F.A.Q

LEDs are comprised of 3 main components: the LED’s (the chip set that produces light), the driver (converts AC to DC) and the heat sink (to keep everything cool).Our lighting product series up to 50 watt also available without additional driver, Driver on board,  also LEDs take DC power from the driver and create light. The heat sink captures heat from the LEDs and the drivers. Although LEDs produce significantly less heat than the light bulbs we have been used to over the past century, the heat they produce must be managed. The better this is done, the longer the life of the product. LEDs also performs the job of converting electricity to light more efficiently than other light sources, that is why we can replace a 65W incandescent light bulb with a 12W LED bulb.

There are many benefits. Here is a list of a few:
    a. an immediate reduction in your electricity bill.
    b. Less heat. LED fixtures are extremely efficient converting electricity into light.
    c. LED Bulbs last a very long time, from 30,000 to 200,000 hours.
    d. They are virtually indestructible.
    e. They do not contain mercury or other hazardous materials
    f. highly recyclable – with no hazardous parts, you can easily reclaim most of the parts in an

        Environmentally safe way.

It all depends what you are converting. Incandescent to LED, fluorescent to LED, Metal Halide to LED. Fortunately, we built a very simple and information Energy savings calculator. Enter in a few fields or select one of our existing energy savings scenarios, and let it calculate your energy savings. We tried to make it simple and easy to use.           

Yes and No. First, not all LEDs are dimmable. The driver must be designed to allow dimming. Secondly, you must purchase the right type of dimmer. Most retail stores now carry dimmers specifically designed for LED bulbs. Please note, if you purchase a non-dimmable LED bulb and try to dim it, it will cause the bulb to fail and also void the warranty. Some of our industrial and commercial LED fixtures (high bays, floods, area lighting, and retrofits) work with a 0-10V dimming system. 0-10V dimming requires special wiring and a special type of dimmer.

No, LED bulbs do not contain mercury or any other hazardous metals or chemicals. CFL’s and fluorescents do contain a very small amount of mercury that needs to be disposed of correctly. So when your LED bulb eventually stops to work, you don’t have to worry about costly or special disposal procedures.

Color temperature for light bulbs is measured on the Kelvin scale. LED Bulbs come in a variety of colors, but the most common are in a range from 2700K to 7500K. The unfortunate thing is that the only consistent measurement is the Kelvin scale, many manufacturers like to use terms like Day White, Natural White, Warm White and Cool White, but there is not a standard that defines a Kelvin temperature to associate with those terms. The general rule is WARM (2700K) to COOL (6500K+). The warmer the light, the more yellow tones, the cooler the light, there are more blue tones.
Here is the typical range of color temperatures on MYLED Lighting Guide:
    2700-3200 – WW – Warm White
    4000-4500 – NW – Natural White
    5000-5500 – DW – Day White
    6500-7500 – CW – Cool White

LED Bulbs are the perfect retrofit for your existing light fixtures. We have standard bases, candelabra, standard or Edison (E26), mogul (E39), MR16 and other typical bases that are common with incandesce.

Standard USA screw-in incandescent bulb has a base type of E26. E stands for Edison screw-in and the 26 means that the base is 26 millimeters. E27 is the European standard screw-in size. (Note: Eagle Light part numbers that contain ‘E27’ sold in North America will fit E26 sockets and in many cases support voltages from 85VAC to 220VAC)

LED light bulbs and LED lamps use the same socket designations as traditional light bulbs. Retrofit Solid State Lights (SSL) that use LEDs or OLEDs are normally designed to be compatible with existing sockets.   

Light Bulb Base and Socket Shape Types

B Bayonet Collar Base

E Edison Screw Light Base

F Single Pin Type Base

G Multiple Pin Type Light Bulb Base

K Cable Connections

P Pre-focused Light Base

R Recessed Contact(s) Base

S Shell-type Light Bulb Base

T Telephone Slide Base

W Wedge Base

X Special Type Light bulb Base

Lamp Number of Pin or Contacts

s Single Pin

d Double or Bi-Pin Base Type

t Triple Pin Base or Tri-Pin Base or 3 Pin Base

q Quadruple Pin Base or 4 Pin Base

B or Bayonet light bulb base and sockets

LED light bulb bayonet base types.

Examples of these base types include: BA75, BA95, BA150, BAY150, BA155, and BA220.

Bi-pin and G sockets and bases

LED light bulb bi-pin base types.

Examples of LED bi pin base types include: G4, G5, GU5.3, GU10, G13, T-1/2, T-3/4, T-1, T-1 1/4, T-1 3/4.

For more information  G type bases see G below.

