all LEDs would light up even when the input AC voltage was at its lowest, thus eliminating LEDs that would not light up during voltage drops.

[0018] This is to eliminate non-illuminating LEDs when the supply voltage drops within the nominal fluctuation range, preventing the LED lighting from being mistaken for a malfunction. For the reasons above, even if the AC voltage is higher than the lower limit of the nominal fluctuation range, the difference between the lower limit and the current supply voltage cannot be utilized and becomes a loss, not contributing to light emission.

[0019] Therefore, conventional AC-driven systems have the difficult problem of making it difficult to improve lighting efficiency, and the portion that is lost cannot be used to improve efficiency.

[0020] The object of the present invention is to provide an LED lighting control method that utilizes pulsating current obtained by full-wave rectification of AC without using a DC power supply to light the LEDs, which has an extremely long product life, excellent luminous efficiency, and makes efficient use of power energy, and by lighting all LEDs even when there are voltage fluctuations, it is possible to reduce the losses of LED lighting and improve efficiency compared to conventional methods, and to provide an LED lighting control method and lighting device using the same. [Means for solving the problem]

[0021] To solve the above-mentioned problems, the LED lighting control method according to claim 1 of the present invention is: This LED lighting method uses a pulsating current obtained by full-wave rectifying an AC voltage directly to light the LEDs, and includes an LED lighting control function that lights up an LED array formed by connecting multiple LEDs in series between the power supply end (near end) and the furthest end (farthest end). The device has a first power supply point on the near end, and a second power supply point at a connection point between LEDs where the number of LEDs connected in series from the near end is equal to or greater than the number of LEDs connected in series from the far end. When power is supplied from either the first power supply point or the second power supply point, a current switch is provided at a predetermined location between the LEDs connected from upstream to downstream that constitute the LED row, which measures the pulsating voltage at the time of power supply and lights up a number of LEDs corresponding to that pulsating voltage, and the opening and closing of these current switches is controlled. The pulsating voltage During startup By appropriately switching a predetermined current switch according to the degree of instantaneous voltage rise, the number of lit LEDs is increased downstream from the LED closest to the second power supply point, As the instantaneous voltage rises further, all the LEDs in the LED row, from the LED closest to the second power supply point to the furthest downstream LED, are lit. The aforementionedWhen the instantaneous voltage further rises to an instantaneous voltage capable of lighting all the LEDs sandwiched between the first power supply point and the second power supply point, power is supplied from the first power supply point instead of the second power supply point and at the same time the current switch is switched, so that all the LEDs sandwiched between the first power supply point and the second power supply point are lit. The aforementioned In the process of the instantaneous voltage further rising, the current switch is switched so that the number of lit LEDs increases further from the LED closest to the downstream side with respect to the second power supply point toward the far end side of the LED string in accordance with a further voltage rise corresponding to the further voltage rise. When the instantaneous voltage reaches the peak voltage of the pulsating current voltage and then starts to decrease, the current switch is appropriately switched to light the LEDs that can be lit in accordance with the instantaneous voltage that is decreasing from the LEDs lit by the peak voltage. When the instantaneous voltage drops below the instantaneous voltage at which all the LEDs between the first power supply point and the second power supply point can be lit, power is supplied from the second power supply point instead of the first power supply point, and the current switch is appropriately switched in accordance with the subsequent decrease in the instantaneous voltage so as to reduce the number of lit LEDs from the farthest LED on the most downstream side with respect to this second power supply point toward the closest LED. By controlling in this way, in any case of voltage rise or voltage drop within the fluctuation range of the AC power supply, all the LEDs in the LED string are surely lit at least once within the same pulsating current waveform, and the lighting control of each LED is performed within all the cycles of the pulsating current voltage.

[0022] Also, according to the LED lighting control method according to claim 2 of the present invention, in the LED lighting control method according to claim 1, Among the LEDs connected in series, at least one LED is characterized in that it is not constituted by a single LED itself but is constituted by connecting a plurality of LEDs in parallel. <000095>Also, according to the LED lighting control method according to claim 3 of the present invention, in the LED lighting control method according to claim 1, A switch for separation is provided between the second power supply point and the LED most closely connected thereto. 1 When performing the lighting control operation of 2nd the lighting control operation this switch is opened, and when performing the lighting control

[0023] Also, the LED lighting control method according to claim 4 of the present invention is the LED lighting control method according to claim 3, wherein instead of providing the switch, a diode that plays an equivalent role to the switch is provided.

[0024] Also, the LED lighting control method according to claim 5 of the present invention is a lighting device equipped with the control method described in any one of claims 1 to 4.

Effect of the Invention

[0025] According to the present invention, there is provided a control method for LED lighting that uses pulsating current obtained by full-wave rectification of alternating current instead of using a direct current power supply to light an LED, having an extremely long product life, excellent luminous efficiency, and making efficient use of power energy without waste. By lighting all LEDs even during voltage fluctuations, it is possible to reduce the loss of LED lighting and improve the efficiency compared to the prior art, and to provide a control method for LED lighting and a lighting device using the same.

