作者：Blade

samsung led lighting products and design method

With the development of white LED lights, it’s more widely applied. In the past, the white LED is the most common application is as a small-size color LCD backlight. White LED brightness increase, its application has spread to other areas, such as a flashlight or cell phone camera auxiliary lighting. This paper describes a general boost chip to drive the efficient high-current LED circuit.
Circuit design

samsung led lighting products and design method

General white LED current is about 20mA, but the high brightness LED 200 to 300mA current. If the product needs to use three to four high-brightness white LED, the brightness average general practice is to string them connected together. On the market, most of the white LED driver chip can only drive 20mA. Hit a series high current LED applications will have to think of other ways. Intersil’s EL7516 is a typical step-up chip, this chip operates at 1.2MHz fixed-frequency PWM mode, built-in 1.5A, 200mΩ MOSFETs. Figure 1 shows the the EL7516 typical application circuit. DC-DC boost the role of EL7516 will be 2.7 ~ 5.5V input into a constant voltage of 12V. General PWM control chip, the FB pin is connected to the error amplifier is compared with 1.3V. R1, R2 resistor value is selected to set the output voltage.

 

The EL7516 Boost Application Circuit

EL7516 voltage circuit into a constant-current LED drive circuit is very simple. Shown in Figure 2, the FB pin of R1 replaced by LED, change R2 can adjust the current through the LED. The value of R2 can be selected from the following formula: R2 = VFB / Iled where VFB is the FB pin voltage, that is, 1.3V; Iled current through the LED.

Standard LED driver circuit

EL7516 used to drive four high-brightness white LED tube

R2 by 300mA, the resistance of the power consumption is close to 0.39W. Such a great power not only affect the efficiency, but also need to use the relatively large size of the resistance in order to accept the 0.39W of heat. In general, these applications are battery-powered, efficiency and line PCB space requirements are more stringent now let us look at how to improve the efficiency of this line.

Regardless of the circuit changes how EL7516 will adjust the duty cycle so that the FB voltage to maintain 1.3V. The assumption D1 positive voltage drop is 0.6V, the voltage drop across R2 is about 0.7V. To maintain a 300mA LED current, R2 can be used to 2.3Ω. R2 power consumption also dropped from the original 0.39W 0.21W. Although the power consumption has been reduced, but R2 have to use a half-watt resistor to this circuit.

A cheap TL431 added to the circuit as a 2.5V reference. As mentioned earlier, the EL7516 will keep the FB in 1.3V; so the current through R4 is: (2.5-1.3) / 20k = 60mA. FB is a high-impedance pins, we assume that this 60mA full inflow of R5, made the same 1.2V voltage drop. 0.1V, the rest of the R2 to complete. In order to facilitate the purchase, R2 is selected as 0.39Ω. So the current through the LED is about: 0.1/0.39 = 255mA. R2, the power consumption is significantly reduced to: 0.1 × 0.255 = 26mW.

Conclusion

Can be seen from the above experiments, minor changes can greatly improve the efficiency of high-current LED panel in the circuit. Experiments, we use a 5V input. The practical application is likely to be a single lithium battery power supply. The EL7516 minimum operating voltage of 2.3V, so apply to a single lithium battery power supply. EL7516 built-in MOSFET peak current (1.3A min) protection, such as the lithium battery voltage dropped below 3V, drive four LEDs may trigger the current protection. Such as the need to 3V below work best to reduce the output for the three LEDs.

sbc led bulb and led design

When the output voltage may be higher than the input voltage may be lower than the discontinuous buck-boost converter peak current mode control LED driver is a good choice. However, this buck-boost converter used to drive design, the LED voltage change will change the LED current to LED open circuit will produce high output voltage, thereby damaging the converter. This article will discuss in detail this applied to the LED lights converter design, and describe a variety of overcoming the inherent shortcomings of the method.

sbc led bulb and led design

The light-emitting diode (LED street lights) applications have been for many years, with the latest technological advances, is becoming a strong competitor in the lighting market. The new high-brightness LED has a long life (100,000 hours) and high efficiency (about 30 lumens / watt). The past three decades, the LED light output brightness every 18 ~ 24 will double, and this growth momentum will continue, this trend is called Haitz law, which is equivalent LED Moore’s Law.

