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STMicroelectronics Introduces New White LED Driver with Specific Features for Small LCD Module Backlight | | |
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 Geneva,
November 5, 2004 - STMicroelectronics (NYSE: STM) has introduced a
special part to drive the white
LEDs that are becoming popular for color LCD backlighting or portable
devices.Color LCDs demand a pure white backlight so their colors are properly displayed. White LEDs are becoming the preferred technology for this but need a typical forward voltage of between 3V DC and 4V DC. The latest lithium-ion batteries have minimum operating voltages down to 2.8V DC. Since the brightness of an LED is proportional to its forward current, dedicated current-source power supplies are needed to drive white LEDs from the batteries used in portable applications. The STLD20D is an inductive boost converter designed to drive a white LED with high efficiency over a wide range of battery voltages. It can drive up to four LEDs in series from a 2.8V DC battery voltage and offers dynamic supply voltage rejection to prevent backlight flickering. Conversion efficiency is more than 80%. The part includes an LED disconnect switch to reduce current leakage in stand by mode, soft start functions and a shut-down mode with dimming control. The STLD20D offers a low standby current of less than 1ľA, and includes over-voltage and over-temperature protection. The part has a pulse-width modulation input, so that a white LED can be dimmed without reducing its biasing voltage, which could affect the color of its output. This allows a pure white color to be kept over the entire dimming range. Peak inductor current is adjustable on versions of the STLD20D packaged in an SOT-23. The part is also available in a 3 x 3mm QFN. Pricing is US$0.45 in quantities of 100K pieces. Further information is available at www.st.com/asd About STMicroelectronics STMicroelectronics is a global leader in developing and delivering semiconductor solutions across the spectrum of microelectronics applications. An unrivalled combination of silicon and system expertise, manufacturing strength, Intellectual Property (IP) portfolio and strategic partners positions the Company at the forefront of System-on-Chip (SoC) technology and its products play a key role in enabling today's convergence markets. The Company's shares are traded on the New York Stock Exchange, on Euronext Paris and on the Milan Stock Exchange. In 2003, the Company's net revenues were $7.24 billion and net earnings were $253 million. Further information on ST can be found at www.st.com. |
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