To detect reduction in a power supply voltage without arranging a dedicated circuit for detecting a voltage such as a comparator circuit.
A controller controls the driving of a stepping motor 109 by selecting any of a plurality of main driving pulses P1 having different driving energy from one another or a compensation driving pulses P2 having energy larger than that of the main driving pulses P1, according to rotation status detected by a rotation detector. The controller also determines that the voltage of a battery 112 is reduced to a value lower than a predetermined value, if the rotation detector detects a driving energy shortage when the stepping motor 109 is driven with a predetermined driving pulse such as a main driving pulse P1max having maximum driving energy.
| JPS55142269 | ELECTRONIC TIMEPIECE |
| JPS583773 | [Title of the device] Two rotor type stepping motor |
Noriaki Uchino
Nobuyuki Kimura