JP2021148430A - Stepping motor control device, movement, timepiece and stepping motor control method - Google Patents

Abstract

To provide a timepiece capable of obtaining a value of a power supply voltage dropped by driving of a stepping motor.SOLUTION: A stepping motor control device includes: a measurement part 124 for measuring a power supply voltage of a power supply which supplies electric power to a stepping motor 105 at the measuring timing corresponding to a driving method of the stepping motor 105; and a control part 103 for limiting the use of at least some of functions which consume electric power from the power supply and a hand movement system when the power supply voltage measured by the measurement part 124 is equal to or less than a predetermined threshold.SELECTED DRAWING: Figure 1

Description

The present invention relates to a stepping motor control device, a movement, a clock, and a stepping motor control method.

Conventionally, in a multifunctional clock equipped with a stepping motor, there has been a technique of measuring a power supply voltage during execution of a predetermined function and stopping the function that has been executed until then when the value falls below a predetermined threshold value. .. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-103178

However, the power supply voltage during function execution is not constant, and rises and falls repeatedly according to the drive pulse required to execute the function. On the other hand, the measurement timing of the power supply voltage is not taken into consideration, and the measurement is performed at a fixed timing. Therefore, even if the power supply voltage during function execution temporarily falls below a predetermined threshold value, a voltage exceeding the predetermined threshold value may be detected depending on the measurement timing of the power supply voltage. In this case, since the power supply voltage required for the stepping motor to operate normally cannot be secured, a problem such as a malfunction of the stepping motor occurs. Further, for example, when the clock has a built-in BLE microcomputer and a voltage is supplied to the BLE microcomputer from a power source common to the stepping motor, the BLE microcomputer does not operate normally.

The present invention has been made in view of such a situation, and a stepping motor control device, a movement, a clock, and a stepping motor capable of obtaining a value of a power supply voltage dropped by driving a stepping motor at a desired timing. The purpose is to provide a control method.

The stepping motor control device according to one aspect of the present invention has a measuring unit that measures the power supply voltage of a power source that supplies electric power to the stepping motor at a measurement timing according to a driving method of the stepping motor, and the measuring unit measures the voltage. When the power supply voltage is equal to or lower than a predetermined threshold value, it includes a control unit that limits the use of at least a part of the functions that consume the power of the power supply or the hand movement method.

In the stepping motor control device according to one aspect of the present invention, the measurement timing is a predetermined time during output of a drive pulse for rotating the rotor included in the stepping motor.

In the stepping motor control device according to one aspect of the present invention, the drive method of the stepping motor is forward rotation drive or reverse rotation drive.

In the stepping motor control device according to one aspect of the present invention, the measurement timing differs between the case where the stepping motor is driven in the forward direction and the case where the stepping motor is driven in the reverse direction.

The stepping motor control device according to one aspect of the present invention includes a specific unit that specifies a drive method of the stepping motor, a storage unit that stores the drive method of the stepping motor, and the measurement timing in association with each other. The measurement unit further includes an acquisition unit that acquires the measurement timing according to the drive method of the stepping motor specified by the specific unit from the storage unit, and the measurement unit is the power supply at the measurement timing acquired by the acquisition unit. Measure the voltage.

The movement according to one aspect of the present invention includes the above-mentioned stepping motor control device and the stepping motor.

The watch according to one aspect of the present invention includes the movement described above.

In the stepping motor control method according to one aspect of the present invention, the power supply voltage of the power supply that supplies electric power to the stepping motor is measured at the measurement timing according to the drive method of the stepping motor, and the measured power supply voltage is a predetermined threshold value. In the following cases, the use of at least a part of the functions that consume the power of the power source or the hand movement method is restricted.

According to the present invention, the value of the power supply voltage dropped by driving the stepping motor can be obtained at a desired timing.

It is a block diagram which shows an example of the functional structure of the analog electronic clock which concerns on embodiment. It is a figure which shows an example of correspondence information which concerns on embodiment. It is the schematic of the stepping motor and the motor drive part which concerns on embodiment. It is a power supply voltage waveform at the time of driving a stepping motor which concerns on embodiment. It is a figure for demonstrating a series of operations of the analog electronic clock which concerns on embodiment. It is a figure for demonstrating an example of the measurement timing at the time of the stepping motor forward rotation drive which concerns on embodiment. It is a figure for demonstrating an example of the measurement timing at the time of reverse driving of a stepping motor which concerns on embodiment. It is a figure for demonstrating an example of the measurement timing in the case where the stepping motor which concerns on embodiment is a two-coil motor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an example of the functional configuration of the analog electronic clock 1 according to the embodiment.

