Industry Article

DC-DC Switching Regulators Zero In on Automotive and Industrial Designs

While their issues and challenges are distinct, both automotive and industrial systems rely on DC-DC switching regulator technology. Learn how to navigate these issues and make smart engineering choices.

For both automotive and industrial engineers alike, DC-DC switching regulators rank high in importance for their system designs. In automotive (Figure 1), they are used in everything from vehicle navigation to headlights. In industrial products, these devices can be found in robotics, machinery, and PLCs (programmable logic controllers).

In today's fast moving electronics world, both of these applications are evolving. To keep pace, DC-DC switching regulator technology for them must evolve as well.


From infotainment in vehicles to assembly robots in manufacturing, DC-DC switching regulators are indispensable.

Figure 1. From infotainment in vehicles to assembly robots in manufacturing, DC-DC switching regulators are indispensable. Image provided courtesy of Pixabay


To develop cutting-edge products, engineers need access to switching regulator solutions that are evolving with the products they support. In this article, we’ll cover what these solutions could look like for both applications.


DC-DC Switching Regulators for the Automotive Industry

To begin with, let’s dive into the different requirements of DC-DC switching regulators in automotive applications. These include reliability, miniaturization, thermal regulation, electromagnetic Interference (EMI), and development support.



Reliability is always critical in automotive designs. DC-DC converters must maintain consistent, stable operation during fluctuations in voltage, such as those shown in Figure 2. One particular specification that engineers can include in their designs is a DC-DC converter that has a small overshoot that more effectively protects components against sudden battery voltage fluctuations, such as solutions on the market with an overshoot that is 1/10th of the industry standard—600 mV compared to 50 mV for example.


An example of how automotive converters can be engineered to support high reliability.

Figure 2. An example of how automotive converters can be engineered to support high reliability. Image provided courtesy of ROHM



Miniaturization is a key feature, and it means not just reducing the physical footprint but also providing more capabilities on a single chip along with a shorter BOM (bill of materials). For example, DC-DC switching regulators are already available that provide single stage buck regulation that eliminates the need for a secondary DC-DC converter.



Efficiency will remain a major concern for DC-DC regulators for both traditionally powered vehicles and electric vehicles (EVs), especially as the automotive market moves toward sustainable energy sources. For example, conventional primary DC-DC switching regulators for the automotive industry aim for a quiescent current of 2.2 mA, while some solutions have achieved a quiescent current consumption of 25 µA and in the future the norm will likely be 4 µA.

Engineers will also be looking for component manufacturers that can promise them a reliable, stable source of regulators and any supporting hardware.


Thermal Regulation 

Better thermal regulation remains important in the automotive industry for various reasons, including that heat generation decreases the life of DC-DC switching regulators. What makes addressing this issue more challenging are miniaturization and the aggressive operating environment of vehicles.

To better address thermal issues, engineers will look for solutions that eliminate bulky, costly heat sinks and provide easy-to-use, effective thermal simulators for engineers to use in their designs. Approaches to alleviating heat generation issues include maximizing the copper area used for the footprint on the PCB and positioning components on the PCB to promote heat dissipation.


Product Line Choices 

Evolving product lineups will also be critical in the future. The design specifications and constraints for automotive applications will become more stringent as technology advances and ADAS (advanced driver assistance systems) and self-driving technology continues to evolve. 

The widespread adoption of more automated vehicles will invariably lead to enhanced safety and functionality concerns. Meanwhile an increasing focus on sustainable energy will cause energy efficiency requirements to go higher. Engineers will need continuously updated product lines of DC-DC switching regulators that meet the new design specifications, constraints, and automotive standards.


Electromagnetic Interference

EMI is already a major issue for automotive electronics, including DC-DC switching regulators. Interference can cause electronics to behave in unexpected ways, potentially putting in danger not only those on a vehicle but those around them as well. 

Interference issues are becoming more challenging for three reasons:

  1. An increase in the number of regulators used
  2. The demand for miniaturization
  3. Ever higher switching frequencies.

With all that in mind, designs must demonstrate compliance with the CISPR 25 Class 5, and engineers will need support and assistance in doing so. These are complex requirements that vary according to the purpose of components, and products require extensive testing and documentation to prove that a product is indeed compliant.


Development Support 

Support for engineers developing power solutions is also important as design specifications and regulator technology continues to change. For example, the reference board shown below in Figure 3 covers infotainment and ADAS and has been tested for electrical characteristics, thermal behavior, and electromagnetic compatibility (EMC).

Reference and evaluation boards such as this help engineers become familiar the configuration and implementation requirements of specific DC-DC switching regulator solutions, as well as how to test and evaluate critical specifications.

A reference design that uses the ROHM BD9P series as the primary power supply and the BD9S series as the secondary.

Figure 3. A reference design that uses the ROHM BD9P series as the primary power supply and the BD9S series as the secondary. Image provided courtesy of ROHM


ADAS is important as the automotive industry continues to move towards smarter, more automated vehicles. Meanwhile, infotainment combines information and entertainment, which end-users are expecting to see in newer vehicles. Both of these serve as excellent test applications for evaluation boards, allowing engineers to determine the feasibility and performance of primary and secondary switching regulators.


