LED lighting industry, lighting lighting project is well received by the global environment, the industry also has its particularity. The LED lamp power is precisely the most important development of the current LED for LED technology related to the design, there are already a variety of programs and unique design approach, we come one by one to find out.
1. LED lamp power supply constant Why must it?
Characteristics of LED lighting
material determines its influenced by the environment, such as elevated temperature, LED current increases, the voltage increases, the LED current will increase. Long-term than the rated current work, will greatly shorten the life of the LED lamp beads. And that is when LED constant current and voltage changes in environmental factors such as temperature, to ensure that their operating current value unchanged.
2. LED lamp power supply current precision
Precision constant current power supply on the market, some of the difference, as the popularity of the recommended programs constant program error of ± 8%, constant error is too large. ± 3% generally require it. 3% of the design. To fine-tune the production of power in order to achieve ± 3% error.
3. LED lamp power supply operating voltage
General LED's recommended operating voltage is 3.0-3.5V, has been tested, most of the work at 3.2V, 3.2V is calculated according to the formula so reasonable. N-series lamp beads total voltage = 3.2 * N
4. LED lamp power supply operating current is how much is the most appropriate
Such as LED's rated operating current 350 mA, and some plants used to make the outset, designed 350 mA, in fact, this current work is very serious fever, after numerous comparison test, designed to be 320 mA is ideal . Minimize the amount of heat, so that more energy can become visible.
5. LED street light series and parallel with the wide voltage power supply board how wide do you want?
For LED lights power supply input voltage range is wide range AC85-265V, the LED lamp series and parallel plates is very important. Try not to use a wide voltage, can be divided into AC220V, AC110V classification possible, so as to ensure the reliability of the power supply. Due to the current supply is generally a non-isolated step-down constant current power supply, requiring voltage 110V, the output voltage should not exceed 70V, serial number no more than 23 strings. When the input voltage is 220V output voltage can reach 156V's. That is, not more than 45 number of series strings. Parallel number not too much, otherwise the operating current is too large, the power severe fever. There is also a wide voltage scheme, APFC active power compensation is first with L6561 ($ 0.4083) / 7527 of the voltage is raised to 400V, then the buck, the equivalent of two switching power supply. This program under certain conditions before using.
6. Isolated / Non-Isolated
Generally made of isolated power as 15W, the power LED lights
placed inside the tube, the transformer bulky, difficult to put in here. Mainly depends on the spatial structure, as the case may be, the general isolation can do 15W, 15W rarely exceeded, and the price is very expensive. Therefore, the isolation of cost is not high, the general non-isolated more mainstream, the volume can be made smaller, the minimum can be done 8 mm high, in fact, non-isolated security measures well, is not problematic. Space allows isolated power can do.
7. LED lamp power supply must match how it can be done with light bead board?
Some clients to design a good light board, find the power, find it difficult to have the appropriate power, or too much current, the voltage is too small (eg 7X1WI "350mA, or V" 20V); or the current is too small, the voltage is too high (eg I "200mA or V" 25V), resulting in a severe fever, inefficient, or not enough input voltage range. In fact, choose a best string and joints, increase in the voltage and current on each LED is the same, but the effect of power able to play the best performance. The best way is to communicate and power supply manufacturers, tailored. Or their own power production.
8. LED strings in parallel with PFC power factor
Isolated high-side input AC220V electrolytic capacitor input power capacity generally 1W = 1UF, AC110V1W = 2UF PFC power supply on the market at present, there are three cases: one is without power factor correction PFC without a dedicated circuit, the PF value is generally 0.65 about; two is a passive power factor correction PFC circuit, which is a passive power factor correction lights, also known by the current board is currently the most widely used best reliability, PF value is generally about 0.92; also in three 7527/6561 with active active circuit to do, that is, active power factor compensation, called the APFC circuit AC220V, AC110V electrolytic capacitor can be used the same capacity, the choice of 1W = 1.5UF. PF value up to 0.99, but the cost of this program twice as expensive than the second scenario slightly worse reliability. So the second scenario more useful. For passive PFC circuit: Also known as valley fill PFC circuit, the DC operating voltage range of the AC input voltage peak half. If the input is 220V, the peak is 220 * 1.414 = 312V, half the peak voltage is 156V, in a non-isolated on the basis of the output waveform for the half-wave no next half-wave.
Therefore, the power LED lights up to the number of beads in series strings below 45 is appropriate. Therefore, to obtain relatively large power factor, the number of lamp beads series not too little, or fail to achieve the best working conditions in the isolated power number and serial number of the secondary winding turns much information, it must be done Power to meet the output power. Electronic components within the rated voltage range operating current smaller heat the bottom longer life, life will be shorter and vice versa. AC power LED lights bead weight is very sensitive to exchange higher light weight comfort worse. Generally use an electrolytic capacitor to maintain the voltage, the output voltage of the AC minimize weight, the bottom end of the electrolytic capacitor voltage capacity can not be too small, the capacity and output current proportional to 1UF "1.5MA otherwise LED will flicker. Non-isolated inputs and isolated high voltage capacitors choose the same type, the output capacitor selection 1UF "6MA. Dimming LED power at the output of electrolytic capacitors to meet 1UF "0.5MA.
9. LED lamp power supply efficiency
Input power subtracts the output power value, this parameter is particularly important, the lower the value the greater the efficiency, it means that a large part of the input power is converted to heat that comes out; if it is installed in the lamp will produce a very high temperature , combined with our LED light efficiency than a heat emitted, it will produce a higher temperature superposition. And we all electronic components inside the power supply life will be shortened with increasing temperature. So that the power efficiency is to determine the life of the most fundamental factor, efficiency is too low, otherwise the power consumed in the heat too. More efficient than non-isolated isolated, usually more than 80% can, however, about the efficiency of the matching light board connection
10. LED street lamp power supply cooling
The main factor is the cooling solution Power LED lights beads in hot conditions but can greatly extend the life, usually with aluminum and easier to heat. That is, the power LED lights beads attached to the aluminum plate, external to maximize heat dissipation area.
Faced with such a vast LED market is really full of vigor, mainly to develop scientific, can achieve a leading position on a few technical areas, I believe that China's LED business will become more powerful.