Brief Description of the Drawings

[0026] [Figure 1] It is a circuit diagram of an LED lighting control circuit that forms the basic configuration of the present invention. [Figure 2] It is a characteristic diagram for explaining the LED lighting control method according to the present invention. [Figure 3] It is a circuit diagram of an LED lighting control circuit according to the first embodiment of the present invention. [Figure 4] It is a circuit diagram of an LED lighting control circuit according to the second embodiment of the present invention. [Figure 5] It is a conventional LED lighting control circuit diagram. [Figure 6] This is a characteristic diagram illustrating a conventional LED lighting control method. [Modes for carrying out the invention]

[0027] The following describes the essential basic configuration features of the LED lighting control method according to the present invention (hereinafter referred to as the "new AC drive method" as appropriate). To facilitate understanding, Figure 1 (circuit diagram) and Figure 2 (characteristic diagram) will be used. Figure 1 shows a schematic diagram of the circuit realizing the new AC drive method according to the present invention, and a schematic configuration of an LED lighting device using this circuit. Figure 2 is an explanatory diagram showing the LED lighting state using the new AC drive method based on the schematic configuration shown in Figure 1.

[0028] The new AC drive method according to the present invention has two main features: firstly, it dynamically changes the lighting area of ​​the LED array in response to the instantaneous voltage of the pulsating current; secondly, while conventional AC drive methods only light up the LEDs when the instantaneous voltage of the pulsating current obtained by full-wave rectifying the supplied AC voltage is high, the new AC drive method according to the present invention lights up the LEDs even when the instantaneous voltage is low; and secondly, it is a driving method that lights up all LEDs within the same pulsating current cycle even if the AC voltage fluctuates within a predetermined range. Furthermore, by utilizing the AC voltage fluctuations that could not be used in the past to contribute to LED lighting, this new AC drive method achieves a significant improvement in lighting efficiency and a reduction in losses compared to conventional AC drive methods used in LED lighting control.

[0029] In conventional AC drive methods, all LED rows are lit when the AC voltage is at the lower limit of its fluctuation range. As a result, the current and its peak value are limited to the value at the lower limit of the AC voltage and do not flow beyond that. Even if the supplied AC voltage increases, the current waveform plateaus. However, in the new AC drive method of the present invention, the waveform does not plateau until the instantaneous voltage determined by the lighting of all LEDs is reached. This results in a current waveform that approximates the input voltage waveform, and even during voltage fluctuations, the current waveform approximates a sinusoidal wave in accordance with the voltage fluctuation, making it possible to achieve further harmonic reduction.

[0030] The following describes the conceptual diagram of the operation of the new AC drive method of the present invention. Figure 1 is a schematic configuration diagram for realizing a specific lighting control method of the new AC drive method according to the present invention. In order to facilitate understanding of the present invention, the LEDs depicted in the drawings, as in Figures 3 to 5, are shown as an example, with 10 LEDs connected in series, which is fewer than the actual number of LEDs, and switches for realizing the functions of the present invention are shown placed in predetermined locations.

[0031] Furthermore, the control function unit is shown as a block diagram, and the specific and illustrative configuration of this control function will be described in the first and second embodiments described later.

[0032] Next, an example of the procedure for a specific lighting control method of the new AC drive method according to the present invention will be explained in accordance with the configuration in Figure 1. In the following explanation, the instantaneous voltage of the pulsating current will be explained using the operation from the start of the voltage rise after the voltage has dropped as an example. In the following explanation, the SW state will remain as is unless instructed otherwise, but the opening and closing of the SW may be left to the user's discretion if there is no effect on anything else. The switching of each switch shown in Figure 1 will be performed using the switching procedure unique to the present invention. Specifically, in the configuration shown in Figure 1, the LEDs will be driven according to the following procedures 1 to 7. 1. While the instantaneous voltage of the pulsating current is low and the two LEDs do not light up, close PSW01, open PSW02, close SW1, and open the other switches. The instantaneous voltage of the pulsating current will gradually increase, and eventually LEDs 7 and 8 will light up. 2. When the instantaneous voltage of the pulsating current rises further and reaches a voltage that can light up all four LEDs, open SW1 and close SW2. For the other switches, PSW01 remains closed, PSW02 remains open, and SW3 and SW14-16 remain open. This operation continues as long as the instantaneous voltage of the pulsating current is low and LEDs 1-6 are not lit. When the instantaneous voltage of the pulsating current rises and LEDs 1-6 can be lit, the operation moves to the next step. If LEDs 1-4 cannot be kept lit, the switches are returned to their original state and the operation returns to the previous state. 3. When the instantaneous voltage of the pulsating current rises further and reaches a voltage sufficient to light up all six LEDs, open SW2, close SW3, open PSW01, and close PSW02. For the other switches, SW1 remains open, and SW14-16 remain open. This operation continues as long as the instantaneous voltage of the pulsating current is low and LEDs 1-8 are not lit. When the instantaneous voltage of the pulsating current rises and LEDs 1-8 can be lit, the operation moves to the next step. If LEDs 1-6 cannot be kept lit, the switches are returned to their original positions and the operation returns to the previous state. 4. When the instantaneous voltage of the pulsating current rises further and reaches a voltage sufficient to light up all eight LEDs, open SW3 and close SW14. For the other switches, PSW01 remains open, PSW02 remains closed, SW1-2 remain open, and SW15-16 remain open. This operation continues as long as the instantaneous voltage of the pulsating current is low and LEDs 1-9 are not lit. When the instantaneous voltage of the pulsating current rises and LEDs 1-9 can be lit, the operation moves to the next step. If LEDs 1-8 cannot be kept lit, the switches are returned to their original positions and the operation returns to the previous state. 5. When the instantaneous voltage of the pulsating current rises further and reaches a voltage sufficient to light up all nine LEDs, open SW14 and close SW15. For the other switches, PSW01 remains open, PSW02 remains closed, SW1-3 remain open, and SW16 remains open. This operation continues as long as the pulsating current instantaneous voltage is low and LEDs 1-10 are not lit. When the pulsating current voltage rises and LEDs 1-10 can light up, the operation moves to the next step. If LEDs 1-9 cannot be kept lit, the switches are returned to their original positions and the operation returns to the previous state. 6. When the instantaneous voltage of the pulsating current rises further and it becomes possible to light up all 10 LEDs, open SW15 and close SW16. This will light up all LEDs from LED1 to LED10. The other switches will remain as follows: PSW01 will remain open, PSW02 will remain closed, and SW1-3 and SW14-15 will remain open. This operation will continue as long as LEDs 1-10 are lit. 7. From this point onward, the instantaneous voltage of the pulsating current will begin to decrease after reaching its peak value, so the operation will be reversed from before.

