LED control device and lighting device comprising the same

Abstract

Including a light-emitting diode (LED) control device: a power supply (110; 210; 410; 510; 631; 731; 831) connected to a first control node (21; 101; 201; 401; 501; 601; 716; 816) and a second control node (22; 102; 202; 402; 502; 602; 717; 817) of an LED driver (20; 300; 620; 710; 810) configured to provide a control power to a light source (30; 105; 205; 405; 505; 610; 720; 820) having a plurality of LEDs; a controller (120; 220; 420; 520; 632; 732; 832) that is set up by a first internal power voltage (V INT1 ) to be operated, which is output by the power supply (110; 210; 410; 510; 631; 731; 831), and to receive a control command from an external controller (240); and a switching device (130; 130A; 230; 430; 530; 530A; 530B; 633; ​​733; 833) which is connected to the second control node (22; 102; 202; 402; 502; 602; 717; 817) and which is configured by a second internal power voltage (V INT2 ) to be operated, which is output by the power supply (110; 210; 410; 510; 631; 731; 831), and based on a control signal output from the controller (120; 220; 420; 520; 632; 732; 832), responding to the control command to control the brightness of the light source (30; 105; 205; 405; 505; 610; 720; 820), wherein the switching device (130A; 530; 530A; 530B) comprises a first switch (SW1) and a second switch (SW2) connected in parallel between the second control node (102) and the light source (105), wherein when the first switch (SW1) is switched on, the second switch (SW2) is switched off, and when the second switch (SW2) is switched on, the first switch (SW1) is switched off, and wherein the switching device (530A; 530B) has a leakage resistor (536) which is connected between the second switch (SW2) and the second control node (502) or between the second switch (SW2) and the light source (505).

Description

BACKGROUND

[0001] Embodiments of the present disclosure relate to an LED control device and a lighting device comprising the same.

[0002] Light-emitting diodes (LEDs) offer low power consumption and long lifespans, and have rapidly replaced conventional fluorescent tubes and incandescent lamps. Recently, various types of lighting devices using LEDs as light sources have been developed and marketed, and active research is being conducted on lighting devices that incorporate various functions in addition to simple illumination. For example, a lighting device might include a function for controlling the color temperature and / or brightness of a light, or for monitoring the operating status of LEDs mounted as light sources.

[0003] US 2019 / 0306949A1 relates to a control device and system for controlling the output power of a constant current driver, which is arranged between the driver and the load to enable additional functions such as dimming via the 0-10V input, color mixing by switching elements, buffer load for turn-on behavior, and dim-to-when operation.

[0004] The subsequently published DE 10 2021 130 316 A1 relates to an LED device with two parallel connected LED strings of different color temperatures, the brightness of which is controlled individually or in combination via a controller and a circuit, wherein an internal power supply enables the operation of the control units.

[0005] DE 10 2015 211 454 A1 relates to a sensor with input connections for connection to a control gear for light sources, output connections for connection to the light source and a circuit for power supply which generates a supply voltage for the sensor from the constant current generated by the control gear.

[0006] US 2019 / 0234567A1 relates to an LED module with several parallel-connected LED strings of different color temperatures and a module controller that detects the input voltage, adjusts the ratio of the currents supplied to the strings to set the color temperature, and thereby reduces brightness fluctuations independent of the color temperature.

[0007] US 2011 / 0235328A1 relates to an LED light fixture with at least one LED and at least one thermoelectric generator that extracts energy from heat emitted by the LED, and an energy management module that absorbs the energy extracted by the thermoelectric generator.

[0008] US 2018 / 0159354A1 concerns an electronic device for Li-Fi communication with at least one LED for transmitting Li-Fi signals and an energy recovery device that extracts electrical energy from the heat generated by the LED to power the device.

[0009] DE 10 2018 127 452 B3 relates to a method for operating a phase-controlled or phase-cut dimmer-light source combination connected to a power supply network, in which harmonic components of the load current are detected and the control of the light source is adjusted if a limit value is exceeded, as well as a dimmer with measuring logic for determining and reducing such harmonics. SUMMARY

[0010] The object of the present invention is to provide an LED control device that can reduce the replacement and / or upgrade rate of components included in a lighting device and that can implement various functions, as well as the lighting device that includes this.

[0011] This task is solved by the subject matter of the independent claims. Advantageous designs and further developments are the subject matter of the dependent claims.

[0012] According to one embodiment, an LED control device is provided which may include: a power supply connected to a first drive node and a second drive node of an LED driver configured to provide drive power to a light source comprising a plurality of LEDs; a controller configured to be operated by a first internal power voltage output by the power supply and to receive a control command from an external controller; and a switching device connected to the second drive node and configured to be operated by a second internal power voltage output by the power supply and to control the brightness of the light source based on a control signal output from the controller, responding to the control command.

[0013] According to one embodiment, a lighting device is created which may include: an LED driver configured to generate a drive power for driving LEDs using alternating current power, and to output the drive power through a first drive node and a second drive node; a light source comprising at least one LED string having the LEDs and connected between the first drive node and at least one LED node;and an LED control device connected between the LED driver and the light source with the first control node, the second control node and the LED node, wherein the LED control device comprises a controller connected for communication with an external controller, a switching device connected between the LED node and the second control node and configured to control the LED string in response to a control signal output by the controller, and a power supply connected to the first control node and the second control node and configured to output an internal power voltage for operation of the controller and the switching device.

[0014] According to one embodiment, an LED control device is provided which may include: a power supply connected to a first output terminal and a second output terminal from a plurality of output terminals included in an output wiring harness of an LED driver, and configured to generate a first internal power voltage and a second internal power voltage using drive power supplied by the LED driver; a controller configured to be driven by the first internal power voltage and to generate a pulse-width modulation (PWM) signal as a control signal based on a control command received from an external controller;and a switching device connected to the second output terminal, which is configured to be operated by the second internal power voltage and to adjust the brightness of at least one of a plurality of LEDs operated by the drive power, based on the control signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Several aspects, features and advantages of the present disclosure will become clearer from the following detailed description in conjunction with the accompanying drawings, in which: Fig. 1 is a block diagram representing a lighting device according to one embodiment; Fig. 2 is a block diagram representing an LED control device and a light source according to one embodiment; Fig. 3 and Fig. Four circuit diagrams are shown, depicting a switch and a light source with reference to... Fig. 1 and Fig. 2 according to embodiments; Fig. 5 is a block diagram representing an LED control device and a light source according to one embodiment; Fig. 6 is a block diagram representing an LED driver according to one embodiment; Fig. 7 is a circuit diagram that represents a converter circuit included in an LED driver according to one embodiment; Fig. Figure 8 shows graphs relating to a dimming function of an LED control device, according to one embodiment; Fig. 9 is a block diagram representing an LED control device and a light source according to one embodiment; Fig. 10 to 12 graphs depicting the operation of an LED control device with respect to Fig. 9 according to embodiments; Fig. 13 is a block diagram representing an LED control device and a light source according to one embodiment; Fig. 14 to 16 circuit diagrams are those depicting a switch that is included in an LED control device and a light source, with reference to Fig. 13, and Fig. 17 graphs depicting the operation of an LED control device located in Fig. Figures 14 to 16 refer to embodiments; Fig. 18 is a block diagram representing a lighting device according to one embodiment; and Fig. 19 and Fig. 20 lighting devices according to embodiments are shown. DETAILED DESCRIPTION

[0016] Embodiments of the present disclosure are described below with reference to the accompanying drawings. The embodiments described herein are all exemplary and therefore the inventive concept is not limited to them and can be realized in various other forms. For each of the embodiments given in the following description, it is not excluded that it is associated with one or more features of another example or embodiment, whether mentioned herein or not, but consistent with the inventive concept.Even if, for example, facts described in one specific example are not described in another example, it is understood that these facts are related to or can be combined with the other example, unless otherwise stated in descriptions.

