Technical communication: the isolation of LED fluorescent lamp power supply options

With LED Green concept of continuous implementation of domestic LED high bay lights market is gradually warming. At the same time the price factor of this development has become a major bottleneck. Domestic manufacturers have to reduce costs, non-isolated power supply slowly become the dominant domestic market. In the choice of non-isolated power supply in order to save costs when buyers and sellers to brag about products, making the whole market chaos.
        Fluorescent power is divided into two major categories of isolated and non-isolated, isolated power supply isolation scheme advantage of his good stability, anti-interference ability sense, security is relatively easy to control, but the cost is relatively high, generally speaking isolated power output load range of 30-42V. Non-isolated power efficiency advantage is that he is easy to do high (above 90%), the overall heat a small, normal operation power devices (MOS pipe, power inductors, etc.) the temperature can be controlled at around 40, has done a relatively high power output adaptability strong, with load can range from 30-84V. Select the number of  LED high bay lights manufacturers in the power supply when the overall adaptability are required in order to adapt to the full voltage power supply 90-265V input, load range requirements up to 84V, so the choice is there are certain risks and hazards. This is a lot of power supply manufacturers overlooked a problem, claiming full voltage input. Prevalent in the market today are mostly non-isolated solutions Active PFC PSR program, such programs are mostly buck topology (BUCK), a typical scenario for the (Si Cenda, green up). The other is passive PFC solutions, such programs also for the buck topology (BUCK), a typical scenario is (Jing Feng, duty cycle).BUCK circuit is a step-down chopper circuit, the average output voltage Uo buck topology is always less than the average input voltage Ui, usually have continuous current through the inductor, depending on the switching frequency, the filter inductor and capacitor. Typically require relatively BUCK circuit output voltage and the input voltage has a certain pressure, usually require more than 30V, that in order to make full voltage 90-265V input, 55V output voltage requirements in the following, otherwise there will only be lighting, electrical parameters such as abnormal security risks.

     The following selected two typical parameters do comparison, we can clearly see. Experiment chose two different companies supply an as **** technology, another one is a larger market volume company.
Experimental one, as **** Ltd. T002 series, nominal operating range of AC :160-265V DC :30-84V Imax = 270mA, the following experiments the normal operating voltage range input for non-state

     Experiment ⅠTest Record Sheet These test data table it is clear that, when the power supply load is 76V (24 strings), the input voltage is 90-110V time, THD, current and other parameters have a very significant volatility, 90V input when the power constant loss of function, with a difference of nearly normal operating current 70mA, harmonic currents as high as 40.51%, on the whole effect of light lumens have a dramatic effect.

      Whether it is because of the design aspects of the factors leading to the phenomenon? The experiment also found a large market share in the power of similar parameters, programs for the BUCK circuit with the power supply nominal operating range of AC :90-265V DC :30-84V Imax = 280mA, nominal operating power for the second experimentwithin the scope of the test data
Experiment II Test data From the measured data is also very clear that the power supply in response to a load of 82V (24 strings), the input voltage of 90-110V also exists when an experiment mentioned risks, if some of the power supply manufacturers in order to reduce costs, the inductor using EPC13, there is high temperature after core saturation and other safety hazards.
Such BUCK circuit in the end what kind of circumstances can truly meet the full voltage input it? Experiment III as **** Technology T002B series, nominal operating range of AC :90-265V DC :30-52V Imax = 330mA
Experiment Ⅲ Test data As can be seen from the above experiment, when the load voltage is 52V, when the power supply to the full voltage range, the parameters to achieve the required value.
Through the above three experiments can be drawn, in the choice of non-isolated power supply, the first thing you should ask is what kind of power supply manufacturers that supply the program, if the program will have to buck BUCK carefully selected voltage input when required to do all the time certain requirements with load voltage and the minimum input voltage is greater than 30V voltage difference, since some lighting companies lack of experience in the power test, resulting in a look at whether the light, do not look at the chaos in electrical parameters, resulting in a certain time delivery Clients frequently appears after power corrupt adverse effects. In this appeal to all the  LED high bay lights industry practitioners can uphold the principle of quality first, the real advantages of LED energy-saving, and ultimately promote the healthy and sustainable development for the benefit of society!


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