1, LED fluorescent lamp constant power
Determine the characteristics of the semiconductor LED influenced by the environment , such as temperature , LED current will increase ; voltage increases, the LED current will increase. Long-term than the rated current work , will greatly shorten the LED life. The LED is constant when changing environmental factors such as temperature and voltage , constant current to ensure that their work .
2, LED fluorescent lamp power to how we can match the light board ?
Some customers to design light board , find the power , find it difficult to have a proper power supply, or too much current , the voltage is too small ( eg I> 350mA, V <40V); either current is too small , the voltage is too high ( eg I < 40mA, V> 180V), resulting in a severe fever , inefficient , or the input voltage range is not enough. In fact , choose a string and pick the best way , plus the voltage and current on each LED is the same, but the effect of the power supply was able to play the best performance. The best way is to communicate and power supply manufacturers , tailored.
3, LED fluorescent lamp power supply current is how much work is the most appropriate?
General LED rated operating current 20 mA , and some plants used to make the outset , design 20 mA , in fact, this current work under very severe fever , after numerous comparison test , designed to be 17 to 19 mA is relatively ideal design for the recommended 18 mA.
4, LED fluorescent lamp power supply operating voltage is how much?
General LED 's recommended operating voltage is 3.0-3.5V, tested, most of the work at 3.125V, 3.125V calculated according to the formula so reasonable . M lamp beads series total voltage = 3.125 * M
5 , series-parallel LED light board with wide voltage How wide do you want ?
For LED lamp in a relatively wide range of input voltage range ( full voltage ) AC85 ~ 265V, the light board parallel LED strings is very important . Due to the current power generally non -isolated step-down power , wide voltage requirements , the output voltage does not exceed 72V, the input voltage range of 85 ~ 265V can be reached . That is, the serial number no more than 23 strings. Do not count too much in parallel , otherwise the operating current is too large, severe fever , and is recommended for 6 /8 and / 12 and . Total current does not exceed 240 mA as well. There is also a wide voltage solution is first with L6561/7527 raise the voltage to 400V, then the buck , the equivalent of two switching power supply, costs twice as expensive , this program cost is not high , there is no market .
6, LED series parallel relationship with PFC power factor and wide voltage is what ?
PFC power supply on the market at present , there are three cases: one is dedicated circuit without PFC , the PFC is generally about 0.65 ; one is with a passive PFC circuit, the light board horses prepared well , PFC generally about 0.92 ; also is active with an active 7527 / 6561 circuit do , PFC can reach 0.99 , but the cost of this program twice as expensive than the second solution. So many second program. For passive PFC circuit : Also called a valley-fill PFC circuit , the operating voltage range is half the peak voltage of the AC input . If the input is 180V, the peak is 180 * 1.414 = 254V, is half the peak voltage 127V, a step-down pressure minus 30V, the maximum output is 90V, so the maximum number of series LED lamp strings 28 . Therefore, to obtain relatively large power factor, the number of lamp beads series not too much, otherwise, it can not reach the low voltage requirements.
7, LED fluorescent lamp power supply current precision how much would be the most appropriate ?
Precision constant current power supply on the market and some of the bad , as the popularity of the program , such as constant PT4107/HV9910/BP2808/SMD802 programs error of ± 8% or ± 10%, constant error is too large . General requirements ± 3% on it. Error of 3% , 6 parallel , each of the error is about ± 0.5%, if the 12-way parallel , each of the error is about ± 0.25%, the accuracy is sufficient. Accuracy is too high , the cost will be greatly increased. And in terms of LED , 17 mA and 17.5 mA little effect.
8 , isolated / non-isolated
Generally made of isolated power as 15W, LED lamp placed inside its transformer bulky , difficult to put out. Especially for T6/T8 lamp, almost impossible, so generally only be isolated 15W, 15W rarely exceeded , and the price is very expensive . So the cost is not high isolation , generally non -isolated more mainstream , the volume can be made smaller , the minimum height 8 mm can be done , in fact , non-isolated safety measures well, the problem does not exist .
9, LED fluorescent lamp power efficiency
Output power ( output LED voltage * Output current / input power ) . This parameter is particularly important if inefficient means a large part of the input power is converted into heat comes out ; If it is installed in the lamp will produce a very high temperature , coupled with a light efficiency of our LED than the distribution of heat , the temperature will be higher superposed . And we supply all the electronic components inside the life will be shortened with increasing temperature . So efficiency is the most fundamental life decision power factor , efficiency can not be too low, or the power consumed in the heat too . Generally above 80% can, however , about the efficiency and light board matching connection.
10, LED fluorescent lamp power Size
Height is the main factor limiting , generally used for T6 tube / T8 size requirements can not be too highly ≤ 9 mm. T10 tube height ≤ 15 mm. Length can be rather long and easier to heat .
EMAIL US
SKYPE