Design Of The Specific Circuit For Transmitter Of Visible Light Communication

Visible Light Communication(VLC)technology,based on existing LED devices,combines wireless optical communications with illumination to provide a new communications solution for the future smart society.Compared with the traditional RF communication technology,visible light communication has no damage to the human body and sufficient resources without license permission as well as higher information security.It is considered as a good complement to 5 G communication and WIFI technology.However,the research on transmitter with high power,high efficiency and high speed,and the specific integrated circuit of LED driver is rarely reported.This thesis designs two kinds of white LED based VLC transmitter.One of them is designed to drive OSRAM 1W LED,and using UMC 0.18?m standard CMOS technique.The other is designed to drive CREE 10 W LED,and a high power,high efficiency and high speed visible light communication transmitter by using discrete components is designedIn the design of specific circuit of VLC transmitter,the first-level pre-emphasis circuit is designed and analuzed at first,and then its theory is extended to the design of multi-level pre-emphasis circuit.The multi-level pre-emphasis technology is used to effectively compensate the low frequency response of the LED.A DC coupling and AC coupling multi-level pre-emphasis integrated circuits are successfully taped out,the single module bandwidth of 500 MHz and the system bandwidth of 125 MHz are achieved.In a design of the high power,high efficiency,high speed VLC transmitter,the traditional LED drive circuit is analyzed and compared,and a novel push-pull drive structure is proposed with new power devices GaN FET.The speed performance of optical transmitter is improved by combining the adjustable carrier sweep-out technology and freewheeling technology.Finally,through actual test,the highest rate of 10 Mbps and the efficiency of 93.17% were achieved when 10 W LED was used as the light source of the optical transmitter.The VLC system was also achieved,which contributes to the integrated and practical exploration of VLC technology.