E or Edison screw-in sockets and bases Screw-in bases, also known as Edison bases and light bulb sockets are used throughout the world. The naming conventions include terms like medium base and candelabra base. Often they are referred to with a letter-number designation that starts with an “E” followed by the number of millimeters in diameter of the base. If your base ends in a “d” this indicates a double contact base, this is typically used for 3-way bulbs. Typically North American 120VAC bases and 240VAC bases differ by only a millimeter and carry the same full name in each country. Many Eagle Light bulbs support both 120VAC and 240VAC, check specifications for the bulb to determine if the bulb supports 240VAC if your application requires that.

In most cases, our bulbs are B22/E27 the same size if not slightly smaller than the bulbs they replace. That is because LED technology packs a lot of light in a small package. And halogen installations. For fluorescent tubes, we have bi-pin, single pin and HO Ends. We carry PL based bulbs in G23, GX23, G24 and GX24 bases.

Both lights are energy efficient light sources that are much more efficient than the bulbs they replace. Here is a small list of the differences between CFLs and LEDs:
    a. CFLs are the spiral tube like bulbs. They are really mini fluorescent bulbs with self-contained ballasts. They contain a small amount of mercury. LED bulbs are the new style looking bulbs with heat sinks and round mini globes. They do not contain mercury.
        b. You can replace a 22W CFL bulb with 11W LED bulb.
        c. LED bulbs are instant on, instant off. CFLs take 30 seconds to 1 minute to warm up after they are turned on
        d. LED bulbs are not affected by turning them off and on. CFL bulbs are, as this will reduce their life.

 Yes. Many fixture are in our product range for outdoor application like garden, roads, stadium/ play grounds etc, all fittings are designed with water-proof fittings IP 65/67. Others need to be kept in a water-tight fixture. Read all instructions and manuals before using a LED bulb outdoors. 

Yes. They will fade as the bulbs gets near the end of its normal operating life. But it is a very gradual and hardly noticeable. This is called Lumen Degradation and is denoted on the website as L70. L70 is the amount of time the light takes to get to 70% of the initial lumen output.

Most of our bulbs come with either a 1 or 2 year manufacturer warranty. Warranties only apply for normal use of bulbs and do not include misuse or usage for which the bulb was  not intended to perform. All our warranties are parts-only warranty and same will be dealt with warrantee policy of company.

There is a lot that goes into answering this question. Design Lights Consortium has indicated in their specifications that you need at least 10,000 lumens to replace a 400W Metal Halide. Some other factors come into play, like surface reflectivity, obstructions and other source of light, such as natural light sources coming are product agnostic, we will select the best product that meets your needs. So we have the ability to replace 400W Metal Halide with 10,000 lumens up to 30,000 lumens. We do find that you needs more lumens indoor to do a proper replacement than you do outdoors.

We find that the typical range is as low as 17,000 lumens and as high as 23,000 lumens. Photo-metrics plays a major part in determining how much you need, spacing and reflectivity of the environment. As we  said above, we have found that you need more lumens indoors than you need outdoors to replace 400W Metal Halide.

There are several steps, but essentially this is no more difficult than a bulb and ballast replacement.
    1. Remove the fluorescent tubes, and then remove the ballast.
    2. Replace the existing tombstones (only if necessary). This step may be required with single ended powered tubes if you have shunted tombstones.
    3. Rewire the fixture to accommodate the LED tubes. Note: there are also ballast compatible tubes that allow you to convert to LED by simply removing the old fluorescent tube and replacing it with the LED tube. 

Our internal driver LED Tubes use AC current, and then converts the power to DC within the internal LED driver to light the LED’s. There are some tubes that can be driven from the fluorescent ballast, but we do not supply those tubes as we see fluorescent ballasts as a maintenance item. Ballasts consume about 4+ watts per fluorescent tube installed, so leaving the ballast in place reduces the energy savings as well.

We also can supply externally driven LED tubes. With these tubes, the driver is externally housed outside the tube, and is usually installed where the fluorescent ballast was located. External drivers act the same way as internal drivers; they accept AC power, convert it to DC which is supplied to the LEDs in the tube.

In the case where you have a native DC system (such as solar systems) you are best to look for externally driven LED tubes and forgo the installation of the driver. You will have to make sure the DC power that is supplied to the fixture is compatible with the DC power requirement of the tubes.

In single ended powered tubes, you power only one end. This type of installation is referred to as un-shunted. Since the tube has two pins on that end, you would send line to one pin and neutral to the other. (Think of line and neutral as the black and white wires of electrical wire)
In double ended powered tubes, you power both ends, one with line source, the other with neutral. This type of installation is referred to as shunted. In most cases, our tubes our single ended powered tubes. It conforms to the latest UL standards for safety. Proper installation of our tubes in existing UL fixtures maintains the UL certification of the existing fixture. We can also provide new fluorescent ends (tombstones) so that you can convert over to single ended powered tubes.

A ballast compatible tube is one where you can pull out the existing tube, leave the ballast installed, and install the LED tube.

