According to one embodiment, when the circuit CTRL detects that the voltage V_T is between the threshold Vth and Vth_l, the circuit CTRL is configured to send a request to the load 400 (FIG. 1) coupled to the interface 214, via the communication terminals CC1 and CC2, to swap, if possible, the role (load or source) of the devices 200 and 400. Indeed, devices 200 and 400 can have the ability to exchange their power roles when they are of the type DRP (Dual Role Power). Preferably, the request is of the FRS (Fast Request Swap) type, which is defined in the USB Power Delivery Specification Revision 3.0. An FRS request can be sent only if the devices 200 and 400 have previously agreed that FRS is supported.

According to one embodiment, the circuit CTRL is further configured to compare the voltage V_T to a threshold Vth_h, when the voltage V_T has a steady value representative of the voltage V_P. The threshold Vth_h is determined by the nominal value of the voltage V_AC and is, in absolute values, higher than the threshold Vth_l.

The threshold Vth_h is determined so that, when the voltage V_T has a steady value representative of the value of the voltage V_P, the voltage V_T is, in absolutes values, above the threshold Vth_h if the value of the voltage V_P is above its nominal value. A value of voltage V_P above its nominal value indicates an issue on the mains, and more particularly, that the voltage V_AC has a value above its nominal value.