Power supply device using solar cell, electronic apparatus such as communication apparatus equipped with the same, and signboard apparatus

A power supply device that supplies electric power generated by a solar cell to a load, the power supply device comprising:

• a solar cell module including a plurality of dye-sensitized solar cells that are electrically connected in series;
• and
• an output control circuit that supplies the electric power generated by the solar cell module to the load when an output voltage of the solar cell module increases and reaches a predetermined first voltage V1, and that interrupts the supplying of the electric power generated by the solar cell module to the load when the output voltage of the solar cell module decreases and reaches a predetermined second voltage V2,
• wherein the second voltage V2 is lower than the first voltage V1 and satisfies an inequality expression indicated below:
• V2≥0.12×N [V]
• where N denotes the number of dye-sensitized solar cells connected in series in the solar cell module.

An output control method for controlling supplying of electric power to a load in a power supply device that includes a solar cell module including a plurality of solar cells electrically connected in series, the output control method comprising:

• a step for supplying the electric power generated by the solar cell module to the load when an output voltage of the solar cell module increases and reaches a predetermined first voltage V1;
• and
• a step for interrupting the supplying of the electric power generated by the solar cell module to the load when the output voltage of the solar cell module decreases and reaches a predetermined second voltage V2,
• wherein the second voltage V2 is lower than the first voltage V1 and is higher than a second highest output voltage of output voltages of the solar cell module corresponding to inflection points in a current-voltage characteristic of the solar cell module.