Stories of Manufacturing#10
Engineering at the billionth scale
Nano Power Supply Technology
Creating New Core Technologies for Power ICs
In the mid-2010s--around a decade ago--ROHM confronted a fundamental question within the field of power solutions, a domain that forms the backbone of semiconductor technology: ‘Is it enough to simply meet today's needs?' In a rapidly evolving market, what was needed was power technology designed with a forward-looking perspective.
From this commitment emerged the Advanced Power Development Project.
The mission of this project was unmistakable: to push the boundaries of energy efficiency and miniaturization. Rather than optimizing performance on an application-by-application basis, the objective was to innovate the core technologies of power supply ICs. Leveraging ROHM’s vertically integrated production system, the team expanded beyond circuit and layout design to include process technology as well.
This initiative carried a strong determination--not simply to build the 'next generation', but to create power technologies that will shape the future.
Looking back, the semiconductor landscape of that period marked a pivotal turning point for power ICs.
The smartphone and tablet markets had matured and approached saturation. At the same time, the rapid adoption of hybrid vehicles, EVs, and ADAS intensified the demand for automotive-grade semiconductors that deliver higher voltage capability, enhanced reliability, and improved efficiency.
It was also a period when sensors, wearables, and smart appliances--compact devices connected through networks--began to emerge, and the idea of a ‘connected world,’ or IoT, was becoming mainstream.
Within this rapidly expanding ecosystem, power ICs were faced with an unprecedented diversity of application requirements and technical hurdles.
New demands surfaced one after another, like bamboo shoots after the rain, forcing manufacturers into an era that demanded both accelerated development and heightened design flexibility.
To address these challenges, ROHM's Advanced Power Development Project focused on three fundamental priorities:
● Maximize energy savings and power efficiency
● Support high power operation
● Achieve greater integration while reducing the size/number of peripheral components
The project embarked with a clear vision, but the early phases were far from smooth. The path forward consisted of continuous trial, error, and exploration--an essential process in the pursuit of breakthrough innovation.
Born from a Sense of Urgency
Yamaguchi-san, who was deeply involved in power supply IC development as part of the Advanced Power Supply Development Project, recalls the situation ten years ago.
'At the time, we were exploring new ways to control switching using extremely narrow pulses.'
General Manager
Industrial and Consumer Systems Marketing Dept.
Yamaguchi:
'Looking back now, I’m truly grateful for those words--but at the time, I was honestly frustrated. Competitors were already achieving pulse widths of around 30ns, while ROHM was still at 120ns. We were clearly behind, and the customer was right. That desire to catch up and surpass expectations became the driving force behind everything that followed.'
The conventional pulse control method, which detected IC operating conditions through current, faced two major obstacles: 'noise' and 'circuit delay'.
After months of endless trial and error with no end in sight, Yamaguchi-san finally found a potential path forward.
The turning point came through the support of Tateishi-san, a top engineer in the company who played a leading role in the Advanced Power Development Project.
The Birth of Nano Pulse Control™
Yamaguchi:
"One day, I decided to share the challenges and possibilities with Mr. Tateishi, one of ROHM's top engineers.
We were both searching for the next move when, just before leaving work one evening, a new idea came to me--a shift in perspective that made me think, 'This could actually work.'
Excited, I went straight to Tateishi-san.
He smiled and said, 'I was thinking exactly the same thing.'"
A photograph of Yamaguchi-san and Tateishi-san during the early days of development.
What began as casual conversations in front of the design team often escalated into a highly focused technical discussions.
Tateishi-san brought decades of experience in LSI development, while Yamaguchi-san contributed with the drive and determination of an engineer.
When their vectors aligned, it was like spontaneous combustion--a flash of insight that crystallized into tangible technology. This was, in essence, the origin of Nano Pulse Control™.
Although this synergy might seem like a fortunate coincidence, behind it was ROHM’s unique culture--where colleagues inspire each other through open dialogue.
Tateishi:
"Innovation isn't something even a 'superhero' can accomplish alone.
It starts with someone who is willing to think deeply from every angle, supported by colleagues with diverse skills. Through repeated dialogue, a sudden spark occurs--some call it a chemical reaction. One reason ROHM's analog power technologies continue to follow a unique path is because of this culture of thinkers and collaborators who help ideas take root."
Director and Senior Executive Officer
The concept born from their discussion rapidly evolved into a novel circuit architecture that successfully overcame multiple challenges such as circuit delay, noise caused by parasitic inductance, and even the effects of ringing.
In 2017, the technology debuted as a commercial product featuring the world’s smallest ON-time of just 9ns--a remarkable achievement.
This innovation that converts high-voltage input to low-voltage output with a single chip has made a significant impact both in Japan and worldwide.
