Fully Integrated Switched-Capacitor DC-DC Converter With Self-Recovery Hysteresis Control

Switched-capacitor DC-DC converters are suitable for on-chip power circuits. Hysteresis control with a high bandwidth comparator can achieve high efficiency over a wide load range and respond quickly to steep load fluctuations. However, hysteresis control cannot withstand large current spikes above its allowable load current. This paper proposes a self-recovery hysteretic switched-capacitor DC-DC converter. By introducing a self-recovery mechanism and utilizing a continuous comparator, the converter responds quickly to steep load fluctuations. Furthermore, all control circuits use the output voltage as the supply voltage. We design the DC-DC converter using our proposed technique in a commercial 65 nm low-power CMOS process. It operates over $0.1 \sim 9.11 \mathrm{~mA}$ with a total capacitance of 1 nF and deals with steep spike-like load fluctuations without stopping hysteresis control. It can recover quickly for a current spike of as high as 35 mA within only 150 mV of voltage drop.