AnalogicTech dual charge pump enables low power backlighting

AnalogicTech has introduced a multi-function, high efficiency, dual charge pump that is very efficient in low-current mode, delivering extremely low quiescent current and allowing designers to continually backlight displays while consuming minimal amounts of power.

Many portable devices using different display types, and (particularly) transmissive displays require some minimal level of backlighting at all times. AnalogicTech's AAT2805 supports both white LED backlight and camera flash applications for portable systems that run on lithium-ion/polymer batteries.

Featuring a light load mode with quiescent current as low as 80—A (typical), the AAT2805 minimizes power consumption during backlight operation. The backlight charge pump drives up to four LEDs at a total output of 120mA. Current sinks may be operated individually or in parallel to drive higher current LEDs. To maximise power efficiency, the charge pump operates in 1x, 1.5x and 2x modes.

The device automatically selects the most efficient mode by comparing the forward voltage of each LED with the input voltage. The AAT2805 is available in a 16-pin, thermally-enhanced, lead-free TDFN44 package and is qualified across the -40°C to 85°C temperature range.

- Henri Arnold
Electronics Express Europe
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