A Core Technology for Switching Control
In 2017, ROHM introduced its first DC-DC converter equipped with Nano Pulse Control™, initially targeting the growing market for 48V mild hybrid vehicles in Europe. However, as the mild hybrid segment expanded more slowly than anticipated, the strategy shifted to repurpose this technology as a core switching control solution for conventional 12V systems.
Scenes from the semiannual ‘New Technology/New Product Presentation.'
Through active exchanges between engineering and sales teams, new insights, new strategies and products consistently emerged.
Driven by the belief that 'continuous technical refinement' must be paired with 'broad horizontal deployment,' ROHM proactively highlighted the performance and potential of this innovation at internal companywide events such as the 'New Technology/New Product Presentations'. As a result, Nano Pulse Control™ has spread beyond automotive systems into a wide range of markets. Improvements in device structures and advancements in package technology further enhance operating frequency and efficiency. Today, it has become the 'core technology for switching control', integrated into nearly all ROHM power ICs (switching regulators).
In addition, because Nano Pulse Control™ maximizes the intrinsic high-speed switching capability of GaN devices, deployment into controller ICs for GaN devices is already underway.
By leveraging GaN, ROHM has succeeded in reducing control pulse width to as little as 2ns. Through ongoing refinement of device structures and optimization of packaging technologies, ROHM will continue to unlock new possibilities--enabling compatibility with an even broader range of power conversion topologies.
Nano Energy™ Technology Redefines Ultra-Low Power Consumption
Around the same period that Nano Pulse Control™ was introduced, another breakthrough technology was developed and brought to market.
While Nano Pulse Control™ is defined by ns (nanoseconds) pulse width control, the next innovation centered on nA (nanoamperes)-level current consumption. This became known as Nano Energy™ technology.
In the mid-2010s, as sensor networks and IoT rapidly expanded, a critical question arose: how can we deliver limited power efficiently, only when needed in the exact amount?
As the industry transitioned into a new era demanding a fundamentally different approach to power delivery, Nano Energy™ emerged as ROHM’s direct answer to this challenge.
Chief Engineer
Industrial and Consumer Systems Marketing Dept.
Tsuruyama:
'Reducing the power consumption of DC-DC converters was a major focus. This is a common challenge for any IC, but as we push for lower power, circuit response speed, including in comparators, inevitably slows down. This trade-off was the biggest technical hurdle.
The question was how to achieve ultra-low power consumption without sacrificing performance.'
One of the explicit development goals was to achieve ten years of continuous operation on a single coin cell battery. Assuming a 100mAh battery, sustaining operation for 87,658 hours requires an effective current draw of 970nA or less--truly nanoampere-level power consumption.
At that time, a competitor had already launched a nano-level DC-DC converter, whereas ROHM's lowest consumption remained around 30uA.
Meeting the 970nA target required reducing the current level to 1/30th, and surpassing the competition meant pushing toward an unprecedented 1/80th.
Despite the magnitude of the challenge, Tsuruyama-san and the development team pressed forward, overcoming each obstacle with persistence and innovation.
From Inspiration to Technology--and Ultimately Breakthrough
Tsuruyama:
'Traditionally, designers try to strike a balance between speed and power consumption within a single comparator.'
'But we took a completely different approach--using two comparators, one dedicated to high-speed response and the other to ultra-low power consumption, switching between them as needed. On top of that, we developed a proprietary technology to automatically compensate for any variations between the two.'
Transforming this unconventional concept into robust technology required multiple strategies. Among them were joint initiatives with the manufacturing division, such as developing bend-resistant structures and establishing a differential reference voltage scheme (known as Enh-Dep at the time). These efforts exemplify the advantages of ROHM’s vertically integrated production system.
In other words, we went beyond circuit design and ventured into component-level innovation, ultimately, achieving a major breakthrough.
The result of this ground-up rethinking of DC-DC converter power savings was Nano Energy™ technology, which rapidly evolved into a switching regulator featuring the world’s lowest current consumption. By tackling one of the most persistent challenges in power IC design, this achievement not only marked a milestone for ROHM but also earned recognition among engineers both inside and outside the company.
Technologies that Connect and Evolve
The elemental technologies established through this development have continued to expand and evolve over the years.
In 2022, the ultra-low power design principles of Nano Energy™ were first applied to reset ICs, addressing strong demand for reliable, energy-efficient voltage monitoring functions in automotive and industrial equipment requiring functional safety.
In addition to meeting requirements such as ① wide operating voltage range and ② high detection accuracy, achieving ③ ultra-low power consumption was also essential to extend battery life in portable devices and reduce dark current in automotive systems.
ROHM leveraged its strengths in analog circuit design to achieve both nanoamp-class power consumption and industry-leading accuracy, earning strong recognition from customers.
In 2024, the evolved Nano Energy™ technology was incorporated into linear op amps featuring the industry’s lowest power consumption.
These op amps, essential for high-precision signal processing in diverse sensing applications, now deliver both exceptional accuracy and ultra-low current consumption to support system-level power savings.
