Seiko NPC Corporation has started full production of its SM8150AB power management IC (PMIC). The new product is designed to turn the backlighting white LED for color LCD panels in mobile equipment on and off. It is also capable of regulating brightness and supplying power to individual function blocks.

On the road to multi-functionality, mobile equipment—and especially mobile phones—will increasingly require greater power savings to meet the extra demands put on battery life. This translates into a need to optimize the power supply used for backlighting and the circuitry of each function.

The recently released SM8150AB is actually a single chip designed for use in a high-functionality mobile phone equipped with a camera and TV reception capability. More concretely, the chip consists of a white LED driver (four main LEDs for backlighting, two sub LEDs for backlighting, and one LED for high current flashing), a step-down DC/DC converter (for one system), and a series regulator (for two systems).

Using the charge pump method, the SM8150AB's built-in white LED driver eliminates the need for a boost coil, whose size is too large for implementing a compact design. What's more, the driver helps prolong the life of batteries because it monitors the value of drive currents flowing through all LEDs at approximately 1-second intervals and automatically sets an optimum value for the boost factor. Thanks to the I²C-bus^*1, each LED can be turned on and off and brightness controlled.

The step-down DC/DC converter, which uses PWM switching, provides high-efficiency power conversion for an input voltage of 3.6V, even when the output voltage is as low as 1.5V. The maximum supply current is 500mA. In addition, an external resistor can be used to provide output voltage so that the converter is compatible with chips that have a variety of core voltages. Uses of the converter include the power supply of TV reception blocks.

The series regulator provides a maximum supply current of 300mA and an output voltage of 1.5V to 3.3V, settable to eight different levels over the I²C-bus^*1. An example of how the regulator can be used is the camera module block.

All of the SM8150AB functions are housed in a QFN-28 package that measures 4.0mm by 4.0mm by 0.7mm. The result of this substantial reduction in installation area, in addition to the greater wiring efficiency, is mobile equipment in smaller designs.

*1:I²C-bus is a registered trademark of NXP B.V.

Name	Price with and without tax	Volume production date	Planned production
SM8150AB	400 yen/unit (420 yen/unit)	Already in full production	1 million units/month