Titanium bump in hydrogen maser and cesium clock require 3 000 and 3 500 V high working voltage to keep ultrahigh vacuum of storage bulb and cesium beam tube respectively, and needs to sense the output current of the high voltage power supplies to judge their working conditions. In this paper, buckcurrentfed pushpull topology and CockcroftWalton voltage doubling rectifying circuit are employed to develop the high voltage power supply for titanium bump. The snubber circuits of three buck current feed circuits, 50% duty cycle alternative driving circuit based on D flipflop and low output current sensing circuit are presented. The high voltage assembly adopts vacuum encapsulated process, singlesided surface mounted PCB design and the structure design of high voltage and low voltage cabins. This design decreases the voltage stress of the rectifier diodes. The high voltage power supply achieves 0.5% load regulation, 20～50 V wide input voltage range, 0～18 μA output current sensing, and passes vacuum discharging test, which satisfies the requirement of titanium bump in atomic clocks.