A Light-Load Efficient Fully Integrated Voltage Regulator in 14-nm CMOS With 2.5-nH Package-Embedded Air-Core Inductors

Fully integrated voltage regulators (FIVRs) offer many advantages, such as fine-grained power management, fast transient response, and reduced form factor. This article addresses light-load efficiency in FIVRs with nH-scale air-core inductors. The challenges of implementing efficient discontinuous conduction mode (DCM) operation at high switching frequencies are discussed, which include zero current detection, inductor ac-loss effects, and power delivery network (PDN) resonances. A prototype in 14-nm CMOS is presented, which shows the DCM operation at up to 70 MHz with a peak efficiency of 88% for 1.6–1.2-V conversion.