[Configuration of analog electronic clock 1]
As shown in FIG. 1, the analog electronic clock 1 stores the oscillation unit 101, the frequency dividing unit 102, the control unit 103, the motor drive unit 104, the stepping motor 105, the battery 120, the specific unit 121, and the storage unit. A unit 122, a measurement timing acquisition unit (acquisition unit) 123, a measurement unit 124, a train wheel (not shown), and an analog display unit 106 are provided.

The oscillating unit 101 generates a signal having a predetermined frequency.
The frequency dividing unit 102 divides the signal generated by the oscillating unit 101 to generate a clock signal that serves as a reference for timekeeping.
The control unit 103 controls each electronic circuit element constituting the analog electronic clock 1 and controls a pulse signal for driving the rotation of the motor.

The motor drive unit 104 drives the stepping motor 105 based on the pulse signal output by the control unit 103.
The stepping motor 105 is rotationally driven by a drive signal for driving the rotation of the motor output from the motor drive unit 104.

The battery 120 is, for example, a lithium battery, a so-called button battery. The battery 120 supplies electric power to various parts such as the stepping motor 105 included in the analog electronic clock 1. Hereinafter, the battery 120 is also referred to as a power source.
The battery 120 may be a storage battery that stores the electric power generated by the solar cell.

The identification unit 121 specifies the drive system of the stepping motor 105.
Here, the motor drive unit 104 controls the stepping motor 105 by a control method of either forward rotation drive or reverse rotation drive by the pulse signal output from the control unit 103. The identification unit 121 specifies the drive system of the stepping motor 105 by acquiring the drive system of the stepping motor 105 (for example, whether it is a forward rotation drive or a reverse rotation drive) from the control unit 103.
The specifying unit 121 may specify the driving method of the stepping motor 105 by another method based on a signal or the like output from the stepping motor 105. For example, the specifying unit 121 may specify the driving method of the stepping motor 105 based on the voltage across the coil included in the stepping motor 105. Further, the specifying unit 121 may specify the driving method of the stepping motor 105 based on the control signal output by the control unit 103.

The storage unit 122 stores the drive method of the stepping motor 105 and the measurement timing in association with each other as correspondence information. The measurement timing is a timing for measuring the voltage of the battery 120.
FIG. 2 is a diagram showing an example of correspondence information stored in the storage unit 122. Correspondence information will be described with reference to the figure. As shown in the figure, the drive system and the measurement timing are stored in the storage unit 122 in association with each other as correspondence information.
In the example shown in the figure, "D1", "D2" and "D3" are stored as the drive system. Further, "T1" is used as the measurement timing corresponding to the drive method "D1", "T2" is used as the measurement timing corresponding to the drive method "D2", and "T3" is used as the measurement timing corresponding to the drive method "D3". It is remembered.

In this example, the voltage of the battery 120 is measured when the measurement timing elapses after the drive pulse is applied to the stepping motor 105. That is, the measurement timing is a predetermined time after the drive pulse for rotating the rotor 202 included in the stepping motor 105 is output. Further, the measurement timing is information at the time when the current consumption becomes maximum (that is, the time when the voltage drop becomes maximum), which is determined for each drive method. Therefore, since the measurement timings are different for each drive method, the storage unit 122 stores different measurement timings for each drive method of the stepping motor 105.
The corresponding information stored in the storage unit 122 may be configured to change according to the value of an environmental sensor (temperature sensor or the like) (not shown) included in the analog electronic clock 1.
The corresponding information stored in the storage unit 122 may be updated by the -control unit 103 according to the product life of the analog electronic clock 1. For example, the control unit 103 may be configured to update the storage unit 122 according to the remaining capacity of the battery 120, the usage time of the battery 120, and the like.

Returning to FIG. 1, the measurement timing acquisition unit 123 acquires the measurement timing according to the drive method of the stepping motor 105 specified by the specific unit 121 from the storage unit 122.
A specific example will be described with reference to the example of FIG. When the measurement timing acquisition unit 123 acquires the drive system “D1” from the control unit 103, the measurement timing acquisition unit 123 acquires the measurement timing “T1” corresponding to the drive system “D1” from the storage unit 122.

