Power converter makes for extra flash screens

National Semiconductor has developed a series of current-regulated power converters, optimised for white LED backlighting of mobile phone screens, PDAs and digital cameras.

Nat Semi says the drivers eliminate the need for inductors or resistors by regulating the power output through each LED, so that they are matched to within one percent.

Drivers include the LM2791-H/L, which has PWM ands a 5:1 ration analog brightness control, the LM2792-H/L with zero to full current control over brightness. The company says these will be used to create new effects on the displays, to add what they call "coolness" to the product.

Robert Fischer, product marketing manager at Nat Semi's portable power systems in Europe, commented: "Colour displays using white LEDs already dominate the mobile phone landscape in Japan and it is inevitable that the rest of the world will follow."

Later this year, the LM2794/95 drivers will be released as well. ®