Digital Power Q&A

Jan 2, 2007 11:45 AM

In the previous installment of the Digital Power Q&A, representatives of the semiconductor industry were asked, “What are the obstacles that prevent adoption of digital power technology?” In this edition of the Q&A, the same question is posed to experts from the power supply industry.

Answers:

Stephen Oliver
Vice President of Marketing and Sales, V·I Chip Division
Vicor

“Flexibility is the keyword. Actual power conversion is the easy part – direct 48-V to 1-V conversion at 91% in 91A/in2 is a given. The difficult part is making sure that all parts of the system communicate flexibly and correctly to ensure maximum uptime and efficient energy transformation. This means that common, ‘open’, non-proprietary protocols—like PM Bus—and simple physical interfacing—e.g. serial rather than parallel ports—are required. Servers and telecom applications have different demands, as do individual customer systems, so flexibility to easily adjust the communication elements of powertrain components is critical.”

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Peter Resca
Director of Engineering
Astrodyne

"While we are optimistic about the future of digital power management, for several reasons I don't believe that the technology is suited for early adopters. First, today many applications don’t require the functionality, flexibility and monitoring that digital provides. Second, without the need for the added functionality, there is no compelling reason to absorb the added cost when less expensive options are available. Third, there is industry dissension with no agreed upon common standard. Until these issues are resolved, many are adopting a 'wait and see' posture."

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Todd Hendrix
Consultant & Electronics
Industry Veteran

"The impediments can be simply stated: one, installed base; and two, resistance to change. By 'installed base' I mean that power designers are providing power solutions today that meet the needs of their end application. They select from a plethora of PWMs or modules to satisfy their power conversion requirements. External silicon is then used to control or monitor the power supply.

'Resistance to change' should not be negatively interpreted: it just means we have something that works and don't yet have the motivation to learn a new approach. While early adopters usually blaze the trail, the rest of us tend to wait. We are finally won over when our present solution no longer works or becomes obsolete, the new solution appears less expensive, or we become overwhelmed by the ease of use and broad availability.

As goes human nature, goes the adoption of digital power technology."

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Mike Wagner
Vice President of Marketing
Cherokee International

"At Cherokee, we do see some application benefits for digital control and are pursuing implementation of digital control in new power supply designs. However, there are obstacles to the deployment of digital control that the industry should address. To start, the power supply community needs to better communicate real-world benefits and trade-offs to end OEMs. Another concern is the lack of a digital controller available for current-mode ZVS—implying voltage-mode implementation that adds cost and complexity (e.g. volt-sec balance on the transformer). Another important point is that analog engineers are not familiar with working with Z transforms, which are required for digital control. Of course, there are many other issues that must be addressed."

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Kulbir Dhillon
Director of Business Development
C&D Technologies

"Digital control provides the ability to optimize product and system performance during the design and qualification phase of development. Once this is achieved the benefits of digital control become marginal, especially if there is added cost of implementing a digital solution. In complex applications this cost performance trade-off may be justified.

The true power of digital control will be realized when the implementation of such a technology provides self-correcting parametric performance where the power-delivery system combined with higher-level system management optimizes voltage, efficiency, thermal performance, and predictive failure modes in-order to deliver a robust and reliable solution."

Want to share your opinion with the world? E-mail the editor, and have your thoughts on making the leap from analog PWM controllers to digital PWM controllers posted here.