LED lighting system, power supply device, lighting start processing method, and load device

Abstract

To enable simultaneous lighting of light sources of multiple LED lighting devices with different lighting voltages.SOLUTION: An LED lighting system includes multiple LED light sources (30) with different lighting voltages and multiple power supply devices (20) that each output a drive current to each of the multiple LED light sources. In the LED lighting system, a smoothing capacitor (25) connected in parallel with the LED light sources is provided on the output side of the multiple power supply devices, respectively. The power supply devices include DC-DC converters (24) that each output a drive current to each of the LED light sources and a control device (26) that controls the DC-DC converters. The control device is configured to control the corresponding DC-DC converter so as to output a current required to charge the smoothing capacitor to the lighting voltage of the corresponding LED light source in a predetermined time when the power supply device is supplied with power or a lighting signal is input from an external source.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an LED lighting system, a power supply device for LED lighting that lights up LEDs (light emitting diodes), and a lighting start processing method, and in particular to a technology for simultaneously lighting up multiple LED light sources with different lighting voltages.The present invention also relates to a power supply device that drives a load and a technology applicable to the load device. [Background technology]

[0002] Conventionally, power supply devices for LED lighting have been provided that rectify AC voltage supplied from a commercial AC power source, convert it to DC voltage, and apply it to an LED light source to light it up. In such power supply devices for LED lighting, a smoothing capacitor is provided on the output side of the power supply device to suppress output voltage fluctuations (ripples) since the amount of light fluctuates when the voltage supplied from the power source fluctuates. Since this smoothing capacitor is connected in parallel with the LED light source, the LED light source will not light up after the AC power source is turned on until the smoothing capacitor is charged to the lighting voltage of the LED light source.

[0003] Therefore, in a power supply device for LED lighting that has a smoothing capacitor on the output side, the time from when the AC power supply is turned on until the LED light source starts to light (start-up time) is longer than in a power supply device that does not have a smoothing capacitor. Therefore, an invention has been proposed relating to a lighting device that is able to shorten the time required from when the AC power supply is turned on until the LED light source starts to light up (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7108927 Summary of the Invention [Problem to be solved by the invention]

[0005] When a voltage equal to or greater than the forward voltage of the LED is applied to an LED light source, a current flows through it and the light is emitted. Meanwhile, some LED lighting devices use LEDs with different forward voltages, and some use light sources with different numbers of LEDs connected in series, i.e., different lighting voltages. In a lighting system in which multiple LED lighting devices using light sources with different lighting voltages are arranged in one space and a single switch or remote control is used to send a lighting signal to multiple LED lighting power supplies, the time it takes for the smoothing capacitor connected in parallel with the LED light source to reach the lighting voltage of the LED light source will differ for each power supply.

[0006] Specifically, when two LED lighting devices using light sources with different lighting voltages (for example, 150V and 50V) are used, and a power supply with the same configuration is used for each LED lighting device, the smoothing capacitors in parallel with each LED light source are charged with the same output current, so there is a difference in the time it takes to reach the lighting voltage, as shown in Figure 6 (A). Therefore, as shown in Figures 6 (B) and (C), there is a difference in the timing when the output current starts to flow to each LED light source (LED1, LED2). As a result, there is a problem that the timing at which each LED light source starts to light differs depending on the lighting device, which makes the appearance look bad.

[0007] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an LED lighting system, a power supply device for lighting, and a lighting start processing method that are capable of simultaneously lighting the light sources of a plurality of LED lighting devices having different lighting voltages for the LED light sources in the lighting system. Another object of the present invention is to provide a power supply device and a load device that can start a plurality of loads simultaneously in a power supply that drives the plurality of loads.

[0008] The invention in Patent Document 1 aims to shorten the time required from when the power is turned on until the LED light source starts to light up, and does not mention the simultaneous lighting of multiple LED light sources, which means that the problem is different from that of the invention in this application. Also, while the invention in Patent Document 1 is characterized by reducing the load current before the detected voltage between both ends reaches the lighting start voltage, the invention in this application is characterized by calculating and flowing the load current required to charge the voltage between both ends of the smoothing capacitor to the lighting voltage in a specified time for each LED light source, and the means for solving the problem are also different. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides An LED lighting system comprising a plurality of LED light sources each having a different lighting voltage, and a plurality of power supply devices each outputting a drive current to each of the plurality of LED light sources based on an input power source, the plurality of power supply devices each having a smoothing capacitor connected in parallel to the LED light source at the output side thereof, The power supply device includes a DC-DC converter that outputs a drive current to the LED light source, and a control device that controls the DC-DC converter, The control device is configured to control the corresponding DC-DC converter so as to output a current required to charge the smoothing capacitor to the lighting voltage of the corresponding LED light source within a predetermined time when power is supplied to the power supply device or a lighting signal is input from the outside.