No, but they work with most electronic ballasts.

L70 is the amount of time it takes for a light to degrade to 70% of initial lumen output.

Always buy based on lumens, watts is a number that is used to determine how much energy it takes to produce those lumens. It is important to pay attention to lumens per watt, or lm/w. The higher the number, the less energy you will need to produce the light. You will notice that some lights take less energy to produce the same amount of light, and this is something you should watch for. Typically, the higher the ratio, the better.

Almost always, it is the driver. That is why it is important to know who makes the driver in the LED fixture or retrofit you purchase. Brand names like Mean well and Philips are good. A LED product with a 1 or 2 year warranty is an indication of how good the driver is in that product. Typically a good driver should last more than 50,000 hours.

Heat. Heat is the enemy of electronics, the hotter it is, the shorter the light. However, with good design, you can create a light or fixture that can withstand some high heat environments. Typically a fixture or bulb with an external driver will last longer than an integrated fixture that has the LEDs and driver as one unit.

CRI is Color Rendering Index. It is a measurement of the quality of light. Whereas lumens is a measurement of the quantity of light, CRI is the measurement of quality. It is a scale between 0 and 100. 0 is bad, 100 is great. LED’s typically are in the 70-95 range. The higher the CRI, the more expensive the LED chip, and therefore the more expensive the product itself.

The governing body that certifies the quality and efficiency of LED Lights. They have implemented Energy Star rating of products  based on lumens per watt, more  lumens per watt means more saving in less usage of energy, Whereas Energy Star is for home owner type products, A BIS  Qualified product may be eligible for priority purchase or recommendation/acceptance  in some department. Your local utility designates whether you are eligible for rebates or not, and it varies between utility companies. Minimum 3 star and maximum 5 Star products are in demand in market.

That’s not a simple answer. For example, if your fixtures are relatively new and in good shape, retrofitting is a very good option. If your fixtures are old and deteriorating, then you might want to consider a new fixture. Both new and retrofit should last a long time. Both should perform well. Retrofitting is not prone to failure if you purchase the right LED retrofit kit to replace your existing bulbs.

The leftmost “1” in the horizontal axis indicates when the lamp was turned on after being off all night. The lamp turned itself off about 30 minutes later, shown by the leftmost zero. The lamp cooled to the point where it turned on again, about 14 minutes later. After another 6.7 minutes, the LED turned off, and so on. You can see that the on/off eventually settled down to between about 1.6 min. to 2.3 min. The entire elapsed time is about 2½ hours.

Now it was time to compare the operating temperature of the cycling lamp to a good one. Here’s where things get interesting.

“LED lights emit zero heat” is a slogan we hear over and over again.  While this is true (LED light emits no perceptible heat), the lamps themselves do emit some heat.  This can actually lead to problems with LED life because people place them in enclosed fixtures or airtight recessed cans.  While the bulb of an LED light won’t heat up like an incandescent (even after hours of light, the lighted surface of an LED is only slightly warmer than room temperature), the driver and heat sink, typically mounted in the neck and base, will heat up.  This heating is usually not hot enough to run a toy oven like an incandescent, but it can get hot enough to burn out the electronics in your light bulb.  Proper airflow prevents this from happening.  LED light bulbs will heat up if there is no airflow around the bulb, just like any electronic device.

We have an explanation regarding binning in another article.  But to summarize quickly:  An LED die (the chip in an LED array that emits light) is made in a batch and binned with other LEDs based on color and temperature.  Buying lights at different times can give you slightly different, but noticeable, color temperatures.  If you are replacing older incandescent, the color temperatures of incandescent bulbs change over time due to age.  This is why replacing an old 2700K incandescent with a new 2700K bulb (of any type) can seem like the new bulb is the wrong color.

LEDs do not naturally have issues with flickering or humming.  While LEDs turn on and off constantly to save on energy, the rate of change is faster than human eyes can see and flicker is unobservable.  Light flicker is usually caused by issues in the electric current, which can mean driver issues, dimmer incompatibility, or faulty wiring.  If your LEDs seem to be flickering, make sure you’re using a compatible dimmer and that there isn’t an issue with any of the drivers you’re using for the bulbs.

No product has ever been made that is produced with a 100% success rate.  While many companies and brands reduce the number of flawed products through testing and rigorous quality control, there will always be a flawed bulb or two that fails to light initially.  But what can lead

An LED lamp to fail prematurely when they are rated for 25-50,000 life hours?  Almost always, this is a problem with a damaged or failed driver, commonly due to overheating because of an enclosed fixture or housing.  Drivers are the main failure point for LED bulbs and are often the culprit for most LED problems as well. Internal Driver in an LED lamp having answered all of these questions,

The short answer is ‘both’, it’s all down to how you define lifetime of an LED and reliability.  One key difference between current lighting and LED’s is in the definition of a failure.  LED’s if driven correctly, are inherently reliable and do not stop working.  Their failure mode is decreasing light output, so it is the norm to specify the point in time when the light output drops to 50% of its initial output and even after this time, the LED is still working but it is not as bright.

