A REVIWE ARTICLE OF VARIOUS TECHNIQUE OF LED DERIVER IC DESIGN

The Light-Emitting Diode (LED) driver is an important part of Visible Light Communication (VLC) systems. The main challenge of the VLC LED driver is to offer a high data transmission rate with high power efficiency. This paper presents the design of a white light LED driver that combines the LED lighting with VLC technology. The proposed LED driver uses linear current regulation and controls the AC current signal and the DC current through a single power device for the purposes of high speed, high efficiency and high integration. It also can support the modulation format of orthogonal frequency division multiplexing (OFDM). In addition, this work presents an impedance reduction technique to enhance the bandwidth of the LED driver. And a first-order preequalizer is utilized to enhance the electron-optical-electron (E/O/E) bandwidth in the VLC system due to the bandwidth limitation of the phosphor converted LED. The VLC LED driver is fabricated in a standard 0.5_m CMOS technology with chip area 1540_m×1250_m. It is available in a standard SOP-16 pin package. The experimental results show that the optical modulation bandwidth of 10.9 MHz has been achieved with the forward biased LED current of 350 mA. By using the OFDM data modulation scheme, the data rate of 50 Mb/s is demonstrated.