| Summary: | 碩士 === 國立高雄應用科技大學 === 電子工程系 === 100 === In recent years, there is a significant growth in various LED lighting applications. The stable forward operating current of LEDs is helpful to enhancing service life of LEDs. Therefore, supplying LEDs with stable current is becoming an important topic of LED driving circuit. This paper proposes an integrated continuous-conduction mode (CCM) voltage-control buck converter used in the LED driver. A systematic design flow, including system level, circuit level and transistor level is presented. The MATLAB, SIMPLIS and HSPICE design tools are used for the simulations of different level designs. A high-voltage level shifted (HVLS) circuit is designed to control the power MOS of the driving circuit.
The buck converter is fabricated in the TSMC 0.25μm 60V Bipolar-CMOS-DMOS (BCD) technology and the chip area is 0.9 × 0.80473 mm2. Simulation results show that the buck converter has output voltage within 14.65V to 14.7V and the output current of about 0.35A with 500 kHz switching frequency and the input voltage of 30V to 50V. The output voltage ripple is 50mV and the power efficiency is 86% at 0.35A load current. The maximum power efficiency is 90% at 0.7A load current.
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