ROHM Targets Smart Rings with Ultra-Compact NFC Wireless Power Chipset

Why It Matters

By enabling efficient, low‑profile charging, the chipset removes a key barrier to mainstream adoption of truly miniature wearables, opening new revenue streams for device makers. It also accelerates time‑to‑market by cutting component count and design complexity.

Key Takeaways

• NFC charging enables sub‑centimeter antennas for smart rings
• 250 mW power transfer with up to 45 % efficiency
• Integrated firmware removes need for external MCU, simplifying design
• ROHM’s chipset already in mass‑production for SOXAI Ring 2
• Smaller footprint reduces board size, aiding compact wearable form factors

Pulse Analysis

The wearable market is rapidly shifting from bulkier fitness bands to sub‑millimeter devices that sit on a finger or wrist. Traditional Qi wireless charging, while ubiquitous in smartphones, relies on coils that are too large for these form factors, forcing manufacturers to resort to inconvenient wired solutions. NFC‑based power delivery, operating at 13.56 MHz, offers a compelling alternative because its antenna can be printed or etched in a fraction of the space, preserving the sleek aesthetics that consumers demand.

ROHM’s ML7670 receiver and ML7671 transmitter pair exemplify this trend by integrating power management, switching MOSFETs and firmware into a single die. The 250 mW power ceiling, coupled with a reported 45 % transfer efficiency, meets the modest energy needs of health‑monitoring sensors, Bluetooth radios, and low‑power processors typical of smart rings. By embedding the control firmware, the solution eliminates a separate microcontroller, reducing bill‑of‑materials cost and simplifying firmware development cycles. Engineers can now prototype with reference boards that fit on a fingertip, accelerating design validation and shortening product timelines.

Industry analysts view this development as a catalyst for broader adoption of NFC‑enabled wearables beyond niche health gadgets. The ability to deliver both data and power over the same link paves the way for seamless user experiences, such as tap‑to‑charge and instant device pairing. As more OEMs adopt the technology, we can expect a competitive push toward higher efficiencies and greater power budgets, potentially expanding NFC charging into earbuds, smart glasses, and even medical implants. ROHM’s early market entry positions it as a key supplier in the emerging ecosystem of ultra‑compact, battery‑light wearables.