[0017] Fig. Figure 1 is a block diagram representing a lighting device according to one embodiment.

[0018] Referring to Fig. In one embodiment, a lighting device 10 can comprise an LED driver 20, a light source 30, and an LED control device 40 connected to a power supply 1. The LED driver 20 can supply an AC power V AC received, which is output by power source 1, and can provide a control power V DRV output to drive LEDs included in the light source 30. The LED driver 20 can, for example, supply a drive current ILED The LED driver 20 can output a constant current for driving LEDs. DRV output through a first control node 21 and a second control node 22.

[0019] The LED driver 20 can be a rectifier circuit for rectifying AC power V AC , which is output by power source 1, comprise a DC power, and a converter circuit to generate a drive power V DRV to generate the rectified DC power. In embodiments, an electromagnetic interference (EMI) filter can also be connected between the power supply 1 and the rectifier circuit. The structure and operation of the LED driver 20 are described later.

[0020] The light source 30 can comprise a plurality of LEDs, and the plurality of LEDs can provide at least one LED string. In embodiments, the plurality of LEDs can comprise first LEDs configured to emit light with a first color temperature, and second LEDs configured to emit light with a second color temperature that differs from the first color temperature. For example, the first LEDs can emit a cool white light, and the second LEDs can emit a warm white light. The first LEDs can provide at least one first LED string, and the second LEDs can provide at least one second LED string. The first LED string and the second LED string can be connected in parallel. The number of LED strings included in the light source 30 is not limited to two.

[0021] The LED control device 40 can comprise a power supply, a controller, and a switching device. The controller can be connected to an external controller and can generate a predefined control signal, and the switching device can be operated in response to the control signal. For example, the switching device can be directly connected to the light source 30 and can control a plurality of LEDs contained within the light source 30 in response to the control signal. The power supply can generate an internal power voltage that is used to operate the controller and the switching device using the drive power V. DRV is required.

[0022] Fig. Figure 2 is a block diagram showing an LED control device and a light source according to one embodiment.

[0023] Referring to Fig. 2. In one embodiment, an LED control device 100 may comprise a power supply 110, a controller 120, and a switching device 130. The LED control device 100 may be the same as the LED control device 40 described in Fig. Figure 1 is shown. The power supply 110 can provide internal power voltages V. INT1 and V INT2 generate the power required for the operation of the controller 120 and the switching device 130, using the drive power V output by the LED driver DRV In embodiments, the operating voltage of the controller 120 can differ from the operating voltage of the switching device 130; the power supply 110 can be the first internal power voltage V. INT1 supply the first controller 120, and can supply the second internal power voltage V INT2supply to the switching device 130. The power supply 110 can include a first regulator to provide the first internal power voltage V. INT1 to generate, and a second regulator to generate a second internal power voltage V INT2 to produce.

[0024] The Controller 120 can be operated by applying the first internal power voltage V INT1The controller 120 receives a control signal and can generate a control signal (CTR) to control the switching device 130. The control signal CTR can be, for example, a pulse-width modulation (PWM) signal. The controller 120 can be connected to an external controller for communication and can adjust the on-time and / or frequency of the control signal CTR in response to a control command transmitted by the external controller. For example, the controller 120 can adjust the on-time of the control signal CTR in response to a dimming command included in the control command. The controller 120 can increase the on-time of the control signal CTR if the dimming command is a brightness increase command, and the controller 120 can decrease the on-time of the control signal CTR if the dimming command is a brightness decrease command.

[0025] In various embodiments, the controller 120 can be connected to an external controller via wired or wireless communication and can receive a control command. For example, the controller 120 can be connected to an external controller via wireless communication, such as Bluetooth, Zigbee, Wi-Fi, Li-Fi, and infrared communication. Alternatively, the controller 120 can be connected to an external controller via wired communication, such as Digital Addressable Lighting Interface (DALI) or Digital Multiplex (DMX). The controller 120 can include a microcontroller unit (MCU), a communication circuit, an antenna, and an oscillator for operation by connecting to an external controller via various wired or wireless communication means.

[0026] A microcontroller unit of the Controller 120 can generate a control signal (CTR) using a control command received from an external controller via a communication circuit. As described above, the duty cycle and / or frequency of the control signal (CTR) can be changed according to the control command.

[0027] The switching device 130 can be connected to the light source 105. In one embodiment, the light source 105 can comprise two or more LED strings connected in parallel, and at least one or more of the LED strings can be connected to the switching device 130. In another embodiment, the switching device 130 can include a switch connected to the light source 105 and a switching driver to control the switch to turn it on and off. In various embodiments, the number of switches and the number of switching drivers included in the switching device 130 can vary. A detailed configuration of the switching device 130 will be described later with reference to Fig. 3 and Fig. 4 described.

[0028] At the in Fig. In the embodiment shown in Figure 2, the LED control device 100 and the light source 105 can be implemented on separate package substrates. Accordingly, the LED control device 100 can be selectively added to an existing lighting device implemented by the LED driver and the light source 105, and an additional function provided by the LED control device 100 can be implemented in the lighting device using the components of the existing lighting device in its current state.

[0029] Fig. 3 and Fig. 4 are circuit diagrams that show a switch and a light source with reference to Fig. 1 and Fig. 2 according to embodiments.

[0030] In the Fig. 3 and Fig. In the embodiments shown in Figure 4, the light source 105 can comprise a first LED string 106 and a second LED string 107, which are connected in parallel between the first control node 101 and an LED node 103. The first LED string 106 can comprise LEDs LED1 and the second LED string 107 can comprise LEDs LED2. The first LED string 106 and the second LED string 107 can be connected between the first control node 101 and the second control node 102 and can supply a drive power V. DRV received, and can be controlled by a control current I LED , which is entered via a first control node 101, emit light.

[0031] Referring to Fig. 3. The switching device 130 can comprise a switch SW and a switching driver SDV, which are connected to the LED node 103. The switching driver SDV can be operated by a control signal CTR, and the control signal CTR can be a PWM signal generated by the controller, as described above with reference to Fig. 2 described.

[0032] At the in Fig. In the embodiment shown in Figure 3, the on-time and off-time of switch SW can be determined by the duration of the control signal CTR. As the duration of the control signal CTR increases, the on-time of switch SW can increase relative to the off-time, and the brightness of the light source 105 can increase. Conversely, as the duration of the control signal CTR decreases, the brightness of the light source 105 can decrease.

[0033] In one embodiment, a dimming function for controlling the brightness of the light source 105 can be implemented by adjusting the on-time of the control signal CTR, which is input into the switching device 130. In other words, by additionally connecting an LED control device to a lighting device that might not otherwise provide the dimming function, a lighting device with the dimming function can be provided according to one embodiment. Since the switching module 130 comprises only a single switch SW and a single switching driver SDV, the manufacturing costs and power consumption of the LED control device can also be reduced.

