ScholarWorks@성균관대학교

초록

A novel energy-harvesting interface (EHI) circuit that employs a continuously scalable-conversion-ratio (CSCR) switched-capacitor (SC) DC-DC converter is introduced in this paper. CSCR converters inherently sustain high power conversion efficiency across a wide voltage conversion ratio (VCR), making them well suited for EHI applications. Realizing wide-range maximum-power-point tracking (MPPT) with a hill climbing algorithm, however, demands accurate on-chip power estimation. Recent EHI works failed to provide such estimation, neglecting the unit step voltages in the internal flying-capacitor network, hence constraining the attainable MPPT range. To overcome this limitation, a compact power monitor that explicitly accounts for the unit step voltages in the internal flying-capacitor network is introduced. The monitor employs a capacitive divider and is tightly coupled to an exponential digitally controlled oscillator (DCO), yielding precise power measurements over a broad frequency span. Fabricated in a 180 nm CMOS process, the prototype delivers up to 6.05 mW while achieving 90.4% end-to-end efficiency. It sustains ≥ 97% MPPT efficiency over a 14.6× dynamic-power range (130 μW-1.9 mW), 3.4× wider than previously reported CSCR-based harvesters. The proposed architecture thus offers an efficient and scalable solution for next-generation energy-harvesting systems.

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