Concurrent Charge Distribution and Time-Optimal Control for Unordered Single-Inductor Dual-Output Converter

Single-inductor-multiple-output (SIMO) converters are pivotal for providing versatile V-F domains and fine-grained DVFS for many-core XPUs under stringent cost and size constraints. However, acceptable cross-regulation (CR) can only be promised in scenarios with less than 50% current discrepancies between output channels, making previous work unfeasible for frequent sleep/wake-up demands. Charging sequence reordering has emerged as a promising technique for mitigating last-channel CR in SIMO converters. However, conventional unordered control techniques introduce unwanted preceding-channel cross-regulation issues. The root cause is the mismatch in the loop response between the peak current (PC) control loop for the half-bridge and the channel-wise charge-driven loop. Although response mismatches can be alleviated through real-time calibration, significant CRs still occur during load transients with extreme channel discrepancies and hinder practical applications. To address these limitations, we introduce a calibration-free concurrent charge distribution and time-optimal control (CCD-TOC) technique. Moreover, a comparative study has explored the stability boundary and the benefits of an unfixed charging sequence. The experimental results of the single-inductor dual-output (SIDO) prototype demonstrate a transient CR of 0.176 mV/mA and a 92-mV (3.1%) undershoot against a 500-mA load step and a 400-mA (66.7%) channel discrepancy.