An LED Driver Design for Visible Light Communication Transmitter
碩士 === 元智大學 === 電機工程學系 === 102 === This thesis proposed an LED driver design with active EMI mitigation for visible light communication transmitter. The system is based on a DC-DC boost converter. The proposed LED driver complies with the standard of Japan Electronics and Information Technology Indu...
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| Format: | Others |
| Language: | en_US |
| Online Access: | http://ndltd.ncl.edu.tw/handle/63412117414971850544 |
| Summary: | 碩士 === 元智大學 === 電機工程學系 === 102 === This thesis proposed an LED driver design with active EMI mitigation for visible light communication transmitter. The system is based on a DC-DC boost converter. The proposed LED driver complies with the standard of Japan Electronics and Information Technology Industries Association (JEITA CP-1222). It employs the OOK modulation for data transmission.
The spread spectrum techniques are employed to mitigate electromagnetic interference. Different from most of the solutions which used on-board DSP or MCU, we design an on-chip 10th-order LFSR to generate pseudo-random vectors. The last four LSBs are used to modulate the clock's frequency; in consequence, the clock spectrum is spread and the corresponding power spectral density as well as the EMI are reduced. The data transmission is accomplished by a two-level load current control such that corresponding to different load currents the LED illumination varies to represent data ‘1’ and ‘0’ respectively.
The system is implemented in the TSMC 0.35μm CMOS process with the die size of 1.45#westeur024#1.49 mm2. The measurement results showed that the proposed mitigation scheme can reduce the EMI by 18 dB while providing the peak-to-peak driven currents between 60 and 120 mA. The carrier frequency can be as fast as 2.5 MHz and the data rate is up to 500 kbps. The settling times for the load current transition from 1 to 0 s and vice versa are less than 2.3 ns.
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