[0033] Furthermore, as a special note regarding the operation explanations for 1 to 7, PSW02 is provided for the purpose of separating LED6 and 7 when PSW01 is closed and preventing reverse voltage from being applied to LED6. It should be noted that if the forward voltage drop of the diode is within the acceptable range, it can be replaced with a diode. Figure 2 is a diagram illustrating the LED lighting status according to voltage fluctuations when the new AC drive method of the present invention is designed so that all 10 LEDs light up when the AC voltage is at its maximum. It is illustrated to help understand the technology of controlling LED lighting with the pulsating current obtained by full-wave rectifying the AC input. Figure 2(a) on the left shows the state when the AC input voltage is at its maximum (nominal voltage +10%), Figure 2(b) in the middle shows the state when the AC input voltage is at its standard (nominal voltage ±0%), and Figure 2(c) on the right shows the state when the AC input voltage is at its minimum (nominal voltage -10%).

[0034] According to this diagram, the new AC drive method, when designed considering an AC voltage fluctuation range, for example ±10%, allows all LEDs to light up within the same pulsating waveform even when the voltage rises or falls. This demonstrates that by utilizing the voltage fluctuation section that was previously unusable, a significant efficiency improvement (for example, about 10%) can be achieved.

[0035] Next, a specific and illustrative detailed description of the new AC drive method according to the present invention will be presented as the first and second embodiments. First, the first embodiment will be described. The first embodiment is a digital control implementation of the new AC drive method according to the present invention. Figure 3 is a diagram that shows the control details of the new AC drive method according to this first embodiment in more detail than Figure 1. The details of the control will be described below.

[0036] The drive control unit is equipped with an ADC for voltage measurement. The ADC for voltage measurement has the function of converting analog input signals into digital signals (i.e., Analog to Digital Converter), and will be referred to simply as "ADC" below.

[0037] In the present invention illustrated in this first embodiment (hereinafter simply referred to as "the present invention"), the ADC has the function of converting two analog input signals, In1 and In2, into digital signals. The ADC then selects one of In1 and In2 according to the instructions of the MCU (described later), converts the selected analog signal into a digital signal, and reports its value to the MCU.

[0038] Furthermore, the drive control unit is equipped with a DAC for setting the current value. The DAC has the function of converting a digital input signal into an analog voltage signal (i.e., a Digital to Analog Converter), and will be simply referred to as "DAC" below.

[0039] Furthermore, the drive control unit is equipped with a microcontroller unit (hereinafter simply referred to as "MCU"), which controls the lighting of all LEDs. More specifically, an ADC for voltage measurement is used to collect the instantaneous voltage of the pulsating current, and the necessary switches are instructed to open and close via the switch control unit. At the same time, a DAC for current value setting is used to control the gate voltage of the metal oxide field-effect transistor (hereinafter simply referred to as "MOS") MOS1, thereby controlling the current value ID flowing through MOS1 to be within a predetermined range.

[0040] Furthermore, the drive control unit controls the opening and closing of all switches via the switch control unit according to instructions from the MCU. The switches have a PSW1 that controls the power supply point of the LEDs, and a function to open and close switches CSW14, CSW26, CSW3, and CSW5, which are connected to multiple lead ends drawn from multiple locations in the LED row, in order to drive a preset number of LEDs according to the instantaneous voltage of the pulsating current, and connect them to the drain of the drive MOS1.

