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National Semiconductor Introduces Industry’s First Average-Program Load-Share Controller

LM5080 Simplifies Paralleling of Power Supplies

Oct 18, 2005

October 18, 2005 - National Semiconductor Corporation (NYSE: NSM), a worldwide leader in power management technology, today introduced a load-share controller IC for balancing currents from parallel power supplies in a variety of distributed power applications, including telecom and data communications systems.

The LM5080 implements the average program method of active load-share control, which adjusts the output voltage of individual power supplies either up or down to deliver nearly equal currents to a common load. This technique improves stability and output voltage tolerance compared to other load-sharing methods.

“Competitive solutions utilize the master-slave method of active load-current sharing, where the highest output voltage supply dictates the output voltage to the others.  In contrast, the LM5080 utilizes a unique method of active load-share control that adjusts the output of each module to an average value,” said Paul Greenland, director of strategic marketing for National Semiconductor’s Power Management Group.  “This allows designers to operate multiple power supplies in parallel, ensuring the load current will always be equally distributed amongst them.  As system power requirements change, power supplies may be added or removed, allowing a modular design approach that saves development time.”

About the LM5080
The LM5080 is a versatile load-share controller that provides all the functions required to balance the currents delivered from multiple power converters operating in parallel.  The LM5080 supports two common applications for load-share controllers: external control, in which the load-share circuit balances currents between separate power modules; and internal control, where the load-share circuit is integrated into the voltage regulation loop of each power converter module or circuit.

The LM5080 also features:

  • No precision or matched external resistors are required, reducing component count and cost
  • Wide input voltage range allows the LM5080 to operate from bias voltages as low as 3V or up to 15V
  • It is adaptable for high- or low-side current sensing, allowing the LM5080 to be used with a variety of current-sensing configurations
  • A flexible architecture with four operating modes allows the LM5080 to control load sharing using the positive remote sense pin, negative remote sense pin or the trim pin of the power module
  • Single-wire current-share bus connects and controls multiple LM5080 devices and eases design of the printed circuit board

About National’s Power Management Products
National Semiconductor is the number one supplier of power management ICs with 14.1 percent market share, according to iSuppli’s 2005 voltage regulator/reference survey.  National’s power management revenue grew 37.3 percent in 2004 over the previous year, compared to 24 percent growth for the industry.  National's innovative power management products include best-in-class linear regulators; power monitoring, control and reference ICs; and switching converters, such as high-voltage ICs for DC-DC conversion, switched capacitor converters, lighting management ICs and inductive switching converters.  National also offers online tools that enable power designers to select the best power management chips for their applications.  National's Webench® design tool allows designers to choose a product, create and analyze a design, and then build custom prototypes that can be delivered within 24 hours.  More information about National’s power management products is available at http://power.national.com.

Pricing and Availability
Available now, the LM5080 is priced at 60 cents in 1,000-unit quantities.  For more information about the LM5080, including how to order samples, please visit http://www.national.com/pf/LM/LM5080.html
Note to Editors:  To view a high-resolution downloadable photo of this product, visit National's photo gallery.

About National Semiconductor
National Semiconductor, the industry's premier analog company, creates high-value analog devices and subsystems.  National's leading-edge products include power management circuits, display drivers, audio and operational amplifiers, communication interface products and data conversion solutions.  National's key analog markets include wireless handsets, displays and a variety of broad electronics markets, including medical, automotive, industrial, and test and measurement applications.  Headquartered in Santa Clara, California, National reported sales of $1.91 billion for fiscal 2005, which ended May 29, 2005.  Additional company and product information is available at www.national.com