Due to the surrounding environment has a greater impact on the heat dissipation effect of LED street lights, such as the summer temperature rises, the current of LED street lights increases, the voltage rises, and for a long time exceeds the rated current conditions, it will greatly shorten the service life of LED street lights, and LED constant current is when environmental factors such as temperature and voltage change, to ensure that its working current value is unchanged. Therefore, it can solve this problem, the effect of the radiator LED street lamp power supply, power constant current accuracy LED street lamp market some power constant current accuracy is poor, the market popular LED street lamp recommendation and other programs, error of ±8%, constant current error is too large, the overall requirement of ±3% can be, according to the design plan of 3%, the power of the production department should be fine-tuned to ±3% error.

Led street lamp supply voltage

Led operating voltage is 3.0~3.5V, after testing, most of the operating voltage is 3.2V, so it is more reasonable to calculate according to 3.2V. n lamp bead series total voltage =3.2*N,LED street lamp power supply working current is the most suitable, such as LED rated working current 350 MA, some factories are used up at the beginning, designed 350 MA, in fact, in this current work heat is very serious, after many comparative tests, more ideal is designed to 320 Ma. The heating is minimized, so that more of the electrical energy is visible light energy.

For AC85-265V input voltage range wide LED street lamp power board, if its series parallel and wide voltage to how wide, the LED street lamp power board series parallel mode is very important. As far as possible, do not use a wide voltage, can be divided into AC220V, as far as possible AC110V, to ensure the reliability of the power supply. Another wide voltage scheme, APFC active power compensation, is to first use L6561/7527 to increase the voltage to 400V, and then reduce the voltage to equal the level of two switching power supplies. This plan is only used in exceptional circumstances.

Ordinary isolation power supply such as 15W, placed in the LED street lamp power tube, the volume of the transformer is very large, difficult to place. Depending on the space structure, depending on the situation, the exclusion zone can generally only reach 15W, and after 15W, it is very rare and very expensive. Therefore, the cost performance of the isolator is not high, the general non-isolator accounts for more mainstream, the volume can be made smaller, the minimum can be made 8 mm higher, in fact, the isolator has done a good job of safety measures, there is no problem. The permitted space can also be used to isolate the power supply.

Some customers first design the lamp board, and then find the power supply, found it difficult to have a suitable power supply, or the current is too large, the voltage is too small (7X1WI>350mA, or V<20V); Either the current is too small, the voltage is too high (such as I<200mA,V>25V), resulting in serious heating, low efficiency, or the input voltage range is not enough. In fact, choose one of the best series and connection methods, each LED voltage and current are the same, and the effect of the power supply can play the best performance. It is best to communicate with the power supply manufacturer first and customize according to their requirements. Or make your own electricity.

Series parallel and power factor of light-emitting diodes

The number of lamp beads does not exceed 45 strings of LED street lamp power supply series is appropriate. Therefore, in order to obtain a larger power coefficient, the series number of lamp beads can not be too small, otherwise it can not achieve the best working state, the number of series times on the isolated power supply is related to the number of turns of the secondary winding, the power supply to be achieved must meet the requirements of the output power.

The smaller the operating current of the electronic device at the rated voltage, the longer the life of the bottom, and conversely, the shorter the life of the bottom. Lamp beads are more sensitive to the inductance of LED street lights, and the higher the AC inductance, the worse the lighting comfort.

Electrolytic capacitors are generally used to maintain voltage, minimize the output voltage AC portion, and the capacity of electrolytic capacitors at the bottom voltage is not too small, 1UF<1.5MA of capacity and the ratio of output current otherwise the LED will flash. The non-isolated input of the high-voltage electrolytic capacitor is the same as the isolated input, and the output is 1UF<6MA. The output electrolytic capacitor of the dimming LED power supply is 1UF<0.5MA.

Power supply efficiency of LED lighting fixtures

Particularly important is the value of the input power minus the output power, the greater this parameter, the lower the efficiency, meaning that a large part of the input power is converted into heat energy. Therefore, efficiency is the most basic factor to determine the life of the power supply, the efficiency can not be too low, otherwise it will consume too much energy. The efficiency of the non-isolated type is higher than that of the isolated type, generally more than 80%, however, the efficiency of the isolated type is related to the connection method of the lamp board.