 

Figure 1a: LED connected in parallel. Figure 1b: LED series connection.
Electrically similar to the LED and diode is a one-way conductive (although the reverse blocking capability is not very good, high reverse voltage is very easy to damage the LED), similar to the conventional diode low dynamic impedance VI characteristics. In addition, LEDs are generally safe conduction of the rated current (rated current of the high brightness LED typically is 350mA or 700mA). Rated current, LED forward voltage drop of the difference may be relatively large, typically 350mA white LED voltage drop between 3 to 4V.

The drive LED controlled DC current. In order to make the long life of the LED, the LED current ripple must be very low, and high ripple current causes the LED to produce large resistive power consumption, reduces the LED life. LED driver circuit is the need for higher efficiency, because the overall efficiency depends not only on the LED drive circuit. Work in the current control mode switching converter is ideal drive options to meet LED applications with high power and high efficiency requirements.

Drive multiple LEDs also need careful consideration. For the following two reasons, is not recommended as shown in Figure 1a as parallel LED strings: dynamic impedance and forward voltage drop of each LED is not the same, if there is no external current circuit (current mirror), impossible to guarantee that flow through the LED the same current; an LED failure will make the LED string is disconnected, resulting in LED current is distributed between the rest of the LED string, which will lead to increased current in the LED string, and may damage the LED.

Therefore, a better approach is the LED in series. The disadvantage is that if one LED fails, the entire LED string will stop working. An easy way to let the rest of the LED string to continue working is a Zener diode (rated voltage greater than the maximum LED voltage) shown in each (or group) LED in parallel, as shown in Figure 1b. In this way, any one LED fails, its current will flow to the rest of the Zener diode LED string can still work.

The basic single-stage switching converter can be divided into three categories: the buck converter, boost converter and buck-boost converter. When the LED string voltage is lower than the input voltage, the buck converter (Figure 2a) is the ideal choice; when the input voltage is always lower than the string output voltage, the boost converter is more appropriate (Figure 2b); when The output voltage may be higher than may be lower than the input voltage (caused by changes in output or input), the buck-boost converter (Figure 2c) is more appropriate. The disadvantage of the boost converter, input voltage transients (allows input voltage increases and exceeds the output voltage) will result in the LED upstream a large current (low dynamic impedance load), thereby damaging the LED. Buck-boost converter can replace the boost converter input voltage transient does not affect the LED current.

Buck-boost converter works

LED driver for low voltage applications, the buck-boost converter is a good choice. A variety of reasons, some of which are listed below: They can be used above and below the voltage of the input voltage to drive the LED grow lights strings (boost and buck); high efficiency (it is easy to reach more than 85%); discontinuous suppress the input voltage changes of work mode (to provide good line voltage regulation); peak current control mode allows the converter to regulate the LED current, without the need for complex compensation (simplified design); very easy to implement linear and PWM LED dimming; switch transistor failure will not damage the LED.
Figure 2a: buck converter. Figure 2b: boost converter. Figure 2c: buck-boost converter.

However, this approach there are still two shortcomings: the peak current controlled and discontinuous current mode buck-boost converter is a constant power converter, so any changes will cause the LED current in the LED string voltage corresponding change ; Another problem is that LED open circuit condition in the circuit to produce damage to the high voltage of the converter; In addition, additional circuitry is required to a constant power converter into a constant current converter, and protection in the case of no-load converter.

Figure 3 for the lifting pressure converter application circuit diagram, the controller has built-in used to set the switching frequency of the oscillator. The beginning of the switching cycle, Q1 turns on. Due to the input voltage VIN added to the inductor, the inductor current (iL (t)) from zero (initial steady state) began to rise.

screw in led bulbs and led tree

As people work, study, leisure and entertainment environment, continuous improvement and beautification of the city, lighting engineering are constantly changed. Electronic fireworks trees as landscaping, lighting project is an important landscape, has been the focus. However, the existing electronic fireworks tree is a low-voltage small light bulb as a light source, and highlights the large power consumption, short life, easily damaged, and the lack of color, serious shortcomings in actual use.

