What are the differences between LED power supply and LED drive power supply

What is the difference between LED drive power and LED power? In fact, there is no difference in essence, but the name is different. There are many kinds of names for LED power supply. In fact, ballasts, LED power supply and LED driver power supply are all power supplies applicable to LED lamps. Now let's give you a detailed answer.

During the design of LED lighting fixtures, it is necessary to consider the selection of appropriate LED drive power supply. The quality of LED drive power directly determines the quality of LED lighting fixtures, and the connection mode of LED should be considered. At present, the connection modes of LED include series, parallel, hybrid and cross array. The LED light panel design is to carry out reasonable matching design (connect the LEDs together in a reasonable way) according to the actual situation of the product design, so as to ensure the normal operation of the LED light panel. The forward voltage range of white LED lamp beads is generally 3.0~3.6 V, the power is 1W, 3W, and the working current is 350mA, 700mA (the actual working current is 300mA, 600mA). However, for LED fluorescent lamps, LED downlights and other lighting fixtures, multiple small and medium power LED beads are combined in series and parallel, and the working current of each LED is 45~120 mA. It usually requires a large number of LED beads to match to produce uniform brightness. At present, there are also COB surface light sources with 12 strings, and the current varies from 3W to 60W.

Note:

① The arrangement of LED and the specification of LED light source determine the basic driver requirements. The main function of LED driver power is to limit the current flowing through LED under certain working conditions, regardless of how the input and output voltages change.

② The VF value of the LED lamp bead is related to the luminous color and the operating temperature of the LED. The VF value of the LED varies with the temperature. The higher the ambient temperature is, the smaller the VF value is. The VF value is inversely proportional to the ambient temperature.

③ The VF value of the LED lamp bead is different from that of the manufacturer, and the VF value of the same packaged LED is also different from that of different manufacturers.

To design LED driver circuit (power supply), it is necessary to master the working principle of LED lamp beads. The brightness of LED beads is mainly related to VF and IF. A small change in VF will cause a large change in IF, resulting in a large change in brightness. To keep the LED in the best brightness state, a constant current source is required to drive it. LED driver circuit is a power conversion circuit, but it outputs a constant current rather than a constant voltage. In any case, a constant and average current should be output, and the ripple current should be controlled within a certain range.