JP6930143B2 - Drive device, electronic clock and drive method - Google Patents

Description

The present invention relates to a drive device, an electronic clock and a drive method.

An electronic clock that operates on a button battery with a small capacity has a large power restriction when operating various devices. Moving the hands of an electronic clock while operating a sensor or a GPS (Global Positioning System) receiving IC (Integrated Circuit), for example, imposes a heavy load on power consumption. For example, Patent Document 1 discloses a technique relating to an electronic clock capable of reducing power consumption during reception processing of a satellite signal.

Japanese Unexamined Patent Publication No. 2012-194125

The most important thing in an electronic clock is an accurate time display. Even if the battery conditions deteriorate due to the temperature environment or the like, the electronic clock must guarantee accurate time display. It is necessary to consider that the guideline for displaying the time can move the hand even under extremely severe conditions. However, since the hands can be moved even under such severe conditions, the pulse applied to the stepping motor that drives the pointer consumes a large amount of current, which may shorten the battery life.

Therefore, it is an object of the present invention to appropriately select a pulse suitable for the current conditions from a plurality of types of pulses applied to a stepping motor in an electronic timepiece.

In order to achieve the above object, the present invention
Load and
A drive circuit that drives the stepping motor to move the pointer by applying a predetermined operation pulse to the stepping motor, and
When the load is not operated, a first operation pulse is applied to the stepping motor as the predetermined operation pulse to the drive circuit, and when the load is operated, the drive circuit is subjected to the predetermined operation pulse. As a control unit that applies a second operation pulse, which consumes less current than the first operation pulse, to the stepping motor.
It is a drive device characterized by being provided with.

According to the present invention, it is possible to appropriately select a pulse that matches the current conditions from a plurality of types of pulses applied to the stepping motor.

It is a block diagram which shows the outline of the electronic clock in this embodiment. It is a figure which shows the appearance of the dial of an electronic clock. It is a figure which shows the drive circuit of a stepping motor. This is a pulse waveform that is normally applied to the stepping motor. This is a pulse waveform applied to the stepping motor during GPS operation. It is a figure which shows the operation guarantee voltage range and the current consumption. It is a flowchart which controls a stepping motor. It is a figure which shows the drive circuit of the stepping motor of a modification. This is a pulse waveform that is normally applied to the stepping motor. This is a pulse waveform applied to the stepping motor during GPS operation.

Hereinafter, a mode for carrying out the present invention will be described in detail with reference to each figure.
FIG. 1 is a configuration diagram showing an outline of the electronic clock 1 in the present embodiment.
In the electronic clock 1 of the present embodiment, the rotating unit 51, the indicator unit 52, the hour / minute hand 53, and the second hand 54 can be driven by independent stepping motors 4a to 4d, respectively. The electronic watch 1 is, for example, a wristwatch-type electronic watch provided with a band for being worn on an wrist. The electronic clock 1 includes stepping motors 4a to 4d for rotationally driving a rotating unit 51, an indicating unit 52, an hour / minute hand 53, and a second hand 54 via each wheel train mechanism (not shown), a drive circuit 3, and a microcomputer 2. And have. The electronic clock 1 further includes an operation reception unit 61, a power supply unit 62, an oscillator 63, a GPS unit 7, and an antenna 71. In the figure, the stepping motors 4a to 4d are simply abbreviated as "motor".
Hereinafter, when the stepping motors 4a to 4d are not particularly distinguished, they are simply referred to as stepping motors 4.

The drive circuit 3 is a bridge circuit that drives each stepping motor 4, and constitutes a motor drive device in combination with the microcomputer 2. The microcomputer 2 is a main large-scale integrated circuit (LSI). The microcomputer 2 includes a CPU (Central Processing Unit) 21, an oscillation circuit 22, a frequency dividing circuit 23, and a timekeeping circuit 24.

