Wireless Charging for Medical Wearables with Epson PMICs

Efficient Power Delivery in Space-Constrained Designs

Smart and medical wearables are pushing the limits of miniaturisation. From hearing aids and health monitors to fitness patches and smart rings, these devices increasingly rely on wireless charging to reduce mechanical complexity and improve user experience.

However, integrating wireless power into compact, battery-operated systems introduces several design challenges—particularly around charge control, thermal management, and host communication.

Epson’s PMIC range offers a proven solution. Their single-chip PMICs integrate wireless power reception (WPT), smart charging profiles, and battery communication interfaces—making them ideal for sealed, compact medical-grade wearables.

How Epson PMICs Enable Wireless Charging for Medical Wearables

The 5th generation Epson PMIC, currently finalising for release, offers multiple enhancements that support both wireless and contact-based charging. It’s designed to help engineers simplify their power architecture without compromising safety or performance.

Key capabilities:

• Wireless Power Transfer (WPT) up to 20 MHz Compatible with compact and efficient transmitters for wearable-scale energy transfer.

• Integrated charge pump and control Manages current up to 300 mA via contact or WPT, supporting fast charging in tight form factors.

• Battery communication register Enables direct interaction with the application microcontroller for accurate SoC monitoring.

• Customisable charge profiles Maximises battery lifetime and compatibility across chemistries.

• Built-in protection Covers overvoltage, temperature, and fault conditions—critical for skin-contact devices.

• Flash memory for configuration Allows manufacturers to fine-tune system behaviour per device model.

These features streamline system design for engineers developing health-focused wearables where every square millimetre counts.

Summary of Wireless Charging Specs

Feature	Specification
Wireless Charging Frequency	Up to 20 MHz
Max Charging Current	300 mA (contact or wireless)
Integrated Receiver	Single-chip WPT Rx
Power Conversion	High-efficiency charge pump
Battery Interface	Shared register with MCU
Built-in Flash Memory	Yes
Safety Functions	Overvoltage, current, thermal

Based on 5th Generation Epson PMIC pre-release data (April 2025)

Ideal for a Range of Smart and Medical Wearables

Wireless charging with Epson PMICs supports:

• Hearing aids (BTE, RIC, ITE) Proven in field deployments with global hearing aid brands since 2017.
  

• Skin-worn medical patches E.g., continuous glucose monitors, ECG patches, temperature sensors.
  

• Fitness and health trackers Enabling fast charge with no open ports or contacts.
  

• Smart earbuds and in-ear monitors Where space and comfort demand compact charging solutions.
  

• Implant-adjacent devices Wireless charging minimises skin breaches and improves hygiene.

By integrating power reception, control, and communication in one chip, Epson simplifies the power architecture for engineers developing the next generation of miniaturised, sealed wearables.

Get Started with Wireless Charging Design Support

Whether you're developing a medical patch, in-ear monitor, or sealed health tracker, Epson’s PMICs offer a reliable platform for efficient wireless charging for medical wearables.

Ineltek provides design-in support and access to samples, datasheets, and application guides. Contact us today to discuss how Epson PMICs with wireless charging can support your next-generation wearable project.