JP2020159818A - Stepping motor controller, timepiece, and steeping motor control method - Google Patents

Abstract

To improve the accuracy of correcting the rotation position of a rotor when subjected to an external force that rotates the rotor.SOLUTION: A stepping motor controller 100 controls a stepping motor 151 that comprises a rotor for causing a pointer 155 to rotate clockwise in a normal direction and causing the pointer 155 to rotate counterclockwise in a reverse direction, a coil for generating a magnetic flux due to that a drive current flows, and a stator for applying the magnetic flux generated by the coil to the rotor. The stepping motor controller 100 comprises an external force detection unit for detecting on the basis of the state of a voltage induced in the coil that an external force other than a force due to the magnetic flux is applied to the rotor, and a drive control unit for supplying a drive current for rotating the rotor to the coil when it is detected by the external force detection unit that an external force has been applied to the rotor.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to a stepping motor control device, a clock, and a stepping motor control method.

When driving a stepping motor used to drive a pointer of a timepiece, an external force such as a drop impact may be applied to the rotor of the stepping motor. In this case, the rotation position of the rotor changes due to an external force, so that the rotation position of the rotor may deviate from the original control position. In this regard, Patent Document 1 discloses a technique of applying a braking force to the rotor to suppress the rotation of the rotor when an external force is applied to the rotor.

JP-A-2017-96950

However, according to the prior art as described in Patent Document 1, there is a problem that a sufficient braking force may not be obtained.
In view of the above-mentioned problems, the embodiment of the present invention is a stepping motor control device and a clock capable of improving the accuracy of correction of the rotation position of the rotor when an external force for rotating the rotor is received in the rotation control of the stepping motor. And to provide a stepping motor control method.

In the stepping motor control device according to one aspect of the present invention, a drive current flows through a rotor that rotates a pointer in a forward rotation direction that rotates a pointer clockwise and a rotor that rotates the pointer in a reverse direction that is a direction opposite to the normal rotation direction. A stepping motor control device for controlling a stepping motor including a coil that generates a magnetic flux by the coil and a stator that applies a magnetic flux generated by the coil to the rotor, and a state of a voltage induced in the coil. Based on the above, an external force detecting unit that detects that an external force other than the force due to the magnetic flux is applied to the rotor, and a rotor that rotates when the external force detecting unit detects that the external force is applied to the rotor. It is provided with a drive control unit that supplies a drive current to be driven to the coil.

The stepping motor control device according to one aspect of the present invention detects whether the rotation direction of the rotor due to the external force is the forward rotation direction or the reverse rotation direction based on the state of the voltage induced in the coil. The drive control unit further includes a rotation direction detection unit, which coincides with the rotation direction detected by the rotation direction detection unit among the drive current driven in the forward rotation direction and the drive current driven in the reverse rotation direction. A drive current that rotates the rotor in the direction is supplied to the coil.

In the stepping motor control device according to one aspect of the present invention, in the rotation direction detection unit, the rotation direction of the rotor due to the external force is positive based on the order of appearance of the voltage induced at either end of the coil. It detects whether it is the rolling direction or the reverse direction.

In the stepping motor control device according to one aspect of the present invention, in the rotation direction detection unit, the rotation direction of the rotor due to the external force is the forward rotation direction based on the appearance time width of the voltage induced in the coil. It is detected whether the direction is the reverse direction.

In the stepping motor control device according to one aspect of the present invention, the rotor is magnetized to at least two poles, an N pole and an S pole, and has a relative positional relationship between the reference direction of the stator and the magnetic pole direction of the rotor. Further, based on the above, the rotation position detecting unit for detecting the direction of the magnetic pole of the rotor rotated by the external force is further provided, and the drive control unit is based on the direction of the magnetic pole of the rotor detected by the rotation position detecting unit. , Control the state of the drive current supplied to the coil.

The stepping motor control device according to one aspect of the present invention further includes an inspection current supply unit that supplies an inspection current for rotating the rotor to the coil after the drive control unit supplies the drive current to the coil. The rotation position detection unit detects the rotation position of the magnetic pole of the rotor based on the state of the voltage induced in the coil after the inspection current is supplied to the coil by the inspection current supply unit.

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

In the stepping motor control method according to one aspect of the present invention, a driving current is passed through a rotor that rotates a pointer in a forward rotation direction that rotates a pointer clockwise and a rotor that rotates the pointer in a reverse direction that is a direction opposite to the normal rotation direction. It is a control method of a stepping motor including a coil that generates a magnetic flux by the coil and a stator that applies the magnetic flux generated by the coil to the rotor, and is based on the state of the voltage induced in the coil. An external force detecting step of detecting that an external force other than a force is applied to the rotor, and a drive current for rotating the rotor when the external force is detected in the rotor is detected in the coil. Has a drive control step and supplies to.

According to an embodiment of the present invention, it is possible to provide a stepping motor control device, a clock, and a stepping motor control method capable of improving the accuracy of correction of the rotation position of the rotor when an external force for rotating the rotor is received. ..

It is a figure which shows an example of the structure of the timepiece which concerns on embodiment. It is a figure which shows an example of the motor drive circuit and the stepping motor which concerns on embodiment. It is a figure which shows an example of the signal generated in each of the two terminals of a coil when rotating the rotor which concerns on embodiment, and the gate signal input to the gate of a transistor to generate these signals. FIG. 5 is a diagram showing an example of a state in which the rotor according to the embodiment rotates one step in the normal rotation direction from the state shown in FIG. 2 and vibrates freely. This is an example of a drive pulse, an induced voltage, and a correction drive pulse in the case shown in FIG. 4, and a gate signal input to the gate of the transistor to generate these three signals. It is a figure which shows an example of the case where the rotor is rotated one step in the forward rotation direction from the state shown in FIG. 2, and then the impact of rotating the rotor one step in the forward rotation direction is applied to the timepiece according to the embodiment. FIG. 6 is a diagram showing an example of an induced voltage generated at each of the gate signal input to the gate of the transistor and the two terminals of the coil in the case shown in FIG. It is a figure which shows an example of the case where the rotor is rotated one step in the forward rotation direction from the state shown in FIG. 2, and then the impact of rotating the rotor one step in the reverse direction is applied to the timepiece according to the embodiment. It is a figure which shows an example of the induced voltage generated in each of the two terminals of a coil in the case shown in FIG. It is a figure which shows an example of the detection pattern of the rotation direction by the needle jump rotation direction detection circuit of this embodiment. It is a figure which shows an example of the behavior of a rotor in the case of a normal rotation impact in this embodiment. It is a figure which shows an example of the behavior of a rotor in the case of a reverse impact in this embodiment. It is a figure which shows an example of the operation of the stepping motor control device of this embodiment. It is a figure which shows an example of the state which the external force in the forward rotation direction is applied to the rotor of this embodiment. It is a figure which shows an example of the waveform when the external force in the forward rotation direction is applied to the rotor of this embodiment. It is a figure which shows an example of the state which the external force in the reverse direction is applied to the rotor of this embodiment. It is a figure which shows an example of the waveform when the external force in the reverse direction is applied to the rotor of this embodiment.

An example of the clock 1 according to the embodiment will be described with reference to the figure.
FIG. 1 is a diagram showing an example of a configuration of a clock according to an embodiment.

[Functional configuration of clock 1]
The clock 1 includes a stepping motor control device 100, a stepping motor 151, a clock case 152, an analog display unit 153, a movement 154, and a pointer 155.

