JPS6161077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic timepiece that uses a battery as a power source and displays the capacity of the battery by the amount of movement of the hands.

Traditionally, electronic watches use silver batteries as batteries.
Taking advantage of the characteristic of the battery's discharge characteristics, in which the battery voltage remains constant until the battery capacity is about to run out, by detecting the voltage at the end of discharge, the movement of the second hand was changed to indicate the battery life.

However, with the battery life display method, although it is possible to warn that the battery has run out of capacity, it is not possible to detect the battery capacity itself. Furthermore, when an electronic timepiece using a secondary battery is charged, for example, by a solar battery, it is not possible to know the remaining capacity of the secondary battery or the amount of charge.

The present invention is designed to eliminate such drawbacks, and uses a battery whose battery voltage changes in proportion to the battery capacity, and detects the battery voltage to change the amount of movement of the needle. It is designed to display battery capacity.

Hereinafter, the present invention will be described with reference to the drawings regarding an embodiment in which a lithium secondary battery is used as the secondary battery and a solar cell is used as the charging element. FIG. 1 is a block diagram for explaining the configuration of the present invention, in which 1 is a solar cell, 2 is a charging control circuit, 3 is a lithium battery, 4 is a battery voltage detection circuit, 5 is a clock circuit, 6 is a drive circuit, 7 is a display mechanism, and 8 is a switch for switching between normal time display and battery capacity display. FIG. 2 is a diagram schematically showing the relationship between the battery terminal voltage and battery capacity ratio of the lithium secondary battery 3. As is clear from FIG. 2, the terminal voltage of the lithium secondary battery 3 gradually increases as the battery capacity increases. In this way, compared to silver batteries, etc., lithium secondary batteries have the characteristic that the relationship between battery terminal voltage and battery capacity is roughly one-to-one, so it is easy to determine the remaining capacity from the terminal voltage. Using this characteristic, the battery voltage detection circuit 4 detects the terminal voltage of the lithium secondary battery 3, and the output of the battery voltage detection circuit 4 controls the clock circuit 5 to display the display mechanism 7. The battery capacity is displayed by changing the amount of movement of the hand. Furthermore, when the solar cell 1 is irradiated with light and an electromotive force is generated, the lithium secondary battery 3 is charged through the charging control circuit 2 and the battery capacity increases, and the terminal voltage of the lithium secondary battery 3 is as shown in FIG. The increase in capacity can be detected by the display mechanism 7 through the battery voltage detection circuit 4 and the clock circuit 5. Furthermore, in FIG. 1, switch 8 has a switch terminal connected to V _DD .
Under the control of the clock circuit 5, the display mechanism 7 can switch from normal time display to battery capacity display.

Next, the detailed operation of an embodiment in which the relationship between the battery capacity of the secondary battery and the amount of movement of the needle is determined as follows will be explained with reference to FIGS. 3 to 8.

Capacity ratio of secondary battery Amount of needle movement 80-100% 5 steps 60-80% 4 steps 40-60% 3 steps 20-40% 2 steps 0-20% 1 step Figures 3 and 4 show the above implementation. In a circuit diagram showing an example,
21 is a backflow prevention diode, 22 is a transistor, 51 is a pulse generation circuit, 52 is a counter, 5
3 is an up/down counter, and 54 is a down counter. 5 to 8 show signal waveforms of various parts for explaining the operation of FIG. 4.

First, the battery voltage detection circuit 4 will be explained.
The reference voltage is set according to the relationship shown in equation (1).

E _0MAX /2 > E ₁ > E ₂ > E ₃ > E ₄ > E _{0 MIN} /2 ...(1) Here, E _0MAX is the value of the secondary battery 3 (hereinafter the lithium battery 3 is referred to as the secondary battery 3). maximum value of terminal voltage,
E _0MIN is the minimum value of the terminal voltage of the secondary battery 3, E ₁ ,
E ₂ , E ₃ , and E ₄ are reference voltages having predetermined values so as to satisfy the relationship in equation (1).

E _0MAX /2 and E _0MIN /2 are connected to the terminal voltage of the secondary battery 3 by resistors r ₁ and r ₂ having the same resistance value.
It is created by dividing E ₀ into two.

If the terminal voltage E ₀ of the secondary battery 3 is as shown in equation (2), then E ₁ >E ₀ /2>E ₂ (2) In the battery voltage detection circuit 4, the reference voltage E ₁ The output of the D latch connected to the output of the comparator _C1 to which C1 is input becomes "0" level. At this time, the outputs of the comparators corresponding to E ₂ , E ₃ , and E ₄ are at the "1" level. In this way, it depends on which voltage level the voltage E ₀ /2 corresponding to the terminal voltage E ₀ of the secondary battery 3 is compared to the reference voltages E ₁ , E ₂ , E ₃ , and E ₄ . The output signal of the battery voltage detection circuit 4 can take on five different states. The voltage detection operation is performed using the output signal of the clock circuit 5, and the information regarding the terminal voltage _E0 of the secondary battery 3 detected at this time is obtained from the comparator C to which the highest reference voltage _E1 is input. Only the output of ₁ is memorized by the D latch. The reason for this is that the transistor 22 is controlled by the output of the D latch, and when the voltage E ₀ of the secondary battery 3 satisfies the equation (3): E ₀ /2>E ₁ ...(3), the transistor 22 is turned on. west,
This is to prevent overcharging of the secondary battery 3. Therefore, the input signal from the clock circuit 5 to the voltage detection circuit 4 is one that samples the comparator _C1 and controls the transistor 22 in the normal display state.
One displays the battery capacity by sampling comparators C ₁ to _{C 4} during the battery capacity display state, and the other displays the battery capacity.
There are different types.

