JP2011075462A - Stepping motor control circuit and analog electronic clock - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform drive control by a proper drive pulse by accurately discriminating drive remaining power. <P>SOLUTION: A rotation detection circuit 110 detects the rotation state of a stepping motor 105 according to whether or not an induction signal VRs exceeds a reference threshold voltage Vcomp1 for rotation state detection in a rotation detection section T comprising detection sections T1-T3. A detection time discrimination circuit 111 detects lengths of the detection sections T1-T3 y setting them based on an intersection of the induction signal VRs detected by the rotation detection circuit 110 and a reference threshold voltage Vcomp2 for detection section setting. A control circuit 103 controls the drive of the stepping motor 105 by either of a plurality of main drive pulses P1 having mutually different energy, respectively, or by a correction drive pulse P2 having larger energy than the main drive pulse P1 according to rotation states of the detection sections T1-T3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  As a control method of the stepping motor, when the stepping motor is driven by a main drive pulse, it detects whether or not it has rotated by detecting an induced signal generated by the free vibration of the stepping motor. Accordingly, a correction drive method is used in which the main drive pulse is changed to a different drive width and driven, or forcibly rotated by a correction drive pulse having a pulse width larger than that of the main drive pulse ( For example, see Patent Document 1.)

In Patent Document 2, when detecting the rotation of the stepping motor, in addition to detecting the level of the induced signal, means for comparing and determining the detection time with the reference time is provided, and the stepping motor is driven to rotate by the main drive pulse P11. Thereafter, when the induced signal falls below a predetermined reference threshold voltage Vcomp, the correction drive pulse P2 is output, and the next main drive pulse P1 is changed to the main drive pulse P12 having larger energy than the main drive pulse P11 and driven. When the detection time when rotating with the main drive pulse P12 is earlier than the reference time, the main drive pulse P12 is changed from the main drive pulse P12 to the main drive pulse P11, thereby rotating with the main drive pulse P1 corresponding to the load during driving.
Thereby, the rotation detection accuracy can be improved and current consumption can be reduced as compared with the invention described in Patent Document 1.

  However, the peak generation time of the induced signal due to the free vibration of the rotor tends to be earlier when the driving energy is larger than the load, and delayed when the driving energy is smaller. In addition, there is a problem that peak voltage variation increases in proportion to the passage of time due to the influence of the train wheel load fluctuation. In addition, since there is load variation in each movement, there is a problem that it is difficult to perform stable drive pulse control based on the peak generation time of the induced signal.

Japanese Patent Publication No. 61-15385 WO2005 / 119377

  The present invention has been made in view of the above problems, and an object of the present invention is to accurately determine the remaining drive force and perform drive control using an appropriate drive pulse.

According to the present invention, the rotation detection means detects the induced signal generated by the rotation of the stepping motor in the rotation detection section starting immediately after the end of driving by the drive pulse, and detects the rotation state of the stepping motor based on the induced signal. In accordance with the detection result of the induction signal in each detection section, the detection section setting means for setting a plurality of detection sections constituting the rotation detection section to a length based on the induction signal detected by the rotation detection means, A stepping motor comprising: control means for driving and controlling the stepping motor by any one of a plurality of main drive pulses having different energy from each other or a correction drive pulse having a larger energy than each of the main drive pulses. A control circuit is provided.
The detection section setting means sets a plurality of detection sections constituting the rotation detection section to a length based on the induced signal detected by the rotation detection means. According to the detection result of the induced signal in each detection section, the control means uses the stepping motor by one of a plurality of main drive pulses having different energy from each other or a correction drive pulse having a larger energy than each of the main drive pulses. Is controlled.

  Here, the rotation detection means detects the rotation status of the stepping motor according to whether the induced signal exceeds a reference threshold voltage for rotation status detection within the rotation detection interval, and the detection interval setting means The length of each detection section is set on the basis of the intersection of the induced signal detected by the rotation detection means and the reference threshold voltage for detection section setting, and the control means depends on the rotation state in each detection section. The stepping motor may be driven and controlled by any one of a plurality of main drive pulses having different energy from each other or a correction drive pulse having a larger energy than each of the main drive pulses.

