Analyze LED brightness stability and energy saving
Since 2010, developed countries such as Europe, the United States, and Japan have successively begun the implementation of the ban on incandescent light bulbs, which is based on light sources that limit low luminous efficiency. Incandescent light bulbs are disabled and replaced by light-saving bulbs, cold-cathode tubes, LEDs, and the like. However, considering the limit of harmful substances of incandescent light bulbs in the future, LED light sources will be the best choice.
Working principle and characteristics on LED light source
The light emitting diode is a diode synthesized from a semiconductor material and is composed of a PN interface. When a forward voltage is applied, electrons and holes combine to emit energy in the form of photons, and thus have light emitting characteristics. The light source is generated within millimeters of the PN interface. The wavelength of the emitted light varies depending on the characteristics of the material. There are red, yellow, green, and blue light emitting diodes. The brightness of light emitting diodes can be adjusted by the operating voltage (current). In a large range of operating current, the brightness of the light-emitting diode increases with the increase of the current.
Stability of LED illumination
The brightness of light-emitting diodes varies with the size of the current, and the light-emitting diodes manufactured therefrom have slightly different voltage and current curves. Therefore, the brightness of the LED lighting often cannot be stabilized due to the fluctuation of the power supply voltage. In order to maintain the brightness and stability, a constant current LED driver is required. The constant current driver enables the light emitting diode to operate in a fixed current mode and thus has high brightness of stability. Constant current drivers also allow LEDs to operate at a constant current for a long period of time.
Energy saving of LED lighting
The advantages of LED lighting are energy saving and safety, but due to constant current work considerations, energy consumption also increases relatively, so the lighting system design aims at low energy consumption. As mentioned earlier, the voltage drop of the constant current driver is within 2V, which is a design considering low power consumption. In order to maintain the constant current operating state of the light emitting diode, the feedback circuit controls the converter switching period based on the output current.
In the LED lighting products currently flooded with the market, their power input systems are of two types: a front-end AC power input system plus a back-end constant current control module. Such products include refrigerated cabinet light strips, indoor fixtures, and street lamps, table lamp, MR16, AR111 and so on. The other type is AC power supply direct input system integrated AC/DC converter and constant current circuit. Such products include bulb type LED lamps such as E27 and GU10, PAR lamps, T5 and T8 LED lamps.