Fully tunable software defined DC-DC converter with 3000X output current & 4X output voltage ranges

This paper presents a fully integrated, software defined capacitive DC-DC converter. The converter implements K-F-C tuning (K = conversion ratio, F = frequency and C = capacitance) in real time so as to accommodate any output load. It has a 4X tunable output voltage, supports a 3269X output load current range while achieving a peak efficiency of 82.1%. This design introduces an accumulation floating junction MOS capacitor that is used for the 18.3 fF/μm ² bucket-capacitors with less than 2μA/mm ² leakage. This leakage is 40X lower than standard MOS capacitors. The converter transforms a 1.0V input to a 0.25-0.95V output for a 0.13mA-425mA load range while maintaining better than 70% efficiency. The power density for better than at 70% efficiency is 1.05W/mm ² (@ V _out =430mV) while peak value is 2.15/mm ² . Load regulation is implemented using capacitive and frequency tuning in digital and analog domains respectively. The design was fabricated in TSMC 65nm.