The watch case 152 is a housing that houses the stepping motor control device 100, the stepping motor 151, the analog display unit 153, the movement 154, and the pointer 155.

The analog display unit 153 is a dial on which a scale is engraved. The movement 154 is a mechanical mechanism for driving each part of the watch 1. The pointer 155 includes an hour hand, a minute hand, a second hand and other hands.

The stepping motor control device 100 includes an oscillation circuit 101, a frequency dividing circuit 102, a control circuit 103, a main drive pulse generation circuit 104, a correction drive pulse generation circuit 105, a motor drive circuit 106, and a rotation detection circuit 113. , Rotation correction circuit 116, needle skip correction drive pulse generation circuit 117, needle skip suppression pulse generation circuit 118, polarity check pulse generation circuit 119, polarity detection circuit 120, needle skip detection circuit 121, needle skip rotation. It includes a direction detection circuit 122.

The oscillation circuit 101 generates a signal having a predetermined frequency and transmits it to the frequency dividing circuit 102. The frequency dividing circuit 102 divides the signal received from the oscillation circuit 101 to generate a clock signal that serves as a reference for timekeeping, and transmits the clock signal to the control circuit 103. The control circuit 103 transmits control signals to each part of the clock 1 based on the clock signals and the like received from the frequency dividing circuit 102, and controls these operations.

The main drive pulse generation circuit 104 generates a drive current Idrv that drives the stepping motor 151 based on the control signal received from the control circuit 103, and outputs the drive current Idrv to the motor drive circuit 106. In the following description, the drive current Idrv that drives the stepping motor 151 is also described as a main drive pulse. The main drive pulse is a comb-shaped voltage pulse output for rotating the rotor 202 of the stepping motor 151, which will be described later, in one step, that is, in the forward rotation direction of 180 degrees.
In the following description, the rotation direction of the rotor 202 when the pointer 155 is rotated clockwise is also referred to as a forward rotation direction. Further, the rotation direction of the rotor 202 when the pointer 155 is rotated counterclockwise is also referred to as a reverse direction.

The correction drive pulse generation circuit 105 generates a correction drive current Icr that drives the stepping motor 151 based on the control signal received from the control circuit 103, and outputs the correction drive current Icr to the motor drive circuit 106. In the following description, the correction drive current Icr that drives the stepping motor 151 is also described as a correction drive pulse. The correction drive pulse is a voltage pulse that is output when the rotor 202 of the stepping motor 151, which will be described later, does not rotate in the forward rotation direction due to the main drive pulse. Since the duty ratio is larger than that of the main drive pulse, the main drive pulse Greater energy than. The correction drive pulse drives the stepping motor 151 with a torque larger than that of the main drive pulse.

[Structure of motor drive circuit 106 and stepping motor 151]
FIG. 2 is a diagram showing an example of a motor drive circuit and a stepping motor according to the embodiment. The motor drive circuit 106 includes a transistor TP1, a transistor TP2, a transistor TP3, a transistor TP4, a transistor TN1, a transistor TN2, a detection resistor Rs1, a detection resistor Rs2, a terminal ОUT1, and a terminal ОUT2.

Transistor TP1, transistor TP2, transistor TP3 and transistor TP4 are P-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), which turn on when a low-level gate signal is received and receive a high-level gate signal. Then it turns off. 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 circuit 106. The low-level potential is 0 V or a potential equal to VSS, which is a reference voltage.

The sources of the transistor TP1, the transistor TP2, the transistor TP3, and the transistor TP4 are electrically connected to each other, and VDD, which is the power supply voltage of the motor drive circuit 106, is supplied. The drain of the transistor TP3 is electrically connected to one end of the detection resistor Rs1. Further, the drain of the transistor TP1, the drain of the transistor TN1, and the other end of the detection resistor Rs1 are electrically connected to the terminal ОUT1. The drain of the transistor TP4 is electrically connected to one end of the detection resistor Rs2. Further, the drain of the transistor TP2, the drain of the transistor TN2, and the other end of the detection resistor Rs2 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. Further, the terminal ОUT1 and the terminal ОUT2 are connected to an input terminal of a comparator (not shown). Further, a reference voltage Vcomp, which will be described later, is input to the reference input terminal of this comparator.

[Structure of stepping motor 151]
The stepping motor 151 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 a magnetic core 208, one end thereof is connected to the terminal ОUT1, and the other end is connected to the terminal ОUT2. The coil 209 generates a magnetic flux by passing a drive current Idrv.

The terminal ОUT1 of the coil 209 is connected to the input terminal of the first comparator (not shown). A reference voltage Vcomp is supplied to the reference voltage input terminal of the first comparator. The first comparator outputs a comparison result between the voltage of the terminal ОUT1 (or the terminal ОUT2) applied to the input terminal and the reference voltage Vcomp. The terminal ОUT2 is connected to the input terminal of the second comparator (not shown). Since the configuration of the second comparator is the same as that of the first comparator, the description thereof will be omitted.

The stator 201 is 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 rotates the pointer 155 in the forward rotation direction for rotating the pointer 155 clockwise and the pointer 155 in the reverse rotation direction which is 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.

[Example of drive waveform of stepping motor 151]
FIG. 3 is a diagram showing an example of a signal generated at each of the two terminals of the coil when the rotor according to the embodiment is rotated and a gate signal input to the gate of the transistor to generate these signals.

When the magnetic pole axis A of the rotor 202 is stationary in a state orthogonal to the line segment connecting the inner notch 204 and the inner notch 205, the motor drive circuit 106 is, for example, transistor TP1, transistor TP2, transistor TP3, and transistor TP4. , Outputs a gate signal to the transistor TN1 and the transistor TN2. Here, TP1 in the figure shows the gate signal of the transistor TP1, TP2 shows the gate signal of the transistor TP2, TP3 shows the gate signal of the transistor TP3, and TP4 shows the gate signal of the transistor TP4. Further, TN1 represents the gate signal of the transistor TN1, and TN2 represents the gate signal of the transistor TN2.

The motor drive circuit 106 reverses the direction of the drive current Idrv supplied to the coil 209 according to the direction of the magnetic pole axis A at the stop position of the rotor 202, thereby rotating the rotor 202 in a certain direction (for example, a normal rotation direction). Rotate to.

As an example, driving in the forward rotation direction will be described. When the motor drive circuit 106 supplies a drive pulse between the first terminal OUT1 and the second terminal OUT2 of the coil 209, a magnetic flux is generated in the stator 201. As a result, the saturable portions 210 and 211 are saturated to increase the magnetic resistance, and then the interaction between the magnetic poles generated in the stator 201 and the magnetic poles of the rotor 202 causes the rotor 202 to rotate 180 degrees counterclockwise in FIG. It rotates and stops stably. By this rotation of about 180 degrees, the pointer 155 of the clock 1 can move a specified amount of one scale. The specified amount of operation may be referred to as one step. A train wheel having an appropriate reduction ratio is appropriately arranged between the rotor 202 and the pointer 155 so as to perform the specified amount of operation. In one example of this embodiment, the pointer 155 moves by one second by the operation of one step.

