Design of a Switched-Capacitor DC-DC Converter With a Wide Input Voltage Range

A triple-mode step-up/step-down switched-capacitor DC-DC converter is proposed, and it can work with a wide input voltage range. There are three operational modes in the proposed converter: triple-step-up, double-step-up, and step-down modes. A built-in clock generator was designed to generate a constant switching frequency, independent of the input voltage. The proposed circuit was implemented by a 0.35-μm CMOS mixed-signal 2P4M 3.3/5 V polycide process with a die area of 1.56×1.47 mm
²
. The output voltage is fixed at 3.3 V, while the input voltage range is 1.8-5 V. The maximal load current for a 1.8-V input voltage is 10 mA, while it increases to 30 mA when the input voltage is larger than 3 V.