Article co-authored by Texas Instruments’ Rahil Ajani
A power module is a switching regulator that integrates high- and low-side gate drivers, metal-oxide semiconductor field-effect transistors (MOSFETs), an inductor or transformer, and several passive components into one package. With integrated components and optimized performance, power modules can help you achieve high power density and low electromagnetic interference (EMI), while freeing up valuable board space and accelerating time to market.
Despite these benefits, designers have concerns about power module-based solutions. Some view them as expensive or only for those who are incapable of completing their own designs. So, let’s address these perceptions by debunking some common misconceptions about power modules.
Misconception 1
Power Modules Don’t Save Much Design Time
Power modules can be very helpful when you have a quick turnaround time. Today’s power modules take the performance features found in next-generation DC-DC regulators and integrate them with passives that are hand-selected and validated for that regulator. This prevents you from having to worry about inventory issues when sourcing the correct inductor or determining the best layout to mitigate voltage ripple. Additionally, today’s power modules require very few external components, turning a problem that could have taken multiple days to solve into a task that takes only a few hours.
Misconception 2
Power Modules Are Too Big And Won’t Save Space In Your Design
Today’s power modules save board space by incorporating the integrated passives as close to the converter integrated circuit (IC) as physically possible—closer than what is possible when designing the same system discreetly. As shown in Figure 1, in just the last four years, Texas Instruments (TI) has been able to shrink the footprint of some of its 36 V module families. For example, in the case of the TPSM33625, mounting the buck converter die directly to the package leadframe saved 80% more board space than the previous generation.
Figure 1. TI power module package sizes have shrunk in the last four years without sacrificing performance or efficiency.
Misconception 3
Power Modules Are Not Cost-Effective
The price of semiconductors as a whole has decreased over the years thanks to advancements in manufacturing and testing technology. Take these advancements and add high-volume passive pricing only available to semiconductor manufacturers, and you get integrated power module solutions that are comparable—if not cheaper—than a discrete solution.
Misconception 4
Power Modules Are Not Optimized For Efficiency, Thermal Or Noise Performance
A common misconception many designers have is that the preselected integrated inductor trades good performance for ease of use. Conversely, power modules are designed to provide a high-efficiency solution with great thermal control, in addition to the advantage of integration. Modules also often use an inductor with shielding to lower electromagnetic interference. As shown in Figure 2, TI’s TPSM82866A can reach up to 96% efficiency, with thermal performance that enables operation in ambient temperatures as high as 125°C.
Figure 2. Thermal performance of the TPSM82866A evaluation module; VIN = 5 V, VOUT = 1.2 V, IOUT = 6 A
Discrete solutions often trip up even the best designers given the multitude of contributing factors on performance. For example, efficiency relies on switching transistors, thermal dissipation and heuristic external component selection. Power modules are designed with these factors already in mind to deliver the easiest solution possible while maintaining or exceeding the performance of a discrete solution.
Misconception 5
Power Modules Use Last Year’s Technology And Packaging
IC manufacturers are pushing boundaries in packaging, component placement and process technology to streamline electronic design and production.
The performance features traditionally associated with converters are also available in modules. TI develops its modules in tandem with its converters so that they share the latest technological advancements. One such advancement involves using the newest MagPack packaging technology to upgrade the TPSM828303 for better performance and cost savings. To learn more about MagcPack technology, read TI’s technical article, “4 benefits of our new MagPack technology for power modules that can help you pack more power in less space.”
Misconception 6
Power Modules Are Not Designed For Harsh Applications
If a power supply needs to operate in a harsh environment, you should ensure that extreme ambient temperatures will not cause a malfunction. You can do this by using a module solution with an extended temperature range.
Outside of harsh temperatures, interference from a power supply can result in unwanted noise or distortion in medical imaging equipment, requiring a solution that is compliant with the standards dictated by Comité International Spécial des Perturbations Radioélectriques, as shown in Figure 3.
Fortunately, power modules come pre-validated to fulfill these requirements, offering a plug-and-play solution.
Figure 3. Cart-based ultrasound scanners require low EMI to produce clean images.
Power-supply designs are getting complicated, and requirements are becoming more stringent. Every day, engineers are moving toward using power modules given the benefits they provide in terms of size, efficiency and performance features, proving that they’re not just a trend but here to stay.
All images used courtesy of Texas Instruments
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