Citizen Watch Company, Ltd.

Citizen Holdings Company, Ltd.

Motoki Funahashi

Akiyoshi Murakami

Haruhiko Higuchi

Kenji Fujita

Yoichi Nagata

Masahiko Hitomi

The invention provides a rechargeable electronic timepiece that restarts the operation of a clock circuit by inputting a power source, thereby securely confirming the clock operation. The electronic timepiece includes a first power source (), a clock circuit () connected to the first power source, a power source input detecting circuit () for detecting an input of a second power source (), a switch circuit () for connecting the first power source and the second power source, and a control circuit () for controlling the switch circuit to connect the first power source and the second power source so that the first power source is charged by the second power source thereby operating the clock circuit when the power source input detecting circuit detects an input of the second power source.

Electronic clock

When a stem switch () is pulled out, a switch signal forming unitoutputs a signal (RS) indicating that effect, a control unit () receives the signal (RS) and starts clocking by a timer (). The control unit () receives a signal (HS) output from an electricity-generation detecting unit () within the clocking period, detects the electricity generating operation of an electricity generating unit (), and outputs a signal (CS) indicating that effect. A narrow pulse forming unit () forms a narrow pulse having a width of such a degree that the motor () is not driven based on the signal (CS), and outputs the narrow pulse to a motor driving circuit (). The motor driving circuit () flows a fine current through a coil () which drives the motor () based on the narrow pulse. An external device detects a variation of the narrow pulse, thereby confirming whether electricity is generated.

Electronic timepiece

In detecting power generation of an electronic timepiece having a conventional power generating unit, voltage output by the power generating unit is limited by output from a storage unit since the power generating unit and the storage means are connected when the power generation state is detected, and voltage equal to or larger than voltage output from the storage unit cannot be detected. An electronic timepiece is provided which can overcome the problem and can check an operation of the power generating unit securely irrespective of the state of the storage means. In an electronic timepiece driven by power stored from a power generating unit () into a storage unit (), the electronic timepiece includes a power generation detecting unit () that detects a power generation state of the power generating unit () and a switch unit () that separates the power generating unit () and the storage unit () when the power generation state of the power generating unit () is detected. In this case, the switch () between the power generating unit () and the storage unit () is controlled to OFF so that the output from the power generating unit () cannot be limited by the output from the storage unit ().

Growing community of inventors

Tokyo, Japan

Motoki Funahashi