US Patent 7747807 Host controller including a disconnection detection circuit

A host controller includes a disconnection detection circuit 52 which compares a voltage level of a first differential signal DP of first and second differential signals DP and DM making up a differential signal pair corresponding to a given range in a frame packet with a comparison voltage CV, compares a voltage level of the second differential signal DM corresponding to a given range in the frame packet with the comparison voltage CV, and detects that a host and a device have been disconnected when the voltage level of at least one of the first and second differential signals DP and DM corresponding to the given range is higher than the comparison voltage CV.