Under the global energy-saving and carbon-reduction boom, LED lighting applications based on semiconductor technology are the most popular energy-saving solutions in daily lighting applications. Because LED lighting has small size and high brightness, it can make creative lighting fixtures according to the setting conditions. Modeling, but as the LED module's brightness and drive power increase, it is also necessary to enhance the protection design of the drive circuit.
According to Forbes, the LED lighting application market will continue to grow in the next five years. By 2020, the global market share of the LED market is expected to reach more than 70%. Because of the rising environmental protection concept, key cities around the world have successively introduced LEDs to replace traditional public lighting applications. In London, for example, it is announced that by 2016, the street modern lighting improvement plan will be completed. The plan will introduce 350,000 urban street lights into LED lighting.
The luminous brightness and driving power of the single component of the LED lighting component are greatly improved. Although the lighting effect is improved, the complexity of the driving power supply design is also increased. The LED driving power module for general indoor use has a built-in basic power protection design to improve the safety of lighting applications.
LED lighting applications are becoming more and more popular.
LED lighting applications are becoming more and more popular. With the upgrade of LED lighting application products, the brightness and power of LEDs are getting higher and higher, and the high current required to drive high-brightness LEDs is required in addition to the heat dissipation requirements of LED chips . Drive circuit design, because the lighting products use lighting for more than 8 hours, the safety of the drive circuit is more important.
In indoor lighting applications, the most common standard LED recessed lights for decorative applications, the driving power varies from 8W to 15W, although indoor lighting is still a small power drive, except for the conventional safety design of the power circuit, because of this kind of decoration The lamps are often installed in closed wooden furniture. In addition to the overload and short-circuit protection design of the power supply circuit, it is also necessary to protect against the power failure of the lamps in the high temperature state, so as to avoid the failure of the lamps and the high heat, the power supply circuit is still in an endless stream. Conveying drive power causes problems to increase.
COB component package improves LED illumination shape and simplifies drive design
Some large-sized xenon lamp products can drive up to 20W or more. Generally, such high-intensity downlights are usually used as the main lighting fixtures for large spaces. The characteristics of such lamps are that they require a single lamp. The brightness performance is matched by a certain number of main lights with sufficient ambient lighting applications. Such well-defined luminaires typically do not use too complex designs and typically use high-brightness LED components in the COB (Chip On Board) package for high-brightness illumination, simplified circuit design, and optimized cost architecture.
However, a single group of light-emitting components is driven by a power supply of up to 20 W. LED lighting for miniaturization and cost optimization is the primary design policy. The actual installation cannot be directly connected to the driver with a low-output power supply module to avoid The drive circuit generates an overload fault. Another important point is that this type of indoor main lighting application, LED power drive will generally require a single luminaire with a set of power drive circuit, the use of drive circuit dispersion configuration can not only make the power drive circuit more streamlined, nor because of the connection of too many luminaires Drive circuit overload problem.
Power safe design protects LED components from drive problems
In the general LED driver power supply design, common protection components include fuses, varistors, and varistor combined with lightning protection devices and Transient Voltage Suppressors (TVS). In the drive circuit through the protection design, the LED light-emitting component is a semiconductor material, which is sensitive to voltage/current transient response. If the power supply changes greatly, the light-emitting component will be broken or burned by high current. The protection circuit technology can quickly power off or bypass when the power supply transient changes, to avoid damage to the LED lighting components.
Compared with indoor LED lighting fixtures, the design requirements for drive circuits related to LED lighting applications for outdoor use are significantly higher. Because outdoor LED lighting fixtures may be used for building exterior wall lighting, landscaping design lighting, or street lighting/indicator lighting applications, it is commonly used to drive directly to the mains grid. Based on outdoor lighting requirements, because the lighting fixtures are set to a higher height, the lighting blocks may be placed in a wide street or park, and the brightness requirements of the lamps will be higher.
Outdoor LED lighting requires high environmental impact
Outdoor lighting fixtures (lighting environments such as tunnels, highways, traffic lights, parking lots, and garages) not only have the brightness of the unit lamps more than several times that of indoor applications, but also the power of the driving power source is several times that of indoor lighting. The safety design requirements are higher, and even the setting conditions of the outdoor public area lighting fixtures are mostly in the outdoor environment. The lamps and driving circuits must also be affected by the environment such as wind, sun and rain, and the long-term high-temperature/low-temperature conversion will also be Test the electronic components of the drive circuit, the durability of the hardware, high power and harsh environment, all of which must be overcome by the safety design of outdoor lighting.
