Host device and terminal device, and communication system

摘要

A host-side control unit 120 receives a terminal-device-side notification value INFD indicating a second voltage V2 that is a voltage at a reference point P2 on a terminal-device-side power supply line 134 from a terminal device 130, calculates a first resistance value R1 indicating a resistance from a power supply unit 112 to the reference point P2 based on the terminal-device-side notification value INFD, a first voltage V1 output by the power supply unit 112, and a first current A1 measured by a first current measurement unit 116, and supplies the calculated first resistance value R1 to the power supply unit 112. The power supply unit 112 adjusts the first voltage V1 according to the first resistance value R1 and the first current value A1 measured by the first current measurement unit 116 at that moment so that the second voltage V2 falls within a predetermined first reference range.

主权项

1. A host device that supplies electric power to a terminal device, comprising:
a host-side connector; a power supply unit configured to output a first voltage; a host-side power supply line connecting the power supply unit to the host-side connector; a first current measurement unit configured to measure a first current flowing through the host-side power supply line; and a host-side control unit configured to:
receive, from the terminal device, a terminal-device-side notification value including a value of a second voltage at a reference point on a terminal-device-side power supply line or a value that enables the second voltage to be calculated,calculate a first resistance value indicating a resistance from the power supply unit to the reference point on the terminal-device-side power supply line based on the terminal-device-side notification value, a value of the first voltage and a value of the first current, andoutput the calculated first resistance value to the power supply unit, wherein, when the second voltage is outside of a predetermined first reference range associated with the reference point on the terminal-device-side power supply line, the power supply unit is further configured to adjust the first voltage according to the first resistance value supplied from the host-side control unit and the first current value measured by the first current measurement unit such that the second voltage changes to a value within the predetermined first reference range, wherein when the second voltage is greater than the predetermined first reference range, the power supply unit is configured to reduce the first voltage such that the second voltage decreases to a value within the predetermined first reference range, and when the second voltage is less than the predetermined first reference range, the power supply unit is configured to increase the first voltage such that the second voltage increases to a value within the predetermined first reference range.