[0041] Furthermore, as mentioned above, the drive control unit controls the current ID flowing through MOS1 by controlling the gate voltage applied to MOS1. To go into a little more detail, the MCU measures the voltage across resistor RD with the ADC and calculates the current value ID by dividing the obtained value by the value of RD. The MCU compares the calculated ID with a target value it holds internally. If the difference is within a predetermined range, the DAC setting remains unchanged. If the difference is small and outside the predetermined range, the DAC setting value is increased by a predetermined value. If the difference is large and outside the predetermined range, the DAC setting value is decreased by a predetermined value. This process is performed on the DAC. Through this operation, the MCU can manipulate the gate voltage of MOS1 and control the current (ID) flowing through MOS1 to stay within the set range.

[0042] Please note that Figure 3 is merely an explanatory diagram of the operation overview of the new AC drive method according to the present invention, and therefore does not show components necessary for stable operation, such as resistors and capacitors. This figure is merely an illustrative diagram intended to facilitate understanding of the invention and does not guarantee stable operation or explain standards for performance, function, etc.

[0043] Next, the operation of the new AC drive method using digital control according to the second embodiment of the present invention described above will be explained. Specifically, the operation is started by following the procedure below. (Operation 1) Before starting LED lighting control, the MCU must first be configured to enable operation. Next, the MCU will configure the necessary settings for its peripherals. Specifically, this involves issuing an instruction to the switch control unit to open all switches, adjusting the output of the current value setting DAC to ensure the current of MOS1 is within the allowable range according to pre-set information, and initializing the voltage measurement ADC and, if necessary, reacquiring voltage information. Needless to say, we will not interfere with any other actions that we deem necessary, other than those mentioned above. Furthermore, if it is clear that the operation in question has absolutely no effect on anything else, the switch in question may not perform the instructed operation, and the same shall apply thereafter. (Operation 2) Next, the MCU prepares to control the LED lighting. First, the beginning of the rising edge of the pulsating voltage is detected. To do this, an ADC for voltage measurement is used to measure In1 (pulsating voltage) (more precisely, the instantaneous voltage of the pulsating current), and then the voltage value of In2 (voltage generated across resistor RD due to the ID of MOS1) is measured. Then, when it is confirmed that the value of In1 exceeds a preset range and In1 continues to decrease or increase, it is determined that the instantaneous voltage of the pulsating current has started to rise or fall. Furthermore, the determination of instantaneous voltage increases and decreases in pulsating current will be carried out in the same manner going forward. re This is referred to as the rise and fall of pulsation. It should also be noted that the measurement of In1 and In2 is an action that should be performed continuously without any additional instructions. This operation continues until the instantaneous voltage of the pulsating current begins to rise and the measured pulsating current voltage In1 reaches a voltage equal to or greater than the preset lighting voltage (reference voltage 2) of LEDs 7-8. (Operation 3) The MCU closes PSW1 and CSW14 to light up LEDs 7 and 8, then compares the terminal voltage In2 of RD with the value of (set current value for LEDs 7 and 8) × (resistance value of RD). If the value of In2 is lower than the aforementioned value, it increases the output of the current setting DAC by a preset value; if it is higher, it decreases it by a preset value. This process is repeated to control the current of LEDs 7 and 8 so that it remains within the set range. If upper and lower limits are set for the gate voltage applied to MOS1 or the output voltage of the current setting DAC, those conditions will also be followed. Furthermore, the instantaneous voltage value In1 of the pulsating current when the voltage value across resistor RD, generated by the current ID of MOS1, settles within the set range (In2), and the DAC reading value at that time are reflected as actual values ​​in the reference values, etc. (Other methods may be possible, but in this invention, it is simply reflected.) Then, if the measured pulsating voltage In1 is less than the preset ignition voltage (reference voltage 4) for LEDs 7-10, this operation continues. If In1 exceeds the reference voltage 4, the operation moves to the next step, and if In1 falls below the reference voltage 2, the operation returns to the previous step. (Operation 4) The MCU opens CSW14 and closes CSW26 to light up LEDs 7-10. PSW1 is then closed. Next, the terminal voltage In2 of RD is compared with the value of (set current value for LED7-10) × (resistance value of RD). If the value of In2 is lower than the aforementioned value, the output of the current setting DAC is increased by a preset value; if it is higher, it is decreased by a preset value. This operation is repeated to control the current of LED7-10 so that it remains within the set range. If upper and lower limits are set for the gate voltage applied to MOS1 or the output voltage of the current setting DAC, those conditions will also be followed. Furthermore, the pulsating voltage value In1 and the DAC instruction value at the time when the voltage value of resistor RD generated by In2, i.e., the current value ID of MOS1, settles within the set range will be reflected in the reference values, etc., as actual driving values ​​for LED7-10. The operation continues as long as the measured pulsating voltage In1 does not reach the preset illumination voltage (reference voltage 6) for LEDs 1-6. When In1 exceeds the reference voltage 6, the operation moves to the next step, and when In1 falls below the reference voltage value of 4, the operation returns to the previous step. (Operation 5) The MCU opens CSW26 and PSW1 and closes CSW3 to light up LEDs 1-6. It should be noted that in this explanation, a diode is installed between LEDs 6 and 7, and this is used as a