The LED Lighting Apparatus That Suppress Power Factor Decline And Total Harmonic Distortion Rise By Varying The Output Current Based On The Temperature Sensed By The Converter And The LED Module, And The Its Driving Method

Abstract

The present invention relates to an LED lighting device and a driving method thereof that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter and the LED module. More specifically, the invention relates to an LED lighting device and a driving method thereof that can improve power quality by suppressing power factor reduction and harmonic distortion increase in the current decay-section (low output) while varying the output current by sensing the temperature of the LED module and the LED converter in real time, respectively, and can suppress blinking (interference) caused by external heating devices, etc. by using a converter designed based on a 2-stage design.

Description

Technology Field

[0001] The present invention relates to an LED lighting device and a driving method thereof that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter and the LED module. More specifically, the invention relates to an LED lighting device and a driving method thereof that can improve power quality by suppressing power factor reduction and harmonic distortion increase in the current decay-section (low output) while varying the output current by sensing the temperature of the LED module and the LED converter in real time, respectively, and can suppress blinking (interference) caused by external heating devices, etc. by using a converter designed based on a 2-stage design. Background Technology

[0003] Light Emitting Diodes (LEDs) have established themselves as a core technology replacing conventional lighting sources, based on advantages such as high energy efficiency, long lifespan, and excellent durability. Since LED devices must be driven by direct current (DC) power due to the semiconductor characteristics, a power supply device such as an AC-DC converter—specifically an SMPS (Switching Mode Power Supply)—is essential in environments using standard AC commercial power.

[0004] Heat generated in such LED lighting devices is a very important factor that directly affects the performance and lifespan of the device. Heat is mainly generated in the LED module itself, which emits light, as well as in the switching elements and transformers inside the converter (SMPS) that converts and controls power. Overheating of the LED module causes a decrease in luminous efficiency, changes in color temperature, and a shortened lifespan, while overheating of the converter can cause deterioration and damage to internal components, potentially leading to the failure of the entire lighting device. To address these problems, various technologies have been disclosed in the past to protect LED lighting devices by detecting temperature.

[0005] Conventional technologies for protecting LED lighting devices by detecting temperature include Korean Registered Patent No. 10-1616715 (Device and method for preventing overheating of an LED lighting fixture), Korean Registered Patent No. 10-2101564 (Temperature control method and device for an LED display), Korean Registered Patent No. 10-0735460 (LED driving control circuit having a temperature compensation function), and Korean Published Patent No. 10-2012-0017916 (LED protection circuit due to temperature rise), all of which disclose technologies for preventing overheating by measuring the temperature of the LED module side. These technologies commonly disclose a method of protecting LED elements by attaching a temperature sensor to the LED module or its heat sink and lowering the output current or cutting off the power supply when the measured temperature exceeds a threshold.

[0006] On the other hand, U.S. registered patent US 11,363,696 B2 (Over-temperature protection circuit of an LED driving power supply) discloses a protection circuit for preventing overheating of an LED driving power supply, i.e., a converter. This focuses on a technology that detects and protects against overheating of the converter itself by placing a temperature sensor inside the converter. However, the aforementioned prior art has the following limitations.

[0007] First, prior art technologies individually measure and control the temperature of only one of the two main causes of heat generation, namely the LED module or the converter. As a result, they cannot effectively respond to situations where, for example, the temperature of the LED module is normal but only the converter overheats inside a sealed fixture, or vice versa. In other words, no technology has been disclosed that ensures stability by comprehensively considering the thermal state of the entire system.

[0008] Second, the aforementioned prior art does not provide any solution to the problems of power factor degradation and harmonic distortion increase that occur during the process of lowering the output current as the temperature rises. Typically, the power factor compensation circuit of an SMPS (Switching Mode Power Supply) equipped in an LED lighting fixture is designed to deliver optimal performance under specific load conditions; however, if the output current (i.e., the load) is forcibly reduced for overheating protection, the operating point of the power factor compensation circuit deviates from the optimal point. This results in a rapid decrease in power factor and an increase in total harmonic distortion (THD), causing serious problems that degrade power quality and reduce energy efficiency. Nowhere in the prior art literature is there any recognition of these secondary problems or any specific circuit configuration or control method to prevent them disclosed.

[0009] Therefore, there is a need to develop a new LED lighting device and a driving method thereof that can stably protect the system by simultaneously considering the temperatures of both the LED module and the converter, and maintain high power factor and low harmonic distortion characteristics even during overheat protection operation. Prior art literature

[0011] Republic of Korea Registered Patent No. 10-1616715 (April 25, 2016) Republic of Korea Registered Patent No. 10-2101564 (April 9, 2020) Republic of Korea Registered Patent No. 10-0735460 (June 27, 2007) Republic of Korea Published Patent No. 10-2012-0017916 (February 29, 2012) U.S. Registered Patent US 11,363,696 B2 (June 14, 2022) The problem to be solved

[0012] The present invention aims to provide an LED lighting device and a driving method thereof that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter and the LED module. More specifically, the invention aims to provide an LED lighting device and a driving method thereof that can improve power quality by suppressing power factor reduction and harmonic distortion increase in the current decay section (low output) while varying the output current by sensing the temperature of the LED module and the LED converter in real time, respectively, and can suppress blinking (interference) caused by external heating devices, etc. by using a converter designed based on a 2-stage design. means of solving the problem

[0014] In order to solve the above problems, in one embodiment of the present invention, an LED lighting device that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter and the LED module comprises: an AC input unit that receives AC power from an external source; an EMI filter unit including a plurality of filter elements for attenuating noise included in the AC power; a rectification and smoothing unit that converts the AC power passing through the EMI filter unit into DC power by rectifying and smoothing it; and an active power factor control unit including a power factor compensation circuit unit that actively controls the power factor of the DC power output from the rectification and smoothing unit so that the waveform of the input current becomes in phase with the waveform of the input voltage. The present invention provides an LED lighting device comprising: a transformer having a primary winding section and a secondary winding section that are electrically isolated, a transformer section that converts a pulse power applied to the primary winding section to a predetermined voltage level in conjunction with a switching operation in the active power factor control section and outputs it to the secondary winding section; a DC-DC dimming control section that rectifies the power converted through the transformer section into a DC power source and controls the amount of output current output to the LED module based on a dimming voltage value determined according to the respective temperatures of the converter and the LED module; and an LED module that is driven by receiving the output current.

[0015] In one embodiment of the present invention, the LED lighting device may further include a surge protection unit comprising: a varistor disposed between the AC input unit and the EMI filter unit and capable of protecting the downstream circuit when an overvoltage is introduced through the AC input unit; and a fuse that blocks overcurrent.

[0016] In one embodiment of the present invention, the EMI filter unit may include an X capacitor connected between two AC input lines into which the AC power is input to attenuate differential mode noise; and a Y capacitor connected between the AC input lines and ground, respectively, to provide a ground path for common mode noise.

[0017] In one embodiment of the present invention, the EMI filter section may further include a choke section comprising one or more chokes, wherein two windings are wound on a single core, so as to cancel out the magnetic field generated by the differential mode current and provide a common mode current with an impedance higher than that of the differential mode current to attenuate noise included in the AC power source.

[0018] In one embodiment of the present invention, the rectifying smoothing unit may include: a bridge unit that converts the AC power into pulsating DC by connecting four diodes in a bridge form; and a capacitor connected in parallel to the output terminal of the bridge unit, which charges when the pulsating DC rises and discharges when it falls, and reduces the ripple component of the pulsating DC through charging and discharging according to the rise and fall of the pulsating DC.