LSPL has taken a leaf out of the lighting industry and raised the bar to 75% of initial light output, which matches the lighting industries requirements for lumen maintenance targets. So the claim for LSPL LEDs is 50,000 hours before the light output drops to 75%.  However the LED is only one piece of the solution, so we design all our drivers and color engines to match the lifetime of the LSPL LED at 50,000 hours or more.

:  For ease of wiring and flexibility, LED technology requires a constant current to power the LED and in the past, the control circuit to achieve this was very simple (resistor).  With the LSPL LED, an electronic power control driver ensures the LED’s are powered at the correct current under all circumstances. By using a constant current controller and wiring the LEDs in series, we can ensure that any manufacturing variations in the LED (Vf) and volt drops in the cabling is overcome. This allows the driver to be remotely located and allow long cable between the driver and LED boards (30m) without loss of performance.

One offshoot from this approach is the ability to mix different colors of LED’s together in a spring.

.  Your quest to compare current light sources against LED sources will be a tough one and you hear the phrase “it depends…” an awful lot!

Beware the claims of no heat, LED’s do generate heat BUT in a very small space, so the key to successful designs is the heat sinking of the LED, which is why LEDs are blended in with the fixture and not stand alone, like a capsule or glass lamp.

Second key point is LED’s require a driver and please make sure that the driver is the correct one for the LED you wish to use!  Also beware of electricians who think LED’s are low voltage halogens, and can save money by using cheap LV ballast.  (The LED works really bright for 0.5 milliseconds as one-shot flast bulb!!)

The cable can be 20 to 30 meters long however longer runs can be achieved using a higher grade cable.

The reason for this, is that we use constant current techniques to drive the LEDs which compensates for the voltage drop losses in the cable.

Capex and opex are the working methods in this segment, we  working only with capex model, participating in tender process with government departments,

Yes anybody can own the lighting on their own cost for systems and electricity charges,

LED’s Fail- Driver Related and Common Problem

Although for the most part LED lamps have proven themselves to be extremely resilient and long-lasting – both in terms of their light life and structure – that doesn’t mean that an LED lamp will never fail. If some

thing happened during the manufacturing process to make the lamp faulty or not as strong, you could end up with an LED lamp that goes out well before its time. And there are other factors that can lead to LED lighting failing. At ShineRetrofits.com, we want to make sure that you are fully educated about all aspects of our lighting products to ensure you can make the best decision about what lighting application is best for your project, and also to be prepared in case you run into an issue. Here is a look at some of the reasons why an LED lamp or an LED driver may fail.

For the most part, when an LED lamp is nearing the end of its life, it will not just automatically go out — generally the amount of light it emits will gradually lessen and it will not be as efficient as it once was. However, that’s not to say LED lamps never fully go out — it can happen, it’s just not very frequent.

One reason why an LED lamp might expire before its rated lifespan could have to do with the temperature of the environment it is in. If the temperature around it gets too hot and it does not have a proper heat sink, that can cause the LEDs in the lamp to overheat and then it will fail. That can happen, for instance, if you use an LED lamp that is not supposed to be used in an enclosed fixture, like a recessed can or downlight.

And although LEDs are generally rated to work at rather low temperatures, going lower than what is recommended can also have a bad impact on LEDs. It’s always important to read the specs or contact the manufacturer to make sure whether or not an LED lamp can be used in an enclosed fixture, and what the minimum and maximum operating temperatures are to make sure it’s the right fit for your project.

Another reason why an LED lamp might fail is due to something called efficiency droop. Basically every time the LED lamp is fired up and the electrical current that runs through the LEDs increases, the luminous efficacy of the LEDs drops up to 20%. So the higher amount of electricity you run your LED lamp on, the more of an impact it will have on the efficiency droop. To help combat this, an industry standard of operating at 350mA has been established. However, if your fixture needs to operate above that standard, you may find your LED lamp may not last as long.

Any issues within the structure of the LED lamp — either the LEDs themselves, how they are connected, or the lamp — can also be a reason why an LED lamp may fail. For example, if the LEDs themselves are not made of the highest caliber, you can already be setting yourself up to a problem. That is why in this case, many times you pay for what you get for — more expensive LED lamps will generally include higher grade LEDs that offer a better light quality and efficacy.

Generally speaking, the better materials that are used in your LED lamp, the less likely you will run into any issues with the process needed for the LEDs to illuminate. For example, structural issues with an LED could cause the electrical flow to run both ways through the LED, rather than just the one way needed for the p-n junction between the semiconductor materials.

