Abstract

In this report, an on-line power meter is developed to monitor the power demand of each sub-converter in a single-inductor multiple-output DC-DC converter. This converter is tailored for DVS-enabled multicore systems. In this design, each power output employs a step-up/down voltage conversion, thereby enabling a wide range of variable output voltage. This is beneficial to dynamic voltage scaling (DVS) techniques that are in high demand by low-power multicore systems. With a multi-mode control algorithm, DVS tracking speed and line/load regulation are significantly improved, while the converter still retains low cross regulation. Designed with a 180-nm digital CMOS process, the converter precisely provides three independently variable power outputs from 0.9 to 3.0 V, with a total power range from 33 to 900 mW. A fast load transient response of 3.25 us is achieved, in response to a 67.5-mA full-step load current change. The converter can operate robustly at any input supply level from 2.0 to 3.3 V, leading to a superior line regulation of 4.6 mV/V. The design provides a cost-effective solution to robust, fast-transient, DVS-compatible, on-chip power supplies.