JP2009148143A - Stepping motor control circuit and analog electronic timepiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save energy by reducing use of correction driving pulses as much as possible. <P>SOLUTION: A rotation detecting signal Vmax over a reference threshold voltage Vcomp is changed to a main driving pulse P1 with more energy when the rotation detecting signal is detected in a first time range T1 or a third time range T3, in rotating a stepping motor with the main driving pulse P1. The main driving pulse P1 is not changed when the signal is detected in a second time range T2 as a principle. When the motor can be continuously driven a predetermined number of times by the same main driving pulse P1, the main driving pulse P1 is changed to a main driving pulse P1 with low energy, if the main driving pulse P1 is not a main driving pulse P1 with minimum energy. When the rotation detecting signal Vmax over the reference threshold voltage Vcomp is not detected, the signal is changed to a main driving signal P1 with high energy, after forcible rotation by a correction driving pulse P2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stepping motor control circuit and an analog electronic timepiece having the stepping motor control circuit.

  2. Description of the Related Art Conventionally, a stator having a rotor housing hole and a positioning portion for determining a stop position of the rotor, a rotor disposed in the rotor housing hole, and a coil, and supplying an alternating signal to the coil to supply the stator A stepping motor that rotates the rotor by generating a magnetic flux and stops the rotor at a position corresponding to the positioning portion is used in an analog electronic timepiece or the like.

FIG. 4 is a configuration diagram of a stepping motor 105 conventionally used in an analog electronic timepiece or the like.
In FIG. 4, a stepping motor 105 includes a stator 201 having a rotor accommodating through hole 203, a rotor 202 rotatably disposed in the rotor accommodating through hole 203, a magnetic core 208 joined to the stator 201, and a winding around the magnetic core 208. A rotated coil 209 is provided.

When the stepping motor 105 is used in an analog electronic timepiece, the stator 201 and the magnetic core 208 are fixed to a base plate (not shown) with screws (not shown) and joined to each other. The coil 209 has a first terminal OUT1 and a second terminal OUT2.
The rotor 202 is magnetized to two poles (S pole and N pole). Two notches (outer notches) 206 and 207 are provided on the outer end portion of the stator 201 formed of a magnetic material at positions facing each other with the rotor accommodating through hole 203 interposed therebetween. Saturable portions 210 and 211 are provided between the outer notches 206 and 207 and the rotor accommodating through hole 203.

The saturable portions 210 and 211 are configured not to be magnetically saturated by the magnetic flux of the rotor 202 but to be magnetically saturated when the coil 209 is excited to increase the magnetic resistance. The rotor accommodating through hole 203 is formed in a circular hole shape in which two half-moon-shaped notches (inner notches) 204 and 205 are integrally formed at a portion opposite to a through hole having a circular outline.
The notches 204 and 205 constitute a positioning part for determining the stop position of the rotor 202. In a state where the coil 209 is not excited, the rotor 202 has a position corresponding to the positioning portion as shown in FIG. 4, in other words, a line segment connecting the notches 204 and 205 with the magnetic pole axis of the rotor 202. It is stopped stably at a position (θ0 direction) that is orthogonal.

  Now, a rectangular-wave drive pulse is supplied from the drive pulse selection circuit between the terminals OUT1 and OUT2 of the coil 209 (for example, the first terminal OUT1 side is positive and the second terminal OUT2 side is negative), and the direction of the arrow in FIG. When a current i is passed through the stator 201, a magnetic flux is generated in the stator 201 in the direction of the broken arrow. Thereby, the saturable portions 210 and 211 are saturated and the magnetic resistance is increased, and then the rotor 202 rotates 180 degrees counterclockwise due to the interaction between the magnetic pole generated in the stator 201 and the magnetic pole of the rotor 202, Stop stably.

