This paper presents a low-dropout (LDO) regulator structure which sets its bias current adaptively based on its load current for energy efficiency. Over-current and short-circuit protection functions are implemented in the LDO with almost zero quiescent current addition. The proposed structure is inherent stable without output capacitance requirement. The proposed LDO was fabricated with a standard 0.18 μm technology with measured quiescent current consumption of 11nA under no-load condition and a maximum available load current of 50mA. The measured line and load regulations were 0.86mV/V and 0.2mV/mA, respectively.