A charge pump structure with regulated output voltage (Voutmain), comprising: - an output terminal to provide the output voltage (Voutmain), - a charge pump to generate the output voltage (Voutmain) as a function of an input supply voltage (Vsup), and - a control circuit to limit a level of the output voltage (Voutmain), wherein the control circuit comprises a current branch having a variable resistance, wherein the current branch is arranged between the output terminal and a ground potential, wherein the control circuit comprises a transistor to provide a controllable current path having the variable resistance, wherein the transistor is arranged in the current branch, characterized in that the control circuit comprises another charge pump to generate a control voltage (Voutref) as a function of a reference voltage (Vref), wherein the level of the output voltage (Voutmain) is controlled by the control voltage (Voutref) such that the output voltage (Voutmain) does not exceed a threshold value, wherein the transistor comprises a control terminal to apply the control voltage (Voutref) to control the variable resistance of the controllable current path, wherein the transistor is configured to be operated such that the controllable current path has a high resistance, when the level of the output voltage (Voutmain) of the charge pump is below the threshold value, and the controllable current path has a low resistance, when the level of the output voltage (Voutmain) of the charge pump is above the threshold value, and wherein the threshold value is the sum of a threshold voltage of the transistor and a level of the control voltage (Voutref) generated by the other charge pump. - an output terminal to provide the output voltage (Voutmain), - a charge pump to generate the output voltage (Voutmain) as a function of an input supply voltage (Vsup), and - a control circuit to limit a level of the output voltage (Voutmain), wherein the control circuit comprises a current branch having a variable resistance, wherein the current branch is arranged between the output terminal and a ground potential, wherein the control circuit comprises a transistor to provide a controllable current path having the variable resistance, wherein the transistor is arranged in the current branch, characterized in that the control circuit comprises another charge pump to generate a control voltage (Voutref) as a function of a reference voltage (Vref), wherein the level of the output voltage (Voutmain) is controlled by the control voltage (Voutref) such that the output voltage (Voutmain) does not exceed a threshold value, wherein the transistor comprises a control terminal to apply the control voltage (Voutref) to control the variable resistance of the controllable current path, wherein the transistor is configured to be operated such that the controllable current path has a high resistance, when the level of the output voltage (Voutmain) of the charge pump is below the threshold value, and the controllable current path has a low resistance, when the level of the output voltage (Voutmain) of the charge pump is above the threshold value, and wherein the threshold value is the sum of a threshold voltage of the transistor and a level of the control voltage (Voutref) generated by the other charge pump.