A compact current-mode boost converter for battery-operated portable devices is presented in this paper. With the help of depletion-mode MOSFET, the chip's volume reduces and input voltage extends from 2.5 V to 10 V. Using a 0.5 mum BCD process, the maximum efficiency of this converter can reach 90% at fixed frequency 1.4 MHz. In addition, a single input error amplifier and dead-time control circuit for this design are proposed in the paper. The simulation results and measures verify the function of the proposed structure.