Battery charger IC powers low-voltage rechargeable batteries

(Source: Rohm)

Rohm Co., Ltd. has developed a new battery charger IC for low-voltage charging of wearable devices such as wireless earbuds and thin, compact IoT devices such as smart displays powered by rechargeable batteries. The BD71631QWZ supports low-voltage charging for lithium-ion batteries as well as new types of rechargeable batteries including all-solid and semi-solid state.

“In recent years the need for safer, higher density rechargeable batteries has led to the development of new battery types,” said Rohm. “This includes all-solid/semi-solid types using novel materials for the electrode part and batteries that adopt different terminal compositions.”

The challenge is that many of the latest rechargeable batteries are small and thin, requiring low voltage charging in the 2-V to 3-V range, and at the same time, there are currently no battery charger ICs that can handle a wide voltage range, said the company.

The BD71631QWZ offers low-voltage charging over a wide range from 2 V to 4.7 V by improving the stability of the internal circuit, said Rohm. The charging voltage can be set by changing the external resistor, reducing design load when changing batteries, which is unlike general battery charger ICs, said the company.

(Source: Rohm)

Rohm said each charging characteristic like charge current/voltage and termination current can be set for CCCV charging, providing optimal charging based on the characteristics of the batteries, and even if the battery needs to be changed during application design, it can be designed without reselecting components.

In addition, reducing the battery standby current down to 0 μA in the standby state and incorporating a variety of protection functions can contribute to longer operating times in rechargeable devices and improved safety during charging, said the company.

To meet space constraints in wearables and other small devices, the BD71631QWZ is housed in a compact package measuring 1.8 × 2.4 × 0.4 mm. The footprint is reportedly 50% smaller than standard products with a 60% lower mounting height.

Available in volume production, the BD71631QWZ is priced at $0.93/unit for samples, excluding tax.  An evaluation board, the BD71631QWZ-EVK-001, is also available. The BD71631QWZ and evaluation board can be purchased from Rohm’s online distributors: Digi-Key, Farnell, and Mouser.

(Source: Rohm)