Solving Challenges Through the Fusion of Analog and Digital, New Options for Power Supply Control ICs in the Low to Medium Power Range-LogiCoA™ Power Supply Solution

New Options for Power Supply Control ICs in the Low to Medium Power Range

10/18/2024

Power control ICs are essential for the operation of all electronic products and equipment.
Selecting the right power control IC and implementing the appropriate design are crucial for ensuring that applications operate smoothly and efficiently. However, some engineers may assume that all power control ICs are pretty much the same. In this article, we will explore the fundamentals of power supply control ICs, revealing aspects you might not be aware of along with ROHM’s current efforts in pioneering new power technologies that will revolutionize the power supply control IC industry.

1. Analog vs Digital Control

Currently, there are two main methods used for power control ICs.
Those that utilize analog controllers for analog control and those that employ MCUs or similar devices for digital control.

As you may know, analog involves capturing data as smooth, continuous variations. In contrast, digital operates in a world of 0s and 1s, where continuous quantities are divided into steps and expressed numerically. Each method has its advantages and disadvantages, with power control ICs selected based on the specific requirements of each application.

2. Pros and Cons of Each Approach

While both analog and digital control power supply ICs are available, their characteristics differ significantly. For example, analog control does not require costly CPUs or DSPs, resulting in lower costs and reduced power consumption compared to digital control. On the other hand, digital control enables precise adjustments tailored to the application, offering capabilities not possible with analog control, such as calibration and log acquisition.

3. Choosing Between Analog and Digital Control

Currently, the decision to use analog or digital power control ICs depends on the power domain of the electronic device or electrical equipment.

Typically, analog control power ICs are employed in low to medium power applications up to 1kW, such as smartphones, PCs, tablets, robots, FA equipment, and manufacturing devices, while digital control power supply ICs are utilized in electrical equipment above 1kW, including solar power generation systems and EV chargers. This is due to the challenges analog control faces in handling the significant fluctuations in output power found in high-power applications.

However, many engineers engaged in the development of industrial equipment may question the distinction between the two.

4. Is it Acceptable to Continue Using Analog Control in the Low to Medium Power Range?

Analog control power supply ICs are currently the preferred choice for medium power industrial equipment. However, they are optimized for a single application, meaning the power circuit cannot be reused in its current form. When requirements such as the supply voltage and output power change, individual adjustments to the power circuit must be made, creating a barrier when developing derivative products that places a heavy burden on designers.

What’s more, analog control does not allow for fine adjustment of the output according to the power used, leading to poor power conversion efficiency (AC-DC). And when developing power supplies, component characteristics must be taken into account. Particularly for inductors and power devices that could be damaged if their ratings are exceeded, designs must ensure sufficient margins, further increasing the burden on the designer.

Depending on the application, employing analog control power supply ICs for industrial equipment in the low to medium power range can be time-consuming and inefficient for engineers. So why are analog power supply control ICs still utilized in these applications? The primary reasons are power consumption and cost.

Despite the growing demand for digital-controlled power supplies in the low to medium power range for industrial equipment, challenges related to power consumption and cost hinder the adoption of digital control in these power systems.

Additionally, ROHM believes that the differing design philosophies between analog and digital engineers play a significant role in the slow adoption of digital control technologies in the small to medium power range.

5. Digital Control for Low to Medium Power Supplies

As the electrification and automation of industrial equipment accelerates, shouldn’t power control ICs in the small to medium power range evolve as well? Isn't it feasible to develop a power supply control IC that combines the advantages of both analog and digital technologies, rather than having to choose between the two?

To address the challenges of power supply control in the small to medium power range, ROHM developed the LogiCoA™ power supply solution, the industry's first ‘analog-digital hybrid control’ type using LogiCoA™ MCUs.

LogiCoA™ Brand

LogiCoA™ embodies a design philosophy that fuses digital elements to maximize the performance of analog circuits - an area where ROHM excels. By integrating the strengths of analog circuitry with those of digital control, it is possible to fully realize the potential of circuit topologies, contributing to more efficient power utilization.