Next, a drive pulse having a reverse polarity rectangular wave is supplied from the drive pulse selection circuit to the terminals OUT1 and OUT2 of the coil 209 (the first terminal OUT1 side has a negative polarity and a first polarity so that the polarity is opposite to that of the drive). When the current flows in the opposite arrow direction in FIG. 4, magnetic flux is generated in the stator 201 in the opposite arrow direction. As a result, the saturable portions 210 and 211 are first saturated, and then the rotor 202 rotates 180 degrees in the same direction as described above due to the interaction between the magnetic poles generated in the stator 201 and the magnetic poles of the rotor 202, and stably stops. To do.
Thereafter, by supplying signals with different polarities (alternating signals) to the coil 209 in this way, the above operation is repeated, and the rotor 202 can be continuously rotated 180 degrees in the direction of the arrow. It is configured as follows.

On the other hand, as a driving method of the stepping motor 105, when the stepping motor 105 is driven by the main drive pulse, the rotation detection circuit detects an induced voltage (rotation detection signal) generated in the stepping motor 105 and determines whether or not the stepping motor 105 has rotated. However, depending on whether or not it is rotated, the correction drive method is changed to the main drive pulse having a different pulse width, or is forcibly rotated by the correction drive pulse having a pulse width larger than each main drive pulse. It is used (for example, refer to Patent Document 1).
The rotation detection circuit provides a predetermined detection time after a predetermined mask time during which no rotation detection signal is detected, and a stepping motor is detected when a rotation detection signal exceeding a predetermined reference threshold voltage Vcomp is detected within the detection time. It is comprised so that it may determine with 105 rotating.

By the way, the detection timing of the rotation detection signal changes depending on the eccentricity of the rotor 202, the voltage drop of the power supply battery, the use of a second hand or minute hand having a large moment of inertia.
Referring to FIG. 4, the state in which the induced voltage is generated according to the behavior of the rotor 202 will be described. (I) When the rotor 202 rotates and passes through the saturable portion 210 (arrow a portion), X passing through the magnetic core 208 from the rotor 202 The magnetic flux in the direction of the arrow on the axis increases, and an induced voltage is generated in a direction (a direction opposite to the current i for generating the main drive pulse P1) that prevents this.

  (Ii) When the rotor 202 exceeds the inner notch 205 and passes the horizontal magnetic path (X-axis) direction (arrow b portion), the magnetic flux passing through the magnetic core 208 from the rotor 202 decreases, and this is obstructed (same as the current i). Direction). That is, an induced voltage is generated in the direction opposite to (i). (Iii) When the rotor 202 rotates past the next stable stationary angle θ1 advanced 180 degrees from the initial angle θo and then returns to θ1 (arrow c portion), the magnetic flux passing through the magnetic core 208 increases from the rotor 202, An induced voltage is generated in the same direction as (i).

The induced voltage of (i) is also output in the direction of the reference threshold voltage Vcomp as in (iii), so that the induced voltage of (i) is the reference threshold even though the rotor 202 is not rotating. If the voltage Vcomp is exceeded, it is erroneously determined that the rotation has occurred.
Therefore, as described above, after the main drive pulse P1 is output, a mask time IT in which the rotation detection signal is not detected is provided, and the value of the mask IT is set so that the rotation detection signal in (i) is masked. ) Of the rotation detection signal exceeds the reference threshold voltage Vcomp to prevent erroneous determination of rotation.

However, the generation time of the induced voltage changes according to the behavior of the rotor 202 due to the influence of the eccentricity of the rotor 202, in other words, the eccentricity of the rotor 202, the voltage drop of the power supply battery, the second hand and the minute hand having a large moment of inertia. The generation timing of the rotation detection signal indicating that the rotor 202 has rotated due to use or the like changes.
For example, when the rotation of the rotor 202 is slowed due to the eccentricity of the rotor or the like, an induced voltage that is normally generated within the mask time IT is generated by shifting within the detection time, and a rotation detection signal exceeding the reference threshold voltage Vcomp. Detected as

