Charging control circuit in in-vehicle charging connector, in-vehicle charging connector, and in-vehicle data-transfer/charging system for external device

A charging control circuit of an in-vehicle charging connector, connected to a main power supply for a vehicle, connecting an in-vehicle apparatus with a charging-target external apparatus, and enabling data-transfer between the in-vehicle apparatus and the external apparatus, the charging control circuit comprising:

• a DC-to-DC converter, to which a battery voltage input from the main power supply or a bus voltage input from the in-vehicle apparatus is supplied, which converts the supplied voltage to a predetermined voltage;
• an output controller that controls the data-transfer between the in-vehicle apparatus and the external apparatus, and determines a charging current for the external apparatus;
• and
• an instantaneous interruption measurement circuit that prevents an instantaneous interruption of the data-transfer between the in-vehicle apparatus and the external apparatus when the battery voltage drops to less than the predetermined voltage,
• wherein the instantaneous interruption measurement circuit includes
• a first switch that switches between supply and cut-off from the bus voltage to the DC-to-DC converter according to the battery voltage,
• a correction resistor that is connected between an output terminal connected to the external apparatus and the output controller, and that limits an output current flowing to the output terminal, and
• a second switch, which is connected in parallel with the correction resistor and connected in series with the first switch, which causes a current to flow to the correction resistor during a period when the bus voltage is being supplied to the DC-to-DC converter.