A Power Cloud System (PCS) for High Efficiency and Enhanced Transient Response in SoC

Abstract

Tradeoff between power efficiency and transient performance usually comes out during the design consideration of a power module. A configurable power supplying implementation named as the power cloud system (PCS) is proposed to handle different load conditions for simultaneously improving the power efficiency and the transient response in order to meet the system-on-chip (SoC) requirements. At heavy loads, the switching regulator takes over the energy delivery scheme in the PCS with the fast transient technique. An auxiliary power unit, which activates hybrid operation in both medium and light loads, can realize the low-dropout (LDO) regulator to provide a supplementary energy immediately in transient duration and be the high-side power switches of the switching regulator to minimize the power loss. Besides, owing to its low quiescent current of an LDO regulator, it can directly operate under the ultralight-load condition. Therefore, the satisfactory power conversion efficiency and the load transient response can be derived over a wide load range, which will certainly meet the power requirement for different operated functions in the SoC. The chip was fabricated by a 0.25-mu m CMOS process, and the experimental results show the improvements of 56% transient dip voltage and 25% transient recovery time in hybrid operation, as well as a peak efficiency of 94%.