11.3 A 1.8W High-Frequency SIMO Converter Featuring Digital Sensor-Less Computational Zero-Current Operation and Non-Linear Duty-Boost

Power delivery components are critical for meeting size and weight requirements of ultra-mobile electronic systems. The Land C passives in power delivery sub-systems occupy $> 50 \%$ of the total PCB area, often dictating the thickness of handheld devices. On the other hand, advanced power management capabilities demand multiple individually controllable voltage domains with high conversion efficiency to maximize battery life. These voltage domains can be supplied by multiple buck converters that increase platform size & weight, or by a single converter followed by multiple point-of-Ioad LDOs that degrade overall power efficiency. Single-inductor multiple-output (SIMO) converters promise a more balanced solution for these critical trade-offs [1–4] but are vulnerable to significant cross-regulation preventing it from scaling to > 1W powers [1]. While SIMO converters in continuous conduction mode (CCM) can enable higher power with specialized circuits to reduce cross regulation [4–5], they are susceptible to random simultaneous load transients across multiple outputs that can disrupt a balanced inductor current waveform. On the other hand, isolating inductor in discontinuous conduction mode (DCM) and separating each output's inductor cycle via an independent-charging scheme can effectively eliminate cross-regulation. However, large inductances with lower peak currents can limit output power [1–3] and low operating frequency in DCM can worsen droops due to longer wait times, thus necessitating larger output decoupling capacitors.