In the system in which the energy of the main drive pulse P1 is changed depending on whether the detection time point of the rotation detection signal exceeding the reference threshold voltage Vcomp is early or late, the rotation detection signal is detected at an early time point. Although the main drive pulse has no margin of energy, it is erroneously determined that the main drive pulse has been rotated with sufficient margin, and erroneously controlled to lower the rank of the main drive pulse.
In this case, it becomes impossible to rotate the stepping motor with the rank-decreased main drive pulse, and after driving with the correction drive pulse P2, the main drive pulse is ranked up. Therefore, driving by the correction driving pulse P2 is performed, and there is a problem that power consumption increases.

Japanese Patent Publication No. 61-15385

  The present invention has been made in view of the above problems, and it is an object of the present invention to reduce the drive by the correction drive pulse to achieve power saving by driving with an appropriate main drive pulse.

According to the present invention, when a rotation detection signal generated by the rotation of a stepping motor is detected in a detection time after a predetermined mask time has elapsed, and the rotation detection signal exceeds a predetermined reference threshold voltage within the detection time The rotation detection means for determining that the stepping motor has rotated at the same time, and a plurality of main drive pulses having different energy from each other, or energy higher than each of the main drive pulses, depending on the determination result by the rotation detection means. Control means for driving the stepping motor with a large correction drive pulse, and the detection time is set to a first interval, a second interval after the first interval, and a second interval after the second interval. The controller is divided into three sections, and the control means exceeds the predetermined reference threshold voltage when driven by any one of the main drive pulses. That when the rotation detection signal detected in the first period, the stepping motor control circuit, characterized in that the drive is changed to a large main drive pulse of energy than the main drive pulse is provided.
When the control means detects a rotation detection signal exceeding a predetermined reference threshold voltage in the first section when driven by any of the main drive pulses, the control means determines that the main drive pulse has a larger energy than the main drive pulse. Change and drive.

Here, when the control means is driven by any one of the main drive pulses, the control means also detects the rotation detection signal exceeding the predetermined reference threshold voltage in the third section. You may comprise so that it may change and drive to the main drive pulse with big energy.
Further, when the control means detects a rotation detection signal exceeding the predetermined reference threshold voltage in the first section or the third section when driven by any one of the main drive pulses, the main drive pulse is In the case of maximum energy, the main drive pulse may not be changed.

The control means does not change the main drive pulse when it is driven by any one of the main drive pulses and detects a rotation detection signal exceeding the predetermined reference threshold voltage in the second section. You may comprise as follows.
Further, when the rotation detecting signal exceeding the predetermined reference threshold voltage is continuously detected a predetermined number of times in the second section, the control means changes the main driving pulse to a main driving pulse having a small energy. You may comprise so that it may drive.
The controller may be configured not to change the main drive pulse when the main drive pulse is a low energy main drive pulse when the main drive pulse is changed to a low energy main drive pulse.

In addition, when the rotation detecting unit determines that the stepping motor has not been rotated by driving by any one of the main driving pulses, the control unit drives the correction driving pulse and then drives the energy from the main driving pulse. The main drive pulse may be changed to a larger main drive pulse.
In addition, when the rotation detecting unit determines that the stepping motor does not rotate by driving with any one of the main driving pulses, the control unit uses the correction driving pulse when the main driving pulse has the maximum energy. After driving, the main drive pulse may be changed to a main drive pulse having lower energy than the main drive pulse having the maximum energy.

  According to the present invention, in the analog electronic timepiece that controls the rotation of the stepping motor by the stepping motor control circuit, the stepping motor control circuit according to any one of the above is used as the stepping motor control circuit. An analog electronic watch is provided.

According to the motor control circuit of the present invention, driving with an appropriate main drive pulse makes it possible to reduce the drive with the correction drive pulse and save power.
Further, according to the analog electronic timepiece according to the invention, it is possible to reduce the driving by the correction driving pulse and to save power by driving by an appropriate main driving pulse.