Returning to FIG. 1, the measurement unit 124 acquires the measurement timing from the measurement timing acquisition unit 123. The measuring unit 124 measures the battery 120 voltage at the measurement timing while the motor driving unit 104 is driving the stepping motor 105. That is, the measurement unit 124 measures the voltage of the battery 120 at the measurement timing acquired by the measurement timing acquisition unit 123.
For example, the measuring unit 124 acquires information indicating the start of driving the stepping motor 105 from the motor driving unit 104, and measures the voltage of the battery 120 after a predetermined period indicated by the measurement timing has elapsed. The measuring unit 124 measures the voltage of the battery 120 by an A / D converter or the like (not shown).

The oscillating unit 101, the frequency dividing unit 102, the control unit 103, the motor drive unit 104, the specific unit 121, the storage unit 122, the measurement timing acquisition unit 123, and the measurement unit 124 are the stepping motor control unit (stepping motor control) of the analog electronic clock 1. Device) 112.

The train wheel (not shown) is rotationally driven by a stepping motor 105.
The analog display unit 106 is used for displaying the hour hand 107, the minute hand 108, and the second hand 109 (hereinafter, referred to as a pointer when the hour hand 107, the minute hand 108, and the second hand 109 are not distinguished) and the date display, which are rotationally driven by the train wheel. It has a calendar display unit 110 and the like.

Further, the analog electronic clock 1 includes a clock case 113. An analog display unit 106 is provided on the outer surface side of the watch case 113. The analog display unit 106 is a dial on which a scale is engraved.
Further, inside the watch case 113, a watch movement 114 including the above-mentioned train wheel is arranged. The movement 114 is a mechanical mechanism for driving each part of the analog electronic timepiece 1. The watch movement 114 includes a stepping motor control unit 112, a stepping motor 105, and a battery 120.

[Structure of motor drive unit 104 and stepping motor 105]
FIG. 3 is a diagram showing an example of the motor drive unit 104 and the stepping motor 105 according to the embodiment. The configuration of the motor drive unit 104 and the stepping motor 105 will be described with reference to the figure. The motor drive unit 104 includes a transistor TP1, a transistor TP2, a transistor TN1, a transistor TN2, a terminal ОUT1, and a terminal ОUT2.

The transistor TP1 and the transistor TP2 are P-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), which are turned on when a low-level gate signal is received and turned off when a high-level gate signal is received. Further, the transistor TN1 and the transistor TN2 are N-channel MOSFETs, and are turned off when a low-level gate signal is received and turned on when a high-level gate signal is received. The high-level potential is a potential equal to VDD, which is the power supply voltage of the motor drive unit 104. The low-level potential is 0 V or a potential equal to VSS, which is a reference voltage.

The sources of the transistor TP1 and the transistor TP2 are electrically connected to each other, and VDD, which is the power supply voltage of the motor drive unit 104, is supplied. Further, the drain of the transistor TP1 and the drain of the transistor TN1 are electrically connected to the terminal ОUT1. Further, the drain of the transistor TP2 and the drain of the transistor TN2 are electrically connected to the terminal ОUT2. The sources of the transistor TN1 and the transistor TN2 are electrically connected to each other, and VSS which is 0V or a reference voltage is supplied.

[Structure of stepping motor 105]
The stepping motor 105 includes a stator 201, a rotor 202, a rotor accommodating through hole 203, an inner notch 204, an inner notch 205, an outer notch 206, an outer notch 207, a magnetic core 208, and a coil 209. ..

The magnetic core 208 is a rod-shaped member made of a magnetic material, and is joined to both ends of the stator 201.

The coil 209 is wound around the magnetic core 208. One end of the coil 209 is connected to the terminal ОUT1, and the other end of the coil 209 is connected to the terminal ОUT2. The coil 209 generates a magnetic flux by passing a drive current Idrv.

The stator 201 is, for example, a member that is curved in a U shape and is made of a magnetic material. The stator 201 gives the rotor 202 the magnetic flux generated by the coil 209.

