Design of the hottest LED lighting products

  • Detail

LED lighting replacement product design

development trend of LED lighting

light emitting diode (LED) is a rapidly developing technology, which is widely used in many general lighting fields, usually called solid-state lighting. Typical applications of LED lighting are: indoor lighting (for commercial, industrial and residential environments), outdoor lighting (street lamps, parking lot "lighting), architectural and decorative lighting, etc. at first, led was used for decorative lighting because it can emit the color of the entire spectrum

in some cases, LED has become an effective solution for building lighting. Compared with other lighting technologies, LED has better performance, so it has become the mainstream solution in the current general lighting market:

compared with other lighting technologies, LED has a longer service life. The working life of LED is up to 50000 hours, while the service life of incandescent lamp is only 1000 to 2000 hours, and the service life of small fluorescent lamp (CFL) is about 5000 to 10000 hours. The significant advantage in service life makes led very suitable for commercial and industrial applications that need to invest a large labor cost to replace lighting lamps

energy efficiency is better than incandescent lamps and halogen lamps, and is equivalent to fluorescent lamps. In addition, the efficiency of LED is also improving; The efficiency of white LED (WLED) is expected to increase by about 50% in the next 3 to 4 years

smaller overall dimensions. The overall dimensions of LED lamps are equivalent to MR16 and GU10, but CFL cannot meet such applications

a suitable driver can be used to provide brightness adjustment. For applications that need to adjust brightness, fluorescent lamps have technical limitations. Although the traditional LED design also encountered similar problems, the innovative LED drive scheme provided by maxim is compatible with SCR dimming and trailing edge dimming design

has strong luminous directivity. Different from other lighting technologies, LED is very suitable for applications requiring directional lighting, such as small angle reflector

it has higher efficiency at lower temperature. The working efficiency of fluorescent lamps will decrease at low temperature. In contrast, LED is very suitable for low temperature working environment, such as refrigerator lamp

the glow color can be easily changed. This advantage makes RGB LED an ideal choice for architectural and situational lighting, which can change the light color in real time according to specific requirements

in a word, LED has many advantages that incandescent lamps and fluorescent lamps do not have. Based on these advantages, designers are also constantly inquiring about the functions needed to explore more applications suitable for LED lighting. However, due to the limited space, we will not repeat it here. This article will mainly discuss LED lighting replacement products, which are used to replace incandescent lamps, halogen lamps or fluorescent lamps of the same specification. These LED lights must be able to be installed in existing specifications and sizes and compatible with existing infrastructure

led replacement lamp

many people believe that led replacement lamp is the fastest growing market of LED lighting at present. The reason for the rapid growth is simple: these lights do not need to update the electrical infrastructure (i.e. wiring, transformers, dimmers and sockets), which is a significant advantage of LED technology

for designers, there are two main challenges in installing LED lights on the existing infrastructure:

1 Overall dimensions. The replacement lamp must be able to be installed into the frame of the previous lamp source

2. Electrically compatible. The replacement lamp must be able to work normally on the existing electrical structure without flashing

next, we will discuss each challenge one by one

install to the existing frame

the existing frame puts forward physical restrictions (that is, the drive plate must be small enough) and thermal restrictions on the replacement lamp. These factors restrict the conditions for designers to change lighting schemes (such as par, R and a specifications). The smaller the size, the greater the difficulties faced by applications, such as MR16 and GU10. For this reason, Maxim introduced a driver IC (max16840) with integrated MOSFET for MR16 applications

size is the key factor restricting the replacement scheme, and thermal limitation is often more critical. LEDs only emit visible light. Unlike other technologies, they do not produce infrared radiation energy. Therefore, white LEDs are more energy efficient than incandescent or halogen lamps, and most of the heat is dissipated through the conductors in the lamp

heat dissipation is the key factor that restricts the light intensity produced by the lamp tube. At present, the LED technology used in lighting replacement products is difficult to reach the brightness level acceptable to the mainstream market. In order to break through the brightness limit, we need to solve the problem of heat dissipation, which is also an essential condition for the successful commercialization of products

heat dissipation also directly affects the service life of the drive board. In order to produce higher light intensity, the lamp must operate at a fairly high temperature (+80 ° C to +100 ° C). At this temperature, the service life of the driving plate will limit the work of the whole lamp, especially the electrolytic capacitor, which has become a thorny problem in the design. Because the electrolytic capacitor will dry quickly under high temperature, under such conditions, the working life of this capacitor will not exceed thousands of hours, which has also become a factor restricting the service life of the whole lamp. Long working life is a major selling point of LED lamps. For designers, electrolytic capacitors with relatively short service life have become the main barrier of design

maxim has launched a unique LED drive scheme for 120vac/230vac input and 12VAC input replacement lamps. These led driving schemes can eliminate the electrolytic capacitor on the circuit board and extend the service life of LED lamps from less than 10000 hours to 90000 hours. Because the electrolytic capacitor is omitted, it also helps to reduce the size of the scheme, so that the drive board can be installed into the small-size replacement lamp frame

compatible with the electrical infrastructure

led replacement lights must work normally under the existing infrastructure, including corner cutting (three terminal bidirectional thyristor and back extension) dimmers and electronic transformers

when 120vac/230vac power supply is connected, the lighting lamp can be adjusted first through the three terminal bidirectional thyristor dimmer. The design of three terminal bidirectional thyristor dimmer can work well, especially the addition of filler must work properly with incandescent lamps and halogen lamps, which are pure resistive loads. However, when using led to transform the lamp, the LED driver is usually a nonlinear, non pure resistance load, and the input bridge rectifier usually absorbs large current transiently when the AC input voltage is at the positive and negative peak. The three terminal bidirectional thyristor dimmer cannot meet this demand of LED, because it can neither provide the required starting current nor maintain current. Thus, the dimmer cannot be started or closed normally during operation, and the LED will flash, which is also an unacceptable phenomenon for the system

as a replacement product, its electrical architecture is more in line with the design of 12VAC input lamps, because electronic transformers and rear edge dimmers can be connected to the input of lamps. If high molecular conductive functional materials can be prepared by combining the good conductivity of graphene, however, the driver of 12VAC input lamp adopts the traditional bridge rectifier and DC-DC converter topology. Due to the incompatibility between transformer and dimmer, flicker will also occur

mr16 (above) and offline (below) lighting scheme block diagram

maxim 120vac/230vac and 12VAC input lighting solution adopts single-stage conversion. By shaping the input current, the lamp will not flicker in the dimming state. These schemes are compatible with the design of bidirectional three terminal thyristor, trailing edge dimmer and electronic transformer. At present, no MR16 scheme has this feature, and few par, R and a lamp schemes have this feature. In addition, our solution also has a power factor correction better than 0.9, requiring very few external components. There is no need for electrolytic capacitors, which will seriously restrict the work of the driving circuit in high temperature environment. Both 120vac/230vac and 12VAC solutions use max16834 IC, which can be evaluated by users and put into mass production. These are the unique solutions of Maxim, and maxim is also the only supplier that can provide this combination of advantages. (end)

Copyright © 2011 JIN SHI