Electricity: motive power systems – Open-loop stepping motor control systems
Reexamination Certificate
2001-01-18
2002-11-05
Ro, Bentsu (Department: 2837)
Electricity: motive power systems
Open-loop stepping motor control systems
C318S685000, C368S204000, C368S218000
Reexamination Certificate
active
06476580
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an electronic apparatus and a control method therefor, and more preferably, to an electronic apparatus, such as a portable electronic timepiece apparatus, having a built-in storage device and a drive motor, and to a control method for such an electronic apparatus.
BACKGROUND ART
Recently, small electronic timepieces, such as watches, which have a built-in generator device, such as a solar cell, and which can be operated without the need for replacing batteries have been implemented. These electronic timepieces are provided with a function of temporarily charging power generated in the generator device into, for example, a large-capacitance capacitor, and when power is not being generated, time is indicated by the power discharged from the capacitor. Accordingly, such electronic timepieces can be stably operated for a long time without batteries, and considering the effort required to replace batteries and the problem of disposing of them, it can be expected that many electronic timepieces will have a built-in generator device.
As such an electronic timepiece having a built-in generator device, there is an electronic timepiece with a generator device disclosed in International Patent Publication No. WO98/41906.
In this electronic timepiece with a generator device, the presence or the absence of power generation is detected when the rotation of the motor is to be detected. When power generation is detected, correcting driving pulses are output regardless of the detection result of the rotation of the motor, thereby ensuring the reliable rotation of the motor.
The above-described example of related art presents the following problems. The presence or the absence of power generation is detected when the rotation of the motor is to be detected. Accordingly, if power has been continuously generated before the rotation of the motor is detected, the power of normal motor-driving pulses are wasted since correcting driving pulses are output after the normal motor-driving pulses have been output.
Additionally, a power-generation operation detection circuit is provided at the stage subsequent to a rectifier circuit. This means that the power-generation operation detection circuit is provided in a charging path to a secondary power supply. Accordingly, in detecting power generation, charging must be interrupted, thereby lowering the charging efficiency.
Moreover, the amount of generation power which causes a malfunction of the motor is preset by measurements. Thus, every time the mechanical structure of the generator or the motor is changed, the amount of generation power, which can be used as a reference, has to be set by measurements.
Further, since the charging current varies according to the stored voltage of the secondary power supply, an AC magnetic field generated by the generator device is different according to the stored voltage of the secondary power supply.
In the above-described example of related art, the charging path to the secondary power supply is interrupted when power generation is detected. Accordingly, when the stored voltage of the secondary power supply is high, namely, when the AC magnetic field is not easily generated since the charging current is prevented from flowing into the secondary power supply, correcting driving pulses are disadvantageously output although the motor can be driven under normal conditions. As a result, power is wasted.
Additionally, in the above-described example of related art, when an overcharge-prevention circuit for preventing the overcharging of the secondary power supply is operated, the detection result of the power-generation operation detection circuit is fixed in the generating state. Thus, even when the generator device is not generating power so that an AC magnetic field is not generated from the generator device, and even when the motor can be driven under normal conditions, correcting driving pulses are disadvantageously output, thereby wasting power.
Accordingly, it is an object of the present invention to provide an electronic apparatus and a control method therefor in which wasteful power consumption can be reduced and the charging efficiency is not lowered by reliably driving a motor of the electronic apparatus having a generator, and in which the power-generation state can be detected without being influenced by a change in the configuration of the generator or the motor.
SUMMARY OF THE INVENTION
A first aspect of the present invention is characterized by including: a power generating unit for generating power; a storage unit for storing the generated electric energy; a single or a plurality of motors driven by the electric energy stored by the storage unit; a pulse driving control unit for controlling the driving of the motor by outputting a normal driving-pulse signal; a power-generation magnetic-field detection unit for detecting whether a magnetic field is generated by the power generation; and a correcting-driving-pulse output unit for outputting a correcting driving-pulse signal having an effective power larger than the normal driving-pulse signal to the motor when it is detected by the power-generation magnetic-field detection unit that the magnetic field is generated by the power generation. The power-generation magnetic-field detection unit includes a charging-state determining unit for making a determination by assuming that the magnetic field is generated by the power generation when a charging current flows into the storage unit by the power generation of the power generating unit.
A second aspect of the present invention is characterized by including: a power generating unit for generating power; a storage unit for storing the generated electric energy; a single or a plurality of motors driven by the electric energy stored by the storage unit; a pulse driving control unit for controlling the driving of the motor by outputting a normal driving-pulse signal; a power-generation magnetic-field detection unit for detecting whether a magnetic field is generated by the power generation; and a correcting-driving-pulse output unit for outputting a correcting driving-pulse signal having an effective power larger than the normal driving-pulse signal to the motor when it is detected by the power-generation magnetic-field detection unit that the magnetic field is generated by the power generation. The power-generation magnetic-field detection unit includes an overcharging-prevention-current generation determining unit for making a determination by assuming that the magnetic field is generated by the power generation according to an overcharging-prevention current flowing into the power generating unit when the storage unit is in an overcharging-prevention state.
A third aspect of the present invention according to the first aspect of the present invention or the second aspect of the present invention is characterized in that the power-generation magnetic-field detection unit includes a generation-current determining unit for determining whether a value of a generation current output from the power generating unit exceeds a predetermined generation current value.
A fourth aspect of the present invention according to the first aspect of the present invention or the second aspect of the present invention is characterized in that the power-generation magnetic-field detection unit includes a stored-voltage determining unit for calculating a stored voltage of the storage unit based on a generation current output from the power generating unit and for determining whether the stored voltage exceeds a predetermined reference stored voltage.
A fifth aspect of the present invention according to the first aspect of the present invention or the second aspect of the present invention is characterized in that the power generating unit includes a pair of output terminals, and there are provided a comparison unit for outputting a comparison result signal by comparing a voltage of the output terminals of the power generating unit with a predetermined voltage corresponding to a terminal volt
Fujisawa Teruhiko
Iida Kenji
Iijima Yoshitaka
Nakamiya Shinji
Martin Edgardo San
Ro Bentsu
Seiko Epson Corporation
Watson Mark P.
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