LED drive power supply technology development trend

As a kind of new light source, close to the LED power supply and drive circuit with fluorescent electronic ballasts, LED drive circuit's main function is to convert ac voltage to dc voltage, and at the same time to complete the matching of voltage and current with LED. As plummeting silicon integrated circuit power supply voltage, LED working voltage are increasingly in the best range of output voltage, most IC for low voltage power supply technology are also applies to leds, especially the high power LED power supply. Moreover, LED power supply also should be able to take advantage of low voltage IC power production gradually rising economies of scale.

a, LED the power driving circuit and main technical overview

1)

power supply voltage transformation technology is LED light source reliability and adaptability of an important part of must be priority consideration. Current grid is 220 v alternating current (AC), and the LED light source is a semiconductor light source, usually with a low voltage dc power supply, this requires a set or external AC - in the lamps and lanterns DC conversion circuit, to adapt to the characteristic of LED current drive. Current power supply ways to choose a switch power supply, high frequency power supply, after capacitance step-down rectifier power supply, etc, according to the current stability, transient overshoot as well as the safety and reliability of different choices for different requirements.

　　2) The power and the life of the drive circuit and cost

the LED life, although the single LED itself life 100000 hours, but its application must match the power conversion circuit, so the LED lighting appliance whole life must from optoelectronic integrated application into consideration. But for LED lighting, to match the requirements, the power and the life of the drive circuit must be more than 100000 hours, make it become the bottleneck of the LED lighting system no longer factors. Considering the long life and don't add too much cost, power supply and the life of the drive circuit and cost usually should not exceed one third of the total cost of the lighting system, in the early stages of the product development of led lighting lamps and lanterns, must balance the good relationship between the power and the life of the drive circuit and cost.

　　3) Driver programmable technology

LED is used as the light source is a remarkable characteristic is under the condition of low drive current can still maintain its lumen efficiency, at the same time for R. G。 B。 Type polycrystalline mixed to form white light, the light through the development of a digital RGB hybrid control system for the LED, enabling users to in large range of LED brightness, color and color adjusted, give a person with a kind of brand-new visual enjoyment. In urban landscape lighting applications, LED light source can be under the microprocessor control can change according to different pattern, form night spectacular provide dynamic effect, relative to other LED light source is reflected in this respect will be a unique competitive advantage.

　　4) The efficiency of power supply and drive circuit

the LED power supply and the driving circuit, should not only have certain close to constant current for LED the forward current output, and high conversion efficiency, electro-optic conversion efficiency is an important factor of LED lighting, or you will lose the advantages of LED energy saving, the commercialization of switch power supply, its efficiency is about 80%, as the LED lighting power supply, its conversion efficiency will be further ascension.

2, the technology development trend

1) According to the characteristics of the LED development a series of constant pressure constant current control electronic circuits, using integrated circuit technology will each LED on the best current value of the input current control LED to the stability of the current, flux and generate the highest output. LED drive circuit in the input voltage and ambient temperature change under the condition of best can control the size of the LED current.

　　2) LED drive circuit has the function of intelligent control, the LED load current can be under the influence of various factors can be controlled in advance design level. When the load current changes caused by various factors, the primary control IC can control switch on the load current back to the initial design value.

　　3) In terms of control circuit circuit design, to the centralized control, standard modular, development system scalability three aspects.

　　4) In the current LED lighting and flux under the condition of limited, give full play to the LED colour diversity, the characteristics of development of color changing LED lighting control circuit. To assist the

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