The stepping motors 4a to 4d are, for example, high torque motors including a plurality of coils. The stepping motors 4a to 4d move the rotating unit 51, the indicating unit 52, the hour / minute hand 53, and the second hand 54 via a train wheel mechanism (not shown), and cause these pointers to point in a predetermined direction.

The hour hand 53a, the minute hand 53b, and the second hand 54 are rotatably provided with respect to the central rotation axis of the dial 8 (see FIG. 2). The disc hands constituting the rotating portion 51 are visible through a fan-shaped window drilled in the 6 o'clock direction of the dial 8, and are rotatably provided around its own rotation axis. The indicator 52 is an indicator hand provided in the 9 o'clock direction of the dial 8, and is rotatably provided about its own rotation axis.

The drive circuit 3 outputs a pulse for driving the stepping motor 4 at an appropriate timing based on the control signal input from the microcomputer 2. The drive circuit 3 can output by adjusting the pulse width applied to the stepping motor 4 based on the control signal from the microcomputer 2. The drive circuit 3 can output a drive voltage signal to the stepping motor 4 in the forward rotation direction or the reverse rotation direction. As a result, the drive circuit 3 can drive the stepping motor 4 to move the pointer.

The CPU 21 performs various arithmetic processes and controls the overall operation of the electronic clock 1 in an integrated manner. The CPU 21 reads and executes a control program from a ROM (Read Only Memory) (not shown), and continuously causes each unit to perform an operation related to time display. The CPU 21 causes the requested operation to be performed in real time or at a set timing based on an input operation by the switch or crown which is the operation receiving unit 61. This operation means, for example, reception of GPS signals, reception of sensor signals, and the like.

When the operation is accepted by these switches and crowns, the CPU 21 drives the stepping motor 4 by the drive circuit 3 to move the rotating unit 51, the indicator unit 52, the hour hand 53a, the minute hand 53b, and the second hand 54. The CPU 21 is a control unit that sets a target position for the hour hand 53a, the minute hand 53b, the second hand 54, the indicator unit 52, and the rotating unit 51 to move, and controls the drive of the stepping motor 4 by the drive circuit 3.

The oscillation circuit 22 generates a unique frequency signal and outputs it to the frequency dividing circuit 23. As the oscillation circuit 22, for example, a circuit that oscillates in combination with an oscillator 63 such as quartz is used.
The frequency dividing circuit 23 divides the signal input from the oscillation circuit 22 into signals of various frequencies used by the CPU 21 and the timekeeping circuit 24, and outputs the signal.

The timekeeping circuit 24 is a counter circuit that counts the number of times of a predetermined frequency signal input from the frequency dividing circuit 23 and adds the number of times to the initial time to count the current time. The current time counted by the timekeeping circuit 24 is read out by the CPU 21 and used for time display. The counting of this time may be controlled by software.

The operation receiving unit 61 is, for example, a crown, and receives a user's operation and transmits the operation to the microcomputer 2.
The power supply unit 62 has a configuration capable of continuously and stably operating the electronic clock 1 for a long period of time, and is, for example, a combination of a battery and a DC-DC converter. As a result, the output voltage of the power supply unit 62 during operation maintains a predetermined value.

The oscillator 63 is, for example, a crystal or the like, and is combined with the oscillation circuit 22 to generate a unique frequency signal.
The GPS unit 7 is composed of a GPS receiving IC, receives an ultra-high frequency satellite signal transmitted from a GPS satellite by an antenna 71, and measures a current position and a current time. The GPS unit 7 has a large load, and the lower limit of the operation guarantee voltage is higher than that of other parts.

The guaranteed operation voltage of each part constituting the electronic clock 1 is 1.0 V or more for the operation of the microcomputer 2, 1.65 V for the normal hand movement, and 1.86 V for the operation of the GPS receiving IC.
Considering the normal use of the electronic clock 1, it is necessary to cover the lower limit of the operation guarantee voltage of the hand movement up to 1.65V. However, when operating a high load such as a GPS receiving IC, it is not necessary to cover that much. Further, by relaxing the hand movement condition in this way, it is possible to move the needle with a pulse that suppresses the current consumption, or to move the hand faster with a short pulse.
Therefore, when the microcomputer 2 is operating a high load, another pulse with 1.8 V as the lower limit of the guaranteed operation voltage is applied to the stepping motor 4. As a result, the current consumption can be suppressed as compared with the normal pulse, and the overall power consumption can be reduced. It is also possible to move the hands faster than usual.

