This application claims the benefit under 35 U.S.C. Section 119 of Korean Patent Application Serial No. 10-2013-0168139, entitled “Power Driver For LED (Light Emitting Diode) Illumination And Control Method Thereof” filed on Dec. 31, 2013, which is hereby incorporated by reference in its entirety into this application.
1. Technical Field
Some embodiments of the present disclosure relate to a power driver for light emitting diode (LED) illumination and a control method thereof, and more particularly, to a power driver for light emitting diode (LED) illumination and a control method thereof which may have a wide output voltage range by performing, for example, but not limited to, a skip mode control.
2. Description of the Related Art
A power driver for LED illumination may supply a constant current to an LED module by a control of current. In this case, an output voltage may be determined by a LED forward voltage Vf of the LED module. When Vf of the LED is out of the output voltage range of power, the current may not be controlled and thus the LED may not emit light.
The power driver for LED illumination constantly controls an output current in terms of characteristics of the LED module and the output voltage is designed to meet Vf of the LED module. If the output voltage range is narrow, as illustrated in
Some embodiments of the present disclosure may provide a power driver for light emitting diode (LED) illumination and a control method thereof which may generally have a wide output voltage range by performing a skip mode control in a low voltage region of an output range of a DC/DC converter.
According to an exemplary embodiment of the present disclosure, a power driver for LED illumination may comprise a power correction unit receiving an AC voltage from the outside, rectifying the received AC voltage into a DC voltage, and correcting a power factor of the rectified DC voltage; and a DC/DC converter unit receiving the DC voltage from the power correction unit and converting the received DC voltage into a DC voltage which has a magnitude different from the received DC voltage and is supplied to an LED module. The DC/DC converter unit may comprise a skip control unit, to which a current flowing in the LED module driven by receiving an output from the DC/DC converter unit is fed back, to detect a magnitude of the current and to output a signal for a skip mode control depending on the detected magnitude of the current.
The DC/DC converter unit may include a DC/DC controller which feeds back with the current flowing in the LED module to detect the magnitude of the current and controls a current flowing in a primary side winding of a transformer included in the DC/DC converter unit depending on the detected magnitude of the current.
The skip control unit may be configured of a processor (IC) which may compare the feeding back current with a reference current and output the signal for the skip mode control to the DC/DC controller depending on the comparison result.
The skip control unit may include: a comparator receiving and comparing a voltage signal sensed by an auxiliary winding disposed at the primary wiring side of the transformer and a skip carrier signal generated from a skip carrier generator, and outputting a skip mode operation signal when the sensed voltage is lower than a skip carrier level; and an OR gate receiving and OR-operating an output signal from the comparator and a feedback signal from the LED module and outputting the signal for the skip mode control to the DC/DC controller.
The skip control unit may have a structure to receive a skip control signal from an external main control unit and transfer the received skip control signal to the DC/DC controller.
The power factor correction unit may be, for example, but not limited to, a boost converter.
The DC/DC converter unit may be, for instance, but not limited to, an inductor-inductor-capacitor (LLC) resonance converter.
According to another exemplary embodiment of the present disclosure, there may be provided a method of controlling a power driver for LED illumination including a power correction unit and a DC/DC converter unit. The method may comprises: receiving, by the power correction unit, an AC voltage from the outside, rectifying the received AC voltage into a DC voltage, and correcting a power factor of the rectified DC voltage; and receiving, by the DC/DC converter unit, the DC voltage from the power correction unit and converting the received DC voltage into a DC voltage which has a magnitude different from the received DC voltage and is supplied to an LED module. A skip control unit, which may be included in the DC/DC converter unit, may feed back with a current flowing in the LED module driven by receiving the output from the DC/DC converter unit to detect a magnitude of the current and output a signal for a skip mode control depending on the detected magnitude of the current.
The outputting of the signal for the skip mode control by the skip control unit may include: receiving and comparing, by a comparator, a voltage signal sensed by an auxiliary winding disposed at a primary side of a transformer and a skip carrier signal generated from a skip carrier generator, respectively, and outputting a skip mode operation signal when the sensed voltage is lower than a skip carrier level; and receiving and OR-operating, by an OR gate, an output signal from the comparator and a feedback signal from the LED module and outputting the signal for the skip mode control to the DC/DC controller.
