1. A method for generating an adjustable bandgap reference voltage, comprising: generating a current proportional to absolute temperature, by equalizing a voltage across terminals of a core, the core configured to then be traversed by the current proportional to absolute temperature; generating a current inversely proportional to absolute temperature; summing the current proportional to absolute temperature and the current inversely proportional to absolute temperature; and generating the bandgap reference voltage on the basis of the sum of currents, wherein the equalizing comprises connecting a first fed-back amplifier across the terminals of the core, the first fed-back amplifier having a first stage comprising first PMOS transistors having conduction paths between the terminals of the core and a reference terminal and having a common-gate connection, the equalizing further comprising biasing the first stage on the basis of the current inversely proportional to absolute temperature; wherein the summing is performed in a feedback stage of the first fed-back amplifier; wherein the current inversely proportional to absolute temperature is generated by using a second fed-back amplifier having a first stage having a part common with the first stage of the first fed-back amplifier and wherein the first stage of the second fed-back amplifier is also biased on the basis of the current inversely proportional to absolute temperature; and wherein the first stage of the first fed-back amplifier and the first stage of the second fed-back amplifier are biased with the current inversely proportional to absolute temperature or with a fraction of the current inversely proportional to absolute temperature.