The LED control device not only provides current to make the LED work normally and reliably, but also is compatible with various dimming control systems to achieve energy saving and scene lighting. If the function and reliability of the LED control unit cannot be guaranteed, this will become a limitation and short board that limits the performance of the LED. Like LEDs, LED control devices are new things, there are still many problems to be solved, and many new technologies are introduced into new products. The standards of products are not perfect, which leads to a dazzling array of LED control devices. Mixed fish.
This paper analyzes the characteristics and trends of LED control devices by comparing the difference between LED control devices and traditional control devices.
size
Traditional control devices (such as fluorescent ballasts, HIT ballasts) have undergone a relatively long period of development. Because its core technology is still in the hands of several large lighting companies, they have reached a series of agreements and established some standards. In the case of using these conventional control devices, it is found that the conventional control devices of these enterprises are not only almost the same in size, but also almost identical in the positioning size, and even the input and output terminals are identical. This has the advantage that not only can the luminaire manufacturer have more options for use, but it can also be easily replaced by the user.
The LED control device has no similar regulations so far. LED lighting devices have such a trend as LED lighting products are moving toward miniaturization and thinning. However, it results in a control device that may not be able to have the same positioning to be replaced at will. In order to increase the selectivity, it is necessary to try more positioning in the design, and also bring challenges to the management of inventory and delivery. Of course, there is still a product trend. In order to replace the traditional fluorescent lamp, the size of the LED control device is designed to be the same as the fluorescent lamp ballast.
As LED light sources begin to have a modular trend, such as the light engine needs to comply with the ZHAGA standard, the size of the LED drive power supply will be the next generation standardization trend. The uniform size of the LED control unit facilitates interchangeability and warehousing management, but it is not conducive to product innovation. We need to find a balance between standardization and innovation.
power
For conventional control devices, the model number is determined by the power of the light source that can be controlled. Taking OSRAM's electronic ballast products as an example, for the fluorescent lamp ballast QTP51x28, we can easily know that it can control 28W fluorescent lamps; similarly, for the HIT ballast PTi35/220-240, we also know It can control the 35W HIT. Of course, with the development of technology, multi-power ballasts have also been introduced to the market, enabling them to simultaneously drive multiple power sources. But in any case, for traditional control devices, we only need to know the power of the light source, and then we can find the right ballast according to the model.
But this is not the case with LED control devices. For single-particle LEDs, it is often necessary to make the light source we need through a combination of series and parallel. The difference in combination leads to different power and driving voltage. For increasingly popular COB packaged LEDs, different drive voltages and currents can result in different power. This makes it impossible to simply determine whether the LED control unit can be used with the LED by a parameter such as power.
We need to consider multiple factors such as drive current, voltage range, drive power, etc. to fully measure whether we can drive our LEDs (Figure 1). According to the voltage range, we can see that it is generally necessary to bring enough load to work properly, which makes the LED driver power supply not flexible enough in the project.
Although the choice of LED control device has brought us some indirectness, we may need professionals to help us choose the model. On the other hand, we no longer have a light source, maybe an electrical device, like a traditional control device. Several light sources are used to spread the cost of the drive to the light source.
In order to better reflect the advantages of scale cost, LED control devices tend to develop in the direction of high power, and the installation may not be installed with the lamps, but installed in the electrical box. Choosing the right LED control device is actually choosing the right working point according to the LED to be driven (Fig. 2). Whether it is an LED lamp or multiple LED lamps, in addition to the power, we must also consider the output voltage and output current already mentioned. And the load, efficiency, power factor, operating temperature, etc. mentioned below, this is a systematic work.
Voltage and number of connections and connection distance
For conventional control devices, the rated voltage is AC mains, and its general design has a wide voltage range, and its connection distance is generally not limited by the voltage drop. The number of connections placed depends mainly on the current capacity of the wire cross section, the connection terminals, and the like.