LED is an excellent display, long life, energy-saving, high brightness, a variety of luminous colors, fast response and low driving voltage. Low-voltage small light bulbs replaced with LED lights source device simulation fireworks tree, not only can overcome its shortcomings, but also has power-saving, long working life, high brightness, multi-light-emitting color, fast response, etc., and save a lot of energy also can make the work of electronic fireworks more colorful and fascinating.

screw in led bulbs and led tree

Embedded microprocessor with LED display electronic fireworks tree controller is at the core, supported by appropriate drive circuit composed of. The controller can be under the control of the dedicated control software, the corresponding work.

 

A hardware circuit design

In order to ensure a good system to maintain performance and meet the system expansion requirements, LED flood lights electronic fireworks tree controller hardware circuit design, the modular design of the insert plate. The main control circuit board and the drive circuit board is divided into two flapper, each completed independent of the different functions of the two flapper in accordance with the geometric dimensions is equivalent to the size of the PCB design. An LED electronic fireworks tree controller requires only a main control circuit board and a number of pieces of the drive circuit board (depending on the size of the LED electronic fireworks tree). The main control circuit board to control the various driver circuit board through a custom bus. In practical work, the main control circuit board and the drive circuit board inserted in the “cage” rail between each flapper 26-pin flat cable to bus interconnect, and thus can be easily system expansion and system maintenance becomes simple and fast.

1.1 the main control circuit board design

LED electronic fireworks tree is embedded microprocessor 89C52 (IC5) core data bus only export the data of the data bus and address bus in the drive through the 74HC244 bus driver (IC1, IC2) should be into the interconnection bus in order to increase the anti-jamming capability of the system. Programmable gate array chip GAL16V8 (IC3) as the output of high-end chip address decoder can simplify the decoding circuit but also to ensure the uniqueness of each output chip address decoder. Hardware “watchdog” timer circuit using RC oscillator fluctuations in counter, the CMOS chip CD4060 (IC4) mainly consisting of C1, R1 and VD2 composed of a power-on reset circuit. Change the value of R2 or C3 can fine-tune the working hours of the “watchdog” timer, change the VD3 positive pin to the CD4060 output pin connection location can be multiplied to change the working hours of the “watchdog” timer. Jumper switch K1 is mainly used to simulate the display shells to launch the process of rate setting, the jumper switch K2 is given for the analog display shells at high altitude explosion speed. Bus interconnection can be achieved through a dedicated interface (Z1). LED electronic fireworks tree of the main control circuit board circuit diagram shown in Figure 1.

 

1.2 drive control circuit board design

The circuit of the drive circuit board circuit schematic shown in Figure 2. In order to facilitate system expansion, the drive circuit using slot structure design, each output flapper selection the four TPIC6B273 data latches, power driver and output. TPIC6B273 as the combination of 74LS273 and MC1413 (MC1413 only 7 channels output driver TPIC6B273 for 8-channel output driver), which is produced by the U.S. TI Company set eight data latches, power driver for one of the 8-channel D-type trigger device power output device has eight data latches, the composite data-driven output control. Therefore, the application circuit design of the device is very simple.

Figure 2, by comparison decoding chip 74HC688 (IC2) and a 2-4 decoder chip 74HC393 (IC6) and jumper switch K1 matched to complete the decoding of the variable address, and can select the output driver chip (IC1 IC3, IC4 and IC5), strobe, data latches. As a result of the six variable address decoder, LED electronic fireworks tree controller can be expanded to drive 26 = 64 driver board.

LED working status of the electronic fireworks tree is short-term dynamic work status, and selection of ultra-high brightness LED tubes as a light-emitting element, set its short-term transient operating current of 45mA (3 ~ 4 times the rated static operating current), mixed the average tube with colored LED voltage drop of 2.5 volts, the chip each output (load basis TPIC6B273, performance, and current limit) to drive three parallel (3 × 45 = 135mA <150mA), and (according to TPIC6B273 load voltage limit) 20 series LED (2.5 × 20 = 50V). Thus, every one of TPIC6B273 drive output can theoretically drive the LED is:  2.5 × 20  × 3 = 150. In fact, in order to work reliable derating choose to drive half the number of LED (80). Fireworks tree of each electronic driver board has four driver chips, each chip eight, each electronic fireworks tree driver board to drive the LED is: 80 × 8 × 4 = 2560. Can be the basis for the design of electronic fireworks the size of the tree (using the number of LED’s) to select a different number of drive circuit board.

