高効率、白色LED用電流マッチングを提供する1x/1.5xの安定化チャージポンプ
SUNNYVALE, CA-September 3, 2002-Maxim Integrated Products
(NASDAQ: MXIM) introduces the MAX1570, the first integrated solution combining the highest efficiency 1x/1.5x charge pump with low-dropout current regulators in a compact 4mm x 4mm thin QFN package. The MAX1570 features 37% longer battery life versus a typical 2x charge pump. The 150mA current limit supports up to five white LEDs with uniform LED-to-LED current matching of 0.3% to ensure uniform backlighting of color LCD displays. No external inductor or ballast resistors are required. It is the most efficient charge pump to generate white LED supplies for cell phones, smart phones, PDAs, and digital still cameras.
With constant 1MHz PWM switching frequency, the MAX1570 only requires two 1µF ceramic flying capacitors and one 4.7µF ceramic output capacitor for a complete solution.
The input voltage range is 2.7V to 5.5V. The MAX1570 also has a low 200mV dropout voltage to maximize battery life. It features digital or PWM brightness control, low input ripple, soft-start to limit inrush current, and complete input-to-output disconnect during shutdown (0.1µA shutdown current).
The MAX1570 is available in a space-saving 4mm x 4mm 16-pin thin QFN package screened for the extended-industrial temperature range (-40°C to +85°C). Prices start at $1.90 (1000-up, FOB USA). An evaluation kit is available to speed designs.
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