JPS603578A - Timepiece provided with solar battery - Google Patents

Abstract

PURPOSE:To inform exactly a full charging time point to a timepiece bearer, and to shorten a time required for a charging action by providing an informing means of a charging completion to a secondary power source. CONSTITUTION:A solar battery 1 is connected to a timepiece load 3 through a reverse-current stopping diode 6. When an intensity of illumination rises and an induced voltage of the solar battery 1 rises, the timepiece load 3 is driven. When the voltage further rises, a high capacity capacitor 2 is charged by a charging circuit 4. A voltage detecting circuit 7 decides that a terminal voltage of the high capacity capacitor 2 has reached the rated voltage by a charging current, and turns on a transistor 8 for driving a light emitting diode 9 through a control resistance 10. When the induced voltage further rises, a circuit voltage is held in the maximum rated voltage by a constant-voltage holding circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a charging completion notification circuit for a solar cell watch.

Until now, there have been no known solar battery watches equipped with a charging completion notification circuit.Recently, with the aim of creating long-life watches, solar batteries have been used as a secondary power source to provide better charging/discharging characteristics and reliability than secondary batteries. Electric double-layer capacitors are currently commercially available as high-capacity capacitors, but with current technology, the capacitance of a secondary battery is small enough to be mounted in a wristwatch. The duration of the discharge as a clock is about several tens of hours to several days. This short duration should be covered by charging from the solar battery, but charging itself must wait for the wristwatch wearer to perform a charging action based on his free will. Originally, some solar-powered wristwatches equipped with secondary batteries were equipped with an insufficient charge warning circuit to notify the voltage drop of the secondary battery, but electric double layer capacitors with short discharge durations are It is thought that the charging N1 request probability will increase, and it has become necessary to make the act of charging itself even more impressive.

In addition, although it takes several minutes to fully charge this capacitor under direct sunlight, the charging time increases as the illuminance decreases. Charging under illuminance other than direct sunlight takes a long time, and the wearer of the watch cannot tell when charging is complete, and the lack of charge warning alone is insufficient.

The present invention eliminates this drawback, and its purpose is to accurately notify the watch wearer that the backup capacity of the secondary power source of the solar battery has reached its maximum.

The present invention will be described in detail below based on Examples.

FIG. 1 shows an embodiment of a charging completion notification circuit that lights up the issuing diode 9, and FIG. 2 shows an example of a charging completion notification circuit that drives the piezoelectric element 16 as a sounding body. In the figure, a solar cell 1 is connected to a clock load 3 via a backflow blocking diode 6. When the illuminance increases and the induced voltage of the solar cell 1 increases, the clock load 3 is driven. When the voltage further increases, the high capacity fundaca 2 is charged by the charging circuit 4. The voltage detection circuit 7 determines that the terminal voltage of the high capacity capacitor 2 has reached the rated voltage due to the charging current, and turns on the transistor 8 that drives the light emitting diode 9 via the limiting resistor 10. When the induced voltage further increases, the circuit voltage is maintained at the maximum rated voltage by the constant voltage holding circuit 15. In Figure 2, when the terminal voltage of the high capacity capacitor 2 reaches the rated voltage, A
There is an output to ND gate 11, 4KH from the clock circuit
According to the AND condition with the z signal 12, the transistor 8 that drives the piezoelectric element 16 with the resonant coil 14 is turned on. Furthermore, under low illumination with no induced voltage, the charge accumulated in the high capacity capacitor 2 is supplied to the timepiece load 6 through the discharge circuit 5.

As described above, the present invention provides a solar cell watch with means for notifying the completion of charging to a secondary power source, thereby accurately informing the wearer of the watch when it is fully charged, and minimizing the time required for charging. , we can provide the best product as a solar battery watch, reducing the burden on humans as much as possible.

It should be noted that with the current digital technology, it is easy to think of applications such as a melody-driven device (with a ring stopper) as a notification device when charging is complete, and it is thought that a rich variety of solar cell-equipped watches will be realized.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the invention, and FIG. 2 is a circuit diagram showing a second embodiment of the invention. 1...Solar cell 2...High capacity capacitor 3...
Clock load 4...Charging circuit 5...Discharging circuit 6...Diode 7 voltage detection circuit 8...Transistor 9...Light emitting diode 1
0...Resistance 1l-=AND gate 12=4KHz signal 13...Piezoelectric element 14...Resonance coil 15...
- Constant voltage holding circuit and above Applicant: Suwa Seikosha Co., Ltd. Patent attorney Mogami Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A solar cell watch having at least a solar cell, a high-capacity capacitor, and means for charging the high-capacity capacitor, characterized in that a circuit is provided to notify completion of charging of the high-capacity capacitor. A solar battery clock. 2. The solar cell watch according to claim 1, further comprising an optical display element as a circuit for notifying the completion of charging. 3. The solar cell timepiece according to claim 1, further comprising a sounding body drive circuit as a circuit for notifying the completion of charging. 4. The solar cell watch according to claim 1, further comprising a secondary battery as the high-capacity capacitor.