JPH0990062A - Electronic clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a stepping motor operate stably even at a low voltage. SOLUTION: This clock has a voltage level discriminating circuit 9 which discriminates the level of a supply voltage and a control circuit which is controlled by an output signal of the voltage level discriminating circuit 9 and passes selectively the respective output signals of a hand operating pulse generating circuit 3, a quick feed pulse generating circuit 5 and a reverse rotation pulse generating circuit 7. When the supply voltage becomes a prescribed voltage or below and a low voltage discrimination signal is generated from the voltage level discriminating circuit 9, the control circuit prohibits passing of a reverse rotation pulse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic timepiece having a step motor reverse rotation function.

[0002]

2. Description of the Related Art A conventional step motor for an electronic timepiece has a structure in which a rotor rotates only in a forward direction and does not rotate in a reverse direction in response to an input signal. Therefore, when it is desired to rotate the rotor in reverse for changing the pointer position, it is necessary to drive the rotor with a special reverse rotation pulse. Regarding this special reverse rotation pulse, Japanese Patent Laid-Open No. 52-80063 discloses an example of a reverse rotation pulse having two alternating pulses as one set and a reverse rotation pulse having three alternating pulses as one set. It is disclosed.

On the other hand, recently, solar cells (solar cells)
Which has a light source and converts light energy incident on the solar cell into electric energy and stores the electric energy in a capacitor or a secondary battery. The timepiece using the capacitor or the secondary battery as a power source, a so-called solar cell clock. Came to appear a lot.

This solar cell timepiece mainly stores electric energy in the daytime and discharges electric energy in the nighttime, and the voltage of the capacitor and the secondary battery changes considerably during the day. Therefore, especially in such a solar cell timepiece, it is desired that the step motor operates normally at a voltage as low as possible.

[0005]

However, the reverse rotation operation of the step motor described above has a narrower operating voltage width for normal operation than the normal rotation operation, and it is difficult to operate normally at a low voltage. Further, the forward rotation drive of the normal rotation also requires a narrow pulse width because the driving frequency is fast, so it is difficult to operate normally at a low voltage. An object of the present invention is an electronic timepiece which prohibits a reverse rotation operation of a step motor at a voltage lower than a predetermined voltage when operating an external operation member, and drives the step motor in a normal rotation with a wide pulse having a low driving frequency. To provide.

[0006]

A structure of the present invention for achieving the above object is to provide a hand movement pulse generating circuit for generating a hand movement pulse for normal hand movement and a forward rotation fast-forward pulse according to an operation of an external operation member. A fast-forward pulse generation circuit to be generated,
An electronic timepiece having a reverse rotation pulse generation circuit for generating a reverse rotation pulse according to an operation of an external operation member and a step motor for performing normal rotation, fast-forward forward rotation, and reverse rotation according to these pulses. And a voltage level discriminating circuit for discriminating the level of the power supply voltage and a control circuit controlled by the output signal of the voltage level discriminating circuit and selectively passing the output signal of each of the pulse generating circuits. When the voltage becomes equal to or lower than the voltage and a low voltage determination signal is generated from the voltage level determination circuit, the control circuit inhibits passage of the reverse rotation pulse.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. In the embodiment, the solar cell timepiece is operated every second, and the forward rotation fast-forward operation and the reverse rotation operation of the step motor will be described by taking the position correction of the time display hands as an example.

FIG. 1 is a circuit block diagram of an electronic timepiece according to the present invention. In FIG. 1, reference numeral 1 is an oscillator circuit, and 2 is a frequency divider circuit, which performs frequency division based on the output of the oscillation circuit 1 until a signal necessary for the operation of the timepiece is obtained.

Reference numeral 3 denotes a hand movement pulse generation circuit for generating a pulse for normal hand movement. During normal hand movement, a hand movement pulse having a pulse width of 5 ms as shown in FIG. 2A is output every one second. Four
Is a low-voltage hand movement pulse generation circuit, which outputs two hand movement pulses having a pulse width of 6 ms as shown in FIG. 2B every 2 seconds. Although it is a general technique at present, the rotation and non-rotation of the rotor 22 are detected after driving by the hand movement pulse, and a correction drive pulse having a wide pulse width is output from the hand movement pulse generation circuit 3 when the non-rotation is detected. Therefore, the low voltage hand movement pulse generation circuit 4 is not always necessary. 5
Is a fast-forwarding pulse generating circuit,
When is pressed continuously, a fast-forward pulse having a pulse width of 4 ms as shown in FIG. 2C is output every 64 seconds. The reason why the pulse width is made narrower than the pulse for normal hand movement is to increase the driving frequency. However, since the pulse width is narrow, it is difficult for the step motor to operate normally at a low voltage. Reference numeral 6 is a low-voltage fast-forward pulse generating circuit, which is continuously pressed as shown in FIG.
A fast-forward pulse with a pulse width of 6 ms as shown in 3
Output every two. The drive frequency is half and the pulse width is wider than the output of the fast-forward pulse generation circuit 5. Therefore, the step motor can operate normally even at a low voltage that cannot be driven by the output signal of the fast-forwarding pulse generation circuit 5.
Reference numeral 7 denotes a reverse rotation pulse generation circuit, which is an external operation member 3 described later.
When 5 is continuously pressed, a pulse is output every 32 seconds with one set of 3 pulses as shown in FIG. 2 (e).