The rotor 202 is formed in a columnar shape, and is inserted into the rotor accommodating through hole 203 formed in the stator 201 in a rotatable state. Further, since the rotor 202 is magnetized, it has an N pole and an S pole. In the following description, the axis from the S pole to the N pole of the rotor 202 is also referred to as the magnetic pole axis A, and the direction from the S pole to the N pole of the magnetic pole axis A is the positive direction of the magnetic pole axis A (or simply the magnetic pole axis A). Also called direction).
The rotor 202 rotates the pointer 155 clockwise through the train wheel by rotating in the forward rotation direction, and rotates the pointer 155 counterclockwise through the train wheel by rotating in the reverse direction. That is, the rotor 202 can rotate in the forward rotation direction in which the pointer 155 is rotated clockwise and in the reverse rotation direction in which the pointer 155 is in the direction opposite to the forward rotation direction.

The inner notch 204 and the inner notch 205 are notches formed in the wall surface of the rotor accommodating through hole 203, and determine the stop position of the rotor 202 with respect to the stator 201. That is, for example, as shown in FIG. 2, when the coil 209 is not excited, the rotor 202 stands still at a position where the magnetic pole axis is orthogonal to the line segment connecting the inner notch 204 and the inner notch 205.

The outer notch 206 and the outer notch 207 are notches formed inside and outside the curved stator 201, respectively, and form a supersaturated portion between the outer notch 206 and the rotor accommodating through hole 203. Here, the supersaturated portion is a portion that is not magnetically saturated by the magnetic flux of the rotor 202, but is magnetically saturated when the coil 209 is excited, and the magnetic resistance increases.

FIG. 4 is a voltage waveform of the battery 120 when the stepping motor 105 is driven according to the embodiment. The voltage drop of the battery 120 will be described with reference to the figure. The horizontal axis of FIG. 4 indicates time, and the vertical axis of FIG. 4 indicates the voltage of the battery 120.
The figure is a diagram showing an example of the voltage waveform of the battery 120 when the stepping motor 105 is fast-forwarded and forward-rotated.

In this example, the control unit 103 controls the rotation angle of the rotor 202 by a drive pulse that rotates the rotor 202 by a predetermined angle and a holding pulse for holding the position of the rotor 202. FIG. 4 shows the time change of the voltage of the battery 120 when switching from a predetermined state such as a sleep state to a drive state.
Before time t2, it is a state (non-driving state) in which a predetermined function is not executed, such as a sleep state. Before time t2, the voltage fluctuation is between voltage v0 and voltage v1 and is stable. The maximum value of the voltage of the battery 120 before the time t2 is the voltage v0 at the time t0. The minimum value of the voltage of the battery 120 before the time t2 is the voltage v1 at the time t1.

After time t2, the control unit 103 drives the stepping motor 105 by the drive pulse and the holding pulse. After the time t2, the voltage fluctuation is between the voltage v2 and the voltage v3, and fluctuates greatly. The maximum value of the voltage of the battery 120 after the time t2 is the voltage v2 at the time t5 or the like. The minimum value of the voltage of the battery 120 after the time t2 is the voltage v3 at the time t6 and the like.

An example of a case where the forward rotation is driven by the drive pulse and the holding pulse has been described with reference to FIG. 4, but the timing at which the voltage of the battery 120 becomes the minimum value differs depending on the drive method. Therefore, in the present embodiment, different measurement timings are stored for each drive method, and the voltage of the battery 120 is measured at different measurement timings for each drive method. Therefore, in the present embodiment, the voltage can be measured at the timing when the voltage of the battery 120 becomes the minimum value.

FIG. 5 is a diagram for explaining a series of operations of the analog electronic clock 1 according to the embodiment. A series of operations of the analog electronic clock 1 will be described with reference to the figure.
(Step S10) The identification unit 121 specifies the drive system of the stepping motor 105. For example, the specific unit 121 acquires the drive system of the stepping motor 105 from the control unit 103.
(Step S20) The measurement timing acquisition unit 123 acquires the measurement timing according to the drive method acquired by the specific unit 121 from the storage unit 122.

(Step S30) When the drive pulse is applied (step S30; YES), the measuring unit 124 advances the process to step S40. When the drive pulse is not applied (step S30; NO), the measurement unit 124 continues the process of step S30 and waits until the drive pulse is applied. For example, the measuring unit 124 acquires information indicating that the drive pulse has been applied from the motor drive unit 104, and determines whether or not the drive pulse has been applied. The measuring unit 124 may be configured to determine whether or not a drive pulse has been applied by measuring the voltage across the coil 209.
(Step S40) When the drive pulse is applied, the measuring unit 124 measures the voltage of the battery 120 at the measurement timing acquired by the measurement timing acquisition unit 123. The measurement unit 124 provides the measurement result to the control unit 103.

