JP2022099498A - Motor control circuit for watch, movement, electronic watch, and method for controlling electronic watch - Google Patents

Abstract

To provide a motor control circuit for a watch that can execute fast-forward drive of a motor even during the detection of an external magnetic field, a movement, an electronic watch, and a method for controlling an electronic watch.SOLUTION: A motor control circuit for a watch comprises: a driver that is controlled to an on-state for supplying a driving current to a coil of a motor and an off-state for not supplying the driving current; a current detection unit that detects a value of current flowing in the coil; a target current value setting unit that sets a target current value; a driver control unit that compares the current value detected by the current detection unit with the target current value, and controls the driver to the on-state or the off-state according to a result of the comparison; a polarity switching unit that alternately switches a polarity of the driving current to a first polarity and a second polarity; and an external magnetic field detection unit that detects an external magnetic field. When the external magnetic filed detection unit detects the external magnetic field, the target current value setting unit changes the target current value.SELECTED DRAWING: Figure 4

Description

The present invention relates to a motor control circuit for a timepiece, a movement, an electronic timepiece, and a control method for the electronic timepiece.

Patent Document 1 includes a control unit that controls a driver to an on state or an off state according to a current value flowing through a motor coil, and an external magnetic field detection unit that detects an external magnetic field based on the on state or the off state. An electronic clock comprising the above is disclosed. According to Patent Document 1, when an external magnetic field is detected, by stopping the driving of the motor, the motor is fast-forwarded and driven while being affected by the external magnetic field, causing problems such as the needle position being out of order. It is disclosed to prevent.

Japanese Unexamined Patent Publication No. 2020-159734

Patent Document 1 has a problem that if an external magnetic field is detected during the fast-forward driving of the motor, the driving of the motor is stopped, so that the fast-forwarding drive of the motor cannot be executed during the detection of the external magnetic field.

The clock motor control circuit of the present disclosure is a clock motor control circuit that controls a motor having a coil and a rotor, and is in an on state in which a drive current is supplied to the coil and an off state in which the drive current is not supplied. A controlled driver, a current detection unit that detects the current value flowing through the coil, a target current value setting unit that sets a target current value, and the current value and the target current value detected by the current detection unit. By comparison, the driver control unit that controls the driver to the on state or the off state according to the result of the comparison, and the polarity switching that alternately switches the polarity of the drive current between the first polarity and the second polarity. The target current value setting unit includes a unit and an external magnetic field detection unit that detects an external magnetic field, and is characterized in that the target current value setting unit changes the target current value when the external magnetic field is detected by the external magnetic field detection unit. And.

The movement of the present disclosure is characterized by comprising a motor having a coil and a rotor, and the above-mentioned motor control circuit for a timepiece.

The electronic clock of the present disclosure is characterized by including the above-mentioned movement.

The control method of the electronic clock of the present disclosure is a control method of an electronic clock including a motor having a coil and a rotor, and is an on state in which a drive current is supplied to the coil and an off state in which the drive current is not supplied to the coil. The rotor is rotated based on the result of comparison between the current value flowing through the coil and the target current value, and when the rotor is rotated by a predetermined amount, the polarity of the drive current is changed to the first polarity and the second polarity. It is characterized in that the target current value is changed when an external magnetic field is detected by alternately switching to the polarity.

The front view which shows the electronic clock of 1st Embodiment. The circuit diagram which shows the circuit structure of the electronic timepiece of 1st Embodiment. The figure which shows the structure of the 1st motor of the electronic timepiece of 1st Embodiment. The block diagram which shows the structure of the IC of the electronic timepiece of 1st Embodiment. The circuit diagram which shows the structure of the 1st motor control circuit of 1st Embodiment. The waveform diagram which shows the drive waveform in the steady state of the 1st motor of 1st Embodiment. The waveform diagram which shows the drive waveform at the time of being influenced by the external magnetic field of the 1st motor of 1st Embodiment. The figure explaining the influence of the external magnetic field in the 1st motor of 1st Embodiment. The figure explaining the influence of the external magnetic field in the 1st motor of 1st Embodiment. The flowchart explaining the drive control processing of the 1st motor of 1st Embodiment. The flowchart explaining the drive control processing of the 1st polarity of 1st Embodiment. The flowchart explaining the drive control processing of the 2nd polarity of 1st Embodiment. The flowchart explaining the drive control processing of the 1st polarity of 2nd Embodiment. The flowchart explaining the drive control processing of the 2nd polarity of 2nd Embodiment.

