Product category: Power Supply ICs and Controllers
News Release from: National Semiconductor | Subject: LP3958 and LP5526 LMUs
Edited by the Electronicstalk Editorial Team on 29 June 2006
Managers take control of lighting levels
Lighting management units include a high-voltage boost convertor and programmable constant-current driver to control up to 20 series-connected LEDs.
National Semiconductor has introduced two new, highly integrated lighting management units (LMUs) that include a high-voltage boost convertor 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 cellphones and other handheld devices
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
Related stories
Dual-port Gigabit Ethernet transceiver
National Semiconductor has announced the DP83862, a low-cost, highly integrated dual-port 10/100/1000 physical layer transceiver.
World's smallest multifunction supervisory ICs
National Semiconductor has announced a family of supervisory ICs with a variety of factory-programmable features that can be configured in hundreds of possible combinations.
National's new LMUs drive from two to five strings of four series-connected LEDs, depending on the lighting application.
They are optimised 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.
The LP3958 features 70mA of output current for powering display backlight LEDs and the LP5526 features 150mA of output current for powering display backlight and Flash LEDs.
Both devices include an I2C interface.
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.
The serial interface reduces the wire count through the hinge in flip cellphone designs.
For keypads, three series-connected LED strings of up to four LEDs each can be independently controlled to enable light segmentation.
This is particularly useful in gaming and navigation applications, for example, in which individual buttons can be selected for illumination.
The LP5526 has the same features and packaging as the LP3958 and can drive multi-die serial-flash LEDs in camera Flash (up to 3W of power) and torch applications.
Also, in the case of a software problem, the LP5526 features an internal safety timer to protect Flash LEDs from aging.
With the LP5526, the Flash LED output can also be used to drive single or series-connected RGB LEDs.
• National Semiconductor: contact details and other news
• Email this article to a colleague
• Register for the free Electronicstalk email newsletter
• Electronicstalk Home Page
Search the Pro-Talk network of sites