(Step S50) The control unit 103 acquires the voltage of the battery 120 measured from the measurement unit 124. When the acquired voltage is equal to or less than a predetermined voltage value (step S50; YES), the control unit 103 advances the process to step S60. When the acquired voltage is not equal to or less than a predetermined voltage value (step S50; NO), the control unit 103 ends the process.

Here, the predetermined voltage value may be, for example, a voltage determined from the minimum operating voltage of a specific function. Various functions (for example, a compass function, a stopwatch function, etc.) included in the analog electronic clock 1 have a minimum operating voltage for each function. The predetermined voltage is a voltage at which some of the various functions included in the analog electronic clock 1 cannot be used, but other functions can be used. Hereinafter, a predetermined voltage is also referred to as a predetermined threshold value.
The predetermined threshold value may be stored in a storage unit (not shown).

(Step S60) When the voltage of the battery 120 is equal to or less than a predetermined threshold value, the control unit 103 limits a specific function. Specific functions include, for example, a compass function that consumes the power of the battery 120, a stopwatch function, and the like. That is, the control unit 103 limits the use of at least a specific function among the functions that consume the battery when the voltage of the battery 120 measured by the measurement unit 124 is equal to or less than a predetermined threshold value.
Specific functions include wireless communication functions such as Bluetooth (registered trademark) (Bluetooth), Wi-Fi (registered trademark), IrDA (Infrared Data Association), TransferJet (registered trademark), ZigBee (registered trademark), and others. It may be a peripheral function of.
Further, the control unit 103 limits the hand movement method when the voltage of the battery 120 is equal to or less than a predetermined threshold value. Here, the limitation of the hand movement method means reducing the number of simultaneous drive of the pointer, slowing down the drive frequency, switching the drive direction of the pointer to the one with the lighter load, and the like.

FIG. 6 is a diagram for explaining an example of measurement timing when the stepping motor 105 according to the embodiment is driven in the forward rotation.
In the figure, the time change of the voltage across the coil 209 included in the stepping motor 105 and the time change of the absolute value of the current flowing through the coil 209 included in the stepping motor 105 are shown. The horizontal axis in FIG. 6 indicates time. The vertical axis of the upper figure of FIG. 6 shows the voltage across the coil 209, and the vertical axis of the lower figure of FIG. 6 shows the current flowing through the coil 209. The figure is an example in the case where the stepping motor 105 is driven in the forward rotation.
In this example, the control unit 103 controls the rotation angle of the rotor 202 by forward rotation drive by a drive pulse for rotating the rotor 202 by a predetermined angle and a holding pulse for holding the position of the rotor 202.

From time t0 to time t50, the control unit 103 outputs a drive pulse for forward rotation drive to the motor drive unit 104. When a drive pulse for forward rotation drive is output to the motor drive unit 104, a voltage v, which is a battery voltage, is applied to both ends of the coil 209, and a current flows through the coil 209. The maximum value of the current from time t0 to time t50 is the current is.

From time t50 to time t70, the control unit 103 outputs a holding pulse to the motor drive unit 104. Here, the holding pulse is a chopping pulse that is chopped and driven at a predetermined cycle. When the holding pulse is output to the motor drive unit 104, an on state in which a voltage v, which is a battery voltage, is applied to both ends of the coil 209, and an off state in which no voltage is applied to both ends of the coil 209 are repeated. The maximum value of the current from time t50 to time t70 is the current i52 at time t52.

Here, the larger the current flowing through the coil 209, the lower the voltage of the battery 120. Therefore, it is desirable to measure the voltage of the battery 120 at the timing when the current flowing through the coil is large.
In this example, the maximum value of the current when the drive pulse is applied is the current is at the time ts, and the maximum value of the current when the hold pulse is applied is the current i52 at the time t52. Therefore, it is desirable that the measurement timing is time ts or time t52. It is more desirable that the measurement timing is set to the time ts during which the drive pulse is being applied.

FIG. 7 is a diagram for explaining an example of measurement timing when the stepping motor 105 according to the embodiment is reversely driven.
In the figure, the time change of the voltage across the coil 209 included in the stepping motor 105 and the time change of the absolute value of the current flowing through the coil 209 included in the stepping motor 105 are shown. The horizontal axis in FIG. 7 indicates time. Further, the vertical axis of the upper figure of FIG. 7 shows the voltage across the coil 209, and the vertical axis of the lower figure of FIG. 7 shows the current flowing through the coil 209. The figure is an example in the case where the stepping motor 105 is reversely driven.
In this example, the control unit 103 controls the rotation angle of the rotor 202 by reverse drive by a drive pulse for rotating the rotor 202 by a predetermined angle and a holding pulse for holding the position of the rotor 202.