FIG. 2 is a diagram showing the appearance of the dial 8 of the electronic clock 1.
The electronic clock 1 includes a disk-shaped dial 8. The rotating portion 51 is rotatably provided with a disc needle about its own rotation axis, and is visible through a fan-shaped window drilled in the 6 o'clock direction of the dial 8. The indicator 52 is an indicator hand provided in the 9 o'clock direction of the dial 8 and can rotate about its own rotation axis.

At the center of the dial 8, the rotation axes of the hour hand 53a, the minute hand 53b, and the second hand 54 are provided. The disc needle of the rotating portion 51, "0 °", "60 °", etc. are engraved, and the engraving indicates the current longitude.
The indicator 52 is engraved with "0 °" in the left direction, "N" in the upward direction, and "S" in the downward direction. "30 °" and "60 °" are engraved between the "0 °" marking and the "N" marking. "30 °" and "60 °" are engraved between the "0 °" marking and the "S" marking. The indicator 52 indicates the current latitude by these markings and pointers.
If the current latitude and longitude are determined as a result of positioning by the GPS unit 7, the rotating unit 51 points to the longitude and the indicating unit 52 points to the latitude.

Hereinafter, the present embodiment will be described with reference to FIGS. 3 to 7. The stepping motor 4a of the present embodiment includes a plurality of coils, and step drive can be performed by applying a pulse to the plurality of coils.

FIG. 3 is a diagram showing a stepping motor 4a and a drive circuit 3 thereof.
In FIG. 3, a power supply voltage Vcc is applied by the power supply unit 62 between the voltage input end 31 and the ground end 32. Switch elements Q1 and Q2 are connected in series between the voltage input end 31 and the ground end 32 via the node N1. Similarly, the switch elements Q3 and Q4 are connected in series between the voltage input end 31 and the ground end 32 via the node N2, and the switch elements Q5 and Q6 are connected in series via the node N3. .. Further, the coil L1 of the stepping motor 4a is connected between the nodes N1 and N2, and the coil L2 is connected between the nodes N2 and N3. These coils L1 and L2 are coils that drive the stepping motor 4a. The switch elements Q1 to Q6 are, for example, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor).

The pulse P1 is a voltage pulse applied in the direction from the node N2 to the node N1 via the coil L1. The switch elements Q3 and Q2 are turned on, and the other switch elements Q1 and Q4 to Q6 are turned off. As a result, the power supply voltage Vcc is applied from the right end to the left end of the coil L1, and a current flows in the direction from the node N2 to the node N1. In this case, the pulse P1 becomes a positive pulse.

The pulse P2 is a voltage pulse applied in the direction from the node N3 to the node N2 via the coil L2. The switch elements Q3 and Q6 are turned on, and the other switch elements Q1, Q2, Q4 and Q5 are turned off. As a result, the power supply voltage Vcc is applied from the left end to the right end of the coil L2, and a current flows in the direction from the node N3 to the node N2. In this case, the pulse P2 becomes a negative pulse.

Further, the switch elements Q3, Q2 and Q6 are turned on, and the other switch elements Q1, Q4 and Q5 are turned off. In this case, the pulse P1 becomes a positive pulse and the pulse P2 becomes a negative pulse.

FIG. 4 is a waveform of the first operation pulse applied to the stepping motor 4 at normal times.
Here, the normal time means a case where a high load such as the GPS unit 7 or a sensor (not shown) is not operating.
In the period DP1, the drive circuit 3 applies a positive pulse P1 to the coil L1. In the next period DP2, the drive circuit 3 applies a negative pulse P2 to the coil L2. Further, in the period DP3, the drive circuit 3 applies a positive pulse P1 to the coil L1 and at the same time applies a negative pulse P2 to the coil L2.