[0019] In one embodiment of the present invention, the transformer part may further include an auxiliary winding part that generates feedback power proportional to the voltage output from the secondary winding part.

[0020] In one embodiment of the present invention, the active power factor control unit may further include a power factor controller unit comprising an IC element for controlling the power factor compensation circuit unit.

[0021] In one embodiment of the present invention, the power factor controller may include: a feedback module that receives feedback power applied through the auxiliary winding section of the transformer section, derives an error value between the feedback voltage of the feedback power and a reference voltage, and amplifies the error value; and a switching frequency generation section that generates a switching frequency having a frequency value determined based on the amplified error value and transmits the generated switching frequency to the power factor compensation circuit section.

[0022] In one embodiment of the present invention, the LED lighting device further includes a temperature sensing module, wherein the temperature sensing module includes a first temperature measuring unit provided in the DC-DC dimming control unit; and a second temperature measuring unit provided in the LED module, and the first temperature measuring unit and the second temperature measuring unit may be connected in parallel with each other.

[0023] In one embodiment of the present invention, the first temperature measuring unit includes a first NTC thermistor whose resistance value decreases as the temperature rises, and the second temperature measuring unit includes a second NTC thermistor whose resistance value decreases as the temperature rises, and the temperature sensing module can determine the temperature of the LED lighting device based on the parallel sum of the resistance value of the first NTC thermistor and the resistance value of the second NTC thermistor.

[0024] In one embodiment of the present invention, the DC-DC dimming control unit performs the steps of: deriving a dimming voltage value according to a temperature determined by the temperature sensing module; determining a current value of the output current based on the dimming voltage value; and transmitting the output current corresponding to the determined current value to the LED module; wherein the output current is determined in proportion to the dimming voltage value, and the current value of the output current may be greater than or equal to a preset minimum current value and less than or equal to a preset maximum current value.

[0025] In order to solve the above problems, in one embodiment of the present invention, a driving method for an LED lighting device that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter and the LED module comprises: an AC input step of receiving AC power from an external source; an EMI filter step of attenuating noise included in the AC power using a plurality of filter elements; a rectification and smoothing step of converting the AC power filtered in the EMI filter step into DC power by rectifying and smoothing it; and an active power factor control step of actively controlling the power factor so that the waveform of the input current becomes in phase with the waveform of the input voltage in the DC power output by the rectification and smoothing step. A method for driving an LED lighting device is provided, comprising: a transformer section including a transformer in which a primary winding section and a secondary winding section are electrically isolated; a transforming step in which a pulse power applied to the primary winding section is converted to a predetermined voltage level in conjunction with a switching operation in the active power factor control step and then output to the secondary winding section; a DC-DC dimming control step in which the power converted through the transforming step is rectified into a DC power and the amount of output current output to the LED module is controlled based on a dimming voltage value determined according to the respective temperatures of the converter and the LED module; wherein the LED module included in the LED lighting device is driven by receiving an output current.

[0026] In one embodiment of the present invention, the driving method of the LED lighting device further includes a surge protection step that can protect the circuit at the subsequent stage when an overvoltage is introduced in the AC input step by applying the AC power applied through the AC input step to a varistor and a fuse, and the AC power output after the surge protection step can be transmitted to the filter element for the EMI filter step.

[0027] In one embodiment of the present invention, the plurality of filter elements include an X capacitor connected between two AC input lines into which the AC power is input; and a Y capacitor each connected between the AC input line and ground to provide a ground path for common mode noise; and the EMI filter step may include a step of attenuating differential mode noise through the X capacitor; and a step of attenuating common mode noise through the Y capacitor.

[0028] In one embodiment of the present invention, the plurality of filter elements may further include a choke section comprising one or more chokes, wherein two windings are wound on a single core, so as to cancel out the magnetic field generated by the differential mode current and provide a common mode current with an impedance higher than that of the differential mode current, thereby attenuating noise included in the AC power source.

[0029] In one embodiment of the present invention, the rectification and smoothing step may include: a step of converting the AC power source into pulsating DC by means of a bridge portion in which four diodes are connected in a bridge form; and a step of reducing the ripple component of the pulsating DC by means of a capacitor connected in parallel to the output terminal of the bridge portion, by charging the capacitor when the pulsating DC rises and discharging the capacitor when the pulsating DC falls.

[0030] In one embodiment of the present invention, the transformer part further includes an auxiliary winding part, and the transforming step may include a step of generating feedback power proportional to the voltage output from the secondary winding part.

[0031] In one embodiment of the present invention, the active power factor control step may include a power factor control step that actively controls the power factor using an IC element.

[0032] In one embodiment of the present invention, the power factor control step comprises: a feedback step that receives feedback power applied through the auxiliary winding part of the transformer part, derives an error value between the feedback voltage of the feedback power and a reference voltage, and amplifies the error value; and a switching frequency generation step that generates a switching frequency having a frequency value determined based on the amplified error value; and the power factor control step can actively control the power factor based on the generated switching frequency.

[0033] In one embodiment of the present invention, the driving method of the LED lighting device further includes a temperature sensing step performed in a temperature sensing module, wherein the temperature sensing module includes a first temperature measuring unit provided in a DC-DC dimming control unit where the DC-DC dimming control step is performed; and a second temperature measuring unit provided in the LED module, wherein the first temperature measuring unit and the second temperature measuring unit are connected in parallel with each other.

[0034] In one embodiment of the present invention, the first temperature measuring unit includes a first NTC thermistor whose resistance value decreases as the temperature rises, and the second temperature measuring unit includes a second NTC thermistor whose resistance value decreases as the temperature rises, and the temperature sensing step can determine the temperature of the LED lighting device based on the parallel sum of the resistance value of the first NTC thermistor and the resistance value of the second NTC thermistor.

[0035] In one embodiment of the present invention, the DC-DC dimming control step comprises: a step of deriving a dimming voltage value according to a temperature determined by the temperature sensing module; a step of determining a current value of the output current based on the dimming voltage value; and a step of transmitting the output current corresponding to the determined current value to the LED module; wherein the output current is determined in proportion to the dimming voltage value, and the current value of the output current may be greater than or equal to a preset minimum current value and less than or equal to a preset maximum current value. Effects of the invention

[0037] According to one embodiment of the present invention, by detecting the temperatures of both the converter and the LED module to precisely determine the overall thermal state of the system and responding preemptively thereto, it is possible to achieve the effect of significantly improving the stability and reliability of the LED lighting device.

[0038] According to one embodiment of the present invention, since the output current is controlled by detecting not only the temperature rise of the LED module but also the overheating of the converter itself, it is possible to achieve the effect of preventing deterioration and damage to the converter components even in a sealed environment.

[0039] According to one embodiment of the present invention, the performance of the power factor compensation circuit is prevented due to overheating of the converter, and the effect of continuously maintaining a high power factor is achieved by stably controlling the input current waveform.

[0040] According to one embodiment of the present invention, the effect of suppressing electromagnetic interference (EMI) and parasitic oscillations can be achieved by eliminating switch noise.

[0041] According to one embodiment of the present invention, by effectively managing thermal stress in the system, the lifespan of key components within the LED element and converter can be extended, thereby improving the overall durability of the lighting device.

[0042] According to one embodiment of the present invention, by comprehensively reflecting temperature information from two points through a simple circuit configuration in which two temperature measuring units (NTC thermistors) are connected in parallel, it is possible to achieve the effect of implementing an efficient overheat protection function without complex control logic or an additional microcontroller.