When the rotor 202 is in the state shown in FIG. 2, when the motor drive circuit 106 supplies the drive pulse shown at time t1 to time t2 in FIG. 3 between the first terminal OUT1 and the second terminal OUT2 of the coil 209, the stator A magnetic flux is generated in 201. Due to this magnetic flux, the rotor 202 rotates 180 degrees counterclockwise in FIG. 2 and stops stably.
Further, when the rotor 202 is in a state of being rotated by approximately 180 degrees from the state of FIG. 2, the motor drive circuit 106 has a drive pulse shown at time t3 to time t4 of FIG. 3 (that is, a drive pulse of time t1 to time t2). Is a drive pulse of opposite polarity) is supplied between the first terminal OUT1 and the second terminal OUT2 of the coil 209, and the stator 201 generates a magnetic flux opposite to the magnetic flux generated at time t1 to time t2. .. As a result, the saturable portions 210 and 211 are first saturated, and then the rotor 202 is rotated 180 degrees counterclockwise in FIG. 2 due to the interaction between the magnetic poles generated in the stator 201 and the magnetic poles of the rotor 202, and is stable. Stop at.
By supplying signals having different polarities (alternating signals) to the coil 209 in this way, the rotor 202 is continuously rotated by approximately 180 degrees counterclockwise in FIG.

[Rotor rotation detection and correction drive pulse output when rotor is stopped]
Next, the mechanism of rotation detection of the rotor 202 by the rotation detection circuit 113 will be described with reference to FIGS. 4 and 5.
FIG. 4 is a diagram showing an example of a state in which the rotor according to the embodiment rotates one step in the normal rotation direction from the state shown in FIG. 2 and vibrates freely.
FIG. 5 is an example of a drive pulse, an induced voltage, and a correction drive pulse in the case shown in FIG. 4, and a gate signal input to the gate of the transistor in order to generate these three signals. In the following description, the first quadrant, the second quadrant, the third quadrant and the IV quadrant separated by the X direction and the Y direction shown in FIG. 4 are used. Further, as shown in FIG. 4, a horizontal magnetic pole is provided at the boundary (X-axis in the figure) between the region composed of the I and II quadrants and the region composed of the III and IV quadrants. positioned.

The motor drive circuit 106 outputs the drive pulse P1 shown in FIG. 5 to the terminal ОUT2 by outputting a gate signal similar to the gate signal shown at time t1 to time t2 in FIG. As a result, a drive current flows through the paths of VDD, transistor TP1, terminal ОUT1, coil 209, terminal ОUT2, transistor TN2, and VSS, and magnetic flux is generated in coil 209. The north and south poles of the rotor 202 repel each of the north and south poles generated in the stator 201 by the magnetic flux, so that the rotor 202 has loci r1, locus r2, and locus r3 shown in FIG. , It rotates from the θ ₀ direction to the θ ₁ direction.

The locus r1 exceeds the maximum point of the magnetic potential formed by the inner notch 205 from the state where the rotor 202 points the north pole in the direction of θ ₀ , and reaches the boundary between the second quadrant and the third quadrant. It shows the situation. Further, the drive pulse P1 is output while the rotor 202 continues to rotate represented by the locus r1. The locus r2 has a clockwise angular velocity from a state in which the north pole of the rotor 202 is located at the boundary between the second quadrant and the third quadrant to a state in which the rotor 202 points the north pole in the direction of θ _1. It shows how it rotates until it reaches zero. The locus r3 shows how the rotor 202 rotates counterclockwise after the angular velocity in the clockwise direction becomes zero. After that, the rotor 202 repeats the rotation in the clockwise direction and the rotation in the counterclockwise direction until the kinetic energy is exhausted.

The motor drive circuit 106 refers to, for example, transistor TP1, transistor TP2, transistor TP3, transistor TP4, transistor TN1 and transistor TN2 while the rotor 202 continues to rotate as represented on locus r2 or locus r3. The gate signal shown in is output.

As a result, the transistor TP1 and the transistor TP4 are turned on by receiving the low-level gate signal. Transistor TP3 receives a high level gate signal and turns off. Transistor TN1 and transistor TN2 receive a low-level gate signal and turn off. Then, the transistor TP2 receives the comb-shaped gate signal and repeats on and off. Further, this comb-shaped gate signal is called a chopper signal.

In this case, as shown in FIG. 5, the voltage of the terminal ОUT1 becomes high level, and while the rotor 202 continues to rotate represented by the locus r2, a spike-like voltage response higher than the high level is output to the terminal ОUT2. Will be done. This spike-shaped voltage response is shown in FIG. 5, and is a response obtained by amplifying and detecting the induced current Irs1 flowing in the same direction as the drive current by a chopper signal, and the magnitude of the voltage is large. It is limited to a certain level or less by the parasitic diode of the transistor TP2. The process of amplifying the signal by the chopper signal is called chopper amplification.

Further, as shown in FIG. 5, while the rotor 202 continues to rotate represented by the locus r3, a spike-shaped voltage response lower than the high level is output to the terminal ОUT2. These spike-shaped voltage responses are shown in FIG. 5, and are responses obtained by amplifying and detecting the induced current Irs2 flowing in the direction opposite to the drive current by a chopper signal. The rotation detection circuit 113 determines that the rotor 202 has rotated one step when the absolute value of these spike-shaped voltage responses exceeds the reference voltage Vcomp (not shown). That is, when the rotor 202 normally rotates in the forward rotation direction without rotating in the forward rotation direction or the reverse rotation direction due to an impact such as dropping, the absolute value exceeds the reference voltage Vcomp each time the drive pulse is output. A spiked voltage response is detected once. On the other hand, as shown in FIG. 5, the rotation detection circuit 113 determines that the rotor 202 is not rotating when the absolute value of these spike-shaped voltage responses is equal to or less than the reference voltage Vcomp.
The reference voltage Vcomp referred to here is, for example, as shown in FIG. 5, a potential equal to 0V or VSS, which is a reference voltage.

When it is determined that the rotor 202 is rotating, the control circuit 103 continues the normal control. On the other hand, when it is determined that the rotor 202 is not rotating, the control circuit 103 controls the correction drive pulse generation circuit 105 and the motor drive circuit 106, and for example, the correction drive pulse P2 or the correction drive pulse shown in FIG. The Pr is output to the terminal ОUT2.

Specifically, the motor drive circuit 106 outputs the gate signal shown in FIG. 5 to, for example, the transistor TP1, the transistor TP2, the transistor TP3, the transistor TP4, the transistor TN1 and the transistor TN2. As a result, the transistor TP1 receives the low-level gate signal and turns on. Transistor TP2, transistor TP3 and transistor TP4 receive a high level gate signal and turn off. Transistor TN1 receives a low level gate signal and turns off. Transistor TN2 receives a high level gate signal and turns on. In this case, as shown in FIG. 5, the voltage of the terminal ОUT1 becomes high level, and the correction drive pulse P2 is output to the terminal ОUT2.

Alternatively, the motor drive circuit 106 outputs the gate signal shown in FIG. 5 to, for example, the transistor TP1, the transistor TP2, the transistor TP3, the transistor TP4, the transistor TN1 and the transistor TN2. As a result, the transistor TP1 receives the low-level gate signal and turns on. Transistor TP3 and transistor TP4 receive a high level gate signal and turn off. Transistor TN1 receives a low level gate signal and turns off. The transistor TP2 and the transistor TN2 receive a comb-shaped gate signal and repeat on and off. In this case, as shown in FIG. 5, the voltage of the terminal ОUT1 becomes high level, and the comb-shaped correction drive pulse Pr is output to the terminal ОUT2.