Next, the operation of the timekeeping circuit 5 will be explained. In the normal display state, the signal at the output point A of the pulse generation circuit 51 is directly transmitted to the drive circuit 6, and the hands normally display the time. To change the normal time display to the battery capacity display, switch 8 is turned on momentarily. When switch 8 is momentarily turned on, point M becomes “1” momentarily.
level, the counter 52 and up-down counter 53 are reset, and the down counter 54 is set to the value "11". At the same time, the output of NOR2 becomes "0" level, and A displays the normal time.
The point signal is no longer transmitted to the drive circuit 6, and the movement of the needle stops. When the output of NOR2 becomes "0" level, for example, the 1 second signal at point A is input to the counter 52, and the 5 pulses are counted.
GATE2 opens and point C becomes level “1”. C
At the "1" level of the point, the sampling signal B to the battery voltage detection circuit 4 becomes each signal as shown in FIG.
B ₁ to _{B 4} , and the output signal of battery voltage detection circuit 4
_D1 to _D4 are as shown in FIG. 6a, b, and c, for example. The signals D ₁ to _{D 4} shown in Figure 6 are as follows: when the battery capacity ratio is 80% to 100% in case a, and when the battery capacity ratio is 80% to 100% in case b.
When it is 60 to 80%, the case of c is when it is 0 to 20%. As shown in Figure 6a below, the battery capacity ratio is 80-100%
Taking the case as an example, the output signals _D1 to _D4 of the battery voltage detection circuit 4 enter NOR1;
The signal at the output point F is as shown in FIG. 6a. This signal enters the up-down counter 53 as shown in FIG.
For 3, the count increases by 5. A signal used to display the battery capacity is output to the output point G of AND2. After this signal is counted up by the up-down counter 53 five times, AND3 is opened at the "1" level of the signal at point E. , enters the up-down counter 53 and decreases the count by five.
When the up-down counter 53 counts down by 5, GATE 5 closes, so if it is 5 or more, it is H.
It doesn't reach the point. The H point signal is transmitted to the drive circuit 6 through OR2 and OR1, the needle moves 5 steps, and the battery capacity is displayed. Also, the signal at point H is
It is also input to the down counter 54 via the output point K of OR2, and the preset value "11" of the down counter 54 is decreased by 5, and GATE6 is opened. When further time passes and the counter 52 counts 10 signals output to point A, GATE 3 opens, a signal appears at the 1 output point of AND 6, and the down counter 54 counts the remaining count number "6". The signal is counted down by 6 until GATE 6 closes, and the signal until GATE 6 closes is transmitted to the drive circuit 6, and the needle moves. The reason for moving the hands after the battery capacity display is to correct the time display so that it correctly points to the current time when the battery capacity display state returns to the normal time display state. When the counter 52 counts the 11th pulse of the signal at point A after a certain period of time has elapsed,
The output of GATE4 momentarily becomes “1” level,
This signal is input to the NOR 3, and the output of the NOR 2 becomes "1" level, so that the signal at point A does not enter the counter 52, but is input to the drive circuit 6, and the hands start normal operation again.

Next, as shown in Figure 6b, the battery capacity ratio is 60~
The case of 80% will be described below, focusing on the differences from the case of the battery capacity ratio of 80 to 100% described above. The counter 52 is activated by the signal at point A from the momentary ON of switch 8.
When counts “5”, the output point C of GATE2 becomes “1” level and the sampling signal B becomes the fifth level.
The result will be as shown in the figure. Therefore, the output signals D ₁ to _{D 4} of the battery detection circuit 4 are as shown by b in FIG. 6. The signal at the output point F at b in FIG. 6 is input to the up-down counter 53, as shown in FIG. 7, and is counted up by four. After that, the signal at the output point G of AND2 counts down five times until GATE5 closes. Therefore, similarly, four pulses are output at the H point, and the four pulses at the output K point are transmitted via OR2 to the drive circuit 6 and the down counter 54, which is set to the value "11". Then, while moving the pointer by four positions to display the battery capacity ratio, the down counter 54 is counted down by four positions and the count is set to "7". Then, when the counter 52 counts the 10th signal at point A, GATE3 opens and the down counter 54 continues until GATE6 is closed by the signal at the output point of AND6.
By counting down by 7, correction is made when the display returns to the normal time display state after displaying a battery capacity ratio of 60 to 80%. Furthermore, as time passes, A
When the counter 52 counts the 11th point signal, GATE4 momentarily goes to the “1” level, and the NOR
The output of NOR2 is set to “0” level, and therefore, NOR2
By setting the output to "1" level, the signal at point A is transmitted to the drive circuit 6 through AND5, and the counter 5
In step 2, the signal at point A is inhibited, the display returns to the normal time display state, and the series of battery capacity display operations is completed. FIG. 8 shows how the needle moves depending on the battery capacity ratio. After the signal is input to point M, the signals at point A are input from 1st to 11th.
Let the numbers be a to k. In particular, e, j, and k are the 5th, 10th, and 11th signals at point A, respectively. L ₁ to _{L 5} are signals at the input L point of the drive circuit 6 depending on the battery capacity ratio,
L ₁ is 80-100%, L ₂ is 60-80%, L ₃ is 40-60%,
_L4 is a drive signal indicating a battery capacity ratio of 20 to 40%, and _L5 is a drive signal indicating a battery capacity ratio of 0 to 20%. Of the above signals, the operation when the battery capacity ratio is 80 to 100% and 60 to 80% is as described above, but the basic operation is the same in other cases, so we will omit it here. .

