LED lighting power supply circuit design technology application.

The arrangement of LED and the specification of LED light source determine the basic drive requirements. The main function of the LED driver is to limit the current flowing through the LED under certain working conditions, regardless of the input and output voltage. The most common use is to use transformers for electrical isolation. This paper discusses the factors of LED lighting design.
1. General requirements for LED drives.
The driving LED faces many challenges, such as the forward voltage varies with the temperature and current, while the LED forward voltage of different individuals, different batches and different suppliers will also be different. In addition, the "color point" of the LED will drift with the change of current and temperature.
In addition, multiple leds are often used in the application, which involves the arrangement of multiple leds. Various kinds of arrangement, the preferred drive series single series of LED, because this way no matter how change forward voltage, output voltage (Vout) how to "drift", provide excellent current matching performance.
Of course, the user can also be used in parallel, series and parallel combination and cross connection (as shown in figure 1) and other arrangement, need for "mutual matching" LED the application of the forward voltage, and other advantages. In a cross connection, if one of the leds fails to open, the drive current of only one LED in the circuit doubles, thus minimizing the effect on the entire circuit.