The first operation pulse refers to a pulse applied to the coils L1 and L2 during the periods DP1 to DP3. The CPU 21 applies the first operation pulse to the stepping motor 4a by the drive circuit 3 to drive the stepping motor 4a for one step, thereby moving the disc needle.
As described above, the first operation pulse includes a period for driving the two coils at the same time.

FIG. 5 is a waveform of a second operation pulse applied to the stepping motor 4a during GPS operation.
Here, the time of GPS operation means the case where the GPS unit 7 having a high load is operating normally.
In the period DP1a, the drive circuit 3 applies a positive pulse P1 to the coil L1. In the next period DP2a, the drive circuit 3 applies a negative pulse P2 to the coil L2.
The second operation pulse refers to a pulse applied to the coils L1 and L2 during the periods DP1a and DP2a. The CPU 21 applies the second operation pulse to the stepping motor 4a by the drive circuit 3 to drive the stepping motor 4a for one step, thereby moving the disc needle.

As described above, the second operation pulse does not include the period for driving the two coils at the same time. Further, as shown in FIGS. 5 and 4, the second operation pulse is shorter than the first operation pulse. Therefore, the CPU 21 can also move the hands faster than in the normal operation by the second operation pulse.

FIG. 6 is a diagram showing an operation guaranteed voltage range and current consumption.
The operation guaranteed voltage range of the first operation pulse in the normal state shown in FIG. 4 is 1.65 to 2.10 [V], and the current consumption is 8.4 μA / STEP.
The pulse during GPS operation shown in FIG. 5 is the second operation pulse, the operation guaranteed voltage range is 1.80 to 2.10 [V], and the current consumption is 5.0 μA / STEP.
The lower limit of the guaranteed operation voltage of the GPS unit 7 (see FIG. 1) is 1.86 [V].

As described above, the lower limit of the operation guarantee voltage of the first operation pulse in the normal state is lower than the lower limit of the operation guarantee voltage of the high load (GPS reception IC). Further, the lower limit of the operation guarantee voltage of the second operation pulse during high load operation is set to the same level as the lower limit of the operation guarantee voltage of high load. The current consumption of the second operation pulse during high load operation is lower than the current consumption of the first operation pulse during normal operation. When the CPU 21 does not operate the high load, the drive circuit 3 applies the first operation pulse to the stepping motor 4a, and when the high load is operated (during the high load operation), the CPU 21 causes the drive circuit 3 to perform the second operation. A pulse can be applied to the stepping motor 4a. This makes it possible to reduce power consumption.

It is desirable that the lower limit of the operation guarantee voltage of the second operation pulse is set lower than the voltage at which the GPS unit 7 does not operate. As a result, even when the power supply voltage Vcc is lower than the lower limit of the operation guaranteed voltage of the GPS unit 7 and the GPS unit 7 is operating, the driving operation of the stepping motor 4 by the second operation pulse is guaranteed. Can be done.

FIG. 7 is a flowchart for controlling the stepping motor 4.
The CPU 21 executes this flowchart every time the stepping motor 4a is step-driven.
In step S10, the CPU 21 determines whether or not the GPS unit 7, which has a high load, is operating. If the GPS unit 7 is operating (step S10 → Yes), the CPU 21 outputs a second operation pulse (step S11). The second operation pulse has a lower limit of the operation guarantee voltage of 1.80 [V], which is higher than that of the first operation pulse described later, and the current consumption is smaller. As a result, the power consumption can be reduced and the decrease in the power supply voltage Vcc can be suppressed. As a result, the CPU 21 can preferably operate the GPS unit 7.
Further, since the GPS unit 7 is in operation, the current power supply voltage Vcc is higher than the lower limit of the guaranteed operation voltage of the GPS unit 7, and therefore higher than the lower limit of the guaranteed operation voltage of the second operation pulse. Therefore, the stepping motor 4a can be reliably driven and the hands can be reliably moved by the second operation pulse.

