This paper presents an ultra-low power controlcircuit for a DC-DC boost converter targeting implantablethermoelectric energy harvesting applications. Efficiency of theinput converter is enhanced by utilizing zero-current switchingtechnique. Adaptive delay between ON states of switches assureszero-voltage switching of synchronous rectifier and reducesswitching losses. The control circuit employing both techniquesconsumes an average power of 620nW. This allows the converterto operate from harvested power below 5μW. For voltageconversion ratios above 20, the proposed circuits and techniquesdemonstrate efficiency improvement compared to the state-of-the-art solutions.
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