  The rotation detection section is divided into a first detection section immediately after the end of driving by the main drive pulse, a second detection section that follows the first detection section, and a third detection section that follows the second detection section. And the detection section setting means sets the length of each detection section on the basis of the intersection of the induced signal detected by the rotation detection means and the reference threshold voltage for detection section setting. Based on the detection patterns of the first to third detection sections, the stepping motor is driven and controlled by one of a plurality of main drive pulses having different energy from each other or a correction drive pulse having energy larger than each of the main drive pulses. You may comprise as follows.

  Further, the detection interval setting means determines the length of the first detection interval based on a comparison result between the induced signal generated within a predetermined time immediately after the end of driving by the main drive pulse and the interval threshold reference threshold voltage. It is determined whether or not to change, and in the case of changing, the end of the first detection interval is determined from a point at which the induced signal first intersects with the interval setting reference threshold voltage or a point at which the induction signal intersects first. You may comprise so that it may set to the point which time passed.

Further, the detection section setting means continuously detects an induction signal that does not exceed the section setting reference threshold voltage after the rotation detection section detects the induction signal that exceeds the section setting reference threshold voltage at the predetermined time. In some cases, the length of the first detection section may be changed.
In addition, the detection interval setting means sets, as an end point of the second detection interval, a point after a predetermined time has elapsed from the point where the induced signal crossing the interval setting reference threshold voltage is detected after the first detection interval has elapsed. You may comprise.

  According to the present invention, in the analog electronic timepiece having a stepping motor that rotationally drives the time hand and a stepping motor control circuit that controls the stepping motor, the stepping motor control circuit according to any one of the above An analog electronic timepiece using a stepping motor control circuit is provided.

According to the stepping motor control circuit of the present invention, it is possible to accurately determine the remaining driving force and perform drive control using an appropriate drive pulse.
Further, according to the analog electronic timepiece according to the invention, it is possible to accurately determine the remaining driving force and perform driving control with an appropriate driving pulse, and thus it is possible to perform an accurate time measuring operation.

1 is a block diagram of an analog electronic timepiece according to an embodiment of the present invention. It is a block diagram of the stepping motor used for the analog electronic timepiece which concerns on embodiment of this 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 determination chart explaining the operation of the stepping motor control circuit and the analog electronic timepiece according to the embodiment of the present 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.

Hereinafter, a motor control circuit and an analog electronic timepiece according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals.
FIG. 1 is a block diagram of an analog electronic timepiece using a motor control circuit according to an embodiment of the present invention, and shows 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. , A stepping motor 105 that is rotationally driven by the drive pulse from the drive pulse selection circuit 104, and a time hand that is rotationally driven by the stepping motor 105 to display the time (in the example of FIG. 1, three of the hour hand 107, the minute hand 108, and the second hand 109). The analog display unit 106 having the type) and the induced signal representing the rotation state from the stepping motor 105 The rotation detection circuit 110 that detects in the rotation detection section T, the time when the rotation detection circuit 110 detects the induced signal that exceeds a predetermined reference threshold voltage Vcomp and the detected detection section are compared, and which detection signal is detected. A detection time discriminating circuit 111 that discriminates whether or not it has been detected in the section is provided. In the present embodiment, the rotation detection section T for detecting the rotation state of the stepping motor 105 is divided into three detection sections.

  The rotation detection circuit 110 detects an induced signal generated by free vibration after the stepping motor 105 is driven to rotate by the same principle as that of the rotation detection circuit described in Patent Document 1. The threshold voltage includes a rotation condition detection reference threshold voltage Vcomp1 for detecting the rotation condition of the stepping motor 105 and a detection interval setting reference threshold voltage Vcomp2 for setting a detection interval.

The rotation condition detection reference threshold voltage Vcomp1 is set so that a rotation condition such as rotation or non-rotation can be determined by a pattern of a detection interval in which an induced signal exceeding the rotation condition detection reference threshold voltage Vcomp1 is generated. Yes.
Further, the reference threshold voltage Vcomp2 for setting the detection interval is such that the position where the rotor magnetic pole axis intersects the horizontal magnetic path direction of the stepping motor 105 due to the free vibration of the rotor immediately after the end of driving by the main drive pulse P1 and the vibration direction of the rotor. This is a reference voltage for detecting the position of inversion.

