The structure of multilevel low-voltage power supplies with a self-clamped characteristic is proposed and experimentally demonstrated using a 0.5- $\mu \text{m}$ BiCMOS process. The power supply can achieve two output voltages by its intrinsically integrated structure with the values of 25.0 and 13.6 V when the applied high voltage is 90 V and the two load resistances are both 30 $\text{k}\Omega $ . The two output voltages also appear good stability. When the applied high voltage is changed from 90 to 150 V, its line regulation is 0.07%/V, and when the two load resistances vary within 30–100 $\text{k}\Omega $ , its load regulation is 9.6%. The proposed power supply is able to be integrated with most high-voltage devices without passive components and additional processes, which makes it considerable in the applications of high-voltage integrated circuits.