If the GPS unit 7 is not operating (step S10 → No), the CPU 21 outputs the first operation pulse (step S12). Here, the case where the GPS unit 7 is not operating includes the case where the CPU 21 is not operating the GPS unit 7 and the case where the GPS unit 7 is not operating even though the operation of the GPS unit 7 is attempted. The first operation pulse consumes a larger current than the second operation pulse, but has a lower lower limit of the guaranteed operation voltage of 1.65 [V]. As a result, the hands can be reliably moved even when the battery is exhausted.

Hereinafter, a modified example will be described with reference to FIGS. 8 to 10. The stepping motor 4a of the modified example includes a single coil. By applying a pulse to this single coil, step drive can be performed.
FIG. 8 is a diagram showing a drive circuit 3 of a modified stepping motor 4a.
In FIG. 8, a power supply voltage Vcc is applied by the power supply unit 62 between the voltage input end 31 and the ground end 32. Switch elements Q7 and Q8, which are MOSFETs, are connected in series between the voltage input end 31 and the ground end 32 via the node N4. Similarly, the switch elements Q9 and Q10 are connected in series between the voltage input end 31 and the ground end 32 via the node N5. Further, the coil L3 of the stepping motor 4a is connected between the nodes N4 and N5.

The pulse P3 is a voltage pulse applied in the direction from the node N5 to the node N4 via the coil L3. The switch elements Q9 and Q8 are turned on, and the other switch elements Q7 and Q10 are turned off. As a result, the power supply voltage Vcc is applied from the right end to the left end of the coil L3, and a current flows in the direction from the node N5 to the node N4. In this case, the pulse P3 becomes a positive pulse.

FIG. 9 is a waveform of the first operation pulse applied to the stepping motor 4a at normal times.
In the period DP4, the drive circuit 3 applies a positive pulse P3 to the coil L3. In the next period DP5, the drive circuit 3 applies a pulse with a duty of 50% to the coil L3. As described above, the normal pulse is a combination of the on period and the pulse period.
In the modified example, the normal pulse refers to a pulse applied to the coil L3 during the periods DP4 and DP5. The drive circuit 3 causes the stepping motor 4a to drive one step by the normal pulse, thereby moving the disc needle.

FIG. 10 is a waveform of a second operation pulse applied to the stepping motor 4a during GPS operation.
In the period DP4a, the drive circuit 3 applies a positive pulse P3 to the coil L3. The period DP4a is shorter than the normal period DP4. In the next period DP5a, the drive circuit 3 applies a pulse with a duty of 50% to the coil L3. As described above, the pulse during GPS operation is a combination of the on period and the pulse period.
The period DP5a is longer than the normal period DP5. And the sum of the period DP4 and the period DP5 is equivalent to the sum of the period DP4a and the period DP5a.

In the modified example, the first operation pulse in the normal state refers to a pulse applied to the coil L3 during the periods DP4a and DP5a. The drive circuit 3 causes the stepping motor 4a to drive one step by the first operation pulse, thereby moving the disc needle.
Also in the modified example, the electronic clock 1 has two or more operation pulses with different operation guarantee conditions for one hand. The first operation pulse is a normal pulse used in the above-mentioned normal clock timekeeping and the like. The second operation pulse is a pulse during high load operation that is used at the same time as high load.

However, the lower limit of the operation guarantee voltage of the first operation pulse during normal operation is smaller than the lower limit of the operation guarantee voltage of the high load (GPS receiving IC), and the lower limit of the operation guarantee voltage of the second operation pulse during high load operation is It is at the same level as the lower limit of the high load operation guarantee voltage. Further, the current consumption of the second operation pulse during high load operation is smaller than the current consumption of the first operation pulse during normal operation.
By setting in this way, it is possible to appropriately select a pulse that matches the current conditions, such as during high-load operation and normal operation. As a result, power consumption can be reduced.

