April/May 2021

www.vicorpower.com POWER MODULES 23 www.power-mag.com Issue 2 2021 Power Electronics Europe Figure 3: Advancements in topologies, control systems and new power delivery architectures has driven better power density for the past years and has shown a reduction in power losses of 25 % every 2.5 years, as shown by the early full-brick VI-200 DC/DC converter (left) and the latest stacked CHiP GCM and DCM modules (right) Chip® package to capitalize on further power-loss reductions, higher-frequency control systems and topologies with resulting gains in power and current density. The new package was called the ChiP™ (Converter housed in Package), and its construction and manufacturing approach broke new ground at Vicor as well as in the power module manufacturing industry. The new ChiP package was distinguished by its two-sided component assembly while being cut from fixed-size panels, similar to how silicon chips are made and cut from wafers. Key power module packaging attributes While the five pillars of innovation have driven Vicor advancements, power module packaging most acutely distinguishes the company’s expertise. There are five attributes that make a converter or regulator module package truly world-class, enabling high-performance power delivery (Figure 3). High power and current density Thermal adeptness Integrated magnetics Compatibility with high-volume PCB assembly techniques Module production using high-volume automated manufacturing techniques Each step of the power module package development leveraged new materials, active and passive components and, most notably, improvements in magnetic structures based on higher switching frequencies. The higher frequencies are enabled by topology and control system improvements incorporated in proprietary Vicor control ASICs. The recent launch of the fourth generation of these ASICs has enabled power density and current density numbers of 10kW/in3 and 2A/mm2 respectively, enabling a new family of AC and DC high-power front-end converters and point-of-load (PoL) current multipliers. These latest generations of modular power solutions are changing the way PDNs are architected and designed in both data center and automotive applications. The multi-layer circuit boards within the power module are complex designs. They require special materials for optimal thermal conduction and to manage high currents and high voltages in minimal space, all while minimizing power loss. Double-sided component placement enables heat extraction from both sides to maximize performance and power ratings. The copper-plated ChiP has further advanced ChiP packaging, significantly simplifying thermal management by means of a wrap-around copper jacket. Materials science plays a big role in advancing power package performance, especially when switching at multiple-MHz levels. The main energy storage core plays a critical role in overall module performance and can be one of the main sources of power loss in a power-system design. The core, its windings and PCB material compositions are continually optimized for higher switching frequencies, higher power levels and lower output resistances (R OUT ) to reduce power losses as current levels for a single module rise into the hundreds of Amps. By integrating the energy storage inductor or transformer into a power module and maximizing its performance, the power-system designer is relieved of the often difficult and time-consuming process of optimizing an external inductor and can also reduce the overall power system footprint. One power module family that captures all of these critical design elements is the current multiplier which is now powering some of the most advanced artificial intelligence (AI) processors used in high- performance computing applications. Vicor VTMs and MCMs are capable of delivering up to 1000 A, while directly converting 48 V to sub-1 V levels. The integrated planar magnetics in these devices have been optimized over 12 years and now achieve current density levels of 2A/mm? with even further advances planned. Compatibility with high-volume PCB assembly techniques Surface-mount reflow soldering is used by all of the high-volume contract manufacturers (CMs) around the world. The new SM-ChiP™ is a plated, overmolded package intended for surface- mount attachment to a printed circuit board and is compatible with CM manufacturing techniques and equipment. The electrical and thermal connections of the package are formed through soldered connections to plated castellation terminal features along the perimeter of the module and continuous plated surfaces of the main package body. Module production using high-volume automated manufacturing techniques ChiPs are made and cut from a standard- Figure 2: VI Chip and ChiP packaging was necessary to fully realize the breakthrough advances of the new Factorized Power Architecture and continual advances in topologies, control systems, components and materials