As for the lamp itself, normally an epoxy is used in the construction of the LED lamp. Sometimes this epoxy can begin to turn a yellow color when heated, which can then actually absorb some of the light being produced, lowering the lamp’s efficiency. Additionally, the epoxy could also absorb moisture from the surrounding environment and transfer that to the LEDs, causing additional issues.

 Another reason why an LED lamp might have issues may have nothing to do with the lamp itself – it may be the LED driver is at fault. After all, an LED driver is an electronic device, and as we all know electronic devices are not flawless and do not last forever. As we mentioned in a previous article, the LED driver is what manages the amount of power that is flowed through an LED lamp or LED lighting system. They are necessary because LEDs run on DC power at a low voltage, so something needs to be used to convert AC to DC and protect them from power surges. So in this case, a bad LED driver could result in more power running through the LEDs, ultimately causing it to become overheated, which could hurt is lifespan or even just completely fry it. Or on the flip-side, if not enough power is getting to the LEDs, your light output and quality will suffer.

The other thing to keep in mind is that the LED driver may not be rated to last the same amount of time as the LED lamp. You would think manufacturers would try to make them last for a similar amount of time, but that’s not necessarily the case. And although many manufacturers are trying to make that happen, right now chances are very good you may end up with a 100,000-hour rated LED lamp running on an LED driver that is expected to last much less than that. So it’s important to note and ask the manufacturer for information on the lifespan of the LED driver so you have an idea on when that might need to be changed out down the line. Some reasons why an LED driver might fail include:

When the LED driver is doing its job, the power that it is keeping from running through an LED lighting system end up becoming heat. That heat build-up can eventually take its tole on the driver’s components, and over time can take a tole on the driver’s reliability and how well it functions.

Just like with the LED lamp itself, LED drivers are also rated to work the best within a certain environmental temperature. The more you go outside of that realm, the more it will not work as efficiently. In fact, a good rule of thumb is for every 10C you go over or under its maximum or minimum operating temperature; you’re reducing its efficiency by two. So it’s always important to make sure you know the proper operating temperature for the LED driver you choose, and keep it protected from the sun and other heat sources.

Additionally, not all LED drivers are damp listed. If you will be using the LED driver in an application that requires it to be exposed to the elements, make sure it can take any type of moisture or you may find yourself with a driver that no longer works.

If you select an LED driver that is not made from the highest possible parts, you may find yourself with some issues. Make sure to purchase your LED driver from a manufacturer that uses only quality parts, and does rigorous testing on the LED driver to make sure it an hold up to the increase temperature and other stresses it may encounter.

The defects occurring on LEDs can be related to different categories which are: the chip, as the central element and the internal and the external packaging. Due to the very different assembly technologies and types of constructions, as well as varying applications, an extended range of failure mechanisms can be observed.

Failure modes: Chip

During normal operation optical performance of LEDs gradually decreases during lifetime. In turn, this means a limitation in lifetime. Performance decrease is caused by growing defects in the epitaxy layers or on their boundaries, resulting in an increase of not radiating recombination and a decrease of optical efficiency. Usually a 30% or 50% decrease of optical performance is defined as defect while expected operation life is between 20,000 h and 100,000 h.

Ageing due to extension of defects is considerably dependent on junction temperature Tj and current. Therefore a sufficient control of these parameters is imperative for reaching expected lifetime.

Accelerated ageing, i.e. LED efficiency loss within a period lower than expected life, is caused by adverse factors like low quality of epitaxy layers as well as, often, an excess junction temperature due to insufficient heat dissipation. Furthermore, penetration of humidity or other contaminants, latent ESD (Electro Static Discharge) damage as well as an instable power supply can result in an accelerated degradation of epitaxy layers.

A catastrophic defect like a sudden failure can be caused by ESD or EOS (Electrical over Stress) due to electrical overload resulting in a serious damage of the epitaxy layer.

Failure modes:

LED internal construction

Interruptions in the current path respective the increase of electrical resistance have turned out to be frequent failure causes leading to reduced light emission, temporally instable function or even the entire failure. Delamination in the junctions between the chip and bond wire respective the chip and the substrate have also been detected. Since the interface area of the chip to substrate bond essentially influences heat dissipation, disruptions of the interface layer cause an increase of thermal resistance and chip temperature. Consequently, this leads to accelerated ageing of the LED.

In the LED production process are many failure sources to be considered. The soldering process has turned out to be especially critical because thermal overload can cause cracks, detachments or delamination’s along the border areas due to the various expansion rates of the materials. Extensive qualification tests and stable quality control at the LED manufacturer as well a very good control of the solder process during PC assembly are basics for a long lifetime.

