LED drivers for cellphones, smart phones

National Semiconductor's family of LED integrated circuit drivers are specifically designed for sharper colours and superior brightness in lighting systems for portable handheld devices.

National Semiconductor's new family of light-emitting diode (LED) integrated circuit drivers specifically designed for sharper colours and superior brightness in lighting systems for portable handheld devices such as cellphones, smart phones, global positioning systems and PDAs.

National's new LED products are also suitable for portable games, toys, MP3 players and other devices.

To accelerate system implementation, each LED driver in National's new product family offers easy design-in capability with minimal software programming.

"National Semiconductor has long been a leader in bringing exciting new functionality to market for makers of cell phones and other portable electronic devices?, said Peter Henry, Vice President for National's Portable Power Products Group.

"Our new family of LED lighting drivers - including the industry's first audio-lighting synchronised colour LED driver - will enable systems manufacturers to offer users more fun and functionality than ever before possible.

These new products truly bring the sight and sound of information to portable devices?.

National's new LP3950 is the first chip on the market to offer an audio synchronisation feature.

With this feature, the colour LEDs on the phone or MP3 player blink and change colour in time with the device's music or ring tones.

The LP3950 synchronises the LEDs based on the music's amplitude or frequency response.

For manufacturers or consumers these modes together with several sub-modes and a colour pattern generator give a freedom to differentiate and define unique colour response to any type music played with phones.

Two RGB LED outputs can drive up to 300mA of output current for colour LEDs or even for camera flash LED.

An integrated boost convertor powers the LEDs with high efficiency.

The LP3950 is offered in 32-pin thin CSP package (5.5 x 4.5mm); the price is $1.80 each in 1000-unit quantities.

National's new LP3942 is a colour LED driver with a charge pump and an SPI interface.

The driver has 16 colours with eight brightness values.

Two separately programmed outputs can either drive one or more RGB LEDs in parallel.

The product's charge pump features 1.5x and 2x modes for better colour and brightness controls in different types of LEDs.

A small 4 x 4mm LLP package and few external components enable a small solution size for any portable application.

The LP3942 is available for $1.50 each in 1000-unit quantities.

National's new LP3931 is a colour LED driver with magnetic boost convertor and SPI interface.

This chip enables OEM customers to create systems that can control the colour, keypad and camera flash with a single chip, while using the existing standard white LED drive for backlighting.

The driver's RGB functionality is similar to that in National's LP3933 and LP3936.

Each output port can be controlled separately with programmable start and stop time, slope and brightness.

The blinking cycle is also programmable.

This high-current convertor (up to 300mA) ensures sufficient current for flash LED in camera phones.

The LP3931 is available in a 4 x 4 mm LLP package; the price is $1.70 each in 1000-unit quantities.

With a 64% share of the global market, National Semiconductor is the world's leading supplier of lighting for colour displays in cellphones, according to market research firms Display Search and IDC.

According to year-end market data for 2003, approximately 520 million cellphones were sold worldwide.

As cellphones continue to evolve into smart phones, the need for LED drivers is expected to increase.

For example, today's cellphones typically use two to four LEDs.

Larger 3G phones will require up to eight LEDs to meet device lighting needs.

National supplies a complete portfolio of lighting solutions to address these expanding requirements.

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