Proposal of an IC Suitable for Wireless and USBPD Environments

Last October, ROHM shipped a battery charging IC capable of automatically responding to various charging changes, such as wireless and USB PD (USB Power Delivery) charging. This is because the adoption of USB PD, which enables charging connector standardization by allowing up to 100W charging in mobile devices such as laptops, has recently increased, and the release of devices supporting two or more charging methods has also increased.

For example, most smartphones released in the market in the second half of this year, such as the iPhone 8 and Galaxy Note, already support USB charging and wireless charging as standard. Nintendo and Huawei laptops are also already releasing devices that support USB PD to the market.

Existing multi-charging methods, such as boost and buck charging using AC adapters supporting 5V / 1.5 ~ 3A and wireless charging based on the WPC Qi standard, provide convenience to users when charging devices, but increase the burden of multi-design for designers developing mobile devices equipped with batteries.



ROHM has released the BD99954, a charging control IC capable of distinguishing inputs between USB PD and wireless charging ICs, to overcome this complex design environment. The IC BD99954 replaces the 2 transistors and 4 resistors required for the two existing charge inputs with 2 BD99954s, and is designed to enable charge switching without the need for a FET drive input control microcontroller required for the existing charging system.

This intelligently supports two charging paths, USB PD and wireless charging, with a single charging IC, thereby enabling the simultaneous implementation of the latest charging methods with the utmost simplicity. This allows developers to dramatically reduce the burden of multi-design.

FET-driven input control that does not require a microcontroller

In conventional systems, the design of an input control microcontroller for driving FETs is essential due to the use of transistors and resistors. However, the BD99954 automatically steps up and down the charging voltage range between 20V (such as USB PD) and 5V (common for conventional USB and wireless charging). This eliminates the need for existing microcontroller functions, thereby reducing mounting area and shortening development time. For example, when charging a 2-cell battery (8.4V), charging to 8.4V is possible by stepping down with a 20V input, while charging to 8.4V is possible by stepping up with a 5V input.

The BD99954 2-system charging compatible IC is intended for battery-powered mobile devices that operate at 100W or less, such as laptops, tablet PCs, smartphones, power banks, wireless audio, and battery-powered displays, and the BD99954MWV-EVK-101, an evaluation board for development support, is also currently on sale.