Serving the Requirements of Industrial Applications

Like in automotive, In the industrial system design world DC-DC switching regulators play a major role. Indeed, issues like efficiency and miniaturization are equally important, but from a different context. Meanwhile, EMC and thermal design are critical concerns in industrial designs when it comes to DC-DC switching regulators.


High Efficiency 

Higher efficiency will remain a top priority for industrial applications. Unlike automotive uses, however, industrial applications depend more and more on rechargeable batteries that need to run longer on a single charge. For example, DC-DC switching regulators are often used to power the BMS (battery management system) and receive DC current from the battery cells. 

High efficiency regulators lead to reduced operating costs, which is especially true for the future of automation, as illustrated in Figure 4. To achieve high efficiency, engineers should look for regulators that have ultra low quiescent current at 20μA maximum as well as efficiency between 80% and 85%.



Miniaturization is also key and impacts the overall size of automated products, such as drones and robotics, whose size can limit where they can be used. Engineers will be looking for the most compact, lightweight solutions possible.

Furthermore, miniaturization reduces weight, supporting more efficient performance and longer runs on a single battery charge. On the other hand, miniaturization leads to potential issues with excessive heat generation and efficiency. 

Figure 4. The future of industrial and warehouse automotive will depend heavily on rechargeable, lightweight designs. Image provided courtesy of Shutterstock


Improved Thermal Performance 

Again, as seen with the automotive industry, DC-DC switching regulators must exhibit better thermal design. As illustrated in Figure 5, heat generation and dissipation is always an issue for DC-DC switching regulators because heat and high temperatures can affect the performance of electrical components and reduce their useful life. 

Engineers know that better thermal design does not just mean thermal dissipation but also requires the elimination of bulky, expensive heat sinks through choosing regulators with chip packaging designs that minimize heat generation, along with optimizing the PCB layout for implementation of the regulators. And keep in mind that bulky heat sinks contribute to the size and weight of the regulators, making better thermal design also key to further miniaturization. 


Changes in the design and implementation of DC-DC switching regulators can dramatically impact their thermal performance.

Figure 5. Changes in the design and implementation of DC-DC switching regulators can dramatically impact their thermal performance. Image provided courtesy of ROHM


Engineers responsible for developing cutting-edge industrial products will be looking for a stable source of regulators. And this goes behind the sources for electronic components: manufacturers will need to demonstrate that they have reliable access to the raw materials that go into manufacturing chips through revealing the procurement guidelines they follow.


EMC Performance 

Enhanced EMC performance is a must as EMC standards become stricter as electromagnetic interference continues to become more prevalent in industrial settings. In part, this is due to the increased use of electronics combined with the wireless transfer of massive amounts of data that are hallmarks of the switch to digital manufacturing, Industry 4.0, and IIoT (Industrial Internet of Things). As a result, engineers will need DC-DC switching regulators that comply with international EMC/EMI standards and provide effective filtering options.

In the future, industrial product development teams will be looking for sources of DC-DC switching regulators that offer a flexible approach to manufacturing where manufacturers must be set up to respond quickly to evolving industrial requirements, such as chip design or modified EMC/EMI standards. This can include everything from the type of raw material used to the final chip packaging.

For design aspects such as thermal and EMC, better simulation tools must be provided to engineers. In fact, manufacturers that can provide simulation tools and advice for meeting design specifications and EMC compliance will be vital. Providing this service will shorten the time to market and free up design teams to focus on more critical parts of designs.


ROHM DC-DC Switching Regulator Solutions

In line with the trends discussed in this article, ROHM has been analyzing what DC-DC switching regulators of the future should and will look like and are meeting those needs today. This includes efficiency, miniaturization, thermal design, EMC performance, simulation tools, flexible manufacturing, and a stable source of regulators. 

For automotive applications, ROHM is expanding the DC-DC switching regulators available in the ROHM BD9P (primary) and BD9S (secondary regulators) family. These high-efficiency switching regulators include ROHM’s proprietary Nano Pulse Control, supporting ultra-fast pulse control, stable performance, and miniaturization. They also include ROHM’s QuiCurr (Quick Current) technology that achieves a high-speed load response.

ROHM has also enhanced its DC-DC switching regulators for industrial applications. This includes improving their lineup for 60 V , 48 V, and 24 V power rails available in the ROHM BD9x family, of which the BD9S line is a subset. For industrial applications, the BD9x family includes:

  • 3.3 V / 5 V input buck converters
  • 12 V input buck converters
  • 24 V input buck converters
  • Wide input Voltage 24 V / 48 V / 60 V buck converters
  • 56 V (max.) input buck controllers
  • Isolated flyback converters

All ROHM switching regulators are in compliance with applicable EMC/EMI standards and ROHM provides support for verifying that specific implementations meet application specific standards.

In addition, the ROHM Solution Simulator supports engineers through the design and testing phases, along with design data, PCB libraries, and simulation for SPICE circuit design and thermal simulations to optimize heat dissipation.


A Multi-pronged Challenge

The challenge of meeting future DC-DC switching regulator needs is a multi-pronged beast. Suppliers must support miniaturization, ever-improving efficiency, better thermal design, enhanced EMC/EMI performance, and powerful simulation tools. ROHM is meeting those future requirements now.


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