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Grasp the LED lighting design key implementation emotional appeal
2014-03-27 17:17:28

Grasp the LED lighting design key implementation emotional appeal

First:LED the emergence of broke the traditional design method of the light source and the train of thought, there are two kinds of the latest design concept

1. Lighting:In 2008 by philips lighting,To the environment demand to design the lamps and lanterns.Lighting in place as a starting point,aims to create a beautiful, brilliant lighting conditions,To foil scene effect,Make the person feel has the scene atmosphere.

2. Emotional appeal lighting:Is put forward by k euro 2009 mood lighting,To the need of people to design the lamps and lanterns.Mood lighting is emotionally as a starting point,from the perspective of people to create a kind of artistic conception of light environment.mood lighting and lighting is different,Mood lighting is dynamic, lighting system can satisfy the spiritual needs of people,make the person feel the emotional appeal;The lighting is static,it can only be emphasized the need for scene illumination, but cannot express the person's mood,in a sense, emotional appeal lighting lighting.mood lighting contains four aspects: one is the environmental protection and energy saving, 2 Is health,3 it is intelligent,4 it is human nature.

Two:If you want to do the LED lighting design key to efforts in the following respects

1, do not use a bipolar power devices

Doug Bailey pointed out that due to the bipolar power devices, cheaper than the MOSFET,Is generally 2 cents a,So some designers in order to decrease the cost of the LED driver using bipolar power devices,This will seriously affect the reliability of the circuit,Because of increase in the temperature of the LED driver circuit boards, effective working range of bipolar devices quickly narrow, it leads to device failure during temperature rise which affect the reliability of LED lamps and lanterns,The right thing to do is to choose MOSFET device, the service life of the MOSFET device far longer than bipolar devices.

2, don't choose MOSFET voltage 600 v

The withstand voltage of 600 v MOSFET is cheaper,Many think the LED lamps and lanterns of input voltage is 220 v, so the withstand voltage of 600 v is enough,But most of the time circuit voltage to 340 v,When a surge of 600 v MOSFET is easy to breakdown, which affects the service life of LED lamps and lanterns,Actually choose 600 v MOSFET may save some cost but the pay is the price of the whole circuit board,So, do not choose "600 v voltage of MOSFET, had better choose more than 700 v voltage MOSFET," he stressed.

3, try not to use electrolytic capacitor

What do you want to use in LED driver circuit capacitors?Currently have supporters and opponents, proponents argue that if temperature control circuit board can be good, the purpose of, in turn, to extend the life of the electrolytic capacitor, such as selection of 105 degrees of life of 8000 hours of high temperature electrolytic capacitor, according to the passage of the electrolytic capacitor life estimation formula of "every 10 degrees below the temperature, double life", then its working life in a 95 - degree environment for 16000 hours, the working life of 32000 hours in a 85 - degree environment, the working life of 64000 hours in a 75 - degree environment, if the actual working temperature is lower, so life will be longer!It seems that as long as selects high quality electrolytic capacitor is no influence to the life of the drive power!
From no electrolytic capacitor and supporters say the high ripple current caused by the low frequency blinking may cause physical discomfort for some human eyes, the magnitude of low frequency ripple can also lead to some digital camera equipment appear difference frequency flashing light dark grid.So, high quality light lamps and lanterns or need electrolytic capacitor.But opponents think electrolytic capacitor will natural aging, in addition, the temperature of the LED lamps and lanterns is very difficult to control, so the service life of electrolytic capacitor will reduce, which affect the service life of the LED lamps and lanterns.
Explanation, famous people in the industry, in the LED driver circuit input portion can be considered without electrolytic capacitor, actually use PI LinkSwitch - PH will save electrolytic capacitor, PI of single-stage PFC/constant current design can save you big capacity, designers in the output circuit, high voltage ceramic capacitors can be used in place of the electrolytic capacitor to enhance the reliability, some people in the design of two-stage circuit, the output using a 400 v electrolytic capacitor, this will seriously affect the reliability of the circuit, recommended single-stage circuit with ceramic capacitors.For not too concerned about the dimming function, high temperature environment and industrial applications require high reliability, electrolytic capacitor design is not recommended.

4, try to use integrated MOSFET

If the design of high power LED lamps and lanterns is not, it is recommended to use integrated LED the MOSFET drive products, because it has the advantage of integration on resistance of mosfets, less heat to score less,In addition, is the integration of the MOSFET is the controller with the FET,Usually have shut off function, overheat in MOSFET overheat automatically shut off the circuit to achieve the purpose of protection of LED lamps and lanterns, the LED lamps and lanterns is very important, because the LED lamps and lanterns is generally very small and difficult to air cooling

5, try to use single stage structure circuit

If PFC efficiency is 95%, and the efficiency of the DC/DC part is 88%, the efficiency of the whole circuit will be reduced to 83.6%.PI LinkSwitch - PH device at the same time the PFC/CC controller, a 725 V MOSFET and MOSFET driver is integrated into a single package,To upgrade the efficiency of the drive circuit to 87%.However, such a device can greatly simplify the circuit board layout design, can save most traditional isolation used in the design of the flyback type 25 components.Save the components including high voltage large capacity electrolytic capacitor and light coupling device.LED a two-level architecture is suitable for the second constant current drive circuit must be used to make PFC drive LED constant current old drive.These designs have been out of date, no longer cost-effective, so in most cases all had better use single stage design.led lighting


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