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“With the rapid evolution of new high-performance mobile phones and other portable devices and the increasing number of new features, their lighting capabilities are becoming more complex,†said Adolfo Garcia, product line manager at AnalogicTech. “Many applications today include large, sophisticated primary display white light-emitting diodes (WLEDs), WLEDs for smaller secondary screen backlights, and flash LEDs for camera functions. AAT2846 and AAT2856 are identical The chip integrates six WLED outputs, two flashes and two LDOs, and each function can be individually controlled; this gives designers of portable systems a total display solution (TotalDisplaySolutions) to build a more compact and The opportunity for an economical portable system."
Excellent performance
The AAT2846 features a high current, triple mode charge pump capable of driving up to six backlight LEDs to deliver up to 30mA per LED. It can also drive two flash LEDs with a total current of up to 600mA. For applications that do not require flash, the AAT2856 provides a high current, triple mode charge pump capable of driving six backlight LEDs, delivering up to 30mA per LED.
Both the AAT2846 and AAT2856 feature AnalogicTech's AS2CwireTM serial digital control single-wire interface that individually turns the backlight and flash LED drive currents on and off. From 95μA to 30mA, the AAT2846 and AAT2856 backlight LED currents are set up to 32 levels; 20mA full-scale current and special microcurrent are also available to achieve optimum performance at low LED current levels. The six backlight outputs can be split into 5+1 format to support dual-screen mobile applications. In addition, the 6 LED outputs can be individually controlled by calling a special operating mode. Customizable, programmable settings for any main/sub-display, keyboard illumination, general status signals or flash signals are therefore possible. In order to achieve maximum brightness of the white LED, the backlight current matching ratio between channels is 1%.
The two flash output currents on the AAT2846 can be set to up to 16 levels with an external resistor, up to 300mA each (total current 600mA). In order to balance power consumption, the flash current matching ratio between channels is 4%.
Both devices integrate two high performance, low noise LDOs. Each LDO uses its own independent select input to support up to 200mA of output current. In order to meet the basic power requirements of various functions, such as a housekeeping controller or camera module, the output voltage of each LDO can be programmed to vary from 1.2V to 5V through a resistor divider. The two independently controllable LDOs of the AAT2846 and AAT2856 increase the flexibility of the system designer when sequencing multiple external power supplies.
Both the AAT2846 and AAT2856 have built-in short-circuit protection and overtemperature protection. The soft-start circuit automatically blocks excessive inrush currents during turn-on and mode switching.
Price and availability
The AAT2846 is specified over the -40 to +85°C temperature range and is available in a Pb-free, 28-pin TQFN44 package. The unit price is $1.42 per unit when order quantities are 10,000. The AAT2856 is priced at $1.14 each in quantities of 10,000.
AnalogicTech's two latest high performance charge pump products
AnalogicTech, Inc. (NalylogicTech, NASDAQ: AATI), a developer of power management semiconductor devices for mobile consumer electronics, today announced the availability of two new high-performance charge pump products that help designers Design a mobile phone with a much smaller size and more features. The two AAT2846 and AAT2856 devices are housed in a 4x4mm package with integrated backlight driver, high current flash driver and two general purpose low dropout linear regulators (LDOs). To avoid the use of multiple chips in space-constrained portable applications, the new devices maximize design flexibility by providing separate control functions for backlighting and flash current drive through a separate single-wire digital interface.