What does a "self-ballasted" LED mean ?

With the rapid development of semiconductor lighting technology, various types of lamps and luminaires using LEDs as light sources have emerged in large numbers, especially many LED lamps that serve as alternatives to traditional light sources. For example, LED bulb lights have replaced ordinary incandescent bulbs and self-ballasted fluorescent lamps, LED-R lights and LED-PAR lights have replaced reflector incandescent bulbs, and LED-MR16 has replaced MR16 halogen lamps. Because they can conveniently replace light sources without the need to replace traditional fixtures, they have been quickly embraced by a large number of consumers.

1.What is a self-ballasted LED lamp?

A self-ballasted LED lamp refers to an LED lamp that integrates the stable ignition components with the lamp base. In reality, the stable ignition components of LEDs do not belong to the ballast components. However, due to the use of the term "self-ballasted" in the draft of IEC 62560 "Self-ballasted LED lamps for general lighting services > 50V – Safety specifications," which describes the LED's driver similarly to a self-ballasted fluorescent lamp, it is translated as "self-ballasted LED lamp" in Chinese national standards. In the U.S. ENERGY STAR standard, it is referred to as an "Integral LED Lamp," meaning an integrated LED lamp.

2.Main Performance Parameters of Self-Ballasted LED Lamps (Integral LED Lamps)

2.1 Lamp Power

The lamp power referred to here is the total input power of the entire lamp, not just the power consumed by the LED light-emitting components. Some companies mistakenly consider the power of the LED devices as the lamp's power. For example, if a lamp uses three 1W LED light sources, they might rate it as a 3W lamp. Such an error can result in measured power exceeding the standard requirements. In reality, lamp power should also include the power consumed by the driver control circuit.

2.2 Power Factor

Power factor is the ratio of active power to apparent power. A low power factor indicates a high reactive power, which can increase power consumption in the supply line.

2.3 Luminous Flux

Luminous flux refers to the radiant energy that the human eye can perceive. It is the most important indicator of illumination light sources.

2.4 Luminous Efficacy

Luminous efficacy (luminous efficiency) is the amount of luminous flux produced per unit power, calculated by dividing luminous flux by actual power consumption. It reflects the efficiency of converting electrical energy into light energy, with higher luminous efficacy indicating greater energy efficiency.

2.5 Color Characteristics

Color characteristics are determined by color rendering and color temperature. The actual color emitted by the lamp is called the color rendering, determined by the color coordinates of the CIE 1931 (x, y) chromaticity diagram. The spectral characteristics of the light emitted by the lamp affecting the surfaces of objects being illuminated are referred to as color rendering. In practical applications, color rendering is represented by the general color rendering index Ra.

2.6 Luminous Maintenance Rate

Luminous maintenance rate refers to the ratio, expressed as a percentage, of the luminous flux of a lamp at a specific time during its lifespan under specified conditions to its initial luminous flux.

2.7 Switching Test

Switching tests involve repeatedly turning the lamp on and off to assess its ability to withstand switching shocks. LED lamps have a clear advantage in terms of switching performance compared to traditional light sources.

2.8 Lifetime

Lifetime is divided into the lifespan of a single lamp and the average lifespan.

The lifespan of a single lamp refers to the cumulative time from ignition to failure or when the lamp works until its luminous maintenance rate falls below a specified value.

The average lifespan refers to the cumulative time until the luminous maintenance rate of the lamp reaches the required level, and it can continue to burn until 50% of the lamps reach the lifespan of a single lamp.

Even though a lamp may still be operational, when its luminous maintenance rate is very low, it can be considered to have lost effective lighting functionality. Therefore, when the luminous maintenance rate falls below a specified value, it is considered to be a failure. This specified value can be 70% or 50%, depending on the standards.

It's important to note that the lifespan claimed in product specifications refers to the average lifespan, not the lifespan of each individual lamp.

