| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress degradation of a secondary battery which is caused by overcharging, with no voltage detection special circuit such as a comparator circuit. <P>SOLUTION: There are at least provided a secondary battery 111 which acts as a power source for supplying power to a stepping motor 108, a rotation detecting circuit 109 which detects rotational state of the stepping motor 108, control means which selects a drive pulse of the energy corresponding to the rotational state of the stepping motor 108 out of a plurality of kinds of drive pulses, for driving, and a solar cell 112 which charges the secondary battery 111. The control means, if determines that the stepping motor 108 can be rotated with an overcharge command drive pulse Pkj of predetermined energy, makes change to an excessive consumption drive pulse Pks whose energy is larger than the overcharge command drive pulse Pkj, for driving. <P>COPYRIGHT: (C)2012,JPO&INPIT |