For the LED drive control device, in addition to the input voltage is AC mains, many of the drives are low-voltage DC inputs, and the input voltage range is relatively small. The connection distance mainly depends on the voltage drop on the line. Since such a control device generally requires a power transformer at the front end, the number of connections depends mainly on the capacity of the power source.
We need to understand that the longest distance traveled by LED luminaires is critical for engineering applications, especially for large projects. In the early electrical design, the correct calculation can save costs, ensure the consistency of light output and the stability of product work (Figure 3).
Because of engineering needs, we will estimate the maximum length Lc of the wire by simple calculation.
According to Ohm's law and the law of resistance, it can be inferred that the length L of the wire is
In the formula, U is the voltage; S is the cross-sectional area of ​​the wire; I is the current, and Ï is the resistivity.
According to the actual possible lamp line of Figure 4, set the following parameters:
Δx—the allowable voltage drop between the power supply output and the minimum operating voltage of the product, ie the voltage drop across the main line;
Sc - the cross-sectional area of ​​the wire used;
0.0174 - resistivity of copper (Ω·mm2/m) (at 20 ° C);
Np - the maximum number of lamps that the power supply can drive;
I - The maximum input current of the luminaire.
Since the lamps are connected in parallel, the total current is the sum of the currents of the lamps, that is, Np×I.
Bring the above values ​​into the formula (1), the total length of the wire is
Considering that the total length of the wire includes the entire loop, and the maximum length of the wire Lc should be half of this loop, it can be calculated by the following formula:
Formula (3) is a general formula, but when further accurate calculations are made, especially when the wire of a single luminaire needs to be long enough, in addition to the pressure drop generated on the main line, the pressure drop should also be calculated on the partial branch line L1 of the luminaire. The sum of the pressure drop and the pressure drop across the spur is the total pressure drop. Suppose the pressure drop on the branch line is Δy. According to formula (3), the pressure drop on the main line is
Length of the branch line:
The pressure drop on the branch line is
Where: Δy is the allowable pressure drop of a single product of the branch line; S1 is the cross-sectional area of ​​the wire used for a single product.
The total pressure drop is the sum of equation (4) and equation (5), ie
Equation (6) is an accurate calculation of the values ​​between various elements. Of course, in practical applications, other practical restrictions must be further considered. For example, the control device with DMX has a signal line limit of only 100 m; and there is a limitation of the power supply capacity, and the number of lamps actually available is limited. Since the calculation is not particularly convenient, in practical applications we often give simple charts or formulas for the user to use.
Multiple configurations
As described above, the conventional control device generally has a product corresponding to a light source, and even if the fluorescent lamp ballast can be combined with a plurality of fluorescent tubes, it can be realized by its own hardware. LED control devices are generally divided into constant current drive and constant voltage drive.
Constant voltage driving generally has 12V, 24V, 48V, etc., constant current driving generally has 200mA, 350mA, 700mA, 1000mA and so on. In order to facilitate various applications, the trend of LED control devices is no longer a single voltage or current, but can provide a variety of voltage or current combinations, although it will increase part of the cost, but can provide more applications, while reducing the cost of storage. . Ways to change the configuration mainstream are resistors, DIP switches, and programmers.
Secondly, an LED control device may include various control protocols, such as 1~10V, DALI, PushL, etc., and is also applicable to various power grid environments. Basically, one control is in hand, and all applications are not flawed. This is a tradition. The control device can't imagine it.
Of course, multiple configurations are also a challenge for the design of the control unit, and each configuration must balance safety, performance, and EMC. According to the idea of ​​the traditional control device, according to the requirements of the user, the LED lamp manufacturer generally only tests the product with the highest power, but it is not known that the configuration change will cause other changes.
In actual tests, often encounter unqualified conditions, especially EMC, often need to be modified externally. When a different current is configured with a resistor or the like, it tends to cause a change in the harmonic current. A change in the load affects the power factor and affects the harmonic current, which may cause the test to fail (Fig. 5 below).
