| 摘要 |
<p> A conventional electronic watch including a crystal oscillation circuit stops when the crown is pulled to set the watch because a switch is operated. Though the oscillation is retained, the watch remains at rest and consequently a small current consumption is maintained. The watch is stored also in this state. According to the invention, to save power further, a counting circuit is provided to stop crystal oscillation and frequency division after a predetermined time from the time when the crown is pulled, thereby decreasing more the current consumption by the circuit. The pulldown resistor connected to the switch is composed of two parallel transistors (Tr) having different resistances, and only the Tr having the larger resistance is made to conduct by a signal in a power-saving status so as to decrease the current. Alternatively, a circuit which memorizes the power-saving status is provided. In the power-saving status, the Tr of the pulldown resistor is turned off to stop the current. The switch is provided with an intermediate contact to erase the memory by the action of the intermediate contact driven by the push-in of the crown and thereby to allow the Tr to conduct, resulting in returning the watch to a normal operation.</p> |