The outputting of the signal for the skip mode control by the skip control unit may be performed by a method of directly receiving a skip control signal from an external main control unit by the skip control unit and transferring the received skip control signal to the DC/DC controller.
Terms and words used in the present specification and claims are not to be construed as a general or dictionary meaning, but are to be construed to meaning and concepts meeting the technical ideas of the present invention based on a principle that the inventors can appropriately define the concepts of terms in order to describe their own inventions in the best mode.
Throughout the present specification, unless explicitly described to the contrary, “comprising” any components will be understood to imply the inclusion of other elements rather than the exclusion of any other elements. A term “part”, “module”, “device”, or the like, described in the specification means a unit of processing at least one function or operation and may be implemented by hardware or software or a combination of hardware and software.
Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.
As illustrated in
Referring to
The power factor correction unit 210 may receive an AC voltage from an external AC power supply, rectify the received AC voltage into a DC voltage, and correct a power factor of the rectified DC voltage. The power factor correction unit 210 may comprise an electromagnetic interference (EMI) filter 211, a first bridge diode 212, a power factor correction (PFC) controller 213, and an IC power supply unit 214.
The EMI filter 211 may remove a high frequency noise component mixed in the external AC power supply. The first bridge diode 212 may rectify the AC voltage input through the EMI filter 211 into the DC voltage. The PFC controller 213 may correct a power factor of the DC voltage rectified by the first bridge diode 212 by controlling an inductance component of an inductor Lb and a capacitance component of a capacitor Clink. The IC power supply unit 214 may supply a voltage acquired from an output terminal of the first bridge diode 212 to the power factor correction controller 213 and a DC/DC controller 223 as a driving power. For example, a boost converter may be used for the power factor correction unit 210. However, the present invention is not limited thereto, and therefore an apparatus or a circuit in another type having a power factor correction function may be used.
The DC/DC converter unit 220 may receive the DC voltage from the power factor correction unit 210, and may convert the received DC voltage into a DC voltage which may have a magnitude different from the received DC voltage and be supplied to the LED module 230. The DC/DC converter unit 220 may comprise a transformer 221, the second bridge diode 222, a DC/DC controller 223, and a skip control unit 224.
The transformer 221 may transform the DC voltage input via the power factor correction unit 210 into a DC voltage which may have a magnitude different from the DC voltage input. The second bridge diode 222 may rectify a DC voltage output from a secondary side winding of the transformer 221. The DC/DC controller 223 may control a turn on/off of semiconductor switch elements QA and QM (for example, MOSFET) to interrupt a flow of current in a primary side winding of the transformer 221. The skip control unit 224 may feed back with a current flowing in the LED module 230 driven by receiving the output from the DC/DC converter unit 220 to detect a magnitude of the current and output a signal for a skip mode control depending on the detected magnitude of the current. For instance, an inductor-inductor-capacitor (LLC) resonance converter may be used for the DC/DC converter unit 220. However, the present invention is not limited thereto, and therefore another type of apparatus or circuit having a DC/DC converter function may be used.
The DC/DC controller 223 may be configured to receive the current flowing in the LED module 230 as a feedback input to detect a magnitude of the current and to output the signal for controlling the current flowing in the primary side winding of the transformer 221 to the semiconductor switch elements QA and QM depending on the detected magnitude of the current.
Further, the skip control unit 224 may be configured of a processor (IC) which may compare the feed-back current with a reference current and output the signal for the skip mode control to the DC/DC controller 223 depending on the comparison result.
For instance, as illustrated in
Further, the skip control unit 224 may be configured of a structure to receive the skip control signal from an external main control unit (not illustrated) and transfer the received skip control signal to the DC/DC controller 223.
