LED street lamp with intelligent dimming function is imperative

Indubitability, LED lighting is the future trend, reason to support such observations including LED lighting, long life, energy saving and reliability. In addition, the development of LED lighting dimming function, which is also one of the key can replace traditional lighting further. That is not only the LED lamp light or dark two kinds of choices, it must be like the traditional incandescent lamp can provide a dimming function, the LED lamp also has traditional lighting and LED lighting advantages, so inevitably can promote LED lighting is more popular.

For example, in the street lighting part, with the development of technology, when the service life and stability to a certain level, whether the street light will become another emphasis. Basically, although LED lamp standard has not yet complete, but also because of the local product specifications are different, but there are more and more LED street vendors will be intelligent control into one of the LED street lamp function, and power management and daily maintenance points of view, LED street lamp intelligent is imperative, its function is based on whether the environment need someone by car or judge to do the dimming control, in order to increase the service life of the LED street lamp, energy saving effect.

The necessity for LED lamp dimming function, the second generation of Everlight electronics said the company launched the dolphin LED Street (EverlightDolphinII), the lamp efficiency is as high as 100lm/W, and is equipped with adjustable light control function, according to the present environmental brightness adjust LED brightness, this design can be unnecessary waste of power. The new special power supply LED lamp again jinruitong technology recently published, mainly is currently on the market with current as the dimming control cannot make constant voltage problems are improved, the power supply can adjust light under certain voltage, the control signal to provide linear change, so that the output current can be set the corresponding control signal and the linear change of adjustment, to adjust the current intensity does not produce electromagnetic interference effect. It is understood that the LED street lamp system is developed based on the power supply, can save nearly 75% of electricity.

In addition, an upgraded version of the LED street lamp of Shenzhen spark Optoelectronics Technology also uses a new type of intelligent driving power supply, the introduction of a central control system to realize remote monitoring of lamps, lamp brightness can be adjusted in real time (0-100%). The company said, by setting the LED lamps, the LED lamps in the busy period to maintain strong illumination, automatic dimming began in the middle of the night when the car is little, the LED lights keep low illumination lighting. Overall, the main advantage of intelligent control LED street lamp is a substantial reduction in consumption.

Of course, not only LED lights need to have dimming function, other LED lighting applications in various fields are also required to be dimming function. Basically, the LED is the most effective way to adjust the LED output brightness using a constant current mode. The method can be divided into two types of analog (Analog) current regulation and pulse width modulation (Pulse-WidthModulation, PWM).

Dimming mode can be divided into two kinds of simulation and PWM

First of all, the analog dimming mode is used to adjust the current size of the LED to adjust the peak current to achieve different brightness adjustment. For example, by reducing the forward current of half LED, half the brightness can be obtained. But this will cause the LED peak wavelength (PeakWavELength) or color shift (ColorShift) phenomenon. Moreover, the pulse width modulation (PWM) dimming technology is the use of continuous switching ON and OFF method to change the LED forward current duty cycle (DutyCycle), which does not change the forward current peak. The method can avoid the problem of peak wavelength or color deviation, and has the function of linear dimming.

In general, PWM dimming can significantly reduce the color change of LED, and there are different levels of brightness, can provide additional logic to establish PWM wavelength.

Analog dimming is a relatively simple circuit, but does not apply to the need for constant color temperature applications. On the other hand, it is widely used in practical application because of the fast response speed and more precise dimming of PWM dimming. Many semiconductor industry will be related to the demand for PWM dimming launch related drivers IC.

IC (Linear) power product market director TonyArmstrong pointed out that today's LED driver must have a key performance characteristics, that is, the full dimming LED. With high brightness (HB) LED also launched an increase in demand, the corresponding products, such as LT3956 through TrueColor pulse width modulation (PWM) dimming, can provide a fixed LED color in the dimming range in a ratio of three thousand.

The intelligent driver Spaak photoelectric LED lamp

Furthermore, En Zhipu (NXP) in the LED light field is a masterpiece, the company has launched a light adjustable LED solution SSL2101 switch mode power supply for a small size (SMPS) IC controller, designed for the LED device driver design, and provide a dimming capability. SSL2101 can drive a variety of different power requirements of the lighting system, including LED modified lamps, LED module, LED spotlight, spotlights and LED lights used in store display. The company said, NXPSSL2101 is fully compatible with the lighting infrastructure, can be directly used rectifier power according to the phase modulator, and a high voltage power switch, can be directly from the rectifier voltage start, eliminating the need for external start circuit. To support dimming, the SSL2101 also includes two integrated high voltage switches