Diagram to DC/DC power supply different power LED general lighting application requirements and circuit scheme

For dc - Dc ( DC / DC) Power supply of LED lighting applications, can be discussed according to different power range.

　　1） 1 ~ 3 w LED step-down DC/DC applications typically 1 to 3 w step-down DC/DC LED lighting applications including MR11, MR16, automotive lighting, solar power, etc. The input voltage of this kind of application for 5 to 28 Vdc, support 350 ma and 700 ma constant current output, frequency of 500 KHZ to 2 MHZ, no less than 90% of energy efficiency, working temperature range for - 40 ℃ to 125 ℃. In this type of application, can use various semiconductor CAT4201 step-down LED drive. This proprietary device switch control architecture, which can drive 7 series LED ( 24 v input) , energy efficiency is as high as 94%, and provide the LED open-circuit protection, overheating protection and current limiting protection features.

figure 1: CAT4201 1 ~ 3 w DC/DC LED solutions.

　　2） 1 ~ 30 w LED step-down DC/DC applications

1 ~ 30 w typical step-down DC/DC LED applications include MR16 lamp, street lighting in the secondary side of DC/DC LED driver. Such applications, the input voltage range is 7 to 120 Vdc, the output voltage range of 6 to 110 Vdc, 350 ma, ma, 700 or 1 a constant current output, energy efficiency is not lower than 90%. Such applications can use various semiconductor NCL30100 step-down LED drive, the external switch MOSFET device, provide flexible input voltage and output current is designed, the energy efficiency higher than 95%, its application circuit diagram in figure 2.

figure 2:1 - based on NCL30010 30 w leds and 3 - based on NCP3066 step-down applications 20 w leds booster application.

  　　3） 1 ~ 20 w LED boost DC/DC applications typical 3 ~ 20 w DC/DC LED application in DC/DC booster LED drive. The input voltage of this kind of application for 5 to 28 VDC, support 350 ma and 700 ma constant current output, no less than 90% of energy efficiency. Such applications can use various semiconductor NCP3065 / NCP3066 LED drive. NCP3065 / NCP3066 can configured to buck, boost, single ended primary inductor converter ( SEPIC) Different patterns and inverter, etc. , and provide the corresponding car application version, namely NCV3065 / NCV3066. Figure 2 shows the NCP3066 booster configuration LED application circuit diagram.

　　4） 1 ~ 3 w LED flashlight step-up/step-down 1 ~ 3 w LED flashlight application in both booster type, also have a step-down type. Booster type applied input voltage in the range of 1 to 2. 5 Vdc, the working frequency of 1. 2 mhz; Step-down type application input voltage in the range of 4 to 5. 5 Vdc, the frequency of 1. 7 mhz。 Two types of applications are required to support 350 ma and 600 ma constant current output, energy efficiency is higher than 90%. In the 1 - 3 W LED flashlight booster applications can use various semiconductor NCP1421 step-up DC/DC converter, the same power range of flashlight step-down LED application can use various semiconductor NCP1529 low voltage step-down converter, application circuit diagram as shown in figure 3, respectively.

figure 3: based on the step-up and step-down based on NCP1529 NCP1421 1 ~ 3 w LED flashlight application.