A device for converting a continuous supply voltage into a continuous output voltage includes at least one inductor accumulating energy during an accumulation time and delivering said accumulated energy during a discharge time, so that said output voltage has a value that is greater than or equal to that of said supply voltage. An oscillator controls said accumulation and discharge times, in which a period is equal to a sum of said accumulation time and said discharge time and a cyclic ratio is equal to the ratio of said accumulation time to said period. The oscillator includes a mechanism for controlling said period and said cyclic ratio according to said supply voltage and said output voltage.