2 control software design

LED electronic fireworks tree by the trunk (for analog display shells fired off process) and branches (for simulation display shells at high altitude explosion landscape) and two display parts. Electronic fireworks tree work at night, as the branches of the support body, the trunk has been extremely vague on the branches and trunks of different LED display light of the source of the controlled work will simulate the entire work process display shells from launch to explosion .

The main task of the electronic fireworks tree software design is the process of the work of the analog display shells (fired – explosion), especially in high-altitude explosion landscape. The design  first high-altitude landscape named (such as the dream world, earth red, sky full of stars, etc.)  drawing and designing their specific work processes and phenomena according to their landscape, and so to prepare the appropriate display software modules. An electronic fireworks tree 10 to 16 display modules can be designed to increase the display pattern. Enable the viewer to work long hours in order to protect the electronic fireworks tree boring, each work cycle randomly generate a display module order coexist in a linear table, the control procedures in order to check the data in the linear worksheet Decide which one module. Vary due to display the working status of the working module, Figure 3 gives only the main workflow of the electronic fireworks tree.

3 Conclusion

The LED electronic fireworks tree and its controller after prolonged use in the winter, summer and harsh environmental conditions proved that the system is reliable, prominent, obvious advantages.

shop led lighting and new white led

With the color LCD increasingly wide range of applications in handheld devices, the demand for compact and inexpensive white backlight, and more and more widely. Traditional program uses a cold cathode fluorescent lamp (CCFL) and electroluminescent (EL) panels, but these circuits for the current hand-held consumer products to large size, expensive, complex and other institutions of higher. At present, the recent development of LED technology has produced a white light LED. White LED lights and mass
Ship compared to the backlight has many advantages, including small size, low cost, low complexity and high reliability.

Today, a new generation of multi-functional cellular phone has been widely used in the domestic market. A new generation of mobile phones is not only compact size, and integration of more functions, such as PDA functions, to close / e-mail, text messaging services, as well as browse the Internet letter in a large size, rich colors on the monitor. Some mobile phone models
Also includes a frequency modulation (FM) radio. MP3 players, and even higher resolution digital cameras.

Whatever its function, the consumers, and always look forward to providing long-lasting battery life in handheld devices without increasing the size of the case. That is, not only in a small receiver with more features at the same time consume less power. Such a power management design is extremely demanding requirements. In response to the Peach war, manufacturers must address the following topics:

Power Manager IC (PMIC) on the basis of further deepen and broaden the application of trendy white LED technology and devices, to complete a new handheld or mobile phone supporting the best choice. This article presents a white LED trendy technology and devices to be introduced.

2, the white LED lamp is a new technology program

shop led lighting and new white led

2.1 compact non-inductive boost circuit MAX1759-regulation white bias current

Typical of the white LED forward voltage of about 3.5V ± 10%, only for the device to provide a positive bias to white light. Need to step-up circuit when the white light LED forward voltage than the battery voltage, the traditional solution is to use the boost circuit, through the ballast resistor provides bias for the LED, this program there are two defects: First, the white LED more the wide range of forward voltage variations can cause large changes in bias current, the brightness deviation; Secondly, the traditional step-up program have a DC path between input and output (even in the off state), so that does not work LED unnecessary consumption of battery current.

To overcome the above drawbacks, a new non-inductive boost circuit MAXl759 (regulator type buck / boost charge pump) is a compact solution, shown in Figure 1 circuit. The regulator type l / step-down charge pump (uMAX) package of small size, can provide 100mA output current. In accordance with the configuration in Figure 1, can be directly provide a stable bias current of white LED bias multiple parallel LED with good brightness distribution. MAXl759 circuit shutdown there is no DC path between input and output, users can take advantage of the input control backlight pass, breaking. The circuit also with a power-good (POK) output, whether it has been prepared to inform the microprocessor backlight good.

