An energy combiner for delivering electrical energy harvested simultaneously from individual energy harvesters to a single energy storage device such as a battery is presented. It is designed as a modular architecture to be handled as a subsystem, and supports an arbitrary number of energy harvesters which can be connected to the energy combiner in a hot-pluggable form. With the adaptive connection flows of a novel control algorithm, the energy harvested from each energy harvester can be transmitted to an energy storage device without interfering with each other. An evaluation system is implemented including the energy combiner circuit fabricated in a 0.13-μm CMOS process. The experimental results show that the energy combiner, with a low power consumption of 1.55 μW, achieves a maximum energy combining efficiency of up to 95% for three input sources.Index Terms-Energy harvesting, energy scavenging, energy management, energy combining 1549-7747 (c)

The feasibility of energy harvesting using the human body, which is used instead of a general antenna as an antenna in a low-frequency band to harvest energy included in an ambient electromagnetic wave, is investigated. Using the presented method, it is possible to harvest much more power in comparison with that possible with the previous method, in which a general antenna is used to harvest power in the high-frequency band. Also, this method can be easily applied to mobile devices because no antenna is required.

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This paper presents a transceiver module for human body communications whereby a spread signal with a group of 64 Walsh codes is directly transferred through a human body at a chip rate of 32 Mcps. Frequency selective digital transmission moves the signal spectrum over 5 MHz without continuous frequency modulation and increases the immunity to induced interference by the processing gain. A simple receiver structure with no additional analog circuitry for the transmitter has been developed and has a sensitivity of 250 µVpp. The high sensitivity of the receiver makes it possible to communicate between mobile devices using a human body as the transmission medium. It enables half‐duplex communication of 2 Mbps within an operating range of up to 170 cm between the ultra‐mobile PCs held between fingertips of each hand with a packet error rate of lower than 10−6. The transceiver module consumes 59 mA with a 3.3 V power supply.

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