Bench Talk

Solving the Power Module Design Dilemma: Make Vs. Buy in Constrained Volume Applications Like Mobile/Portable Electronics

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Even a decade ago, electronic systems only required a few different supply voltages and currents, and these were typically shared among various circuits. Also, unlike electronics from a decade ago, modern electronics design often emphasizes extremely compact designs and mobile/portable solutions. The latest field-programmable gate arrays (FPGAs), multi-processor central processing units (CPUs), graphics cards, and RF/wireless hardware often require a complex array of DC power supplies. That diversity and density of required power supply solutions are vastly beyond that of prior generations of mobile or portable electronics. This complexity places a quandary on system and power designers alike, either to make discrete DC-DC power supply circuits in-house in a traditional fashion or to purchase power modules and integrate them into the design (i.e., make versus buy).

Let's explore the latest power module solutions and how they may finally tip the balance in favor of the buy argument regarding high-density or volume/footprint constrained power system design.

In-house design and fabrication of a discrete power solution require a high level of readily available expertise along with the procurement/supply chain capability of sourcing all required parts and ensuring the quality of the parts and fabrication. This is ultimately the main limitation for many OEMs, as this approach requires a team of engineers and technicians to design, evaluate, test, and manufacture the solution. Even with a crack design team, the test and manufacturing portions require their own set of specialized equipment and tools, which many OEMs may or may not have available. Even if these resources are at hand, the complexity of the modern power solutions for the latest digital and RF electronic systems may be beyond the capacity of what an OEM may have access to in-house.

Suppose an OEM does have all the necessary resources to make a complete power solution and perform all the required validation and quality control. In that case, there are still a variety of factors to take into consideration when approaching a power design that may weigh in favor of purchasing a power module.

Key factors and considerations in the power solution make vs. buy analysis:

• Size
• Weight
• Power density
• Efficiency
• Flexibility
• Scalability
• Design cycle
• Thermal management
• Assembly

The latest quality power modules on the market are designed and fabricated by dedicated teams of highly skilled engineers and technicians. These modules have also gone through many optimizing iterations and benefit from deep insights and customer feedback. Hence, these power modules are extremely compact and efficient. This means that the power density of these modules is likely far beyond what an in-house power design team can achieve in the limited time they have to get a product to market while being competitive (Figure 1).

Figure 1: The power module illustration shows how the efficient use of space can result in a much smaller and power-dense solution. (Source: Vicor)

Given the dedicated nature of power module design teams and their many resources, the latest premium modules also come with various features that intrinsically allow for flexibility in the design and scalability. Moreover, dedicated power module designers can benefit from the latest power IC design knowledge and can now offer modules that leverage the best performance combinations in the smallest packages. Not only does this efficiency ease thermal management in general, but the new uniform planar packaging and module design greatly simplifies thermal management heat sink and/or active air-cooling design (Figure 2).

Figure 2: A power module procured solution can have a much smaller footprint and offer higher efficiency than typical discrete power solutions. (Source: Vicor)

Edge electronic systems for processing, sensing, and actuation connected wirelessly to information networks are a growing trend. This coincides with a trend of electronic manufacturers struggling to stay relevant and competitive, looking to make their products smaller, lighter, and more mobile/portable to increase their value to end users. These latest edge and portable electronic solutions are under extremely tight size, weight, and power efficiency constraints, even with advances in battery technology leading to greater energy and power density.

This is because the weight and size of less efficient power electronics must necessarily increase to reach the same performance as more efficient solutions. When every ounce counts, a strong argument exists for including more efficient and compact power modules in a design rather than the in-house design of a discrete power solution that is likely much larger and far less efficient.

Vicor is a leader in high-performance power modules and invests substantially in innovating its own power module technologies to enable OEMs to generate their own innovations. Vicor power modules have proven superior to typical discrete power module solutions in every significant performance category, from size/weight and efficiency to quality and scalability.

An example of this is the Vicor Zero-Voltage Switching (ZVS) Buck-Boost Regulators. These high-density system-in-package (SiP) power modules exhibit wide input range DC-DC regulators with integrated accessory components, controllers, and power switches in a solution that is a fraction of the size of a typical through-hole inductor. The high frequency switching capability and advanced controls within the ZVS Buck-Boost Regulators results in a more compact and efficient (over 98 percent efficiency >800kHz FSW) power module. Also, it reduces the size of external filtering components to achieve the same performance as slower switching solutions. These regulators are intrinsically scalable by being parallel capable with a single wire current sharing feature.

When deciding if it is better to make or buy a power solution for a given power design, there are many factors to consider. However, the latest off-the-shelf power modules benefit from years of dedicated development and advanced features that deliver performance and density levels that are difficult or impossible to achieve with discrete power solutions in the limited time power design teams have to get their designs to production.

Principal of Information Exchange Services: Jean-Jacques DeLisle
Jean-Jacques (JJ) DeLisle attended the Rochester Institute of Technology, where he graduated with a BS and MS degree in Electrical Engineering. While studying, JJ pursued RF/microwave research, wrote for the university magazine, and was a member of the first improvisational comedy troupe @ RIT. Before completing his degree, JJ contracted as an IC layout and automated test design engineer for Synaptics Inc. After 6 years of original research—developing and characterizing intra-coaxial antennas and wireless sensor technology—JJ left RIT with several submitted technical papers and a US patent.

Vicor Corporation, manufactures and markets innovative, high-performance modular power components, from power modules to semiconductor-centric solutions, to enable customers to efficiently convert and manage power from the power source to the point of load. Vicor’s Power Component Design Methodology enables power system designers to reap all of the benefits of modular power component design – predictable component and system functionality and reliability, fast design cycles, and easy system configurability, re-configurability and scaling – while achieving system operating efficiency, power density and economy that rival the best alternative solutions.