| 摘要 |
<p>An electronic timepiece in which a stepping motor is controlled by pulse width modulation, using a power source comprising a solar cell and an electric double-layer capacitor, whose output voltage may fluctuate. The stepping motor is driven by pulses from a plurality of pulse generators, each producing pulses of a different width. The fluctuating output from the power source is detected, and depending on the output voltage, one out of the generators is selected to minimize the current of pulses that flows to drive the stepping motor. Accordingly, the stepping motor is always driven with the minimum necessary current, resulting in efficient use of the power source. <IMAGE></p> |
