New Industry Products

Buck-Boost IC Supports Simultaneous USB PD and Wireless Charging

December 05, 2017 by Paul Shepard

ROHM has announced the availability of dual-input boost-buck charging ICs that support 1 to 4 battery cells for notebook PCs, smartphones, and power banks that utilize the latest charging technologies such as wireless and USB Power Delivery (USBPD).

The BD99954GW/MUV generates a charging voltage from 3.07- to 19.2-V for 1 to 4 cells through boost-buck control for USBPD.

In addition, the industry's first dual-input charging system automatically switches charging operation without an MCU using an original built-in charging adapter function.

And support is provided for both USBPD and USB BC 1.2. This facilitates configuration of dual-mode systems capable of simultaneous charging via USBPD, wirelessly, or from an ac adapter.

Applications are expected to include notebooks, tablets, smartphones, portable batteries, wireless audio devices and any battery-powered devices requiring less than 100W of power.

A growing number of portable devices, including notebook PCs, are adopting the USB Type-C PD standard that can charge up to 100W, providing a common charging platform. At the same time wireless charging is gaining traction, increasing the demand to support both charging methods.

However, in order to deliver a wide power supply range required by USBPD, a boost function must be added to the system to charge 2-cell (about 8.4V) batteries from conventional 5V chargers.

Also, enabling two different charging methods to operate at the same time requires mounting charge ICs along with peripheral components as well as an MCU to control charge switching, presenting a significant barrier to introduction.

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In response, combining its USBPD IC with proprietary semiconductor technologies allowed ROHM to meet these needs and develop dual-input charging ICs that support both USBPD and wireless protocols in a single package.

The BD99954GW is available now and costs $3.14 in lots of 1,000 pieces. The BD99954MUV is currently available only in sample quantities with production scheduled to begin in January, 2018. The BD99954MWV-EVK-101 evaluation board is available now and costs $175.

Key Features

The BD99954GW and BD99954MWV provide the following 2 features that make it easy to configure a wireless charging environment

  1. Facilitates configuration of the industry's first simultaneous dual-mode charging system

To support the 2 predominant charging methods for the latest portable devices, ROHM developed the industry's first 2-input charging system. A built-in charging adapter discrimination function enables automatic switching between modes without an MCU.

This eliminates the need to mount and adjust external peripheral components such as transistors and resistors typically necessary for each charging system (for charge path switching and backflow prevention), significantly reducing both mounting area and design load.

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  1. Supports the latest USBPD standards through boost-buck control

Step-up/down control makes it possible to generate the charging voltages necessary for USBPD operation (5V to 20V). For example, when charging a 2-cell battery (~8.4V), boost-buck control enables step-down operation from 20V to 8.4V as well as step-up from 5V to 8.4V.

In addition, compliance with the popular USB BC1.2 and USBPD standards provides support for both conventional USB and the newest USB PD charging protocols.

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Evaluation Board