Hardware-software co-design of an embedded power management module with adaptive on-chip power processing schemes

This paper presents an embedded power management module with adaptive on-chip power processing schemes, tailored for next-generation power-aware VLSI systems. The module comprises a single-inductor multiple-output (SIMO) power converter and a software-defined, digital controller. By using a digital control, the entire converter can be integrated with microprocessor units (MPUs). This enables a hardware-software co-design, where effective power processing carried out at the software level can be directed to generate the most optimal voltages at the hardware level. Such an embedded power management module leads to an integrated and autonomous system-on-chip (SoC) design, which is independent of additional external hardware control. In this design, each power output from the SIMO converter provides a step-up/down voltage conversion, thereby enabling a wide range of variable supply voltage. An adaptive global/local power allocation control algorithm is employed to significantly improve DVS tracking speed and line/load regulation, while the still retaining low cross regulation. Designed with a 180-nm 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 very fast load transient response of 3.25 μs is achieved, in response to a 67.5-mA full-step load current change.