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

Abstract

The invention provides an LED lighting system, a power supply device, a lighting start processing method and a load device, which can simultaneously light the light sources of a plurality of LED lighting devices with different lighting voltages. The LED lighting system is provided with a plurality of LED light sources (30) with different lighting voltages and a plurality of power supply devices (20) which respectively output driving currents to the plurality of LED light sources, the output sides of the plurality of power supply devices are respectively provided with smoothing capacitors (25) which are connected in parallel with the LED light sources, and the power supply devices are provided with DC-DC converters (24) which are connected in parallel with the LED light sources. The driving circuit outputs driving current to the LED light source; and a control device (26) that controls the DC-DC converters such that, when a power source is supplied to the power source device or a lighting signal is input from the outside, the control device controls the corresponding DC-DC converter so as to output a current necessary to charge the smoothing capacitor to a lighting voltage of the corresponding LED light source for a predetermined time.

Description

Technical Field

[0001] The present invention relates to an LED lighting system, an LED lighting power supply device for lighting an LED (light emitting diode), and a lighting start processing method, and more particularly to a technology for lighting a plurality of LED light sources with different lighting voltages simultaneously. In addition, the present invention relates to a power supply device and a load device technology that can be applied to drive a load. Background Art

[0002] Conventionally, there is provided a power supply device for LED lighting, which rectifies an AC voltage supplied from a commercial AC power supply and converts it into a DC voltage and applies it to an LED light source to light it. In this LED lighting power supply device, if the voltage supplied from the power supply changes, the light quantity changes, so a smoothing capacitor for suppressing the change (pulsation) of the output voltage is provided on the output side of the power supply device. The smoothing capacitor is connected in parallel with the LED light source, so after the AC power supply is turned on, the LED light source is not lit before the smoothing capacitor is charged to the lighting voltage of the LED light source.

[0003] Therefore, in a power supply device for LED lighting provided with a smoothing capacitor on the output side, the time from the time when the AC power supply is turned on to the time when the LED light source is lit (start-up time) is longer than that of a power supply device without a smoothing capacitor. Therefore, an invention related to a lighting device capable of shortening the time required from the time when the AC power supply is turned on to the time when the LED light source starts to light up has been proposed (Patent Document 1).

[0004] When a voltage higher than the forward voltage of the LED is applied, a current flows through the LED light source to emit light. On the other hand, among LED lighting devices, there are LED lighting devices that use LEDs with different forward voltages, and LED lighting devices that use light sources with different numbers of LEDs connected in series, i.e., different lighting voltages. Moreover, in a lighting system that uses a single switch or remote control to provide lighting signals to multiple LED lighting power supply devices, 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 varies for each power supply device when multiple LED lighting devices using such light sources with different lighting voltages are arranged in one space.

[0005] Specifically, in two LED lighting devices using light sources with different lighting voltages (for example, 150V and 50V), if a power supply device of the same structure is used in each LED lighting device, the smoothing capacitor connected in parallel with each LED light source is charged with the same output current, so Figure 6 As shown in (A), there is a deviation in the time until the lighting voltage is reached. Figure 6As shown in (B) and (C), the timing of outputting the current to each LED light source (LED1, LED2) is staggered. As a result, the lighting start timing of each LED light source is offset by the lighting device, which has the problem of not looking good.

[0006] Patent Document 1: Japanese Patent No. 7108927 Summary of the invention

[0007] The present invention is completed with focus on the above-mentioned problems, and its purpose is to provide an LED lighting system, a power supply device for lighting, and a lighting start processing method that can simultaneously light up the light sources of multiple LED lighting devices in a lighting system having multiple LED lighting devices with different lighting voltages of the LED light sources.

[0008] In addition, another object of the present invention is to provide a power supply device and a load device that can simultaneously activate a plurality of loads in a power supply that drives a plurality of loads.

[0009] In addition, the subject of the invention of Patent Document 1 is to shorten the time required from the power supply to the lighting start of the LED light source, and there is no description for the simultaneous lighting of multiple LED light sources, that is, the subject is different from the invention of the present application. In addition, the invention of Patent Document 1 is characterized in that the load current is reduced before the detected voltage across both ends reaches the lighting start voltage, while the invention of the present application is characterized in that the load current required to charge the voltage across both ends of the smoothing capacitor to the lighting voltage in a specified time is calculated and flows for each LED light source, so the means for solving the subject are also different.