[0034] Referring to Fig. 4. A switching device 130A can comprise a first switch SW1 and a second switch SW2, and a first switching driver SDV1 and a second switching driver SDV2. The first switch SW1 can be connected between a first LED string 106 and a second control node 102, and the second switch SW2 can be connected between the second LED string 107 and the second control node 102.

[0035] At the in Fig. In the embodiment shown in Figure 4, the first switch SW1 can be controlled by the first switching driver SDV1, and the second switch SW2 can be controlled by the second switching driver SDV2. The first switching driver SDV1 can receive a first control signal CTR1 and control the first switch SW1, and the second switching driver SDV2 can receive a second control signal CTR2 and control the second device SW2. Accordingly, the brightness of the first LED string 106 and the second LED string 107 can be controlled independently.

[0036] For example, the first LEDs, LED 1, and the second LEDs, LED 2, can emit light of different color temperatures or light of different colors. As in the Fig. In the embodiment shown in Figure 4, a user can adjust the color, brightness and / or color temperature of a light emitted by the light source 105 by independently controlling the brightness of each of the first LED string 106 and the second LED string 107 using the first switch SW1 and the second switch SW2, respectively, via a first LED node 103 and a second LED node 104.

[0037] In one embodiment, the first LED string 106 can emit a cool white light, and the second LED string 107 can emit a warm white light. Assuming that the first color temperature of the light emitted from the first LED string 106 is 6,000 K, which can be a cool white color, and the second color temperature of the light emitted from the second LED string 107 is 2,700 K, which can be a warm white color, the color temperature CCT of a light emitted from the light source 105 can be determined, for example, as shown in Table 1, depending on the on-time of the first control signal CTR1, which can determine that the first switch SW1 should be turned on / off, and the on-time of the second control signal CTR2, which can determine that the second switch SW2 should be turned on / off. Table 1 Einschaltdauereines erstenSteuersignals Einschaltdauer eines zweitenSteuersignals Farbtemperatur eines Lichts 100% 0% 6.000 K 75% 25% 5.175 K 50% 50% 4.350 K 25% 75% 3.525 K 0% 100% 2.700 K

[0038] The operation in Table 1, for example, can be implemented with a switching device that has a different configuration than the one referred to in Fig. 4. Implementation described. For example, by implementing the first switch SW1 as an NMOS transistor and the second switch SW2 as a PMOS transistor, and by connecting an output terminal of a single switching driver to a gate of the first switch SW1 and the second switch SW2, the operation described with reference to Table 1 can be implemented. In this case, the operation described with reference to Table 1 can be implemented with a single control signal.

[0039] Fig. Figure 5 is a block diagram showing an LED control device and a light source according to one embodiment.

[0040] Referring to Fig. 5. In one embodiment, the LED control device 200 can comprise a power supply 210, a controller 220, and a switching device 230, and can be connected to an external LED driver via a first control node 201 and a second control node 202. The LED control device 200 can be the same as the one described in Fig. 1 LED control device 40 shown or the one in Fig. 2 LED control devices shown 100. In one in Fig. In the embodiment shown in section 5, the configurations of the light source 205 and the switching device 230 can be adapted to the one described in section 5. Fig. 3 or Fig. The example described in section 4 should be similar.

[0041] A light source 205 can, for example, comprise at least one LED string. The switching device 230 can comprise a switch SW and a switching driver SDV, which are connected to the LED string. The switching driver SDV can control the switch SW, in response to a control signal CTR received by the controller 220, to turn it on / off, and the brightness of the light source 205 can be controlled according to the duration of the control signal CTR.

[0042] The power supply 210 can include a first regulator 211 and a second regulator 212. Both the first regulator 211 and the second regulator 212 can include an input terminal IN and an output terminal OUT, as well as a resistor terminal ADJ connected to resistors. For example, the first and second internal power voltages V can each have a value of INT1 and V INT2The output voltage at the OUT terminal varies depending on a resistance value connected to the ADJ resistance terminal.

[0043] The input terminal IN of both the first controller 211 and the second controller 212 can be connected to a node between a first diode D1 and a first capacitor C1, and the first diode D1 can be connected to the first drive node 201. Accordingly, a drive power V can be supplied. DRV Input is via the IN terminal. The OUT terminal of each of the first controller 211 and the second controller 212 can be connected to a second capacitor C2 or a third capacitor C3, which act as output capacitors.

[0044] In the first controller 211, a first resistor R1 and a second resistor R2 can be connected to the output terminal OUT. A junction between the first resistor R1 and the second resistor R2 can be connected to the resistor terminal ADJ of the first controller 211, and a value of the first internal power voltage V can be applied. INT1 The value of the first resistor R1 and the second resistor R2 can be determined based on their respective resistance values. Similarly, the value of the second internal power voltage V can be determined. INT2 depending on the resistance value of a third resistor R3 and a fourth resistor R4.

[0045] In one embodiment, the first internal power voltage V INT1 one power voltage required for the operation of the 220 controller and the second internal power voltage V INT2This can be a power voltage required for the operation of the switching device 230. The magnitude of the first internal power voltage V INT1 can, for example, be smaller than the second internal power voltage V INT2 However, one embodiment of this is not limited to this, and the magnitude of the first internal power voltage V INT1 and the second internal power voltage V INT2 This can vary depending on the specific design.

[0046] The controller 220 can generate a control signal CTR as a PWM signal and output the control signal CTR to a switching driver SDV. The controller 220 can be connected to an external controller 240 via various wired / wireless communication methods. The external controller 240 could be, for example, a mobile device such as a smartphone or tablet PC, or a lighting controller that is installed and fixed in a room adjacent to the LED control device 200.

[0047] For example, the Controller 220 can recognize a user's voice command via the external Controller 240 and generate a control signal (CTR) according to the command. In this case, the external Controller 240 can be implemented as an AI speaker instead of a mobile device or a lighting controller.

[0048] When the user transmits a command via voice using a speech recognition function of the AI ​​speaker, the controller 220 can generate a control signal CTR in response to the command and can turn the light source 205 on / off or adjust the brightness of the light source 205.

[0049] A user can control the state of the light source 205, which is included in the LED device 200, via the external controller 240, and also the state of the LED driver, which controls the drive power V. DRV The LED control device 200 monitors the voltage supplied to the LED driver. For example, if a fault occurs in at least one of the LEDs included in the light source 205, the voltage applied to the entire light source 205 may change. The LED control device 200 can monitor the voltage and / or current output from the LED driver, thus monitoring whether the LEDs are defective and also monitoring power consumption.

[0050] The power consumption of the LED driver, which supplies the light source 205 with the control power V DRVThe supplied power can be determined by a maximum value of a nominal voltage and a nominal current of the LED driver and can be defined by describing the LED driver. If a forward voltage of the LEDs included in the light source 205 is similar to a minimum voltage of a nominal voltage range of the LED driver, there may be a difference between the power consumption described in the description of the LED driver and the power actually consumed by the light source 205. In one embodiment, by further including a voltage / current sensing circuit connected to the light source 205, the controller 220 can calculate the actual power consumption of the light source 205 and can transmit the actual power consumption to the external controller 240 and notify a user of the consumption.

