Stabilising the contactless power supply of the chip of a chip card and corresponding chip card

A method which is implemented by a chip of a chip card for adjusting the internal supply voltage of the chip based on the field strength of an external electromagnetic field supplying the chip with power,

• wherein the internal supply voltage is reducible through activation and deactivation of a threshold voltage reduction, and the chip has a sensor register indicating a field strength value which is dependent on the external field strength and the adjusted internal supply voltage,
• wherein the method comprises the following steps:
• a step A, comprising activating the threshold voltage reduction for the first time when the field strength value in the sensor register is less than a predetermined first switching threshold;
• a step B, comprising deactivating the threshold voltage reduction for the first time as soon as the field strength value in the sensor register is greater than or equal to the first switching threshold;
• and
• a step C, comprising setting a predetermined second switching threshold for each further activation of the threshold voltage reduction while retaining the first switching threshold for each further deactivation of the threshold voltage reduction, wherein the second switching threshold is lower than the first switching threshold.