The skills of LED chip selection
2017-05-10 16:10:45
LED as a clean green light source has been widely recognized.LED light source long life, energy saving, simple and convenient application, the use of low cost, and thus in the home lighting will be a massive application. As early as 2007, the global annual home lighting lamp holder shipments of about 50 billion.
LED light source technology matures, the rapid growth of luminous lumens per watt, prompting its annual decline in prices.LED green lighting market and the stability of several years of growing demand will be integrated circuit industry following mobile phones, MP3 after the consumer electronics market super tsunami The LED lamps of high energy, long life, and environmental protection of the superior performance has been generally recognized.
LED high energy: DC drive, ultra-low power (single tube 0.03 ~ 1W) electro-optical power conversion close to 100%, the same lighting than the traditional light source more than 80% energy saving.
2, LED environmental protection: LED is a green light source, better environmental benefits in the spectrum without ultraviolet and infrared, low heat and no flicker, no radiation, and waste can be recycled, no pollution does not contain mercury, cold light source, Can be safe to touch, is a typical green lighting source.
3, LED long life: LED light source is called longevity lamp solid cold light source, epoxy resin package, the lamp body is not loose part, there is no filament light burning, heat deposition, light failure and other shortcomings, the service life of up to 50,000 to 100,000 hours, more than 10 times longer than the traditional light source life.
LED light source work characteristics
The skills of LED chip selection
The skills of LED chip selection
Lighting with LED light source VF voltage is very low, under normal circumstances 2.75 ~ 3.8V, IF is generally 15 ~ 1400 mA. Therefore, the LED driver IC output voltage is VFxN or VFx1, IF keep constant current at 15 ~ 1, 400mA. LED lamps use LED light source with low power (IF 15 ~ 20mA) and high power (IF greater than 200 mA ) Two kinds. Low-power LED used to make LED fluorescent lamps, decorative lights, grille lights. High-power LED is used to make home lighting, spotlights, underwater lights, wall washer, street lamps, tunnel lights, car work lights and so on. Power LED light source is a low voltage, high current driven device, its luminous intensity determined by the size of the current flowing through the LED. Current over the General Assembly caused by LED light attenuation, the current is too small will affect the LED luminous intensity. Therefore, the LED driver needs to provide constant current power supply to ensure the safety of high-power LED, while achieving the desired luminous intensity. In the field of LED lighting, LED lights to reflect the characteristics of energy saving and long life, the right choice LED driver IC is essential. There is no good match between the driver IC, LED lighting advantage can not be reflected.
LED lamps on the low-voltage chip requirements
1, the drive chip nominal input voltage range should meet the DC 8 ~ 230V, to cover a wider range of application needs. The pressure resistance is preferably greater than 45V. When the input is AC 12V or 230V, the simple bridge rectifier output voltage will fluctuate with the grid voltage, especially when the voltage is high, the output DC voltage will be high. If the driver IC does not have a wide input voltage range, it will often be in the grid voltage will be breakdown, which burned LED light source.
2, the driver chip nominal output current requirements greater than 1.2 ~ 1.5A. As the lighting of the LED light source, 1W power LED light source of the nominal operating current of 350mA, G4 LED 3W power LED light source of the nominal operating current of 700 mA. Power LED light source needs more current, so LED lighting selection of the driver IC must have enough current output, the design of the product must also make the driver IC at full load output of 70 ~ 90% of the best work area. The use of full load output current driver IC in the narrow space of light cooling poor, easily lead to lamp fatigue and early failure.
3, the driver chip output current must be kept constant, so that LED can be stable light, not flashing. The same batch of driver chip in the same conditions, the output current size to be as consistent as possible, that is, discrete small, so that in the production of large quantities of automated production line to ensure effective and orderly. For the output current has a certain discrete drive chip, must be in the factory or put into the production line before the sub-picking, adjust the PCB board current set the resistance of the resistance size, so that the production of LED lamps constant current drive plate on similar LED The luminous brightness of the light source is consistent to maintain the consistency of the final product.
