The putting forward of the problem
In general, at least in the 1W above call high-power LED power。The 1W, 3W, 5W, 8W and 10W is common on currently，Which is known as the “green light”, is moved to new development direction that a large current (300mA ~ 1.4A), high efficiency (60 ~ 120lm / W), adjustable brightness。However, the LED current is determined the luminous intensity of high power LED。LED current is too strong will cause the LED lighting is too weak, the current is too weak will affect LED luminous intensity,and therefore need to provide constant current LED driver power to ensure power safety LED use, but also need to meet the expectations brightness requirements, and ensure that each the LED brightness, color consistency. So, traditionally used to drive the bulb (tungsten wire), power fluorescent lamps, energy saving lamps, sodium lamps and other light sources are not suitable for direct drive high power LED. LED Driven by mains power supply also need to address the buck, isolation, PFC (power factor correction) and constant current problem, need a higher conversion efficiency. Currently, there are thousands of models dedicated high-power LED constant current driver chip on the market, Most adopt a dedicated hysteretic converters of chip, low voltage input range, boost, buck can, PWM control, power switch can be internal or external, the output current can reach 1.5A, the built-in overvoltage, undervoltage, open / short and temperature protection circuit.