The huge export opportunities of all lighting, participating in the global competition to be innovative

A number of large technology enterprises successfully participated in the “siege” outside to the global LED lights industry chain, and increasingly occupy an important position. International predators have approaching from various quarters of this vast market of mainland China, the economic power of more growth in the Chinese folk from the land of China toward the United States and Europa, looking ahead, from the streets of Florida to skimming over the surface of the metropolis of France, all lighting from the glory of the Russian theater dancing to Tokyo Osaka. Light the spark of “Made in China” on the world map.

all lighting

Faced with the business opportunities also needs to innovate

At present, although the process of world economic recovery is slow, there are still many uncertainties. But overall, exports are still an important part of China LED companies to participate in global competition and market share, and there are tremendous business opportunities.

LED lamps huge export opportunities to participate in the global competition to be innovative Faced with business opportunities, how to quickly create new advantages to participate in global economic cooperation and competition? In the next five to ten years, China’s cost advantage will come to and end… New advantages for China’s participation in global economic cooperation and competition, changes in the mode of competition, we should shift from OEM mode to autonomous mode of technological innovation, market innovation, market innovation, management and organizational innovation model up, to achieve the technical content, value-added ability to shift from low-to high -end.

China LED products are exported mainly in the packaging and application aspects

In recent years, many LED companies, thousands of miles away overseas markets, but more like a fly freely vast. The Pearl River Delta and Yangtze River Delta region of LED manufacturing companies, many companies exports accounted for more than 50% to 70% proportion. Analysis of the industry, rapid export growth of the main reasons. First, the development of the domestic market is relatively speaking, and not mature; Second, A global scale, many countries are stepping up legislation to encourage the use of energy-saving light.  Meanwhile, the LED industry development is not only for all lighting and semiconductor industry which has a strategic leading role, but also lead to a series of end-consumer appliances, automobiles, mobile phones and other technological change, governments around the world to increase support to the LED industry policy.

 

shop led lights and led drivers

We developed an array of signal processing systems (led lights), due to the array antenna must be placed in the surrounding open area, and array signal processing unit is located in a circular array antenna central location, which requires a computer outside of the array signal processing unit in 1 ~ 2km between the duplex communication. Proportion in the time index in the entire system in order to reduce the data transmission time, the data transfer rate should be not less than the rate of E1 (2.048Mb / s), and ask the communications link is safe, reliable. Analysis of various data communication technologies, the final choice of a fiber-optic key road, and achieved satisfactory results.

A copper media data link

Also requires a higher data transmission rates and longer communication distance in the copper media link coding and modulation is difficult to meet the index requirements, but the high-speed modem is not only expensive, but the handshake process time-consuming random real-time requirements field of the transmission data will obviously not apply. The most important thing is that the traditional copper media link produces both electromagnetic interference signals, and also easily affected by electromagnetic interference, and difficult to meet the requirements of the EMC (electromagnetic compatibility) and EMI (electromagnetic interference) standards.

Analysis of two fiber-optic link

The traditional image of the people, the fiber used in short-distance communication is not economical, but it has a copper media key road incomparable advantages: ① fiber link is neither emit electromagnetic wave, is not affected, there is no interference between the fiber error rate is greatly reduced. The designers do not consider the incoming ambient noise may be coupled; ② fiber to provide a communication link between the two electrically isolated to eliminate the problems caused by ground potential between the long-distance equipment. Designers no longer have to impedance matching and a headache; ③ fiber-optic transmitter can be digital modulation driving circuit. Digital baseband signal through a simple line coding, you can directly drive the fiber optic transmitter.

Now, the price of fiber optic devices than ever before has been a sharp decline, With the cable price increases and the fiber-optic device prices to decline further in the future, when people choose fiber is no longer first consider the price factor. Therefore, considering the speed and distance indicators, select the appropriate type of fiber transceiver and its drive circuit, high performance and low cost fiber-optic communication key road, this is the focus of this paper to.

