Digital power controllers

New generations of digital power controllers can help engineers meet complex design challenges

BY LUCY A. SNYDER

Electronics designers must contend with complex power management needs. Consumer demand for ever-smaller energy-efficient products often results in engineers having to figure out novel ways to deal with cramped board spaces and excess heat. Device redesigns frequently demand features such as dynamic voltage scaling, margining, tracking, sequencing, system fault detection, and response. New devices must often incorporate features such as multiple voltage domains and maintain fast transient responses and high efficiencies over wide load ranges.

Many applications for digital power controllers

Consumer demands aside, energy efficiency is especially important now that regulations are becoming more stringent, and device reliability must not be compromised. Fortunately, for every power management requirement, there is a digital power controller on the market to meet these design challenges.

Many suppliers meeting different digital power needs

For instance, Summit Microelectronics offers the SMB119 seven-channel programmable dc/dc power manager. The SMB119 is intended for a wide range of portable electronics such as video camcorders, media players, PDAs, and cell phones. Its seven channels include three step-down buck converters, one programmable step-up boost or step-down synchronous buck converter, two step-up converters, and one linear regulator (LDO).

Texas Instruments offers the UCD9240 fusion digital power controller. This configurable controller integrates dedicated circuitry for dc/dc loop management with flash memory and a serial interface. It can control up to four voltage rails and eight phases, and it is intended for applications such as Ethernet and wireless routers, hubs, servers, external and internal hard-disk drives, and telecommunications devices. It works with Fusion Digital Power Designer, a PC software package that aids in power supply design, simulation, configuration, and performance monitoring.

Infineon offers several digital power management products. Its Core Control group provides a wide range of low-voltage ICs for products requiring high energy efficiency, such as desktop computers, laptops, servers, telephones, and VRM modules. The Core Control PWM control ICs, which are intended for use in computers, offer two-to-four Phase PWM conversion with automatic phase selection, programmable switching frequencies, and other features for dc/dc voltage regulation.

Volterra Semiconductor offers multiphase point-of-load (POL) integrated circuits and VRMs in their silicon power solutions line. Their power managers combine integrated power, analog, and digital circuits on a single CMOS chip, which is intended to vastly reduce the number of discrete power components needed on a single board.

Power-One’s Z-One series provides bus-programmable POL integrated circuits with outputs from 0.5 to 5.5 V and 5 to 60 A. The devices feature a digital power manager (DPM) that allows designers to program output voltages, sequencing, tracking, and protection limits through a graphical user interface. The DPM can control up to 32 digital POLs as well as several third-party components.

Fewer components, smaller size

Fairchild Semiconductor’s Digital DC series composed of its FD2004, FD2004-01, and FD2006 digital power controllers and their FD1505 digital power support driver are intended as universal power building blocks for computing and telecommunications applications. These products combine digital loop control with integrated power management capabilities and can accommodate an input voltage range from 3.0 to 14 V and control output voltages from 0.54 to 5.5 V.

The FD2006 and the FD2004 both offer single-phase dc/dc control and incorporate a single-wire DDC bus (Digital DC bus) for current sharing and inter-device communication. The FD2004 is also compatible with external MOSFETs and driver FETs and offers DCR (Direct-Current Resistance) current sensing with an adjustable current sense range. The FD1505 offers high-speed, high-current synchronous n-channel MOSFET drivers and independent high-side/low-side PWM control with an improved pre-bias and diode emulation mode control. The FD2106 is the smallest 6-A buck converter with integrated management, and it features internal synchronous MOSFETs and a boost diode along with sequencing, tracking, margining, monitoring, and fault management.

DC-DC controller with integrated drivers.

All the controllers in the Digital DC series include on-board I2 C/SMBus-compliant serial port and support the industry-standard PMBus (Power Management Bus) command set. The controllers can also be used alone or connected in parallel, and they include proprietary algorithms that dynamically optimize energy efficiency as operating conditions change.

Improved power control

Fairchild estimates that these new algorithms result in a full-load efficiency improvement up to 3% and a light-load efficiency increase greater than 15% in typical applications. This in turn reduces peak power dissipation by up to 20% and significantly increases the overall performance of telecom, computing, and data storage devices. These energy efficiency gains address the growing concerns of meeting new Climate Savers Computing and Energy Star and efficiency guidelines.

Power control in the Digital-DC series is made even easier with bundled software tools. The devices come with PowerNavigator software licensed from Zilker Labs, which allows engineers to configure and monitor many USB-interfaced devices through their PCs. The CompFD simulation tool is also included; among other features, this software automatically calculates loop compensation settings.

Clearly, manufacturers have made a variety of advances in digital power controller technology. Whether you are seeking solutions to problems related to hot or overcrowded circuit boards, or you are looking for ways to improve energy efficiency and meet greener guidelines without sacrificing performance, or you’re simply looking for more advanced ways to design and manage power systems within your products, there’s a controller available to meet your needs. ■

Visit http://powercontrollers.electronicproducts.com to see full coverage of digital power controllers. Fairchild Semiconductor is a global leader delivering energy-efficient power analog and power discrete solutions. Fairchild plays a pivotal role in answering design issues that conserve energy with energy-efficient products that address the many critical environmental challenges that face the world today. Fairchild is The Power Franchise, providing leading-edge silicon and packaging technologies, manufacturing strength and system expertise for consumer, communications, industrial, portable, computing and automotive systems. An application-driven, solution-based semiconductor supplier, Fairchild provides online design tools and design centers worldwide as part of its comprehensive Global Power Resource. Please contact us on the web at www.fairchildsemi.com. Visit http://powercontrollers.electronicproducts.com to see full coverage of digital power controllers Sponsored by Fairchild Semiconductor • www.fairchildsemi.com