Power Electronics

Adding Value to Power Management Semiconductors

Wouldn't it be great if power management could create a consumer buzz just by placing a sticker on notebook PCs that reads, “Powered by Company X?” Don't hold your breath. Most system-level designers view power management as a necessary evil that adds cost, size and heat to their box, which needs to be minimized and never heard from again once the design is complete. This attitude can lead to commodization and standardization of components, which stifles innovation and, hence, long-term growth of the end markets.

Although this scenario sounds bleak for power management suppliers, there are always a host of cutting-edge driver applications that force power innovation and the generation of value from semiconductor suppliers to their customers. As digital technologies expand, shrink and pack more transistors on a single die, the challenges of power management increase exponentially. Applications driving power management product innovation include high-end servers and the PC, distributed power, POL communication and interaction, power-over-Ethernet (PoE) and dense, highly efficient extended battery life portable electronics.

Each application provides its own power management challenges that are driving innovation. High-current multiphase designs still present the largest challenges. As output voltages consistently approach and break the 1-V level, efficiencies are being challenged (at sub 10% duty cycles to minimize distribution losses), and accuracy requirements (<0.5% ≤ ±5 mV) are getting to a point where conventional methods are no longer satisfactory.

Although some designs have focused on programmable voltage flexibility, output current is the most difficult to predict and the most expensive and time-consuming to change once the design is set. Scalable multiphase solutions address this by simplifying designs and offering the ultimate flexibility in determining key design tradeoffs such as cost, efficiency and size. Current sharing accuracy has become a critical parameter at these current levels to achieve highest efficiencies in the smallest space. Maintaining a tight load line is proving problematic as currents increase and converter output impedances drop. This requires new current sense techniques as conventional RDS(on) sensing is rendered useless and inductor DCRs shrink.

As transient requirements cross 1000 A/μs, faster operating frequencies, new control methods and better capacitor technologies are needed. One controversial topic is digital versus analog control. Other breakthroughs in power density and thermal transfer through innovative semiconductor packaging are changing how power is designed.

Also driving innovation are distributed power approaches with dc bus implementations, and the communication, monitoring and control of POL subsystems in communications and computing. Low-cost smart control of the loads in terms of sequencing, margining, power monitoring, cycling, diagnostics and efficiency management are possible with the proper architectures. Communicating this information to the system lets it optimize all aspects of power and performance. This trend is bringing digital communications to the world of analog, further pushing the convergence of the two and potentially leading to full digital solutions as the mainstream of power management.

As consumer electronics become more intelligent and feature-rich, semiconductor products are becoming more application specific, forcing system-level expertise critical to proper product definition and development of individual components in the context of the system. The recent downturn has left system integrator design staffs light, exacerbating this need, and forced system-level issues and development onto the semiconductor vendors.

Thus, semiconductor companies that have had recent success within the power management field have gained this system-level knowledge by embracing a holistic approach to power management development. They have applied this approach to architectural advancements, integration capabilities and better components within a system context. This change in thinking has allowed faster improvements in the management and control of power at a system level. Nevertheless, the industry must set a more aggressive roadmap to meet consumers' insatiable demands for the future.

Prior to joining IR in 2001, Tim Phillips held positions at ON Semiconductor and Cherry Semiconductor. He earned his BSEE and MBA from the University of Rhode Island.

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