Short circuit protection for data interface charging

A system, comprising:

• a flyback converter including a transformer having a primary side and a second side, the flyback converter having a primary-side controller configured to regulate a switching of a primary-side power switch to power a load device through a power supply voltage carried on a power supply voltage pin in an USB data interface that includes a data signal carried on a pair of data pins separate from the power supply terminal;
• a secondary-side fast charge interface configured to enumerate the load device using the data signal to determine whether the load device supports an increased output voltage level that is greater than a default level for the output voltage, and wherein the secondary-side fast charge interface is configured to signal the primary-side controller to increase the power supply voltage to the increased output voltage level;
• and
• a secondary-side overvoltage protection circuit including a comparator configured to compare a voltage for the data signal to a reference voltage to assert an overvoltage alarm signal to the primary-side controller responsive to the voltage for the data signal being greater than the reference voltage, wherein the primary-side controller is configured to reduce the power supply voltage to the default level responsive to an assertion of the overvoltage alarm signal.