LM5032 and LM5034 Can Control Two Independent Regulated Outputs or a Single, High-Current Output for Design Flexibility
The LM5032 and LM5034 are flexible controllers that can be configured to control either two independently regulated outputs or a single, high-current output from two primary power stages. In the first case, the two PWM channels operate 180 degrees out of phase with one another, or are interleaved, which reduces the input ripple current. In the single-output configuration, the interleaving also reduces ripple current in the output filter capacitor. The LM5032 controller can be used for designing dual-interleaved boost, flyback or standard forward converters. The LM5034 controller is specifically designed for interleaved forward converters with active clamp transformer reset.
"The LM5032 and LM5034 are National's first products designed for interleaved isolated single-ended DC-DC converters, allowing users to implement interleaved single- or dual-output supplies," said Paul Greenland, director of product marketing for National Semiconductor's Power Management group. "Interleaved power conversion is increasingly useful, especially in dense, high-power applications that require significant filter capacitance to manage high-input peak switching or ripple current."
National is demonstrating the LM5032 and LM5034 at the Applied Power Electronics Conference and Expo (APEC) in Austin, Texas. The exhibit is open through March 9 at the Hilton Austin Downtown Hotel. National's product demonstrations will be held in booth 606/608. For more information on National's products and speakers at APEC, please visit http://www.national.com/events/ .
About the LM5032 and LM5034
The LM5032 and LM5034 are highly integrated devices, providing two complete, independent current-mode PWM controllers with separate soft-start and control pins. They give power supply designers the flexibility to design power converters with either dual independent output voltages or a single, high-power output. In both cases, the primary power stages operate 180 degrees out of phase. This phase-shifted interleaving of the power stages allows a reduction in the size and cost of bulk input- and output-filter capacitances. Other integrated features include a high-voltage start-up regulator that operates over a wide input range of 12 V to 100 V, as well as cycle-by-cycle current limit, slope compensation and over-temperature protection.
The LM5032 and LM5034 also feature a fast propagation delay of less than 100 nS and a 2 MHz-capable, single-resistor-adjustable oscillator that can be synchronized externally. Both chips integrate two of National's compound, bipolar-CMOS, 2.5 A MOSFET gate drivers. The LM5032 and LM5034 also feature user-adjustable maximum duty cycle, hiccup-mode fault protection with adjustable restart delay, adjustable input under-voltage sensing and a direct opto-coupler interface.
The LM5034 provides two additional gate drivers for P-channel active-clamp MOSFETs with user-programmable dead-time control. Active-clamp transformer reset achieves superior conversion efficiency compared with conventional single-ended power supply topologies.
Pricing and Availability
The LM5032, in a TSSOP-16 package, is priced at $1.55 each in 1,000-unit quantities. The LM5034, in a TSSOP-20 package, is priced at $1.90 each in 1,000-unit quantities. More information about the products is available at http://www.national.com/pf/LM/LM5032.html and http://www.national.com/pf/LM/LM5034.html .
About National's Power Management Products
National Semiconductor is the number one supplier of power management ICs with 12.8 percent market share, according to iSuppli's 2004 voltage regulator/reference survey. National's power management revenue grew 29.7 percent in 2003 over the previous year, compared to 17.3 percent growth for the industry during the same time period. 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's WEBENCH(R) online design tool allows designers to select a power management 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/ .
About National Semiconductor
National Semiconductor, the industry's premier analog company, creates high-performance 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 markets include wireless handsets, displays, PCs and laptops. The company's analog products are also optimized for numerous applications in a variety of electronics markets, including medical, automotive, industrial, and test and measurement. Headquartered in Santa Clara, California, National reported sales of $1.98 billion for fiscal 2004, which ended May 30, 2004. Additional company and product information is available at http://www.national.com/.
NOTE: WEBENCH and National Semiconductor are registered trademarks of National Semiconductor Corporation. All other brands or product names are trademarks or registered trademarks of their respective holders.
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