LED power determines the quality of LED lamps

In recent years, the reason why LED lamps are buoyant, the market's annual rate of 130% increase, the most important reason is due to environmental protection (no energy-saving lamps like tribute, toxic substances), long life (LED theoretical life is in 100,000 hours Left and right), high photoelectric efficiency (energy saving) and other advantages, in the process of large-scale use of the market, some manufacturers of LED lighting designers are immature or illegal profit-makers of LED driving power to use unqualified source data in order to maximize the benefits. By cutting corners, the service life of LED lamp products made by defective power supplies is greatly shortened. The practical life of most products on the market is still lacking 1000 hours, and the light failure is more than 50% in a few days. The following will be an important statement on why LED power supplies determine the quality of LED lamps. Elements?

LED drive power is the key to LED lighting, it is like a person's heart, to produce high-quality, LED lighting for lighting must give up the constant voltage mode to drive the LED.

Many high-power LED packaging plants now pack many individual LEDs in parallel and in series to consume a single 20W, 30W or 50W or 100W or even higher power LED, even though these individual LEDs are pre-packaged. All of them are strictly selected and paired. However, due to the small number of internal components, there are dozens or hundreds of single-chip LEDs. Therefore, the packaged high-power LED waste products still have great differences in voltage and current, and Compared to a single LED (usually a single white, green, blue working voltage in the 2.7-4V, a single red, yellow, orange light operating voltage in 1.7-2.5V) parameters greater difference! (Prompt that the LED lighting factory just launched can not ignore the packaging quality of LED light source)

Due to the particularity of LED processing and manufacturing, the current and voltage characteristics of LEDs consumed by different consumer manufacturers and even the same consumer product in the same batch of products all have large individual differences. Now take the typical example of a high-power 1W white LED as an example, according to the LED current, voltage change rules to do a brief description, the ordinary 1W white light application forward voltage is about 3.0-3.6V, that is, when the nominal 1W LED In the 350mA current flow, the voltage across it may be 3.1V, may also be 3.2V or 3.5V may also be other values, in order to ensure the lifetime of 1WLED, ordinary LED consumer manufacturers to recommend the use of 350mA current lamp factory Drive (some manufacturers think about the life expectancy from the perspective of packaging process and heat dissipation, will recommend the user to reduce to 320 mA or 300 mA), when the forward current through the LED reaches 350 mA, LED two A small increase in the forward voltage of the terminal will cause the LED forward current to rise substantially, causing the LED temperature to rise linearly, thereby accelerating the LED light decay, shortening the lifetime of the LED, and severely burning the LED. Due to the LED voltage The specificity of the current change, and therefore made a stringent request to drive the LED power supply. Some manufacturers, in order to reduce the cost of the product, the use of constant voltage drive LED (some low-power high-power LED lamps used in the factory, is the use of constant voltage power supply in series with one or several high-power resistors to work), also brought batches Each LED emits a large difference in brightness when it is consumed, LED does not work in an optimal state, and has a short life span and ferocious heat.

If you purchase a LED lamp, when the voltage is normal (such as AC220V when the mains electricity) compared to light, and when the voltage is relatively low (such as when the city fell to AC190V) that the brightness drops a lot, then you can be sure that your purchase of LED lighting quality It is not good that the quality of the LED driver power supply used in the luminaire is inferior.

Constant current source driving is the best LED driving method. It adopts constant current source driver and does not need to connect the current limiting resistor in series in the output circuit. The current flowing on the LED is also not affected by external power supply voltage change, ambient temperature change, and discreteness of LED parameters. Impact, so that we can maintain a constant current, give full play to the excellent features of LED.

The LED constant current power supply is used to power the LED lamps. Since the current flowing through the LEDs is automatically detected and controlled during the power supply operation, there is no need to worry about excessive current flowing through the LEDs when the power is applied. Bad power supply.

The constant current drive method can prevent the change of the forward voltage of the LED and cause the current to change. At the same time, the constant current makes the brightness of the LED stable, and it is also convenient for the LED lamp factory to ensure the disparity of the products when mass consumption. Therefore, many manufacturers have used Fully aware of the importance of the drive power, many LED lamp manufacturers have abandoned the constant voltage mode, and choose a slightly higher constant current mode to drive LED lamps.

Some manufacturers are concerned that the use of electrolytic capacitors in the power driver board will affect the life of the power supply. This is actually a misunderstanding. For example, if a 105-degree, 8,000-hour high-temperature electrolytic capacitor is used, depending on the prevailing electrolytic capacitor life-budget budget method, "every degree of reduction is 10 degrees. , life expectancy is doubled, then it works for 16000 hours under 95 degree environment, working life is 32000 hours under 85 degree environment, working life is 64000 hours under 75 degree environment, if practice working temperature is lower, Then life will be longer! From this point of view, simply using high-quality electrolytic capacitors has no effect on the life of the drive power supply!

In addition LED lamps should pay attention to: As the LED will emit a lot of heat during the work process, so that the junction temperature of the die rises rapidly, the higher the LED power, the greater the heating effect. LED chip temperature will lead to changes in the performance of light-emitting devices and the attenuation of electro-optic conversion efficiency, serious or even failure, according to experimental tests indicate: LED itself temperature rises by 5 degrees Celsius, luminous flux will drop 3%, so LED lamps must pay attention to LED The heat dissipation of the light source itself shall, as far as possible, increase the heat dissipation area of ​​the LED light source itself, and reduce the operating temperature of the LED itself as much as possible. If the conditions permit, it is better to locally separate the power source from the light source and pursue a small volume blindly. The ignoring of the operating temperature of the lamps and power supply is not desirable. From the appearance, the appearance is compact, but the life span is short and the light failure is increased. It is a typical “small loss”.

After the above we explained the relationship between the LED power supply and the LED lamps through technical explanations. In the process of designing the manufacturers, the power supply was strictly designed in accordance with the standards, and the driving mode was selected rationally to design higher quality lamps.