This application claims priority from Korean Patent Application No. 10-2014-0074067, filed on Jun. 18, 2014, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.
1. Field
Apparatuses consistent with exemplary embodiments relate to a light emitting diode (LED) driving device and a lighting apparatus including the same.
2. Description of the Related Art
Light emitting diodes (LEDs) are extensively used as light sources, due to properties such as lower power consumption, higher luminance, and the like. Recently, light emitting devices using LEDs are employed in general illumination devices and backlight units for larger sized liquid crystal displays. The light emitting devices are provided in the form of packages, which facilitates the installation thereof in various apparatuses.
One or more exemplary embodiments provide a lighting system capable of controlling an operation of a light emitting diode (LED) through wireless controlling, while driving the LED using alternating current (AC) power without an AC-DC (Direct Current) converter.
According to an aspect of an exemplary embodiment, a light emitting diode (LED) driving device for driving a plurality of LED groups may include a rectifier configured to rectify alternating current power to generate rectified power, an AC driver configured to control respective operations of the plurality of LED groups based on a voltage of the rectified power, and a controller configured to control an operation of the AC driver based on a control command received through a digital addressable lighting interface (DALI) communications protocol, and operate based on the rectified power received as driving power.
The LED driving device may further include a voltage dropper being configured to lower a voltage of the rectified power to be supplied as the driving power.
The AC driver may compare a voltage of the rectified power to one or more threshold voltages within a single period of the rectified power and may control respective operations of the plurality of LED groups according to a result of the comparison.
The controller may control light output from the plurality of LED groups by controlling the one or more threshold voltages.
The controller may divide the single period of the rectified power into a plurality of sections based on comparison between the voltage of the rectified power and the one or more threshold voltages, and may control light output from the plurality of LED groups by adjusting respective intervals of the plurality of sections.
The AC driver may increase a number of turned-on LED groups among the plurality of LED groups when the voltage of the rectified power is increased within a single period of the rectified power and may decrease the number of turned-on LED groups among the plurality of LED groups when the voltage of the rectified power is decreased within the single period of the rectified power.
The AC driver may increase a number of turned-on LED groups connected to one another in series, among the plurality of LED groups, when the voltage of the rectified power is increased within a single period of the rectified power, and may increase the number of turned-on LED groups connected to one another in parallel, among the plurality of LED groups, when the voltage of the rectified power is decreased within the single period of the rectified power.
The plurality of LED groups may include a first LED group and a second LED group having different levels of light output therefrom when the same amount of a current is applied to the first and second LED groups, and the first LED group may have a higher level of light output therefrom than that of the second LED group.
The AC driver may turn on the first LED group and the second LED group on when the voltage of the rectified power is increased within a single period of the rectified power, and may turn on the first LED group and turn off the second LED group when the voltage of the rectified power is decreased within the single period of the rectified power.
The AC driver may connect the first LED group and the second LED group to each other in series and turn on the first and second LED groups when the voltage of the rectified power is increased within a single period of the rectified power, and may connect the first LED group and the second LED group to each other in parallel and turns on the first and second LED groups when the voltage of the rectified power is decreased within the single period of the rectified power.
According to an aspect of another exemplary embodiment, a light emitting diode (LED) driving device for driving a plurality of LED groups may include a rectifier configured to rectify alternating current (AC) power to generate rectified power, an AC driver configured to control respective operations of the plurality of LED groups based on a voltage of the rectified power, and generate a predetermined direct current power, and a controller configured to control an operation of the AC driver based on a control command received through a DALI communications protocol, and operate based on the direct current power received as driving power.
The LED driving device may further include a charger being charged by the direct current power. The controller may operate based on an output from the charger which is supplied as the driving power.
The AC driver may compare a voltage of the rectified power to one or more threshold voltages within a single period of the rectified power and may control respective operations of the plurality of LED groups according to a result of the comparison.
The controller may control light output from the plurality of LED groups by controlling the one or more threshold voltages.
According to an aspect of still another exemplary embodiment, a lighting apparatus may include a light emitting unit including a plurality of LED groups, and an LED driving device being configured to drive the plurality of LED groups by using alternating current (AC) power, wherein the LED driving device includes an AC driver including a plurality of switching elements connected to at least one of the plurality of LED groups, and a switching controller configured to control the plurality of switching elements based on comparison between a voltage of a rectified power generated by rectifying the AC power and one or more threshold voltages, and a controller configured to control the switching controller based on a control command received through a DALI communications protocol, and operate based on the rectified power received as driving power.