3.Comparison of Differences in International Standards for Self-Ballasted LED Lamps (Integral LED Lamps) Performance Requirements

The standards for the performance requirements of self-ballasted LED lamps (integral LED lamps) include the U.S. ENERGY STAR Program Requirements for Integral LED Lamps ENERGY STAR Eligibility Criteria (December 2009) and the International Electrotechnical Commission's IEC/PAS 62612 Self-Ballasted LED Lamps for General Lighting Services Performance Requirements (draft) (hereafter referred to as ENERGY STAR standard and IEC draft, respectively). These three standards have specific differences in their requirements, which are detailed in this text to help individuals understand and use these standards correctly.

3.1 Lamp Power

Considering that the rated power of smaller lamps may have a small 15% numerical value, which is difficult to control, the allowable power deviation is relaxed to 0.5W. For example, for a lamp with a rated power of 2W, 15% of the rated power is 0.3W, which is less than 0.5W, so the maximum allowable power deviation is 0.5W. If 15% of the rated power exceeds 0.5W, then that value is taken.

The requirement in the industry standard is that "the difference between the actual power consumption and the rated power should not exceed 15% or 0.5W." This means that whether the actual power consumption is greater or less than the rated power, the power deviation should meet the requirements.

Clause 7 of the IEC draft requires that "the power loss of LED lamps shall not exceed 15% of the rated power," which limits the range of actual power consumption above the rated power, setting an upper limit value. It does not impose any restrictions on power deviations below the rated power.

While the ENERGY STAR standard does not specify requirements for lamp power, it mentions compliance with UL 1993 - 1999, which sets limits for positive power deviations: not exceeding 10% + 0.5W of the rated power.

3.2 Power Factor

The industry standard requires that "when the lamp operates at rated voltage and frequency, its actual power factor shall not be lower than the manufacturer's specified value by 0.05." The standard does not specify the exact value of the power factor but requires manufacturers to self-declare it. However, it does set a lower limit for the actual power factor, e.g., if the nominal power factor is 0.95, the measured value should not be less than 0.90.

The ENERGY STAR standard in clause 4 requires that lamps with a power less than or equal to 5W have no specific power factor requirements, while lamps with a power greater than 5W should have an average power factor greater than or equal to 0.7. Since improving the power factor can impact costs and efficiency, and low-power lamps have a smaller impact on the power grid, this requirement is reasonable.

The IEC draft does not have specific requirements for power factor.

3.3 Luminous Flux

The industry standard in clause 5.5 states that "the initial luminous flux of the lamp can be claimed by the manufacturer or seller, but the measured value should not be lower than 90% of the rated value." In other words, it is not mandatory to claim, but if claimed, the measured value should not deviate more than 10% below the claim. Deviations above the claim are allowed. There are no specific requirements for the luminous flux value.

The ENERGY STAR standard requires a minimum luminous flux of 200 lm for non-standard lamps and specifies minimum luminous flux values based on the original target lamp's luminous flux for replacement lamps. Non-standard lamps are LED lamps that do not specify replacing existing standard incandescent lamps. Replacement lamps are LED lamps that specify replacing a particular standard incandescent lamp. For example, an LED lamp claiming to replace a 60W incandescent lamp must have a luminous flux of at least 800 lm.

Clause 8 of the IEC draft requires that "the luminous flux measured at 0 hours should not be less than 90% of the nominal luminous flux," meaning that the actual initial (0-hour) luminous flux should not deviate more than 10% below the nominal luminous flux. Deviations above the nominal value are allowed, but there are no specific requirements for the luminous flux value. The standard does require the luminous flux value to be indicated on the lamp and its packaging.

3.4 Luminous Efficacy

Industry standard clause 5.5 states: "The initial luminous efficacy level of a lamp can be claimed by the manufacturer or seller, but its measured value should not be lower than the specified value. If the manufacturer or seller does not make a claim, it should be assessed as level III."

Luminous efficacy is defined with minimum values specified based on four power segments, two color ranges, and three levels. Luminous efficacy is divided into three levels: I, II, and III, with III being the lowest. Manufacturers can claim one of these three levels, and if no claim is made, it is assessed as level III. For example, a 5W self-ballasted LED lamp in daylight color claiming to achieve level I efficiency should have a measured luminous efficacy value of no less than 60 lm/W; if not claimed, it should meet level III standards, which requires a minimum of 40 lm/W.