The choice of optical fiber communication devices

A basic fiber-optic communication system is very simple: an LED panel emitter electrical signals into optical signals, and the coupling into the transmission fiber, the optical signal through the fiber to reach the optical receiver, the received optical signal back into the original the electrical signal output.
· Cable options: general, quartz glass fiber due to its low loss, high bandwidth for long-distance communications links, such as Ethernet and FDDI standard specifies multimode 62.5/125μm quartz glass fiber. Thin core fiber requires high-precision connectors to reduce the coupling loss, low-cost cables and connectors for industrial applications. 1mm POF (Plymer Optical Fibers) and 200μm HCS (Hard Clad Silica) fiber is the best choice, they are the step-index multimode fiber.
1mm POF typical loss value at 650nm wavelength is 0.2dB / m, 200μm HCS fiber to only 8dB/km 650mm wavelength typical loss value, less in the 820nm wavelength. HCS fiber is the core of the quartz glass cladding is a patented high-strength polymers, not only increased the intensity of the optical fiber, and moisture, pollution prevention and the outer sheath of PVC 2.2mm. HCS fiber can work in a 40 ℃ ~ +85 ℃ temperature range, the erection of a temperature range of 20 ℃ to +85 ° C, in both performance and price to meet the system requirements.
· Operating wavelength choice: fiber optic communication system design must take into account the impact of fiber loss and dispersion of the system, due to loss and dispersion are related to the operating wavelength of the system, the operating wavelength choose to become a major problem in system design. Consider the system specifications and selected fiber, select the 820nm wavelength enables HCS fiber loss as low as 6dB/km dispersion has reached the minimum.
· Choice of light source: LED can be selected in the 820m wavelength light compared with the semiconductor laser, the LED drive circuit is simple and low cost.

shop led lights and led drivers
In summary, the cable selection 200μm HCS fiber optical transceiver device selection of the 820nm wavelength of the HP’s HFBR-0400 series. In the 1500m distance in the series HFBR-14X2/HFBR- 24X2 reach 5MBd rate of the operating temperature range from 40 ℃ to +85 ° C, ST, SMA, SC and FC, multiple port models to choose from. HFBR-14XZ type AlGaAs LED tubes with 820nm wavelength HFBR-24XZ internal integration of an IC chip including PIN photo detector, the DC amplifier, and the open collector output Schottky transistor, its output directly with popular TTL and CMOS IC connected.

4 A practical fiber optic LED driver circuit

The fiber optic duplex communication system in which the role of the driver circuit is to convert electrical power into optical power, and modulation of the transmission of electrical signals to the output of the light source, its light while providing the bias current and changes with the digital signal modulation current.

Design LED driver circuit must first consider the peak of the LED drive current, and if more than the peak drive current produced by the optical signal will overshoot phenomenon. Chong, resulting in the receiving device to cause the signal coupled from the amplifier noise, the results may be beyond the detection threshold of the comparator, causing the error. LED has extinguished than the features lit difficulties, it will produce a smearing, This phenomenon is particularly evident when using the serial driver circuit. The parallel drive mode can provide a low resistance channel for the carrier in the LED, thereby reducing the pulse width distortion and slow smearing.

Resistance RSI in the drive circuit is used to adjust the optical output power, be careful not to exceed the peak drive current of the LED, or optical signal will overshoot. Another circuit of the SN75451 with the characteristics of low impedance, high current rate, to avoid the long tail phenomenon.

Pulse width distortion (PWD) is a major factor to limit the rate of fiber-optic link, which is caused by transmission delay between the input and output are not equal. Noted that PWD is always positive, so we can take advantage of the RC circuit to delay the LED is lit.

The optical receiver circuit is an important part of the optical fiber communication system, its performance is good or bad is a comprehensive reflection of the optical fiber communication system performance. Its role is to optical fiber transmission over optical signals into electrical signals, then amplified and balanced, the decision circuit and restore the original signal of the transmitter.

The presence or absence of the commonly used optical signal in optical fiber transmission line, “1” and “0” code in order to avoid the long stream even “0” or long even “one”, conducive to the extraction of the clock, the need for coding circuit. Array signal processor is sent to the parallel data rate and conversion circuits.

