| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 104 === Along with the rising awareness of environmental protection, people more notice about the importance of energy saving. According to the International Energy Agency (IEA) noted, the electricity consumption of global lighting equipment accounts for almost 20% of global electricity output. Hence, how to save energy from lighting equipment has become a big issue to the public. Traditional lighting is low life, low luminous efficiency and environmental unfriendly, and it doesn’t meet the needs of energy saving policy. In recent years, the technique of Light Emitting Diode (LED) matures, and the advantage of LED contains long life, small volume, and high luminous efficiency, gradually replacing traditional lighting. Because the luminance of LED depends on the forward current, it’s important to supply a stable current to LED.
The research, based on the DC-DC boost convertor, designs an IC driver to control the output voltage and makes the current of LED stable. The IC driver consists of auto and manual control. In the mode of auto control, LED is operated at 20mA. In the mode of manual control, LED is operated according to the input control voltage. The functions of the IC include low temperature drift circuit which outputs a reference voltage which temperature coefficient is less than 118ppm/℃ between 0~75 ℃. By the auto control circuit, the overall structure can be started up to steady state faster. The system only takes 4ms on driving the highest load.
The supply voltage of the LED IC driver is 3.3V, and the power consumption is 6.03mW. The input voltage of boost structure is 3V, which can be generated by two AA batteries, and the output voltage is up to 11.754V. The overall efficiency is 91%. The specification of the LED loads is operated at 20mA and only drives one series. The proposed design is realized using TSMC 0.35 μm CMOS technology.
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