A fast-response single-inductor dual-output hysteresis-current-controlled DC–DC buck is proposed for enhancing the transient characteristics of switching DC–DC converters and fabricated with TSMC 0.35 μm DPQM CMOS processes. By adopting a hysteresis-current-controlled DC–DC buck converter, it is demonstrated that the hysteresis-current-controlled technique have improved dynamic response of load variations whether the load current is light or heavy. Fast-response structure achieves 5 μs response with load variation which betweens 10 and 110 mA. Also proposed single-inductor dual-output structure is a time-multiplexing circuit to decrease the influence of cross regulation than that of previous designs. With a 3.6 V input power supply, the DC–DC buck converter precisely provides an adjustable power output with a voltage range from 0.9 to 3 V.