The rotation detection circuit 110 notifies the detection time discriminating circuit 111 when the induction signal VRs that exceeds the rotation condition detection reference threshold voltage Vcomp1 is generated among the induction signals VRs generated by the stepping motor 105, and the induction signal VRs. The point at which the signal VRs has changed across the detection interval setting reference threshold voltage Vcomp2 (the point at which the induced signal VRs has continuously changed from a level greater than the detection interval setting reference threshold voltage Vcomp2 to a lower level, A point at which VRs continuously changes from a level smaller than a detection threshold setting reference threshold voltage Vcomp2 to a larger level is detected and notified to the detection time determination circuit 111.
The detection time determination circuit 111 sets the length of the detection sections T1 to T3 based on the notification from the rotation detection circuit 110, and uses the set detection sections T1 to T3 to detect the reference threshold voltage Vcomp1 for rotation status detection. And a point where the induced signal VRs crosses the detection threshold setting reference threshold voltage Vcomp2 is detected and notified to the control circuit 103.

As will be described later, the control circuit 103 detects, from the detection time discriminating circuit 111, a detection interval in which an induced signal VRs exceeding the rotation condition detection reference threshold voltage Vcomp1 is generated, and the induced signal VRs is a detection interval setting reference threshold voltage Vcomp2. In response to the information on the points changed by intersecting with each other, various processes such as a pattern determination process and a drive pulse control process are performed.
The oscillation circuit 101 and the frequency dividing circuit 102 constitute signal generating means, and the analog display unit 106 constitutes time display means. The rotation detection circuit 110 constitutes rotation detection means, and the detection time discrimination circuit 111 constitutes detection interval setting means. In addition, the control circuit 103, the drive pulse selection circuit 104, the rotation detection circuit 110, and the detection section determination circuit 111 constitute a control unit.

FIG. 2 is a configuration diagram of the stepping motor 105 used in the embodiment of the present invention, and shows an example of a time stepping motor generally used in an analog electronic timepiece.
In FIG. 2, the stepping motor 105 includes a stator 201 having a rotor housing through hole 203, a rotor 202 rotatably disposed in the rotor housing 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). A plurality of (two in this embodiment) notch portions (outer notches) 206 and 207 are provided at positions facing each other across the rotor accommodating through hole 203 at the outer end portion of the stator 201 formed of a magnetic material. Is provided. 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 through hole 203 for accommodating the rotor has a circular hole shape in which a plurality of (two in the present embodiment) half-moon-shaped notches (inner notches) 204 and 205 are integrally formed at the opposing portion of the through hole having a circular outline. It is configured.

  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. 2, in other words, a line segment connecting the notches 204 and 205 with the magnetic pole axis A of the rotor 202. Is stably stopped at a position (angle θ0 position) perpendicular to the angle. An XY coordinate space centered on the rotation axis (rotation center) of the rotor 202 is divided into four quadrants (first quadrant I to fourth quadrant IV).

  Now, a rectangular-wave drive pulse is supplied from the drive pulse selection circuit 104 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 arrow in FIG. When a current i flows in the direction, a magnetic flux is generated in the stator 201 in the direction of the broken arrow. As a result, the saturable portions 210 and 211 are saturated to increase the magnetic resistance, and then the rotor 202 is moved in the forward direction (counterclockwise in FIG. 2) due to the interaction between the magnetic pole generated in the stator 201 and the magnetic pole of the rotor 202. The magnetic pole axis A is stably stopped at the angle θ1 position. Note that the rotation direction for causing the stepping motor 105 to rotate and perform a normal operation (in this embodiment, an electronic timepiece, a hand movement operation) is a forward direction, and the reverse is the reverse direction.

Next, from the drive pulse selection circuit 104, a drive pulse having a reverse polarity rectangular wave is supplied to the terminals OUT1 and OUT2 of the coil 209 (the first terminal OUT1 side is connected to the negative electrode so that the drive polarity is opposite to that of the drive). When the second terminal OUT2 side is the positive electrode) and a current is passed in the direction indicated by the arrow in FIG. Thereby, the saturable portions 210 and 211 are first saturated, and then the rotor 202 rotates 180 degrees in the same direction (positive direction) as described above due to the interaction between the magnetic pole generated in the stator 201 and the magnetic pole of the rotor 202. The magnetic pole axis A stably stops at the angle θ0 position.
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. In the present embodiment, a plurality of main drive pulses P10 to P1m and correction drive pulses P2 having different energy (that is, different energy ranks) are used as drive pulses.