[0043] According to one embodiment of the present invention, when overheating is detected, the output current is gradually reduced rather than simply cutting off the power, so the effect of stably protecting the lighting device without causing inconvenience to the user can be achieved.

[0044] According to one embodiment of the present invention, by maintaining stable power characteristics (power factor, harmonics) even under abnormal operating conditions such as overheating, it is possible to achieve the effect of being flexibly applied to various lighting environments requiring high quality and high reliability.

[0045] According to one embodiment of the present invention, even when the output current decreases due to temperature, the stability of the compensation loop in the active power factor control unit is secured, thereby preventing malfunction of the controller (IC) and thereby enabling the effect of extending the lifespan of the LED lighting device.

[0046] According to one embodiment of the present invention, by automatically adjusting the switching frequency, the effect of increasing efficiency during light load can be achieved. Brief explanation of the drawing

[0048] FIG. 1 schematically illustrates the internal configuration of an LED lighting device according to one embodiment of the present invention. FIG. 2 schematically illustrates a circuit diagram of an AC input section, a surge protection section, and an EMI filter section according to one embodiment of the present invention. FIG. 3 schematically illustrates a circuit diagram of a rectification and smoothing section according to one embodiment of the present invention. FIG. 4 schematically illustrates the internal configuration of an active power factor control unit according to one embodiment of the present invention. FIG. 5 schematically illustrates a circuit diagram of an active power factor control unit according to one embodiment of the present invention. FIG. 6 schematically illustrates the connection relationships between each of the internal components of an active power factor control unit according to one embodiment of the present invention. FIG. 7 schematically illustrates two switching frequencies having different Ton according to one embodiment of the present invention. FIG. 8 schematically illustrates the internal configuration of a transformer part according to one embodiment of the present invention. FIG. 9 schematically illustrates a circuit diagram of a transformer section according to one embodiment of the present invention. FIG. 10 schematically illustrates the configuration of a temperature sensing module provided in each of the DC-DC dimming control unit and the LED module according to one embodiment of the present invention. FIG. 11 schematically illustrates the process of performing a temperature sensing step according to one embodiment of the present invention. FIG. 12 schematically illustrates a characteristic graph of an NTC thermistor included in a temperature sensing module according to one embodiment of the present invention. FIG. 13 schematically illustrates an output current graph according to a dimming voltage value according to an embodiment of the present invention. FIG. 14 schematically illustrates a graph of the switching frequency according to the amplified error value according to one embodiment of the present invention. Specific details for implementing the invention

[0049] Hereinafter, various embodiments and / or aspects are disclosed with reference to the drawings. For illustrative purposes, numerous specific details are disclosed in the following description to aid in a general understanding of one or more aspects. However, it will also be recognized by those skilled in the art that these aspects may be practiced without such specific details. The following description and the accompanying drawings describe specific exemplary aspects of one or more aspects in detail. However, these aspects are exemplary, and some of the various methods in the principles of the various aspects may be used, and the description is intended to include all such aspects and their equivalents.

[0051] In addition, various aspects and features will be presented by a system that may include multiple devices, components and / or modules, etc. It should also be understood and recognized that various systems may include additional devices, components and / or modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in relation to the drawings.

[0052] Terms such as “embodiment,” “example,” “aspect,” “example,” etc. as used herein may not be interpreted as implying that any aspect or design described is superior or more advantageous than other aspects or designs. Terms used below, such as “part,” “component,” “module,” “system,” “interface,” etc., generally refer to computer-related entities and may, for example, refer to hardware, a combination of hardware and software, or software.

[0053] Additionally, the terms “comprising” and / or “comprising” should be understood to mean that the relevant feature and / or component is present, but not to exclude the presence or addition of one or more other features, components and / or groups thereof.

[0054] Additionally, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0055] Furthermore, in the embodiments of the present invention, all terms used herein, including technical or scientific terms, unless otherwise defined, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in the embodiments of the present invention.

[0057] FIG. 1 schematically illustrates the internal configuration of an LED lighting device (100) according to one embodiment of the present invention.

[0059] As illustrated in FIG. 1, an LED lighting device (100) that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter (1000) and the LED module (2000) comprises: an AC input unit (1100) that receives AC power from an external source; an EMI filter unit (1300) that includes a plurality of filter elements for attenuating noise included in the AC power; a rectification and smoothing unit (1400) that converts the AC power passing through the EMI filter unit (1300) into DC power by rectifying and smoothing it; and an active power factor control unit (1500) that includes a power factor compensation circuit unit (1510) that actively controls the power factor so that the waveform of the input current becomes phase with the waveform of the input voltage in the DC power output from the rectification and smoothing unit (1400). The transformer includes a transformer in which the primary winding section (1610) and the secondary winding section (1620) are electrically isolated, and converts the pulse power applied to the primary winding section (1610) to a predetermined voltage level in conjunction with the switching operation in the active power factor control section (1500), and then outputs it to the secondary winding section (1620); a DC-DC dimming control section (1700) that rectifies the power converted through the transformer section (1600) into DC power and controls the amount of output current output to the LED module (2000) based on a dimming voltage value determined according to the respective temperatures of the converter (1000) and the LED module (2000); and an LED module (2000) that is driven by receiving the output current.

[0061] Specifically, as illustrated in FIG. 1, the LED lighting device (100) of the present invention includes a converter (1000) and an LED module (2000). The converter (1000) corresponds to a configuration that converts alternating current into direct current, as in a known concept. It is not limited to a simple converter (1000) element, but is preferably interpreted as a concept that stably converts an external alternating current power source into direct current power source at the front end of the LED module (2000), such as an SMPS (Switching Mode Power Supply) of an LED lighting fixture, and is equipped with a dimming control function. Additionally, the LED module (2000) includes a light-emitting part (2010) in which a plurality of LED elements are connected in series or parallel and emit light when power is applied.

[0062] The above converter (1000) is characterized by being designed based on a two-stage design. More specifically, the above converter (1000) is configured such that an Active Power Factor Correction CV Controller (APFC CV Controller) (1500) and a DC-DC Dimming Controller (1700) each constitute a single stage. In the case of conventional LED lighting fixtures configured as a single stage, the blinking phenomenon can be completely eliminated, and voltage stress on semiconductor devices can be reduced, thereby improving the durability of the LED lighting fixture.

[0064] More specifically, the converter (1000) includes an AC input section (1100), a surge protection section (1200), an EMI filter section (1300), a rectification and smoothing section (1400), an active power factor control section (1500), a transformer section (1600), and a DC-DC dimming control section (1700). The AC input section (1100) performs an AC input step of receiving AC power from an external source and includes an L-phase power line connection section to which an L-phase power line is connected; an N-phase power line connection section to which an N-phase power line is connected; and a grounding section connected to a ground line. The AC power applied from an external source through the L-phase power line connection section and the N-phase power line connection section is transmitted to the EMI filter section (1300). At this time, preferably, the AC power applied from the outside can be transmitted to the EMI filter unit (1300) via the surge protection unit (1200) as shown in FIG. 1. Further explanation of the surge protection unit (1200) will be provided later in the explanation of FIG. 2.

