www.vicorpower.com 48V-CENTRIC POWER MODULES 9 www.power-mag.com Issue 1 2025 Power Electronics Europe the same power. For OEMs, this consequence of Ohm’s Law can yield superior electrical, mechanical and thermal performance, higher overall system efficiency and significant economic benefits. Important Attributes to Look for in a Power Module A top-level attribute of best-in-class 48Vcentric power modules is high volumetric power density (continuous output power per cubic inch or W/in3), achieved through innovative circuit structures and topologies, as well as state-of-the-art thermal and mechanical packaging. A related distinguishing characteristic of power modules is package thickness, which can be as thin as 7mm in advanced products. Thin packages enable lower thermal resistance, and three-dimensional electroplating (i.e., bottom, top and sides) provides a coplanar thermal conduction interface perfectly suited for heat sinks and coldplates (Figure 3). Due to increasing equipment electrification across broad sectors of the global economy and the rising power demands across numerous end-market equipment types, liquid cooling solutions are increasingly more popular. This trend is synergistic with overmolded, high power density, thin power modules, which are exceptionally thermally adept (i.e., high thermal conductivity as measured in watts per meter per Kelvins). Designers should also consider overmolded 48V-centric power modules with integrated magnetics, as an easier way to present a planar thermal interface of all power dissipative components to heat sinks, heat pipes or coldplates. Power conversion efficiency is a critically important performance parameter. At high output power levels, the power loss heat load is substantial, even when continuous conversion efficiency is relatively high. For example, at 2.4kW (50AOUT at 48VOUT) at 98% efficiency is still 48W of power loss that must be continuously thermally managed. Therefore modules should offer very high DC-DC conversion efficiency across operating temperature to simplify thermal management solutions. integrated magnetics also minimize external circuitry, easing the system design process. For systems requiring industrial grade, military grade or automotive grade, modules are qualified by their manufacturer to rigorous electrical, mechanical and environmental standards, including temperature cycling, humidity exposure and shock/vibration testing, and are automatically production tested (i.e., using ATE) as a complete system to well-specified performance limits. This eliminates the need for the OEM to conduct separate qualification and performance characterization tests. From the OEM perspective, power modules are a single bill of materials (BOM) item (Figure 4). The fact that there are dozens of components within the module is opaque to the end customer. By contrast, a discretely implemented power supply has a multiplicity of components that must be purchased, kitted, assembled, tested and managed (due to potential product obsolescence) over the lifetime of the equipment that utilizes the power supply. The use of a system-level DC-DC converter power module therefore effectively eliminates numerous points of failure, increasing end-product quality. The purchasing effort and inventory management costs of power modules Figure 2: Vicor automotive grade BCM6135, DCM3735 and PRM3735 power modules have set a new standard for power density in the automotive industry. Collectively they solve complex conversion challenges with 800V, 400V, 48V and 12V systems for xEVs power systems. Figure 3: The thermal engineering of modern electronic systems has become a key design consideration. Discrete power designs are typically more complicated arrangements and are more challenging to cool compared to modular solutions that are thinner, more uniform designs. Thin packages enable lower thermal resistance, and three-dimensional electroplating (i.e., bottom, top and sides) provides a coplanar thermal conduction interface perfectly suited for heat sinks and coldplates. Robust and Simplified System Designs Overmolded power modules are also mechanically robust and more thermally adept easing the thermal management design challenge. Modules that offer full DC-DC converter solutions with are significantly lower than discrete component power systems. This allows power systems engineers to leverage their trusted supplier’s cutting-edge materials science, circuit design and conversion topological innovation with little to no learning curve overhead.
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