Transparent encapsulation materials like silicone or epoxy are not hermetically sealing and therefore do not protect against humidity or other damaging materials. Furthermore, mechanical stress, for instance while bending the pins of 2-pin-LEDs, or thermal stress like the soldering process, can cause cracks or detachments of the LED joint compound and allow penetration of contaminants down to the chip or metal contact. Under adverse conditions this will result in modifications of the epitaxial layers or in corrosions in the interfaces. Another effect would be the already described consequences due to detachment of the electrical joints or the performance degradation due to damaged reflecting surfaces.

Other typical mechanisms that lower the useful lifetime are the ageing of encapsulation materials influenced by UV-radiation, or the degradation of the phosphor of white LEDs, which is also responsible for a color change of white LEDs (known as yellowing). This effect is more intense than the regular ageing of a chip.

Failure modes:

LED external assembly

By integration of LEDs in an external assembly, for instance in a PCB (Printed Circuit Board), more failure sources like malfunctions of electrical joints due to bad solder contacts must be considered.

Especially for high power LEDs, thermal contact and heat dissipation are very critical effects impacting degradation. The assembly should ensure and guarantee stable thermal contact during complete life.

Since humidity in LEDs, especially during the soldering process, may lead to the so called „Popcorn-Effect“, moisture-proof storage should be ensured.

In some applications the LEDs are covered by a protective lacquer or an external joint compound. Mechanical or thermal stress, as well as a reaction with outgassing materials can cause failures in the internal construction of an LED.

Methods for Analysis

LEDs present a broad range of failure modes which can be approached by using different methods of analysis. The objective of the failure analysis is to be able to allocate the observed failure pattern to a possible root cause and then show a way to avoid it. Because of the complexity, a failure analysis puts high requirements on technological know-how and the availability of methods for analysis.

Approach to find errors:
• Questions: In which environment was the LED/Module operated? For how long? Which driving mode was used?

• Measurements: Current/Voltage curves, intensity of light, wavelength/ color, radiation characteristics
• Non-destructive analysis: x-ray, light optical microscopy, scanning acoustic microscopy
• Destructive analysis: cross-sectioning, opening the package
• Physical analysis: FIB/REM, OBIRCH / Emission microscopy, EBIC, cathode luminescence

In order to limit the extent of the examinations, it makes sense to develop an efficient strategy that will cover the most comprehensive amount of historical information at the beginning of the failure analysis.

Visual light microscopy inspection

the visual inspection provides information about the external construction, the external integrity of the LED package and accessible parts of the internal construction.

Opto – Electric Measurements

Essential opto-electric parameters are the optical power, the spectrum (color), and the current-voltage characteristics.

The radiation characteristics in the far- and the near field discover the inhomogeneity’s of the light emitting area. Measurements of thermal resistance show problems in the thermal coupling.

Increased voltage in the forward direction points to a disturbance in the current path. Increased leakage current in reverse bias is a sign of a severe disorder in the epistaxis layers. This could be caused, for example, by ESD. The comparison of fine structures in the current/voltage curve between failed and working LEDs can help to differentiate between the various causes of errors.

Other non-destructive procedures
Because LEDs are usually packed in plastic housings, detachment of the bond wire of the LED chip can be detected by using a x-ray microscope. The scanning acoustic microscopy is also suitable for identifying delamination on the interface.

Destructive physical methods

To localize failures inside the LED, direct access to internal parts like the LED-chip or bond interfaces is required. Cross-sectioning or removing encapsulate materials by using chemical solvents are adequate treatment methods.

The inside structures are then accessible for high definition optical or SEM microscopy, and failures at the interfaces can be detected. Material analysis with EDX can determine impurities in the case of corrosion effects and give an indication to possible causes.

Failure analysis on chip level

To localize failures on chip level, methods are available that reveal defective areas on the chip, like dark spots or dark lines. Such methods are based on localized stimulation of light emission (cathode luminescence) or current flow by pointing an external electro beam (EBIC) or laser beam (OBIC) onto the chip. Emission microscopy uses very sensitive detection of light created by leakage current.

Special methods like TEM (Transmission Electron Microscopy) and sample preparation using FIB (Fused Ion Beam) are required for the deeper analysis of failures in the epitaxy system layer. Evaluation of the results require the possibility for comparisons to the known error patterns and good models because the defective structures within the semiconductor are very dependent on technology used. Therefore these methods are very expensive and only used in special cases.

:  It depends. There are two types of TLEDs, some like Philips Instat Fit LED T8 lamps require a ballast and some like Access Fixtures T8 LED Tube Lamps have an internal driver and work on 120v to 277v line voltage. Be sure what type of TLED you are using before installation.

This also depends on a number of factors. Manufacturers of both types make distinctly different claims. The InstaFit type TLED is an easier initial installation, but using an existing ballast means the ballast may fail long before the TLED fails. When the TLED stops functioning, it will be more difficult to determine the point of failure. Also, any TLED that requires a ballast is significantly more expensive as you have to purchase a new ballast or eventually replace the existing ballast to keep the lights on. TLEDs with an internal driver require removal of the old ballast and some rewiring before the TLED is operational. This adds some additional labor, but the resulting simplicity and savings are worth it. If somebody installs a T8 or T12 fluorescent lamp in a fixture that has been retrofitted for TLEDs with an internal driver, what will happen?

