| 摘要 |
PURPOSE:To prolong the lasting time before a timepiece is stopped when a power source with reduced capacity was used, by providing a plurality of power sources and making it possible to charge the power source with reduced electric energy by the other power source. CONSTITUTION:Power generated by irradiating a solar battery 1 with light is charged to an electric double layer condenser 4 through a reverse-current preventing diode 3. At this time, when the generated electro motive voltage VSS1 of a battery 1 comes to rated voltage or more, a limiter circuit 2 is operated to stop the charging to the condenser 4. The power charged in the condenser 4 receives optimum boosting by a multistage boosting charge circuit 5 to charge a condenser 6. The condenser 6 functions as the power source of a voltage detection circuit 7 for detecting the voltage VSS1 of the condenser 4, a control circuit 8 for allowing the circuit 5 to perform optimum boosting charging on the basis of voltage detection output and a stepping motor driving circuit 9. The circuit 9 stepwise control a driving pulse width on the basis of the voltage of the condenser 6 to minimize the consumption current for driving a stepping motor 10. |