[0066] The EMI filter unit (1300) performs an EMI filtering step that attenuates noise included in the AC power source using a plurality of filter elements. More specifically, the EMI filter unit (1300) blocks electromagnetic interference (EMI) inside and outside the converter (1000). More specifically, the EMI filter unit (1300) blocks external electromagnetic noise entering through the power line of the LED lighting device (100), thereby preventing internal circuit malfunction of the LED lighting device (100), and performs the role of preventing switching noise generated by switching operations inside the converter (1000) (e.g., performed in the active power factor control unit (1500)) from spreading to the external power line and affecting other electronic devices. The AC power source that has passed through the EMI filter unit (1300) is transmitted to the rectification and smoothing unit (1400).

[0068] The above rectification and smoothing unit (1400) performs a rectification and smoothing step of converting the AC power filtered in the EMI filter step into DC power by rectifying and smoothing it. More specifically, the above rectification and smoothing unit (1400) converts the AC voltage in the form of a sine wave into DC power using a plurality of diode elements. Here, the converted DC power is not a perfect DC power but has a certain ripple, so a process of smoothing it is performed. The smoothing process can be performed using a capacitor, and additional explanation related thereto will be described later in the description of FIG. 3.

[0070] The above active power factor control unit (APFC CV Controller) (1500) performs an active power factor control step in which the waveform of the input current is in phase with the waveform of the input voltage in the DC power supply output by the above rectification and smoothing step. That is, the above active power factor control unit (1500) performs a power factor improvement function that actively increases power efficiency and power quality; and a constant voltage (CV) control function that supplies a stable voltage to the downstream transformer unit (1600) and DC-DC dimming control unit (1700). More specifically, the above active power factor control unit (1500) is characterized by suppressing the phenomenon of power factor reduction or the phenomenon of total harmonic distortion (THD) increase that occurs during the above rectification and smoothing step process. The above active power factor control unit (1500) improves the power factor to be close to 1 (preferably 0.9 or higher) by making the input current waveform almost identical to the input voltage waveform through high-speed switching control using a MOSFET, etc.

[0071] In particular, the active power factor control unit (1500) is characterized by the technical feature of receiving feedback power generated in proportion to the output voltage from the transformer unit (1600) as shown in FIG. 1, generating a switching frequency based on the voltage value of the feedback power, and actively controlling the power factor according to the switching frequency. A more detailed explanation regarding this will be provided in the description of FIGS. 4 to 7. Meanwhile, the power output from the active power factor control unit (1500) corresponds to a pulse power having a constant period through the switching control, and the pulse power is transmitted to the transformer unit (1600).

[0072] The transformer section (1600) performs a transforming step in which it converts the pulse power applied to the primary winding section (1610) to a predetermined voltage level in conjunction with the switching operation in the active power factor control step, and then outputs it to the secondary winding section (1620). More specifically, the transformer section (1600) includes a transformer in which the primary winding section (1610) and the secondary winding section (1620) are electrically isolated, and can perform isolation and voltage conversion functions. Since the primary winding section (1610) and the secondary winding section (1620) are electrically insulated, the high voltage on the primary winding section (1610) side is electrically separated from the low voltage on the secondary winding section side, thereby preventing electric shock accidents to the user, and depending on the winding ratio between the primary winding section (1610) and the secondary winding section (1620), an AC power source can be output by converting the voltage of the pulse power source input to the transformer section (1600). The AC power source output from the transformer section (1600) is transmitted to the DC-DC dimming control section (1700).

[0073] The DC-DC dimming controller (1700) rectifies the power received from the transformer unit (1600) into a DC power source and performs a DC-DC dimming control step that controls the amount of output current output to the LED module (2000) based on a dimming voltage value determined according to the respective temperatures of the converter (1000) and the LED module (2000). More specifically, the DC-DC dimming controller (1700) converts the voltage of the power received from the transformer unit (1600) into a constant voltage (cv) to suit the LED module (2000) and performs a dimming function that controls the brightness of the LED module (2000) by adjusting the amount of output current applied to the LED module (2000).

[0074] In particular, the DC-DC dimming control unit (1700) is characterized by the technical feature of adjusting the amount of output current by considering both the temperature of the converter (1000) and the temperature of the LED module (2000), thereby controlling the brightness of the LED module (2000). In other words, if the temperature of the converter (1000) or the temperature of the LED module (2000) becomes too high, the amount of output current is reduced to lower the temperature, thereby improving the durability and safety of the LED lighting device (100) of the present invention. Obviously, to implement such a function, a temperature measuring unit capable of detecting temperature is provided in each of the converter (1000) and the LED module (2000), and the first temperature measuring unit (3100) provided in the converter (1000) and the temperature measuring unit provided in the LED module (2000) are connected in parallel to each other. A more detailed explanation regarding this will be provided later in the description of Figures 9 to 12.

[0075] As described above, unlike conventional technologies that support a dimming function without considering power factor reduction or harmonic distortion, the LED lighting device (100) of the present invention supports a dimming function that limits the output current by considering the temperature of each of the converter (1000) and the LED module (2000), and is characterized by suppressing power factor reduction and harmonic distortion (THD) increase during the process of limiting the output current. Below, each component of the LED lighting device (100) and the processes performed by those components will be described in detail. At this time, the circuit diagrams shown below illustrate only the minimum components to explain the technical features of the present invention, and may include additional electrical / electronic components in addition to the components disclosed in this specification.

[0077] FIG. 2 schematically illustrates a circuit diagram of an AC input unit (1100), a surge protection unit (1200), and an EMI filter unit (1300) according to one embodiment of the present invention.

[0079] As illustrated in FIG. 2, the LED lighting device (100) comprises an AC input unit (1100) that receives AC power from an external source; a surge protection unit (1200); and an EMI filter unit (1300) that includes a plurality of filter elements for attenuating noise included in the AC power source. The surge protection unit (1200) comprises a varistor that is positioned between the AC input unit (1100) and the EMI filter unit (1300) and can protect the circuit at the downstream end when an overvoltage is introduced through the AC input unit (1100); and a fuse that blocks overcurrent.

[0080] Additionally, the EMI filter section (1300) may further include an X capacitor connected between two AC input lines into which the AC power is input to attenuate differential mode noise; and a Y capacitor connected between the AC input lines and ground to provide a ground path for common mode noise; and may further include a choke section comprising one or more chokes, each having two windings wound on a single core, which can attenuate noise contained in the AC power by canceling out the magnetic field generated by the differential mode current and providing a higher impedance to the common mode current than the impedance of the differential mode current.

[0082] Specifically, the AC input unit (1100) includes, as described above, an L-phase power line connection unit (L in FIG. 2) to which an L-phase power line is connected; an N-phase power line connection unit (N in FIG. 2) to which an N-phase power line is connected; and a grounding unit (FG in FIG. 2) to which a grounding line is connected. The L-phase power line connection unit and the N-phase power line connection unit are connected to the surge protection unit (1200), and the surge protection unit (1200) may include a varistor (VA) capable of protecting the downstream circuit when an overvoltage is introduced through the AC input unit (1100); and a fuse (F) that cuts off overcurrent. As an embodiment of the present invention, additional electrical / electronic components may be included in addition to the varistor and the fuse.

[0083] The AC power input through the AC input section (1100) and the surge protection section (1200) is transmitted to the EMI filter section (1300). As described above, the EMI filter section (1300) performs an EMI filtering step to block electromagnetic interference (EMI) inside and outside the converter (1000). As shown in FIG. 2, the EMI filter section (1300) may include X capacitors (CX1, CX2), Y capacitors (CY1, CY2), and one or more chokes (LF1 to LF5, Line Filter).

