An analog indication type electronic timepiece includes a power generation device for transforming kinetic energy produced by motions of a user into electric energy and for causing the electric energy to output from a magnetic coil as an electric charging energy; a secondary power source charged by said electric charging energy; a timepiece circuit driven by a charged energy from said secondary power source to output motor drive pulses; and a drive motor including a drive coil and a drive rotor rotatably driven when the drive coil is energized by said motor drive pulses. This analog indication type electronic timepiece further includes an anti-overcharging device forming a bypass circuit for causing said electric charging energy to bypass relative to said secondary power source when the voltage at said secondary power source reaches a predetermined level, thereby preventing the overcharging to the secondary power source; and a current limiting device for forcedly limiting the bypass current flowing through said bypass circuit when the motor drive pulses are being output from said timepiece circuit, whereby an accurate analog time indication can be made while preventing a malfunction in the drive motor during the anti-overcharging operation to the secondary power source.
The power generator (1) powers an instrument of small volume and is driven, via a gear train, by an oscillating weight (2), said train including a plurality of wheels and pinions (18, 4, 6, 19) arranged in a chain (3). The chain includes a sliding wheel and pinion (4) arranged to disengage from at least one of the other wheel and pinions (18) when the weight (2) is subjected to an acceleration substantially exceeding that occurring during normal use of the instrument.
A reliable power supply control function in a portable electronic device which includes a limiter circuit, or includes the limiter circuit and a voltage step-up circuit, to reduce power consumption. It is detected whether or not a voltage generated by a power generator 40 or a voltage accumulated in a power supply device 48, 80 exceeds a preset limiter-ON voltage. When the voltage generated by the power generator 40 or the voltage accumulated in the power supply device 48, 80 has become not lower than the preset limiter-ON voltage, a voltage of electrical energy supplied to the power supply device is limited to a predetermined reference voltage set in advance. When it is determined based on a detection result of a status-of-power-generation detecting section 91 that power is not generated by the power generator 40, detecting operation of a limiter-ON-voltage detecting circuit 91A is prohibited. Power consumption required for operating the limiter-ON-voltage detecting circuit can be thus reduced.
A portable electronic apparatus and a control method for an electronic apparatus that detects the power-generating state of a power generating unit in a power-saving mode and to positively switch to a normal operation mode. The power-generation voltage of a power generating unit is detected in a power-generation-voltage detection process (steps S2 and S12), and the operation mode of a unit to be driven is switched between a normal operation mode and a power-saving mode according to the power-generating state of the power generating unit or according to the manipulation state of manipulation means in an operation-mode control process (steps S3 to S7, and S10 to S15). In a limiter control process (step S8), the operation of a limiter is disabled when the operation mode of the unit to be driven is the power-saving mode. As a result, it is possible in the power-saving mode that the power-generating state of the power generating unit is detected and the operation mode is positively switched to the normal operation mode in the power-generation-voltage detection process. In a limiter-operation disablement release process (step S13), the limiter is again operated after the operation mode is switched to the normal operation mode.
With respect to a generator (20), a storage device (22) for storing electrical energy output from the generator and a bypass circuit (31) are connected in parallel with each other. A bypass circuit switch (33) of this bypass circuit (31) is controlled on and off according to the voltage of the storage device (22). This makes it possible to reduce the input current into the storage device so as to implement a reduction in the voltage of the storage device, thereby preventing overcharging. Moreover, since a generated waveform corresponding to the rotation period of the generator can be obtained, the rotation period of the generator can be controlled highly precisely and reliably based on this generated waveform, thereby implementing the indication of the correct time.
An electronic timepiece comprises power generation means for generating electricity by using external energy, storage means for storing electric energy received from the power generation means, time-indicating means powered by electric energy supplied from the power generation means or the storage means for indicating time, a switch circuit including a plurality of switching devices and adapted to transfer or intercept electric energy between the power generation means and the storage means and between the power generation means and the time-indicating means, voltage measuring means for measuring voltage across the time-indicating means, and control means that selects one of predetermined power ratios based on the results of measurement by the voltage measuring means and controls the switch circuit according to the selected ratio when the power generation means charges the storage means and the time-indicating means.