Furthermore, LED control devices have different efficiencies for different loads, often with low efficiency at low loads, resulting in a large amount of energy being consumed on critical electrical components. It is possible that the temperature at this time is the limit temperature (Figure 6 below). ). Due to the need to balance various performance requirements, each configuration may cause different problems, resulting in different possible solutions. This is bound to define the drawings and BOM of each solution in the design process, which brings design and development work. huge challenge. This also requires LED control manufacturers not only to manufacture such products, but also to carry out a large number of test verification work to reduce the trouble in the application process.
The form of LED is generally a single particle, and even if its luminous efficiency is continuously increasing to a level of 100 lm/W or more, the amount of light emitted by a single particle is still limited. When a suitable luminous flux is required according to the lighting requirements, a combination of a plurality of particles is often required to achieve such a light requirement. For example, some high-powered floodlights , street lamps, downlights, and the like require a combination of a plurality of particles. In addition, for linear lamps that are widely used in buildings, it is far from impossible to achieve this effect by relying on one LED.
It is difficult for us to redesign different numbers of LED boards to make products for different applications. This is not economical for lighting companies, whether it is for design, manufacturing, purchasing or warehousing. In the manufacture of such a product with a relatively large number of LEDs, in order to replace the maintenance, to make the production easy and efficient, and to give full play to the scale cost advantage in practical applications, especially to facilitate the combination of LEDs to achieve ever-changing applications, we will LED Make the smallest unit we need, the module.
Through the increase, decrease and change of modules, we can produce products that can be applied to different occasions. This is the trend of designing and manufacturing LED lamps. With the improvement of the standardization of LED circuit boards, the scale and generalization of products will be effectively realized. The required lamps can be assembled by arranging and combining various standard components. This method is beneficial to improve the quality control level of the industry and is suitable for Large-scale industrialization. This requires the LED control device to cooperate with the modularization of the LED, to output the electrical parameters required for various applications, and to achieve the economical and modularization of the LED control device.
For example, a company produces LED linear lamps, which are available in 0.5m, 1m, and 1.5m sizes depending on the length. The number of LEDs for each specification is 11, 22 and 33. When a circuit board with a length of 0.5 m and 11 LED particles is selected for modular production, the corresponding linear lamps of different lengths need only one, two or three modules assembled. This eliminates the need to separately develop 22-particle and 33-particle LED boards, which is time consuming and costly.
The modularization trend of LEDs has led to the trend of modularization of LED control devices. Taking the above products as an example, if I choose an LED control device that can drive 11 0.5m LED circuit boards, I only need to use 2 or 3 identical LED control devices to drive 1m or 1.5m products.
The scale of the LED control device is obviously able to control the volume of the product to ensure the light and thin LED lighting, to ensure that SELV helps the product to be safe, and to help improve the performance of the product. We assume that the LED's driving voltage is 3V. If only 11 particles need to be driven, the driving voltage is 33V. However, if we want to drive 22 or 33 particles, the driving voltage will reach 66V and 99V. The higher the driving voltage, the higher the manufacturing requirements of the LED control device, which inevitably increases the manufacturing cost, volume, performance, safety and other factors.
Of course, if an LED luminaire product may use several LED control devices at the same time, the LED control device requirements not only require multiple choices in performance to adapt to different module combinations, but secondly, reliability and safety cannot be exceeded. Reduced by multiple control devices. Because the size of the LED control unit cannot be changed, implementing various configurations in the same size is also a challenge for LED control manufacturers.
combination
The main function of the control unit is to convert the input power to the voltage or current at which the light source operates normally. The input power of the traditional control device is generally AC mains, and the input of the LED control device can be AC ​​mains or DC power. Thus, the drive of the LED can also be achieved by a combination of various control devices without a suitable single LED control device. However, traditional control devices cannot implement such combined applications (Fig. 7 below).
The main benefits of this are:
1) In some special safety applications, such as eaves, swimming pools, important political buildings, etc., the main part of the lamp is SELV to ensure the safety of the building and to protect the safety of the user.