[Needle skipping detection when impacted]
FIG. 6 shows an example of a case where an impact of rotating the rotor by one step in the forward rotation direction and then rotating the rotor by one step in the forward rotation direction is applied to the timepiece according to the embodiment from the state shown in FIG. It is a figure.
FIG. 7 is a diagram showing an example of an induced voltage generated at each of the gate signal input to the gate of the transistor and the two terminals of the coil in the case shown in FIG.
In the following description, the rotation of the rotor 202 by an external force applied to the watch 1 (for example, an impact force due to dropping) is also referred to as hand skipping. The hand skip detection circuit 121 detects the rotation of the rotor 202 due to the external force applied to the clock 1.

The motor drive circuit 106 outputs the gate signal shown in FIG. 7 to, for example, the transistor TP1, the transistor TP2, the transistor TP3, the transistor TP4, the transistor TN1 and the transistor TN2.

As a result, the transistor TP3 and the transistor TP4 are turned on by receiving the low-level gate signal. Further, the transistor TN1 and the transistor TN2 receive the low level gate signal and turn off. Further, the transistor TP1 and the transistor TP2 receive a periodic gate signal and repeat on and off. This periodic gate signal is called a chopper signal. Further, for example, as shown in FIG. 7, the periodic gate signal has a period of 244 microseconds and a high level time of 30.5 microseconds per cycle.

While the transistor TP1 and the transistor TP2 are on, the first induced current Irs3 and the second induced current Irs4 shown in FIG. 7 pass through the transistor TP1, the terminal ОUT1, the coil 209, the terminal ОUT2, and the transistor TP2. Flow. On the other hand, while the transistor TP1 and the transistor TP2 are off, the first induced current Irs3 and the second induced current Irs4 shown in FIG. 7 are the transistor TP3, the detection resistor Rs1, the terminal ОUT1, the coil 209, the terminal ОUT2, and the detection. It flows through the second path through the resistor Rs2 and the transistor TP4.

The impedance in the path increases at the moment when the transistor TP1 and the transistor TP2 are switched from on to off, that is, at the moment when the path through which the first induced current Irs3 or the second induced current Irs4 flows switches from the first path to the second path. As a result, as shown in FIG. 7, a spike-shaped voltage response is output to the terminals ОUT1 and ОUT2.

When the absolute value of these spike-shaped voltage responses exceeds the reference voltage Vcomp, the needle skip detection circuit 121 determines that the rotor 202 has rotated due to an impact such as a drop applied to the watch 1, and these spikes. When the absolute value of the voltage response is equal to or less than the reference voltage Vcomp, it is determined that the rotor 202 is not rotating due to the impact. The reference voltage Vcomp referred to here is, for example, an arbitrary voltage between VSS, which is 0 V or a reference voltage, and VDD, which is a power supply voltage of the motor drive circuit 106, as shown in FIG.

That is, the needle skip detection circuit 121 (external force detection unit) detects that an external force other than the force due to the magnetic flux is applied to the rotor 202 based on the state of the voltage induced in the coil 209.

The needle jump rotation direction detection circuit 122 determines the direction in which the rotor 202 is rotated. Specifically, in the needle jump rotation direction detection circuit 122, when the absolute value of the first induced voltage exceeds a predetermined threshold value before the absolute value of the second induced voltage, the rotor 202 is impacted in the forward rotation direction. Judge that it has rotated. Further, the needle jump rotation direction detection circuit 122 determines that the rotor 202 has rotated in the reverse direction due to an impact when the absolute value of the second induced voltage exceeds a predetermined threshold value before the absolute value of the first induced voltage. To do. Here, the first induced voltage is a voltage at which the first induced current Irs3 shown in FIG. 6 is passed through the coil 209. The second induced voltage is a voltage at which the second induced current Irs4 shown in FIG. 6 is passed through the coil 209. Further, the first induced current Irs3 is a current flowing in the same direction as the drive current. The second induced current Irs4 is a current flowing in the direction opposite to the drive current.

That is, the needle jump rotation direction detection circuit 122 (rotation direction detection unit) determines whether the rotation direction of the rotor 202 due to the external force is the forward rotation direction or the reverse rotation direction based on the state of the voltage induced in the coil 209. To detect.

The locus r4 of FIG. 6 shows how the rotor 202 rotates in the normal rotation direction from the state where the north pole is directed in the direction of θ ₁ to the boundary between the IV quadrant and the I quadrant. In this case, the first induced current Irs3 flows in the same direction as the drive current Idrv shown in FIG. As shown in FIG. 7, the first induced voltage corresponding to the first induced current Irs3 is output to the terminal ОUT1 as a spike-like voltage response lower than the high level, and the spike-like voltage response higher than the high level. Is output to the terminal ОUT2. Further, as shown in FIG. 7, a part of the first induced voltage output to the terminal ОUT1 exceeds the reference voltage Vcomp. The first induced voltage output to the terminal ОUT2 is limited to a certain level or less by the parasitic diode of the transistor TP2.

The locus r5 of FIG. 6 is outside after the rotor 202 points the north pole in the direction of the boundary between the IVth quadrant and the Ith quadrant and the rotor 202 points the north pole in the direction of θ _0. It shows how it rotates to the front of the notch 206. In this case, the second induced current Irs4 flows in the direction opposite to the drive current Idrv shown in FIG. As shown in FIG. 7, the second induced voltage corresponding to the second induced current Irs4 is output to the terminal ОUT2 as a spike-like voltage response lower than the high level, and the spike-like voltage response higher than the high level. Is output to the terminal ОUT1. Further, as shown in FIG. 7, a part of the second induced voltage output to the terminal ОUT2 exceeds the reference voltage Vcomp. The second induced voltage output to the terminal ОUT1 is limited to a certain level or less by the parasitic diode of the transistor TP1.

The locus r6 in FIG. 6 shows how the rotor 202 rotates clockwise after the angular velocity in the counterclockwise direction becomes zero. In this case, the first induced current Irs3 flows in the same direction as the drive current Idrv shown in FIG. 2, as in the case where the rotor 202 is in the rotational state represented by the locus r4 shown in FIG. As shown in FIG. 7, the first induced voltage corresponding to the first induced current Irs3 is output to the terminal ОUT1 as a spike-like voltage response lower than the high level, and the spike-like voltage response higher than the high level. Is output to the terminal ОUT2. Further, as shown in FIG. 7, a part of the first induced voltage output to the terminal ОUT1 exceeds the reference voltage Vcomp. The first induced voltage output to the terminal ОUT2 is limited to a certain level or less by the parasitic diode of the transistor TP2.

As described above, when an impact of rotating the rotor by one step in the forward rotation direction and then rotating the rotor by one step in the forward rotation direction from the state shown in FIG. 2 is applied to the clock according to the embodiment, it is absolutely absolute at first. The first induced voltage whose value exceeds the reference voltage Vcomp is output to the terminal ОUT1, then the second induced voltage whose absolute value exceeds the reference voltage Vcomp is output to the terminal ОUT2, and the absolute value exceeds the reference voltage Vcomp again. The induced voltage is output to terminal ОUT1. The needle jump rotation direction detection circuit 122 determines that the needle jump impact in the normal rotation direction has been received when the first induced voltage exceeding the reference voltage Vcomp is output to the terminal ОUT1. The needle jump rotation direction detection circuit 122 may determine that the needle jump in the normal rotation direction has been impacted based on the output of the first induced voltage exceeding the reference voltage Vcomp to the terminal ОUT1. , Based on all of the series of outputs as described above, it may be determined that the impact of needle jump in the forward rotation direction has been received.