Comparisons between conventional tunnel lighting technology and LED tunnel lighting technology

Currently, tunnel lighting still utilized high pressure sodium lamps as lighting sources. But in recent researches, scientists found that high pressure sodium lamps has a relatively high radiation value, which was far exceeds the safety indicator and caused potential damages to human bodies. Besides high pressure sodium lamps have defects in CRI, the visual sensitivity characteristic, power specifications and brightness control. The new developed LED tunnel lighting technology overcame all sorts of disadvantages brought by high pressure sodium tunnel lamps and became the mainstream in tunnel lighting area.

 

Comparisons between conventional tunnel lighting technology and LED tunnel lighting technology

 

Light Emitting Diode is a new lighting technology based on semiconductor technique. In the early stage, LED can only emit red rays, which were mainly used as indicators in electrical appliances. With the development of LED technology, LED can send out multiple color rays. Nowadays, LED technology has been commonly used in many industries, such like display, single lighting, backlighting, street lighting, tunnel lighting, vehicle lighting, outdoor landscape lighting and indoor lighting. The biggest advantage of LED tunnel lighting technology is light dimmable. Many LED manufactures started to think over embedding calculation components within their LED tunneling lighting products to make them more intelligent and more human-based.

 

Properties of LED tunnel lighting technology:

1)       Consume less power. Compared with traditional high pressure sodium lamps, LED tunnel lights can save more than 40% energy.

2)       High longer service life. In ideal conditions, LED tunnel lights can continuously work for 100,000 hours.

3)       Higher reliability. Costs of daily maintenance and repair are quite low. The average normal working (without any faults) time can reach up to 20,000 hours, while high pressure sodium lights can maintain a constant normal working for less than 10,000 hours.

4)       Reduce the costs of power distribution system (cables, transformers, distribution boxes, bridges, etc.). In cases of long distance projects, the costs of power distribution system occupied a large ratio. Applying LED lighting technology can dramatically reduce the costs.

5)       LED tunnel lights can realize “instant-on”, easy for brightness adjustment, with no flickers, with wide start voltage range, embedded with multiple energy-saving modes (like intelligently adjust brightness according to the number of cars within tunnels).

6)       LED tunnels lights are free of toxic chemical pollution substances, such like mercury, lead and other health-hazard materials.

LED area light source technology found breakthrough in Nanjing

LED lighting technology is more advanced than traditional lighting in energy consuming, environmental protection and health-hazard aspects. The current used lighting source for LED lights is so called “spot lighting source”, which has some defects: inevitable lighting attenuation, higher costs and poor performance of cooling sections. These defects exerted a bad effect on their promotion process. With the becoming mature of LED chip technology, “area light sources” are no longer a myth. Then designers and LED engineers started to realize that replacing spot light sources by LED area light source technology is a key point to overcoming the defects of the existing LED lighting products. Under the support of the “Nanjing 321 plan” issued by Nanjing Government in last month, LED area light source technology found breakthrough in Nanjing.

 

LED area light source technology found breakthrough in Nanjing

 

In the Science and Innovation Park of Nanjing University of Technology reporters found this “area light source”. Nanjing XiongYan Optoelectronics Technology Co., Ltd. demonstrated a recently developed table lamps used LED area light source technology. Only judging from the space, this table lamp has nothing special, just like an ordinary table light. However, it is amazed that this LED table light has no bulbs but still can emit soft yellow white rays.

 

“All light are coming from this small light-emitting sheet.” Introduced by Mr. Guohua Bian, general manager of Nanjing XiongYan Optoelectronics Technology Co., Ltd.. On his palm we found a tiny circular sheet (with a diameter around 4cm, with a wideness about 1mm, and covered with yellow phosphor powder and small black spots), which is rather unnoticeable. “Each black spot is a lighting source. All these 3000 thousand small lighting sources have been evenly arranged on this sheet. We called it are light source. Every sheet consumes a power of 3W, but can replace a 20W traditional table lights. This table light has been installed 10 pieces lighting sheets just like this one, which means this lamps are equivalent to a 100W filament table lights. ”

 

In Mr. Bian’s words, his company spent totally 30 million yuan on developing LED area light source technology. It is a light source technology that more advanced than spot light source, less light attenuation, more easily-be-realized cooling design.