From time t0 to time t73, the control unit 103 outputs a drive pulse for reverse drive to the motor drive unit 104. The control unit 103 applies a voltage v, which is a battery voltage, to both ends of the coil 209 at time t0.
At time t71, the control unit 103 applies a voltage −v, which is a voltage in the direction opposite to the voltage applied from time t0 to time t71. Therefore, from time t71 to time t72, a current flows through the coil 209 in the direction opposite to the current flowing from time t0 to time t71.
At time t72, the control unit 103 again applies a voltage v, which is the same voltage as the voltage applied from time t0 to time t71. Therefore, from time t72 to time t73, a current flows through the coil 209 in the same direction as the current that flowed from time t0 to time t71. The maximum value of the current flowing from time t72 to time t73 is the current is at time ts. The magnitude of the current flowing from time t72 to time t73 is larger than the magnitude of the current flowing from time t0 to time t71.

From time t73 to time t97, the control unit 103 outputs a holding pulse to the motor drive unit 104. When the holding pulse is output to the motor drive unit 104, an on state in which a voltage v, which is a battery voltage, is applied to both ends of the coil 209, and an off state in which no voltage is applied to both ends of the coil 209 are repeated. The maximum value of the current from time t73 to time t97 is the current i75 at time t75.

In this example, the maximum value of the current when the drive pulse is applied is the current is at the time ts, and the maximum value of the current when the hold pulse is applied is the current i75 at the time t75. Therefore, it is desirable that the measurement timing is time ts or time t52. It is more desirable that the measurement timing is the time ts during which the drive pulse is being applied.
That is, the measurement timing differs between the case where the stepping motor 105 is driven in the forward rotation and the case where the stepping motor 105 is driven in the reverse rotation.

In the above-described embodiment, an example in which the stepping motor 105 has one coil has been described, but in the embodiment of the present invention, the stepping motor 105 is similarly composed of two coils. Can be applied.
FIG. 8 is a diagram for explaining an example of measurement timing when the stepping motor according to the embodiment is a two-coil motor.
In the figure, when the stepping motor includes two coils (first coil and second coil), the voltage changes over time at both ends of the first coil (out1 and out2) and both ends of the second coil (out3 and out4). The time change of the voltage of) and the time change of the absolute value of the current flowing through the coil are shown. The horizontal axis in FIG. 8 indicates time. Further, the vertical axis of the upper two figures of FIG. 8 shows the voltage across the coil, and the vertical axis of the lower figure of FIG. 8 shows the current flowing through the coil. The figure illustrates an example of driving a stepping motor by two-layer excitation.

From time t0 to time td1, the control unit 103 applies a drive pulse P1 which is a pulse for rotating the rotor by 45 °. From time t0 to time td1, a voltage v, which is a battery voltage, is applied to one end (out1) of the first coil. As a result, the rotor is in a state of being rotated by 45 ° (first state).
From time td1 to time td2, the control unit 103 applies a drive pulse P2, which is a pulse for rotating the rotor by 135 ° from the first state. From time td1 to time td2, a voltage v, which is the same voltage as the voltage applied from time t0 to time td1, is applied to one end (out3) of the second coil. As a result, the rotor is rotated by 180 ° (second state).
From time td2 to time td3, the control unit 103 does not apply a voltage to both ends of each coil.
From time t3 to time td4, the control unit 103 applies a drive pulse P1 which is a pulse for rotating the rotor by 45 ° from the second state. From time t3 to time td4, a voltage v, which is a battery voltage, is applied to the other end (out2) of the first coil. As a result, the rotor is rotated by 225 ° (third state).
From time td4 to time td5, the control unit 103 applies a drive pulse P2, which is a pulse for rotating the rotor by 135 ° from the third state. From time td4 to time td5, a voltage v, which is the same voltage as the voltage applied from time t3 to time td4, is applied to the other end (out4) of the second coil. As a result, the rotor is in a state of being rotated by 3600 ° (first state).

In this example, the maximum value of the current from time t0 to time td5 is the current is at time td2 and td5. Therefore, it is desirable that the measurement timing is set to the times td2 and td5 during which the drive pulse P2 is being applied.

