Abstract: The invention relates to a voltage generating circuit having: a voltage input (1); voltage boosting means (2), having an input (3) and an output (4); means (6) for varying the voltage supply level of the input to the said boosting means (2) from the said voltage input of the circuit, capable, on one hand, in a first state, of permitting the application, at the input to the said boosting means (2), of a fraction, that is possibly limited, of the voltage input to the circuit and, in a second state, of increasing the level of voltage applied to the said input to the boosting means (2) and, on the other hand, of permitting the change-over from the said first to the said second state according to a triggering signal, obtained by feedback of the output voltage from the said boosting means (2) to the said means (6) for varying the voltage level, so as to optimize the production at the output from the said boosting means (2) of a desired voltage level.