3D Power Packaging for Green Energy

Power semiconductors are vital components of all electronic systems, from smartphones to automobiles, and improvements in power semiconductors accelerate the transition toward a green economy.

Newer, more sophisticated DC/DC converter designs are helping reduce energy consumption through increased efficiency. The best DC/DC converters have conversion efficiencies greater than 95%, spurred by design innovations and access to new materials such as silicon carbide (SiC) and gallium nitride (GaN). Green technology product designers have taken note of the fact that the number of power semiconductors used in the global renewable energy market, for example, is expected to grow at a compound annual growth rate (CAGR) of 8–10% between now and 2027.

Increased efficiency is one piece of the puzzle; improved power density is another because it allows designers to fit more power into the same volume. Therefore, a new application can provide more functionality in the same amount of space as its predecessor or equivalent functionality in a smaller space. This is particularly important considering the fact that many green applications replace a mechanical devices with their electronic counterparts. For example, an electric vehicle (EV) replaces belt-driven mechanical HVAC units and power steering pumps with electronic versions that must still fit into the limited space under the hood. And, of course, reduced size translates into reduced weight. It may not seem like much for a single device, but all those small weight reductions increase the vehicle’s range.

What is three-dimensional power packaging (3DPP^®)?

Maximizing system performance includes maximizing the performance of the power subsystem, which includes all power supplies, power conversion devices, filters, protection devices, and their interconnects, such as connectors, wires, cables, circuit board traces, etc.

The metrics to be considered include size, weight, and power (SwaP), or SwaP-C, when the cost is included. Three-dimensional power packaging (3DPP) is an advanced packaging technique that allows power conversion designers to combine many state-of-the-art technologies into highly dense, integrated devices while optimizing SWaP-C. 3DPP employs cutting-edge assembly processes to achieve the maximum power density with a minimal footprint. When applied to surface-mount DC/DC converters, 3DPP enables solutions that combine best-in-class performance with maximum power density and minimal footprints. This results in power products that are significantly smaller than other power conversion modules and still highly efficient without the costly footprint.

3DPP technology eliminates the need for an internal printed circuit board (PCB) by mounting the required components directly to a lead frame, reducing the amount of space required within the module. This size reduction allows engineers and designers to have more streamlined PCB profiles with integrated power conversion without needing a costly, custom converter design.

Of course, numerous manufacturing advances were needed on the road to 3DPP technology. Among them were the ability to embed both passive and active devices; the incorporation of flip-chip technology; and techniques to minimize inductive and capacitive parasitics caused by internal package interconnects such as pins, bumps, and pads. The development of planar magnetics, such as inductors and transformers, was another key step because it allowed for the construction of a cleaner, tightly controlled, repeatable, and robust magnetic component in a compact form factor.

The RPX-1.0 DC/DC converter: a complete DC/DC buck regulator in a tiny package

3DPP-technology-enabled devices are available in several package types, including land grid array (LGA), gull-wing, quad-flat no-leads (QFN), blocks-and-pillars, and solder balls, which can make all the difference in a space-constrained application.

RECOM’s RPX-1.0 showcases the advantages of 3DPP packaging technology. It is a non-isolated buck regulator power module complete with an integrated inductor in a thermally enhanced QFN package. The RPX-1.0 measures only 3mm × 5mm × 1.6mm, making it comparable in size to an integrated circuit (IC). The input range is from 4 to 36VDC, allowing 5V, 12V, or 24V supply voltages to be used. The output voltage can be set with two resistors ranging from 0.8VDC to 30VDC. The output current is up to 1A and is fully protected against continuous short circuits, output overcurrent, or over-temperature faults.

The RECOM RPMB/RPMH series is a 30W family of non-isolated power modules in a thermally enhanced 25-pad LGA package measuring 11.7mm × 12.19mm × 3.75mm high. This power density is achieved with 3DPP technology, a multilayer internal PCB that utilizes plugged and blind vias for good thermal conductivity and efficient use of the available space. Six-sided metallic shielding ensures low EMI.

3DPP packaging can lend itself to isolated topologies, too. The RxxCTxxS is a family of cost effective, low-profile, 500mW SMD isolated DC/DC single-output converters ideal for applications such as PV-powered sensor installations, medical applications, and communication nodes that require robust isolation. The R05CT05S is a single solution with a 5V input and a user-definable single, regulated 3.3V or 5V output. There is no minimum load requirement. Standard isolation is 5kVAC per minute with a 2MOPP rating for medical applications.

Conclusion

Many green energy applications require DC/DC converters with efficient operation in a small form factor. RECOM’s 3DPP technology is being adopted in numerous isolated and non-isolated converters that combine high power density with extremely small sizes.