[0051] In one embodiment, the LED control device 200 can also determine whether the light source 205 is flickering. As described above, the LED control device 200 can include a voltage / current sensing circuit that can detect the voltage and current of the light source 205 and transmit this voltage and current to the controller 220. In this case, the controller 220 can determine whether flickering is occurring by using a ripple component of a sensing voltage that drives a control current I. LEDThe LED control device 200 detects the light emitted by the light source 205 and can transmit the result to the external controller 240. Alternatively, an optical sensor for detecting light emitted by the light source 205 can be added to the LED control device 200, and the controller 220 can calculate a precise flicker index. The flicker index can be determined to have a value between 0 and 1, with the higher the value depending on the degree of flicker. If flicker is detected, the controller 220 can adjust the frequency of the control signal CTR and reduce the flicker of the light source 205 to a minimum.

[0052] Fig. Figure 6 is a block diagram representing an LED driver according to one embodiment.

[0053] Referring to Fig. 6. In one embodiment, an LED driver 300 can comprise an electromagnetic interference (EMI) filter 310, a rectifier circuit 320, and a converter circuit 330. The LED driver 300 can be the same as the LED driver that powers the LED driver 20. Fig. 1, which was described in the previous embodiments. The EMI filter 310 can handle an AC power V AC absorb and can filter electromagnetic waves that are present in alternating current power V AC are included. The rectifier circuit 320 can convert the AC power V AC , which has been filtered out by the EMI filter 310, are converted into DC power. In one embodiment, the rectifier circuit 320 can include a diode bridge.

[0054] The converter circuit 330 can supply a drive power V to a plurality of LEDs. DRVsupply and can be configured in different ways depending on the embodiment. For example, the converter circuit 330 can include a power factor correction (PFC) converter, which can improve the power factor and increase the voltage, as well as a DC-DC converter. The converter circuit 330 can supply the drive power V DRV for controlling a multiple of LEDs using the rectified power V REC generate by rectifying the alternating current power V AC generated by the rectifier circuit 320. A quantity of voltage of the drive power V DRV can be determined by the properties of a plurality of LEDs connected to an output terminal of the converter circuit 330, for example, a forward voltage of each LED. In one embodiment, the LED driver 300 can supply an LED current I LED Output the LEDs as a constant current.

[0055] Fig. Figure 7 is a circuit diagram representing a converter circuit included in an LED driver according to one embodiment.

[0056] Fig. Figure 7 shows a converter circuit 330, which is included in the LED driver 300, in which in Fig. 6. Referring to Fig. 7 in connection with Fig. 6. The converter circuit 330 can comprise a power factor correction (PFC) converter 331, a DC-DC converter 332, and a controller 333. The PFC converter 331 can be operated as a boost converter circuit, which reduces the rectified voltage V. REC can increase the output from the rectifier circuit 320, which is in Fig. 6 is shown, and can include a first inductor L1, a first diode D1, a first capacitor C1 and a first converter switch Q1.

[0057] When the first converter switch Q1 is turned on by the controller 333, a current can flow through the rectified power V. REC to a switch resistor R S Current flows and energy can be charged into the first inductor L1. When the controller 333 switches off the first converter switch Q1, the current charged into the first inductor L1 can be discharged, resulting in a voltage higher than the rectified voltage V. REC , which is input into the PFC converter 331. In this case, a high-frequency component can be removed by the first capacitor C1, which is connected to the first diode D1.

[0058] The DC-DC converter 332, connected in series with the PFC converter 331, can be operated as a buck converter circuit and can include a second inductor L2, a second diode D2, a second capacitor C2, and a first converter switch Q2. Similar to the first converter switch Q1, the second converter switch Q2 can be controlled by the controller 333.

[0059] When the controller 331 switches on the second converter switch Q2, a current can flow to the second inductor L2, and energy can be charged into the second inductor L2. When the controller 331 switches off the second converter switch Q2, a current can flow due to the energy charged into the second inductor L2, and the drive power V DRVcan be output. The second diode D2 can provide a path through which current can flow when the second converter switch Q2 is off, and the second capacitor C2 can act as a rectifier capacitor.

[0060] The LED current I LED The current output from the LED driver 300 to a plurality of LEDs contained in a light source can have a fixed value. The LED driver 300 can also have a nominal voltage within a specified nominal range, and its power consumption can be determined by a maximum nominal voltage value and the LED current I. LED can be determined. The LED current I LED The nominal voltage and power consumption of the LED driver 300 can be provided as specifications of the LED driver 300.

[0061] However, if the sum of the forward voltages of the majority of LEDs falls below a mean voltage within the rated voltage range, for example, due to a failure where at least some of the majority of LEDs connected to the LED driver 300 are defective, the power consumption of the majority of LEDs connected to the LED driver 300 as a load may be reduced. Accordingly, there may be a difference between the power consumption described in the specifications of the LED driver 300 and the power actually consumed by the LED driver 300 during operation.

[0062] In one embodiment, the above problem can be addressed by using an LED control device connected between a light source comprising a plurality of LEDs and the LED driver 300. The LED control device can monitor the actual power consumption of the LED driver 300 by detecting the voltage applied to the plurality of LEDs and the current flowing through them. For example, if the plurality of LEDs provides a plurality of LED strings and it is detected that a relatively low voltage is applied to one of the LED strings, it can be determined that some of the LEDs in the corresponding LED strings may have failed. Accordingly, the power consumption of the LED driver 300 and also the condition of the LED strings connected to the LED driver 300 can be monitored.

[0063] Fig. Figure 8 represents graphs relating to a dimming function of an LED control device according to one embodiment.

[0064] Fig. Figure 8 shows waveforms of a control signal output by a controller of an LED control device to a switching device. The following description describes the operation of the LED control device 200 with reference to... Fig. 1, Fig. 2, Fig. 5 and Fig. 6 described.

[0065] Referring to a first graph in Fig. 8. A control signal CTR can have a duty cycle of 10%. Accordingly, a duty cycle T can be set. ON1 The control signal CTR is 10% of one period TD of the control signal CTR. In a second graph in Fig. In graph 8, the control signal CTR can have a duty cycle of 30%, and in a third graph, the duty cycle of the control signal CTR can be 60%. In a fourth graph in Fig. 8. The control signal CTR can have a duty cycle of 90%.

[0066] The control current I LED The output from the LED driver 300 can only be supplied to the light source 205 at the switch-on time T ON1 , T ON2 , T ON3 and T ON4 The control signal CTR is supplied with current. As the duty cycle of the control signal CTR increases, the brightness of the light source 205 can increase, and as the duty cycle decreases, the brightness of the light source 205 can decrease. For example, if the duty cycle of the control signal CTR is 30%, only 30% of a rated current can be supplied to the light source 205.

[0067] As with reference to Fig. As described in Figure 8, flickering in the light source 205 can occur when its brightness is adjusted using the on-time of the control signal CTR. In one embodiment, if flickering occurs in the light source 205, it can be reduced by increasing or decreasing the frequency of the control signal CTR.

[0068] Fig. Figure 9 is a block diagram showing an LED control device and a light source according to one embodiment.

