摘要 |
A power source device is provided which is capable of charging a secondary cell in a stable manner even in an environment in which power generated by a solar cell varies due to changes in sunlight intensity and/or ambient temperatures. By power generated by a solar cell module, an electric double-layer capacitor is charged and, by using a charging voltage of the electric double-layer capacitor, a booster-type DC-DC (Direct Current-Direct Current) converter is driven. A charge on/off controlling circuit detects the voltage of the electric double-layer capacitor and, when the voltage exceeds a high level threshold voltage, keeps a charge controlling signal (output signal from a terminal) in an active mode and performs a charge starting operation and, after that, when the voltage of the electric double-layer capacitor reaches a low level threshold value, holds the charge controlling signal in a non-active mode and performs a charge stopping operation.
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