Absolutely nothing. The fluorescent lamp will not catch on fire or explode. It won’t illuminate either. A linear fluorescent bulb requires a ballast and power supplied on both ends. The power goes through the emitters causing a chemical reaction resulting in light. This process can’t take place in the absence of a ballast. Many TLEDs with integral drivers come with safety stickers for the luminaire stating: Only Use T8 LED Tube Lamps with Integrated Drivers.

Most typical industrial-grade power supplies are not suited for outdoor LED applications for several reasons. First, most traditional power supplies provide constant voltage output, while LEDs prefer to use constant current drivers. Second, most industrial power supplies are designed to operate up to 40°C ambient temperature without power de rating, which the LED drivers are often required to operate up to 60-70°C ambient without de rating for many indoor and outdoor applications. Also, most industrial power supplies do not have waterproof and lightning protection features which are required for most outdoor LED lamps.

The first issue is whether the

application requires constant voltage or constant current. If the supply is to drive the LEDs directly, it will typically require constant current. Next, the output voltage and/or current must be specified as well as the overall output power rating. Then the input voltage range must be determined. Many lighting applications require operation up to 277 V ac and so LSPL offers products with a 90-305 V ac operating range. Also important is the operating temperature range and the ingress protection (IP) rating. For outdoor lighting applications lightning protection is often a critical factor. Finally, compliance to efficiency, safety and electromagnetic compatibility standards should be evaluated.

Most solid state lamps consist of a significant number of high-brightness LEDs. These LEDs may be wired in any of a variety of configurations, each with their own advantages and limitations. Four of the most common configurations are discussed here.

Series

Perhaps the simplest configuration is to connect all of the LEDs in series, the anode of the second LED connected to the cathode of the first. A single, constant current source can then illuminate the entire string. This works very well with a limited number of LEDs in the string. However, as the string voltage is proportional to the number of LEDs in the string, long strings can generate rather high voltages. Assuming a forward voltage of 3.5V, a string of 24 LEDs would generate a voltage of about 84V. If any given LED fails short, there is limited impact on the operation of the lamp. However, if any LED fails open, the entire lamp will fail. Despite the high voltage, this is perhaps the most energy efficient way to power a lamp.

Parallel Strings

In order to minimize the operating voltage, multiple strings can be connected in parallel. Using the same

24 LEDs, one could form four series strings of six LEDs each and then connect these strings in parallel. The total voltage would now be only about 21V but it would require four times as much current to power the lamp. If any given LED failed open, one of the strings would fail but the other strings would remain lit. If any LED failed short, that string would carry much more current than the remaining strings. These situations will likely result in lower reliability as the remaining LEDs in the string with the failed LED are subject to significantly increased stress.

Matrix

In order to negate some of the disadvantages of the Parallel Strings configuration, it is possible to make additional connections in the configuration. In a Matrix configuration, multiple LEDs would be connected in parallel then multiple sets of these paralleled LEDs would be stacked in series. Using the above example of 24 LEDs, four LEDs could be connected in parallel and then stacked six high. The string voltage would still be 21V. The drive current would remain the same. The advantage is that one LED failing short (the most common failure mode) would take four LEDs out of service but the remaining 20 would operate normally without additional stress. The disadvantage is that load sharing between the paralleled LEDs is a function of how well the LEDs are matched in their operating characteristics.

Independent Strings

Perhaps the most robust method is to utilize a multi-channel constant current driver. Using the same example, in this configuration a four output driver would drive four strings of six series-connected LEDs independently. This would eliminate the problem of a single LED failing short. In this case, all other LEDs would be unaffected. The driver in this case would be somewhat more expensive having four independently regulated channels.

There are several benefits to use high-efficiency LED drivers. The first is very simply energy savings. The driving force behind the conversion to solid state lighting is energy efficiency. It only makes sense then to use high efficiency drivers as well. Energy savings in high efficiency drivers can be quite significant over the life of the driver. For example, the power dissipation of a 100W LED driver is 11.1W if the unit is 90% efficient, but increases to 25W if the unit is only 80% efficient. Assume the lifetime of the LED light is 40,000 hours, the difference of energy saving between these two units over the lifetime would be 556 Kilowatt hours. At 10 cents per kilowatt*hour rate, this translates into a cost saving of $55.6 over the lifetime. In some applications, the cost saving can be more significant if taken into account the losses in the utility line and the reduced energy consumption of the air conditioning system (if the lamp is used indoor). In addition, the lower temperatures associated with higher efficiency drivers can significantly improve product life and MTBF. The power dissipated in a 90% efficient driver is less than half that dissipated in an 80% efficient driver. Doubling the each 10 degree C increase in temperature. Therefore, higher efficiency driver heat in the lower efficiency driver significantly increases component temperatures. The life of the electrolytic capacitors in the driver decrease by about 50% with can easily have a 2-4 times longer projected life. Reliability is also a function of temperature and lowering temperature increases the reliability of all components in the driver.

