A Digitally Controlled Fully Integrated Voltage Regulator With 3-D-TSV-Based On-Die Solenoid Inductor With a Planar Magnetic Core for 3-D-Stacked Die Applications in 14-nm Tri-Gate CMOS

A fully integrated digitally controlled buck voltage regulator, featuring hysteretic and pulse frequency modulation control for maximum light load efficiency, with 3-D throughsilicon-via-based on-die solenoid inductor with a planar magnetic core in 14-nm tri-gate CMOS, demonstrates 111 nH/mm2inductance density and 80% conversion efficiency. The inductance density demonstrated is 20× higher than comparable on-die lateralor spiral-based inductor densities leading to higher light load efficiency.