Patent ID: 6075402
Filing Date: 2000-06-13
Classification: H02M

Abstract:
Charge pump comprising a plurality of stages connected in series, an input terminal of the charge pump being connected to a voltage supply and an output terminal of the charge pump providing an output voltage higher than the voltage supply, each stage comprising unidirectional current flow MOS transistor means connected between a stage input terminal and a stage output terminal allowing current to flow only from said stage input terminal to said stage output terminal, and a first capacitor having one plate connected to said stage output terminal and another plate driven by a respective first digital signal that periodically switches between ground and said voltage supply,wherein the unidirectional current flow MOS transistor means of the stages have independent bulk electrodes,wherein a bias voltage generator circuit is provided for biasing the bulk electrodes of said unidirectional current flow MOS transistor means at respective bulk potentials which become progressively higher going from the stages proximate to said input terminal to the stages proximate to said output terminal of the charge pump,wherein said bulk potentials are lower or higher than said voltage supply, and wherein each of said bulk potentials is at most equal to the minimum between a source voltage and a drain voltage of the respective unidirectional current flow MOS transistor means; andwherein said bias voltage generator circuit generates said bulk potentials starting from the output voltage of the charge pump.