Do you Know LED Driver?

LED Driver Features

According to the characteristics of grid electricity rules and LED driver power supply requirements, the selection and design of the LED drive power should be tooken into account the followings: First, high reliability: especially like the drive power of LED street lamp, it is mounted at a height place and inconvenient for repairs and maintenance. Second, high efficiency: Since LED is energy-saving products, so ac led driver efficiency should be higher. For the structure of power installed in the fixture, is particularly important. LED luminous efficiency decreases with the rise of the temperature of the LED, the LED heat is very important. Power, high efficiency, small power depletion, heat small fixture lamps will reduce the temperature rise. It is beneficial to delay the LED light failure. Third, high power factor: The power factor is the grid load requirements. Generally, it is less than 70 watts of electrical appliances, and there is no mandatory target.

LED Driver Principle
The curve of the forward voltage drop (VF) and the forward current (IF), we can know from the curves, when the forward voltage exceeds a threshold value (about 2V), i.e. commonly referred to as the conduction voltage can approximate that, IF is proportional with VF. LED's optical properties are usually described as a function of current, and rather than a function of voltage, flux (φV) and IF curve, therefore, constant current driver can better control the brightness. In addition, LED's forward voltage drop range is relatively large (up to 1V above), VF-IF curve of the figure as above shows, small changes of VF will lead to a larger, IF changes, which led to the brightness of the more big change. So, using a constant voltage source drive cannot guarantee the consistency of the LED brightness, and the impact of reliability, lifetime and lumen maintenance of the LED. Therefore, ultra-bright LED usually uses co
LED Driver Requirements

LED driving circuit, in addition to meet safety requirements, the additional basic functions should be two aspects: First, as far as possible to maintain the constant current characteristic, especially when the power supply voltage is ± 15% of the changes, and should be able to maintain the output current at ± 10 constant current drive change.% range with LED as a display or lighting equipment or backlight when you need them, and the main reason is: avoid the drive current to exceed the maximum rating, to affect its reliability. Second, to obtain the expected brightness requirements, and to ensure that the individual LED brightness, and color consistency. The second driver circuit should be kept lower power consumption, so as to make the LED system efficiency maintain at a high level.

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