[0069] Referring to Fig. 9. In one embodiment, an LED control device 400 can be connected to a first control node 401 and a second control node 402 and can be connected to a light source 405. The LED control device 400 can comprise a power supply 410, a controller 420, a switching device 430, and a current sensing circuit 440. The operation of the power supply 410, the controller 420, and the switching device 430 can be similar to the corresponding elements of the LED control device described in the previous embodiments.

[0070] At the in Fig. In the embodiment shown in Figure 9, the LED control device 400 can determine whether flickering occurs in the light source 405 by using the current sensing circuit 440. If flickering is detected in the light source 405, the controller 420 can increase or decrease the frequency of a control signal CTR. Similarly, the operating frequency of a switch, which is included in the switching device 430 and connected to the second control node 402, can increase or decrease.

[0071] The current sensing circuit 440 can, for example, be connected to the first control node 401 and can supply a control current I LEDThe controller 420 detects a signal applied to the light source 405 by the first control node 401 to generate a detection voltage. The controller 420 can determine whether flickering occurs in the light source 405 by comparing a measure of fluctuation in the detection voltage with a reference value. In one embodiment, the controller 420 can compare the difference between a maximum and a minimum value of the detection voltage over a predetermined period with a reference value, and if the difference between the maximum and minimum values ​​is greater than the reference value, the controller 420 can determine that flickering occurs in the light source 405.

[0072] If flickering is detected in the light source 405, the controller 420 can increase or decrease the frequency of the control signal CTR. Subsequently, while the switching device 430 is operating with the control signal CTR at the changed frequency, the controller 420 can again compare the measure of the detection voltage fluctuation with the reference value. If the measure of the detection voltage fluctuation is less than the reference value, the control signal CTR can be continuously output to the switching device 430 at the changed frequency; if the measure of the detection voltage fluctuation is greater than the reference value, the controller 420 can change the frequency of the control signal CTR.

[0073] The following description describes the operation of the LED control device 400 with reference to Fig. 10 to 12 described in more detail.

[0074] Fig. Figures 10 to 12 represent graphs relating to the operation of an LED control device with respect to Fig. 9 according to embodiments.

[0075] Fig. Figure 10 shows a method for the controller 420 to determine whether flickering occurs, using a detection voltage that is detected or recorded by the current detection circuit 440. A first graph in Fig. 10 represents a detection voltage that is detected by the current detection circuit 440 when no flicker occurs in the light source 405. In the first graph in Fig. 10. The detection voltage can rise or fall within a first measure of fluctuation ΔV1 for a predetermined time period.

[0076] The first measure of fluctuation ΔV1 can be smaller than a reference value for determining whether flickering occurs due to the controller 420. In this case, although no flickering occurs in the light source 405, or flickering does occur in the light source 405, the flicker cannot be detected by the human eye. Accordingly, in an embodiment based on the first graph in Fig. 10 of the controllers 420 determine that no flickering occurs in the light source 405.

[0077] The reference value can, for example, be determined proportionally to the magnitude of the detection voltage. The 420 controller, for instance, can determine the reference value by multiplying an intermediate value of the detection voltage by a predetermined coefficient. Accordingly, it can be determined that a reference value is an optimal voltage for determining whether flicker occurs, where the magnitude of the drive current I LEDand the load of the light source 405 must be taken into account.

[0078] A second graph in Fig. 10 represents a detection voltage that is detected by the current detection circuit 440 when flickering occurs in the light source 405. In the second graph in Fig. 10. The detection voltage can rise and fall within a second measure of fluctuation ΔV2, which is larger than the first measure of fluctuation ΔV1, for a predetermined time period. The second measure of fluctuation ΔV2 can be larger than a reference value at which the controller 420 determines whether flickering occurs. Accordingly, in the embodiment, the controller 420 can, based on the second graph in Fig. 10 determine that flickering occurs in the light source 405.

[0079] If flickering is detected in the light source 405, the controller 420 can adjust the frequency of the control signal CTR such that the degree of fluctuation in the detection voltage can be reduced. Referring to Fig. For example, the 420 controller can reduce the frequency of the control signal CTR.

[0080] In the Fig. In the embodiment shown in Figure 11, the duty cycle of the control signal CTR, output by the controller 420, can be 30%. The controller 420 can increase the period of the control signal CTR from an initial period TD0 to a first period TD1. While the control signal CTR is at the first period TD1, the controller 420 can compare the degree of fluctuation of the sensing voltage with a reference value. If the degree of fluctuation of the sensing voltage is less than or equal to the reference value, the controller 420 can maintain the period of the control signal CTR at the first period TD1. If the degree of fluctuation of the sensing voltage exceeds the reference value, the controller 420 can further increase the period of the control signal CTR to the second period TD2.If the sensing voltage variance exceeds the reference value while the control signal CTR has the second period TD2, the controller 420 can increase the period of the control signal CTR to the third period TD3. As described above, the controller 420 can compare the sensing voltage variance output from the current sensing circuit 440 with the reference value while reducing the frequency of the control signal CTR, and the control signal CTR can be output at the frequency where no flicker occurs or where flicker is reduced to a minimum.

[0081] Referring to Fig. 12. The controller 420 can increase the frequency of the control signal CTR to suppress flickering. As referenced in Fig. 11 described above, can be used in the Fig. In the embodiment shown in Figure 12, the duty cycle of the control signal CTR, which is output from the controller 420, is 30%.

[0082] The 420 controller can reduce the period of the control signal CTR from the initial period TD0 to the fourth period TD4. While the control signal CTR has a fourth period TD4, the 420 controller can compare the degree of fluctuation in the sensing voltage with a reference value, and if the degree of fluctuation in the sensing voltage is less than the reference value, the 420 controller can maintain the control signal CTR's period, so that it remains the fourth period TD4.

[0083] If the sensing voltage variance exceeds the reference value, the controller 420 can further reduce the period of the control signal CTR to the fifth period TD5. If the sensing voltage variance exceeds the reference value while the control signal CTR has the fifth period TD5, the controller 420 can reduce the period of the control signal CTR back to the sixth period TD6. As described above, the controller 420 can compare the sensing voltage variance output from the current sensing circuit 440 with a reference value while increasing the frequency of the control signal CTR, and determine the frequency of the control signal CTR at which no flicker occurs or flicker is reduced to a minimum.

[0084] An operation or operational processes in the embodiment described with reference to Fig. 11 and Fig. The operations described in Section 12 can be performed sequentially. For example, the controller 420 can find an optimal frequency for the control signal CTR while increasing or decreasing the frequency of the control signal CTR. If flicker is not suppressed during the operation to increase the frequency of the control signal CTR, the controller 420 can determine whether flicker occurs while decreasing the frequency of the control signal CTR. If flicker is not completely suppressed by adjusting the frequency of the control signal CTR, in one embodiment the controller 420 can generate the control signal CTR at a frequency corresponding to a frequency at which the degree of fluctuation in the sensing voltage is lowest.

[0085] Fig. Figure 13 is a block diagram showing an LED control device and a light source according to one embodiment.

[0086] Referring to Fig. 13 In one embodiment, an LED control device 500 can be connected to a first control node 501 and a second control node 502 and can be connected to a light source 505. The LED control device 500 can comprise a power supply 510, a controller 520, and a switching device 530, and the switching device 530 can comprise a leakage resistor circuit 535.

