| 摘要 |
In the present invention, a main switch circuit (13) is provided between an electric power line (PL), to which voltage outputted from a solar cell (11) is applied, and a battery module (12). A protection circuit (19) turns OFF the main switch circuit (13) to protect the battery module (12) from overcharging when the voltage (VBAT) of the battery module (12) is equal to or greater than an upper limit voltage. The voltage outputted from the solar cell (11) is set so as to be greater than the upper limit voltage to allow the battery module (12) to be charged to the upper limit voltage. When a charge ON command signal has been received, a control unit (18) turns ON only a sub-switch circuit (14) to introduce current from the solar cell (11) into a parallel circuit (15) and to suppress the voltage (VPL) of the power line (PL) to less than the upper limit voltage before turning ON the main switch circuit (13). |
