1, what is the LED driver power supply?
        LED drive power supply the power supply is converted into a certain voltage current to drive the LED voltage converter, normally: LED drive power supply input, including high voltage ac power frequency (mains), low-voltage dc, high-voltage direct current, low voltage high frequency ac (such as the output of electronic transformer).And the output of the LED driver power supply are mostly can change with LED positive pressure drop values and change the voltage of the constant current source.LED core components including power switch controller, the inductor, switch components (MOSfet), the feedback resistance, input filter, output filter parts, etc.In accordance with the requirements of different occasions, also have input over-voltage protection circuit, input under-voltage protection circuit, LED open circuit protection, over current protection circuit, etc.
2, the characteristics of the LED drive power supply
(1) high reliability
        Especially like the LED street lamp driver power supply, in a high altitude, maintenance is not convenient, the cost of maintenance is also big.
(2) high efficiency
        LEDs are energy saving products, drive power efficiency is higher.For the power supply installed in the lamps and lanterns and heat dissipation is very important.Power supply of high efficiency, its power consumption is small, in the lamps and lanterns of calorific value is small, also lower the temperature of lamps and lanterns.Good for delaying the LED light failure.
(3) the high power factor
        Power factor is the requirement of load of power grid.Generally below 70 watts of electrical appliances, there is no mandatory indicators.Though the power of a single use lower electric power factor, the impact on the grid is not big, but the use of large amount of lighting at night, the same load is too concentrated, can produce serious pollution to grid.For 30 ~ 40 watts of the LED drive power supply, it is said that in the near future, may be the index of power factors have certain requirements.
(4) drive way
        Popular now have two kinds: one is a constant voltage source for multiple constant current source, each constant-current source separate for each LED power supply.This way, flexible combination, LED failure all the way, don't affect the work of other leds, but the cost would be slightly higher.The other is a constant current power supply is directly "zhongke hui bao" change driven by the way, the LED series or parallel operation.It has the advantage of low cost, but poor flexibility, but also solve a LED failure, does not affect other LED running problem.These two forms, for a period of time.Multi-channel constant current output power supply way, in terms of cost and performance will be better.Maybe the mainstream direction of the future.
(5) surge protection
        LED the ability of anti surge is relatively poor, especially the reverse voltage resistance.Strengthening the protection is also very important.Some LED lights installed outdoors, such as the LED street light.As a result of the power grid load and sling and lightning induction, into the various surge from the grid system and some surge can cause the damage of the LED.Therefore the driving power of analysis "zhongke hui bao" in surge protection should have certain lack of, and as for the power supply and frequent replacement of lamps and lanterns, LED drive power to suppress surge intrusion, protect the LED is not damaged.

(6) protection function
        Power supply in addition to conventional protection function, it is better to add the LED temperature in the constant current output feedback, prevent LED temperature is too high;To conform to the requirements of safety and electromagnetic compatibility.

3, According to the drive mode classification
(1) the constant flow
        Constant current drive circuit of the output current is constant, and the output dc voltage is different as the size of the load resistance within a certain range, load resistance is small, the output voltage is low, the greater the load resistance, the higher the output voltage.
        Constant current circuit is not afraid of load short circuit, but it is forbidden to load completely open;
        LED constant current drive circuit drive is ideal, but relatively high prices;
Should be paid attention to by using maximum current and voltage, it limits the number of using leds.
(2) voltage type
        When the voltage regulation circuit, to determine the various parameters of the output voltage is fixed, and the output current is as the load increase and decrease and change;
        Regulating circuit is not afraid of open load, but it is forbidden to load completely short circuit;
        With voltage driving circuit to drive the LED, each string need to add the appropriate resistance can make average a string of LED display brightness;
Affected by the rectifier voltage variation of brightness.
4, the integral constant current and constant current by road works advantages and disadvantages
        Compared with integral constant current, although constant current shortcomings more by road, has a high cost.But it can really protect leds and prolong the life of the LED, so by constant current is the trend of the future.
5, LED power supply shortage
        The causes of deficiency of LED drive power supply at present:
        Production of LED lighting and related products of the company's technical staff understanding of switch power supply is not enough, the power supply can be normal work, but some critical evaluation and electromagnetic compatibility of consideration is not enough, still have some hidden trouble;
        Most LED power production enterprises from ordinary transformation come and do the LED power supply, switch power supply for LED characteristics and use of knowledge is not enough;
        About LED standard almost at present, most of them are reference switch power and electronic rectifier standards;
        Now most of the LED power supply is not regulated, so much quantity is small.Small purchase quantity, the price is on the high side, and components suppliers also don't cooperate;
        LED power supply stability, wide voltage input, high and low temperature, over temperature and over voltage protection and other issues are not solved one by one;
        First is driving circuit of whole life, especially the key parts such as: the life of the capacitance at high temperature directly affects the service life of power;
Higher conversion efficiency is the LED driver should challenge, especially when driving high power leds even more so, because all not as light output power as heat dissipation, power conversion efficiency is low, influence the exertion of LED energy saving effect;
        In smaller power (1-5 w) applications, proportion of constant current drive power cost is close to 1/3, is close to the cost of the light source, to some extent, affected the market promotion.