[First Embodiment]
Hereinafter, the electronic clock 1 of the first embodiment will be described with reference to the drawings.
FIG. 1 is a front view showing an electronic clock 1.
The electronic clock 1 is a chronograph clock having a stopwatch function and the like.
As shown in FIG. 1, the electronic clock 1 includes a disk-shaped dial 2, a second hand 3, a minute hand 4, an hour hand 5, a crown 6, an A button 7, and a B button 8.

[Circuit configuration of electronic clock]
FIG. 2 is a diagram showing a circuit configuration of the electronic clock 1.
As shown in FIG. 2, the electronic clock 1 includes a movement 10 for driving a second hand 3, a minute hand 4, and an hour hand 5.

The movement 10 includes a crystal oscillator 11 as a signal source, a battery 12 as a power source, switches SW1 to SW3, a first motor 13, a second motor 14, and an IC 20 for a clock. To.
The switch SW1 is turned on and off in conjunction with the withdrawal operation of the crown 6 shown in FIG. The switch SW2 is turned on and off in conjunction with the operation of the A button 7. The switch SW3 is turned on and off in conjunction with the operation of the B button 8.
The first motor 13 is a stepping motor that drives the second hand 3, and the second motor 14 is a stepping motor that drives the minute hand 4 and the hour hand 5. The first motor 13 and the second motor 14 are examples of motors. IC is an abbreviation for Integrated Circuit.

The IC 20 includes connection terminals OSC1 and OSC2 to which the crystal oscillator 11 is connected, input / output terminals G1 to G3 to which switches SW1 to SW3 are connected, power supply terminals VDD and VSS to which the battery 12 is connected, and a first motor. It includes output terminals O1 and O2 connected to 13 and output terminals O3 and O4 connected to the second motor 14.
In this embodiment, the positive electrode of the battery 12 is connected to the power supply terminal VDD on the high potential side, the negative electrode is connected to the power supply terminal VSS on the low potential side, and the power supply terminal VSS on the low potential side is used as the reference potential. It is set.

The battery 12 is composed of a primary battery or a secondary battery. In the case of a secondary battery, it is charged by a solar cell or the like (not shown).

FIG. 3 is a diagram showing the configuration of the first motor 13. Although the description is omitted, the second motor 14 has the same configuration as the first motor 13.
As shown in FIG. 3, the first motor 13 includes a stator 131, a coil 130, and a rotor 133. Both ends of the coil 130 are conducted to the output terminals O1 and O2 of the IC 20. Further, the rotor 133 is a magnet magnetized in two poles in the radial direction. Therefore, the first motor 13 is a two-pole single-phase stepping motor used for an electronic clock, and is driven by a drive current supplied from the output terminals O1 and O2 of the IC 20.

For example, when a drive current is passed from the output terminal O1 to the output terminal O2 in the coil 130, a counterclockwise magnetic field is generated in FIG. By polarizing the stator 131 with the magnetic field, it repels the rotor 133 and rotates the rotor 133 by 180 °, which is a unit amount. When the rotor 133 has completely rotated 180 °, a drive current is passed from the output terminal O2 to the output terminal O1. Then, a clockwise magnetic field is generated in FIG. The magnetic field causes the stator 131 to be polarized in the opposite direction to the rotor 133, causing the stator 131 to repel the rotor 133 and further rotate the rotor 133 by 180 °. The rotor 133 continues to rotate by repeating this operation. In this way, switching the output terminals O1 and O2 for supplying the drive current each time the rotor 133 rotates by a unit amount to switch the direction in which the drive current flows corresponds to switching the polarity of the drive current. The IC 20 of the present embodiment alternately and repeatedly switches between two polarities, a first polarity in which a drive current flows from the output terminal O1 to the output terminal O2 and a second polarity in which a drive current flows from the output terminal O2 to the output terminal O1. , Rotor 133 is rotated by a desired rotation amount. In the present specification, the posture of the rotor 133 that can be represented by an angle of 0 to 360 ° is referred to as a "rotation angle", and the cumulative rotation angle when the unit amount of rotation is repeated a plurality of times is the "rotation amount". ".
Similarly, the second motor 14 is driven by the drive current supplied to the output terminals O3 and O4 of the IC 20.

