【Adoption Example】SOXAI Inc. - A Japan-Origin Smart Ring for Sleep Management

ROHM’s wireless power charging ICs contribute to the realization of wearable health devices

Adoption Background

SOXAI Inc. (pronounced “SOK-sai”), guided by its vision of “Making healthcare a lifestyle,” proposes everyday health management through its sleep-tracking smart ring, SOXAI RING. The company places a strong emphasis on wearability and design, developing products that integrate seamlessly into daily life. Since launching its first model in 2022, SOXAI has utilized high-frequency wireless power transfer in the 13.56 MHz band by using ROHM’s ML7630/31 NFC wireless power ICs. This approach enables stable power delivery even in confined spaces, making it a core technology for smart ring development.
For the development of the new model, SOXAI RING 2, the goal was to create the world's thinnest, most compact design, which demanded even greater miniaturization and power efficiency than the previous generation. Given the strict constraints of the ring form factor, additional optimization of the wireless charging system was essential. After comprehensively evaluating size, power consumption, and charging efficiency, SOXAI selected ROHM’s ML7670/71 NFC wireless power transfer ICs.
These ICs not only reduce the size of the receiver component but also boost maximum power transfer efficiency from approximately 30% to 45%. By implementing a Class E amplifier architecture on the transmitter side, power loss is minimized, ensuring high-efficiency wireless charging.
Despite the need for a rapid development cycle, the proven performance of the previous model—together with validation using evaluation boards and close collaboration with SOXAI—allowed the team to complete functional evaluation in just four months and reach the mass production prototyping within six months, significantly accelerating the overall development timeline.

＜Customer Feedback＞ 

SOXAI Development Team

Achieving practical power delivery within a ring’s compact form factor required careful attention to both efficiency and stability. ROHM’s comprehensive support, from IC characteristics to antenna design, gave us the confidence to move forward at every stage of development. The result is a device that delivers up to 14 days of continuous operation with just 60 to 120 minutes of charging, meeting the performance standards essential for everyday wear.

Adopted Products

• Wireless Power Receiver IC [ML7670]
• Wireless Power Transmitter IC [ML7671]

Related Pages

• Wireless Power Charging ICs

About SOXAI

SOXAI Inc.

Website (Japanese) : https://soxai.co.jp/

Product Page (Japanese) :
https://soxai.co.jp/pages/soxai-ring-2-lp-b01

SOXAI Inc. is a health-tech company founded in 2021 with the mission of “Contributing to the improvement of QoL (Quality of Life ) for people worldwide through technology.” By applying vital-sensing technology into all aspects of daily life, the company is working toward a future where people can enhance their health naturally and seamlessly.