On-chip hybrid power supply system for wireless sensor nodes

With the miniaturization of electronic devices, small size but high capacity power supply system appears to be more and more important. A hybrid power source, which consists of a fuel cell (FC) and a rechargeable battery, has the advantages of long lifetime and good load following capabilities. In this paper, we propose the schematic of a hybrid power supply system, that can be integrated on a chip compatible with present CMOS process. Besides, considering the problem of maximizing the on-chip fuel cell´s lifetime, we propose a modified dynamic power management (DPM) algorithm for on-chip fuel cell based hybrid power system in wireless sensor node design. Taking the wireless sensor node powered by this hybrid power system as an example, we analyze the improvement of the FC-Bat hybrid power system. The simulation results demonstrate that the on-chip FC-Bat hybrid power system can be used for wireless sensor node under different usage scenarios. Meanwhile, for an on-chip power system with 1cm² area consumption, the wafer-level battery can power a typical sensor node for only about 5 months, while our on-chip hybrid power system will supply the same sensor node for 2 years steadily.