The Sipex SP6686 charge pump delivers up to 400mA to camera flashes, in a variety of operating modes tailored to current needs and flash modes. Capable of 94% efficiency maximum, the regulated boost/buck pump provides two independently adjustable and selectable output current levels, suitable for both “flash” and “torch” modes. Operating at 2.4MHz switching frequency, which leads to small, low-value support components, the IC needs just three tiny external capacitors and ni inductors. It switches from linear buck mode to two-times boost mode seamlessly, based on the voltage if the supply battery; the current does not depend on the LED forward voltage as some competitive units do. The 10-lead device operates from 2.7 to 5.5V, and includes various protection modes and 1 microamp shutdown current, and is $1.59 each in 1000-unit quantities.
