Monolithic, multi function LED driver simplified lighting circuit device integrated with backlight, flash and LDO

Sunnyvale, California, August 7, 2007 -- specifically for mobile consumer electronic devices to provide power management semiconductor devices developers analogictech Technology Co. Ltd. (AnalogicTech, NASDAQ: AATI), announced the launch of two days prior to the latest high performance charge pump products, they can help the designer to design a volume significantly reduced, function more mobile phone. The two AAT2846 and AAT2856 devices are integrated in the 4x4 mm package with a backlight driver, a high current flash drive and a total of two common low dropout linear regulators (LDOs). In order to avoid using multi chip in portable applications from space constraints, these two new devices provide a separate control function of backlight and flash current driven by digital interface independent, to achieve maximum design flexibility.

Along with the rapid evolution of the current high-performance mobile phones and other portable devices, new features, the lighting function is increasingly complex, AnalogicTech product line manager Adolfo Garcia said. "White led many application including the main display of large precision (WLED), deputy for smaller screen backlight WLED, as well as for the camera flash light emitting diode (Flash LED). AAT2846 and AAT2856 integrated 6 WLED output, two flash and two LDO on the same chip, and each function can be independently controlled; it is portable system designers to provide comprehensive solutions rely on display (Total Display Solutions), to build a portable system more compact and the economy the opportunity. "

Superior performance

The AAT2846 features a high current, three mode charge pump capable of driving up to 6 backlight LED, capable of providing up to 30 mA of current for each. Can also drive two flash LED, the total current up to 600mA. For applications that do not require flash applications, the AAT2856 provides a high current, three mode charge pump that is capable of driving up to 6 LED backlight, providing up to 30 mA of current for each LED.

Both AAT2846 and AAT2856 have AnalogicTech AS2Cwire serial digital control single wire interface, which can be turned on, off, or set the drive current of backlight and flash LED. From 95 A to 30 mA, the AAT2846 and AAT2856 backlight LED currents are set up to up to level 32; the mA can also provide a full range of 20 LED current and a special micro current to achieve optimum performance at low current levels. 6 backlight output can be divided into 5+1 format, to support dual mobile phone application. In addition, the 6 LED outputs can be individually controlled by calling a special mode of operation. Therefore, it can be customized and programmable for any master / sub screen display, keyboard lighting, general status signal or Flash signal. In order to achieve the maximum brightness of the white LED, the matching rate between channels is 1%.

With an external resistor, the two flash output currents on the AAT2846 can be set up to as many as 16 stages, with each output up to a maximum of 300 mA (total current of up to 600 mA). In order to balance the power consumption, the flash current matching rate is 4%.

These two devices are integrated within the two high-performance, low noise LDO. Each LDO uses its own independent selection input to support up to 200 mA of output current. In order to achieve the basic power of various functional requirements, such as a house controller (housekeeping controller) or the camera module, the output voltage of each LDO can be programmable divider changes in 1.2V to 5V through a resistance. In the sorting of a variety of external power supply, AAT2846 and AAT2856 two independent control of LDO can increase the flexibility of system designers.

AAT2846 and AAT2856 are built with short circuit protection and over temperature protection. The soft start circuit can automatically prevent the excessive inrush current when the mode is switched on and on.

Price and supply

AAT2846 rated operating temperature range is -40 to +85 DEG C, using lead-free, 28 lead TQFN44 package; order quantity of $10000 per piece price of $1.42. AAT2856 order quantity of 10000 per unit price of $1.14.

Source: 21cnIT channel