[0087] The power supply 510 can provide the controller 520 with an initial internal power voltage V INT2 using a control power V DRV supply and can supply a second internal power voltage V to the switching device 530 INT2 The controller 520 can generate a control signal CTR and can transmit the control signal CTR to the switching device 530, and the switching device 530 can control the light source 505 based on the control signal CTR.

[0088] As described above, the control signal CTR can be a PWM signal with a predetermined period and duty cycle. The control signal CTR can have a first level during the duty cycle and a second level, lower than the first level, during the duty cycle. The first level can, for example, be a level at which the switch included in the switching device 530 is turned on, and the second level can be a level at which the switch is turned off. As described above, in one embodiment, the second level can be a ground voltage.

[0089] The on-time and off-time of the control signal CTR is an extremely short time, and the control current I LED , which is from the LED driver 300 ( Fig. 6) The current output during the off-time may not be supplied to the light source 505. However, since the off-time is extremely short, the LED driver 300 may not be completely shut down during the off-time, and consequently the drive current I may be LED , which is higher than a rated current at the on-time after the off-time, is supplied to the light source 505.

[0090] In this embodiment, the switching device 530 can include a leakage resistor circuit 535 to address the problem described above. The leakage resistor circuit 535 can maintain a predetermined load impedance even during the off-time. In other words, the leakage resistor circuit 535 allows current to flow to the light source 505 even during the off-time of the control signal CTR. The current flowing through the light source 505 during the off-time can be lower than the control current I.LED , which is supplied to the light source 505 during the switch-on time. In the following description, the operation of the switching device 530, which includes the leakage resistor circuit 535, is described with reference to Fig. 14 to 17 described in more detail.

[0091] Fig. Figures 14 to 16 are circuit diagrams depicting a switch that is integrated into an LED control device and a light source, with reference to Fig. 13, and Fig. Figure 17 represents graphs relating to the operation of an LED control device located in Fig. Figures 14 to 16 are shown according to embodiments.

[0092] Operation of the switching device 530 is described with reference to Fig. Described in sections 14 to 16. Referring to Fig. 14 The light source 505 can comprise a first LED string 506 with first LEDs LED1 and a second LED string 507 with second LEDs LED2 and can be connected to the control current I LED, which is entered at the control node 501, will be operated.

[0093] The switching device 530 can be connected between the light source 505 and the second control node 502 and can comprise a first switch SW1, a second switch SW2, a first switching driver SDV1, and a second switching driver SDV2. The first switch SW1 and the second switch SW2 can be connected in parallel and can be connected together to the first LED string 506 and the second LED string 507. The first switch SW1 can be switched on / off by a first control signal CTR1, and the second switch SW2 can be switched on / off by a second control signal CTR2.

[0094] At the in Fig. In the embodiment shown in Figure 14, the first switch SW1 and the second switch SW2 can be switched on alternately. For example, the first switch SW1 can be switched on during a period when the light source 505 is emitting light, and the second switch SW2 can be switched on during a period when the light source 505 is not emitting light. Similarly, the second switch SW2 and the second switching driver SDV2 can be switched on alternately as described above. Fig. Form the described leakage resistor circuit 535.

[0095] In one embodiment, the second control signal CTR2 can be a complementary signal to the first control signal CTR1, and the first switch SW1 and the second switch SW2 can have different characteristics. For example, the first inrush current flowing through the first switch SW1 while it is open can be higher than the second inrush current flowing through the second switch SW2 while it is open. Accordingly, the light source 505 might not actually emit any light while the second switch SW2 is open.

[0096] Alternatively, the first switch SW1 and the second switch SW2 can have the same characteristics, and the first control signal CTR1 and the second control signal CTR2 can have different levels. For example, the level of the first control signal CTR1 during the on-time of the first switch SW1 can be higher than the level of the second control signal CTR2 during the on-time of the second switch SW2. Accordingly, the second inrush current can be lower than the first inrush current.

[0097] At the in Fig. In the embodiment shown in Figure 15, an impedance device 536 can be connected between the second switch SW2 and the light source 505. The impedance device 536 can comprise a high-power leakage resistor and / or a leakage inductor. Accordingly, the voltage applied to the light source 505 while the second switch SW2 is turned on can be reduced. In the embodiment shown in Figure 15, an impedance device 536 can be connected between the second switch SW2 and the light source 505. Fig. In the embodiment shown in Figure 15, the leakage resistor circuit 535 can comprise the second switch SW2, the second switching driver SDV2, and the impedance device 536. Since the impedance device 536 is connected between the second switch SW2 and the light source 505, the second switch SW2 can have the same properties as the first switch SW1, and the second control signal CTR2 can be a complementary signal to the first control signal CTR1.

[0098] At the in Fig. In the embodiment shown in Figure 16, the first switch SW1 and the second switch SW2 can be controlled by a single control signal CTR. To control the first switch SW1 and the second switch SW2 using a single control signal CTR, the second switching driver SDV2 can control the second switch SW2 as a complementary signal to the control signal CTR. As described in Figure 16, the second switching driver SDV2 can control the second switch SW2 using the complementary signal of the control signal CTR. Fig. 15 described, can be used in the Fig. In the embodiment shown in Figure 16, the leakage resistor circuit 535 comprises the second switch SW2, the second switching driver SDV2 and the impedance device 536.

[0099] Fig. Figure 17 shows waveforms of a control signal CTR. Referring to Fig. 17. The control signal CTR can have a first level V. ON exhibit a second level V during the light source's on-time 505 OFF exhibit during the light source's off time 505. The second level V OFF can be greater than the ground voltage.

[0100] At the in Fig. In the embodiment shown in Figure 17, the second switch SW2, which is included in the leakage resistor circuit 535, can be implemented as a device that is controlled by a gate voltage of the first level V ON can be switched off and by a gate voltage of the second level V OFFcan be switched on. A current path can be provided by the second switch SW2, which is switched on during the off-time of the light source 505, and the impedance device 536, which is connected to the second switch SW2, and a predetermined load impedance can be provided to an LED driver. Accordingly, during the on-time after the off-time of the light source 505, the drive current I can be LED This prevents the current from exceeding a rated current and can improve the stability of a lighting device.

[0101] Fig. Figure 18 is a block diagram representing a lighting device according to one embodiment.

[0102] Fig. Figure 18 shows a lighting device 600 that provides a dimming function. Referring to Fig. 18. The lighting device 600 can comprise a light source 610, an LED driver 620, and an LED control device 630. The LED driver 620 can supply an AC power V AC received through input terminals 603 and 604 and can supply a control power V DRV generate. The light source 610 can comprise at least one LED string, and the LED string can be controlled by drive power V. DRV to be operated. The light source 610 can be supplied with a control current I via a first control node 601. LED can be supplied and the LED control device 630 can be connected to the first control node 601 and a second control node 602.

[0103] During a Fig. In the embodiment shown in Figure 18, the LED control device 630 can comprise a power supply 631, a controller 632, a switching device 633, and a dimming switching device 634. The power supply 631 can provide a first internal power voltage V INT1, a second internal power voltage V INT2 and a third internal power voltage V INT3 output and the controller 632 can at a first internal power voltage V INT1 can be operated and the switching device 633 can be operated at the second internal power voltage V INT2 The controller 632 can output a control signal CTR to control the switching device 633, and a dimming control signal CTR. DIM , to control the dimming switching device 634, and both the control signal CTR and the dimming control signal CTR DIM can be a PWM signal. A specific operation of the power supply 631, the controller 632, and the switching device 633 can be understood by reference to other embodiments described above.