substitute for the PSW02 switch function shown in Figure 1. Next, the terminal voltage In2 of RD is compared with the value of (set current value to flow through LED1-6) × (resistance value of RD). If the value of In2 is lower than the aforementioned value, the output of the current setting DAC is increased by a preset value; if it is higher, it is decreased by a preset value. This operation is repeated to control the current of LED1-6 so that it remains within the set range. If upper or lower limits are set for the gate voltage applied to MOS1 or the output voltage of the current setting DAC, those conditions will also be followed. Furthermore, the pulsating voltage value In1, which occurs when the voltage value across resistor RD, generated by the current value ID of MOS1, settles within the set range, and the DAC instruction value at that time, are reflected in the reference voltage, etc., as actual driving values ​​for LED1-6. The operation continues as long as the measured pulsating voltage In1 does not reach the preset illumination voltage (reference voltage 8) for LEDs 1-8. When In1 exceeds the reference voltage 8, the operation moves to the next step, and when the reference voltage falls below 6, it returns to the previous operation. (Operation 6) The MCU opens CSW3 and closes CSW14 to light up LEDs 1-8. Next, the terminal voltage In2 of RD is compared with the value of (set current value to flow through LED1-8) × (resistance value of RD). If the value of In2 is lower than the aforementioned value, the output of the current setting DAC is increased by a preset value; if it is higher, it is decreased by a preset value. This operation is repeated to control the current of LED1-8 so that it remains within the set range. If upper or lower limits are set for the gate voltage applied to MOS1 or the output voltage of the current setting DAC, those conditions will also be followed. Furthermore, the pulsating voltage value In1 and the DAC instruction value at the time when the voltage value of resistor RD generated by In2, i.e., the current value ID of MOS1, settles within the set range will be reflected in the reference voltage value, etc., as the actual driving values ​​for LED1-8. The operation continues as long as the measured pulsating voltage In1 does not reach the preset illumination voltage (reference voltage 9) for LED1 to LED9. When In1 exceeds the reference voltage 9, the next operation begins, and when the reference voltage falls below 8, the operation returns to the previous operation. (Operation 7) The MCU opens CSW14 and closes CSW5 to light up LEDs 1-9. Next, the terminal voltage In2 of RD is compared with the value of (set current value to flow through LED1-9) × (resistance value of RD). If the value of In2 is lower than the aforementioned value, the output of the current setting DAC is increased by a preset value; if it is higher, it is decreased by a preset value. This operation is repeated to control the current of LED1-9 so that it remains within the set range. If upper or lower limits are set for the gate voltage applied to MOS1 or the output voltage of the current setting DAC, those conditions will also be followed. Furthermore, the pulsating voltage value In1 and the DAC instruction value at the time when the voltage value across resistor RD, which is generated by the current value ID of MOS1, settles within the set range (In2), will be reflected in the reference voltage value, etc., as actual data from when LED1-9 were driven. Then, as long as the measured pulsating voltage In1 does not reach the preset ignition voltage (reference voltage 10) for LEDs 1 to 10, this operation continues. When In1 exceeds the reference voltage 10, the next operation begins, and when the reference voltage falls below 9, it returns to the previous operation. (Operation 8) The MCU opens CSW5 and closes CSW26 to light up LEDs 1-10. Next, the terminal voltage In2 of RD is compared with the value of (set current value to flow through LED1-10) × (resistance value of RD). If the value of In2 is lower than the aforementioned value, the output of the current setting DAC is increased by a preset value; if it is higher, it is decreased by a preset value. This operation is repeated to control the current of LED1-10 so that it remains within the set range. If upper or lower limits are set for the gate voltage applied to MOS1 or the output voltage of the current setting DAC, those conditions will also be followed. Furthermore, the pulsating voltage value In1, which occurs when the voltage value across resistor RD, generated by the current value ID of MOS1, settles within the set range, and the DAC instruction value at that time, are reflected in the reference voltage value, etc., as actual data from when LED1 to LED10 were driven. Then, this operation continues as long as the measured pulsating voltage In1 is equal to or greater than the preset illumination voltage (reference voltage 10) for LEDs 1 to 10, and returns to the previous operation when the reference voltage falls below 10.

[0044] As is clear from the above explanation, conventional LED lighting methods that do not use the technology of the present invention fix the power supply point of the LEDs and increase or decrease the number of lit LEDs according to the instantaneous voltage of the pulsating current. Therefore, the LEDs that light up when the instantaneous voltage is low remain lit even when the AC voltage drops, but the LEDs that light up when the instantaneous voltage is high gradually have shorter lighting times when the AC voltage drops and eventually turn off, and this turn off is even visible. In other words, with conventional AC drive, all LED rows light up when the AC voltage is at the lower limit of the fluctuation range, so the current that flows and its peak value are also at the lower limit of the AC voltage and do not flow any higher, and the current waveform plateaus. Therefore, when the AC voltage drops, it appears as if only some LEDs are off. This phenomenon is very likely to be perceived as if a failure has occurred in some of the LEDs and some LEDs have not lit up, so in order to avoid this, it was necessary to take care to ensure that all LEDs light up even at the lower limit of the AC voltage fluctuation range so that all LEDs light up when the AC voltage drops. Therefore, as a consequence, the fluctuations in the AC voltage could not be used to light the LEDs, leading to problems such as decreased efficiency in using AC input energy and increased losses.