2) In order to achieve various application requirements, it is only necessary to design the DC conversion part to increase the amount of power supply, which can greatly reduce the cost and avoid the need to select a special adapter controller for each application.
3) It can also adapt to the volume of various LED lamps, so that the products can adapt to various harsh installation applications. In order to achieve a more beautiful design, the LED driver power supply is often removed from the product. And reduce the impact of heat on the LED.
However, the problem that comes with it is that there are too many control devices, the reliability is poor, and the volume is large. Various controls directly require a reliable connection. Once a certain link is wrong, the whole system will have problems.
Indoor and outdoor applications
Due to the energy saving and color characteristics of LEDs, LEDs are first used in outdoor lighting applications such as street lights, linear lights and buried lights. These types of lamps often have strict water and dust resistance requirements. In practical applications, since the control device is a short board of the lighting system, the lamp is often separated from the control device in consideration of the convenience of maintenance and the need for a safe low voltage in some special occasions. This requires the LED control unit to have the same level of protection as the luminaire. This is also the market we will see a lot of LED control devices with IP ratings. In engineering, LED recessed luminaires are often separated from the lamp body, which also has a large demand for stand-alone LED control devices. These are market characteristics that are significantly different from traditional control devices.
A large number of outdoor applications also require LED control devices to adapt to various extreme temperature conditions, which is a great test for the selection of components. Since most of the energy of LED lamps is converted into heat, the heat dissipation capability will directly affect the life of the LEDs, and thus the life of the LED lamp system. In such a relatively high temperature environment, as the temperature increases, the load capacity of the LED control device also decreases, and the professional manufacturer will give the derating curve of the control device. In addition, in outdoor applications, LED control devices should also consider lightning surge requirements (Figure 8 below).
Conclusion
LED control devices are becoming more and more recognized as a key part of LED lamps. In addition to the great difference between the design principle and the traditional control device, people gradually find that the original knowledge of the control device cannot be applied to the LED control device. In practical applications, we should pay close attention to the development trend of the technicalization of LED control devices, and we must have a correct understanding so that we can really use it. Similarly, only by recognizing the trends in the application can we guide our companies and designers to design the LED controls that are really needed for LED luminaire manufacturers.
This paper analyzes the characteristics and trends of LED control devices by comparing the difference between LED control devices and traditional control devices.
size
Traditional control devices (such as fluorescent ballasts, HIT ballasts) have undergone a relatively long period of development. Because its core technology is still in the hands of several large lighting companies, they have reached a series of agreements and established some standards. In the case of using these conventional control devices, it is found that the conventional control devices of these enterprises are not only almost the same in size, but also almost identical in the positioning size, and even the input and output terminals are identical. This has the advantage that not only can the luminaire manufacturer have more options for use, but it can also be easily replaced by the user.
The LED control device has no similar regulations so far. LED lighting devices have such a trend as LED lighting products are moving toward miniaturization and thinning. However, it results in a control device that may not be able to have the same positioning to be replaced at will. In order to increase the selectivity, it is necessary to try more positioning in the design, and also bring challenges to the management of inventory and delivery. Of course, there is still a product trend. In order to replace the traditional fluorescent lamp, the size of the LED control device is designed to be the same as the fluorescent lamp ballast.
As LED light sources begin to have a modular trend, such as the light engine needs to comply with the ZHAGA standard, the size of the LED drive power supply will be the next generation standardization trend. The uniform size of the LED control unit facilitates interchangeability and warehousing management, but it is not conducive to product innovation. We need to find a balance between standardization and innovation.
power
For conventional control devices, the model number is determined by the power of the light source that can be controlled. Taking OSRAM's electronic ballast products as an example, for the fluorescent lamp ballast QTP51x28, we can easily know that it can control 28W fluorescent lamps; similarly, for the HIT ballast PTi35/220-240, we also know It can control the 35W HIT. Of course, with the development of technology, multi-power ballasts have also been introduced to the market, enabling them to simultaneously drive multiple power sources. But in any case, for traditional control devices, we only need to know the power of the light source, and then we can find the right ballast according to the model.
