LED Lighting Blog

LED lighting from the 1964 invention has been developed to the popularization of the era, and its energy-saving, environmental protection, high brightness, low power consumption, long life, impact resistance and other advantages, the outlook is extremely broad; interior lighting in its infancy, as well as its inherent drawbacks, mainly in the following aspects:
1, the problems caused by inconsistency:
Theoretically LED light-emitting diodes are able to, and in fact all the LED’s electrical properties are different, each manufacturer’s production process is inconsistent, or even a big difference, that is, the same manufacturer are all different times of the process differences; different semiconductor manufacturers use the purity of raw materials there is a difference, which makes the LED luminous intensity is not identical with the drive current, over-current capability and heat resistance differences will naturally different; packaging technology and packaging different materials, making the overall cooling capacity is not the same, there is a combination of thermal expansion and cooling Pang problems. It is not difficult to see, LED light-emitting diode in the short term there are still great differences between individuals, if each lamp only one LED, good control. Such as TV, DVD on the power indicator; And when we make use LED lighting, it is not a single of the LED, but with more than hundreds of thousands of LED into an array access circuit, due to differences between the LED there is always one of the first damage, broken when there are several (usually short), the current will increase the damage other of the LED. This is inconsistent with the results, but also one of the factors restricting its development.
　　2, the drive circuit complex issues:
a. voltage matching terms in, LED, unlike ordinary incandescent bulbs, can be connected directly to 220V AC mains. The LED is 2 – 3. Volt low-voltage drive, the design must be of complex circuits, different uses of the LED lamp, to be equipped with different power supplies. b. during current supply, LED’s normal operating current 18mA-20mA, power supply current of less than 15mA when the LED luminous intensity is not enough, and more than 20mA occurs when the light fades and the resulting LED aging, while fever greatly increased, accelerated aging, life expectancy shortening, when more than 50mA will quickly damage, in order to extend the service life of LED lights, commonly used IC power supply, electronic transformers, power supply and other discrete components, high current drive, be equipped with high-power tube or silicon device, and the other plus protection circuit to a constant current, constant voltage power supply circuit and the power circuit complexity, failure rate, component costs, production costs, service costs will rise. This greatly limits the competitiveness of the market and buying groups.
　　Second, LED lighting circuit characteristics:
A, multi-LED lamp series and parallel matrix structure; B, not control the brightness; C, LED current changes in a certain range does not significantly affect the illumination; D, LED damage cause is that current is too large, more than 50mA, representing small voltage changes caused by a large current changes. So you can control the over-current, which provide the basis for the simplified circuit.
　Third, the solution to the problem:
If WHPTC overcurrent device for protection from the principle known, when the circuit when the current exceeds a predetermined value newsletter speed automatic protection, automatic reset after troubleshooting, without manual replacement. On the LED, the voltage change is not the direct cause of damage to the LED, the LED current increases is the real killer. Using this feature, the LED circuit protection has the absolute advantage, so simple power supply into reality. Practice has proved that the LED circuit failure before the effective protection. The following figure shows, because there can be omitted WHPTC constant current circuit. Device costs, production costs, service costs are greatly reduced. Also greatly increased the product’s market competitiveness.