[0045] However, according to the new AC driving method of the present invention, the lighting region of the LED array is dynamically changed in response to the instantaneous voltage of the pulsating current. This allows the LEDs, which conventionally only lit up when the instantaneous voltage was high, to light up even when the instantaneous voltage was low, enabling all LEDs to light up within the same pulsating current cycle even if the AD voltage fluctuates within a predetermined range. In other words, with the new AC driving method of the present invention, there is no waveform peaking up to the instantaneous voltage determined when all LEDs are lit, and it is possible to make the current waveform approximate the input voltage waveform. Furthermore, it is possible to approximate the current waveform to a sinusoidal wave even during voltage fluctuations, thus enabling further harmonic reduction. That is, by using the new AC driving method of this invention, even the AC voltage fluctuations that could not be used conventionally are made to contribute to LED lighting, resulting in a significant improvement in efficiency and a reduction in losses compared to conventional methods.

[0046] Next, a second embodiment of the details of the new AC drive method according to the present invention will be described. The second embodiment describes the case in which the new AC drive method according to the present invention is implemented using mixed analog and digital control. Figure 4 is a diagram that shows the contents of the control unit of the new AC drive method according to this second embodiment in more detail than Figure 1. In order to simplify the explanation and the diagrams, as before, the number of LEDs shown in the diagrams is fewer than the actual number of LEDs, and 10 LEDs are used as an example for the explanation. The details of this control system are explained below.

[0047] The second embodiment consists of constant current sources I1 to I6, switches OP1 to OP6 that control their operation, switches PSW01 and PSW02 for controlling the power supply points of the LEDs, resistors Ri1 to Ri6 for detecting the current flowing through each constant current source, and a constant current source control unit and LEDs that control these. The constant current source control unit has the following functions.

[0048] The constant current control unit controls the constant current sources I1 to I6 using switches OP1 to OP6, and also controls the power supply points according to the instantaneous voltage of the pulsating current using switches PSW01 and PSW02. The constant current control unit also recognizes whether each constant current source is operating or not by detecting the voltage across the resistors Ri1 to Ri6 connected to each constant current source I1 to I6.

[0049] Furthermore, although Figure 4 used to describe this second embodiment uses the switch PSW02, it should be noted that the purpose of PSW02 is to isolate LEDs 6 and 7 when PSW01 is closed and to prevent reverse voltage from being applied to LED 6. Therefore, if the forward voltage drop of the diode is within an acceptable range, PSW02 can be replaced with a diode.

[0050] Furthermore, this diagram illustrates an example where a switch is used to suppress the operation of a constant current source. The suppression of constant current source operation can be achieved by incorporating the suppression function within the constant current source itself, or by providing a separate switch function. However, the inventors of this invention believe that it is easier to understand by separating the constant current source and the switch and explaining them as individual operations. Therefore, the aforementioned functions are explained separately.

