WHITE LED CHARGE PUMP IN 3mm x 3mm TDFN ACHIEVES 83% EFFICIENCY
SUNNYVALE, CA-February 25, 2004-Maxim Integrated Products
(NASDAQ: MXIM) introduces the MAX1574 high-efficiency LED charge pump that requires only one transfer capacitor for simplest implementation. Packaged in a 3mm x 3mm TDFN, this device is the simplest and smallest solution for cell phones and other handheld devices. The charge pump drives up to three parallel white LEDs with a regulated, constant current for uniform intensity. By utilizing adaptive 1x/2x modes and low-dropout current regulators, it achieves up to 92% peak efficiency or 83% average efficiency over the full 1-cell Lithium-ion (Li+) battery input-voltage range. It provides 0.6% current matching for uniform backlighting of color LCD displays. The MAX1574's high output current (up to 180mA) permits use in camera strobes/flashes, movie lights, and keyboard backlight applications.
The MAX1574 features a single-wire, serial-pulse interface for dimming down to 5% of peak, soft-start to limit inrush current, overvoltage protection, thermal shutdown, and complete input-to-output disconnect during shutdown (0.1µA shutdown current). The input voltage range is 2.7V to 5.5V. The 1MHz fixed-frequency switching allows for tiny external components and the regulation scheme is optimized to ensure low EMI and low input ripple.
The MAX1574 is screened for the extended-industrial temperature range (-40°C to +85°C). Prices start at $1.35 (1000-up, FOB USA). An evaluation kit is available to speed designs. For additional white LED solutions, visit: http://www.maxim-ic.com/whiteLED.
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