There are two primary factors in the justification of most solid state lighting systems. The first is energy savings. However, there are other alternative lighting technologies that offer high efficiency for lower initial costs. The second justification, lower maintenance costs, is therefore critical. LEDs have the advantage of much longer life than most other lighting technologies. Reduced replacement and/or maintenance costs can be a very significant factor. However, if the power electronics in the system does not match the life/reliability of the LEDs then the justification of the system is in jeopardy. The life of an LED driver is mainly determined by the lifetime of the electrolytic capacitors employed. Therefore, to achieve long life of the LED drivers, it is critical to select long-life, quality electrolytic capacitors. Also, since the life of electrolytic capacitors drops by half for every 10°C increase in operating temperature, thermal management of these components is important. Two key factors for reducing the temperature of the capacitors are high efficiency design (dissipating less heat in the driver) and thermal design (effective conduction and/or convection of the heat into the ambient surroundings).

 This is determined by the life expectancy of components used in assembly of the unit. The weakest component with the shortest life expectancy determines the life of the whole product. For power supplies, electrolytic capacitors typically have the shortest lifetime expectancy. MTBF is applicable only during the normal operating life of the product. Mean Time between Failure (MTBF) represents the statistical approximation of the cumulative hours a number of units should operate before a failure can be expected. It does not represent the expected life of any given unit. For instance, if 10,000 units operated in the field for 1000 hours with 10 failures, the MTBF would be 1 million hours. This does not suggest that any unit will be expected to operate for 114 years. As another example, if product is determined to have an MTBF of 250,000 hours and 1000 units are deployed in the field, on average a failure could be expected about every 10 days if the products are operated around the clock or about once a month if they are operated 8 hours per day.

Conversely, the lifetime of a product indicates how long a product should be expected to survive under normal operating conditions. It is the period of time between starting to us

Power Factor (abbreviated PF) is the ratio of real power to apparent power in an AC power system and is expressed as a number between 0 and 1. Real power is the actual power drawn by the load whereas apparent power is the product of the load current and load voltage. Since the voltage and current may be out of phase this product may be significantly greater than the real power.

PFC is the abbreviation for Power Factor Correction. In order to maintain a high power factor, switch mode power supplies (including LED drivers) must employ some form of power factor correction.

This is an important issue because a load with a low power factor draws more current than a load with a high power factor for the same amount of real power transferred. Low power factor therefore results in greater power losses in the utility lines. There are a number of standards now in effect requiring certain levels of power factor correction in switch-mode power supplies and/or LED drivers.

The purpose of potting is twofold. First, it enhances the ingress protection (IP) rating of the unit by providing a waterproof barrier protecting the components from the intrusion of water under most circumstances. This is critical for outdoor applications such as streetlights.

Second, since the potting compound normally has much better thermal conductivity than the air, the potting is used to conduct heat generated by the key power components to the surface of the enclosure. This helps to greatly reduce the thermal stress on these components and thus increases the lifetime and reliability of the drivers substantially. It is estimated that the potting can typically reduce the operating temperatures of some of the key power devices by 20-40°C.

Ingress Protection (IP) ratings specify the environmental protection the enclosure provides. The IP rating normally has two numbers with the first specifying protection from solid objects or materials and the second specifying protection from liquids (water). The first number is specified from 0-6 with 6 implying complete protection from dust. The second is specified from 0-8 with the following implications:

Most LSPL drivers are rated IP67 which implies that the products are completely protected from dust and protected against temporary immersion in water.

IEC 61000-4-5 establishes a common reference for evaluating the immunity of electrical and electronic equipment when subjected to surges. The test method documented in this part of IEC 61000 describes a consistent method to assess the immunity of an equipment or system against a defined phenomenon.

Surge test standards for lightning protection as below, IEC61000-4-5 ranks:

NOTE X can be any level, above, below or in between the other levels. This level can be specified in the product standard.

LSPL offers the widest variety of high power LED lighting drivers available anywhere. As most LED lighting applications are justified on the basis of energy savings and reduced maintenance costs, LSPL accordingly focuses on providing high efficiency and long-life products. The LSPL portfolio offers products with up to 95% efficiency, power factor up to 0.99, robust lightning protection and IP67 waterproof levels. These products comply with global safety regulations and electromagnetic compatibility standards and feature over-voltage, over-current and over-temperature protection. They are widely used for LED street lamps, tunnel lights and architectural lighting.