A solar cell 8 converts light energy into electric energy and charges a capacitor as a power source or a secondary battery. A voltage level determination circuit 9 outputs a HIGH signal (hereinafter referred to as H signal) when the power supply voltage is a predetermined voltage, for example, 1.2 V or more, and outputs a LOW signal (hereinafter referred to as L signal) when the power supply voltage is less than 1.2 V. Output).
The voltage level discrimination circuit 9 is configured to forcibly flow a current when the power supply voltage is 1.8 V or higher, and prevent the power supply voltage from being 1.8 V or higher. Reference numeral 10 is a control circuit, and AND gates 11, 12, 13, 14, 15
And an OR gate 16. The output signal of the hand movement pulse generation circuit 3 is applied to the AND gate 11.
Further, the AND gate 12 outputs the output signal of the low voltage hand movement pulse generation circuit 4, the AND gate 13 outputs the output signal of the fast feed pulse generation circuit 5, and the AND gate 14 outputs the low voltage fast feed pulse. The output signal of the generation circuit 6 is the AND gate 1
The output signals of the reverse rotation pulse generation circuit 7 are applied to each of the signals 5. The AND gate 11, the AND gate 13, and the AND gate 15 are controlled by the direct output signal of the voltage level discriminating circuit 9, and the AND gate 12 and the AND gate are connected.
The gate 14 is controlled by the output signal from the inverter 23 of the voltage level discrimination circuit 9, and the AND gates 11, 12,
The output signals of 13, 14, and 15 are OR gates 16 respectively.
The output signal of the OR gate 16 is applied to the T terminal of the toggle flip-flop 17 and the AND gates 18 and 19.

Reference numeral 17 denotes a toggle flip-flop, which inverts the output signals of Q and Qbar when the output signal of the OR gate 16 rises, the Q output signal controls the AND gate 18, and the Qbar output signal is ANDed. It controls the gate 19. Reference numeral 20 denotes a drive circuit, which has two P
Channel MOS transistor and two N-channel M
It is composed of an OS transistor. A step motor coil 21 is connected to the output terminal of the drive circuit 19. 22 is a step motor rotor.
The rotation of the dial 22 is transmitted to the second hand 30, the minute hand 31, and the hour hand 32 shown in FIG. 3 via a time display train wheel (not shown).

S1, S2 and S3 are switches, which are connected to the power source VSS during normal hand movement.

In the above structure, first, the power supply voltage is 1.2.
The operation at the time of normal hand movement above V will be described.

Signals are output from the hand movement pulse generation circuit 3 and the low voltage hand movement pulse generation circuit 4 during normal hand movement, but since the power supply voltage is 1.2 V or higher, the AND gate 1 is used.
1 is on and the AND gate 12 is off. Therefore, the hand movement pulse which is the output signal from the hand movement pulse generation circuit 3 is passed through the OR gate 16 to toggle flip-flop 17, AND gate 18 and AND gate 19.
Is applied to If the Q output of the toggle flip-flop 17 becomes the H signal by the first hand movement pulse, AND gate
The gate 18 is turned on, and a hand movement pulse is applied to the drive circuit 20 via the AND gate 18. Therefore, a current flows through the coil 21, and the rotor 22 rotates in the positive direction by one step. At the next hand movement pulse, the Qbar output of the toggle flip-flop 17 becomes the H signal, so the AND gate 1
9 is turned on, and a hand movement pulse is applied to the drive circuit 20 via the AND gate 19. Therefore the coil 21
Current flows in the opposite direction to the front, and the rotor 22
Step Rotate in the forward direction. In this way, step mode
The stepper rotates in the forward direction step by step, and the second hand 30, minute hand 31, and hour hand 32 shown in FIG. 3 are driven by this rotation to display the time.

Next, the pointer position correcting operation when the power supply voltage is 1.2 V or more will be described. First, the case where the step motor is rotated forward to correct the pointer position will be described.