FIG. 3 is a timing chart when the stepping motor 105 is driven by the main drive pulse P1 in this embodiment, and shows the load size, the rotational position of the rotor 202, the pattern, and the pulse control operation.
In FIG. 3, P1 is a section in which the rotor 202 is rotationally driven by the main drive pulse P1, and ac is a section representing a rotation region of the rotor 202 due to free vibration after the drive of the main drive pulse P1 is stopped. A predetermined time immediately after the end of driving by the main drive pulse P1 is a first detection interval T1, a predetermined time following the first detection interval T1 is a second detection interval T2, and a predetermined time following the second detection interval is third detected. The section is T3. In this way, the entire detection section T starting immediately after the end of driving by the main drive pulse P1 is divided into a plurality of sections (three detection sections T1 to T3 in the present embodiment). In the present embodiment, there is no mask section that is a period during which no induced signal VRs is detected.

When the space region where the magnetic pole axis A of the rotor 202 is located by the rotation of the rotor 202 is divided into the first quadrant I to the fourth quadrant IV, the first section T1 to the third section T3 are expressed as follows. be able to.
That is, in the state where the load is normally driven (normal load) (the state shown in FIG. 3 (i)), the second section T2 and the third section T3 rotate in the reverse direction of the rotor 202 in the third quadrant III (region c). ) To determine. Here, the normal load means a load that is driven in a normal state, and in the present embodiment, the state in which the time hand is driven is a normal load.

Further, in a state where a small load is increased with respect to the normal load (load increment is small) (state of FIG. 3 (ii)), the first section T1 rotates in the positive direction of the rotor 202 in the second quadrant II (region a). The second section T2 and the third section T3 are sections for determining the reverse rotation (region c) of the rotor 202 in the third quadrant III.
After the induction signal VRs having the same polarity as the detection interval setting reference threshold voltage Vcomp2 is generated in the region a, the induction signal VRs having the opposite polarity to the detection interval setting reference threshold voltage Vcomp2 is changed in the region b. Since the detection interval setting reference threshold voltage Vcomp2 is set to a voltage substantially equal to the ground, the point D intersecting the detection interval setting reference threshold voltage Vcomp2 indicates that the magnetic pole axis A of the rotor 202 is in the horizontal direction of the magnetic circuit. It coincides with the timing of passing through (horizontal magnetic path direction).

Further, after an induced signal having a polarity opposite to that of the detection section setting reference threshold voltage Vcomp2 is generated in the region b, the induced signal VRs having the same polarity as the detection section setting reference threshold voltage Vcomp2 is changed in the region c. A point E that intersects the detection threshold value setting reference threshold voltage Vcomp2 coincides with the timing at which the magnetic pole axis A of the rotor 202 reaches the maximum amplitude angle.
In the present embodiment, the detection timing T1 to T3 is changed every time the main driving pulse is driven by detecting the above-mentioned timing, so that the erroneous determination of the rotation detection is eliminated and the rotation is reliably determined. .

In the normal signal, the induced signal VRs generated by the free rotation vibration of the stepping motor 105 causes the rotation angle of the rotor 202 after the main drive pulse P1 is cut off to pass the second quadrant II. The induced signal VRs exceeding Vcomp1 does not appear in the first detection interval T1, but appears after the second detection interval T2. When the remaining rotation force is large, the rotor 202 rotates faster and appears in the second detection section. When the remaining rotation force is not large, the rotor 202 rotates later and appears in the third detection section.
Further, when there is no surplus power in the rotation of the rotor 202, the rotor rotational vibration after the main drive pulse P1 is interrupted appears in the region of the second quadrant II (region a in FIG. 2), and the induced signal VRs is the first. It shows a state where it appears in the section T1 and the remaining rotational force has decreased.
Based on such characteristics, drive control is performed with an appropriate drive pulse by accurately determining the drive capacity.