[0010] In order to achieve the above-mentioned object, the LED lighting system of the present invention comprises: a plurality of LED light sources with different lighting voltages; and a plurality of power supply devices that output drive currents to the plurality of LED light sources respectively based on an input power supply, wherein smoothing capacitors connected in parallel with the LED light sources are respectively provided on the output sides of the plurality of power supply devices.

[0011] The power supply device includes: a DC-DC converter that outputs a driving current to the LED light source; and a control device that controls the DC-DC converter.

[0012] When power is supplied to the power supply device or a lighting signal is input from the outside, the control device controls the corresponding DC-DC converter to output a current required to charge the smoothing capacitor to a lighting voltage of the corresponding LED light source in a predetermined time.

[0013] According to the above-mentioned means, in a lighting system having multiple LED lighting devices with different lighting voltages of LED light sources, the DC-DC converter outputs the current required to charge the smoothing capacitor connected in parallel with each LED light source to the lighting voltage of the LED light source in a predetermined time, thereby enabling multiple LED light sources to be lit simultaneously.

[0014] According to the LED lighting power supply device of the present invention, in a lighting system including a plurality of LED lighting devices having LED light sources with different lighting voltages, it is possible to simultaneously light the light sources of the plurality of LED lighting devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a block diagram showing a schematic configuration of the entire LED lighting system using the LED lighting power supply device of the present invention.

[0016] Figure 2 This is a block diagram showing a configuration example of an LED lighting power supply device constituting the lighting system according to the embodiment.

[0017] Figure 3 This is a flowchart showing an example of the procedure of dimming control performed by a microcomputer constituting the LED lighting power supply device.

[0018] Figure 4 This is a flowchart showing an example of the procedure of the lighting start processing performed by the microcomputer constituting the LED lighting power supply device.

[0019] Figure 5 This is a timing chart showing changes in voltage and current when the LED light source of the LED lighting power supply device of the embodiment starts lighting.

[0020] Figure 6 This is a timing chart showing changes in voltage and current when lighting of an LED light source of a conventional LED lighting power supply device is started. DETAILED DESCRIPTION

[0021] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

[0022] Figure 1 The schematic configuration of the entire LED lighting system using the LED lighting power supply device (hereinafter referred to as LED power supply) of the present invention is shown.

[0023] like Figure 1 As shown, the LED lighting system of this embodiment includes a plurality of LED power supplies 20A to 20D that receive an AC voltage AC from a commercial AC power supply 10 , and is configured to be able to supply or cut off the AC voltage AC to the LED power supplies 20A to 20D via a common power switch 11 .

[0024] Each LED power supply 20A to 20D has a different number of LEDs connected in series, for example, and thus has LED light sources 30A to 30D with different lighting voltages connected as loads. The LED power supplies 20A to 20D have the same model, that is, the same structure, although Figure 1 Although not shown in the figure, 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.

[0025] Figure 1 The lighting voltage of the LED light source 30A in the LED lighting system shown 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. In addition, an LED lighting device is formed by an LED power supply 20 and an LED light source 30 connected thereto.

[0026] In addition, the capacitance value of the smoothing capacitor of each LED power supply 20A to 20D is generally set according to the size of each load so that the ripple of the output voltage becomes less than a predetermined value. In this embodiment, the smoothing capacitors of the LED power supplies 20A to 20D connected to loads with different lighting voltages have the same capacitance value, but they can also have different capacitance values.

[0027] In addition, Figure 1 , a lighting system having four LED power supplies 20A to 20D is shown, but the number of LED power supplies is not limited to four, and may be two, three, or five or more. In addition, the lighting voltages of the LED light sources 30A, 30B, 30C, etc. connected to all the LED power supplies 20A, 20B, 20C, etc. do not need to be different, and an LED power supply that uses an LED light source with the same lighting voltage as a load may also be included.

[0028] Figure 2 Specific configuration examples of the LED power supplies 20A to 20D are shown.

