This paper presents a high-voltage (HV) driver for switching a buck converter. The circuit is based on 3-stacked CMOS using gate control circuits to drive maximum current which indicates minimized on-resistance of the HV-driver thus achieving faster switching. The circuit is designed and fabricated using 65 nm CMOS TSMC process technology with a nominal voltage of 2.5 V and with a supply voltage of 5.5 V. Since the design is based on stacked CMOS transistors, the circuit is technology-independent. The initial on-resistances of the driver pull-up and the pull-down paths have an improvement of 75% and 36% respectively. Due to a buck converter switched by the designed HV-driver, output voltages in the range of 0.45 V to 2.45 V can be achieved from different high supply voltages in the range of 3.5 V to 5.5 V. The circuit occupies an area of 0.187 mm².