FIG. 8 is a diagram showing an example of a case where an impact of rotating the rotor by one step in the forward rotation direction and then rotating the rotor by one step in the reverse direction is applied to the timepiece according to the embodiment from the state shown in FIG. Is.
FIG. 9 is a diagram showing an example of the induced voltage generated at each of the two terminals of the coil in the case shown in FIG.

The motor drive circuit 106 outputs, for example, a gate signal similar to the gate signal shown in FIG. 7 to the transistor TP1, the transistor TP2, the transistor TP3, the transistor TP4, the transistor TN1 and the transistor TN2. As a result, these six transistors operate in the same manner as described with reference to FIGS. 6 and 7. Further, the hand skip detection circuit 121 determines whether or not the rotor 202 has rotated due to an impact such as a drop applied to the clock 1 in the same manner as described with reference to FIGS. 6 and 7.

The needle jump rotation direction detection circuit 122 determines the direction in which the rotor 202 is rotated. The locus r7 of FIG. 8 shows how the rotor 202 rotates in the reverse direction from the state where the north pole is directed in the direction of θ ₁ to the boundary between the third quadrant and the second quadrant. In this case, the second induced current Irs4 flows in the direction opposite to the drive current Idrv shown in FIG. As shown in FIG. 9, the second induced voltage corresponding to the second induced current Irs4 is output to the terminal ОUT2 as a spike-like voltage response lower than the high level, and the spike-like voltage response higher than the high level. Is output to the terminal ОUT1. Further, as shown in FIG. 9, the second induced voltage output to the terminal ОUT2 partially exceeds the reference voltage Vcomp, but since the angular range of the locus r7 is narrow, the range exceeds the reference voltage Vcomp. Is getting narrower. The second induced voltage output to the terminal ОUT1 is limited to a certain level or less by the parasitic diode of the transistor TP1.

The locus r8 of FIG. 8 is a clock from a state in which the rotor 202 points the north pole in the direction of the boundary between the third quadrant and the second quadrant to a state in which the rotor 202 points the north pole in the direction of θ _0. It shows how it rotates until the angular velocity around it becomes zero. In this case, the first induced current Irs3 flows in the same direction as the drive current Idrv shown in FIG. As shown in FIG. 9, the first induced voltage corresponding to the first induced current Irs3 is output to the terminal ОUT1 as a spike-like voltage response lower than the high level, and the spike-like voltage response higher than the high level. Is output to the terminal ОUT2. Further, as shown in FIG. 9, a part of the first induced voltage output to the terminal ОUT1 exceeds the reference voltage Vcomp. The first induced voltage output to the terminal ОUT2 is limited to a certain level or less by the parasitic diode of the transistor TP2.

The locus r9 in FIG. 8 shows how the rotor 202 rotates counterclockwise after the angular velocity in the clockwise direction becomes zero. In this case, the second induced current Irs4 flows in the direction opposite to the drive current Idrv shown in FIG. 2, as in the case where the rotor 202 is in the rotational state represented by the locus r7 shown in FIG. As shown in FIG. 9, the second induced voltage corresponding to the second induced current Irs4 is output to the terminal ОUT2 as a spike-like voltage response lower than the high level, and the spike-like voltage response higher than the high level. Is output to the terminal ОUT1. Further, as shown in FIG. 9, the second induced voltage of the second terminal OUT2 does not exceed Vcomp, and the second induced voltage output to the first terminal OUT1 is limited to a certain level or less by the parasitic diode of the transistor TP1. ..

As described above, when an impact of rotating the rotor one step in the forward rotation direction and then rotating the rotor one step in the reverse direction from the state shown in FIG. 2 is applied to the clock according to the embodiment, the absolute value is first applied. The second induced voltage exceeding the reference voltage Vcomp is output to the terminal ОUT2, then the first induced voltage whose absolute value exceeds the reference voltage Vcomp is output to the terminal ОUT1, and then the absolute value of the second induced voltage is the reference. Do not exceed the voltage Vcomp. The needle jump rotation direction detection circuit 122 determines that the needle jump in the reverse direction has been impacted when a second induced voltage exceeding the reference voltage Vcomp is output to the terminal ОUT2. The needle jump rotation direction detection circuit 122 may determine that the needle jump in the reverse direction has been impacted based on the output of the second induced voltage exceeding the reference voltage Vcomp to the terminal ОUT2. Based on the entire series of outputs as described above, it may be determined that the impact of needle jump in the reverse direction has been received.

FIG. 10 is a diagram showing an example of a rotation direction detection pattern by the needle jump rotation direction detection circuit 122 of the present embodiment. The needle jump rotation direction detection circuit 122 detects the rotation direction of the rotor 202 based on the appearance patterns of the induced voltage generated at the terminal ОUT1 and the induced voltage generated at the terminal ОUT2.
The appearance pattern of the induced voltage changes depending on the relative relationship between the rotation position of the rotor 202 (that is, the direction of the magnetic pole axis A) and the rotation direction of the rotor 202 due to an external force. 10 (A) to 10 (D) show an example of the appearance pattern of the induced voltage.
FIG. 10A shows the appearance pattern of the induced voltage when the rotor 202 rotates in the forward rotation direction due to an external force when the magnetic pole axis A is in the direction from the I to the III quadrant.
FIG. 10B shows an appearance pattern of the induced voltage when the rotor 202 is rotated in the reverse direction by an external force when the magnetic pole axis A is in the direction from the I to the III quadrant.
FIG. 10C shows the appearance pattern of the induced voltage when the rotor 202 is rotated in the forward rotation direction by an external force when the magnetic pole axis A is in the direction from the III quadrant to the I quadrant.
FIG. 10D shows the appearance pattern of the induced voltage when the rotor 202 is rotated in the reverse direction by an external force when the magnetic pole axis A is in the direction from the III quadrant to the I quadrant.

The needle jump rotation direction detection circuit 122 detects the rotation direction of the rotor 202 based on the appearance order of the induced voltage or the appearance time width of the induced voltage. A specific example of detecting the rotation direction by the needle jump rotation direction detection circuit 122 will be described.

[Detection of needle jump rotation direction (Part 1: Detection based on the order of appearance of induced voltage)]
In the needle jump rotation direction detection circuit 122 (rotation direction detection unit), the rotation direction of the rotor 202 due to an external force is the forward rotation direction or the reverse rotation direction based on the appearance order of the voltage induced at either end of the coil 209. Is detected.
In the case of the example shown in FIG. 10 (A), in the range r21, a large negative induced voltage is generated at the terminal ОUT1, and a positive induced voltage is generated at the terminal ОUT2. In the range r22, a positive induced voltage is generated at the terminal ОUT1 and a large negative induced voltage is generated at the terminal ОUT2. In the range r23, a large negative induced voltage is generated at the terminal ОUT1 and a positive induced voltage is generated at the terminal ОUT2.
When the needle jump rotation direction detection circuit 122 detects the appearance order of the induced voltages shown in FIG. 10A, it detects that the rotation direction of the rotor 202 is the normal rotation direction.
Further, in the case of the example shown in FIG. 10B, in the range r21, a positive induced voltage is generated at the terminal ОUT1, and a large negative induced voltage is generated at the terminal ОUT2. In the range r22, a large negative induced voltage is generated at the terminal ОUT1 and a positive induced voltage is generated at the terminal ОUT2.
When the needle jump rotation direction detection circuit 122 detects the appearance order of the induced voltages shown in FIG. 10B, it detects that the rotation direction of the rotor 202 is the reverse direction.