Analysis for LED explosion proof lighting technology

LED explosion proof lighting technology is typically led lights used in places which have relatively high risks in explosion, such like chemical plants, mines and gas stations. These places are full filled with explosive mixtures: explosive gas atmospheres, explosive dust environment and methane gas. Specific measurements should be taken before installing corresponding explosion-proof lamps. One of the most important working principles of LED explosive lights is restrict the contact surface of covers/shells with explosive gases or dusts and meanwhile keep the surface temperature of lamp compartments and electronic components under a safe level. Normally, this safe level is set as the minimum ignition temperature of the surrounding explosive gases. That the reason why measurements and tests should be conducted before installing these lamps. Only in the condition of knowing the major constitutions of the gas mixtures that suitable LED explosion proof lamps can be chosen.

 

LED explosion proof lighting technology is typically used in places which have relatively high risks in explosion, such like chemical plants, mines and gas stations.

 

LED is classified as a type cold solid lighting source, with high eletro-optical conversion efficiency, lower level of heat generation and longer service life. Thus high-power White-ray LED Explosion Proof Lamps are ideal lighting applications. Once promoted, LED explosion proof lighting technology gain a rapid development in this area.

 

LED explosion proof lights are mainly composed of lamp shells, lamp covers mounted in front of metal shells, internal lighting sources and batteries, switches and other compartments. Their major properties:

 

Lighting sources are made up of high-power LED modules. Wide input voltage drives (include constant-current chips, power supplier module) are set between lighting sources and batteries. In most cases, power supplier modules are connected directly with constant-current chips and plastically sealed together with LED modules.

 

The low heat generation of LED lighting sources helped to realize the internal temperature control property to some degrees. Both in battery-fully-charged phases and in battery-nearly-worn-out phases, LED lighting sources can maintain a constant brightness. Low-power LED explosion-proof lights are usually made as portable. It is a recently-developed technology according to the demand of the market. Heat sinks are set on the surface of shells (within lamp covers), which can effectively conduction unwanted heat created during the operation. LED explosive-proof lamps are more reliable than other LED lighting products and were used in a variety of industries, such as coal, petroleum, railway, etc.

Intelligent LED Street Lighting System has bright future

With the continuous progress of society, more and more household items and electrical appliances are developing towards an intelligent direction, using the much humanized operation design. It is no doubt that smart phones are the most outstanding one, yielding too much surprises and happiness. As a part of emerging industry, LED lighting also applied a variety of intelligent designs, especially in LED street lamps, LED Tunnel Lights and high-power LED power suppliers.

 

With the continuous progress of society, more and more household items and electrical appliances are developing towards an intelligent direction, using the much humanized operation design.

 

Intelligent LED Street Lighting System utilized centralized monitoring and control, dimming LED street lamps conditionally according to specific using requirements. It is proved that the average energy-saving level of the entire system is around 20% to 30%, and the average service life of lamps can be extended by around 10%. Preset information will be embedded into CU in advanced. Once failed in some branches, the central controller can detect breakdowns immediately and give prompt responds.

 

Intelligent LED Street Lighting System used on bridges used TCI/IP protocol. After optimized signal transmission, more lamps can be connected into LED lighting system and consequently extend applying distance. The transmission control protocol can increase the reliability of Intelligent LED Street Lighting System. In next sections, we will list several main functions of this system:

 

1)       100 levels for brightness adjustments and 16 levels for gray-scale loss of brightness adjustment.

2)       Frequency can reach up to 85Hz.

3)       256 RGB color adjustment capacities.

4)       Brightness depth can reach up to 1024.

5)       Every individual controller can automatically sample input signal.

6)       Support user-configure.

7)       Power supplier: 24VDC/110-220VAC.

8)       Support remote control and serial communication.

 

Synchronous operations can be realized by this system, no asynchronism, approximately zero power supply errors. The average luminous flux should be maintained on a level of 100lx. The stimulating system is not base on surrounding brightness rather than time. External optical sensors detect surrounding light intensity at a frequency of 10/mins. Once the value fall below a certain value (brightness threshold), the central controller will send out a “switch on” signal to each individual triggers. It is cleared that this intelligent lighting system can automatically adjust “switching time”, also can be successfully turned on in rainy and fog days. LED lights manufacturers began to add solar energy technology into this system, making it more environmental friendly.