Dual-frequency SIMO power converters for low-power on-chip power grids in SoCs

This paper introduces the Dual-Frequency Single-Inductor Multiple-Output (DF-SIMO) power converter topology as a cost-effective and power-efficient method for implementing a large number of on-chip power supplies (i.e. on-chip power grids) in nanometer CMOS System-on-Chip (SoCs). The proposed topology decouples the rate of energy conversion at the input of the converter from the rate of energy distribution to the outputs, and thus, output bandwidth and dynamic behavior become no longer limited by the switching frequency at the input side. Low switching frequency at the input side can be used to preserve high power conversion efficiency, while high switching frequency for energy distribution at the output side can be used to reduce the output capacitors to integrate-able levels where they can be implemented on-chip. This limits off-chip components to a single inductor and reduces the package pin count, which results into a lower overall cost per power supply. Dynamic performance is also improved due to the high frequency energy distribution. A 5-output DF-SIMO buck converter design in 45nm CMOS is introduced as an application to the proposed concept.