[0010] According to the above-mentioned means, in a lighting system equipped with multiple LED lighting devices with different lighting voltages for the LED light sources, the DC-DC converter outputs a current required to charge the smoothing capacitor connected in parallel to each LED light source up to the lighting voltage of the LED light source in a specified time, so that the multiple LED light sources can be turned on simultaneously. Effect of the Invention

[0011] The LED lighting power supply device according to the present invention has the advantage that in a lighting system equipped with a plurality of LED lighting devices each having a different lighting voltage for its LED light source, the light sources of the plurality of LED lighting devices can be turned on simultaneously. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing a schematic configuration of an entire LED lighting system using a power supply device for LED lighting according to the present invention. [Diagram 2] 1 is a block diagram showing an example of the configuration of a power supply device for LED lighting that constitutes a lighting system according to an embodiment. [Diagram 3] 4 is a flowchart showing an example of a procedure for dimming control by a microcomputer constituting the power supply device for LED lighting. [Figure 4] 5 is a flowchart showing an example of a procedure for a lighting start process performed by a microcomputer constituting the LED lighting power supply device. [Diagram 5] 4 is a timing chart showing changes in voltage and current at the start of lighting an LED light source by the LED lighting power supply device of the embodiment. [Figure 6] 1 is a timing chart showing changes in voltage and current when an LED light source starts to be turned on by a conventional power supply device for LED lighting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an entire LED lighting system using a power supply device for LED lighting (hereinafter referred to as an LED power supply) according to the present invention. As shown in FIG. 1, the LED lighting system of this embodiment includes a plurality of LED power sources 20A-20D that receive an AC voltage AC from a commercial AC power source 10 as input, and a common power switch 11 is used to supply or cut off the AC voltage AC to the LED power sources 20A-20D.

[0014] The LED power sources 20A to 20D are connected as loads to the LED light sources 30A to 30D, which have different lighting voltages due to, for example, a different number of LEDs connected in series. The LED power sources 20A to 20D are of the same model, i.e., have the same configuration, and although not shown in FIG. 1, a smoothing capacitor is connected to the output side of each of the LED power sources 20A to 20D in parallel with the LED light sources 30A to 30D. 1, the lighting voltage of the LED light source 30A is equal to the forward voltage VF of the LED, the lighting voltage of the LED light source 30B is 2VF, the lighting voltage of the LED light source 30C is 3VF, and the lighting voltage of the LED light source 30D is 4VF. Note that one LED lighting device is composed of one LED power supply 20 and the LED light source 30 connected thereto.

[0015] In addition, the smoothing capacitors of the LED power sources 20A to 20D are generally set to have a capacitance value that is smaller than a predetermined value depending on the magnitude of each load, so that the ripple of the output voltage is kept below a predetermined value. In this embodiment, the smoothing capacitors of the LED power sources 20A to 20D connected to loads with different lighting voltages have the same capacitance value, but may have different capacitance values. 1 shows a lighting system equipped with four LED power supplies 20A to 20D, but the number of LED power supplies is not limited to four, and may be two, three, or five or more. Also, the lighting voltages of the LED light sources 30A, 30B, 30C, etc. connected to all of the LED power supplies 20A, 20B, 20C, etc. do not need to be different, and LED power supplies may include LED light sources with the same lighting voltage as a load.

[0016] FIG. 2 shows a specific configuration example of the LED power sources 20A to 20D. 2, the LED power supply 20 of this embodiment includes a filter circuit 21 that blocks noise contained in the AC voltage AC from the commercial AC power supply 10, a rectifier circuit 22 consisting of a diode bridge circuit or the like that performs full-wave rectification of the AC to convert it to DC, a PFC (power factor correction) circuit 23, a DC-DC converter (DC voltage conversion circuit) 24, and a smoothing capacitor 25 provided on the output side of the DC-DC converter 24. The DC-DC converter 24 is configured by a switching-type step-down converter (switching regulator).