[0084] The X capacitor mentioned above refers to a capacitor connected between lines, that is, between the L-phase power line and the N-phase power line, and acts like a fuse to protect the circuit when instantaneous transient voltage, surge, or arc phenomenon occurs between the lines. The Y capacitor mentioned above refers to a capacitor connected between a line and ground, that is, between the N-phase power line and the ground line, and is effective in allowing ripple voltage to flow to ground. The choke is composed of a core made of a magnetic material such as ferrite and a copper wire surrounding the core, and the EMI filter section (1300) can suppress noise of a specific frequency through a choke section including one or more chokes.

[0086] More specifically, the choke section is configured such that when a normal signal flows in a differential mode, that is, when the direction of the current flowing in the L-phase power line and the N-phase power line is opposite to each other, the magnetic field generated by this differential mode current cancels each other out. Through this, in a normal signal, the choke operates as if it has very low resistance, allowing the current to pass through as is.

[0087] Meanwhile, a current mixed with noise, which is introduced from the outside or generated by internal switching, may be introduced into the power line. In the common mode where the current mixed with noise is flowing—that is, when the current flowing in the L-phase power line and the N-phase power line flows in the same direction—the choke section reinforces the magnetic field generated by this common mode current. The reinforced magnetic field acts as a high resistance that obstructs the current mixed with noise, thereby preventing the signal mixed with noise from passing through.

[0088] As described above, the AC power passing through the AC input section (1100), the surge protection section (1200), and the EMI filter section (1300) is transmitted to the rectification and smoothing section (1400), and an explanation thereof will be provided below.

[0090] FIG. 3 schematically illustrates a circuit diagram of a rectification smoothing unit (1400) according to one embodiment of the present invention.

[0092] As illustrated in FIG. 3, the rectifying smoothing unit (1400) includes: a bridge unit that converts the AC power into pulsating DC by connecting four diodes in a bridge form; and a capacitor connected in parallel to the output terminal of the bridge unit, which charges when the pulsating DC rises and discharges when it falls, and reduces the ripple component of the pulsating DC through charging and discharging according to the rise and fall of the pulsating DC.

[0094] Specifically, the bridge section is configured by combining four individual diodes (D1 to D4) in a bridge form to convert AC power into pulsating DC. More specifically, when the waveform of the input AC power is in the positive (+) half-cycle, two specific diodes within the bridge diode are turned on in the forward direction to allow current to flow in one direction, and when the input waveform is in the negative (-) half-cycle, the remaining two diodes are turned on to reverse the direction of the current flowing in the negative (-) direction and output it in the positive (+) direction, thereby performing a rectification process.

[0095] As an embodiment of the present invention, the bridge section may include two capacitors, and the capacitors are connected to the output terminal of the bridge section to perform a smoothing step that removes ripple components included in the pulse DC output from the bridge section and flattens the waveform to be close to DC. According to an embodiment of the present invention, smoothing performance can be improved by configuring each of the two capacitors as capacitors having different characteristics, thereby effectively removing both low-frequency ripple and high-frequency noise.

[0096] Meanwhile, as illustrated in FIG. 3, the bridge section may further include a varistor connected in parallel with the capacitors, which can protect the components located at the downstream end by absorbing excessive surge energy and clamping the voltage when a strong voltage is applied instantaneously due to factors such as lightning strikes or external switching surges.

[0098] FIG. 4 schematically illustrates the internal configuration of an active power factor control unit (1500) according to one embodiment of the present invention, FIG. 5 schematically illustrates the circuit diagram of an active power factor control unit (1500) according to one embodiment of the present invention, FIG. 6 schematically illustrates the connection relationship between each of the internal configurations of an active power factor control unit (1500) according to one embodiment of the present invention, and FIG. 7 schematically illustrates two switching frequencies having different Ton according to one embodiment of the present invention.

[0100] As illustrated in FIGS. 4 to 7, the LED lighting device (100) of the present invention, which suppresses power factor reduction and harmonic distortion increase, includes an active power factor control unit (1500) comprising a power factor compensation circuit unit (1510) that actively controls the power factor so that the waveform of the input current becomes phase with the waveform of the input voltage in the DC power supply output from the rectification smoothing unit (1400).

[0101] The above active power factor control unit (1500) further includes a power factor control unit (1520) including an IC element for controlling the power factor compensation circuit unit (1510); and the power factor control unit (1520) includes a feedback module (1522) that receives feedback power applied through the auxiliary winding unit (1630) of the transformer unit (1600), derives an error value between the feedback voltage of the feedback power and the reference voltage, and amplifies the error value; and a switching frequency generation unit (1521) that generates a switching frequency having a frequency value determined based on the amplified error value and transmits the generated switching frequency to the power factor compensation circuit unit (1510).

[0103] Specifically, conventional power factor compensation circuits perform the role of improving the power factor by correcting the waveform of the input current and the waveform of the input voltage to be as similar as possible, and almost all conventional LED lighting fixtures include such a power factor compensation circuit. Although such conventional power factor compensation circuits maintain a high power factor under specific conditions such as rated output, there was a problem in that when the final output delivered to the LED module (2000) changes dynamically due to protection operation caused by the temperature rise of the LED module (2000); or automatic brightness adjustment according to environmental conditions; the power factor compensation control fails to maintain an optimal state, resulting in a decrease in the power factor and an increase in harmonic distortion.

[0104] In order to solve the aforementioned problems, the present invention discloses an active power factor control unit (1500) capable of dynamically controlling a power factor compensation operation by receiving feedback on the state of the output terminal. More specifically, with reference to FIG. 4, the active power factor control unit (1500) includes a power factor compensation circuit unit (1510) that receives a DC power supply from the rectification smoothing unit (1400) and performs power factor compensation; and a power factor control unit (1520) that controls the same. As shown in FIG. 5, the power factor compensation circuit unit (1510) may include at least one of an inductor, a switching element (e.g., a MOSFET), and a diode, and by receiving a control signal (switching frequency) from the power factor control unit (1520) and switching the switching element on / off at high speed, the waveform of the input current can be controlled and transmitted to the transformer unit (1600) at the subsequent stage.

[0105] Referring to FIG. 5, the power factor control unit (1520) may include an IC element for controlling the power factor compensation circuit unit (1510), and as shown in FIG. 4 and FIG. 6, the power factor control unit (1520) includes a feedback module (1522) for detecting the state of the power output to the LED module (2000); and a switching frequency generation unit (1521) for generating a control signal (switching frequency) based on the detected state.

[0106] The above feedback module (1522) receives feedback power from an auxiliary winding section (1630) provided in a transformer section (1600) connected to the rear end of the active power factor control section (1500). The voltage induced (generated) in the auxiliary winding section (1630) has a characteristic that is proportional to the voltage output from the secondary winding section (1620) of the transformer section (1600), that is, the voltage transmitted to the DC-DC dimming control section (1700).

[0107] Through this, the feedback module (1522) can indirectly determine the voltage output to the LED module (2000) through the voltage value of the feedback power (hereinafter, feedback voltage), and the error detection unit of the feedback module (1522) performs an error detection step of detecting an error value (= reference voltage - feedback voltage) derived by comparing the feedback voltage and the reference voltage, and the error amplification unit of the feedback module (1522) performs an error amplification step of amplifying the error value. The feedback step performed by the feedback module (1522) includes the error detection step and the error amplification step.

