This paper presents a photovoltaic energy harvesting (PVEH) system achieving both high Maximum Power Point Tracking (MPPT) efficiency (η _MPPT) and power conversion efficiency (η _CONV) across a wide input power dynamic range (DR), employing a direct input power-to-digital converter (PDC) and an adaptive power-scalable MPPT scheme. The proposed PVEH achieves >98% (with a peak of 99.9%) η _MPPT across a 100,000 × DR (10 μ W to 1 W), representing a 10 × improvement over the state-of-the-art, as well as a competitive η _CONV of >82% (with a peak of 92%) across the same DR.