FIG. 1 is a block diagram of an analog electronic timepiece according to an embodiment of the present invention, showing an example of an analog electronic wristwatch.
In FIG. 1, an analog electronic timepiece includes an oscillation circuit 101 that generates a signal of a predetermined frequency, a frequency dividing circuit 102 that divides the signal generated by the oscillation circuit 101 and generates a clock signal that serves as a time reference, and an electronic timepiece. A control circuit 103 that performs control such as control of each electronic circuit element that is configured and drive pulse change control, and a drive pulse selection circuit 104 that selects and outputs a drive pulse for motor rotation driving based on a control signal from the control circuit 103. have.

  The analog electronic circuit is also driven by a stepping motor 105 that is rotationally driven by a drive pulse from the drive pulse selection circuit 104, and a time hand that is rotationally driven by the stepping motor 105 (in the example of FIG. 1, hour hand 107, minute hand). 108, three types of second hand 109), rotation detection circuit 110 for detecting a rotation detection signal Vmax representing the rotation state from the stepping motor 105 at a predetermined detection time, and rotation indicating that the stepping motor 105 has rotated. When the rotation detection circuit 110 detects the detection signal Vmax, the rotation detection circuit 110 includes a detection section determination circuit 111 that determines in which section of the plurality of sections provided within the detection time the rotation detection signal Vmax is generated. ing.

  The rotation detection circuit 110 has the same configuration as the rotation detection circuit described in Patent Document 1, and detects a rotation detection signal Vmax exceeding a predetermined reference threshold voltage Vcomp when the stepping motor 105 rotates. When the motor 105 does not rotate, the reference threshold voltage Vcomp is set so that the rotation detection signal Vmax does not exceed the reference threshold voltage Vcomp.

The stepping motor 105 is a stepping motor having the configuration shown in FIG. In the present embodiment, as will be described later, a plurality of main drive pulses P10 to P1m having different energies and correction drives having larger energy than the main drive pulses P10 to P1m as drive pulses for driving the stepping motor 105 to rotate. Pulse P2 is used.
The oscillation circuit 101 and the frequency dividing circuit 102 constitute signal generating means, the analog display unit 106 constitutes time display means, and the rotation detection circuit 110 constitutes rotation detection means. The control circuit 103, the drive pulse selection circuit 104, the rotation detection circuit 110, and the detection interval determination circuit 111 constitute a control means.

FIG. 2 is a timing chart showing the operation of the analog electronic timepiece according to the embodiment of the invention, and is a timing chart when the stepping motor 105 is driven.
In FIG. 2, the rank n of the main drive pulse P1n has a plurality of ranks from the minimum value 0 to the maximum value m, and the larger the value of n, the greater the energy of the drive pulse (in this embodiment, the pulse width of the rectangular wave is Long) is configured.

  Further, the correction drive pulse P2 is configured to have larger energy (longer pulse width) than the main drive pulse P1m having the maximum energy. That is, the drive pulses P10, P1m, and P2 are configured such that the pulse widths satisfy P10 <P1m <P2. The main drive pulse P1n may have a comb-shaped chopping waveform, and the number of choppings and the duty ratio may be increased so that the energy of the pulse increases as the value of n increases.

  In FIG. 2, Vcomp is a reference threshold voltage that is a voltage reference for detecting whether or not the rotation is made by comparing with a rotation detection signal Vmax based on an induced voltage generated by the stepping motor 105. The reference threshold voltage Vcomp is set so that the rotation detection signal Vmax exceeds the reference threshold voltage Vcomp when the stepping motor 105 rotates, and the rotation detection signal Vmax does not exceed the reference threshold voltage Vcomp when the stepping motor 105 rotates. ing.

