A Low Input Voltage Charge Pump for Energy Harvesting

Abstract

Abstract This paper proposes a low input voltage charge pump using 0.18um CMOS process for energy harvesting. There are two main sections in the charge pump system: Low Voltage Charge Pump (LVCP) and High Voltage Charge Pump (HVCP). In the LVCP, a negative charge pump is utilized to improve the efficiency at low input voltage, Dynamic Body Bias (DBB) and switch-conductance enhancement techniques are applied to a unit stage of the two-stage charge pump. In the HVCP, the charge pump circuit utilizes charger transfer switches (CTS) with a complementary banch scheme to significantly reduce undesired charge transfer, and an optimized gate control strategy is applied to further decrease the power loss caused by undesired charge transfer. The simulation result demonstrates that the proposed circuit can achieve 97% voltage conversion and drive 800uA load current at 0.6V input voltage. In the region of 0.4V to 0.6V input voltage, the circuit performs well with the load resistance of 10K ohms.