LED power supply there are many classification methods:
Divided into constant voltage output characteristics of series, the constant current series;
Different input characteristics are divided into general series, and high power factor series;
For different purposes, divided into the waterproof series, series and is not waterproof;
Isolation circuit structure is divided into different series, and the isolation series;
Control mode is divided into different adjustable light series, and dimming series.
LED environmental protection, long life, high photoelectric conversion efficiency of the many advantages of theory, the service life of LEDs over 100,000 hours, but in the actual application process, due to the inappropriate choice of the design of drive power and drive mode, or with LED lights do not match the LED are easily damaged or light failure is very serious. reduces the reliability of the LED lamps.
LED manufacturers and LED specifications, current, voltage characteristics are different now to the typical specifications of the white LED, for example, in accordance with the LED current, voltage variation, the general application of the forward voltage of about 3.0-3.6V, typical voltage of 3.3V, current is 20mA, the ends of LED forward voltage exceeds 3.6V, the forward voltage of a small increase in the LED forward current are likely to become doubled up, the LED light emitting body temperature has ascended faster, thus speeding up the LED light attenuation, and shorten the life span of the LED, serious and even burn out the LED to the LED voltage, current changes in characteristics, strict requirements on the design of the drive power.
Many manufacturers of LED light products (such as guardrail, light cup, projection lamps), with resistance, the step-down, and then coupled with a Zener diode voltage regulator, power supply to the LED, so to drive the LED there is a big defects, the first is low efficiency, consume large amounts of electricity on the dropping resistor, and may even be more than the electricity consumed by the LED, and can not provide high current drive, because the current increases, the greater the electricity consumed in the dropping resistor. so many products of the LED can not parallel, are used in series to reduce the current stable voltage capability poor, can not be guaranteed by the LED current does not exceed their normal work requirements, the design of products will be adopted to reduce the LED voltage across supply-driven, this is to reduce the LED brightness at the expense of using resistance, step-down mode to drive LEDs, LED brightness can not be stable when the power supply voltage is low, the LED brightness dimmed, high voltage power supply The brightness of LED street lights. resistance, the biggest advantage of the step-down manner to drive the LED is low cost.
According to the LED current, the voltage changes the characteristics of constant voltage LED drive is feasible, although the commonly used voltage regulator circuit, there is the disadvantage of poor regulation accuracy is not enough and steady flow, but in the application of certain products may be too precise design its advantage is still the other drive mode can not be replaced.
Constant current drive, is an ideal LED driver, it can avoid the LED forward voltage changes caused by the current changes, constant current LED brightness and stability, so many manufacturers choose the constant current mode to drive LEDs.
However, due to a variety of different LED power performance and conversion efficiency vary, so choose a suitable, efficient LED special power supply, can be truly revealing the high performance characteristics of the LED light source because of the low efficiency of LED power you need to consume large amounts of electricity to the LED-powered, so highlights the characteristics of the LED energy-saving LED power LED work stability, energy efficiency, longevity, have an important role.