*LogiCoA™ is a trademark or registered trademark of ROHM Co., Ltd.

LogiCoA™ Power Supply Solution

A new power solution that achieves exceptional functionality while reducing cost and power consumption, the LogiCoA™ power supply combines 3 elements: a power topology, power control OS, and LogiCoA™ MCU.

LogiCoA™ Power Supply Solution Features

Along with the LogiCoA MCU – a key feature of this new power solution – all necessary analog and digital circuits required for power supply control are integrated into a single package. This makes it possible to achieve the same functionality as digitally controlled power supplies while maintaining the lower power consumption and cost levels of analog power solutions.

In addition to power consumption and cost benefits, the solution incorporates a low-cost low-speed CPU with a 3ch analog comparator and DA converter for digital parameter control. This enables easy adjustment of the output power and other parameters by simply changing them on a PC, dramatically reducing the burden on engineers.

In short, the LogiCoA™ power solution represents a groundbreaking innovation that merges the advanced power control capabilities of digital technology with the cost-effectiveness of analog controllers.

6. New Possibilities in the Realm of Analog Control

The LogiCoA™ power solution is set to transform power control ICs that until now have only been available in analog or digital options. While it may seem a bit exaggerated, the LogiCoA™ power solution has the potential and appeal to bring about significant advancements.

① Operation logs can be saved

For instance, in the area of analog control, it has been difficult to analyze customer complaints or failures due to the inability to determine the state at the time of an anomaly. However, with the LogiCoA™ power supply solution, log data such as input voltage, output voltage/current, and temperature can be stored in Data Flash, allowing for the analysis of the root cause of anomalies from the operation logs. A command interface for reading logs from the MCU is also provided.

② Calibration is performed during outgoing inspection

The built-in calibration function not found in low-performance analog control power ICs eliminates the need for margin design to account for component variations, streamlining the design process.

The calibration function allows for precise setting of overcurrent protection thresholds. Eliminating saturation margins required for choke coils enables the use of power devices with lower current ratings, supporting smaller inductors and power devices to achieve greater miniaturization with lower costs.

③ Simplifies derivative product development, custom development, and inventory management

The LogiCoA™ power supply solution makes it possible to modify specifications such the output voltage by adjusting parameters, allowing a single MCU and circuit to flexibly accommodate various needs, such as derivative product development, custom development, and series expansion. At the same time, control functions can be added by simply changing the software without requiring additional circuits, creating an environment conducive to developing more derivative products.

Furthermore, the extensive range of supported power supply topologies removes the necessity of stocking power control ICs for each topology, greatly simplifying inventory management. Incidentally, ROHM plans to release reference designs (circuits) for various power topologies in the future.

④ Simultaneous control of two converters with one MCU is possible

The real-time operating system RMOS, designed for state transition control suitable for power management, coupled with sample programs tailored to the two different topologies enables simultaneous control of two converters using a single MCU. This contributes to reducing both mounting area and costs.

⑤ Comprehensive support system facilitates the start of customer evaluations

ROHM’s LogiCoA™ power supply solution is set to revolutionize power control ICs in the small to medium power range. However, introducing new technologies often brings a degree of uncertainty. Specifically, engineers who have primarily worked in the analog field may be resistant to adopting digital control.

To alleviate the concerns and burdens of engineers, ROHM provides support for the LogiCoA™ power solution through the community on our engineer-focused technical site ‘Engineer Social Hub™’ (Japanese only). As many engineers are already progressing with their evaluations, we encourage you to take advantage of this solution.

*Engineer Social Hub™ is a trademark or registered trademark of ROHM Co., Ltd.

And for those exploring new power designs, we plan on releasing an AC-DC (current-critical PFC + pseudo-resonant flyback) evaluation kit. We invite you to experience the LogiCoA™ power solution that offers adjustment functions and setting changes via communication GUI – features not possible with analog control.

7. Conclusion

The LogiCoA™ power solution excels at embedded processing across a diverse array of applications, including industrial equipment, automotive systems, industrial IoT, edge computing, and autonomous vehicles.