Fast-Charging trends and challenges for single-cell batteries using high input voltage
As the functions of portable devices increase, the need for more battery capacity continues to grow. Larger batteries can mean longer charge time, but users also demand less charge time or the ability to charge the battery more fully within the same amount of time. To meet this stringent requirement, the charge current must be increased significantly. A traditional 5V USB adapter with limited input power can no longer satisfy this fast-charging demand. Industry initiatives to support higher adapter power such as USB Type-C and other methods to provide USB-compatible, high-voltage input are becoming more popular. As system designers try to take full advantage of new high-voltage adapters, they are faced with new challenges. These include how to improve charging efficiency with minimum cost impact, how to break the thermal loss barrier, and how to minimize the impact of battery path impedance with much higher charging currents. In this session we discuss these challenges and provide possible design solutions.