A fully-integrated switched-capacitor 2∶1 voltage converter with regulation capability and 90% efficiency at 2.3A/mm²

A 28 nm FDSOI Integrated Reconfigurable Switched-Capacitor Based Step-Up DC-DC Converter With 88% Peak Efficiency

“…Table.II shows the performance comparison with previous works on step-up switched-capacitor DC-DC converters. This work achieves a peak-efficiency as high as 88% even with using MOS capacitors, which have a much lower density and higher parasitic capacitance as compared to MIM [6] and trench capacitors [5]. Furthermore, the output voltage range is much higher than previous works, thanks to the reconfigurability of the converter.…”

“…Furthermore, the output voltage range is much higher than previous works, thanks to the reconfigurability of the converter. The (unoptimized) area of the proposed converter is higher as compared to [5] and [6]. This is because a large portion of the area is occupied by the load capacitor, which has to be implemented with a low density MOM capacitor to support a high output voltage of 2.4V.…”

“…As seen from Table.II, [5] achieves a slightly higher peak efficiency (90%) because of the use of highly dense (200 fF/µm 2 ) trench capacitors, which also have a much lesser bottom-plate parasitic capacitance as compared to a capacitor implemented with regular MOS transistors. Bottom-plate parasitic loss is a major loss component for the power levels we are dealing with.…”

“…Fully integrated switched-capacitor (SC) based converters can achieve high conversion efficiency [5]- [7] and power density [8], which are key for on-chip implementation. To benefit from CMOS scaling, SC converters should utilize core transistors as charge-transfer switches, which offer lower on-resistance (R on ) with reduced capacitance.…”

“…Additionally, a topology is proposed for the 5/2 mode which improves efficiency by reducing the bottom-plate parasitic loss as compared to a conventional series-parallel topology [12]. The converter was implemented in a 28nm FDSOI process [13]- [15] using only on-chip MOS and MOM (Metal-Oxide-Metal) capacitors that do not require any extra fabrication steps, unlike MIM (MetalInsulator-Metal) [6] and trench capacitors [5].…”