[0109] The switching frequency generation unit (1521) performs a switching frequency generation step of generating a switching frequency having a frequency value determined based on an amplified error value. More specifically, the switching frequency generation unit (1521) determines an optimal switching frequency to control the switching element of the power factor compensation circuit unit (1510) based on the amplified error value. Here, with reference to FIG. 6, the Ton (turn-on time) control unit of the switching frequency generation unit (1521) controls the Ton of the switching frequency, and the power factor compensation circuit unit (1510) compensates the power factor of the input power according to the switching frequency.

[0111] FIG. 7(a) illustrates the waveform of a switching frequency when Ton is set long, i.e., when the feedback voltage is low, and FIG. 7(b) illustrates the waveform of a switching frequency when Ton is set short, i.e., when the feedback voltage is high. In other words, a low feedback voltage means that the output voltage is low, and if the output voltage is low, the error value increases, and the switching frequency generator (1521) generates a switching frequency of increased Ton as shown in FIG. 7(a) to transmit more energy. Conversely, a high feedback voltage means that the output voltage is sufficient, and if the output voltage is high, the error value decreases, and the switching frequency generator (1521) generates a switching frequency of decreased Ton as also shown in FIG. 7(b) to transmit less energy.

[0113] FIG. 14 schematically illustrates a graph of a switching frequency according to an amplified error value (amplification error value) according to an embodiment of the present invention. According to the graph shown in FIG. 14, when the amplification error value increases, the maximum frequency value (Fsw max) of the switching frequency increases, and the switching frequency generating unit generates a switching frequency of increased Ton. Conversely, when the amplification error value decreases, the maximum frequency value (Fsw max) of the switching frequency decreases, and the switching frequency generating unit generates a switching frequency of decreased Ton.

[0115] The present invention is characterized by having a loop feedback structure in the order of 'transformer unit (1600) -> feedback module (1522) -> switching frequency generation unit (1521) -> power factor compensation circuit unit (1510)', and through this structure, the active power factor control unit (1500) can recognize load fluctuations at the output terminal in real time and reflect them in the control.

[0116] That is, assuming a situation where the temperature of the LED module (2000) or converter (1000) overheats and the DC-DC dimming control unit (1700) limits (dims) the output current for circuit protection, the process of ‘1) the final output current is reduced, 2) the change in 1) is immediately detected through a change in the feedback voltage generated in the auxiliary winding unit (1630) of the transformer unit (1600), 3) the feedback module (1522) generates a new error value according to the changed feedback voltage, 4) the switching frequency generation unit (1521) determines a new switching frequency optimized for the reduced output current based on the generated error value, 5) the power factor compensation circuit unit (1510) operates according to the changed switching frequency to perform optimal power factor compensation so that the input power required for the reduced output power can be used’ can be performed in the LED lighting device (100) of the present invention.

[0117] Through this, the present invention can significantly suppress the phenomenon in which the power factor decreases or harmonic distortion increases even during output limiting or dimming operations due to temperature rise, by having the active power factor control unit (1500) receive real-time feedback on the state change of the final output stage and dynamically optimize the control parameters. This can provide the effect of maintaining the energy efficiency of the LED lighting device (100) at a high level throughout the overall operating range and greatly improving stability and reliability.

[0119] Meanwhile, as an embodiment of the present invention, the active power factor control unit (1500) may further include a snubber circuit unit (1511), as shown in FIG. 5. A snubber circuit is a circuit for suppressing voltage spikes and high-frequency ringing that occur when a switching element, such as a MOSFET or a diode, is turned off, and can prevent damage to the switching element and reduce the emission of electromagnetic noise (EMI) caused by unnecessary high-frequency vibration (ringing). As shown in FIG. 5, the snubber circuit unit (1511) may include a resistor, a capacitor, and a diode, and as an embodiment of the present invention, when spike energy flows rapidly into the capacitor through the diode, the energy stored in the capacitor is gradually discharged through the resistor, thereby producing the aforementioned effect.

[0121] FIG. 8 schematically illustrates the internal configuration of a transformer unit (1600) according to one embodiment of the present invention, and FIG. 9 schematically illustrates the circuit diagram of a transformer unit (1600) according to one embodiment of the present invention.

[0123] As illustrated in FIGS. 8 and 9, the LED lighting device (100) of the present invention, which suppresses power factor reduction and harmonic distortion increase, comprises a transformer in which a primary winding section (1610) and a secondary winding section (1620) are electrically isolated, and a transformer section (1600) that converts a pulse power applied to the primary winding section (1610) to a predetermined voltage level in conjunction with a switching operation in the active power factor control section (1500) and then outputs it to the secondary winding section (1620); and the transformer section (1600) further comprises an auxiliary winding section (1630) that generates feedback power proportional to the voltage output from the secondary winding section (1620).

[0125] Specifically, with reference to the description of FIG. 1, the transformer unit (1600) efficiently transmits power received from the active power factor control unit (1500) at the front end to the DC-DC dimming control unit (1700) at the rear end, and performs the operation of converting the high voltage applied to the primary winding unit (1610) to the voltage required at the secondary winding unit (1620) end. In addition, it can perform an insulation function to physically separate the circuit on the secondary winding unit (1620) side, which may be touched by a user, and the circuit on the primary winding unit (1610) side, which is connected to an external power grid.

[0126] As illustrated in FIGS. 8 and 9, the primary winding section (1610) is connected to the output of the active power factor control section (1500) as an input terminal of the transformer section (1600). When a pulse power generated by the switching operation of the active power factor control section (1500) is applied to the primary winding section (1610), the current flowing through the winding of the primary winding section (1610) changes, and this change can generate a magnetic flux that changes over time in the core. Through this process, electrical energy on the side of the primary winding section (1610) can be converted into magnetic energy and transmitted to the core.

[0127] The secondary winding section (1620) is connected to the input of the DC-DC dimming control section (1700) as the output terminal of the transformer section (1600). The time-varying magnetic flux generated in the core by the primary winding section (1610) induces an alternating voltage in the secondary winding section (1620) according to the law of electromagnetic induction. The magnitude of the induced voltage is determined by the turns ratio of the primary winding section (1610) and the secondary winding section (1620), and as an embodiment of the present invention, it is generally stepped down to a low level suitable for driving the LED module (2000). The power converted through the secondary winding section (1620) can be transmitted to the DC-DC dimming control section (1700) and used to generate the final driving power (output current).

[0128] As described above, the auxiliary winding section (1630) provides feedback power to the active power factor control section (1500). Since the auxiliary winding section (1630) is affected by the magnetic flux of the same core as the secondary winding section (1620), the voltage induced in the auxiliary winding section (1630) has a proportional relationship with the voltage induced in the secondary winding section (1620), that is, the voltage of the output terminal. The present invention can achieve the effect of monitoring the state of the output voltage in real time without a complex feedback circuit such as a separate optocoupler through the aforementioned transformer section (1600).

[0130] FIG. 10 schematically illustrates the configuration of a temperature sensing module (3000) provided in each of a DC-DC dimming control unit (1700) and an LED module (2000) according to one embodiment of the present invention, FIG. 11 schematically illustrates the process of performing a temperature sensing step according to one embodiment of the present invention, and FIG. 12 schematically illustrates a characteristic graph of an NTC thermistor included in a temperature sensing module (3000) according to one embodiment of the present invention.

[0132] As illustrated in FIGS. 10 to 12, the LED lighting device (100) of the present invention, which suppresses power factor reduction and harmonic distortion increase, comprises: a DC-DC dimming control unit (1700) that rectifies power converted through the transformer unit (1600) into DC power and controls the amount of output current output to the LED module (2000) based on a dimming voltage value determined according to the respective temperatures of the converter (1000) and the LED module (2000); and an LED module (2000) that is driven by receiving the output current.