First, when the crown 33 which is the first external operating member shown in FIG. 3 is pulled out to the first stage, the switch S1 shown in FIG. 1 is connected to the VDD of the power source, and the frequency dividing circuit 2 is connected.
The subsequent stage is reset and the output signals of the hand movement pulse generation circuit 3 and the low voltage hand movement pulse generation circuit 4 are not generated. Next, when the push button 34 which is the second external operating member shown in FIG. 3 is pushed in, the switch S2 is connected to VDD, and the H signal is fed through the fast-forwarding pulse generation circuit 5 and the OR gate 24 to fast-forward for low voltage. It is applied to the pulse generation circuit 6. When the button is kept pressed for 1 second or more, output signals are continuously generated from the fast-forward pulse generating circuit 5 and the low-voltage fast-forward pulse generating circuit 6, and are applied to the AND gate 13 and the AND gate 14, respectively. However, since the power supply voltage is 1.2 V or higher, the AND gate 13 is in the ON state,
The gate 14 is in the off state, and the output signal of the fast-forward pulse generating circuit 5 is applied to the drive circuit 20 via the OR gate 16, the AND gate 18 or the AND gate 19. Therefore, the rotor 22 is fast-forwarded by forward rotation to correct the pointer position. When the push button 34 is released from the pushed-in state, it is biased by a spring (not shown), the switch S2 is connected to VSS again, and the pointer position correcting operation is not performed. When the pushing operation of the push button 34 is released in less than 1 second, only one pulse is generated. Then, when the crown 33 is pushed in, the switch S1 is connected to VSS again, the reset of the frequency dividing circuit 2 is released, and the normal hand movement state is established. When the crown 33 is pulled out to the second stage and rotated, the positions of only the minute hand 31 and the hour hand 32 can be corrected through the back wheel train as in a general timepiece. Further, when the crown 33 is pulled out to the second stage, the push buttons 34 and 35 cannot be pushed in due to the action of levers (not shown).

Next, the case where the step motor rotates in the reverse direction to correct the pointer position will be described.

After pulling out the crown 33 which is the first external operating member shown in FIG. 3, and pushing the push button 35 which is the third external operating member shown in FIG. 3, the switch S3 is connected to VDD. Then, the H signal is applied to the low voltage fast-forward pulse generating circuit 6 through the reverse rotation pulse generating circuit 7 and the OR gate 24. Reverse pressing pulse generation circuit 7 and low voltage fast-forward pulse generation circuit 6 when pressed for more than 1 second
Output signals are successively generated from the above and are applied to the AND gate 14 and the AND gate 15, respectively. However, since the power supply voltage is 1.2 V or higher, the AND gate 14 is off and the AND gate 15 is on.
Only the output signal of the reverse rotation pulse generation circuit 7 is the OR gate 1.
6 and the AND gate 18 or the AND gate 19 to be applied to the drive circuit 20. Therefore, the rotor 22 is fast-forwarded by reverse rotation and the pointer position is corrected. When the push button 35 is released from the pushed-in state, it is biased by a spring (not shown), the switch S3 is connected to VSS again, and the pointer position correcting operation is not performed. If the pushing operation of the push button 35 is released within 1 second, only one set of reverse rotation pulse is generated. Then, when the crown 33 is pushed in, the switch S1 is connected to VSS again, the reset of the frequency dividing circuit 2 is released, and the normal hand movement state is established.

Next, the operation of the normal hand movement when the power supply voltage is less than 1.2 V will be described.

When the power supply voltage becomes less than 1.2 V, the voltage level discriminating circuit 9 generates an L signal, that is, a low voltage discriminating signal, and the AND gate 11 of the control circuit 10 is turned off.
Since the AND gate 12 is turned on, the hand movement pulse which is the output signal of the low voltage hand movement pulse generation circuit 4 is applied to the drive circuit 20 via the OR gate 16 and the like. Therefore, a reverse current flows through the coil 21 alternately, and the rotor 22 is irregularly fed every 2 seconds and rotates in the forward direction. By this rotation, the second hand 30 and the minute hand 3 shown in FIG.
1, the hour hand 32 is driven. The irregular movement of the hand every 2 seconds indicates to the user that the power supply voltage has decreased.

Next, the operation of correcting the pointer position when the power supply voltage is less than 1.2 V will be described. First, the push button 3
A case where the pointer position is corrected by pushing 4 will be described.