[Detection of needle jump rotation direction (Part 2: Detection based on appearance time width of induced voltage)]
The needle jump rotation direction detection circuit 122 (rotation direction detection unit) determines whether the rotation direction of the rotor 202 due to an external force is the forward rotation direction or the reverse rotation direction based on the appearance time width of the voltage induced in the coil 209. To detect.
For example, the needle jump rotation direction detection circuit 122 has a relatively long time width in the range r21 (that is, the range in which a large negative induced voltage is generated in the terminal ОUT1 and a positive induced voltage is generated in the terminal ОUT2). The rotation direction of the rotor 202 is calculated depending on whether the time is relatively short.
In the case of the example shown in FIG. 10A, the time width of the range r21 is relatively long. In this case, the needle jump rotation direction detection circuit 122 detects that the rotation direction of the rotor 202 is the normal rotation direction.
In the case of the example shown in FIG. 10B, the time width of the range r21 is relatively short. In this case, the needle jump rotation direction detection circuit 122 detects that the rotation direction of the rotor 202 is the reverse direction.

[Output of needle skip correction drive pulse when external force is applied]
The needle skip correction drive pulse generation circuit 117 (drive control unit) coiled the drive current Idrv that rotates the rotor 202 when the needle skip detection circuit 121 (external force detection unit) detects that an external force has been applied to the rotor 202. Supply to 209.
The case where the rotor 202 is rotated in the forward rotation direction by an external force will be described as an example. In the case of this example, the needle skip correction drive pulse generation circuit 117 supplies the drive current Idrv that rotates the rotor 202 in the forward rotation direction to the coil 209. That is, the needle skip correction drive pulse generation circuit 117 supplies the drive current Idrv that rotates the rotor 202 in a direction that coincides with the rotation direction of the rotor 202 due to an external force.

Further, in the needle skip correction drive pulse generation circuit 117, when the needle skip rotation direction detection circuit 122 detects the rotation direction of the rotor 202, the drive current Idrv rotates the rotor 202 in a direction corresponding to the detected rotation direction. May be supplied to the coil 209. That is, the needle skip correction drive pulse generation circuit 117 (drive control unit) has a needle jump rotation direction detection circuit 122 (rotation direction detection) among the drive current Idrv driving in the forward rotation direction and the drive current Idrv driving in the reverse direction. The drive current Idrv that rotates the rotor 202 in the direction corresponding to the rotation direction detected by the part) is supplied to the coil 209.
According to the needle skip correction drive pulse generation circuit 117 configured in this way, regardless of whether the rotation direction of the rotor 202 due to an external force is the forward rotation direction or the reverse rotation direction, the direction coincides with the rotation direction of the rotor 202. The drive current Idrv that rotates the rotor 202 can be supplied.

[Output of needle skipping suppression pulse when external force is applied]
In the above description, when needle skipping is detected, the drive current Idrv that rotates the rotor 202 in the same direction as the rotation direction of the rotor 202 due to an external force is supplied to the coil 209, but the present invention is not limited to this.
For example, the needle skip suppression pulse generation circuit 118 supplies the coil 209 with a braking current Ibrk that rotates the rotor 202 in a direction that does not match (that is, in the opposite direction) the rotation direction of the rotor 202 due to an external force when needle skip is detected. You may.

[Correction control after needle skipping due to external force]
Hereinafter, the needle skip correction drive pulse generation circuit 117 will be described as supplying a drive current Idrv that rotates the rotor 202 in a direction coincide with the rotation direction of the rotor 202 detected by the needle skip rotation direction detection circuit 122.
Further, in the following description, the case where the rotation direction of the rotor 202 detected by the needle jump rotation direction detection circuit 122 (that is, the rotation direction of the rotor 202 due to an external force) is the forward rotation direction is referred to as "forward rotation impact" and the reverse rotation direction. The case where is also described as "reverse impact".

FIG. 11 is a diagram showing an example of the behavior of the rotor 202 in the case of a normal rotation impact in the present embodiment. The needle skip correction drive pulse generation circuit 117 supplies a drive current Idrv in the normal rotation direction when the needle skip correction drive pulse generation circuit 117 detects a forward rotation impact (FIG. 11 (A)).
When the drive current Idrv in the forward rotation direction is supplied, the rotor 202 rotates in the forward rotation direction by one step due to the relative relationship between the rotational force due to the external force and the rotational force due to the drive current Idrv (FIG. 11 (B1)). ), Or the rotor 202 returns to the position before the supply of the drive current Idrv due to the reaction, and the rotational position of the rotor 202 does not change from the position before the supply of the drive current Idrv (FIG. 11 (B2)). Become.

FIG. 12 is a diagram showing an example of the behavior of the rotor 202 in the case of a reverse impact in the present embodiment. The needle skip correction drive pulse generation circuit 117 supplies a drive current Idrv in the reverse direction when the needle skip correction drive pulse generation circuit 117 detects a reverse impact (FIG. 12 (A)). When the rotor 202 is reversed, the needle skip correction drive pulse generation circuit 117 determines the drive current Idrv supplied to the coil 209 due to the relative positional relationship between the direction of the magnetic pole axis A of the rotor 202 and the horizontal magnetic pole. Change direction.
When the drive current Idrv in the reverse direction is supplied, does the rotor 202 rotate in the reverse direction by one step due to the relative relationship between the rotational force due to the external force and the rotational force due to the drive current Idrv (FIG. 12 (B1))? , The rotor 202 returns to the position before the supply of the drive current Idrv due to the reaction, and the rotational position of the rotor 202 does not change from the position before the supply of the drive current Idrv (FIG. 12 (B2)). ..

[Polarity detection after needle skipping occurs]
Returning to FIG. 11, it is detected whether the rotor 202 is rotated in the forward rotation direction by one step (FIG. 11 (B1)) or the rotation position of the rotor 202 is not changed by the drive current Idrv (FIG. 11 (B2)). Will be described. The needle jump rotation direction detection circuit 122 detects the direction of the magnetic pole axis A of the rotor 202 after the needle jump occurs.

In the needle jump rotation direction detection circuit 122, the rotation direction of the rotor 202 due to an external force is a forward rotation direction or a reverse rotation direction based on the relative positional relationship between the reference direction of the stator 201 and the rotation position of the magnetic pole of the rotor 202. Is detected.

Further, the polarity check pulse generation circuit 119 (inspection current supply unit) is a polarity check pulse (inspection current supply unit) that rotates the rotor 202 after the needle skip correction drive pulse generation circuit 117 (drive control unit) supplies the drive current Idrv to the coil 209. The inspection current Ichk) is supplied to the coil 209.

Specifically, the polarity detection circuit 120 (rotational position detection unit) generates an induced voltage generated in the coil 209 after the inspection current Ichk is supplied to the coil 209 by the polarity check pulse generation circuit 119 (inspection current supply unit). The rotation position of the magnetic pole of the rotor 202 is detected based on the pattern.
For example, in the case of a forward rotation impact, the polarity detection circuit 120 detects that the rotor 202 has rotated in the forward rotation direction by one step when the induced voltage shown in FIG. 11 (D1) is detected. Further, the polarity detection circuit 120 detects that the rotational position of the rotor 202 has not changed when the induced voltage shown in FIG. 11 (D2) is detected in the case of a normal rotation impact.
Further, in the case of a reverse impact, the polarity detection circuit 120 detects that the rotor 202 has rotated in the reverse direction by one step when the induced voltage shown in FIG. 12 (D1) is detected. Further, the polarity detection circuit 120 detects that the rotational position of the rotor 202 has not changed when the induced voltage shown in FIG. 12 (D2) is detected in the case of a reverse impact.

