Design of low-voltage and efficient energy-harvesting circuits is becoming increasingly important, particularly, for autonomous systems. Since the amount of energy that can be harvested from the surrounding environment is limited, the available output voltage of a harvester is low. Therefore, the design of a low-input-voltage (low-VIN) up-converter is critical to self-powered systems [1-3]. Moreover, the form factor is very constrained in applications such as wearable electronic devices and sensor networks. Recently, low-V IN charge pumps (CPs) for energy harvesting has been compared with DC-DC converters using a large inductor [1-3]. CPs introduced in  and  use the advanced process technology to push VIN down to the subthreshold region. The CP in  introduces a forward-body-biasing (FBB) technique, which improves the voltage conversion efficiency (VCE) for low VIN but shows poor power conversion efficiency (PCE). The CP in  achieves the lowest operation voltage. However, the design with a 10-stage CP provides low output power. This paper presents a CP with switching-body-biasing (SBB), adaptive-dead-time (AD), and switch-conductance (SW-G) enhancement techniques to improve the PCE for low VIN as well as to extend the maximum load current.