The switching controller may control the plurality of switching elements based on comparison between the voltage of the rectified power and the one or more threshold voltages in a single period of the rectified power.
The AC driver may divide the single period of the rectified power into a plurality of sections based on comparison between the voltage of the rectified power and the one or more threshold voltages.
The switching controller may set a number of the switching elements that are turned-on in each of the plurality of sections.
The switching controller may turn on a different set of the switching elements in each of the plurality of sections.
The switching controller may determine a number of the LED groups being turned-on by controlling the switching elements.
The above and other aspects will be more apparent by describing certain exemplary embodiments in conjunction with the accompanying drawings, in which:
Exemplary embodiments will now be described in detail with reference to the accompanying drawings.
The disclosure may, however, be exemplified in many different forms and should not be construed as being limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
With reference to
The rectified power VREC output by the rectifier 110 may be directly applied to the light emitting unit 10 without a procedure of conversion into direct current (DC) power by an AC-DC converter or the like. The light emitting unit 10 may include a plurality of LED groups, and turn-on and turn-off of respective LED groups may be determined depending on a change in a voltage of the rectified power VREC in a single period of the rectified power VREC. The turn-on and turn-off of the plurality of respective LED groups may be determined and performed by the AC driver 120.
In the LED driving device 100 according to an exemplary embodiment, an LED may be operated by the AC driver 120 using the rectified power VREC. Based on characteristics of the rectified power VREC having a voltage increased or decreased in a single period, the AC driver 120 may adjust the number of LEDs which are turned on according to a voltage of the rectified power VREC. For example, the AC driver 120 may divide a voltage of the rectified power VREC into several sections within a single period and may turn on a relatively large number of LEDs in a section in which the voltage of the rectified power VREC is relatively high.
The controller 130 may control operations of the AC driver 120, and as an example, may receive a control command provided externally, based on a digital addressable lighting interface (DALI) communications protocol. Operations of the AC driver 120 may be controlled by the control command received by the controller 130 according to the DALI communications protocol. For example, the controller 130 may receive a control command for a reservation operation and set a time at which the AC driver 120 allows the light emitting unit 10 to emit light, or may receive a control command for brightness control and control the brightness of the light emitting unit 10 controlled by the AC driver 120. According to an exemplary embodiment, the controller 130 may include a microcontroller capable of receiving and analyzing a control command based on the DALI communications protocol.
The controller 130 may include a plurality of active elements, and thus, to operate the controller 130, a predetermined amount of driving power may be needed. In the LED driving device 100 according to an exemplary embodiment, driving power for operating the controller 130 may be supplied through the rectified power VREC. The rectified power VREC may be used as the driving power or may be lowered by the voltage dropper 140 and used as the driving power. Although the voltage dropper 140 is illustrated as a module separate from the controller 130 in
The controller 130 may be connected to an external controller via a DALI bus to receive a control command according to the DALI communications protocol. The controller 130 may be connected to the external controller through a 2-line interface, and according to the DALI protocol, which is a half-duplex scheme digital communications protocol, a signal transmitted and received between the external controller and the controller 130 may include forward frame data and backward frame data. The forward frame data may include a total of 19 bit data, and the 19 bit data may contain address information of the AC driver 120 to be controlled, command information corresponding to a command to be controlled, and the like.
With reference to
The AC driver 220 may perform control so that the plurality of LED groups included in the light emitting unit 20 may receive the rectified power VREC and are operated. In an exemplary embodiment, the AC driver 220 may change a connection structure of the plurality of LED groups included in the light emitting unit 20, instead of controlling characteristics of the rectified power VREC input to the light emitting unit 20, to secure stabilized light output operation of the light emitting unit 20.
In an exemplary embodiment, the AC driver 220 may connect the plurality of LED groups to one another in series when a voltage of the rectified power VREC is increased in a single period of the rectified power VREC, and may connect the plurality of LED groups to one another in parallel when a voltage of the rectified power VREC is decreased in a single period of the rectified power VREC. In another exemplary embodiment, the AC driver 220 may increase the number of turned-on LED groups among the plurality of LED groups when the voltage of the rectified power VREC is increased within a single period of the rectified power VREC. On the other hand, for example, when the voltage of the rectified power VREC is decreased within a single period of the rectified power VREC, the AC driver 220 may reduce the number of turned-on LED groups among the plurality of LED groups.
