Area Efficient High-Performance Digitally Controlled Power Management Unit

Abstract

Power management unit (PMU) is commonly used to manage power modules to achieve high efficient performance for integrated circuits. Inside the PMU, controllers that belong to different power modules could be pretty much similar. If the discrete feature of the digital control can be gainfully arranged, we can use only one controller to operate all the power modules inside the PMU, which can reduce circuit area and save cost. This article proposes a pipeline concept to realize this idea. To achieve high performance, this article also introduces a phase sequence interchange technique to reduce the cross regulation problem of the single inductor dual outputs converter and an autotuning charge balance algorithm (AT-CBA) to enhance the transient response. The PMU is fabricated in Taiwan Semiconductor Manufacturing Company (TSMC) 0.18 μm CMOS manufacturing process for functional validation. Experimental results show that the pipeline controlled PMU can simultaneously output six voltages with extremely low cross regulation. The proposed AT-CBA also successfully make both buck converter and low-dropout achieve near-optimal transient response in 40 mV/5 μs and 120 mV/1 μs, respectively.