[Correction control of pointer position after needle skipping occurs]
The rotation correction circuit 116 corrects the rotation position of the pointer 155 after the occurrence of needle skipping by controlling the state of the drive current Idrv supplied to the coil 209 according to the occurrence status of needle skipping. An example of the rotation position correction method of the pointer 155 by the rotation correction circuit 116 is shown below.

(1) The rotation correction circuit 116 supplies the drive current Idrv in the reverse direction to the coil 209 to move the rotation position of the pointer 155 in the reverse direction.
(2) The rotation correction circuit 116 stops the process of supplying the drive current Idrv in the forward rotation direction to the coil 209, and holds the rotation position of the pointer 155.
(3) The rotation correction circuit 116 does not stop the process of supplying the drive current Idrv in the forward rotation direction to the coil 209. That is, the rotation correction circuit 116 supplies the drive current Idrv under the same control as in the case where needle skipping does not occur.

[Correction control after needle skipping occurs (Part 1: When one step of needle skipping occurs in the forward rotation direction)]
As shown in FIG. 11 (C1), when a needle jump of one step occurs in the forward rotation direction, a step of advance occurs at the position of the pointer 155. In this case, the rotation correction circuit 116 corrects the rotation position of the pointer 155 by any of the correction methods (1) to (3) described above.
In addition, when the needle jump of one step occurs in the forward rotation direction, even if the drive current Idrv on the premise that the needle jump does not occur is supplied to the coil 209, the magnetic flux axis A of the rotor 202 Since the direction of the magnetic field due to the magnetic flux of the coil 209 is substantially the same, the rotor 202 does not rotate. Therefore, even if the rotation correction circuit 116 supplies the drive current Idrv without stopping the process of supplying the drive current Idrv to the coil 209, the rotor 202 does not rotate. As a result, the needle skipping of the pointer 155 is eliminated.

[Correction control after needle jump (Part 2: When one step of needle jump occurs in the reverse direction)]
As shown in FIG. 12 (C1), when a needle jump of one step occurs in the reverse direction, a delay of one step occurs at the position of the pointer 155. In this case, the rotation correction circuit 116 supplies the drive current Idrv in the forward rotation direction to correct the rotation position of the pointer 155.

[Correction control after needle skipping occurs (Part 3: When needle skipping does not occur)]
As shown in FIG. 11 (C2) or FIG. 12 (C2), when the rotation position of the rotor 202 returns to the position before the supply of the drive current Idrv, and as a result, needle skipping does not occur, the position of the pointer 155. Has not changed due to external force. In this case, the rotation correction circuit 116 corrects the rotation position of the pointer 155 by the correction method (3) described above.

As shown in FIG. 12 (B1) or FIG. 12 (B2), when a needle jump in the reverse direction is detected, the rotor is rotated in the direction opposite to the rotation direction of the rotor 202 due to an external force instead of the output of the polarity check pulse. A braking current Ibrk that rotates 202 may be supplied to the coil 209. When the braking current Ibrk is supplied to the coil 209 in FIG. 12 (B1), the rotor 202 rotates and moves to return to the state of FIG. 12 (A). When the braking current Ibrk is supplied to the coil 209 in FIG. 12 (B2), the rotor 202 does not rotate because FIG. 12 (B2) is originally in the same state as in FIG. 12 (A). That is, whether the braking current Ibrk is supplied to the coil 209 in the state of FIG. 12 (B1) or the braking current Ibrk is supplied to the coil 209 in the state of FIG. 12 (B2), the result is the same (FIG. 12). 12 (A)). The supply of such braking current Ibrk also serves as correction control.

[Example of operation of stepping motor control device 100]
FIG. 13 is a diagram showing an example of the operation of the stepping motor control device 100 of the present embodiment.
(Step S10) The needle jump detection circuit 121 detects that an external force is applied to the rotor 202 (for example, an impact due to dropping).
(Step S20) If the needle skip detection circuit 121 does not detect that an external force has been applied to the rotor 202 (step S20; NO), the control circuit 103 proceeds to step S30. When the control circuit 103 detects that an external force has been applied to the rotor 202 (step S20; YES), the needle skip detection circuit 121 proceeds to step S40.
(Step S30) The stepping motor control device 100 performs normal control when there is no impact.

(Step S40) The needle jump rotation direction detection circuit 122 detects the needle jump rotation direction (impact direction) due to an external force.

[In the case of forward impact]
FIG. 14 is a diagram showing an example of a state in which an external force in the forward rotation direction is applied to the rotor 202 of the present embodiment. FIG. 15 is a diagram showing an example of a waveform when an external force in the forward rotation direction is applied to the rotor 202 of the present embodiment. When an external force is applied to the rotor 202 to rotate in the forward rotation direction (trajectory r10 in FIG. 14), an induced voltage indicating a forward rotation impact is generated in the first terminal OUT1 (voltage V10 in FIG. 15).

(Step S50) When the control circuit 103 detects that the needle jump rotation direction detection circuit 122 is in the forward rotation direction (that is, the forward rotation impact), the process is performed (step S50; YES). Proceed to step S60. When the control circuit 103 detects that the needle jump rotation direction detection circuit 122 detects that the needle jump rotation direction is the reverse direction (that is, reverse impact) (step S50; NO), the process proceeds to step S110.

(Step S60) The needle skip correction drive pulse generation circuit 117 supplies the drive current Idrv in the forward rotation direction to the coil 209 (drive current Idrv in FIG. 15).
(Step S70) The polarity check pulse generation circuit 119 supplies a polarity check pulse (inspection current Ichk in FIG. 15). The polarity detection circuit 120 detects the rotational position of the magnetic pole of the rotor 202 based on the generation pattern of the induced voltage generated in the coil 209.
(Step S80) When the polarity detection circuit 120 detects that the polarity detection circuit 120 has made a normal rotation in one step (step S80; YES), the process proceeds to step S100. When the control circuit 103 detects that the polarity detection circuit 120 has not rotated in the normal direction in one step (that is, the rotation position of the rotor 202 has not changed) (step S80; NO), the process is performed in step S90. Proceed to.
(Step S90) The rotation correction circuit 116 controls when the rotation position of the rotor 202 has not changed.
(Step S100) The rotation correction circuit 116 controls the normal rotation in one step.

[In case of reverse impact]
FIG. 16 is a diagram showing an example of a state in which an external force in the reverse direction is applied to the rotor 202 of the present embodiment. FIG. 17 is a diagram showing an example of a waveform when an external force in the reverse direction is applied to the rotor 202 of the present embodiment. When an external force is applied to the rotor 202 to rotate in the reverse direction (trajectory r11 in FIG. 16), an induced voltage indicating a reverse impact is generated in the second terminal OUT2 (voltage V11 in FIG. 17).
(Step S110) The needle skip correction drive pulse generation circuit 117 supplies the drive current Idrv in the reverse direction to the coil 209 (drive current Idrv in FIG. 17).
(Step S120) The polarity check pulse generation circuit 119 supplies the polarity check pulse (inspection current Ichk in FIG. 17). The polarity detection circuit 120 detects the rotational position of the magnetic pole of the rotor 202 based on the generation pattern of the induced voltage generated in the coil 209.
(Step S130) When the polarity detection circuit 120 detects that the polarity detection circuit 120 has reversed one step (step S130; YES), the process proceeds to step S140. When the control circuit 103 detects that the polarity detection circuit 120 has not reversed one step (that is, the rotation position of the rotor 202 has not changed) (step S130; NO), the process is performed in the step described above. Proceed to S90.
(Step S140) The rotation correction circuit 116 controls when one step is reversed.