In an exemplary embodiment in which the number of the turned-on LED groups is changed according to an increase or a decrease in a voltage of the rectified power VREC, the LED groups may have different levels of light output. For example, a level of light output from the respective LED group may be in proportion to a time at which the respective LED group is turned on within a single period of the rectified power VREC. In other words, the LED group that is turned on for a longest period of time among the plurality of LED groups within a single of the rectified power VREC may have the highest level of light output. In this manner, luminance deviations that may occur by allowing LEDs to emit light using the rectified power VREC having AC characteristics may be significantly reduced, which will be described below with reference to
In an exemplary embodiment illustrated in
In consideration of characteristics of LEDs operating in a constant current scheme, a constant current control circuit connected to the respective LED groups of the light emitting unit 20 may be included in the AC driver 220. To control a current applied to the respective LED groups according to a voltage of the rectified power VREC increased or decreased within a single period of the rectified power VREC, the constant current circuit may receive a predetermined reference voltage. In this case, the reference voltage input to the constant current control circuit may be different according to the magnitude of a current needed for the operation of the respective LED groups, and the controller 230 may receive the reference voltage as driving power.
The control command received by the controller 230 according to the DALI communications protocol may contain address information of the light emitting unit 20 to be controlled and information for controlling of a light emission operation of the light emitting unit 20, similar to the embodiment illustrated in
With reference to
The AC driver 320 may control so that the plurality of LED groups included in the light emitting unit 30 may receive the rectified power VREC and are operated. In an exemplary embodiment, the AC driver 320 may change a connection structure of the plurality of LED groups included in the light emitting unit 30 or may adjust the number of turned-on LED groups, instead of controlling characteristics of the rectified power VREC input to the light emitting unit 30, to secure a stabilized light output operation of the light emitting unit 30. The operations of the AC driver 320 in the exemplary embodiment of
In an exemplary embodiment, the controller 330 may control operations of the AC driver 320 using a control command received according to the DALI communications protocol. The controller 330 may include a microcontroller capable of analyzing the control command according to the DALI communications protocol to control operations of the AC driver 320. Therefore, to operate the controller 330, a predetermined amount of driving power may be needed.
With reference to
In the LED driving device 300 according to an exemplary embodiment disclosed with reference to
With reference to
The constant current controller 425 may determine turn-on and turn-off of the respective switching elements SW1, SW2, SW3 and SW4 according to a voltage of rectified power output by the rectifier 410. The voltage of the rectified power may increase or decrease within a single period of the rectified power. The constant current controller 425 may turn off a portion of the switching elements SW1, SW2, SW3 and SW4 such that a relatively small number of LED groups 41, 42, 43 and 44 are turned on when a voltage of the rectified power is relatively low. On the other hand, the constant current controller 425 may control operations of the switching elements SW1, SW2, SW3 and SW4 such that a relatively large number of LED groups 41, 42, 43 and 44 are turned on when a level of the rectified power is relatively high. The control operations of the switching elements SW1, SW2, SW3 and SW4 by the constant current controller 425 and operations of the respective LED groups 41, 42, 43 and 44 performed thereby will be described with reference to
The controller 430 may control operations of the constant current controller 425, based on a control command received according to the DALI communications protocol. According to an exemplary embodiment, by controlling, at the constant current control circuit 425, a duty ratio at which the respective switching elements SW1, SW2, SW3 and SW4 are turned on and turned off, the controller 430 may adjust a level of light output from the light emitting unit 40.
Although
With reference to
The light emitting unit 50 may include the plurality of LED groups 51, 52, 53 and 54, and diodes D1, D2 and D3 may be connected between the LED groups 51, 52, 53 and 54, respectively. The diodes D1, D2 and D3 may be used in determining a connection structure of the LED groups 51, 52, and 54, together with the first and second switching circuits 521 and 523 respectively connected to the first and second nodes of the respective LED groups 51, 52, 53 and 54.
