For saving the energy,LED got a lot of promotion,but we need to have a power LED driver,which will directly affect the quality of life of the LED,so it's most inportant thing that how to be an LED driver power supply when you are LED power designer. This article describes some of the LED driver power supplies'problem,and hope to be able to provide a little to help engineers .
1,LED drive circuit directly affect life
We are talking about led drivers include digital and analog drive categories drive,digital drive means driven digital circuits,including digital dimming control,RGB full color changes and so on. Analog driving means driving analog circuits,including AC constant current switching power supply,DC constant current control circuit . Driven by the electronic circuit components,including semiconductor elements,resistors,capacitors,inductors,etc. These components have a service life of any device failure will cause a failure of the whole or part of the circuit is deactivated. LED life is 5-10 million hours,calculated by 50,000 hours,continuous light,nearly six years of life. Switching power supply life is difficult to achieve a six-year,switching power supply warranty period is generally available on the market 2-3 years,up to 6 -year warranty is military power level,the price is 4-6 times the normal power supply,the general lamps Factory is unacceptable . So mostly the fault LED lamp drive circuit malfunction .
2,The heat problem
LED cold light source,operating junction temperature must not exceed the limit,but also left a certain margin design. The lighting is designed to consider the appearance,ease of installation,many aspects of light,heat,etc.,to seek a balance in many factors,so that the overall lighting is the best. Development time is not long LED lamps,can learn the little experience,many designs are constantly improved . Some manufacturers use LED lighting power for the outsourcing or outsourcing,lighting designers know much about the power supply,LED heat to a larger space,the smaller the power of heat to space . Lighting design is generally good and then find a suitable power to support,so give the power to bring some difficulty matching . Often encountered by small lamps inside the interior space or high temperatures,and low cost control,can not be assigned to an appropriate power source. Some LED lighting plant has a power R & D capabilities,at the beginning of the initial lighting design to assess the power of design simultaneously,we can solve the above problems. To be taken into account in the design of the cooling heat and power LED,the overall control of the lamp temperature,so as to design a better lighting .
3,Power supply design problems
a,power design . Although the LED luminous efficiency,but there are 80-85 % of heat loss,causing the lamp inside temperature 20-30 degrees,25 degrees if the ambient temperature conditions,there are 45-55 degrees inside the lamp power for a long time in a hot environment working to ensure that life we must increase the power margin,generally left to 1.5-2 times the margin.
b,component selection . Internal temperature of 45-55 degrees lower lighting conditions,as well as the power supply internal temperature of about 20 degrees,the temperature near the device to reach 65-75 degrees. Some components in high temperature parameter drift,and some life will be shortened,so that the device you want to select,special attention can be used for a long time at a high temperature electrolytic capacitors and wires.
C,the electrical properties of the design . The switching power supply design parameters for the high power led module is mainly constant parameter determines the size of the current brightness of the LED,if the bulk of the current error is large,the brightness of the entire batch of light uniform. And changes in temperature can cause the power supply output current offset . Batch error control is generally within + / -5%,in order to ensure consistent brightness of the lamp . LED forward voltage drop of a deviation,the constant current power supply design voltage range to include LED voltage range. Use multiple LED series,when multiplied by the minimum pressure drop for the lower voltage in series number,series number is multiplied by the maximum pressure drop ceiling voltage,constant current power supply voltage range slightly wider than this range,the general upper and lower limits of each leaving 1-2V margin.