As described above, the reference threshold voltage Vcomp1 for detecting the rotation state is a reference threshold voltage for determining the voltage level of the induced signal VRs generated in the stepping motor 105 in order to determine the rotation state of the stepping motor 105. When the rotor 202 performs a certain fast operation, such as when the rotor 105 rotates, the induced signal VRs exceeds the reference threshold voltage Vcomp1 for detecting the rotation state, and the rotor 202 remains constant as when the rotor 202 does not rotate. When the fast operation is not performed, the rotation condition detection reference threshold voltage Vcomp1 is set so that the induced signal VRs does not exceed the rotation condition detection reference threshold voltage Vcomp1.
For example, in the state where the load increment is small in FIG. 3 (ii), the induced signal VRs generated in the region a is generated in the first detection interval T1, and the induced signal generated in the region c is the second detection interval T2 and the third detection interval. Occurs in section T3. The induced signal VRs generated in the region b is generated across the first section T1 and the second section T2, but is not detected because it is generated in the reverse polarity to the reference threshold voltage Vcomp1 for detecting the rotation state.

  Further, the reference threshold voltage Vcomp2 for setting the detection interval is set such that the magnetic pole axis A of the rotor 202 is moved in the horizontal magnetic path direction of the stepping motor 105 (X-axis direction in FIG. ) And a point E where the vibration direction of the rotor 202 first reverses, and in order to enable the detection of the point D and the low-level induced signal VRs, It is set to a voltage (substantially zero V in the present embodiment) smaller than the detection reference threshold voltage Vcomp1.

  In the state where the load increment is small in FIG. 3 (ii), the point D is the point where the induced signal VRs first intersects the detection interval setting reference threshold voltage Vcomp2, in other words, the induced signal VRs is the detection interval setting reference. This is a point that changes from a voltage exceeding the threshold voltage Vcomp2 to a voltage not exceeding the threshold voltage Vcomp2. The point E is a point where the induced signal VRs intersects the detection interval setting reference threshold voltage Vcomp2 for the second time, in other words, an intersection detected first after the first detection interval T1 elapses, or the induced signal VRs. Changes from a voltage not exceeding the detection interval setting reference threshold voltage Vcomp2 to a voltage exceeding it.

  FIG. 4 is a determination chart summarizing the drive pulse control operation in the present embodiment. In each detection section T1 to T3, when the rotation detection circuit 110 detects the induced signal VRs exceeding the rotation condition detection reference threshold voltage Vcomp1, the determination value is “1”, and the rotation detection circuit 110 determines the rotation condition detection reference threshold. A case where the induced signal VRs exceeding the voltage Vcomp1 cannot be detected is represented as a determination value “0”. “1/0” represents that the determination value may be “1” or “0”.

  As shown in FIG. 4, the rotation detection circuit 110 detects the presence / absence of the induced signal VRs exceeding the rotation condition detection reference threshold voltage Vcomp1, and the detection time determination circuit 111 determines the detection timing of the induced signal VRs ( 4 based on the determination value of the first detection interval T1, the determination value of the second detection interval T2, the determination value of the third detection interval T3), and stored in the storage means in the control circuit 103. The control circuit 103 and the drive pulse selection circuit 104 are driven by a pulse-up for changing the main drive pulse P1 to the main drive pulse P1 having a large energy, a pulse-down for changing to the main drive pulse P1 having a small energy, or a correction drive pulse P2. The stepping motor 105 is rotationally controlled by performing drive pulse control such as the above.

  For example, in the case of the pattern (1/0, 0, 0), the control circuit 103 determines that the stepping motor 105 is not rotating (non-rotating) and drives the stepping motor 105 with the correction driving pulse P2. After controlling the drive pulse selection circuit 104, the drive pulse selection circuit 104 is controlled so as to change to the main drive pulse P1 that is upgraded by one rank in the next drive.

  In the case of the pattern (1/0, 0, 1), the control circuit 103 has rotated the stepping motor 105 but increased a large load with respect to the normal load (large load increment), and does not rotate at the next drive. The drive pulse selection circuit determines that the rotation is likely to become (a marginal rotation) and changes the drive to the main drive pulse P1 that has been upgraded one rank in advance during the next drive without performing the drive by the correction drive pulse P2. 104 is controlled.

In the case of the pattern (0, 1, 1/0), the control circuit 103 determines that the stepping motor 105 rotates, the load is a normal load, and the drive energy has a margin (surplus rotation; FIG. 3 (i)). Thus, the drive pulse selection circuit 104 is controlled so as to change to the main drive pulse P1 that is lowered by one rank in the next drive.
In the case of the pattern (1, 1, 1/0), the control circuit 103 determines that the stepping motor 105 rotates, the load is a small load increment, and the drive energy is appropriate (rotation with no margin; FIG. 3 (ii)). Thus, the drive pulse selection circuit 104 is controlled to drive without changing the main drive pulse P1 at the next drive.