But this is not the case with LED control devices. For single-particle LEDs, it is often necessary to make the light source we need through a combination of series and parallel. The difference in combination leads to different power and driving voltage. For increasingly popular COB packaged LEDs, different drive voltages and currents can result in different power. This makes it impossible to simply determine whether the LED control unit can be used with the LED by a parameter such as power.
We need to consider multiple factors such as drive current, voltage range, drive power, etc. to fully measure whether we can drive our LEDs (Figure 1). According to the voltage range, we can see that it is generally necessary to bring enough load to work properly, which makes the LED driver power supply not flexible enough in the project.
Although the choice of LED control device has brought us some indirectness, we may need professionals to help us choose the model. On the other hand, we no longer have a light source, maybe an electrical device, like a traditional control device. Several light sources are used to spread the cost of the drive to the light source.
In order to better reflect the advantages of scale cost, LED control devices tend to develop in the direction of high power, and the installation may not be installed with the lamps, but installed in the electrical box. Choosing the right LED control device is actually choosing the right working point according to the LED to be driven (Fig. 2). Whether it is an LED lamp or multiple LED lamps, in addition to the power, we must also consider the output voltage and output current already mentioned. And the load, efficiency, power factor, operating temperature, etc. mentioned below, this is a systematic work.
Voltage and number of connections and connection distance
For conventional control devices, the rated voltage is AC mains, and its general design has a wide voltage range, and its connection distance is generally not limited by the voltage drop. The number of connections placed depends mainly on the current capacity of the wire cross section, the connection terminals, and the like.
For the LED drive control device, in addition to the input voltage is AC mains, many of the drives are low-voltage DC inputs, and the input voltage range is relatively small. The connection distance mainly depends on the voltage drop on the line. Since such a control device generally requires a power transformer at the front end, the number of connections depends mainly on the capacity of the power source.
We need to understand that the longest distance traveled by LED luminaires is critical for engineering applications, especially for large projects. In the early electrical design, the correct calculation can save costs, ensure the consistency of light output and the stability of product work (Figure 3).
Because of engineering needs, we will estimate the maximum length Lc of the wire by simple calculation.
According to Ohm's law and the law of resistance, it can be inferred that the length L of the wire is
In the formula, U is the voltage; S is the cross-sectional area of ​​the wire; I is the current, and Ï is the resistivity.
According to the actual possible lamp line of Figure 4, set the following parameters:
Δx—the allowable voltage drop between the power supply output and the minimum operating voltage of the product, ie the voltage drop across the main line;
Sc - the cross-sectional area of ​​the wire used;
0.0174 - resistivity of copper (Ω·mm2/m) (at 20 ° C);
Np - the maximum number of lamps that the power supply can drive;
I - The maximum input current of the luminaire.
Since the lamps are connected in parallel, the total current is the sum of the currents of the lamps, that is, Np×I.
Bring the above values ​​into the formula (1), the total length of the wire is
Considering that the total length of the wire includes the entire loop, and the maximum length of the wire Lc should be half of this loop, it can be calculated by the following formula:
Formula (3) is a general formula, but when further accurate calculations are made, especially when the wire of a single luminaire needs to be long enough, in addition to the pressure drop generated on the main line, the pressure drop should also be calculated on the partial branch line L1 of the luminaire. The sum of the pressure drop and the pressure drop across the spur is the total pressure drop. Suppose the pressure drop on the branch line is Δy. According to formula (3), the pressure drop on the main line is
Length of the branch line:
The pressure drop on the branch line is
Where: Δy is the allowable pressure drop of a single product of the branch line; S1 is the cross-sectional area of ​​the wire used for a single product.
