An on-chip high-voltage charge pump circuit realized with the polysillcon diodes in standard (bulk) CMOS process is presented in this paper. Because the polysilicon diodes are fully Isolated from the substrate, the output voltage of the charge pump circuit is not limited by the junction breakdown voltage of MOSFETs. The polysilicon diodes can be implemented in the standard CMOS processes without extra process steps. The proposed charge pump circuit has been fabricated in a 0.25-μm 2.5-V standard CMOS process. The output voltage of the 12-stage charge pump circuit can be pumped up to 28.08 V, which is much higher than the n-well/p-substrate breakdown voltage (18.9 V) in a 0.25-μm 2.5-V standard CMOS process.