[0029] like Figure 2 As shown, the LED power supply 20 of this embodiment includes: a filter circuit 21 that cuts off the noise contained in the AC voltage AC from the commercial AC power supply 10; a rectifier circuit 22 that is composed of a diode bridge circuit that performs full-wave rectification on the AC and converts it into DC; a PFC (power factor improvement) circuit 23; a DC-DC converter (DC voltage conversion circuit) 24; and a smoothing capacitor 25 that is provided on the output side of the DC-DC converter 24. The DC-DC converter 24 is composed of a switching buck converter (switching regulator).

[0030] 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 another terminal of the rectifier circuit 22, and a PFC control circuit that turns on and off the switching transistor. Such a circuit is well known, so a detailed description is omitted. In addition, a structure in which the PFC circuit 23 is omitted is also possible.

[0031] 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 drive circuit 27 that receives a current control signal output from the microcomputer 26 to generate a drive signal for the DC-DC converter 24 .

[0032] In addition, a signal receiving circuit 28 and a sub-power supply circuit 29 are provided in the LED power supply 20. The signal receiving circuit 28 receives a signal from an external dimmer 31 or reads the state of the dimmer 31, and transmits a dimming signal to the microcomputer 26. The sub-power supply circuit 29 generates a power supply voltage for the microcomputer 26 to operate based on the output voltage of the PFC circuit 23.

[0033] In addition, resistors R1 and R2 are connected in series between the output terminal OUT of the LED power supply 20 connected to the LED light source 30 and the ground point, and the voltage obtained by dividing the output voltage Vout by the resistors R1 and R2 is input as the feedback voltage VFB to the microcomputer 26. The microcomputer 26 generates a current control signal for the DC-DC converter 24 based on the feedback voltage VFB and the dimming signal from the signal receiving circuit 28.

[0034] Although not particularly limited, the current control signal supplied from the microcomputer 26 to the drive circuit 27 is supplied as a PWM (pulse width modulation) signal. In addition, the microcomputer 26 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 lighting voltage (target voltage) of the corresponding LED power supply 20, and a predetermined charging time in advance. Therefore, the above-mentioned memory functions as an information holding unit.

[0035] In addition, in this embodiment, the sub-power supply circuit 29 is configured to generate the power supply voltage of the microcomputer 26 etc. based on the voltage boosted by the PFC circuit 23, but the sub-power supply circuit 29 can also generate the power supply voltage of the microcomputer 26 etc. based on the voltage converted by the rectifier circuit 22.

[0036] In addition, the memory storing information such as the capacitance value and lighting voltage of the smoothing capacitor 25 is not limited to the built-in memory of the microcomputer 26, and may be a non-volatile memory connected to the microcomputer chip. As the dimmer 31, a dial-type or button-type potentiometer or a remote controller (hereinafter referred to as a remote controller) and the like are considered.

[0037] Next, use Figure 3 as well as Figure 4 , an example of the steps of dimming control processing and lighting start processing of the LED light source 30 performed by the microcomputer 26 is described. Figure 3 The control in the flowchart shown is started when the power switch 11 is turned on to input the AC voltage and the power voltage of the microcomputer 26 increases.

[0038] like Figure 3 As shown, when the dimming control process starts, the microcomputer 26 first reads out the storage information related to the mode input by the remote controller before the power is turned off from the predetermined storage area of ​​the built-in memory (step S1). Then, it is determined whether the storage information of the read mode is the lighting mode (step S2).

[0039] If it is determined in step S2 that the stored information is not the lighting mode (No), the process proceeds to step S3 to set the lighting mode request inside the microcomputer. If it is determined in step S2 that the stored information is the lighting mode (Yes), the process proceeds to step S4 to set the lighting mode request.

[0040] After that, the process proceeds to step S5 to confirm the set request mode. If it is determined that the request mode is the extinguishing mode, the process proceeds to step S6 to determine whether the current state is lighting. Then, if it is determined that the LED is lighting (yes) in step S6, the process proceeds to step S7 to execute the extinguishing process of stopping the operation of the DC-DC converter 24 and extinguishing the LED light source 30. In addition, if it is determined that the current state is not lighting (no) in step S6, the process proceeds to step S11.

