Achieves improved backlighting of color LCD panels in mobile products

Tokyo -- Toshiba Corporation today announced the commercialization of an LED driver IC that raises the operating efficiency of white LEDs to 85%. The new driver IC supports highly efficient back lighting and improved performance of LCDs installed in a wide range of mobile products.

Samples of the IC, TB62731FU, will be available from September 2001 at a sample price of 100 yen. Mass production will start in October 2001, at an initial monthly volume of one million units.

Key to the performance of the driver IC is a current drive technology that maximizes operating efficiency and pushes performance by 20%. The result is the choice of a 20% decrease in power consumption while maintaining LED emissions at the same level as in current products, or maintaining power consumption at present levels and boosting LED emissions by 20%. The IC is also the first to adopt a driving current derating function and develop circuit of predicting ambient temperature, allowing it to measure power consumption against heat and so maximize LED performance at room temperature. The IC can be simply optimized to support a wide range of applications, from cellular phones to PDAs.

Background of Development

The market trend is to personal products--cellular phones and PDAs--with color LCDs. Manufacturers supporting these markets have to achieve two goals: a long battery life and high product performance. The display and its back lighting are a major drain on power. Toshiba seeks to address this problem with its new white LED driver, which offers increased efficiency in display brightness and power consumption.

Toshiba is also seeking to reinforce its business in mixed signal ICs that handle both digital and analog data, and is working in this with AC Technologies Corporation, a semiconductor design and development company specializing in analog-based semiconductor. TB62731FU is the first result of this cooperation.

Major Features of TB62731FU

• Newly developed electric current drive mode raises light emission efficiency to 85% at minimum power. This new methodology substantially eliminates series resistance that raises power consumption, allowing turn on of several white LEDs in serial connection.
• Newly developed temperature derating technology predicts environmental temperature, including that from the driver IC itself, and optimizes light emission.
• Either of direct-current turn on mode or pulse-current turn on mode can be supported, depending on the application and LED characteristics. Pulse-current turn on mode offers higher efficiency, as it requires fewer diodes and condensers than D.C. mode and is more efficient in LED turn on in high forward current.
• Adoption of BiCD process technology reduces external components. It also contributes to the low power consumption required in mobile product and realization of an easy-to-assemble SOT23-6pin package.

Major Specifications of Driver ICs