The total pressure drop is the sum of equation (4) and equation (5), ie
Equation (6) is an accurate calculation of the values ​​between various elements. Of course, in practical applications, other practical restrictions must be further considered. For example, the control device with DMX has a signal line limit of only 100 m; and there is a limitation of the power supply capacity, and the number of lamps actually available is limited. Since the calculation is not particularly convenient, in practical applications we often give simple charts or formulas for the user to use.
Multiple configurations
As described above, the conventional control device generally has a product corresponding to a light source, and even if the fluorescent lamp ballast can be combined with a plurality of fluorescent tubes, it can be realized by its own hardware. LED control devices are generally divided into constant current drive and constant voltage drive.
Constant voltage driving generally has 12V, 24V, 48V, etc., constant current driving generally has 200mA, 350mA, 700mA, 1000mA and so on. In order to facilitate various applications, the trend of LED control devices is no longer a single voltage or current, but can provide a variety of voltage or current combinations, although it will increase part of the cost, but can provide more applications, while reducing the cost of storage. . Ways to change the configuration mainstream are resistors, DIP switches, and programmers.
Secondly, an LED control device may include various control protocols, such as 1~10V, DALI, PushL, etc., and is also applicable to various power grid environments. Basically, one control is in hand, and all applications are not flawed. This is a tradition. The control device can't imagine it.
Of course, multiple configurations are also a challenge for the design of the control unit, and each configuration must balance safety, performance, and EMC. According to the idea of ​​the traditional control device, according to the requirements of the user, the LED lamp manufacturer generally only tests the product with the highest power, but it is not known that the configuration change will cause other changes.
In actual tests, often encounter unqualified conditions, especially EMC, often need to be modified externally. When a different current is configured with a resistor or the like, it tends to cause a change in the harmonic current. A change in the load affects the power factor and affects the harmonic current, which may cause the test to fail (Fig. 5 below).
Furthermore, LED control devices have different efficiencies for different loads, often with low efficiency at low loads, resulting in a large amount of energy being consumed on critical electrical components. It is possible that the temperature at this time is the limit temperature (Figure 6 below). ). Due to the need to balance various performance requirements, each configuration may cause different problems, resulting in different possible solutions. This is bound to define the drawings and BOM of each solution in the design process, which brings design and development work. huge challenge. This also requires LED control manufacturers not only to manufacture such products, but also to carry out a large number of test verification work to reduce the trouble in the application process.
The form of LED is generally a single particle, and even if its luminous efficiency is continuously increasing to a level of 100 lm/W or more, the amount of light emitted by a single particle is still limited. When a suitable luminous flux is required according to the lighting requirements, a combination of a plurality of particles is often required to achieve such a light requirement. For example, some high-powered floodlights , street lamps, downlights, and the like require a combination of a plurality of particles. In addition, for linear lamps that are widely used in buildings, it is far from impossible to achieve this effect by relying on one LED.
It is difficult for us to redesign different numbers of LED boards to make products for different applications. This is not economical for lighting companies, whether it is for design, manufacturing, purchasing or warehousing. In the manufacture of such a product with a relatively large number of LEDs, in order to replace the maintenance, to make the production easy and efficient, and to give full play to the scale cost advantage in practical applications, especially to facilitate the combination of LEDs to achieve ever-changing applications, we will LED Make the smallest unit we need, the module.
Through the increase, decrease and change of modules, we can produce products that can be applied to different occasions. This is the trend of designing and manufacturing LED lamps. With the improvement of the standardization of LED circuit boards, the scale and generalization of products will be effectively realized. The required lamps can be assembled by arranging and combining various standard components. This method is beneficial to improve the quality control level of the industry and is suitable for Large-scale industrialization. This requires the LED control device to cooperate with the modularization of the LED, to output the electrical parameters required for various applications, and to achieve the economical and modularization of the LED control device.
For example, a company produces LED linear lamps, which are available in 0.5m, 1m, and 1.5m sizes depending on the length. The number of LEDs for each specification is 11, 22 and 33. When a circuit board with a length of 0.5 m and 11 LED particles is selected for modular production, the corresponding linear lamps of different lengths need only one, two or three modules assembled. This eliminates the need to separately develop 22-particle and 33-particle LED boards, which is time consuming and costly.
