ROHM has developed wireless charging modules “BP3621” and “BP3622” that easily realize wireless power supply for small and thin devices

Update: November 22, 2021

~The use of optimized antenna layout design technology helps to shorten the development cycle~

The world-renowned semiconductor manufacturer Rohm (headquartered in Kyoto, Japan) has developed a set of small wireless charging Modules “BP3621 (transmitting module)” and “BP3622 (receiving module)” that integrate antennas and Circuit boards, using this set of modules It can easily realize the wireless charging function of small devices such as smart tags and smart cards and computer peripherals.

In recent years, in many applications such as smart phones and smart watches, wireless power supply functions that can eliminate charging ports and improve waterproof and dust-proof performance are being accelerated. However, the frequency of the existing wireless power supply standards is low, and the miniaturization of antennas is restricted in order to comply with the standards. Therefore, the industry expects higher and higher standards and methods for better generalization of small equipment. In addition, since the power supply efficiency of the wireless power supply function will change due to the shape, size and distance of the antenna, it is necessary to repeatedly perform trial production, adjustment, and evaluation on the entire Electronic device before installing the wireless power supply function. In terms of layout design, heavy development burden has always been a big problem. In this context, ROHM has developed a 13.56MHz wireless charging module, which can enable small and thin devices to easily achieve wireless power supply.

The new product is a small module with a size of about 20mm~30mm square, using the 13.56MHz high frequency band, and adopting optimized antenna (coil) and layout design technology, which can provide up to 200mW of power supply, which is very suitable for building a small wireless power supply system. Not only is it easy to install in small and thin devices that have been difficult to achieve wireless power supply in the past, but it also improves the flexibility of shell design by adopting a circuit board structure with a flat back. In addition, by using the transmitter module and the receiver module in pairs, the development time required for trial production, adjustment, and evaluation required to optimize power supply efficiency can be shortened. Not only that, the built-in antenna also supports two-way data communication and NFC Forum Type3 Tag*1Communication, which will help expand the communication function of the application.

The new product has been put into mass production in October 2021, and is expected to start online sales in the near future. The production base is ROHM Apollo Co., Ltd. (Fukuoka Prefecture, Japan).

In the future, ROHM plans to continue to expand the product lineup of small and high-power modules to further expand the applicable range.

1. The integrated module of antenna and circuit board can greatly shorten the development cycle and easily realize the wireless power supply function

The new product is an integrated antenna and circuit board module, which uses ROHM’s own simulation-based antenna design technology and circuit board layout design technology that can reduce wiring losses. By using the transmitter module and the receiver module in pairs, a power supply of up to 200mW can be achieved. Compared with the case where the antenna and the control circuit are separately configured, the feed characteristics can be guaranteed, so product evaluation can be carried out without the need for antenna design, layout design, and feed characteristics evaluation. This can significantly shorten the development cycle and the design burden of circuit board modification, and can easily realize the wireless power supply function.

2. Adopt13.56MHzThe high frequency band realizes the miniaturization of the module, which helps to improve the flexibility of the housing design

The new product adopts the 13.56MHz high-frequency magnetic field resonance method*2, the antenna is smaller, and it is suitable for small devices such as smart tags and computer peripherals such as mice. The new product is a small module integrating antenna, matching circuit and wireless charging IC, which is difficult to achieve with existing wireless power supply standards. In addition, as a wireless power supply product, it can not only eliminate the charging port, improve the waterproof and dustproof performance, but also make it easier to stick on the shell by adopting the circuit board structure with a flat back, which helps to simplify the shell structure and improve the design. flexibility.

3. The antenna with built-in module helps to expand the data communication function of the application product

Since the new product uses the same 13.56MHz high frequency band as the NFC communication standard, the antenna with a built-in module can support both power supply and communication functions at the same time. It can carry out two-way data communication (communication speed of 212kbps, up to 256 bytes) and NFC Forum Type3 Tag communication, which helps to expand the data communication function of application products, such as data security transmission and rewriting of sensor data, device information and authentication information, Firmware download, sending of battery output voltage value, etc.

On the ROHM official website, the following data required to build a wireless power supply function is provided:

◇Technical Specification ◇Application Guide

Small devices such as smart tags, smart cards and ID cards,

Computer peripherals such as mice and remote controls, small devices used in the healthcare field

*1) NFC Forum Type3 Tag:

NFC (Near Field Communication) is a short-distance communication technology that uses a frequency of 13.56MHz to communicate over a short distance. Its specifications are defined by the NFC Forum. Type3 is one of the label standards.

*2) Magnetic field resonance method:

A wireless charging method that causes the antenna (coil) for power transmission and reception to enter a resonance state to transmit magnetic field vibration and flow current.