[0051] Next, a new AC drive method for the mixed analog-digital control system according to the second embodiment of the present invention described above will be explained. Specifically, the LED lighting control is started using the following procedure. (Operation 1) Immediately after power-on, the constant current source control unit closes switch PSW01 and switches OP01~03 to enable the operation of constant current sources I1~I3, while PSW02 and switches OP04~06 are opened, suppressing the operation of constant current sources I4~6. In reality, the start of operation rarely occurs at the rise of the pulsating current. Rather, it is more common for the system to sequentially perform operations in order of the operation number corresponding to the instantaneous voltage of the input pulsating current, while simultaneously controlling the lighting of the LEDs. However, explaining the operation in this way would be very complicated, so here we will explain the control by assuming that the constant current control unit starts operating the moment the pulsating current voltage begins to rise. (Operation 2) While the instantaneous voltage of the pulsating current is low and LEDs 7-8 do not light up, the constant current control unit closes switches OP1-3, while the other switches (OP4-6 are open, PSW01 is closed, and PSW02 is open) remain in their current state. The instantaneous voltage of the pulsating current gradually increases, and when the constant current source I1 starts operating, LEDs 7 and 8 light up, but constant current sources I2 and I3 remain in an operational state. The constant current control unit knows that the constant current source I1 has started operating when a voltage of I1 × Ri1 is generated across resistor Ri1. Similarly, the constant current control unit knows that I2 to I6 have started operating. This operation continues as long as the instantaneous voltage of the pulsating current does not rise further but the constant current source I2 has not yet started operating and LEDs 7-10 have not yet lit up. Once the constant current source I2 starts operating, the operation moves on to the next step. If constant current source I2 is not operating, and the current of constant current source I1 decreases or stops operating, it is determined that the instantaneous voltage of the pulsating current has decreased, and the current state is maintained until the pulsating current voltage rises again and LED lighting control becomes possible. (Operation 3) When the instantaneous voltage of the pulsating current rises, the constant current source I2 starts operating and LEDs 7-10 light up. The constant current control unit detects that constant current source I2 is operating and opens switch OP1 to suppress the operation of constant current source I1. However, constant current source I3 remains operational. The other switches remain in their current state (OP2-3 are closed, I2 is active, I3 can be operated, OP4-6 are open, operation of constant current sources I4-I6 is suppressed, PSW01 is closed, and PSW02 is open). If the instantaneous voltage of the pulsating current rises further but the constant current source I3 has not yet started operating and LEDs 1-6 have not yet lit up, this operation will continue. Once the constant current source I3 starts operating, the next operation will begin. If constant current source I3 does not operate and the current of constant current source I2 decreases or stops operating, it is determined that the instantaneous voltage of the pulsating current has decreased, and the switches are returned to their state before the start of this operation, and then the system returns to the previous step. (Operation 4) The instantaneous voltage of the pulsating current rises, the constant current source I3 starts operating, and LEDs 1-6 light up. The constant current control unit, upon detecting that constant current source I3 is operating, opens switch OP2 to suppress the operation of constant current source I2, then opens switch PSW01, closes PSW02, and closes switches OP4-OP6 to enable the operation of constant current sources I4-OP6. The other switches remain in their current state (OP1 is open, suppressing the operation of constant current source I1). If the instantaneous voltage of the pulsating current rises further but the constant current source I4 has not yet started operating and LEDs 1-8 have not yet lit up, this operation will continue, and once the constant current source I4 starts operating, the next operation will begin. If constant current source I4 fails to activate, and the current of constant current source I3 decreases or stops activating, it is determined that the instantaneous voltage of the pulsating current has decreased. The switches are then returned to their state before the start of this operation, and the system returns to the previous step. (Operation 5) The instantaneous voltage of the pulsating current rises, the constant current source I4 starts operating, and LEDs 1-8 light up. The constant current control unit, upon detecting that constant current source I4 has started operating, opens switch OP3 to suppress the operation of constant current source I3. However, constant current sources I5 and I6 remain operational. The other switches remain in their current state (OP1-2 are open, stopping constant current sources I1-I2; OP5-6 are closed, PSW01 is open, and PSW02 is closed). This operation continues as long as the instantaneous voltage of the pulsating current rises further but the constant current source I5 has not yet started operating and LEDs 1-9 have not yet lit up. When the constant current source I5 starts operating, the operation moves to the next step. If constant current source I5 fails to activate, and the current of constant current source I4 decreases or stops activating, it is determined that the instantaneous voltage of the pulsating current has decreased. The switches are then returned to their state before the start of this operation, and the system returns to the previous step. (Operation 6) The instantaneous voltage of the pulsating current rises, the constant current source I5 starts operating, and LEDs 1-9 light up. The constant current control unit detects that constant current source I5 has started operating and opens switch OP4 to suppress the operation of constant current source I4. However, constant current source I6 remains operational. The other switches remain in their current state (OP1-3 are open, stopping constant current sources I1-I3; OP5-6 are closed, PSW01 is open, and PSW02 is closed). This operation continues as long as the instantaneous voltage of the pulsating current rises further but the constant current source I6 has not yet started operating and LEDs 1-10 have not yet lit up. When the constant current source I6 starts operating, the operation moves to the next step. If constant current source I6 fails to activate, and the current of constant current source I5 decreases or stops activating, it is determined that the instantaneous voltage of the pulsating current has decreased. The switches are then returned to their state before the start of this operation, and the system returns to the previous step. (Operation 7) The instantaneous voltage of the pulsating current rises, the constant current source I6 starts operating, and LEDs 1-10 light up. The constant current control unit detects that the constant current source I6 has started operating and opens switch OP5 to suppress the operation of the constant current source I5. The other switches remain in their current state (OP1-5 are open, stopping constant current sources I1-I5; OP6 is closed, PSW01 is open, and PSW02 is closed). This operation continues as long as the instantaneous voltage of the pulsating current rises further but the constant current source I6 has not yet started operating and LEDs 1-10 have not yet lit up. When the constant current source I6 starts operating, the operation moves to the next step. This operation continues as long as the instantaneous voltage of the pulsating current is high and the constant current source I6 is operating. When the current of the constant current source I6 decreases or stops operating, it is determined that the instantaneous voltage of the pulsating current has decreased, and the switches are returned to their state before the start of this operation, and then the system returns to the previous step. From the specific descriptions of the various embodiments illustrated above, it is easy to understand that the contents of (1) to (5) below are sufficiently explained as the excellent technical concept of the present invention. (1) The LED lighting control method according to the present invention is an LED lighting control method that is driven by a full-wave rectified pulsating current and has an LED lighting control function that lights up an LED row in which a plurality of LEDs are connected in series between the power supply end on the near end and the far end, the power supply end on the near end has a first power supply point and a second power supply point is provided at a connection point between LEDs in which the number of LEDs connected in series from the near end is equal to or greater than the number of LEDs connected in series from the far end, and while the instantaneous voltage of the pulsating current is low, a first LED lighting control operation is performed in which the LEDs connected from the second power supply point toward the far end are lit up in accordance with the magnitude of the instantaneous value, and the second of After all LEDs from the power supply point to the furthest LED have been lit, a second LED lighting control operation is performed to light up more LEDs than the number of LEDs lit in the first LED lighting control operation, from the first power supply point on the near end to the furthest LED, according to the instantaneous value of the pulsating current. Following the second LED lighting control operation, the first and second lighting control operations are performed in reverse order as the instantaneous value of the pulsating current decreases from the peak value of the pulsating current voltage. (2) Preferably, of the LEDs connected in series, at least one LED is not composed of a single LED but rather of multiple LEDs connected in parallel. (3) Preferably, an on / off switch for isolation is provided between the second power supply point and the LED closest to it, and the on / off switch is opened during the first lighting control operation and closed during the second lighting control operation. (4) Alternatively, instead of providing the switch, a diode that performs an equivalent function to the switch may be provided. (5) A lighting device having the constituent requirements of (1) to (4) as described above can exhibit remarkable effects not seen in conventional lighting devices. Specifically, it can fully enjoy the advantages of the LED driving method, which uses full-wave rectification of the AC power supply to create a pulsating current and provides it directly to the LED without smoothing. In other words, the inventors of this invention would like to emphasize that this invention has the distinctive advantage of being able to utilize the energy of the AC power supply to the maximum extent without waste without using a large-capacity capacitor.

