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Then the question is, what chips should be used for LED wall washers? This depends on the requirements of this project. For some government projects, the customer needs are different. They should use the US tax code chip or use US U.S. tax. Chips, for general business units, or hotel lighting, should test the Taiwan imported chips, this price is relatively high, it should be a good choice, of course, there are lower-end, but I am cautious, because it is indeed Not a good result, the light fade is also relatively large, this is not worth the candle, because we have to use the lighting project for a minimum of two or three years, with too bad, one year and a half does not have much meaning.
Cost-effective LED wall washers should have the following characteristics:
Now the market for LED outdoor lighting is still quite chaotic, and the price difference is also very large. The choice of our LED lighting engineering customers is also quite entangled. The price difference of LED wall washers is relatively large, because there are gaps in materials, some are said to be Using a good chip, the actual use is not used in place, because some manufacturers have not so far the problem of filtering, and do not want to be more stable, just earn a single bill, when they are big, they will change a brand and then do Therefore, I feel that it is necessary to do a good job of testing the customer. This is because I am afraid that the customer is giving enough price. The manufacturer will not do it according to the principle. If you do well, you must also look at their qualifications. Is there any success? Case, professional program when talking, so it is easy to distinguish.
1. Matching of LED wall washer power supply and lamp board:
Some customers first draw the light board, then find the power supply, and find that it is difficult to have a suitable power supply, or the current is too large, the voltage is too small (such as I>350mA, V<40V); or the current is too small, the voltage is too high (such as I< 40mA, V>180V), the result is a severe heat, low power, perhaps the input voltage scale is not enough. In fact, picking the best string parallel connection method, the voltage and current applied to each LED are the same, and the power supply can carry out the best function. The best way is to communicate with the power supply manufacturer and tailor it.
2, must be constant flow:
The characteristics of LED semiconductors are determined to be greatly affected by the environment. For example, if the temperature changes, the LED current will be added, the voltage will be added, and the LED current will be added. Exceeding the extra current rating for a long time will greatly shorten the operating life of the LED. The LED constant current is to ensure that its rated current does not change when environmental factors such as temperature and voltage change.
3, LED rated current:
Ordinary LEDs have an additional rated current of 20 mA. Some factories use them at the beginning to draw 20 mA. In fact, the rated heating at this current is very severe. After repeated comparison experiments, the 17 mA is considered to be more ambitious. The total current of the N parallel connection = 17 * N;
4, LED rated voltage:
The recommended voltage rating of ordinary LED is 3.0-3.5V. After testing, most of it is rated at 3.125V, so it is reasonable to calculate according to 3.125V. Total voltage of M lamp beads in series = 3.125* M
5, LED lamp board series and parallel and wide voltage:
In order to make the LED wall washer rated on the AC85-265V scale of the input voltage scale, the LED series-parallel method of the lamp board is very important. Since the current power supply is generally a non-blocking buck power supply, when the wide voltage is requested, the output voltage should not exceed 72V, and the input voltage scale can reach 85-265V. In other words, the number of series does not exceed 23 strings. Do not have too many parallel connections, otherwise the rated current is too large and the heat is severe. The recommended value is 6 and /8 and /12. The total current does not exceed 240 mA. There is also a wide voltage plan, that is, first use L6561/7527 to raise the voltage to 400V, and then step down, which is equivalent to two switching power supplies, the cost is doubled, this plan is not cost-effective, there is no market.