The time after driving the stepping motor by the drive pulse is divided into a mask time IT which is a time immediately after driving without detecting the rotation detection signal Vmax and a detection time which is a time for detecting the rotation detection signal Vmax after the mask time IT has elapsed. is doing.
In addition, the detection time is defined as follows: a predetermined time immediately after the lapse of the mask time IT is the first interval T1, a predetermined time after the first interval T1 is the second interval T2, and a predetermined time after the second interval T2 is the third interval T3. As shown, the detection time is divided into three sections, a first section T1 to a third section T3.

As a method for setting the detection sections T1 to T3, the first reference time and the second reference time after the first time are set according to a predetermined reference within the detection time, so that immediately after the mask time IT has elapsed. From the first reference time to the first reference time, the second reference time from the first reference time to the second reference time may be set as the second section T2, and a predetermined time from the second reference time may be set as the third section T3.
Although the details will be described later, the basic operation of the embodiment of the present invention will be described briefly. When the energy of the main drive pulse P1 is smaller than the load of the motor 105, the stepping motor 105 rotates slowly. The rotation detection signal Vmax indicating that the stepping motor 105 has rotated, that is, the rotation detection signal Vmax that exceeds the reference threshold voltage Vcomp that should be generated within the mask time IT is generated at an early time (first interval T1). To do.

Further, when the energy of the main drive pulse P1 is smaller than the load of the motor 105, if the rotation detection signal Vmax is not generated in the first section T1 as described above, the stepping motor 105 rotates slowly. A rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is generated in the third section T3.
Further, when the energy of the main drive pulse P1 is larger than the load of the motor 105, the stepping motor 105 rotates faster, so that the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is in the third section T3. It occurs in the second section T2 before.

  In the present embodiment, paying attention to the relationship between the generation timing of the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp and the energy of the main drive pulse P1 with respect to the load of the motor 105 as described above, the correction drive The main drive pulse P1 is controlled so that the drive by the pulse P2 is minimized.

In the present embodiment, when the rotation detection signal Vmax indicating that the motor 105 has rotated is detected in the first section T1 or the third section T3, the main drive pulse P1 is changed to the main drive pulse P1 having a large energy. (Rank up).
When the rotation detection signal Vmax is detected in the second section T2, in principle, the main drive pulse P1 is not changed, but the rotation detection signal Vmax is continuously generated a predetermined number of times by driving with the main drive pulse P1 having the same energy. When it is detected in the second section T2, it is determined that the drive energy is too large, and the main drive pulse P1 is changed to a main drive pulse with a small energy (rank down).
However, when the rank is lowered, the rank cannot be lowered when the main drive pulse is the main drive pulse P10 having the lowest energy. Therefore, the main drive pulse P1 is not changed and the next main drive pulse P10 is driven by the same main drive pulse P10.

  On the other hand, when the rotation detection signal Vmax indicating the rotation of the motor 105 is not detected in any of the first section T1 to the third section T3, that is, the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is detected within the detection time. If not detected, the main drive pulse P1 is changed to the main drive pulse P1 having a large energy after being driven by the correction drive pulse P2 by determining that it is not rotating (ranking up).

  However, when the main drive pulse P1 at the time of non-rotation is the main drive pulse P1m with the maximum energy, the main drive pulse P1m can no longer be rotated and the main drive with the maximum energy after the correction drive pulse P2 is driven. It is determined that driving with the pulse P1m is a waste of energy, and after driving with the correction driving pulse P2, the main driving pulse P1 (m−a) (a: rank-down number, 1 ≦ 1) having smaller energy than the main driving pulse P1m. The drive is changed to an arbitrary integer of a ≦ m.

  Thereafter, since it cannot be rotated by driving with the main driving pulse P1 (m-a), driving with the correction driving pulse P2 is performed. However, the main driving pulse is the main driving pulse P1 (m-a) with low energy. Therefore, energy loss can be suppressed to a small level. From the viewpoint of further reducing energy loss, the main drive pulse P10 having the lowest energy (a = m, that is, n = 0) is more preferable.

