What are the other five questions for the design of the LED tube light

1.What is the  relationship between PFC power factor and wide voltage of LED series-parallel?

There are currently three kinds of PFC power supply on the market: one is dedicated circuit without PFC, the PFC is generally about 0.65; one is with a passive PFC circuit, the light board match well, the PFC is generally about 0.92; there is PFC power supply with an active 7527/6561 circuit, which can reach 0.99, but the cost of this program as twice expensive as the second solution. So as The secondary program. For passive PFC circuit，which is also called a valley-fill PFC circuit, the operating voltage range is half of the peak voltage of the AC input. If the input is 180V, the peak is 180 * 1.414 = 254V, the half of the peak voltage is 127V, a step-down pressure minus is 30V, the maximum output is 90V, so the maximum number of series LED lamp is 28 strings. Therefore, to get relatively large power factor, the number of lamp beads series should be not too much, otherwise, it can not reach the low voltage requirements.

   

2, how much current precision of power supply of LED tube T5 and T8 would be the most appropriate?

some of precision constant current of power supply on the market is too bad, such as the popularity of the constant program, including PT4107/HV9910/BP2808/SMD802 programs whose deviation is ± 8% or ± 10%, the constant deviation is too large. General requirements is ± 3%. Deviation is 3%, for the 6 parallel, each of the deviation 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, 17 mA and 17.5 mA make little effect on LED.

3, isolated / non-isolated

The transformer of 15W isolated power placed inside LED tube T5 and T8 is generally bulky, it is difficult to put into the tube. Especially for T5/T8 lamp, so the LED tube T5 and T8 with isolated power is generally 15W, those exceeding15W are rarely, and the price is very expensive. So the cost of LED tube T5 and T8 with isolation power is not high, the non-isolated is generally more mainstream, the volume can be smaller, the minimum height is 8 mm.

4, power efficiency of LED fluorescent lamp

Output power (output LED voltage * Output current / input power). This parameter is particularly important，low inefficient means a large amount of the input power is converted into heat; If the power supply is installed in the lamp，which will produce a very high temperature, the temperature will be higher superposed. And the lifespan of electronic components inside the LED tube T5 and T8 will be shortened with increasing temperature. So efficiency is the most fundamental factor, deciding the life，the efficiency can not be too low, or the heat generated by power in too much.

5, power of LED tube T5 and T8

Height is the main limiting factor, the power generally used for T5 tube / T8 can not be too highly, which is ≤ 9 mm.Browsing http://www.lead-lighting.com/led-tube/t5-tube-smd-3014-series.htm for more information about LED tube T5.

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