[0041] On the other hand, if it is determined in the above step S5 that the set request mode is the lighting mode, the process proceeds to step S8 to determine whether the current state is lighting. Then, if it is determined to be lighting (yes), the process proceeds to step S9 to perform a dimming control process for generating a current control signal for the DC-DC converter 24 based on the dimming signal from the signal receiving circuit 28. In addition, in step S8, if it is determined that the current state is not lighting (no), the process proceeds to step S10 to perform the lighting start process (described later) of starting the DC-DC converter 24 to light up the LED light source 30. Figure 4 ).

[0042] After that, the process proceeds to step S11 to confirm the dimming signal from the dimmer 15. In addition, in the process of step S11, the request mode is updated according to the dimming signal. Specifically, if a dimming signal specifying an arbitrary brightness is received from the dimmer 15 during the off state, the lighting mode request is set, and if a signal specifying off is received from the dimmer 15 during the lighting state, the off mode request is set.

[0043] Next, proceed to step S12 to confirm the AC input status. If the AC input continues (is turned on), return to step S5 and repeat the above process. If the AC input is cut off (disconnected), proceed to step S13 to store the current mode in the memory and end the process.

[0044] exist Figure 4 It is shown in Figure 3 The specific processing steps of the lighting start processing in step S10 of the flowchart are as follows.

[0045] During the lighting start process, Figure 4 As shown, first, the feedback voltage VFB is read in to calculate the current output voltage, i.e., the load voltage (step S21), and the difference ΔV between the target voltage (the 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 predetermined time is calculated (step S24).

[0046] In addition, if the capacitance value of the smoothing capacitor is set to Cap and the charging time is set to Tc, the difference ΔV between the target voltage calculated in step S22 and the current load voltage can be used to calculate the load current Ic in step S24 by the following formula Ic=(ΔV×Cap)÷Tc. In addition, if the target voltage is set to Vt and the current load voltage is set to Vc, ΔV=(Vt﹣Vc), so step S22 can also be omitted and the load current Ic can be calculated using the following formula Ic=(Vt﹣Vc)×Cap÷Tc.

[0047] When the load current Ic is calculated, the process proceeds to step S25, where a current control signal is generated and outputted 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.

[0048] On the other hand, in step S26, if it is determined that the target voltage has not been reached (No), the process proceeds to step S27 to determine whether the charging time has expired (step S27). If it is determined that the charging time has expired (Yes), the process ends. In addition, if it is determined that the charging time has not expired (No) in step S27, the process returns to step S26 and the above process is repeated.

[0049] As described above, in the LED lighting system using the LED power source 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 flows for each LED power source 20. Therefore, even if the lighting voltage varies depending on the LED light source, Figure 5 As shown in (A), the time until the lighting voltage is reached is also the same, so, as Figure 5 As shown in (B) and (C), current can be caused to start flowing through a plurality of LED light sources (LED1, LED2) at the same time, and the plurality of LED light sources can be lit together.

[0050] The invention completed by the inventors is specifically described above based on the embodiments, but the present invention is not limited to the above embodiments. For example, in the above embodiments, it is described that the DC-DC converter 24 is composed of a switching buck converter (switching regulator), but the DC-DC converter 24 is not limited to a buck converter, and can also be a boost or buck-boost converter, an isolation power supply such as a flyback power supply, a linear regulator, and other forms of power supplies.

[0051] In the above embodiment, the lighting voltage of the LED light source connected to the LED power source is stored in the memory provided in the microcomputer 26, but the lighting voltage may be set in a setting device such as a DIP switch, and the microcomputer 26 reads the set value. Here, the setting device functions as an information holding unit that holds information.

[0052] Furthermore, in the above-described embodiment, in each LED power supply device 20 , the DC-DC converter 24 is controlled by the corresponding microcomputer 26 . However, one microcomputer 26 may control two or more DC-DC converters 24 .

[0053] In addition, in the above-mentioned embodiment, the load of the power supply device is described as an LED light source, but it may also be an organic EL light source. In addition, the load may not be a light source, and may also include a plurality of DC-DC converters, which are used to control the output voltage of the plurality of DC-DC converters to reach a predetermined voltage within a predetermined time after the input power is supplied when the setting values ​​of the output voltages are different.

