Three-level buck controllers boost USB-C efficiency
Two voltage controllers from Renesas feature a three-level buck topology for battery charging and voltage regulation in USB-C systems. With wide input and output voltage ranges, the RAA489300 and RAA489301 are well-suited for multiport USB-PD chargers, portable power stations, robots, drones, and other high-efficiency DC/DC applications.
The three-level topology adds two switches and a flying capacitor to a conventional buck converter. The capacitor lowers voltage stress on the switches, enabling the use of lower-voltage FETs with better efficiency and reducing conduction and switching losses. It also allows a smaller inductor, with ripple only about 25% of that in a two-level design, further cutting inductor losses.
In addition to the three-level buck configuration, the controllers offer passthrough mode in both forward and reverse directions, enabling high efficiency when input and output voltages are equal. Key parameters are programmable via an SMBus/I²C-compatible interface.
The devices differ in voltage range and switching frequency. The RAA489300 operates from an input of 4.5 V to 57.6 V and an output of 3 V to 54.912 V, with a programmable switching frequency up to 400 kHz (800 kHz at the switching node). The RAA489301 supports an input of 4.5 V to 24 V and output of 3 V to 21 V, with a programmable frequency up to 367 kHz (734 kHz at the switching node).
The RAA489300 and RAA489301 are available now in 4×4 mm, 32-lead TQFN packages.
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