[0017] The PFC circuit 23 can be composed of, for example, a boost inductor (choke coil) and a rectifier diode connected in series between one terminal of the rectifier circuit 22 and one terminal of the DC-DC converter 24, a switching transistor connected between a connection node of the inductor and the rectifier diode and the other terminal of the rectifier circuit 22, and a PFC control circuit that drives the switching transistor to turn on and off. Such circuits are well known, so a detailed description will be omitted. Note that a configuration without the PFC circuit 23 is also possible.

[0018] The LED power supply 20 also includes a microcontroller (hereinafter, referred to as a microcomputer) 26 that controls the output current of the DC-DC converter 24, and a driver circuit 27 that receives a current control signal output from the microcomputer 26 and generates a drive signal for the DC-DC converter 24. Furthermore, the LED power supply 20 is provided with a signal receiving circuit 28 that receives a signal from an external dimmer 31 or reads the state of the dimmer 31 and transmits a dimming signal to the microcontroller 26, and a sub-power supply circuit 29 that generates a power supply voltage for operating the microcontroller 26 and the like based on the output voltage of the PFC circuit 23.

[0019] Resistors R1 and R2 are connected in series between the output terminal OUT of the LED power supply 20 to which the LED light source 30 is connected and the ground point, and a voltage obtained by dividing the output voltage Vout by the resistors R1 and R2 is input as a feedback voltage VFB to the microcomputer 26. The microcomputer 26 generates a current control signal for the DC-DC converter 24 in response to the feedback voltage VFB and the dimming signal from the signal receiving circuit 28. Although not particularly limited, the current control signal supplied from the microcomputer 26 to the driver circuit 27 is supplied as a PWM (pass-width modulation) signal. The microcomputer 26 also has a built-in memory for electrically storing data, and the memory stores information such as the capacitance value of the smoothing capacitor 25, the corresponding lighting voltage (target voltage) of the LED power supply 20, and a predetermined charging time. Therefore, the memory functions as an information storage means.

[0020] In this embodiment, the sub-power supply circuit 29 is configured to generate a power supply voltage for the microcontroller 26, etc. based on the voltage boosted by the PFC circuit 23, but the sub-power supply circuit 29 may also be configured to generate a power supply voltage for the microcontroller 26, etc. based on the voltage converted by the rectifier circuit 22. Moreover, the memory for storing information such as the capacitance value of the smoothing capacitor 25 and the lighting voltage is not limited to the built-in memory of the microcomputer 26, but may be a non-volatile memory connected to the microcomputer chip. The dimmer 31 may be a dial or push button volume, a remote controller (hereinafter referred to as a remote control), or the like.

[0021] Next, an example of a procedure for dimming control processing and lighting start processing of the LED light source 30 by the microcomputer 26 will be described with reference to Figures 3 and 4. The control according to the flowchart shown in Figure 3 is started when the power switch 11 is turned on, AC voltage is input, and the power supply voltage of the microcomputer 26 starts up. 3, when the dimming control process is started, the microcomputer 26 first reads out stored information on the mode input by the remote control before the power was cut off from a predetermined storage area of ​​the built-in memory (step S1). Then, the microcomputer 26 determines whether the stored information on the read out mode is the lighting mode or not (step S2).

[0022] If it is determined in step S2 that the stored information is not the on mode (NO), the process proceeds to step S3, where a request for the off mode is set in the microcomputer, whereas if it is determined in step S2 that the stored information is the on mode (YES), the process proceeds to step S4, where a request for the on mode is set. Thereafter, the process proceeds to step S5, where the set requested mode is confirmed. If it is determined that the requested mode is the off mode, the process proceeds to step S6, where it is determined whether the current state is on or not. If it is determined in step S6 that the light is on (YES), the process proceeds to step S7, where a light-off process is executed to stop the operation of the DC-DC converter 24 and turn off the LED light source 30. If it is determined in step S6 that the current state is not on (NO), the process proceeds to step S11.

[0023] On the other hand, if it is determined in step S5 that the requested mode is the lighting mode, the process proceeds to step S8, where it is determined whether the current state is lighting. If it is determined that the light is on (YES), the process proceeds to step S9, where a dimming control process is performed to generate a current control signal for the DC-DC converter 24 in response to the dimming signal from the signal receiving circuit 28. If it is determined in step S8 that the light is not on (NO), the process proceeds to step S10, where a lighting start process (FIG. 4) is performed, which will be described later, to start up the DC-DC converter 24 and light the LED light source 30.

