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The stability of conventional constant on-time control buck converter is constrained by the time constant, which is the product of the output capacitor and its equivalent series resistance (ESR). Specialty polymer capacitor which is mostly used as output capacitor for such a consideration although it limits the performance of converter. On the other hand, the multilayer ceramic capacitors are widely used in commercial power management ICs due to the advantages of low cost and ESR. However, the stability often confronts with the subharmonic problem caused by small time constant. A differential-zero compensator with the noise margin enhancement (DZC-NME) technique in constant on-time control buck dc-dc converter with output ceramic capacitor is proposed in this paper. Thus, the proposed DZC-NME technique not only eliminates the limit of large time constant but also tolerates the existence of equivalent series inductor (ESL) effect. Experiment results demonstrate small output ripple of 10 mV and high efficiency of 91% when ESR is smaller than 1 mΩ and large interference from ESL effect is 40 mV. Index Terms-Constant on-time control for buck converter, equivalent series inductor (ESL), multilayer ceramic capacitors (MLCC), power management.

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System-on-a-chip (SoC) applications need multiple power supplies with low noise for analog circuits and high efficiency for digital circuits. Thus, this paper proposes the priority-scheduled program (PSP) for single inductor quad output (SIQO) switching converter to manage energy delivery for four outputs. Consequently, SIQO converter with PSP can provides fast transient response and reduce cross-regulation. Besides, the level bypass detector (LBD) provides unlimited load range between each output through the shared inductor. The PSP cooperates with the LDB to transfer energy to low priority outputs to avoid overshoot at high priority outputs. With the two low-dropout regulator (LDR) working as buffers at low priority outputs, voltage disturbance can be filtered out. The SIQO converter fabricated in 40nm CMOS technology satisfies power requirements in portable electronics with 0.2% low noise, 15μs fast transient response, and cross-regulation smaller than 30mV.Keyword: Single inductor quad output (SIQO), cross-regulation, priority scheduled program (PSP), level bypass detector (LBD), fast transient.