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.