[0054] Explanation of symbols

[0055] 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…microcomputer, 27…drive 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 having different lighting voltages, a plurality of power supply devices for outputting drive currents to the plurality of LED light sources, respectively, and smoothing capacitors connected in parallel to the LED light sources are respectively provided on the output sides of the plurality of power supply devices, characterized in that: The power supply device includes: a DC-DC converter that outputs a driving current to the LED light source; and a control device that controls the DC-DC converter. When power is supplied to the power supply device or a lighting signal is input from the outside, the control device controls the corresponding DC-DC converter to output a current required to charge the smoothing capacitor to a lighting voltage of the corresponding LED light source in a predetermined time.

2. A lighting power supply device, comprising: a rectifying unit that rectifies an input AC voltage; A DC-DC converter that generates and outputs a driving current that flows in an LED light source connected to an output terminal based on the voltage rectified by the rectifying unit; and a control device that controls the DC-DC converter; and a smoothing capacitor connected to the output terminal for smoothing the output voltage of the DC-DC converter, characterized in that: When power is supplied or a lighting signal is input from the outside, the control device calculates a current value required to charge the smoothing capacitor to a lighting voltage of the LED light source in a predetermined time, and controls the DC-DC converter to output a current of the calculated current value.

3. The power supply device according to claim 2, characterized in that: The control device includes an information holding unit in which the capacitance value of the smoothing capacitor, the lighting voltage of the corresponding LED light source, and a predetermined charging time are stored or set. inputting a voltage proportional to the output voltage of the DC-DC converter into the control device, When input power is supplied to the power supply device or a lighting signal is input from the outside, the control device reads the capacitance value of the smoothing capacitor, the lighting voltage of the LED light source and the charging time from the information holding unit, and calculates the current value required to charge the smoothing capacitor to the lighting voltage using a predetermined calculation formula.

4. The power supply device according to claim 2 or 3, characterized in that: The control device includes a signal receiving unit for receiving a signal from an external dimmer, and generates a dimming control signal for controlling the DC-DC converter based on the signal from the dimmer, thereby changing the brightness by varying the current flowing from the DC-DC converter to the LED light source.

5. A lighting start processing method of a control device constituting a power supply device, the power supply device comprising: a DC-DC converter which generates and outputs a driving current flowing through an LED light source by being supplied with power; the control device which comprises an information holding unit and controls the DC-DC converter; and a smoothing capacitor which is provided at the output side of the DC-DC converter and connected in parallel with the LED light source, characterized in that: The lighting start processing method comprises the following steps: In the first step, when power is supplied or a lighting signal is input from the outside, a voltage proportional to the output voltage of the DC-DC converter is read to grasp the load voltage at the current time point; The second step is to read the capacitance value of the smoothing capacitor, the lighting voltage of the LED light source and the predetermined charging time from the information holding unit; A third step of calculating a current value required to charge the smoothing capacitor to the lighting voltage by a predetermined calculation formula based on the load voltage at the current time point grasped by the first step and the capacitance value, lighting voltage and charging time read out by the second step; and In a fourth step, a control signal is generated to control the DC-DC converter so as to output a current having the current value calculated in the third step, and the control signal is output to the DC-DC converter.

6. A power supply device for driving a load, the power supply device comprising: a rectifying unit that rectifies an input AC voltage; A DC-DC converter that generates and outputs a drive current that flows in a load connected to an output terminal based on the voltage rectified by the rectifying unit; and a control device that controls the DC-DC converter; and a smoothing capacitor connected to the output terminal for smoothing the output voltage of the DC-DC converter, characterized in that: When power is supplied or a start signal is input from the outside, the control device calculates a current value required to charge the smoothing capacitor to a predetermined output voltage in a predetermined time, and controls 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 that output drive currents to the plurality of loads based on an input power supply, wherein smoothing capacitors connected in parallel to the loads are provided on the output sides of the plurality of power supply devices, characterized in that: The power supply device includes: a DC-DC converter that outputs a drive current to the load; and a control device which controls the DC-DC converter, When power is supplied to the power supply device, the control device controls the corresponding DC-DC converters to output currents required to charge the smoothing capacitors to a predetermined voltage within a predetermined time.

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