National Semiconductor’s New Lighting Management Units Drive up to 20 Series-Connected LEDs in Cell Phones, Other Handheld Devices

National Semiconductor's New Lighting Management Units Drive up to 20 Series-Connected LEDs in Cell Phones, Other Handheld Devices

National Semiconductor Corporation (NYSE:NSM) has introduced two new, highly integrated lighting management units (LMUs) that include a high-voltage boost converter and programmable constant-current driver to control up to 20 series-connected LEDs in display backlights, and keypad, RGB and camera flash LEDs. The LP3958 and LP5526 LMUs feature tiny micro SMD packages and are well-suited for cell phones and other handheld devices.

Duo of Tiny Devices Features High-Voltage Boost Converters, Programmable Constant-Current Drivers
National’s new LMUs drive from two to five strings of four series-connected LEDs, depending on the lighting application. They are optimized for use in single- or dual-display phones, as well as large display PDA phones. Each features three general-purpose input/outputs (GPIOs) to trigger lighting functions such as flash or to control additional device-enable signals.

Technical Features of National’s LP3958 and LP5526 LMUs
In single and dual displays, the LP3958 LMU drives up to eight white LEDs grouped as four series-connected LEDs per string, with typically one string per display. Display backlight fade in and fade out is controlled via a two-wire, low-voltage, I2C-compatible interface, allowing easy software implementation. The GPIO functions enable the user to control external devices.