[0133] Additionally, the LED lighting device (100) further includes a temperature sensing module (3000), and the temperature sensing module (3000) includes a first temperature measuring unit (3100) provided in the DC-DC dimming control unit (1700); and a second temperature measuring unit (3200) provided in the LED module (2000), wherein the first temperature measuring unit (3100) and the second temperature measuring unit (3200) are connected in parallel with each other.

[0134] Additionally, the first temperature measuring unit (3100) includes a first NTC thermistor whose resistance value decreases as the temperature rises, the second temperature measuring unit (3200) includes a second NTC thermistor whose resistance value decreases as the temperature rises, and the temperature sensing module (3000) determines the temperature of the LED lighting device (100) based on the parallel sum of the resistance value of the first NTC thermistor and the resistance value of the second NTC thermistor.

[0135] Additionally, the DC-DC dimming control unit (1700) performs the steps of: deriving a dimming voltage value according to the temperature determined by the temperature sensing module (3000); determining a current value of the output current based on the dimming voltage value; and transmitting the output current corresponding to the determined current value to the LED module (2000); wherein the output current is determined in proportion to the dimming voltage value, and the current value of the output current is greater than or equal to a preset minimum current value and less than or equal to a preset maximum current value.

[0137] Specifically, with reference to FIG. 10, the DC-DC dimming control unit (1700) may include a rectifier (1710) that converts AC power received from the secondary winding unit (1620) into DC power, and the DC power converted by the rectifier (1710) is applied to the light-emitting unit (2010) of the LED module (2000). The light-emitting unit (2010) corresponds to a configuration in which a plurality of LED elements are connected in series and / or parallel, and can emit light using the DC power applied through the rectifier (1710) as a driving power. In particular, the brightness of the light emitted from the light-emitting unit (2010) can be determined according to the amount of DC power applied, that is, the amount of output current output from the DC-DC dimming control unit (1700).

[0138] Meanwhile, as illustrated in FIG. 10, the present invention is characterized by the technical feature of simultaneously considering the temperatures of the converter (1000) and the LED module (2000). More specifically, the temperature sensing module (3000) of the present invention includes a first temperature measuring unit (3100) provided in the converter (1000); and a second temperature measuring unit (3200) provided in the LED module (2000). The first temperature measuring unit (3100) is preferably provided in the DC-DC dimming control unit (1700), but according to one embodiment of the present invention, it may be provided in any part of the converter (1000).

[0139] Although there is a technology that discloses a configuration for measuring temperature in conventional LED lighting fixtures and protecting the circuit based on the measured temperature, most of these conventional technologies only measure the temperature of either the converter (1000) or the LED module (2000), and in such cases, they have limitations in that they cannot completely protect the circuit of the lighting fixture from overheating. Meanwhile, recently, technologies for measuring temperature in each of the converter (1000) and the LED module (2000) have been disclosed, but in such cases, there are problems such as the circuit becoming complex and costs increasing, such as using multi-channel input or multiple comparator circuits at the control unit (MCU) stage. The present invention has overcome the aforementioned problems through the details described below.

[0140] The first temperature measuring unit (3100) includes a first NTC thermistor whose resistance value decreases when the temperature inside the converter (1000) rises, and the second temperature measuring unit (3200) includes a second NTC thermistor whose resistance value decreases when the temperature inside the LED module (2000), particularly the LED module (2000), rises. FIG. 12 illustrates the temperature-resistance value characteristic graph of the first temperature measuring unit (3100) and the second temperature measuring unit (3200). Here, as shown in FIG. 11, the first temperature measuring unit (3100) and the second temperature measuring unit (3200) are connected in parallel to each other, which is a technical feature.

[0141] More specifically, two temperature measuring units (3100 and 3200) connected in parallel can form a single composite resistance value (parallel sum). The composite resistance value has the characteristic of becoming smaller than the smallest value among the individual resistances when the resistors are connected in parallel. That is, if the temperature rises in either the converter (1000) or the LED module (2000) and the NTC resistance value of the corresponding temperature measuring unit decreases, the total composite resistance value decreases significantly. The DC-DC dimming control unit (1700) can derive a dimming voltage value by converting the change in the composite resistance value into a voltage divider circuit, etc., as shown in FIG. 11.

[0142] The DC-DC dimming control unit (1700) determines the magnitude of the output current output to the LED module (2000) based on the derived dimming voltage value. FIG. 13 schematically illustrates an output current graph according to a dimming voltage value according to an embodiment of the present invention, and the DC-DC dimming control unit (1700) can determine the magnitude of the output current based on the output current graph. The first voltage value shown in FIG. 13 represents the minimum value of the dimming voltage value, and the second voltage value shown in FIG. 13 represents the maximum value of the dimming voltage value. The minimum / maximum value of the dimming voltage value and the minimum / maximum current value shown in FIG. 13 can be determined by the specifications of the components constituting the LED lighting device (100) of the present invention.

[0144] According to one embodiment of the present invention, by detecting the temperatures of both the converter and the LED module to precisely determine the overall thermal state of the system and responding preemptively thereto, it is possible to achieve the effect of significantly improving the stability and reliability of the LED lighting device.

[0145] According to one embodiment of the present invention, since the output current is controlled by detecting not only the temperature rise of the LED module but also the overheating of the converter itself, it is possible to achieve the effect of preventing deterioration and damage to the converter components even in a sealed environment.

[0146] According to one embodiment of the present invention, the performance of the power factor compensation circuit is prevented due to overheating of the converter, and the effect of continuously maintaining a high power factor is achieved by stably controlling the input current waveform.

[0147] According to one embodiment of the present invention, the effect of suppressing electromagnetic interference (EMI) and parasitic oscillations can be achieved by eliminating switch noise.

[0148] According to one embodiment of the present invention, by effectively managing thermal stress in the system, the lifespan of key components within the LED element and converter can be extended, thereby improving the overall durability of the lighting device.

[0149] According to one embodiment of the present invention, by comprehensively reflecting temperature information from two points through a simple circuit configuration in which two temperature measuring units (NTC thermistors) are connected in parallel, it is possible to achieve the effect of implementing an efficient overheat protection function without complex control logic or an additional microcontroller.

[0150] According to one embodiment of the present invention, when overheating is detected, the output current is gradually reduced rather than simply cutting off the power, so the effect of stably protecting the lighting device without causing inconvenience to the user can be achieved.

[0151] According to one embodiment of the present invention, by maintaining stable power characteristics (power factor, harmonics) even under abnormal operating conditions such as overheating, it is possible to achieve the effect of being flexibly applied to various lighting environments requiring high quality and high reliability.

[0152] According to one embodiment of the present invention, even when the output current decreases due to temperature, the stability of the compensation loop in the active power factor control unit is secured, thereby preventing malfunction of the controller (IC) and thereby enabling the effect of extending the lifespan of the LED lighting device.

[0153] According to one embodiment of the present invention, by automatically adjusting the switching frequency, the effect of increasing efficiency during light load can be achieved.

[0155] Although the embodiments have been described above with reference to limited examples and drawings, those skilled in the art can make various modifications and variations from the description above. For example, suitable results can be achieved even if the described techniques are performed in a different order than described, and / or the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0156] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below.