Herein, an operation relationship of the skip control unit 224 as described above will be briefly described with reference to
The comparator 302 may compare a pulse signal (for example, skip carrier) level with the sensed voltage from the auxiliary winding 310 to operate the skip mode operation when the sensed voltage falls below the pulse signal (e.g. skip carrier) level. Further, when the OR gate 303 receives a feedback control signal and then receives the output signal, that is, the skip carrier signal of the comparator 302, the OR gate 303 may output a signal for the skip mode control is output to the DC/DC controller 223. Therefore, the DC/DC controller 223 may perform the skip control operation.
Next, the control method of the power driver for LED illumination according to exemplary embodiments of the present disclosure will be described below.
Referring to
When the power factor correction is completed, the DC/DC converter unit 220 may receive the DC voltage from the power factor correction unit 210 and may convert the received DC voltage into a DC voltage which may have a magnitude different from the received DC voltage and may be supplied to the LED module 230 (step S402). For instance, the DC/DC converter unit 220 may output the DC voltage having the magnitude different from the DC voltage input to the primary side winding of the transformer 221 through the secondary side winding of the transformer 221 depending on a turn ratio of the primary and secondary side of the transformer 221 of the DC/DC converter unit 220. The LED module 230 may be driven by being applied with the DC voltage output from the DC/DC converter unit 220.
When the LED module 230 is driven, the skip control unit 224, which is disposed or included in the DC/DC converter unit 220, may receive a feedback input which may be the current flowing in the LED module 230 driven by receiving the output from the DC/DC converter unit 220 (step S403).
The skip control unit 224 may detect the magnitude of the feed-back current and may output the signal for the skip mode control depending on the detected magnitude of the current (step S404).
Herein, the process of outputting the signal for the skip mode control by the skip control unit 224 will be additionally described with reference to
Referring to
In the determining of the step 5502, if it is determined that the sensed voltage is not smaller than the skip carrier level, the comparator 302 may not output any signal at all. Therefore, the DC/DC controller 223 may perform the usual (general) control according to the input of the feedback signal. Further, in the determining of the step S502, if it is determined that the sensed voltage is smaller than the skip carrier level, the comparator 302 may output the skip mode operation signal (step S503).
When the skip mode operation signal is output by the comparator 302, the OR gate 303 may receive and OR-operate the output signal from the comparator 302 and the feedback signal from the LED module 230 (step S504). When acquiring the skip mode operation signal by receiving the feedback signal and the skip mode operation signal, the comparator 302 may output the signal for the skip mode control to the DC/DC controller 223 (step S505).
As described above, outputting the signal for the skip mode control by the skip control unit 224 may be implemented by the method of directly receiving the skip control signal from the external main control unit (not illustrated) by the skip control unit 224 and transferring the received skip control signal to the DC/DC controller 223.
Meanwhile,
Herein, briefly describing the definition and the basic concept of the ‘skip mode control’ with reference to
When the skip mode control is performed in the low voltage region of the output voltage of the transformer 221 as illustrated in
As illustrated in
As described above, according to some exemplary embodiments of the present disclosure, to commonly use the LED illumination power, the control method (skip control) may have the wide output voltage range, such that one power driver may be used in the plurality of LED illumination module.
As described above, the power driver for LED illumination and the control method thereof according to some exemplary embodiments of the present disclosure may generally have the wide output voltage range by performing the skip mode control in the low voltage region of the output range of the DC/DC converter (transformer), such that one power driver may be used in the plurality of different LED lighting devices. Therefore, costs required for the power driver may be reduced.
According to some exemplary embodiments of the present disclosure, the wide output voltage range may be generally implemented by performing the skip mode control in the low voltage region of the output range of the DC/DC converter (transformer), such that one power driver may be used in the plurality of different LED lighting devices.
Although exemplary embodiments of the present invention have been disclosed for illustrative purposes, the present invention is not limited thereto, but those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Therefore, the protection scope of the present invention must be analyzed by the appended claims and it should be analyzed that all spirits within a scope equivalent thereto are included in the appended claims of the present disclosure.
Number | Date | Country | Kind |
---|---|---|---|
10-2013-0168139 | Dec 2013 | KR | national |