ENERGY STAR standards require that non-standard lamps with a power rating of less than 10W have a luminous efficacy of no less than 50 lm/W, and those with a rating of 10W or more should have a luminous efficacy of no less than 55 lm/W. Replacement lamps are divided into three types: omnidirectional, decorative, and directional lamps. For omnidirectional lamps, the luminous efficacy should be no less than 50 lm/W for lamps less than 10W and no less than 55 lm/W for lamps 10W or greater. Decorative lamps should have a luminous efficacy of no less than 40 lm/W, and for directional lamps, with a diameter less than or equal to 20/8 inches, the luminous efficacy should be no less than 40 lm/W, while lamps with a diameter greater than 20/8 inches should have a luminous efficacy of no less than 45 lm/W.

The IEC draft does not specify luminous efficacy requirements.

3.5 Color Characteristics

3.5.1 Color Temperature, Color Coordinates, and Color Tolerance

The industry standard provides target values for six typical color tones, their color coordinate values, and related color temperatures, with a color tolerance (SDCM) of ≤7 using MacAdam ellipses. Currently, LED lamp color control can be challenging, so the standard has relaxed the requirements accordingly.

ENERGY STAR standards specify only four color temperatures, omitting the 5,000K and 6,500K high-color temperatures found in our national standard, and require color temperatures to fall within a specified quadrilateral area. Color coordinate tolerance is measured using the deviation value Duv from the CIE 1976 (U', V') chromaticity diagram, with a requirement that Duv be less than 0.006. Color Maintenance is also required, meaning that the color shift (Duv) should be within 0.007 when tested at 6,000 hours.

The IEC draft, in clause 9.1, recommends six color temperatures and requires testing at 0 hours and at 25% of the rated lifetime (up to 6,000 hours). The measured color temperature values from both tests should fall within the specified color tolerance range.

Color tolerance (SDCM) in MacAdam ellipses is divided into six levels: Cat3 to Cat8, with Cat3 having a color tolerance of ≤3; Cat4 ≤4, and so on, up to Cat7 with a tolerance of ≤7. Cat8 means the tolerance exceeds 7 and is not assessed, and the specific level must be declared by the manufacturer or seller on the product and packaging. Color temperature is assessed not only at the initial stage but also during the rated lifetime, with an additional test point at 25% of the rated lifetime. This is necessary because white LED light sources for illumination typically use blue LED chips covered with yellow phosphor, and both may degrade differently, causing color drift. Therefore, assessing color change during the lifetime is essential.

3.5.2 Color Rendering Index (CRI)

Industry standard clause 5.6 stipulates that "the initial value of the general color rendering index Ra for a lamp should not be lower than the specified value by 3 units." The specified value is 80, meaning that the measured value should not be lower than 77 to meet the standard, without specifying positive deviation.

ENERGY STAR standards in clause 4 require a minimum Ra value of 80 for all lamps, both non-standard and replacement lamps. The assessment method is that the average Ra value should not be lower than 80, and the lowest single value should not be lower than 77. It also requires a special color rendering index R9 for saturated red to be greater than 0.

The IEC draft does not specify the required value for the color rendering index. However, it mandates that the CRI must be indicated on the lamp and packaging.

The industry standard requires that "the color rendering index Ra of LED lamps should be tested at 0 hours and at 25% of the rated lifetime (up to 6,000 hours), and the deviation of the actual measured CRI value should not exceed 5 units from the nominal value." This assessment covers both the initial value and the value at 25% of the rated lifetime, with no allowance for deviations in either direction.

3.6 Lumen Maintenance

The industry standard specifies that "the lumen maintenance of a lamp at 3,000 hours should not be less than 92%, at 6,000 hours, it should not be less than 88%, and at 70% of the rated life, it should not be less than 70%."