[0104] The dimming switching device 634 can be used at the third internal power voltage V INT3 can be operated and can respond to the dimming control signal CTRDIM generate a dimming control voltage. In the Fig. In the embodiment shown in 18, the LED driver 630 can provide a dimming function and can thus have dimming control connections DIM+ and DIM- as in Fig. Figure 18 illustrates the following. The dimming switching device 634 can supply the dimming control voltage, which responds to the dimming control signal CTR. DIM The generated output is sent to the dimming control terminals DIM+ and DIM-.

[0105] The dimming control signal CTR DIM This could be, for example, a PWM signal, and the dimming switching device 634 can determine the size of a dimming control voltage depending on the on-time of the dimming control signal CTR. DIM Determine. For example, if it is assumed that the dimming control voltage, which outputs the maximum brightness, is 3 V, and the on-time of the dimming control signal is CTR DIM If the dimming control voltage is 50%, it can be 1.5 V. If the on-time of the dimming control signal is CTR... DIMIf the dimming control voltage is 30%, it can be 0.9 V, and if the on-time of the dimming control signal is CTR DIM If the brightness is 80%, the dimming control voltage can be 2.4 V. The magnitude of the LED current I LED The voltage output by the LED driver 530 can change according to the magnitude of the dimming control voltage, thus adjusting the brightness of the light emitted from the light source 610. In the Fig. In the embodiment shown in Figure 18, since the dimming function is implemented by the dimming switching device 634, the on-time of the control signal CTR, which is output from the controller 632 to the switching device 633, can be a constant value.

[0106] Fig. 19 and Fig. 20 represent lighting devices according to embodiments.

[0107] Fig. Figure 19 shows an LED driver 710, which provides a dimming function, a light source 720, and an LED control device 730. Referring to Fig. The LED driver 710 can be connected to an input wiring harness 711 and an output wiring harness 715. The input wiring harness 711 can include a plurality of input terminals 712-714, which receive AC power, and the output wiring harness 715 can include a plurality of output terminals 716-719 to transmit drive power generated by the LED driver 710 to the light source 720, which comprises a plurality of LEDs. Of the plurality of output terminals 716-719, the first output terminal 716 and the second output terminal 717 can be connections for outputting the drive power. A voltage output to the first output terminal 716, for example, can be higher than a voltage output to the second output terminal 717.

[0108] The LED driver 710 can generate the drive power using the AC power input through the input wiring harness 712. The LED driver 710 can include an EMI filter, a rectifier circuit, a converter circuit, and a controller. The rectifier circuit can convert the AC power to DC power, and the converter circuit can generate the drive power using the DC power. Depending on the application of the lighting device 700, the LED driver 710 can be waterproof and dustproof. In one embodiment, the LED driver 710 can be sealed with a sealing element to prevent the ingress of moisture and dust.

[0109] In one embodiment, the LED driver 710 can output a constant current to drive the LEDs connected to the output cable harness 715, and the magnitude of the constant current can be determined by the controller of the LED driver 710. The controller can provide a dimming function to adjust the magnitude of the constant current output by the LED driver 710 within a rated current range. The controller can adjust the magnitude of the constant current according to a dimming control signal input through the dimming terminals DIM+ and DIM-, which are described above with reference to Fig. 18 are described.

[0110] Referring to Fig. The light source 720 and the LED control device 730 can be connected to the output wiring harness 715. The LED control device 730 can include a power supply 731, a controller 732, a switching device 733, and a dimming controller 734. When the controller 732 receives a control command, which includes a dimming command to change the brightness of light output by the light source 720, from an external controller via wired / wireless communication, the controller 731 can convert the dimming command into the dimming control signal, which is a PWM signal, and can transmit the dimming control signal to the dimming controller 734. The dimming controller 734 can determine a level of a dimming control voltage based on the duration of the dimming control signal and can output the dimming control voltage to the dimming control terminals DIM+ and DIM-.The magnitude of the constant current output by the LED driver 710 can increase or decrease depending on the magnitude of the dimming control voltage received through the dimming control terminals DIM+ and DIM-.

[0111] Fig. Figure 20 shows a lighting device 800, which includes an LED driver 810 that does not provide a dimming function. Referring to Fig. The LED driver 810 can comprise an input wiring harness 811 and an output wiring harness 815. The input wiring harness 811 can comprise a plurality of input terminals 812-814, which receive an AC power supply, and the output wiring harness 815 can comprise a plurality of output terminals 816 and 817 to transmit a drive power generated by the LED driver to the LEDs. The output wiring harness 815 can be connected to a light source 820 and an LED control device 830.

[0112] At the in Fig. In the embodiment shown in Figure 20, the LED driver 810 may not provide a dimming function, and accordingly, a dimming control connection may not be provided in the LED driver 810. Accordingly, in the embodiment shown in Figure 20, the following applies: Fig. In the embodiment shown in Figure 20, the dimming function is implemented by the controller 832 and the switching device 833. The controller 832 can, for example, implement the dimming function by adjusting the on-time of a control signal to switch a switch on / off that is included in the switching device 833.

[0113] According to the aforementioned embodiments, by connecting an LED control device to control nodes that can connect an LED driver and a light source, communication with an external controller and a dimming function can be implemented without replacing or upgrading the LED driver included in an existing lighting device. Accordingly, the lighting device can be implemented in a way that reduces waste from pre-installed components and increases user-friendliness.

[0114] The components, elements, modules, or units (collectively referred to as "components" in this paragraph), represented by a block in the drawings, can be embodied by a varying number of hardware, software, and / or firmware structures that perform various functions described above, according to an exemplary embodiment. These components may include, but are not limited to, the LED driver 20, the power supply 110, the controller 120, the switching driver SDV, and the dimming controller 734. According to embodiments, at least one of these components may employ a direct-connect configuration, such as a memory, a processor, a logic circuit, a lookup table, etc., which can perform the respective functions through control by one or more microprocessors or other control devices.At least one of these components can be embodied, in particular, by a module, a program, or a portion of code that includes one or more instructions for performing specific logic functions and can be executed by one or more microprocessors or other control devices. Furthermore, at least one of these components can include a processor or be implemented by a processor, such as a central processing unit (CPU) that performs the respective functions, a microprocessor, or the like. Two or more of these components can be combined into a single component that performs all the operations or functions of the combined two or more components. Also, at least some of the functions of at least one of these components can be performed by another of these components.Functional aspects of the above embodiments can be implemented in algorithms that run on one or more processors.

[0115] While the embodiments have been presented and described above, it will be apparent to the person skilled in the art that modifications and variations could be made without departing from the scope of the present disclosure as defined by the attached claims.