(Modification example)
The present invention is not limited to the above-described embodiment, and can be modified without departing from the spirit of the present invention. For example, there are the following (a) to (g).

(A) The high load is not limited to the GPS receiving IC, but is a part that realizes other functions such as a sensor and a communication unit, and it can be determined from the microcomputer 2 whether or not these are operating normally. It should be.
(B) The second operation pulse during high-load operation may have a shorter on-period than the first operation pulse during normal operation.
(C) The second operation pulse during high load operation and the first operation pulse during normal operation are PWM signals, and the second operation pulse during high load operation has a higher on-duty than the first operation pulse during normal operation. It may be small.
(D) The voltage values of the second operation pulse during high load operation and the voltage value of the first operation pulse during normal operation are different, and the voltage of the second operation pulse during high load operation is higher than that of the first operation pulse during normal operation. It may be.
(E) The target for switching a plurality of pulses is not limited to the stepping motor that moves the rotating portion 51, and may be a stepping motor that moves any hand such as an hour hand, a minute hand, and a second hand.
(F) The electronic clock 1 may be moved faster than in the normal state by the second operation pulse in the high load operation. This makes it possible to add expressiveness to the movement of the pointer.
(G) The electronic clock 1 may have more pointers to move hands in parallel by the second operation pulse during high load operation than in the normal state. This makes it possible to add expressiveness to the movement of the pointer.

The inventions described in the claims originally attached to the application of this application are added below. The claims in the appendix are as specified in the claims originally attached to the application for this application.
[Additional Notes]

<< Claim 1 >>
Load and
A drive circuit that drives the stepping motor to move the pointer by applying a predetermined operation pulse to the stepping motor, and
When the load is not operated, a first operation pulse is applied to the stepping motor as the predetermined operation pulse to the drive circuit, and when the load is operated, the drive circuit is subjected to the predetermined operation pulse. As a control unit that applies a second operation pulse, which consumes less current than the first operation pulse, to the stepping motor.
A drive device characterized by being provided with.
<< Claim 2 >>
A load whose operation is guaranteed above the specified operation guaranteed voltage and
A drive circuit that drives the stepping motor to move the pointer by applying a predetermined operation pulse to the stepping motor, and
When the load is not operated, a first operation pulse is applied to the stepping motor as the predetermined operation pulse to the drive circuit, and when the load is operated, the drive circuit is subjected to the predetermined operation pulse. As a control unit, the stepping motor is applied with a second operation pulse having either the lower limit of the guaranteed operation voltage of the first operation pulse and the lower limit of the guaranteed operation voltage of the load as the lower limit of the guaranteed operation voltage. ,
A drive device characterized by being provided with.
<< Claim 3 >>
The second operation pulse has a shorter pulse width than the first operation pulse.
The driving device according to claim 1 or 2.
<< Claim 4 >>
The first operation pulse and the second operation pulse are a combination of an on period and a pulse period, and the on period of the first operation pulse is longer than the on period of the second operation pulse.
The driving device according to claim 1 or 2.
<< Claim 5 >>
The first operation pulse and the second operation pulse are PWM signals, and the second operation pulse has a smaller on-duty than the first operation pulse.
The driving device according to claim 1 or 2.
<< Claim 6 >>
The voltage of the second operation pulse is lower than that of the first operation pulse.
The driving device according to claim 1 or 2.
<< Claim 7 >>
The stepping motor includes two coils.
The first operation pulse includes a period for driving the two coils at the same time, and the second operation pulse does not include a period for driving the two coils at the same time.
The driving device according to claim 1 or 2.
<< Claim 8 >>
The drive device according to any one of claims 1 to 7.
An electronic clock characterized by that.
<< Claim 9 >>
The first operation pulse drive step of applying the first operation pulse to the stepping motor when the load is not operated, and
When operating the load, a second operation pulse drive step of applying a second operation pulse having a current consumption smaller than that of the first operation pulse to the stepping motor, and a second operation pulse drive step.
A driving method characterized by including.
<< Claim 10 >>
The first operation pulse drive step of applying the first operation pulse to the stepping motor when the load whose operation is guaranteed above the predetermined operation guarantee voltage is not operated, and
When operating the load, the stepping is performed by setting a second operation pulse having either the lower limit of the guaranteed operation voltage of the first operation pulse or the lower limit of the guaranteed operation voltage of the load as the lower limit of the guaranteed operation voltage. The second operation pulse drive step applied to the motor and
A driving method characterized by including.

