Seiko NPC Corporation has started full production of its recently developed SM8135AB driver based on a charge pump system. The new product is ideally suited to driving white LEDs that provide the backlight for the color LCD panels used in mobile equipment.

With the trend to multi-functionality of mobile equipment (and, in particular, mobile phones), white LEDs have become popular for backlighting applications for reasons of battery life. The recently released SM8135AB has all the required flexibility for today's popular models: not only is it able to drive a set of one to four LEDs connected in parallel, it can also control the brightness of the light.

Based on a charge pump system, the SM8135AB eliminates the need for a voltage step-up coil whose outside diameter has until now prevented the down-sizing of mobile equipment. The SM8135AB also has a circuit that monitors, at an interval of approximately one second, the values of the drive currents flowing through all of the LEDS as well as automatically sets an optimum multiplier value. The result is a more efficient use of power and a longer battery life.

Still another feature is a built-in control circuit that regulates the drive current automatically. Mobile equipment that incorporates the new product will be free of the brightness irregularities on the display surface would otherwise occur from variances in the forward voltage drop (Vf). In addition, the SM8135AB's built-in smoothing filter suppresses the PWM modulation waves of the output voltage, dealing effectively with the common problem of the driver IC interfering with the signal processing section.

The SM8135AB is the latest product in NPC's effort to provide a series of products that take full advantage of element technologies.

Name	Price with and without tax	Volume production date	Planned production
SM8135AB	120 yen/unit (126 yen/unit)	Already in full production	1.5 million units/month