The modularization trend of LEDs has led to the trend of modularization of LED control devices. Taking the above products as an example, if I choose an LED control device that can drive 11 0.5m LED circuit boards, I only need to use 2 or 3 identical LED control devices to drive 1m or 1.5m products.
The scale of the LED control device is obviously able to control the volume of the product to ensure the light and thin LED lighting, to ensure that SELV helps the product to be safe, and to help improve the performance of the product. We assume that the LED's driving voltage is 3V. If only 11 particles need to be driven, the driving voltage is 33V. However, if we want to drive 22 or 33 particles, the driving voltage will reach 66V and 99V. The higher the driving voltage, the higher the manufacturing requirements of the LED control device, which inevitably increases the manufacturing cost, volume, performance, safety and other factors.
Of course, if an LED luminaire product may use several LED control devices at the same time, the LED control device requirements not only require multiple choices in performance to adapt to different module combinations, but secondly, reliability and safety cannot be exceeded. Reduced by multiple control devices. Because the size of the LED control unit cannot be changed, implementing various configurations in the same size is also a challenge for LED control manufacturers.
combination
The main function of the control unit is to convert the input power to the voltage or current at which the light source operates normally. The input power of the traditional control device is generally AC mains, and the input of the LED control device can be AC ​​mains or DC power. Thus, the drive of the LED can also be achieved by a combination of various control devices without a suitable single LED control device. However, traditional control devices cannot implement such combined applications (Fig. 7 below).
The main benefits of this are:
1) In some special safety applications, such as eaves, swimming pools, important political buildings, etc., the main part of the lamp is SELV to ensure the safety of the building and to protect the safety of the user.
2) In order to achieve various application requirements, it is only necessary to design the DC conversion part to increase the amount of power supply, which can greatly reduce the cost and avoid the need to select a special adapter controller for each application.
3) It can also adapt to the volume of various LED lamps, so that the products can adapt to various harsh installation applications. In order to achieve a more beautiful design, the LED driver power supply is often removed from the product. And reduce the impact of heat on the LED.
However, the problem that comes with it is that there are too many control devices, the reliability is poor, and the volume is large. Various controls directly require a reliable connection. Once a certain link is wrong, the whole system will have problems.
Indoor and outdoor applications
Due to the energy saving and color characteristics of LEDs, LEDs are first used in outdoor lighting applications such as street lights, linear lights and buried lights. These types of lamps often have strict water and dust resistance requirements. In practical applications, since the control device is a short board of the lighting system, the lamp is often separated from the control device in consideration of the convenience of maintenance and the need for a safe low voltage in some special occasions. This requires the LED control unit to have the same level of protection as the luminaire. This is also the market we will see a lot of LED control devices with IP ratings. In engineering, LED recessed luminaires are often separated from the lamp body, which also has a large demand for stand-alone LED control devices. These are market characteristics that are significantly different from traditional control devices.
A large number of outdoor applications also require LED control devices to adapt to various extreme temperature conditions, which is a great test for the selection of components. Since most of the energy of LED lamps is converted into heat, the heat dissipation capability will directly affect the life of the LEDs, and thus the life of the LED lamp system. In such a relatively high temperature environment, as the temperature increases, the load capacity of the LED control device also decreases, and the professional manufacturer will give the derating curve of the control device. In addition, in outdoor applications, LED control devices should also consider lightning surge requirements (Figure 8 below).
Conclusion
LED control devices are becoming more and more recognized as a key part of LED lamps. In addition to the great difference between the design principle and the traditional control device, people gradually find that the original knowledge of the control device cannot be applied to the LED control device. In practical applications, we should pay close attention to the development trend of the technicalization of LED control devices, and we must have a correct understanding so that we can really use it. Similarly, only by recognizing the trends in the application can we guide our companies and designers to design the LED controls that are really needed for LED luminaire manufacturers.
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