FIG. 3 is a flowchart showing operations of the stepping motor control circuit and the analog electronic timepiece according to the embodiment of the present invention.
Hereinafter, the operations of the stepping motor control circuit and the analog electronic timepiece according to the embodiment of the present invention will be described in detail with reference to FIGS.
In FIG. 1, an oscillation circuit 101 generates a reference clock signal having a predetermined frequency, and a frequency dividing circuit 102 divides the signal generated by the oscillation circuit 101 to generate a clock signal serving as a time reference, and a control circuit 103. Output to.

  The control circuit 103 counts the time signal and performs a time counting operation. First, the rank n of the main drive pulse P1n is set to 0 (steps S301 and S302 in FIG. 3), and the stepping motor is operated with the main drive pulse P10 having the minimum pulse width. A control signal is output so as to rotationally drive 105 (step S303).

  In response to the control signal from the control circuit 103, the drive pulse selection circuit 104 rotationally drives the stepping motor 105 with the main drive pulse P10. The stepping motor 105 is rotationally driven by the main drive pulse P10 to rotationally drive the time hands 107 to 109. Accordingly, when the stepping motor 105 rotates normally, the current time is displayed on the display unit 106 by the time hands 107 to 109 as needed.

  The rotation detection circuit 110 compares the rotation detection signal Vmax based on the induced voltage generated by the stepping motor 105 with a predetermined reference threshold voltage Vcomp, and the rotation detection signal Vmax exceeds the reference threshold voltage Vcomp. In other words, when it is determined that the stepping motor 105 is rotating, the detection interval determination circuit 111 determines which detection interval T1 to T3 within the detection time the detection time t of the rotation detection signal Vmax falls within. To do.

When the detection interval discriminating circuit 111 detects the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp in the first interval T1 (step S304), if the main drive pulse P1 at this time is not the maximum energy, FIG. As shown in the rank increase of (b1) and (b2), the control circuit 103 increases the main drive pulse P1 by one rank (steps S311 and SS310).
That is, in the present embodiment, when the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is detected in the first section T1 after the lapse of the mask time IT, it is determined that the drive energy is smaller than the load and the main drive Rank pulse P1 up. As a result, occurrence of a situation of driving with the correction drive pulse P2 is prevented.

The control circuit 103 does not change the rank of the main drive pulse P1 when the main drive pulse P1 is the main drive pulse with the maximum energy in the processing step S311 (step S312).
In FIG. 2B1, the rotation detection signal Vmax is generated in both the first section and the third section. In the present embodiment, the rotation detection signal Vmax that has exceeded the reference threshold voltage Vcomp first. In the case of FIG. 2 (b1), the rotation detection signal Vmax generated in the third section is ignored.

  When detecting that the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is not detected in the first interval T1 in the processing step S304, the detection interval determination circuit 111 detects the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp. Is detected in the second section T2 (step S305).

  In the processing step S305, when the section determination circuit 111 determines that the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is detected in the second section T2, the control circuit 103 determines that the main drive pulse P1 has the lowest energy. At P10, the main drive pulse P10 is maintained without changing the main drive pulse P1 (the rank is not changed in FIG. 2A), and the process returns to step S302 (steps S313 and S314).

  When the control circuit 103 determines in the processing step S313 that the main drive pulse P1 is not the lowest energy main drive pulse P10, the control circuit 103 counts a continuous number counter (not shown) that counts the number of continuous drives by the same main drive pulse P1. After adding 1 to the count value N, it is determined whether or not the driving by the main drive pulse P1 is continuously performed a predetermined number of times (160 times in the present embodiment) with reference to the count value N of the continuous number counter. (Step S316).

