Synchronous buck controller integrates four key features

National Semiconductor Corp. announces 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 the company's PowerWise energy-efficient product family, the LM27402’s advanced features make it a notably feature-rich 20-V synchronous buck controller.

Traditionally, 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. The LM27402, however, is reportedly 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 to 20 V allows the LM27402 to interface with all intermediate bus voltages, including 3.3, 5.0, 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 1% voltage reference providing output voltage set-point accuracy over the full -40° to 125° 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.

For more information, contact National Semiconductor Corp., 3689 Kifer Road, Santa Clara, CA 95051. Phone: (800) 272-9959.