[0052] It should be noted that the circuit block diagrams and voltage / current (power) characteristic diagrams shown in the above-described embodiments and their modifications are merely examples, and it goes without saying that the structure, materials, circuit configuration, etc., can be appropriately modified within the scope that allows the effects of the present invention to be realized. Industrial application fields

[0053] The industrial application field of this invention relates to a control method for LED lighting that utilizes pulsating current obtained by full-wave rectification of alternating current in order to light an LED without using a DC power supply, and to any lighting device using this method.

Claims

1. This LED lighting method uses the pulsating current obtained by full-wave rectifying an AC voltage directly to light the LEDs, and includes an LED lighting control function that lights up an LED array configured by connecting multiple LEDs in series between the power supply end (near end) and the furthest end (farthest end). The device has a first power supply point on the near end, and a second power supply point at a connection point between LEDs where the number of LEDs connected in series from the near end is equal to or greater than the number of LEDs connected in series from the far end. When power is supplied from either the first power supply point or the second power supply point, a current switch is provided at a predetermined location between the LEDs connected from upstream to downstream that constitute the LED row, which measures the pulsating voltage at the time of power supply and lights up a number of LEDs corresponding to that pulsating voltage, and the opening and closing of these current switches is controlled. By appropriately switching a predetermined current switch according to the degree of instantaneous voltage rise during the rising phase of the pulsating voltage, the number of lit LEDs is increased from the LED closest to the second power supply point downstream toward the downstream side. As the instantaneous voltage rises further, all the LEDs in the LED row, from the LED closest to the second power supply point to the furthest downstream LED, are lit. When the instantaneous voltage rises further to a level sufficient to light up all the LEDs sandwiched between the first and second power supply points, power is supplied from the first power supply point instead of the second power supply point, and the current switch is flipped, thereby lighting up all the LEDs sandwiched between the first and second power supply points. As the instantaneous voltage rises further, the current switch is switched so that the number of lit LEDs increases from the LED closest to the second power supply point downstream toward the far end of the LED row, corresponding to the further voltage increase. When the instantaneous voltage reaches the peak voltage of the pulsating voltage and then begins to decrease, the current switch is toggled appropriately to light up LEDs corresponding to the decreasing instantaneous voltage, starting from the LEDs that were lit by the peak voltage. An LED lighting control method characterized in that, when the instantaneous voltage falls below the instantaneous voltage at which all LEDs between the first and second power supply points can light up, power is supplied from the second power supply point instead of the first power supply point, and the current switch is appropriately switched in accordance with the subsequent decrease in instantaneous voltage to reduce the number of LEDs that can light up from the furthest LED at the downstream end of the second power supply point toward the closest LED, thereby controlling the lighting of each LED so that all LEDs in the LED row are lit at least once within the same pulsating current waveform, regardless of whether the voltage is rising or falling within the fluctuation range of the AC power supply.

2. The LED lighting control method according to claim 1, characterized in that at least one of the LEDs connected in series is not composed of a single LED but is composed of multiple LEDs connected in parallel.

3. The LED lighting control method according to claim 1, characterized in that an on / off switch for isolation is provided between the second power supply point and the LED closest to it, and the on / off switch is opened during the first lighting control operation and closed during the second lighting control operation.

4. The LED lighting control method according to claim 3, characterized in that instead of having the aforementioned on / off switch, it is provided with a diode that performs an equivalent function to the on / off switch.

5. A lighting device comprising a control method according to any one of claims 1 to 4.

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