The Many Faces Of Custom Power

March 12, 2009
Power supplies are often the last consideration in system design, which means custom work may be involved. This article explores the many ways in which power-supply vendors can work with design teams to satisfy system and cost requirements.

Under the pressures of product performance, price, and the need to increasingly reduce their time-to-market, many OEMs don’t have the luxury of spending a lot of time on the power solution. Consequently, they look to power providers that can expeditiously accomplish their power requirements as they need them.

However, “as they need them” is the key. Suppliers can make an innovative power product. But in the end, if it isn’t in a form factor or served up the way the OEM can easily utilize in its designs, then that power product isn’t the right solution.

THE TIMES ARE CHANGING The “many faces of custom power” suggest that there is more than one way to arrive at a custom power solution. Perhaps 25 years ago, the term “full-custom” emerged to differentiate the then-standard approach from the newly introduced modular power components.

A full-custom power supply was built from scratch with discrete components, in a form factor specified by the customer, with the type of connectors that the customer wants, with the thermal considerations done the way the system allowed it to be done, whether it be conduction or forced convection, a fan in the system or a fan in the power supply. Every aspect of the design was thought out—detailed electrical, mechanical, and thermal specifications— all addressed from the ground up.

Over time, with the advent of standard building blocks, custom power took on a new face. Today, standard building blocks come in a large variety of designs—not to mention the capability of automated systems to produce custom power designs in real time. So, a custom solution can be built, not from the ground up, but with these building blocks and systems that explode time-to-market expectations, creating custom solutions that are innovative, appealing, and competitive.

The online, expert system of custom power provides mass customization capability that enables a customer to input a variable set of requirements such as input range, output set point, and output voltage within very broad limits, as well as mechanical/mounting options. The designer can, for example, enter an output voltage of 1 to 100 V or anything in between. There’s no restriction to specific outputs. If the designer wants 13.5 V, the designer can get 13.5 V. Input voltage can be anything between 10 and 450 V.

After defining the critical specifications of the module, the user then runs a feasibility check. This is a real-time-analysis of the requirements by a sophisticated expert system that creates multiple designs that meet the required specifications. If the optimal system-generated design is determined to be feasible, the user can generate a part number and a price. If an order is placed for this module, part of the expert system creates the many possible designs that meet the user’s requirements. The optimal design is then selected and dispatched to the production line.

Another face is provided by manufacturers and value-added resellers that make it their business to design, develop, and manufacture complete turnkey custom power solutions using high-density dc-dc converter modules. These manufacturers use component power in a modular, buildingblock approach that offers low cost, quick turnaround, and reliability. Because they employ power components at the heart of the design, they are sometimes termed quasi-custom power solutions rather than full-custom power solutions.

An emerging face of custom power close to home is present in the V•I Chip. Designers and application engineers work with large customers to intimately understand what the customer is up against in their system. Then they work very closely with the in-house power designers to help design the architecture and maybe even customize a specific V•I Chip for a specific application. Potentially, this work sets the stage for even further granularity, where the ability to mix and match different architectures can be realized.

DIFFERENT DEMANDS But consider that such a system might have differing requirements within itself. These systems may be taking ac in and converting it to high dc voltage. Then, they may want to bring it down to a lower bus voltage and take that bus voltage and convert it to lower voltages. Parts of the system set different requirements— such as fast dynamic response, low noise, and high efficiency—all within the same system. Or, they may want to eliminate one of those stepping stones to lower cost, minimize parts count, and improve system efficiency.

So in such a custom system, the customer could look to someone to make the right recommendations on what to use. It may not be one vendor’s power solution, and it could follow a process, such as: • It’s lower power in this section, so we can get away with a dc-dc converter.

• It’s more complex with multiple output voltages here, so we have to use the intermediate bus architecture.

• We need a factorized power architecture here because we need fast, dynamic performance.

• It must fit in a space of these dimensions.

• An L-shaped chassis is needed with ac in and three outputs at these power levels. It also has to be low profile, no more than 1U high.

The new face of custom power can extend to mixing architectures, as a consultant would, making the right recommendations for what the customer that’s building the overall system requires, all the way to actually delivering a piece of hardware.

Customization can be all about making the best choices and balancing the tradeoffs, enabling the end users, who ultimately have the best view of their needs to be able to make those decisions upfront rather than trying to live with what’s out there.

TOM CURATOLO is the director of applications engineering at Vicor Corp. He holds a BSEE from Worcester Polytechnic Institute, Worcester, Mass.

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