[0024] Then, the process proceeds to step S11, where a process is performed to confirm a dimming signal from the dimmer 15. In addition, in the process of step S11, the requested mode is updated according to the dimming signal. Specifically, when a dimming signal specifying an arbitrary brightness is received from the dimmer 15 while the light is off, a request for the on mode is set, and when a signal specifying off is received from the dimmer 15 while the light is on, a request for the off mode is set. Next, proceed to step S12, check the AC input status, and if the AC input continues (ON), return to step S5 and repeat the above process; if the AC input is interrupted (OFF), proceed to step S13, store the current mode in memory, and end the process.

[0025] FIG. 4 shows a specific procedure for the lighting start process in step S10 of the flowchart in FIG. 4, in the lighting start process, the feedback voltage VFB is first read to calculate the current output voltage, i.e., the load voltage (step S21), and the difference ΔV between the target voltage (lighting voltage of the LED light source) and the current load voltage is calculated (step S22). Next, the capacitance value of the smoothing capacitor, the lighting voltage (target voltage), and the charging time are read from the built-in memory (step S23), and the load current Ic required to charge the smoothing capacitor to the lighting voltage in a specified time is calculated (step S24).

[0026] The load current Ic in step S24 is calculated by the following equation using the difference ΔV between the target voltage calculated in step S22 and the current load voltage, where Cap is the capacitance of the smoothing capacitor and Tc is the charging time. Ic = (ΔV × Cap) ÷ Tc In addition, if the target voltage is Vt and the current load voltage is Vc, ΔV=(Vt-Vc), so step S22 can be omitted and the following formula can be used: Ic = (Vt-Vc) × Cap ÷ Tc The load current Ic may be calculated using the following equation:

[0027] Once the load current Ic has been calculated, the process proceeds to step S25, where a current control signal is generated and output so that the load current Ic calculated in step S24 flows through the DC-DC converter 24. Thereafter, it is determined whether the current load voltage has reached the target voltage (step S26), and if it is determined that the target voltage has been reached (YES), the process ends. On the other hand, if it is determined in step S26 that the target voltage has not been reached (NO), the process proceeds to step S27 to determine whether the charging time has elapsed (step S27), and if it is determined that the charging time has elapsed (YES), the process ends. If it is determined in step S27 that the charging time has not elapsed (NO), the process returns to step S26 and the above process is repeated.

[0028] As described above, in the LED lighting system using the LED power supply 20 of the above embodiment, the load current Ic required to charge the smoothing capacitor 25 connected in parallel with the LED light source 30 to the lighting voltage in a predetermined time is calculated and supplied for each LED power supply 20. Therefore, even if the lighting voltage differs depending on the LED light source, the time required to reach the lighting voltage is the same as shown in Figure 5 (A), and therefore, as shown in Figures 5 (B) and (C), it is possible to start flowing current to multiple LED light sources (LED1, LED2) at the same time, and it becomes possible to light up multiple LED light sources simultaneously.

[0029] Although the invention made by the present inventor has been specifically described above based on the embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiments, it has been described that the DC-DC converter 24 is configured by a switching-type step-down converter (switching regulator), but the DC-DC converter 24 is not limited to a step-down converter, and may be a step-up or step-up / step-down converter, an isolated power supply such as a flyback power supply, a linear regulator, or other types of power supplies.

[0030] In the above embodiment, the lighting voltage of the LED light source connected to the LED power supply is stored in the memory of the microcomputer 26, but the lighting voltage may be set in a setting device such as a DIP switch, and the microcomputer 26 may read the set value. Here, the setting device functions as information storage means for storing information. Furthermore, in the above embodiment, in each LED power supply device 20, the DC-DC converter 24 is configured to be controlled by a corresponding microcomputer 26, but two or more DC-DC converters 24 may be configured to be controlled by a single microcomputer 26.