  In the processing step S316, the control circuit 103 is continuously driven by the main drive pulse P1 for the predetermined number of times (160 times in the present embodiment as described above) (that is, the count value of the continuous number counter). If N is determined to be 160), the main drive pulse P1 is lowered by one rank and is changed to a main drive pulse P1 having a small one-rank energy (rank down in FIG. 2 (c)), and the continuous number counter The count value N is reset to 0 (step S317).

If the control circuit 103 determines in step S316 that the main drive pulse P1 has not been continuously driven for the predetermined number of times (160 times), the control circuit 103 does not change the main drive pulse P1. The process returns to step S302 (S314).
That is, in the present embodiment, when the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is detected in the second section T2, in principle, the main drive pulse P1 is energy that can drive the load, and the correction drive pulse P2 Therefore, the main drive pulse P1 is not changed.

  However, when the same main drive pulse P1 can be continuously driven for a predetermined number of times, it is determined that the drive energy is too large compared to the load and excessive energy is consumed, and the main drive pulse P1 is By reducing the rank, power consumption is reduced. However, when the main drive pulse P1 is the lowest energy main drive pulse P10, the rank cannot be lowered, so that the current main drive pulse P10 is maintained without being changed.

  When detecting that the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is not detected in the second interval T2 in the processing step S305, the detection interval determination circuit 111 detects the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp. Is detected in the third section T3 (step S306).

If it is determined in process step S306 that the detection interval determination circuit 111 has detected the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp in the third interval T3, the process proceeds to process step S311 to perform the above-described processing (step S310, S312). In this case, in the processing step S310, the control circuit 103 increases the main drive pulse P1 by one rank, as shown in FIG.
That is, in the present embodiment, when the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is detected in the third section T3, it is determined that the rotation speed is slow and the drive energy is small compared to the load, and the main drive pulse Rank P1 up. As a result, occurrence of a situation of driving with the correction drive pulse P2 is prevented.

  In process step S306, when the detection interval determination circuit 111 determines that the rotation detection signal Vmax exceeding the reference threshold voltage Vcomp is not detected in the third interval T3, that is, exceeds the reference threshold voltage Vcomp within the detection time. When the rotation detection signal Vmax is not detected and the main drive pulse P1 at this time is not the main drive pulse P1m having the maximum energy, the control circuit 103 corrects the correction drive pulse P2 as shown in the rank-up in FIG. After forcibly driving the rotation, the main drive pulse P1 is increased by one rank, and the process returns to step S302 (steps S308 and 310).

When the control circuit 103 determines in the processing step S308 that the main driving pulse P1 is the main driving pulse P1m with the maximum energy, the control circuit 103 changes the main driving pulse P1 to the main driving pulse P1 that is ranked down by the predetermined rank number a, and returns to the processing step S302 ( Step S310). As a result, power consumption is suppressed when rotation cannot be achieved even with the maximum energy P1m.
Thereafter, by repeating the above process, the drive by the proper main drive pulse P1 is performed, and the drive by the correction drive pulse P2 is suppressed to a small extent.

As described above, according to the motor control circuit of the present embodiment, driving with the appropriate main drive pulse P1 can reduce the drive with the correction drive pulse P2 and save power. Become.
In addition, according to the analog electronic timepiece according to the present embodiment, driving with the proper main drive pulse P1 can reduce the drive with the correction drive pulse P2 to save power.

In the present embodiment, the pulse width is made different in order to change the energy of each main drive pulse P1, but the drive energy can also be changed by changing the pulse voltage or the like.
In addition to the time hand, the present invention can be applied to a stepping motor for driving a calendar or the like.
Moreover, although the example of the electronic timepiece has been described as an application example of the stepping motor, it can be applied to an electronic device using the motor.

The stepping motor control circuit according to the present invention is applicable to various electronic devices that use the stepping motor.
The electronic timepiece according to the present invention can be applied to various analog electronic timepieces, including analog electronic timepieces with various calendar functions such as an analog electronic wristwatch with a calendar function and an analog electronic table clock with a calendar function.

