This paper introduces a single-inductor 4-phase hybrid switched-capacitor (4PSC) topology for integrated 48V-to-1V direct down conversion. Compared to state-of-the-art integrated high-ratio buck topologies, the proposed 4PSC topology achieves an efficiency comparable to or higher than double step-down (DSD) converters, while using one less inductor, thus lower cost and higher density; and a much higher efficiency than 3-level converters with both using one inductor. Simulations in 180-nm BCD verified the operation and performance, showing a peak efficiency of ~85% and ~91% with 48V-1V and 48V-2V conversions, respectively. A ~3% higher efficiency than DSD is observed at 48V-1V/5A conditions using lower-voltage devices.