Abstract
As a solid light source, LED has an enormous application prospect because of its advantages, such as high efficiency, long life, stability and so on. Due to the disadvantages of the current Power Supply which has high power consumption and large volume, a PWM power supply based on LM2575 DC/DC step-down chip has been designed with the characteristics of small volume, high efficiency, steady performance, low cost. It is used to drive powerful (1W) white LED by constant current which can be adjusted by regulating external potentiometer, and the light intensity is also changeable. According to the test data, we can learn that the efficiency of the power supply can reach to 85%, and when the input voltage is changed from 11V to 38V, the LED’s drive current and luminous intensity keep constant to achieve the purpose of constant current drive. When the total resistance is changed from 0.6Ω to 3Ω by adjusting the external potentiometer, the LED’s drive current varied from 350mA to 70mA and the luminous intensity is changeable. Because the designed parameters of this power supply meet the requirements of electric motor car, the device can be applied to the electric motor car which still use lamp bulb to light. Using LED instead of lamp bulb to light, the power efficiency of electric motor car will be improved.
Keywords: Powerful LED; Constant current driver; Adjustable intensity; DC/DC converter
