08/03/2006 - Toshiba Electronics Europe has announced two new ultra-miniature, high-efficiency, low-noise constant current LED driver ICs (CCdriver). The TAH8N401K and TAH6N201U ‘non up-convert type’ drivers will save board space, minimise component count and reduce power consumption in backlight, indicator light, and other LED driver applications.

Non-up-convert type constant current driver ICs for white LEDs

The TAH8N401K is a 4-channel driver supplied in Toshiba’s US8 package with a footprint of 3.1mm x 2.0mm. The TAH6N201U 2- channel driver is supplied in Toshiba’s UF6 package and has a footprint of 2.0mm x 2.1mm. Both drivers have a profile of less than 0.8mm. In the simplest configurations only a single external resistor is connected to the reference voltage pin to set the drive current. This allows engineers to implement LED driver circuitry within a maximum board space of around 9mm2. As the built-in protection circuitry adjusts the LED drive current with increasing temperature no external compensation circuit is needed, contributing to further space and component count reductions. Additionally, operation of the CC-drivers in linear control mode is possible with an external PWM signal (1 to 100kHz) applied to either the control or reference voltage pin of the device. In this operation mode linear control between shutdown mode and full driving current is possible by adjusting the duty cycle of the PWM signal. Ideal for portable and battery-powered electronic equipment, the new

Application circuit example

TAH8N401K and TAH6N201U drivers operate with power supply voltages of 2.5V and 5.5V. Efficiency is in excess of 90% with a supply voltage of 3.6V. The new driver ICs are designed for parallel LED connection and can deliver drive currents up to a maximum of 25mA per channel. Maximum power dissipation is 400mW for the 4-channel driver and 200mW for the 2-channel device.

About Toshiba
Toshiba Corporation is a leader in information and communications systems, electronic components, consumer products and power systems. The company’s integration of these wide-ranging capabilities assures its position as an innovator in advanced components, products and systems. Toshiba has more than 165,000 employees worldwide and annual sales of over US$54 billion (FY2004). Toshiba Electronics Europe (TEE) is the European Headquarters for the electronic components business of Toshiba Corporation, which is the world's fourth largest semiconductor vendor according to estimates by Dataquest. Providing design, manufacturing, marketing and sales, TEE was formed in 1973 in Neuss, Germany. The company now has headquarters in Düsseldorf, Germany and subsidiaries in France, Germany, Italy, Spain, Sweden and the United Kingdom. Company president is Mr Shikama and the total number of personnel in Europe is around 400. Toshiba Electronics Europe offers one of the industry's broadest IC and discrete product lines including high-end memory, microcontrollers, ASICs, ASSPs and display products for automotive, multimedia, consumer, telecoms and networking applications. The company also has a wide range of power semiconductor solutions.

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