By the way, even if the rotation detection section T is divided into three detection sections T1 to T3, and the length of each detection section T1 to T3 is fixed to a certain time width, the rotation state is detected. By suppressing the driving by P2, it is possible to save power and drive control.
However, when the rotational speed of the rotor 202 decreases, such as when a needle with a large moment of inertia is attached, when the power supply voltage decreases, when the viscosity of oil increases at low temperatures, or when the load increases due to calendar load, etc. If the generation of the induced signal VRs is delayed, the induced signal VRs generated only in the first detection section T1 may be detected not only in the first detection section T1 but also in the second detection section T2. At this time, even if the next induced signal VRs appears in the third detection section T3, since the pattern (1, 1, 1) is detected, it is erroneously determined that the rotation is not enough, and the rank of the main drive pulse P1 is maintained. It will end up. Therefore, there is a problem in that when the next drive is non-rotation and the non-rotation induction signal VRs is high and it is erroneously determined to be rotation, the timepiece operation of the timepiece is delayed.

  In addition, the generation of the induced signal VRs is significantly delayed, and the induced signal VRs generated in the second detection section T2 may be detected not in the second detection section T2 but in the third detection section T3. For example, a pattern (0, 1, 0) may be detected as a pattern (0, 0, 1). In this case, the detection of the third detection section T3 erroneously determines that the rank has been increased, and the drive energy has been increased, but the current consumption has increased more than necessary, and the battery life has been shortened. There is a problem.

In the embodiment of the present invention, each detection is performed based on the point where the induced signal VRs intersects the detection interval setting reference threshold voltage Vcomp2 every time the main drive pulse P1 is driven (for example, every 1 second). By changing the lengths of the sections T1 to T3, it is possible to accurately detect the rotation state when driven by the main drive pulse P1.
FIG. 5 is a flowchart showing the process of the present embodiment, and shows a section change process for changing the length of the detection sections T1 to T3.

Hereinafter, the section change process in the present embodiment will be described with reference to FIGS.
The rotation detection circuit 110 notifies the detection time discriminating circuit 111 when the induction signal VRs that exceeds the rotation condition detection reference threshold voltage Vcomp1 is generated among the induction signals VRs generated by the stepping motor 105, and the induction signal VRs. A point (points D and E in FIG. 3) at which the signal VRs changes crossing the detection interval setting reference threshold voltage Vcomp2 is detected and notified to the detection time determination circuit 111.

  The detection time discriminating circuit 111 receives information on the point at which the induced signal VRs has changed across the detection interval setting reference threshold voltage Vcomp2 from the rotation detection circuit 110, and receives a predetermined time T1a (from the end of the main drive pulse P1 drive). After the induced signal VRs exceeding the detection threshold setting reference threshold voltage Vcomp2 is generated within a predetermined time shorter than the first detection interval T1, the induced signal does not exceed the detection threshold setting reference threshold voltage Vcomp2 following this. It is determined whether or not a point D where the induced signal VRs has crossed the detection threshold setting reference threshold voltage Vcomp2 due to the occurrence of VRs has been detected (step S501).

  When the detection time discriminating circuit 111 determines in the processing step S501 that the intersection D has been detected within the predetermined time T1a, the detection time determination circuit 111 sets the intersection D as the end time of the first detection interval T1 and rotates in the first detection interval T1. After determining whether or not the induced signal VRs exceeding the detection reference threshold voltage Vcomp1 is detected, the process proceeds to processing step S504 (step S502). Note that, from the viewpoint of preventing erroneous detection in consideration of variations in the generation time of the induced signal VRs, the end time of the first detection section T1 may be set after a predetermined time from the intersection D.

  When it is determined in the processing step S501 that the intersection D has not been detected within the predetermined time T1a, the detection time determination circuit 111 ends the detection processing within the predetermined time T1a without changing the first detection interval. The determination value of one detection section T1 is set to “0”, and the process proceeds to processing step S504 (step S503). If it is determined in process step S501 that the intersection D has not been detected within the predetermined time T1a, the control circuit 103 may be configured to set the end point of the first detection section T2 to a predetermined initial value. Good.

