Power Electronics

Part Two: Where Have All the Gurus Gone?

The story of the people who developed power supplies over the last several decades continues in this second part. In the previous article we covered the progress from linear power supplies to switchers and the move of power conversion from a central system location to power-conversion devices mounted on circuit boards. This transition is often described as a move from a centralized power architecture to a distributed power architecture (DPA).

As the market demanded numerous voltages on a single circuit board, the power-system architecture evolved into the intermediate bus architecture (IBA). Another form of distributed power architecture, IBA employs an isolated dc-dc converter to provide the bus voltage to many nonisolated dc-dc point-of-load converters (POLs) located next to the devices they power. Artesyn, with the capacity of low-cost overseas manufacturing, quickly dominated that market.

Around 2000, Power-One, sensing the need to combine power conversion, control and communication into a single, easy-to-use system set up shop in a new Silicon Valley location. There it developed a family of digitally controlled POLs and devices to manage them.

To execute the development of digital POLs and power management requires the combined disciplines of digital semiconductor design and analog dc-dc converter design. At Power-One, two key individuals, Dennis Roark and Alain Chapuis, with a team of digital semiconductor designers developed the first digital POL power conversion and management system and introduced it in 2004, two years ahead of the competition.

At the same time, Patrizio Vincerelli, working on a stealth project, developed the factorized power solution that attempts to turn the whole approach to on-board distributed power on its head. Most IBA systems normally have a single isolated dc-dc converter providing the bus voltages to the nonisolated converters placed next to the ICs. Vicor’s system, on the other hand, distributes higher nonisolated voltages across the circuit board to power isolated converters placed close to the devices they power.

The announcement of Vicor’s disruptive factorized power and the disruptive digital power conversion and management by Power-One were made at about the same time.

A year later, Artesyn and a consortium of other companies responded with a more robust communication and control specification protocol, based on an older two-wire Philips I2C communication protocol. They named it the PMBus. At about the same time, Artesyn announced its first 20-A PMBus-compatible POL (DPL20C) for which, as of today, no product or datasheets are available. Power-One responded by firing a shot across Artesyn’s bow with a lawsuit claiming multiple infringements of Power-One’s intellectual property (IP) patents.*

With the wide acceptance of digital power conversion and control, the development of new devices requires the participation of many disciplines such as analog and digital designers, digital programmers, ASIC designers, and semiconductor processing and fabrication facilities. The gurus of the past cannot do it alone and, rather than bending over laboratory benches, they are now managing large development teams.

Whether their innovative skills will allow them to be as effective in managing as they were in developing new products remains to be seen. My prediction is that in the future we will hear from the old gurus and from many newcomers joining their exclusive club.

With the linear, the switcher, distributed power, IBA, and digital power conversion and management behind us, we still have a long way to go. We need to refocus our efforts from just individual power-conversion efficiencies, presently in the high 90 percentile, to the overall system reduction of energy usage.

Digital conversion and management, with its ability to efficiently control the power-conversion devices, will allow system designers to turn devices on and off as needed for better energy-efficient system operation. We also need to work more closely with the semiconductor processing companies who, after all, are the main users of the bulk power we provide.

I am sure I have omitted several people that contributed to the progress of the power-conversion industry. Memory has a funny way of getting fuzzy over time, and my apologies if I omitted some contributors or did not describe some of the events accurately. Please let me know and I will include your comments in a future column.

*Editor’s note: Lou Pechi is a former director of market development at Power-One.

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