When the crown 33 shown in FIG. 3 is pulled out to the first stage, the output signals of the hand movement pulse generation circuit 3 and the low voltage hand movement circuit 4 are not generated as described above. Next in FIG.
When the push button 34 indicated by is continuously pressed, the output signals are continuously generated from the fast-forwarding pulse generating circuit 5 and the low-voltage fast-forwarding pulse generating circuit 6 as described above, and A and
It is applied to the ND gate 13 and the AND gate 14. However, since the power supply voltage is less than 1.2V, this time AN
With the D gate 13 in the off state and the AND gate 14 in the on state, the output signal of the low voltage fast-forward pulse generation circuit 6 is applied to the drive circuit 20 via the OR gate 16 and the like. . Therefore, the rotor 22 is fast forwarded in the normal rotation to correct the pointer position. The pulse width at this time is wider than the pulse width at 1.2 V or more, and the driving frequency is low, so the step motor operates normally up to about 0.8 V. When the push button 34 is released, the switch S
2 is again connected to VSS, and the pointer position correcting operation is not performed. Thereafter, when the crown 33 is pushed in, the switch S1 is connected to VSS again, the reset of the frequency dividing circuit 2 is released, and the irregular hand movement state is set every 2 seconds.

Next, the case where the push button 35 is pushed to correct the pointer position when the power supply voltage is less than 1.2 V will be described.

When the push button 35 is continuously pressed after pulling out the crown 33 shown in FIG. 3, the output signals from the low voltage fast-forward pulse generating circuit 6 and the reverse rotation pulse generating circuit 7 are continuously output as described above. Occurrence and AND gate
Applied to the gate 14 and the AND gate 15. However, since the power supply voltage is less than 1.2 V, the AND gate 14 is on and the AND gate 15 is off.
Only the output signal of the low voltage fast-forward pulse generator 6 is ORed
It is applied to the drive circuit 20 via the gate 16 and the like. Therefore, the rotor 22 is fast forwarded in the normal rotation to correct the pointer position. That is, even if the push button 35 is pushed in, 1.2
The reverse rotation operation is not performed at a voltage lower than V. When the push button 35 is released from the pressed state, the switch S3 is connected to VSS again, and the pointer position correcting operation is not performed. Then push in the crown 33 to switch S1.
Is again connected to VSS, the reset of the frequency dividing circuit 2 is released, and the irregular hand movement state occurs every 2 seconds.

Although the forward rotation fast-forward operation and the reverse rotation operation of the step motor in the above embodiment have been described by taking the case of correcting the position of the time display hands as an example, the gist of the present invention is not limited to this. Various modifications can be made without departing from the scope of the present invention. For example, application to correction of the position of the alarm time display hands, return of the stopwatch hands to the initial position in an electronic timepiece having a stopwatch function, etc. is included in the scope of the present invention.

[0026]

As is apparent from the above description, according to the present invention, the reverse rotation operation of the step motor, which is difficult to normally operate at a low voltage, is prohibited when the power supply voltage becomes a predetermined voltage or less,
Further, since the drive pulse width for forward rotation is widened and the drive speed is slowed down, the step motor operates stably even at a low voltage, and its effect is great.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an electronic timepiece showing one embodiment of the present invention.

FIG. 2 is an output waveform diagram of a main part of the circuit block diagram shown in FIG.

FIG. 3 is an external view of an electronic timepiece showing an embodiment of the present invention.

[Explanation of symbols]

 3 Hand movement pulse generation circuit 5 Rapid feed pulse generation circuit 6 Low voltage rapid feed pulse generation circuit 7 Reverse rotation pulse generation circuit 9 Voltage level determination circuit 10 Control circuit

Claims (2)

[Claims] 1. A hand movement pulse generation circuit that generates a hand movement pulse for normal hand movement, a fast-forward pulse generation circuit that generates a forward rotation fast-forward pulse according to an operation of an external operation member, and a reverse movement pulse according to an operation of an external operation member. Reverse rotation pulse generation circuit that generates rotation pulses and normal rotation according to these pulses,
In an electronic timepiece having a step motor for performing forward-forward forward rotation and reverse-rotation operations, a voltage level determination circuit for determining the level of a power supply voltage and each pulse controlled by an output signal of the voltage level determination circuit A control circuit for selectively passing the output signal of the generation circuit is provided, and when the power supply voltage is out of a predetermined voltage range and a voltage discrimination signal is generated from the voltage level discrimination circuit, the control circuit prohibits passage of the reverse rotation pulse. An electronic watch characterized in that. 2. A low-voltage fast-forward pulse generating circuit for generating a pulse wider than the fast-forward pulse is provided, and when the power supply voltage becomes equal to or lower than a predetermined voltage and the low-voltage determining signal is generated from the voltage level determining circuit, The electronic timepiece according to claim 1, wherein the control circuit allows the low-voltage fast-forward pulse to pass when the external operation member is operated.