Microcircuit chip card with contact and contactless operating modes

Microcircuit mounted on a portable support with two operating modes, contact or contactless, comprising :

• communication means (2) specific to the contactless operating mode, communication means (3) specific to the contact operating mode, and electronic means (4) common to the two operating modes,
• a coil (L) for receiving an alternating voltage (Va) by induction,
• a circuit (Pd) which rectifies said alternating voltage (Va) for producing a first supply voltage (Vcc1) of the microcircuit,
• at least a supply contact (p1) for receiving a second supply voltage (Vcc2) of the microcircuit,
• a line (5) for distributing the first (Vcc1) or second (Vcc2) supply voltage,
• a switching means (6, 13) arranged between the supply contact (p1) and the distribution line (5), and
• means (7, 8, 20, 21, 30, 40) for controlling the switching means,
• characterised in that the means for controlling the switching means comprise:
• detection means (8, 30, 40) designed to detect the presence of the alternating voltage (Va) on the terminals of the coil (L) and provide a control signal (CTL) distinct from the first supply voltage (Vcc1), the control signal (CTL) having a first value when the alternating voltage (Va) is not detected and a second value when the alternating voltage (Va) is detected, and
• means (7, 20, 21) for closing and opening the switching means (6, 13), designed to close the switching means when the second supply voltage (Vcc2) is present and the control signal (CTL) has said first value, and to open in priority the switching means when the control signal has said second value.