The connection structure of the LED groups 51, 52, and 54 may be determined by controlling the turn-on and turn-off of the switching elements included in the first and second switching circuits 521 and 523 through the switching controller 525. The switching controller 525 may control switching elements included in the first and second switching circuits 521 and 523 according to a voltage of the rectified power output by the rectifier 510. For example, when a voltage of the rectified power output by the rectifier 510 is increased to approximate a peak value, the switching controller 525 may control the switching elements included in the first and second switching circuits 521 and 523 such that the LED groups 51, 52, 53 and 54 may be connected to one another in series. On the other hand, when the voltage of the rectified power is reduced to approximate a reference potential, the switching controller 525 may perform control so that the LED groups 51, 52, 53 and 54 may be connected to one another in parallel.
The controller 530 may receive a control command transferred according to the DALI communications protocol and control operations of the switching controller 525. According to an exemplary embodiment, a level of light output from the light emitting unit 50 may be determined by a duty ratio of the switching elements included in the first and second switching circuits 521 and 523, the duty ratio being controlled by the switching controller 525. Therefore, the controller 530 may perform control such that the switching controller 525 may increase a duty ratio of the switching elements of the first and second switching circuits 521 and 523, to increase a level of light output from the light emitting unit 50, or may perform the control such that the switching controller 525 may decrease the duty ratio of the switching elements to reduce a level of light output from the light emitting unit 50. For example, the control of the connection structure of the LED groups 51, 52, 53 and 54 depending on an increase or a decrease in a voltage of the rectified power output by the rectifier 510 within a single period may be performed by the switching controller 525. The control performed regardless of a magnitude of the rectified power, for example, the control of light output from the light emitting unit 50, setting of reservation for a light emitting time of the light emitting unit 50, and the like, may be performed by the controller 530.
Operations of the LED driving device 400 illustrated in
In sections t1 and t8 in which the voltage of the rectified power VREC is higher than a reference potential (e.g., zero volt (0V)) and is lower than a first threshold voltage Vth1, the constant current controller 425 may turn off second to fourth switching elements SW2, SW3 and SW4 and may turn on a first switching element SW1. Thus, in the sections t1 and t8 in which the voltage of the rectified power VREC is higher than the reference potential and is lower than the first threshold voltage Vth1, a current flows in a first LED group 41 such that the first LED group 41 may emit light.
In sections t2 and t7 in which the voltage of the rectified power VREC is higher than the first threshold voltage Vth1 and is lower than a second threshold voltage Vth2, the constant current controller 425 may perform control so that the second switching element SW2 is turned on and the first, third and fourth switching elements SW1, SW3, and SW4 are turned off, to enable the first and second LED groups 41 and 42 to emit light. In addition, in sections t3 and t6 in which the voltage of the rectified power VREC is higher than the second threshold voltage Vth2 and is lower than a third threshold voltage Vth3, the third switching element SW3 may be turned on and the first, second and fourth switching elements SW1, SW2, and SW4 may be turned on such that the first to third LED groups 41, 42 and 43 may emit light. In sections t4 and t5 in which the voltage of the rectified power VREC is higher than the third threshold voltage Vth3 and is lower than a peak value Vpeak of the voltage of the rectified power VREC, the fourth switching element SW4 may be turned on and the first to third switching elements SW1, SW2 and SW3 may be turned off, such that all LED groups 41, 42, 43 and 44 may emit light.
The controller 430, which controls the AC driver 420, may receive driving power for the operation thereof, from the constant current controller 425. For example, the constant current controller 425 may compare a voltage of the rectified power VREC to the first to third threshold voltages Vth1, Vth2 and Vth3 to control the switching elements SW1, SW2, SW3 and SW4 connected to the respective LED groups 41, 42, 43 and 44. Thus, the constant current controller 425 may include a circuit for generating the first to third threshold voltages, which are predetermined or determined according to characteristics of the rectified power VREC, and the controller 430 may receive driving power generated by at least one of the first to third threshold voltages Vth1, Vth2, and Vth3, to be operated.
The AC driver 420 may control operations of the respective switching elements SW1, SW2, SW3 and SW4 by comparing the first to third threshold voltages Vth1, Vth2 and Vth3 to the level of the rectified power VREC. The controller 430 may control at least a portion of the first to third threshold voltages Vth1, Vth2 and Vth3 compared to the voltage of the rectified power VREC by the AC driver 420 or may control a time at which the respective switching elements SW1, SW2, SW3 and SW4 are turned on and turned off in the respective sections t1 to t8 of the single period of the rectified power VREC, thereby controlling the level of light output by the light emitting unit 40, and the like.