1 is a block diagram of an analog electronic timepiece according to an embodiment of the present invention. FIG. 6 is a timing diagram for explaining the operation of the stepping motor control circuit and the analog electronic timepiece according to the embodiment of the invention. It is a flowchart which shows the process of the stepping motor control circuit and analog electronic timepiece which concern on embodiment of this invention. It is a block diagram of the general stepping motor used for an analog electronic timepiece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Oscillator 102 ... Frequency divider 103 ... Control circuit 104 ... Drive pulse selection circuit 105 ... Stepping motor 106 ... Analog display 107 ... Hour hand 108 ... Minute hand 109 ... Second hand 110 ... Rotation detection circuit 111 ... Detection section discrimination circuit 201 ... Stator 202 ... Rotor 203 ... Rotor housing through holes 204, 205 ... Notches (inside notch)
206, 207 ... Notch (outer notch)
208 ... Magnetic core 209 ... Coils 210, 211 ... Saturable portion OUT1 ... First terminal OUT2 ... Second terminal

Claims (9)

A rotation detection signal generated by rotation of the stepping motor is detected at a detection time after a predetermined mask time has elapsed, and the stepping motor rotates when the rotation detection signal exceeds a predetermined reference threshold voltage within the detection time. Depending on the result of the determination by the rotation detection means and the rotation detection means, a plurality of main drive pulses having different energy from each other, or a correction drive pulse having higher energy than each of the main drive pulses. Comprising a control means for driving the stepping motor,
The detection time is divided into a first section, a second section after the first section, and a third section after the second section,
When the control means detects a rotation detection signal exceeding the predetermined reference threshold voltage in the first section when driven by any of the main drive pulses, the control means has a larger energy than the main drive pulse. A stepping motor control circuit which is driven by changing to a main drive pulse.   When the control means is driven by any one of the main drive pulses, and when the rotation detection signal exceeding the predetermined reference threshold voltage is detected in the third section, the control means has larger energy than the main drive pulse. 2. The stepping motor control circuit according to claim 1, wherein the stepping motor control circuit is driven by changing to a main drive pulse.   When the control means detects a rotation detection signal exceeding the predetermined reference threshold voltage in the first section or the third section when driven by any one of the main drive pulses, the main drive pulse is the largest. 3. The stepping motor control circuit according to claim 1, wherein the main drive pulse is not changed in the case of energy.   The control means does not change the main drive pulse when it is driven by any one of the main drive pulses and detects a rotation detection signal exceeding the predetermined reference threshold voltage in the second section. The stepping motor control circuit according to any one of claims 1 to 3, wherein the stepping motor control circuit is provided.   When the rotation detecting signal exceeding the predetermined reference threshold voltage is continuously detected a predetermined number of times in the second section, the control means changes the main drive pulse to a main drive pulse having a small energy and drives the rotation detection signal. The stepping motor control circuit according to claim 4.   6. The stepping motor according to claim 5, wherein, when the main drive pulse is changed to a main drive pulse having a low energy, the control means does not change when the main drive pulse is a main drive pulse having the lowest energy. Control circuit.   When the rotation detecting means determines that the stepping motor has not been rotated by driving with any of the main drive pulses, the control means has a higher energy than the main drive pulse after being driven by the correction drive pulse. The stepping motor control circuit according to claim 1, wherein the stepping motor control circuit is changed to a main drive pulse.   When the rotation detecting means determines that the stepping motor has not been rotated by driving with any one of the main drive pulses, the control means is driven with the correction drive pulse when the main drive pulse has the maximum energy. 8. The stepping motor control circuit according to claim 7, wherein the stepping motor control circuit is changed to a main driving pulse having a smaller energy than the main driving pulse having the maximum energy. In an analog electronic timepiece that controls the rotation of a stepping motor by a stepping motor control circuit,
9. An analog electronic timepiece using the stepping motor control circuit according to claim 1 as the stepping motor control circuit.

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