A protection circuit comprising: a first USB VBUS terminal configured to couple to an USB VBUS terminal of a first controller, at least a first USB data terminal (2a, 3a) configured to couple to an USB data terminal of a first controller, a second USB VBUS terminal configured to couple to an USB VBUS terminal of a second controller, at least a second USB data terminal (2b, 3b) configured to couple to an USB data terminal of a second controller, a VBUS line electrically coupling the first USB VBUS terminal and the second USB VBUS terminal, at least a data line electrically coupling the at least a first USB data terminal (2a, 3a) and the at least a second USB data terminal (2b, 3b), at least an interrupter (15a - 17b) arranged in the VBUS line or in the at least a data line, wherein operation of the at least an interrupter (15a - 17b) electrically interrupts the VBUS line or the at least a data line, a control circuit with a switch, the control circuit being electrically connected to the first USB VBUS terminal and controlling via the switch the at least an interrupter (15a - 17b), wherein the switch is operable to generate an interrupt signal to cause operation of the at least an interrupter (15a - 17b), wherein the control circuit comprises first branch (35 - 38, 1a) with a breakdown member defining a first threshold voltage, a second branch (35, 40, 42, 43, 1a) with a first comparison member (40, 42) configured to compare a voltage at the first USB VBUS terminal to a second threshold, the two branches connecting to the first USB VBUS terminal, and a third branch (6, 41, 39, 43, 35); wherein the breakdown member connects directly to the first USB VBUS terminal and the same switch will generate an interrupt signal, if - a voltage at the first USB VBUS terminal causes a voltage drop over the breakdown member exceeding the first threshold voltage, or if - a voltage at the first USB VBUS terminal causes a voltage applied to the first comparison member (40, 42) that is less than the second threshold; wherein the third branch (6, 41, 39, 43, 35) directly connects the first comparison member (40, 42) to the switch of the first branch (35 - 38, 1a) having the breakdown member. a first USB VBUS terminal configured to couple to an USB VBUS terminal of a first controller, at least a first USB data terminal (2a, 3a) configured to couple to an USB data terminal of a first controller, a second USB VBUS terminal configured to couple to an USB VBUS terminal of a second controller, at least a second USB data terminal (2b, 3b) configured to couple to an USB data terminal of a second controller, a VBUS line electrically coupling the first USB VBUS terminal and the second USB VBUS terminal, at least a data line electrically coupling the at least a first USB data terminal (2a, 3a) and the at least a second USB data terminal (2b, 3b), at least an interrupter (15a - 17b) arranged in the VBUS line or in the at least a data line, wherein operation of the at least an interrupter (15a - 17b) electrically interrupts the VBUS line or the at least a data line, a control circuit with a switch, the control circuit being electrically connected to the first USB VBUS terminal and controlling via the switch the at least an interrupter (15a - 17b), wherein the switch is operable to generate an interrupt signal to cause operation of the at least an interrupter (15a - 17b), wherein the control circuit comprises first branch (35 - 38, 1a) with a breakdown member defining a first threshold voltage, a second branch (35, 40, 42, 43, 1a) with a first comparison member (40, 42) configured to compare a voltage at the first USB VBUS terminal to a second threshold, the two branches connecting to the first USB VBUS terminal, and a third branch (6, 41, 39, 43, 35); wherein the breakdown member connects directly to the first USB VBUS terminal and the same switch will generate an interrupt signal, if - a voltage at the first USB VBUS terminal causes a voltage drop over the breakdown member exceeding the first threshold voltage, or if - a voltage at the first USB VBUS terminal causes a voltage applied to the first comparison member (40, 42) that is less than the second threshold; - a voltage at the first USB VBUS terminal causes a voltage drop over the breakdown member exceeding the first threshold voltage, or if - a voltage at the first USB VBUS terminal causes a voltage applied to the first comparison member (40, 42) that is less than the second threshold; wherein the third branch (6, 41, 39, 43, 35) directly connects the first comparison member (40, 42) to the switch of the first branch (35 - 38, 1a) having the breakdown member.