New wireless charger modules facilitate wireless charging in thin and compact devices

ROHM has designed compact wireless charger modules with an integrated antenna board: the BP3621 (transmitter) and the BP3622 (receiver). The new modules enable creators to add wireless power supply functionality to smaller devices, including smart tags/cards or PC peripherals.

Wireless power supplies are increasingly adopted in smartphones, smartwatches, and other compact devices. By using wireless power technology, devices can enhance water and dust resistance by eradicating terminal contacts. However, the existing low-frequency standards for power transmission – together with restrictive antenna designs – limit the degree of miniaturisation that can be accomplished. These limiting factors are growing the demand for standards and methods universally adopted in compact devices. Also, the power transmission efficiency can vary – depending on the antenna size, shape, and distance. Therefore, it is often necessary to repeat prototyping, adjusting, and evaluating the system – representing a significant development burden for antenna design and layout.

In response, the company has produced 13.56MHz wireless charging modules that enable users to effortlessly add wireless power functionality to thin and compact devices. Measuring only 20mm² to 30mm² each, the devices include an optimised antenna (coil) layout. It allows a compact wireless charging system configuration utilising the 13.56MHz frequency band to deliver 200mW. The full-flat backside board structure enables mounting in thin, compact devices – contributing to better flexibility in chassis design than traditional solutions. Moreover, utilising the transmitter and receiver modules as a pair can greatly reduce the development load for prototyping, evaluation, adjustment, and other processes required to perform high-efficiency wireless charging. At the same time, the built-in antenna supports bi-directional data communication and NFC Forum Type 3 Tag operation, expanding applicability.

Application examples include compact devices such as smart tags, smart cards, and ID cards; mice, remote controls, and other PC peripherals; and portable healthcare equipment.