  Next, in the processing step S504, the detection time determination circuit 111 continues after the induction signal VRs that does not exceed the detection threshold value setting reference threshold voltage Vcomp2 is generated until the third detection interval T3 is ended. It is determined whether or not the point E where the induced signal VRs crosses the detection interval setting reference threshold voltage Vcomp2 by detecting the induced signal VRs exceeding the detection interval setting reference threshold voltage Vcomp2 is detected.

When the detection time determination circuit 111 determines that the intersection E has been detected before the end of the third detection section T3 in the processing step S504, the detection time determination circuit 111 sets the end time of the second detection section T2 after a predetermined time has elapsed from the intersection E. Set (step S505). As a result, the point at which a predetermined time has elapsed from the point at which the induced signal VRs that crosses the section setting reference threshold voltage Vcomp2 after the first detection section T1 has elapsed is set as the end point E of the second detection section T2. Become. Since the length of the rotation detection section T is fixed, the end point of the third detection section T3 does not change even when the end points of the first detection section T1 and the second detection section T2 are changed.
The detection time determination circuit 111 determines whether or not the induced signal VRs exceeding the reference threshold voltage Vcomp1 for detecting the rotation state is detected in the detection sections T2 and T3 set in this way.

  If the detection time determination circuit 111 determines in the processing step S504 that the intersection E has not been detected before the end of the third detection interval T3, the detection time determination circuit 111 does not change the end point of the second detection interval T2. The detection up to the third detection interval T3 is terminated, and the determination values of the second detection interval T2 and the third detection interval T3 are set to “0” (step S506). If it is determined in the processing step S504 that the intersection E has not been detected before the end of the third detection section T3, the control circuit 103 sets the end point of the second detection section T2 to a predetermined initial value. You may comprise.

The detection time discriminating circuit 111 sets the first detection interval T1 to the third detection interval T3 as described above, and whether the induced signal VRs exceeds the reference threshold voltage Vcomp1 for detecting the rotation state in each detection interval T1 to T3. To detect. The control circuit 103 performs pulse control with reference to the determination chart of FIG. 4 based on the determination value patterns in the first detection interval T1 to the third detection interval T3. Thereafter, the above process is repeated every time the main drive pulse P1 is used for driving.
Accordingly, for example, when the load increases in the state where the load increment is small in FIG. 3 (ii) and becomes the state where the load increment is large in FIG. 3 (iii), the reference threshold for detecting the rotation state in the first detection section T1. In order to set the detection interval so that the first detection interval T1 ends after the elapse of a predetermined time from the point D that does not exceed the detection interval setting reference threshold voltage Vcomp2 after exceeding the voltage Vcomp1, the first detection interval T1 The generated induced signal VRs is not erroneously detected in the second detection section T2, and the control circuit 103 can normally determine the pattern (1, 0, 1). Therefore, it is possible to prevent the main drive pulse P1 from being accidentally maintained in the rank and to pulse up normally.

  Further, for example, when the load increases in the state where the load increment is small in FIG. 3 (ii) and becomes the state where the load increment is large in FIG. 3 (iv), the reference threshold voltage for detecting the rotation state in the first detection section T1. After exceeding Vcomp1, the detection interval is set so that the first detection interval T1 ends after a lapse of a predetermined time from the point D that does not exceed the detection interval setting reference threshold voltage Vcomp2, and the detection interval is detected in the second detection interval T2. In order to set the detection interval so that the second detection interval T2 ends after a lapse of a predetermined time from the intersection E exceeding the detection interval setting reference threshold voltage Vcomp2 after the setting reference threshold voltage Vcomp2 is not exceeded. No erroneous detection occurs in the third detection section T3, and the control circuit 103 can normally determine the pattern (1, 1, 0). Therefore, it is possible to prevent the main drive pulse P1 from being erroneously ranked up and to maintain the rank normally.

  As described above, according to the stepping motor control circuit according to the embodiment of the present invention, the detection time discriminating circuit 111 has the rotation detection section T having a length based on the induced signal VRs detected by the rotation detection circuit 110. Since the control circuit 103 determines the rotation state based on the induced signal patterns in the plurality of detection sections T1 to T3, the control circuit 103 accurately determines the drive remaining capacity and uses the appropriate drive pulse. Drive control can be performed. Since it is possible to suppress driving by the correction driving pulse P2, power saving can be achieved.