Claims

Claim 1 An LED lighting device that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter and the LED module, comprising: an AC input section receiving AC power from an external source; an EMI filter section including a plurality of filter elements for attenuating noise included in the AC power; a rectification and smoothing section converting the AC power passing through the EMI filter section into DC power by rectifying and smoothing it; a power factor compensation circuit section that actively controls the power factor so that the waveform of the input current becomes in phase with the waveform of the input voltage in the DC power output from the rectification and smoothing section; and a power factor controller section including an IC element for controlling the power factor compensation circuit section; an active power factor control section; and a transformer in which the primary winding section and the secondary winding section are electrically isolated. and an auxiliary winding section that generates feedback power proportional to the voltage output from the secondary winding section; a transformer section that converts the pulse power applied to the primary winding section to a predetermined voltage level in conjunction with the switching operation of the active power factor control section and outputs it to the secondary winding section; a DC-DC dimming control section that rectifies the power converted through the transformer section into DC power and controls the amount of output current output to the LED module based on a dimming voltage value determined according to the respective temperatures of the converter and the LED module; an LED module driven by receiving the output current; and a first temperature measuring section including a first NTC thermistor provided in the DC-DC dimming control section, which is connected in parallel with each other. A temperature sensing module comprising: a second temperature measuring unit including a second NTC thermistor provided in the LED module; and the power factor controller unit comprises a feedback module that receives feedback power applied through the auxiliary winding unit, derives an error value between the feedback voltage of the feedback power and a reference voltage, and amplifies the error value.An LED lighting device comprising: a switching frequency generating unit that generates a switching frequency for controlling the turn-on time of a switching element within the power factor compensation circuit based on an amplified error value, and transmits the generated switching frequency to the power factor compensation circuit; wherein the temperature sensing module determines the temperature of the LED lighting device based on the parallel sum of the resistance value of the first NTC thermistor and the resistance value of the second NTC thermistor. Claim 2 The LED lighting device according to claim 1 further comprises a surge protection unit including: a varistor disposed between the AC input unit and the EMI filter unit and capable of protecting a downstream circuit when an overvoltage is introduced through the AC input unit; and a fuse that blocks overcurrent. Claim 3 An LED lighting device according to claim 1, wherein the EMI filter section comprises: an X capacitor connected between two AC input lines into which the AC power is input to attenuate differential mode noise; and a Y capacitor connected between the AC input lines and ground to provide a ground path for common mode noise. Claim 4 The LED lighting device according to claim 3, wherein the EMI filter section further comprises a choke section including one or more chokes, wherein two windings are wound on a single core, and the choke section is capable of canceling out the magnetic field generated by the differential mode current and providing a common mode current with an impedance higher than that of the differential mode current to attenuate noise included in the AC power source. Claim 5 An LED lighting device according to claim 1, wherein the rectifying smoothing unit comprises: a bridge unit that converts the AC power source into pulsating DC by connecting four diodes in a bridge form; and a capacitor connected in parallel to the output terminal of the bridge unit, which charges when the pulsating DC rises and discharges when it falls, and reduces the ripple component of the pulsating DC through charging and discharging according to the rise and fall of the pulsating DC. Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 An LED lighting device according to claim 1, wherein the DC-DC dimming control unit performs the steps of: deriving a dimming voltage value according to a temperature determined by the temperature sensing module; determining a current value of the output current based on the dimming voltage value; and transmitting the output current corresponding to the determined current value to the LED module; wherein the output current is determined in proportion to the dimming voltage value, and the current value of the output current is greater than or equal to a preset minimum current value and less than or equal to a preset maximum current value. Claim 12 A driving method for an LED lighting device that suppresses power factor reduction and harmonic distortion increase by varying the output current based on the temperature sensed in each of the converter and the LED module, comprising: an AC input step receiving AC power from an external source; an EMI filter step that attenuates noise included in the AC power using a plurality of filter elements; a rectification and smoothing step that rectifies and smooths the AC power filtered in the EMI filter step and converts it into DC power; an active power factor control step that actively controls the power factor of the DC power output by the rectification and smoothing step so that the waveform of the input current becomes in phase with the waveform of the input voltage; and a transformer section including a transformer and an auxiliary winding section in which the primary winding section and the secondary winding section are electrically isolated, wherein the pulse power applied to the primary winding section is converted to a predetermined voltage level in conjunction with the switching operation in the active power factor control step, outputs to the secondary winding section, and through the auxiliary winding section, the A transforming step that generates feedback power proportional to the voltage output from the secondary winding section; a DC-DC dimming control step that rectifies the power converted through the transforming step into DC power and controls the amount of output current output to the LED module based on a dimming voltage value determined according to the respective temperatures of the converter and the LED module; and a first temperature measuring section including a first NTC thermistor provided in a DC-DC dimming control section where the DC-DC dimming control step is performed, which is connected in parallel with each other. A temperature sensing step performed in a temperature sensing module comprising: a second temperature measuring unit including a second NTC thermistor provided in the LED module; wherein the LED module included in the LED lighting device is driven by receiving an output current, and the active power factor control step includes a power factor control step that actively controls the power factor using an IC element; and the power factor control step includes a feedback step that receives feedback power applied through the auxiliary winding unit, derives an error value between the feedback voltage of the feedback power and a reference voltage, and amplifies the error value.A driving method for an LED lighting device comprising: a switching frequency generation step that generates a switching frequency for controlling the turn-on time of a switching element in a power factor compensation circuit, wherein the active power factor control step is performed based on an amplified error value; wherein the power factor control step actively controls the power factor based on the generated switching frequency, and the temperature sensing step determines the temperature of the LED lighting device based on the parallel sum of the resistance value of the first NTC thermistor and the resistance value of the second NTC thermistor. Claim 13 The driving method of claim 12, wherein the driving method of the LED lighting device further comprises a surge protection step capable of protecting a subsequent circuit when an overvoltage is introduced in the AC input step by applying an AC power applied through the AC input step to a varistor and a fuse, and wherein the AC power output after the surge protection step is transmitted to the filter element for the EMI filter step. Claim 14 A method for driving an LED lighting device according to claim 12, wherein the plurality of filter elements comprises: an X capacitor connected between two AC input lines into which the AC power is input; and a Y capacitor each connected between the AC input line and ground to provide a ground path for common mode noise; and the EMI filter step comprises: a step of attenuating differential mode noise through the X capacitor; and a step of attenuating common mode noise through the Y capacitor. Claim 15 A driving method for an LED lighting device according to claim 14, wherein the plurality of filter elements further comprise a choke section including one or more chokes, wherein two windings are wound on a single core, and the choke section is capable of canceling out the magnetic field generated by the differential mode current and providing a common mode current with an impedance higher than that of the differential mode current to attenuate noise included in the AC power source. Claim 16 A driving method for an LED lighting device according to claim 12, wherein the rectification and smoothing step comprises: a step of converting the AC power source into a pulsating DC by means of a bridge portion in which four diodes are connected in a bridge form; and a step of reducing the ripple component of the pulsating DC by means of a capacitor connected in parallel to the output terminal of the bridge portion, by charging the capacitor when the pulsating DC rises and discharging the capacitor when the pulsating DC falls. Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 A driving method for an LED lighting device according to claim 12, wherein the DC-DC dimming control step comprises: a step of deriving a dimming voltage value according to a temperature determined by the temperature sensing module; a step of determining a current value of the output current based on the dimming voltage value; and a step of transmitting the output current corresponding to the determined current value to the LED module; wherein the output current is determined in proportion to the dimming voltage value, and the current value of the output current corresponds to a preset minimum current value or greater and a preset maximum current value or less.

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