20-V synchronous buck controller drives high-current point-of-load applications

July 06, 2010 // Paul Buckley

National Semiconductor Corp. has unveiled a new synchronous voltage-mode buck controller that drives a variety of high-current point-of-load applications in printers, telecom, networking and embedded computing applications.

A new addition to National's PowerWise energy-efficient product family, the LM27402's advanced features make it the industry's most feature-rich 20 V synchronous buck controller. Until today, point-of-load controllers have incorporated one or two complex features, such as a wide input voltage range, integrated high-current gate drivers with adaptive dead-time, inductor DCR current sensing or on-chip bias supply sub-regulator. National's LM27402, however, is the first universal point-of-load controller to integrate all these advanced features into a single chip - key features required for many types of DC-DC applications.

A wide input voltage range of 3 V to 20 V allows the LM27402 to interface with all intermediate bus voltages, including 3.3 V, 5.0 V and 12 V rails. Integrated inductor DC resistance current sense eliminates the need for resistive power train elements to detect output current. This increases overall power conversion efficiency and allows accurate continuous current limit sensing. The current sense threshold level is programmable to accommodate a wide range of load current levels using the smallest inductor possible.

Output voltage is adjustable down to 0.6 V with a one percent voltage reference providing output voltage set-point accuracy over the full -40 to 125 degrees C operating temperature range. An integrated bias supply sub-regulator eliminates the external bias voltage supply to simplify PC board layout. Integrated, high-current MOSFET gate drivers with adaptive dead-time control enable ultra-efficient power conversion with load currents as high as 30 A. It also supports programmable soft-start, tracking and pre-biased startup.

Offered in 16-pin thermally enhanced TSSOP and 4 mm by 4 mm LLP packages, the LM27402 is available for design on National's WEBENCH Power Designer.

Availability and Pricing

Available now, National's LM27402 is priced at 1.68 US Dollars in 1,000-unit quantities.

Related link: LM27402

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