In addition to the more functional outdoor lighting applications, another outdoor lighting application area, which is designed with LED lighting for decorative and situational atmospheres, such as fountain lighting for decorative applications, pool lighting, gardens and sculptures. The landscape auxiliary light source, the rigorous degree of use of these lamps is no less than the general outdoor lighting application LED lamps, the landscaping lamps for swimming pools, fountains, LED lamps must be matched with waterproof stainless steel barrel lamp body, LED lighting components, The driving circuit is wrapped in the stainless steel barrel lamp holder. The heat dissipation in the lamp is mainly transmitted through the lamp body. The safety design of the line is in addition to the requirements of general outdoor lamps. In addition, the problem of possible pool water intrusion lamps must be strengthened to enhance the short circuit safety of the drive circuit. design.
LED luminaires can be quickly popularized, mainly for the LED components of lighting to be continuously optimized in function, so that the lighting application functions are closer to the user's needs. Among them, the LED components use COB (Chip On Board) packaging technology, which can be said that LED lighting applications are more The key to practicality. The COB package is a single or multiple LED light-emitting die, which is directly packaged on a printed circuit board (PCB) by a packaging technology. The COB package type is generally processed by a surface mounted device (SMD) design component. The design of the bracket on the luminaire substrate is very different, because the COB package can directly direct the heat generated by the LED illuminating, the through-contact to the lower substrate, and the heat dissipation treatment through the substrate, and the planarization, a large number of LEDs The components can also form a surface light source illumination similar to conventional luminaires.
A new generation of LED lighting fixtures can use COB technology to bring new-generation LED luminaires closer to those of traditional incandescent, halogen or gas-discharge luminaires. At the same time, LED lighting fixtures need only be driven lower. The electric drive can produce the illumination effect of these traditional lamps. The COB-designed LED module not only enhances heat dissipation (savings the need for more active thermal design of the lamp), but also simplifies the drive circuit through multi-component packaging. Design complexity (because only a single component needs to be driven).
Outdoor lighting applications should enhance lightning/anti-surge protection design
As mentioned above, LED lighting for indoor use is basically sufficient for basic overvoltage, overload, short circuit and high temperature power off/off load design under the utility environment where the use environment is relatively simple and the supply voltage/current is relatively stable. On the contrary, LED street lights , landscaping lights, garden lights, etc., which are installed outdoors, are still insufficient in the above-mentioned basic driving power supply safety protection. The biggest power challenge for outdoor luminaires is still the instability of the power supply and the weather problems of rainy days. The instability of the supply voltage makes the drive circuit susceptible to component aging. This part of the problem can improve the life of the drive power with advanced components that are tolerant to high environments. And the lightning problem must be targeted to improve the solution.
For areas that are prone to lightning and rainy days, outdoor lighting should be enhanced with lightning protection (SPD) design. The so-called lightning protection is used when the lightning strikes unfortunately hits streetlights or landscaping fixtures. The high lamp holder usually forms the best lightning path for the lightning strike.) The SPD protection design can provide a corresponding protection when the instantaneous high-volume surge is introduced into the lamp housing or into the power supply line, and the SPD component can be In addition to the protective effect of lightning strikes, the electrostatic discharge (ESD) can also achieve protection.
The installation cost of the luminaire is expensive. If the lightning protection surge protection design is less costly, it is quite unwise. When the lighting installation is faulty due to the lightning surge, the streetlight can not be used. If the derivative event is large, the streetlight will burn out. Affecting the safety of surrounding people and vehicles, the harm is not as simple as equipment damage. In addition, the increase of street lamp damage rate will also increase the maintenance cost after the installation is completed. In order to avoid electrical hazards such as lightning strikes and power circuit surges, outdoor LED lighting should strengthen the drive circuit safety based on higher than relevant regulations and safety standards. design.
Nantong Boxin Electronic Technology Co., Ltd. , https://www.bosencontrols.com