JPS603577A - Wrist watch provided with solar battery - Google Patents

Abstract

PURPOSE:To prevent a wasteful current loss at the time of non-operation of a titled watch, and to shorten a charging time to come by providing a detecting circuit of a feeding voltage of a solar battery and a detecting circuit of a terminal voltage of a high capacity capacitor, and opening or closing a discharging circuit in accordance with whether its detecting voltage is high or low. CONSTITUTION:A timepiece load 1 is connected to an electric double layer capacitor 3 through a switching element 5. An output 12 of a feeding voltage detecting circuit 9 of a solar battery is outputted when the feeding voltage is in a state of a reference value or below, and an output 11 of a terminal voltage detecting circuit 10 of the electric double layer capacitor 3 is outputted when the terminal voltage is in a state of the reference value or above. When both the input 11 and the input 12 have a signal at an AND gate 13, a switching element 5 is turned on. The reference voltage is set in advance to the minimum operation voltage of the timepiece load 1, and when the capacitor 3 in charged to the minimum operating voltage or above, it is backed up naturally, but in case the discharge has been executed to the minimum operating voltage or below, discharge to the timepiece load 1 is inhibited.

Description

Detailed Description of the Invention The present invention provides discharge control of a high-capacity capacitor during power backup of a long-life electric clock that has a solar cell and stores the output current of the solar cell in a high-capacity capacitor to maintain the movement of the clock. Regarding.

A conventional discharging circuit (charging circuit omitted) is shown in FIG. 1st
In the figure, 1 is the clock load, and (A) is the secondary battery 2.
(A) is a connection via an electric double layer capacitor 3 and a discharge diode 4, and (T) is a connection via a switch element 5.

In (1), 6 is a flip-flop, and 7 is the output from the month carry counter. When the output 8 of the solar cell is not present for 1 to 2 months, the switch element 5 is turned off. In any case, in (a) it is impossible to control the discharge, in (b) there is a loss due to a drop in the forward voltage of diode 4, and in (ii) the output voltage from the solar cell does not reach the set value for a certain period of time. This is a circuit that stops discharging and prevents unnecessary voltage drops, but it predicts the discharge voltage over time based on the discharge characteristics of the secondary battery, and does not detect the true terminal voltage, but rather predicts the discharge voltage based on the secondary battery characteristics. It becomes difficult to set a strict discharge stop voltage due to variations in the voltage. Particularly when an electric double layer capacitor, which has a lower capacity than a secondary battery, is provided as a secondary power source, wasteful discharge after the clock has stopped significantly delays the charging time when restarting the clock.

The present invention eliminates such drawbacks, and aims to improve the clock duration during backup in a solar battery wristwatch equipped with a high-capacity capacitor, and to prevent the drop in discharge voltage as much as possible when the clock is not operating. It is said that

The present invention will be described in detail below based on Examples. Figure 2 shows a discharge circuit according to the present invention (solar cell and charging circuit omitted)
In this embodiment, a watch load 1 is connected to an electric double layer capacitor 6 via a switch element 5. 9 is a solar cell electromotive voltage detection circuit, and its output 12 is output when the electromotive voltage is below a reference value. 10 is a terminal voltage detection circuit of the electric double layer capacitor 3, and its output 11 is output when the terminal voltage is higher than a reference value. 13 is AN
It is a D gate, and turns on the switch element 5 when both inputs 11 and 12 have signals.

The reference voltages at 9 and 10 are set to the minimum operating voltage of the clock load 1, and if the capacitor 3 is charged above the minimum operating voltage, it will naturally back up, but if it is completely discharged below the minimum operating voltage, the clock load will be Discharging to 1 is prohibited. In other words, the loss in the non-operating voltage range of the watch is mainly due to the self-discharge of the capacitor.

As seen in the above example, the watch is equipped with a detection circuit for the electromotive voltage of the solar cell and a detection circuit for the terminal voltage of the high-capacity capacitor, and the discharge circuit 1 is opened and closed depending on the level of the detected voltage. This prevents wasteful current loss during operation and shortens the charging time, making it possible to provide the optimal product as a solar battery wristwatch. It is also of great significance to expand the scope of application from secondary batteries to highly reliable electric double layer capacitors as backup for solar cells.

[Brief explanation of the drawing]

(A), (B), and (T) in Figure 1 are discharge circuit diagrams of a conventional solar powered wristwatch. FIG. 2 is a discharge circuit diagram of the solar battery wristwatch according to the present invention. 1... Clock load 2... Secondary battery 3... Electric double layer capacitor 4... Diode 5... Switch element 6... ... Flip-flop 7 ... Monthly carry signal 8 ... Solar cell output signal 9 ... Solar cell electromotive force detection circuit 10 ... Capacitor terminal voltage detection Circuit 11...Output signal from the capacitor terminal voltage detection circuit 12...Output signal from the solar cell electromotive voltage detection circuit 13...AND gate or more Applicant Suwa Co., Ltd. Seikosha Agent Patent Attorney Mogami Mugo (tsu) 24 pieces 1 ``This 1 Δ′ l

Claims (1)

[Claims] 1. A solar cell, a clock load, a high capacity capacitor,
In this solar battery wristwatch having means for charging a high-capacity capacitor, the watch load and the high-capacity capacitor are connected via a switch element, and the means for detecting the electromotive voltage of the solar cell and the terminal voltage of the high-capacity capacitor are detected. A solar powered wristwatch, comprising means for opening and closing the switch element in response to the level of detected voltage at the two locations. λ The switch element is turned on only when the terminal voltage of the high-capacity capacitor is equal to or higher than the set voltage and the electromotive voltage of the solar cell is equal to or lower than the set voltage with respect to a set voltage. Solar battery watch. 3. The solar battery wristwatch according to claim 1, comprising an electric double layer capacitor as the high-capacity capacitor. 4. The solar battery wristwatch according to claim 1, which includes a secondary battery as a high-capacity capacitor.