Low-Voltage Capacitive-Based Step-Up DC-DC Converters for RF Energy Harvesting System: A Review

Bulky off-chip inductors are predominantly adopted for inductive-based step-up DC-DC converter in RF energy harvesting (RFEH) systems, which impose a restriction in physical form factor for miniaturized device. This article review and explores the capacitive-based step-up DC-DC converters (charge-pump) as voltage boosting element for low-voltage RFEH systems. An overview of RFEH is established and a comprehensive review of CMOS charge-pump is followed along with the complementary frequency generation circuit used as a clocking element. Key design considerations of charge-pump circuits are included here along with recommendations to circumvent its bottlenecks for future development in RFEH systems.