Miniature control IC for energy-efficient white-LED backlights simplifies circuit design

September 29, 2011 // By Christoph Hammerschmidt
STMicroelectronics has extended its portfolio of energy-saving solutions for mobile devices with an IC that simplifies the design of power-efficient LCD and keypad backlights comprising white LEDs.

Backlights built with white LEDs instead of traditional fluorescent tubes consume less power and thus enable longer battery life for portable devices such as smartphones, games and GPS terminals. ST's new chip, the STLA02, improves backlight design by performing high-side current sensing, which allows the backlight negative (low-side) terminal to be connected directly to ground with no need for a low-side sensing connection. This simplifies pc-board design, reduces wired connections to the backlight, and increases system reliability.

The STLA02 can drive up to six LEDs and can operate from a supply voltage as low as 2.5V, allowing its use in systems powered by only a single lithium cell. The maximum input voltage of 18V also allows use with a variety of other battery types.

 The STLA02 expands ST's already large portfolio of devices that help reduce size and increase battery life in feature-rich portable products, leveraging in-house process technologies for class-leading integration and power efficiency. These include highly efficient DC-DC converters, audio ICs and class-D amplifiers, ambient light sensors, motion sensors, and high-performance low-power microcontrollers such as the STM8 and STM32 families.

Key features of STLA02 are boost (step-up) DC-DC converter topology, a wide battery supply voltage range of 2.5V to 18V and a maximum LED driving voltage of 27V. The PWM dimming range is 300: 1. Over-temperature and over-voltage protection are integrated.

The STLA02 is in full production in the 6-lead DFN6 package, priced from $0.892 for orders over 1000 units. Alternative pricing options may be available for larger quantities.

For further information please visit www.st.com/vregs