System Architecture for Conditioning the Asymmetric and High Crest Output of Triboelectric Generators

This letter presents an integrated system comprising of a direct current triboelectric generator (dc-TEG) and an associated power management circuit (PMC). The asymmetric and high peak-to-average ratios of the output are two major bottlenecks that limit the charging efficiency of TEGs. The high intrinsic impedance of these generators further complicates the charge transfer to a large capacitive load. This letter presents a DC-TEG that generates unidirectional current output without rectification. A circuit based on a two-stage series–parallel switched capacitor configuration is then used to condition the electrical output of the transducer. This circuit serves the dual purposes of maximizing power extraction by interfacing the device with a matched low-capacitive load and maximizing the dc voltage across the final capacitive load by lowering the output's peak amplitude. Experimental results indicate the conditioned output of the integrated system charges a 0.1
$\mu \text{F}$
capacitor to a dc voltage of 0.81 V, which is 4.1× and 1.5× the voltage obtained when charging using an ac-TEG device and standalone dc-TEG device, respectively. The system demonstrates a peak efficiency of 84.4% for a 0.79
$\mu \text{W}$
maximum output power across the parallel network of 0.1
$\mu \text{F}$
capacitor and 1
$\text{M}\Omega$
resistor.