Claims

[1] comprising a light-emitting diode (LED) control device: a power supply (110; 210; 410; 510; 631; 731; 831) connected to a first control node (21; 101; 201; 401; 501; 601; 716; 816) and a second control node (22; 102; 202; 402; 502; 602; 717; 817) of an LED driver (20; 300; 620; 710; 810) configured to provide a control power to a light source (30; 105; 205; 405; 505; 610; 720; 820) having a plurality of LEDs; a controller (120; 220; 420; 520; 632; 732; 832) that is set up by a first internal power voltage (V INT1 ) to be operated, which is output by the power supply (110; 210; 410; 510; 631; 731; 831), and to receive a control command from an external controller (240); and a switching device (130; 130A; 230; 430; 530; 530A; 530B; 633; ​​733; 833) which is connected to the second control node (22; 102; 202; 402; 502; 602; 717; 817) and which is configured by a second internal power voltage (V INT2 ) to be operated, which is output by the power supply (110; 210; 410; 510; 631; 731; 831), and based on a control signal output from the controller (120; 220; 420; 520; 632; 732; 832), responding to the control command to control the brightness of the light source (30; 105; 205; 405; 505; 610; 720; 820), wherein the switching device (130A; 530; 530A; 530B) comprises a first switch (SW1) and a second switch (SW2) connected in parallel between the second control node (102) and the light source (105), wherein when the first switch (SW1) is switched on, the second switch (SW2) is switched off, and when the second switch (SW2) is switched on, the first switch (SW1) is switched off, and wherein the switching device (530A; 530B) has a leakage resistor (536) which is connected between the second switch (SW2) and the second control node (502) or between the second switch (SW2) and the light source (505). [2] LED control device according to claim 1, wherein the switching device (130; 130A; 230; 430; 530; 530A; 530B; 633; ​​733; 833) has for each switch (SW; SW1, SW2) a switching driver (SDV; SDV1, SDV2) which is configured to control the switch (SW; SW1, SW2) in response to the control signal (CTR; CTR1, CTR2). [3] LED control device according to claim 2, wherein the switching driver (SDV; SDV1, SDV2) is configured to output a pulse width modulation (PWM) signal to the switch (SW; SW1, SW2) with a frequency and a duty cycle determined by the control signal (CTR; CTR1, CTR2). [4] LED control device according to claim 2, wherein the controller (120; 220; 420; 520; 632; 732; 832) is configured to respond to a dimming command which is included in the control command to adjust a duty cycle of a pulse width modulation (PWM) signal which is output by the switching driver (SDV; SDV1, SDV2) to the switch (SW; SW1, SW2). [5] LED control device according to claim 4, wherein the controller (120; 220; 420; 520; 632; 732; 832) is configured to increase the on-time of the PWM signal based on the fact that the dimming command is a brightness increase command, and to decrease the on-time of the PWM signal based on the fact that the dimming command is a brightness decrease command. [6] LED control device according to one of claims 1 to 5, further comprising a current sensing circuit (440) connected to the first control node (401) and configured to generate a sensing voltage by sensing a control current applied to the light source (405), wherein the controller (420) is configured to determine whether flickering occurs in the light source (405) by comparing a measure of fluctuation of the sensing voltage with a reference value. [7] LED control device according to claim 6, wherein the controller (420) is configured to change an operating frequency of a switch which is included in the switching device (430) and is connected to the second control node (402) when the degree of fluctuation of the sensing voltage exceeds the reference value. [8] LED control device according to any one of claims 1 to 7, wherein the power supply has a first controller (211) which is configured to supply the first internal power voltage (V INT1 ) to generate, and a second regulator (212) which is set up to generate the second internal power voltage (V INT2 ) to generate, and wherein the first internal power voltage (V INT1 ) and the second internal power voltage (V INT2 ) of different sizes. [9] LED control device according to claim 8, wherein the first internal power voltage (V INT1 ) is smaller than the second internal power voltage (V INT2 ). [10] LED control device according to any one of claims 1 to 9, wherein the first switch (SW1) and the second switch (SW2) are configured to be controlled by a single pulse width modulation (PWM) signal (CTR). [11] LED control device according to any one of claims 1 to 9, wherein the first switch (SW1) is configured to be controlled by a first PWM signal (CTR1), and the second switch (SW2) is configured to be controlled by a second PWM signal (CTR2) which has a phase opposite to a phase of the first PWM signal (CTR1) and has a magnitude that differs from a magnitude of the first PWM signal (CTR1). [12] LED control device according to one of claims 1 to 11, further comprising a dimming switching device (634) which is connected to a dimming control terminal of the LED driver (620) and which is configured to output a dimming control voltage to the dimming control terminal, wherein the dimming switching device (634) is configured to convert the control signal generated by the controller (632) into the dimming control voltage and to output the dimming control voltage to the dimming control terminal. [13] Including a lighting device: a light-emitting diode (LED) driver (20; 300; 620; 710; 810) configured to generate a drive power for driving LEDs using AC power, and to output the drive power through a first drive node (21; 101; 201; 401; 501; 601; 716; 816) and a second drive node (22; 102; 202; 402; 502; 602; 717; 817); comprising a light source (30; 105; 205; 405; 505; 610; 720; 820) comprising at least one LED string comprising the LEDs and connected between the first control nodes (21; 101; 201; 401; 501; 601; 716; 816) and at least one LED node (103); and an LED control device (40; 100; 200; 400; 500; 630; 730) which is connected to the first control node (21; 101; 201; 401; 501; 601; 716; 816), the second control node (22; 102; 202; 402; 502; 602; 717; 817) and the LED node (103) between the LED driver (20; 300; 620; 710; 810) and the light source (30; 105; 205; 405; 505; 610; 720; 820), wherein the LED control device (40; 100; 200; 400; 500; 630; 730) comprises a controller (120; 220; 420; 520; 632; 732; 832) connected for communication with an external controller (240), a switching device (130; 130A; 230; 430; 530; 530A; 530B; 633; ​​733; 833) connected between the LED nodes (103) and the second control nodes (22; 102; 202; 402; 502; 602; 717; 817) configured to control the LED string in response to a control signal output by the controller, and a power supply connected to the first The first control node (21; 101; 201; 401; 501; 601; 716; 816) and the second control node (22; 102; 202; 402; 502; 602; 717; 817) are connected and are configured to output an internal power voltage for operation of the controller (120; 220; 420; 520; 632; 732; 832) and the switching device (130; 130A; 230; 430; 530; 530A; 530B; 633; ​​733; 833). wherein the switching device (530; 530A; 530B) has a first switch (SW1) and a second switch (SW2) which are connected in parallel between the LED nodes and the second control node (502), where the controller is configured to selectively turn on either the first switch (SW1) or the second switch (SW2) while the light source (505) is in operation, where the first switch (SW1) is directly connected to the LED node and the second control node (502), and wherein the second switch (SW2) is connected to the LED node and / or the second control node (502) by a resistor (536) or an inductor. [14] Lighting device according to claim 13, wherein the LED driver (300; 620; 710; 810) comprises a rectifier circuit (320) configured to rectify the AC power and a converter circuit (330) configured to generate the drive power using an output of the rectifier circuit (320). [15] Lighting device according to claim 13 or 14, wherein the LED driver (300; 620; 710; 810) comprises a first dimming control terminal and a second dimming control terminal, which are distinct from the first control node (21; 101; 201; 401; 501; 601; 716; 816) and the second control node (22; 102; 202; 402; 502; 602; 717; 817) and are configured to adjust the magnitude of a current output at the first control node (21; 101; 201; 401; 501; 601; 716; 816) based on a dimming control voltage input at the first dimming control terminal and the second dimming control terminal, and wherein the LED control device (40; 100; 200; 400; 500; 630; 730) further comprises a dimming switching device (634) which is configured to output the dimming control voltage in response to the control signal.

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