Ultra-low voltage ripple in DC-DC boost converter by the pumping capacitor and wire inductance technique

Overall consideration including bonding wire effects is needed because conventional DC-DC boost converter used in energy harvesting systems suffers from large output voltage ripple in steady state and transient response. Thus, this paper proposed the pumping capacitor and wire inductance (PCWI) technique to suppress output voltage ripple to an ultra-low value. Small steady state voltage across the wire inductance (WI) and continuous WI current can be ensured by an additional pumping capacitor (PC). Moreover, even in case of an ultra-low output voltage ripple, the proposed pseudo-inductor current (PIC) technique regenerates the inductor current information to eliminate the instability problem in conventional ripple-based control techniques. Transient recovery time and output voltage variation can be reduced simultaneously. Test chip was fabricated in 0.18-μm 5V/24V CMOS process when input voltage of 1.8–5.5V is converted to 12.8V. Experimental results show the ratio of output voltage ripple and output voltage is reduced to 0.04%. Measured power conversion efficiency is around 92% at 100mA and 96% at 0.1mA.