SLYT819 October 2021 BQ25980
One of the applications for a switched-capacitor converter is a battery charger for portable devices. The customizable capability of the USB PPS allows the unregulated switched-capacitor converter to charge the battery at a 50% fixed-duty cycle. The power loss in portable devices is limited by the thermal profile; sometimes the temperature rise is limited to as low as 10˚C. Battery chargers need to have a small footprint. The high efficiency and high power density of switched-capacitor converters could push the charging power much higher compared with the inductor-based regulated converter.
The BQ25980 [10] is a switched capacitor-based two-cell battery fast charger that can help achieve more than 98% efficiency between 2 A and 8 A, as shown in Figure 8-1. Placing two of the BQ25980 devices in parallel achieves the 120 W power together with 2.4 W/mm3. The battery charges from 0% to 100% within 15 minutes [11].