Operations of the LED driving device 500 illustrated in
In sections in which the voltage of the rectified power VREC is higher than the first threshold voltage Vth1 and lower than the second threshold voltage Vth2, the first and second LED groups 51 and 52 may be connected to each other in series and the third and fourth LED groups 53 and 54 may be connected to each other in series as illustrated in
In sections in which the voltage of the rectified power VREC is higher than the third threshold voltage Vth3 and is lower than the peak value Vpeak of the voltage of the rectified power VREC, all of the LED groups 51, 52, 53 and 54 may be connected to one another in series, as illustrated in
According to an exemplary embodiment, the controller 530, which controls operations of the switching controller 525, based on a control command received according to the DALI communications protocol, may receive driving power for the operation thereof, from the switching controller 525. The switching controller 525 may compare a voltage of the rectified power VREC to the first to third threshold voltages Vth1, Vth2 and Vth3 to control operations of the first and second switching circuits 521 and 523. To this end, the switching controller 525 may include a circuit for generating predetermined first to third threshold voltages Vth1, Vth2, and Vth3, and the controller 530 may receive driving power generated by at least one of the first to third threshold voltages Vth1, Vth2, and Vth3. In this case, the driving power supplied to the controller 530 may also be supplied through a separate charger according to an exemplary embodiment illustrated in
The controller 530 may control operations of the switching controller 525, based on the control command, to adjust a level of light output from the light emitting unit 50. According to an exemplary embodiment, the controller 530 may control at least a portion of the first to third threshold voltages Vth1, Vth2 and Vth3 compared to the voltage of the rectified power VREC through the switching controller 525 or may control a turn-on time and a turn-off time of switching devices included in the first and second switching circuits 521 and 523 in the respective sections of the single period of the rectified power VREC, thereby controlling a level of light output from the light emitting unit 50, and the like.
With reference to
With reference to
The mounting substrate 2010 may include a substrate body 2011, an upper electrode 2013, and a lower electrode 2014. In addition, the mounting substrate 2010 may include a through electrode 2012, which connects the upper electrode 2013 and the lower electrode 2014 to each other. The mounting substrate 2010 may be provided as a substrate such as a printed circuit board (PCB), a metal-core printed circuit board (MCPCB), a multilayer printed circuit board (MPCB), a flexible printed circuit board (FPCB), or the like, and the structure of the mounting substrate 2010 may be variously applied.
The wavelength conversion unit 2002 may contain a phosphor, a quantum dot, or the like. An upper surface of the encapsulation body 2003 may have a convex, dorm-shaped lens structure to adjust an angle of beam spread in light emitted through the upper surface of the encapsulation body 2003, according to an exemplary embodiment. According to another exemplary embodiment, the surface of the encapsulation body 2003 may have a concave shaped lens structure.
Referring to
In the lighting apparatus 3000, the light emitting module 3003 may engage with the external housing 3006 serving as a heat radiating unit, and the external housing 3006 may include a heat radiating plate 3004 directly contacting the light emitting module 3003 to improve a heat radiation effect. The external housing 3006 may further include a housing body 3005 connected with the heat radiating plate 3004. In an exemplary embodiment, the lighting apparatus 3000 may include the cover unit 3007 mounted on the light emitting module 3003 and having a convex lens shape. The driver 3008 may be installed in the internal housing 3009 to be connected to the external connection unit 3010, which has a structure such as a socket structure, to receive power from an external power supply. In an exemplary embodiment, the driver 3008 may convert the received power into a current source suitable for driving the semiconductor light emitting device 3001 of the light emitting module 3003 and supply the converted power. The driver 3008 may include at least one of the LED driving devices 100, 200, 300, 400 and 500 illustrated in
According to exemplary embodiments, an AC driver may drive an LED using rectified power output by a rectifier without a separate AC-DC converter. To provide driving power of a controller, which receives a control command through the DALI communications protocol to control luminance of the LED, a light emission time, setting for reservation thereof, and the like, rectified power, or DC power generated in a circuit of the AC driver may be used. Accordingly, an LED driving device may be simply implemented.
While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope as defined by the appended claims.
Number | Date | Country | Kind |
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10-2014-0074067 | Jun 2014 | KR | national |