[0031] In the above embodiment, the load of the power supply device is described as an LED light source, but it may be an organic EL light source. The load does not have to be a light source, and may be provided with multiple DC-DC converters, and when the output voltage settings of the multiple DC-DC converters are different, the load may be used to control the output voltage to reach a predetermined voltage in a predetermined time after the input power is supplied. [Explanation of symbols]

[0032] 10...AC power supply, 11...common power switch, 20...LED power supply device, 21...filter circuit, 22...rectifier circuit, 23...PFC circuit, 24...DC-DC converter, 25...smoothing capacitor, 26...microcontroller, 27...driver circuit, 28...signal receiving circuit, 29...sub-power supply circuit, 30...LED light source, 31...dimmer

Claims

1. An LED lighting system comprising: a plurality of LED light sources each having a different lighting voltage; and a plurality of power supply devices each outputting a drive current to each of the plurality of LED light sources, the plurality of power supply devices each having a smoothing capacitor connected in parallel to the LED light source at an output side thereof, The power supply device includes a DC-DC converter that outputs a drive current to the LED light source, and a control device that controls the DC-DC converter; The control device is configured to control the corresponding DC-DC converter so as to output a current required to charge the smoothing capacitor to the lighting voltage of the corresponding LED light source within a predetermined time when power is supplied to the power supply device or a lighting signal is input from the outside.

2. A power supply device for lighting, comprising: a rectifying means for rectifying an input AC voltage; a DC-DC converter for generating and outputting a drive current to be passed to an LED light source connected to an output terminal based on the voltage rectified by the rectifying means; a control device for controlling the DC-DC converter; and a smoothing capacitor connected to the output terminal for smoothing an output voltage of the DC-DC converter, The control device is configured to calculate a current value required to charge the smoothing capacitor to the lighting voltage of the LED light source in a specified time when power is supplied or a lighting signal is input from the outside, and to control the DC-DC converter to output a current of the calculated current value.

3. The control device includes an information storage means, and the information storage means stores or sets a capacitance value of the smoothing capacitor, a lighting voltage of the corresponding LED light source, and a predetermined charging time, A voltage proportional to the output voltage of the DC-DC converter is input to the control device, 3. The power supply device according to claim 2, wherein the control device is configured to, when an input power source is supplied to the power supply device or an external lighting signal is input, read out a capacitance value of the smoothing capacitor and a lighting voltage and charging time of the LED light source from the information holding means, and calculate a current value required to charge the smoothing capacitor to the lighting voltage using a predetermined formula.

4. The power supply device according to claim 2 or 3, characterized in that the control device is configured to include a signal receiving means for receiving a signal from an external dimmer, generate a dimming control signal for controlling the DC-DC converter based on the signal from the dimmer, and change the current flowing from the DC-DC converter to the LED light source to change the brightness.

5. A lighting start processing method by a control device constituting a power supply device including a DC-DC converter that generates and outputs a drive current to be passed through an LED light source when power is supplied, a control device having an information holding means and controlling the DC-DC converter, and a smoothing capacitor that is provided on the output side of the DC-DC converter and connected in parallel with the LED light source, comprising: A first step of reading a voltage proportional to an output voltage of the DC-DC converter when power is supplied or a lighting signal is input from an external source to grasp a current load voltage; a second step of reading out the capacitance value of the smoothing capacitor, the lighting voltage of the LED light source, and a predetermined charging time from the information holding means; a third step of calculating a current value required to charge the smoothing capacitor to the lighting voltage by a predetermined formula based on the current load voltage grasped in the first step and the capacitance value, lighting voltage, and charging time read out in the second step; and a fourth step of generating a control signal for controlling the DC-DC converter so as to output a current of the current value calculated in the third step, and outputting the control signal to the DC-DC converter.

6. A power supply device for driving a load, comprising: a rectifying means for rectifying an input AC voltage; a DC-DC converter for generating and outputting a drive current to be passed to a load connected to an output terminal based on the voltage rectified by the rectifying means; a control device for controlling the DC-DC converter; and a smoothing capacitor connected to the output terminal for smoothing an output voltage of the DC-DC converter, The control device is configured to calculate a current value required to charge the smoothing capacitor to a predetermined output voltage in a predetermined time when power is supplied or an external startup signal is input, and to control the DC-DC converter to output a current of the calculated current value.

7. A load device comprising: a plurality of loads; and a plurality of power supply devices each outputting a drive current to each of the plurality of loads based on an input power source, the plurality of power supply devices each having a smoothing capacitor connected in parallel to the load at an output side thereof, The power supply device includes a DC-DC converter that outputs a drive current to the load, and a control device that controls the DC-DC converter, The control device is configured to control each of the corresponding DC-DC converters so as to output a current required to charge the smoothing capacitor to a predetermined voltage in a predetermined time when power is supplied to the power supply device.

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