  Even when the rotor speed decreases, such as when rotating a time hand with a large moment of inertia, when the power supply voltage drops, when the viscosity of oil increases at low temperatures, or when driving a large load such as a calendar load, etc. The induction signal VRs immediately after the end of driving is reliably detected in the first detection section T1, and it is possible to eliminate the erroneous determination that the rank should be determined to be rank maintenance. As a result, the non-rotation is not erroneously detected as rotation, and the timepiece can be moved reliably.

In addition, the induced signal VRs after the reversal of the rotation direction is reliably detected in the second detection section T2, and it is possible to eliminate erroneous determination of rank up even though the driving force is sufficient. Therefore, the consumption current is increased more than necessary, and the battery life is not shortened, and the battery life can be ensured.
In addition, according to the analog electronic timepiece according to the present invention, it becomes possible to accurately determine the drive remaining capacity and perform drive control with an appropriate drive pulse, so that it is possible to perform accurate timekeeping operation, Power saving is possible.

In the above-described embodiment, the pulse width is changed 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. Alternatively, the main drive pulse P1 may have a comb-shaped chopping waveform, and the drive energy of the main drive pulse P1 may be changed by changing the number of choppings and the duty.
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.

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 time 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 (7)

A rotation detecting means for detecting an induction signal generated by rotation of the stepping motor in a rotation detection section starting immediately after the end of driving by the drive pulse, and detecting a rotation state of the stepping motor based on the induction signal;
Detection interval setting means for setting a plurality of detection intervals constituting the rotation detection interval to a length based on an induced signal detected by the rotation detection means;
Depending on the detection result of the induced signal in each detection section, the stepping motor is driven and controlled by one of a plurality of main drive pulses having different energy from each other or a correction drive pulse having energy larger than each main drive pulse. And a stepping motor control circuit comprising a control means. The rotation detection means detects the rotation state of the stepping motor according to whether or not the induced signal has exceeded a reference threshold voltage for rotation state detection within the rotation detection section,
The detection section setting means sets the length of each detection section on the basis of the intersection between the induced signal detected by the rotation detection means and the reference threshold voltage for detection section setting,
The control means controls the stepping motor by one of a plurality of main drive pulses having different energy from each other or a correction drive pulse having energy larger than each of the main drive pulses according to the rotation state in each detection section. 2. The stepping motor control circuit according to claim 1, wherein driving control is performed. The rotation detection section is divided into a first detection section immediately after the end of driving by the main drive pulse, a second detection section that follows the first detection section, and a third detection section that follows the second detection section. The detection interval setting means sets the length of each detection interval with reference to the intersection of the induced signal detected by the rotation detection means and the reference threshold voltage for detection interval setting,
Based on the detection patterns of the first to third detection sections, the control means uses any one of a plurality of main drive pulses having different energy from each other or a correction drive pulse having a larger energy than each of the main drive pulses. The stepping motor control circuit according to claim 2, wherein the stepping motor is driven and controlled.   The detection section setting means changes the length of the first detection section based on a comparison result between the induced signal generated within a predetermined time immediately after the end of driving by the main drive pulse and the section setting reference threshold voltage. If the change is to be made, the end of the first detection interval is determined at the end of the first detection interval from the point at which the induced signal first intersects the interval setting reference threshold voltage or from the first intersection. 4. The stepping motor control circuit according to claim 3, wherein the stepping motor control circuit is set at the point.   The detection section setting means, when the rotation detection means continuously detects an induced signal that does not exceed the section setting reference threshold voltage after detecting the induced signal that exceeds the section setting reference threshold voltage at the predetermined time. The stepping motor control circuit according to claim 4, wherein a length of the first detection section is changed.   The detection interval setting means sets, as an end point of the second detection interval, a point after a predetermined time has elapsed from a point at which an induced signal crossing the interval setting reference threshold voltage is detected after the first detection interval has elapsed. The stepping motor control circuit according to claim 3, wherein In an analog electronic timepiece having a stepping motor that rotationally drives a time hand and a stepping motor control circuit that controls the stepping motor,
An analog electronic timepiece using the stepping motor control circuit according to any one of claims 1 to 6 as the stepping motor control circuit.

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