[Summary of Embodiment]
According to the embodiment described above, the stepping motor control unit 112 includes a specific unit 121, a storage unit 122, a measurement timing acquisition unit 123, a measurement unit 124, and a control unit 103. The measurement timing acquisition unit 123 acquires the measurement timing according to the drive method of the stepping motor 105 specified by the specific unit 121 from the storage unit 122. The measuring unit 124 measures the voltage of the battery 120 at the acquired measurement timing. That is, the stepping motor control unit 112 measures the voltage of the battery 120 at the measurement timing stored according to the drive system.
Therefore, according to the embodiment described above, the voltage can be measured at the timing when the voltage of the battery 120 becomes the minimum value. Since the minimum value of the voltage of the battery 120 differs depending on the drive method, the voltage can be measured at the timing when the voltage becomes the minimum value regardless of which drive method is used for driving.

Further, according to the embodiment described above, the measurement timing is a predetermined time after the drive pulse for rotating the rotor 202 included in the stepping motor 105 is output. That is, the measuring unit 124 measures the voltage of the battery 120 every cycle in which the drive pulse is output.
Therefore, according to the embodiment described above, the measurement result can be reflected from the next cycle in which the voltage of the battery 120 is measured, so that the voltage drop is measured even when a sudden voltage drop occurs. can do.

Further, according to the embodiment described above, the measurement timing differs between the case where the stepping motor 105 is driven in the forward rotation and the case where the stepping motor 105 is driven in the reverse rotation. Further, the timing at which the minimum value of the voltage of the battery 120 is reached differs between the case where the stepping motor 105 is driven in the forward rotation and the case where the stepping motor 105 is driven in the reverse rotation.
Therefore, according to the embodiment described above, it is possible to measure the minimum values during the forward rotation drive and the reverse rotation drive.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to the above-described embodiments, and design changes and the like are included without departing from the gist of the present invention.

1 ... Analog electronic clock, 101 ... Oscillating unit, 102 ... Dividing unit, 103 ... Control unit, 104 ... Motor drive unit, 105 ... Stepping motor, 106 ... Analog display unit, 107 ... Hour hand, 108 ... Minute hand, 109 ... Second hand , 110 ... Calendar display unit, 112 ... Stepping motor control unit, 113 ... Watch case, 114 ... Watch movement, 120 ... Battery, 121 ... Specific unit, 122 ... Storage unit, 123 ... Measurement timing acquisition unit, 124 ... Measurement unit , 201 ... Stator, 202 ... Rotor, 203 ... Rotor storage through hole, 204 ... Inner notch, 205 ... Inner notch, 206 ... Outer notch, 207 ... Outer notch, 208 ... Magnetic core, 209 ... Coil

Claims (8)

A measuring unit that measures the power supply voltage of the power supply that supplies power to the stepping motor at the measurement timing according to the drive method of the stepping motor.
A stepping motor including a control unit that limits the use of at least a part of the functions that consume the power of the power supply or the hand movement method when the power supply voltage measured by the measuring unit is equal to or less than a predetermined threshold value. Control device. The stepping motor control device according to claim 1, wherein the measurement timing is a predetermined time during output of a drive pulse for rotating the rotor included in the stepping motor. The drive system of the stepping motor is forward rotation drive or reverse rotation drive.
The stepping motor control device according to claim 1 or 2. The stepping motor control device according to claim 3, wherein the measurement timing differs between the case where the stepping motor is driven in the forward direction and the case where the stepping motor is driven in the reverse direction. A specific unit that specifies the drive system of the stepping motor,
A storage unit that stores the drive method of the stepping motor and the measurement timing in association with each other.
An acquisition unit that acquires the measurement timing according to the drive method of the stepping motor specified by the specific unit from the storage unit, and an acquisition unit.
With more
The measuring unit measures the power supply voltage at the measurement timing acquired by the acquiring unit.
The stepping motor control device according to any one of claims 1 to 4. The stepping motor control device according to any one of claims 1 to 5.
A movement including the stepping motor. A timepiece having the movement according to claim 6. The power supply voltage of the power supply that supplies power to the stepping motor is measured at the measurement timing according to the drive method of the stepping motor.
A stepping motor control method that limits the use of at least some of the functions that consume the power of the power supply or the hand movement method when the measured power supply voltage is equal to or less than a predetermined threshold value.

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