The stepping motor control device 100 according to the embodiment has been described above. When an external force attempts to rotate the rotor 202, the stepping motor control device 100 sets the rotor 202 in the direction in which the rotor 202 is rotated by the external force (for example, in the forward rotation direction if it is a forward rotation impact, in the reverse rotation direction if it is a reverse rotation impact). Drives the rotor 202. That is, the stepping motor control device 100 applies a magnetic field due to the drive current to the rotor 202 when an external force tries to rotate the rotor 202. With this configuration, the stepping motor control device 100 can stabilize the rotation of the rotor 202 as compared with the case where the rotor 202 is not driven when an external force is applied to the rotor 202. Therefore, according to the stepping motor control device 100 of the present embodiment, it is possible to improve the accuracy of time correction when an external force is applied.

Here, according to the prior art, when the rotor is rotated by an external force, the direction is opposite to the direction in which the rotor is rotated by the external force (for example, a reverse rotation direction for a forward rotation impact and a normal rotation direction for a reverse rotation impact). There is something that drives the rotor. When the rotor is driven (braked) in the direction opposite to the direction in which the rotor is rotated by an external force, for example, when the mass of the pointer rotated by the rotor is relatively large, the braking force due to the drive in the opposite direction is insufficient. There is a problem that it is difficult to prevent the rotor from rotating due to an external force.

Further, according to the above-mentioned conventional technology, when the rotor rotates one step without being able to completely brake the rotation of the rotor due to an external force, the direction of the magnetic poles of the rotor and the magnetic flux due to the drive current at the next drive timing. There may be cases where the rotor cannot be rotated due to inconsistency with the direction of. For example, when the rotor is rotated by one step in the reverse direction due to an external force, the rotor does not rotate in the forward direction at the next drive timing, and there is a problem that a deviation of two steps occurs.

Since the stepping motor control device 100 of the present embodiment gives rotation correction to the rotor 202 based on the rotation direction of the rotor 202 and the rotation position (direction of the magnetic pole axis A) when the rotation is stopped, the step deviation is suppressed. can do.
That is, the clock 1 of the present embodiment accurately grasps the direction in which the rotor 202 has rotated due to an impact and the number of steps rotated in that direction, and when the rotor 202 has rotated in the forward rotation direction due to an impact, or when the impact In any case where the watch has rotated in the reverse direction, it is possible to perform appropriate time correction with high accuracy.

All or part of the functions of the clock 1 described above may be recorded as a program on a computer-readable recording medium, and this program may be executed by the computer system. The computer system shall include hardware such as an OS and peripheral devices. Computer-readable recording media include, for example, flexible disks, magneto-optical disks, portable media such as ROM (Read Only Memory) and CD-ROM, storage devices such as hard disks built into computer systems, and the Internet. It is a volatile memory (Random Access Memory: RAM) provided in a server or the like on a network. The volatile memory is an example of a recording medium that holds a program for a certain period of time.

Further, the above-mentioned program may be transmitted to another computer system by a transmission medium such as a network such as the Internet or a communication line such as a telephone line.

Further, the above-mentioned program may be a program that realizes all or a part of the above-mentioned functions. The program that realizes a part of the above-mentioned functions may be a program that can realize the above-mentioned functions in combination with a program recorded in advance in the computer system, a so-called difference program.

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 ... Clock, 100 ... Stepping motor control device, 101 ... Oscillation circuit, 102 ... Frequency division circuit, 103 ... Control circuit, 104 ... Main drive pulse generation circuit, 105 ... Correction drive pulse generation circuit, 106 ... Motor drive circuit, 113 ... rotation detection circuit, 116 ... rotation correction circuit, 117 ... needle skip correction drive pulse generation circuit, 118 ... needle skip suppression pulse generation circuit, 119 ... polarity check pulse generation circuit, 120 ... polarity detection circuit, 121 ... needle skip detection circuit

Claims (8)

A rotor that rotates the pointer in the forward rotation direction that rotates the pointer clockwise and a rotor that rotates the pointer in the reverse rotation direction that is the opposite direction to the forward rotation direction, a coil that generates a magnetic flux by passing a drive current, and the coil. A stepping motor control device for controlling a stepping motor including a stator that applies a generated magnetic flux to the rotor.
An external force detection unit that detects that an external force other than the force due to the magnetic flux is applied to the rotor based on the state of the voltage induced in the coil.
When the external force detecting unit detects that the external force is applied to the rotor, the drive control unit that supplies the drive current for rotating the rotor to the coil.
A stepper motor control device. A rotation direction detection unit for detecting whether the rotation direction of the rotor due to the external force is the forward rotation direction or the reverse rotation direction based on the state of the voltage induced in the coil is further provided.
The drive control unit
Of the drive current driven in the forward rotation direction and the drive current driven in the reverse rotation direction, a drive current for rotating the rotor in a direction corresponding to the rotation direction detected by the rotation direction detection unit is supplied to the coil. The stepping motor control device according to claim 1. The rotation direction detection unit
The second aspect of claim 2, wherein the rotation direction of the rotor due to the external force is detected to be the forward rotation direction or the reverse rotation direction based on the appearance order of the voltages induced at any of both ends of the coil. Stepping motor control device. The rotation direction detection unit
The second or third aspect of the present invention, which detects whether the rotation direction of the rotor due to the external force is the forward rotation direction or the reverse rotation direction based on the appearance time width of the voltage induced in the coil. Stepping motor control device. The rotor is magnetized to at least two poles, an N pole and an S pole.
Further provided with a rotation position detecting unit that detects the direction of the magnetic pole of the rotor rotated by the external force based on the relative positional relationship between the reference direction of the stator and the direction of the magnetic pole of the rotor.
The drive control unit
The stepping motor control device according to any one of claims 1 to 4, which controls the state of the drive current supplied to the coil based on the direction of the magnetic poles of the rotor detected by the rotation position detection unit. .. After the drive control unit supplies the drive current to the coil, the drive control unit further includes an inspection current supply unit that supplies an inspection current for rotating the rotor to the coil.
The rotation position detecting unit includes a claim that detects the rotation position of the magnetic pole of the rotor based on the state of the voltage induced in the coil after the inspection current is supplied to the coil by the inspection current supply unit. Item 5. The stepping motor control device according to Item 5. The stepping motor control device according to any one of claims 1 to 6.
With the stepping motor
A watch with the pointer. A rotor that rotates the pointer in the forward rotation direction that rotates the pointer clockwise and a rotor that rotates the pointer in the reverse rotation direction that is the opposite direction to the forward rotation direction, a coil that generates magnetic flux by passing a drive current, and the coil. A method for controlling a stepping motor including a stator that applies a generated magnetic flux to the rotor.
An external force detection step for detecting that an external force other than the force due to the magnetic flux is applied to the rotor based on the state of the voltage induced in the coil.
A drive control step of supplying a drive current for rotating the rotor to the coil when it is detected in the external force detection step that the external force is applied to the rotor.
Stepping motor control method having.

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