Camera power supply

Maxim has introduced the MAX1584/MAX1585, high efficiency, small complete power supplies for slim digital still cameras and digital video cameras.

The devices provide higher efficiency and a smaller size when compared with other conventional multichannel controllers that use only external power switches.

The step-up and step-down DC-DC converters internal to the devices include synchronous rectifiers that provide 95% efficient conversion for the 5 V system and 1.5 or 1.8 V core supplies.

On both devices, the AUX3 is a step-down controller that generates a 3.3 V logic supply. In addition, two controllers supply power for the white-LED backlight module, positive and negative CCD biases and positive and negative LCD biases.

On the 1585, the AUX2 is an inverting DC-DC controller that generates negative outputs without a transformer.

The devices' 5 x 5 mm, TQFN package is claimed to be 70% smaller than existing solutions using only DC-DC controllers and eliminates at least 27 external components such as transformers, diodes, external power switches, resistors and capacitors.

All DC-DC channels operate at one fixed frequency settable from 100 kHz to 1 MHz. The input-voltage range is 0.7 to 5.5 V and they are intended for single-cell lithium-ion (Li+) and two or three cell alkaline battery inputs.