An electric circuit includes a circuit path from a first reference voltage to a second reference voltage lower than the first reference voltage. The path includes a current generator, a capacitor, a first switching element suitable for connecting or disconnecting the capacitor with respect to the current generator. The first switching element has a triggering value and the electric circuit includes a second switching element placed in parallel to the capacitor and control elements suitable for acting on the first and second switching elements for controlling the charging and discharging of the capacitor. The control elements comprise a comparator operable during the charging of the capacitor and suitable for acting on the first switching element for blocking the charging of the capacitor when the voltage value at its terminals reaches a threshold voltage value. The threshold voltage value is lower than the triggering voltage of the first switching element and higher than the second reference voltage.