Application To Wireless Control LED Drive Circuit Design

With the development of semiconductor technology, LED gradually becomes a new type of electric-light source due to its superpower and high luminous efficiency. In LED lighting device, driver IC has been the indispensable module in order to make LED to work. At present, there are many shortcomings in driver chips such as single function, difficult to connect to the wireless receiving decoder etc. Therefore, only design a multi-function, high performance driver chip can meet the needs of the market.Based on the principle of Buck switching power supply and wireless control technology, thesis presents a suitable for the wireless control LED driver IC using CD035 MVA BCD technology library. The chip that solved the wireless interface problem, will promote the use of LED drivers and wireless control module. According to the wireless receiving decoder type, a non locking type wireless receiving decoder interface circuit is designed. In addition, in order to expand the use of the driver chip, diver IC increases the brightness adjustment function. The performance of LED lights, switching power supply circuit and types are introduced, and the comparison circuit, source of band-gap reference circuit, oscillator circuit, 3-8 decoder circuit, digital potentiometer circuit and protection circuit are designed in this paper. The spectre simulation and layout structure of the driver has been carried out.The voltage compared with feedback terminal can choose the internal band-gap reference voltage, the external input voltage and the digital potentiometer output voltage. Through the comparator control the working status of the power switch tube to stabilize the output current, realization the aim of stable LED brightness. Driver IC realizes the continuous adjustment of brightness by using wireless pulse signal that control the output of digital potentiometer. The oscillator is used to adjust the frequency of the power tube in order to reduce the ripple current.Drive circuit using cadence software to design, the circuit principle, simulation curve and layout structure show that: ① using the external input voltage or internal reference as feedback comparative terminal, the output current reaches the corresponding level and has small ripple current. ② the driver circuit realize brightness adjustment using the digital potentiometer as feedback comparative terminal that the wireless signal control LED. ③ the wireless interface circuit adopted master-slave flip-flop achieve the wireless latch and maintain the stability of the circuit. ④ there are about 1.2m W power consumption, about 83% efficiency, the input voltage fluctuation ranging from 6V to 12 V, about 1817 1330 area of the layout for the driver IC. Therefore, the drive circuit is not only achieved high performance of the driver function, but also provides a convenient interface designer for LED circuit and wireless control. The driver chip will promote the widespread use of LED and technology.