Patent ID: 7323927

Claim:
An integrated charge pump, comprising: a pump capacitor having a first terminal and a second terminal; a control unit for operating the charge pump alternately between a first phase and a second phase; a first switching device connected to charge the pump capacitor with a pump voltage in the first phase; and a second switching device configured to pull the potential of the first terminal of the pump capacitor to a predetermined potential in the second phase and to connect the second terminal of the pump capacitor to an output node; wherein the second switching device includes a first transistor connected between the second terminal of the pump capacitor and the output node; wherein a substrate terminal of the first transistor is fixedly connected to the output node; wherein the second switching device pulls the first terminal of the pump capacitor to the predetermined potential with a voltage change gradient, the gradient being selected such that a diode breakdown voltage is not exceeded in the first transistor; wherein the second switching device has a second transistor which connects the first terminal of the pump capacitor to the predetermined potential via a resistance in the second phase; and wherein a channel width of the first transistor is greater than a channel width of the second transistor, wherein a voltage drop across the channel of the first transistor in the second phase remains below the diode breakdown voltage of the first transistor.