1 Electronic clock 2 Microcomputer 21 CPU (control unit)
22 Oscillation circuit 23 Frequency division circuit 24 Time measurement circuit 3 Drive circuit 31 Voltage input end 32 Grounding end 4, 4a to 4d Stepping motor 51 Rotating unit 52 Indicator 53 Hour hand / minute hand 53a Hour hand 53b Minute hand 54 Second hand 61 Operation reception unit 62 Power supply unit 63 Oscillator 7 GPS unit (load)
71 Antenna 8 Dial Q1 to Q10 Switch element L1 to L3 Coil N1 to N5 Node P1 to P3 Pulse DP1 to DP3 Period (first drive pulse)
DP4, DP5 period (1st drive pulse)
DP1a, DP2a period (second drive pulse)
DP4a, DP5a period (second drive pulse)

Claims (10)

Load and
A drive circuit that drives the stepping motor to move the pointer by applying a predetermined operation pulse to the stepping motor, and
When the load is not operated, a first operation pulse is applied to the stepping motor as the predetermined operation pulse to the drive circuit, and when the load is operated, the drive circuit is subjected to the predetermined operation pulse. As a control unit that applies a second operation pulse, which consumes less current than the first operation pulse, to the stepping motor.
A drive device characterized by being provided with. A load whose operation is guaranteed above the specified operation guaranteed voltage and
A drive circuit that drives the stepping motor to move the pointer by applying a predetermined operation pulse to the stepping motor, and
When the load is not operated, a first operation pulse is applied to the stepping motor as the predetermined operation pulse to the drive circuit, and when the load is operated, the drive circuit is subjected to the predetermined operation pulse. As a control unit, the stepping motor is applied with a second operation pulse having either the lower limit of the guaranteed operation voltage of the first operation pulse and the lower limit of the guaranteed operation voltage of the load as the lower limit of the guaranteed operation voltage. ,
A drive device characterized by being provided with. The second operation pulse has a shorter pulse width than the first operation pulse.
The driving device according to claim 1 or 2. The first operation pulse and the second operation pulse are a combination of an on period and a pulse period, and the on period of the first operation pulse is longer than the on period of the second operation pulse.
The driving device according to claim 1 or 2. The first operation pulse and the second operation pulse are PWM signals, and the second operation pulse has a smaller on-duty than the first operation pulse.
The driving device according to claim 1 or 2. The voltage of the second operation pulse is higher than that of the first operation pulse.
The driving device according to claim 1 or 2. The stepping motor includes two coils.
The first operation pulse includes a period for driving the two coils at the same time, and the second operation pulse does not include a period for driving the two coils at the same time.
The driving device according to claim 1 or 2. The drive device according to any one of claims 1 to 7.
An electronic clock characterized by that. The first operation pulse drive step of applying the first operation pulse to the stepping motor when the load is not operated, and
When operating the load, a second operation pulse drive step of applying a second operation pulse having a current consumption smaller than that of the first operation pulse to the stepping motor, and a second operation pulse drive step.
A driving method characterized by including. The first operation pulse drive step of applying the first operation pulse to the stepping motor when the load whose operation is guaranteed above the predetermined operation guarantee voltage is not operated, and
When operating the load, the stepping is performed by setting a second operation pulse having either the lower limit of the guaranteed operation voltage of the first operation pulse or the lower limit of the guaranteed operation voltage of the load as the lower limit of the guaranteed operation voltage. The second operation pulse drive step applied to the motor and
A driving method characterized by including.

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