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Catalyst Semiconductor has announced chip in a family of patent-pending Quad-Mode adaptive fractional charge pumps. Capable of driving up to six white/color LEDs, the CAT3636 is designed with Catalyst’s innovative Quad-Mode switching architecture to give designers efficiency levels close to those of inductive boost converters and the simplicity of charge pumps, without adding cost, components or board space.



Catalyst Semiconductor’s Quad-Mode charge pump architecture delivers efficiency levels associated with inductor-based LED drivers, while eliminating the associated high-profile inductors and unwanted EMI. The Quad-Mode architecture of the CAT3636 adds a fourth mode of operation, 1.33x, without the need for the additional capacitor required by all existing four-mode charge pumps. The 1.33x fractional operating mode also reduces the input switching currents seen at the battery, minimizing the overall supply noise ?a critical parameter in portable devices such as cell phones.



The CAT3636 includes six LED current sinks configured into three separate banks, with each bank containing a pair of tightly regulated and matched output channels. Fully featured programmability and dimming control is achieved via Catalyst’s flexible 1-wire EZDim programming interface (Address and Data), which allows LED banks to be individually and accurately set. This further helps to reduce pin count and interface connections while still allowing flexible control of color LCD backlighting used in main and sub displays or combinations of RGB LED or flash functions in portable products.



http://www.catsemi.com/products/CAT3636.asp