This article proposes a single-inductor dual-output (SIDO) buck converter which always deliveries continuous power to outputs. The proposed converter has adopted complementary adaptive-switching regulation (CASR) with a continuous current balancing (CCB) mechanism and an auxiliary current path to passively bypass output switches in turn. The proposed converter and its control scheme can enhance output current continuities and power efficiencies while decreasing voltage ripples and fluctuations due to equivalent series resistance (ESR) and equivalent series inductance (ESL) at each output. The prototype converter was fabricated with the 180-nm CMOS process and comprises a 4.7- $\mu$ H inductor with 92- $\text{m}\Omega$ DCR, two 10- $\mu \text{F}$ output capacitors, and a 10- $\mu \text{F}$ capacitor for the auxiliary current path. The measured results verified that the always-power-delivered (APD) SIDO converter can generate 1.8 and 3.3 V from 5 V with a combined type-3 compensator (CT-3C), while providing continuous current to each output. The peak efficiency was 94.9% with the load conditions of 150 mA for 3.3 V and 75 mA for 1.8 V. In addition, the overall efficiencies were measured higher than 90% in all operation ranges.