ENERGY STAR standards require non-standard lamps, omnidirectional lamps, and directional lamps to have lumen maintenance greater than or equal to 70% at the rated life of 25,000 hours. To shorten the verification time, an additional assessment point is added at 6,000 hours with an average lumen maintenance of greater than or equal to 91.8%. For lamps with a power rating of 10W or greater, lumen maintenance testing is required at the rated life in a high-temperature environment of 45°C. For decorative lamps, lumen maintenance at 15,000 hours must be greater than or equal to 70%, and the assessment includes average lumen maintenance at 6,000 hours (greater than or equal to 86.7%). In clause 8, "Lumen Maintenance Testing and Lifetime Claim," it is also stipulated that if a longer lifetime is claimed (e.g., non-standard lamps, omnidirectional lamps, and directional lamps with a claimed lifetime greater than 25,000 hours, or decorative lamps with a claimed lifetime greater than 15,000 hours), the lumen maintenance requirements must be increased.

The IEC draft in clause 10.1 provides five levels of lumen maintenance, where the light decay, defined as 1 minus lumen maintenance, is compared between 6,000 hours and 0 hours. CatA represents light decay not exceeding 10%, CatB not exceeding 20%, and so on, up to CatE with a light decay not exceeding 50%. This standard does not mandate specific levels but requires manufacturers to declare and label them.

3.7 Switching Test

The industry standard specifies: "Under rated input voltage, the lamp should be switched on and off for 30 seconds each, repeating this cycle 15,000 times. After the test is completed, the lamp should operate normally for 15 minutes."

ENERGY STAR standards stipulate a cycle of 2 minutes on and 2 minutes off, with the number of cycles reaching half of the rated hours. For example, if the claimed lifetime is 30,000 hours, the number of switch cycles should not be less than 15,000.

The IEC draft in clause 10.2.1(b) specifies: "Under rated input voltage, the lamp should be switched on and off for 30 seconds each, with switching cycles up to half of the rated life (e.g., if the rated life is 20,000 hours, then switch 10,000 times). After testing, the LED lamp should still operate and remain illuminated for 15 minutes."

3.8 Lifetime

In the definition of lifetime, besides lamp failure, a lumen maintenance below the specified value is also considered as the end of life. The industry standard defines "failure" as lumen maintenance below 50%.

The IEC draft uses lumen maintenance below 50% as the criterion for end of life but allows specialized lighting applications to choose 70% lumen maintenance as the end-of-life criterion. The choice of lumen maintenance can be determined by the manufacturer, but if 50% is used, it must be labeled on the product and packaging, while 70% can be mentioned in the product manual. ENERGY STAR standards use L70 lifetime, which means the end of life is reached when lumen maintenance reaches 70%.

The industry standard specifies: "The average lifetime of the lamp should not be less than 25,000 hours."

ENERGY STAR standards stipulate a minimum lifetime of 15,000 hours for decorative LED lamps and 25,000 hours for other LED lamps. Manufacturers are allowed to claim higher lifetime ratings. Decorative lamps can claim 20,000 hours, and all types of lamps can claim 30,000, 35,000, 40,000, 45,000, or 50,000 hours. However, when claiming higher lifetimes, the lumen maintenance requirement at 6,000 hours is also raised, and for lamps claiming a lifetime greater than 25,000 hours, additional lumen maintenance testing at other time points is required. For example, if claiming a lifetime of 35,000 hours, the lumen maintenance at 6,000 hours must reach 94.1%, which is 2.3% higher than the 91.8% required for a claimed lifetime of 25,000 hours. Additionally, lumen maintenance at 8,750 hours must be tested, with a requirement of at least 91.5%.

The IEC draft specifies that lamp lifetime is determined by the manufacturer and should be indicated on the lamp. Lifetime is assessed based on both lumen maintenance and the lifetime of the built-in electronic ballast. Since self-ballasted LED lamps are a single unit and cannot be disassembled without permanent damage, the testing is performed with the complete lamp.

Testing for the lifetime of the built-in electronic ballast includes switching tests, temperature cycle shock tests, and high-temperature lifetime tests. The temperature cycle shock test involves placing the LED lamp without power in a -10°C environment for 1 hour, followed immediately by placement in a 50°C oven for 1 hour, repeating this cycle five times. The high-temperature lifetime test requires the LED lamp to operate at the rated voltage and a temperature of 45°C until 25% of the rated lifetime is reached (up to 6,000 hours). After testing and when the temperature has returned to room temperature, the lamp should remain illuminated for 15 minutes.

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