LED fluorescent power is a very important part of th […]
LED fluorescent power is a very important part of the LED fluorescent lamp, if the choice of improper, LED fluorescent display can not play his proper function, and even may not be able to use the normal lighting. To make LED fluorescent lamp work in a wide range of input voltage range AC85 ~ 265V, then the light board LED string parallel way is very important. In other words, the number of series does not exceed 23 strings. The number of parallel not too much, otherwise the working current is too large, severe fever, recommended for 6 and / 8 and / 12 and.
LED drive power manufacturers are mainly divided into three major types: the first is to do the development of LED chips or LED lights factory, homeopathic to the downstream osmotic oozing; the second category is to do the original lighting is the factory; the third category is completely new Open factories, they used to do power or other products or new businesses. General LED recommended working voltage is 3.0-3.5V, tested, most of the work in the 3.125V, so by 3.125V formula is more reasonable. M lamp beads in series with the total voltage = 3.125 * M. Long over the rated current work, will greatly shorten the life of the LED. The LED constant current is in the temperature and voltage and other environmental factors change, to ensure that its working current unchanged. The total current does not exceed 240 milliamperes as well.
Choose a best string and parallel way, plus the voltage and current on each LED is the same, and the power of the effect is able to display the best function. There is also a wide voltage program, that is, first with the L6561 / 7527 voltage elevation to 400V, and then buck, equivalent to two switching power supply, the cost of double, this program is not high cost, no market. LED semiconductor characteristics determine its impact by the environment, such as temperature, LED current will increase; voltage increases, LED current will increase. The best way is to first communicate with the power supply manufacturers, tailor-made. Currently there are three kinds of power supply PFC on the market: one is not with PFC dedicated circuit, the PFC is generally around 0.65; one is with a passive PFC circuit, light board well, PFC is generally around 0.92; also With a kind of active active 7527/6561 circuit to do, PFC can reach 0.99, but the cost of this program than the second solution is twice as expensive.
General LED rated working current of 20 milliampere, and some factories started to use, designed 20 milliamperes, in fact this work under the current fever is very severe, after repeated comparison test, designed to 17 ~ 19 milliamperes is more Ideally, the recommended design is 18 milliampere. Because the current power supply is generally non-isolated step-down power supply, in the requirements of a wide voltage, the output voltage should not exceed 72V, the input voltage range can reach 85 ~ 265V. (Such as I> 350mA, V <40V); either the current is too small, the voltage is too high (such as I <350V), the current is too small, the voltage is too high (such as I < 40mA, V> 180V), the result is a severe fever, low efficiency, or the input voltage range is not enough.