Above, we have described an example in which a lithium secondary battery is used as the secondary battery and a solar cell is used as the charging element, but there are also other batteries other than secondary batteries, such as lithium secondary batteries, where the output voltage and battery capacity correspond on a one-to-one basis. Needless to say, the same effect can be obtained even if a power source of 1 is used or an element other than a solar cell is used as the charging element. Further, it is also possible to provide a hand other than the one normally used to display the time to display the battery capacity. Further, although the present invention has been described as displaying battery capacity, it goes without saying that the same effect can be obtained even if battery capacity is replaced with battery voltage, and it is also possible to display battery voltage.

As described above, the configuration of the present invention has the following effects. As an electronic watch, (1) you can know how much time it can be used without charging, so you can use it with confidence.

(2) Since you can tell when it is time to charge, it is useful for stopping the clock function or preventing it from stopping. At the same time, since overcharging of the battery can be prevented, the useful life of the battery can be extended.

(3) Since the amount of charge can be determined, it is possible to charge the battery appropriately, prolonging the battery's useful life and avoiding unnecessary charging.

(4) If you use a battery such as a lithium secondary battery that has characteristics such as good leakage resistance, low self-discharge rate, and long service life, you can have the effects of (1) to (3) above. , it is possible to realize an electronic clock with a long battery life.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the configuration of the present invention, FIG. 2 is a diagram showing the relationship between battery terminal voltage and battery capacity ratio of a lithium battery, and FIG.
4 are circuit diagrams showing embodiments of the present invention, and FIGS. 5, 6, 7, and 8 are diagrams showing signal waveforms at various parts in FIG. 4. 1...Solar cell, 2...Charging control circuit, 3...
Secondary battery, 4... Battery voltage detection circuit, 5... Timing circuit, 6... Drive circuit, 7... Display mechanism, 8...
Switch, 21... Backflow prevention diode, 22...
...Transistor, 51...Pulse generation circuit, 52
... Counter, 53 ... Up-down counter,
54...down counter, TG...transmission gate, _r1 , _r2 ...resistance, _E0 ...terminal voltage of secondary battery 3, _E1 , _E2 , _E3 , _E4 ...reference voltage ,
C ₁ , C ₂ , C ₃ , C ₄ ... Comparator, INV1, INV
2...Inverter, GATE1, GATE2, GATE
3, GATE4, GATE5, GATE6... Gate circuit, AND1, AND2, AND3, AND4, AND
5, AND6, AND7, AND8...AND circuit,
OR1, OR2, OR3...OR circuit, NOR1,
NOR2, NOR3...NOR circuit.

Claims (1)

[Claims] 1. A power supply section consisting of a battery or a secondary battery, a pulse signal generating means that outputs a plurality of signals including a clock signal that normally measures and displays the time, a display mechanism that displays time information using a hand, and a display mechanism that normally outputs the clock signal. a drive circuit that inputs a voltage to drive the display mechanism, a voltage detection means that outputs a voltage display signal in which the number of pulses in the signal output increases or decreases depending on the output voltage value of the power supply section, and an operation of an external switch. The input of the clock signal to the drive circuit is prohibited for a certain period of time, and the voltage detection means is operated to input the voltage display signal to the drive circuit to detect the voltage according to the output voltage value of the power supply section. a control means for driving the pointer by the number of pulses of the display signal and performing a voltage display operation according to the amount of movement; and a changing storage means, the pulse signal corresponding to the changed storage content of the storage means is changed to the pulse signal according to a signal output from the control means that detects a predetermined time after the voltage display operation is performed. The signal generation means inputs a correction signal to the drive circuit to set the pointer to the current time, and the pulse signal is input to the storage means, and after outputting the correction signal, the control means transmits the clock signal to the drive circuit. , and the sum of the number of pulses of the voltage display signal and the number of pulses of the correction signal is the sum of the clock signal output from when the external switch is operated until the pointer returns to the current time. An electronic clock characterized by the same number of pulses.