Nano Energy™ is expected to power an even broader range of applications, from extending battery life in electronic shelf labels to enabling longer operating times for smartphones and other rechargeable devices.
Furthermore, the journey that began with applying Nano Energy™ to LDOs, which involved contributions from numerous engineers, led to the creation of Nano Cap™, often referred to as the third Nano technology.
Stable Control with Ultra-Small Capacitors--Nano Cap™
Following innovations centered on nanoseconds (ns) for pulse width and nanoamperes (nA) for current consumption, ROHM's next frontier in power management at the one-billionth-scale focused on capacitance--measured in nanofarads (nF). Capacitance, the ability to temporarily store and release electrical charge, is fundamental to ensuring stable operation in electronic devices.
Around this ultra-small nF domain, ROHM engineers embarked on a new challenge.
Takobe:
"'At the time, the world was facing a global capacitor shortage brought on by the pandemic.'
I was working on Nano Energy™ and other initiatives within the Advanced Power Supply Development Project when Nagata-san from the Product Development Department contacted me.
His message was essentially: 'If we can reduce the number of capacitors, the product value will increase dramatically.'
This comment reminded me of an earlier discussion with Watanabe-san, who was working on switching power supplies.
'He once asked, 'Could switching power supply technology be applied to LDOs?' When those ideas connected, the path toward what would eventually become Nano Cap™ began to take shape. Looking back, that was truly the starting point.'"
Chief Engineer
Power GaN Solutions Development Dept.
Takobe-san, who has been engaged in power IC design since joining the company, recounted how Nano Cap™ development began. Although the supply uncertainty due to the pandemic acted as the catalyst, the need to reduce external capacitors had been growing for years.
Minimizing component count, shrinking PCB footprint, and reducing design complexity are universal requirements that support set miniaturization, lower costs, improved system reliability.
However, reducing capacitors risks compromising circuit stability.
The core innovation behind Nano Cap™ addressed this contradiction directly. By incorporating high-speed feedback via current alongside traditional voltage-based feedback control, ROHM succeeded in suppressing high-frequency voltage fluctuations even with extremely small capacitance.
This achievement overturned the long-standing belief that ‘large capacitors are essential for stable operation,' opening the door to new possibilities in power supply control.
Nano Cap™ directly feeds back changes in current (i.e. instantaneous load response), enabling stable, high-speed operation without relying on capacitors.
Refining Nano Cap™ Technology
Nano Cap™ emerged as a core technology with the potential to revolutionize power supply design. However, turning this breakthrough into a real product required considerable time and effort.
Iwata:
‘We worked on commercialization under Takobe-san's guidance, covering everything from technical details to practical implementation.
It was truly an exceptional technology, and I was determined to bring it to market. But unlocking the true potential of Nano Cap™ proved challenging, leading to many frustrating days.'
General Manager
Power and Standard LSI Marketing Dept.
General Manager
Power LSI Development Dept. 1
As the Product Development Dept. grappled with these hurdles, Inoue-san and Iwata-san, both with extensive LDO design experience--joined the effort. The Product Planning Dept. also stepped in, reworking the product concept from the ground up to maximize the potential of Nano Cap™ technology.
Key development goals at the time included: Characteristics/performance have further improved as of 2025
● Strengthening the product lineup = Achieve 3x the current capability* while maintaining a minimum capacitance of 47nF
● Extending the frequency bandwidth =Improve transient response by 2x*
● Establishing a stable mass production system =Increase tolerance against component variations
Iwata:
'I appealed directly to the company to fully commit to this project. The first step was restructuring--bringing together teams that had previously been spread across departments--into one. (I was surprised by how quickly that change was implemented!)
Even then, technical obstacles continued to appear, and many people became involved.'
He shared this with a modest smile, acknowledging the burden placed on colleagues while celebrating their perseverance. Ultimately, these efforts led to the successful commercialization of the Nano Cap™ LDO series, which received unexpectedly strong response from customers, shining a well-deserved light on the dedication of every team member.
What sets ROHM apart is its vertically integrated production system (IDM) that supports multi-faceted, comprehensive technology development.
Technology that Connects Ideas
Tateishi:
'Even when engineers come from completely different fields, they can immediately recognize when a technology is truly worth pursuing.
More than teamwork alone, one of ROHM's strengths is the way technical capability itself becomes the bridge that connects people’s ideas and aspirations.'
The term Nano refers to a world measured in one-billionth units--an unimaginably small scale.
Yet within this microscopic realm lies human creativity, determination, and passion, where technological evolution gains momentum. Through persistent, time-intensive trial and error, countless subtle improvements accumulate--driving power supply technology forward.
This steady yet powerful progression will continue to be passed on to future generations.
A single spark of insight can one one day change the world, and the story of ROHM's Nano power technologies will continue to unfold.
Yamaguchi:
"'ROHM's power solutions are two generations behind.' Everything began with this single remark from a customer."