A 4:1 Switched Capacitor Converter With Low Flying Capacitors Voltage and High Efficiency

In this article, a 4:1 switched capacitor converter is derived. Compared with the Dickson 4:1 converter, the voltage of flying capacitors is lower, and thus, the effect of dc bias on multilayer ceramic capacitor (MLCC) is reduced. With a limited number of MLCCs, the proposed converter achieves a higher efficiency, and it is suitable for the applications with limited volume such as mobile phone fast charging. A 20-V to 5-V prototype is built with 24 X7R MLCCs in 0805 package, and its efficiency is 1.7% higher than the Dickson 4:1 and 1.1% higher than the series-parallel 4:1 at 16-A output current.

Automated summary

In this article, a 4:1 switched capacitor converter is proposed. It achieves a higher efficiency compared to the Dickson 4:1 converter by reducing the voltage of flying capacitors, thus mitigating the effect of dc bias on multilayer ceramic capacitors (MLCCs). This converter is suitable for applications with limited volume, such as mobile phone fast charging. A 20-V to 5-V prototype with 24 X7R MLCCs in 0805 package is built, and it has a 1.7% higher efficiency than the Dickson 4:1 and 1.1% higher than the series-parallel 4:1 at 16-A output current.