[IC circuit configuration]
FIG. 4 is a configuration diagram showing the configuration of the IC 20.
As shown in FIG. 4, the IC 20 includes an oscillation circuit 21, a frequency dividing circuit 22, a CPU 23 for controlling the electronic clock 1, a ROM 24, an input circuit 26, a BUS 27, a first motor control circuit 30A, and the like. It includes a second motor control circuit 30B. The first motor control circuit 30A and the second motor control circuit 30B are examples of the motor control circuit. Further, CPU is an abbreviation for Central Processing Unit, and ROM is an abbreviation for Read Only Memory.

The oscillation circuit 21 oscillates the crystal oscillator 11 which is the reference signal source shown in FIG. 2 at high frequency, and outputs an oscillation signal of a predetermined frequency (32768 Hz) generated by this high frequency oscillation to the frequency dividing circuit 22.
The frequency dividing circuit 22 divides the output of the oscillation circuit 21 and supplies a timing signal to the CPU 23.
The ROM 24 stores various programs executed by the CPU 23. In the present embodiment, the ROM 24 stores a program for realizing a basic clock function, a stopwatch function, a time difference correction function, and the like.
The CPU 23 executes the program stored in the ROM 24 and realizes each of the above functions.

The input circuit 26 outputs the states of the input / output terminals G1 to G3 to the BUS 27. The BUS 27 is used for data transfer between the CPU 23, the input circuit 26, the first motor control circuit 30A, the second motor control circuit 30B, and the like.
The first motor control circuit 30A and the second motor control circuit 30B supply a predetermined drive current to the coils 130 of the first motor 13 and the second motor 14 by a command input from the CPU 23 through the BUS 27.

[Motor control circuit configuration]
The first motor control circuit 30A controls the first motor 13 so that the second hand 3 can be moved in the forward and reverse directions, that is, in both clockwise and counterclockwise directions. Therefore, the first motor control circuit 30A may be any as long as it can drive and control the first motor 13 in the forward and reverse directions.

The second motor control circuit 30B controls the second motor 14 so that the minute hand 4 and the hour hand 5 can be moved in both forward and reverse directions.

FIG. 5 is a circuit diagram showing the configuration of the first motor control circuit 30A. The configuration of the second motor control circuit 30B is the same as that of the first motor control circuit 30A.
The first motor control circuit 30A includes a decoder 31, a driver 50, and a current detection circuit 60.
The decoder 31 outputs the gate signals P1, P2, N1, N2, N3, N4 as control signals to the driver 50 from the CPU 23 via the BUS 27. Therefore, the CPU 23, the BUS 27, and the decoder 31 are driver control units that control the driver 50.

The driver 50 supplies a drive current to the coil 130 of the first motor 13. The driver 50 includes two Pch transistors 52, 53, four Nch transistors 54, 55, 56, 57, and two detection resistors 58, 59. Each of the transistors 52 to 57 is controlled by a control signal output from the decoder 31, and supplies currents I in both forward and reverse directions to the coil 130 of the first motor 13.

The current detection circuit 60 includes a first reference voltage generation circuit 62, a second reference voltage generation circuit 63, a comparator 641,642,651,652, and composite gates 68 and 69. The composite gate 68 is one element having the same function as that of a combination of the AND circuit 661 and 662 and the OR circuit 680. The composite gate 69 is one element having the same function as that of the combination of the AND circuit 671, 672 and the OR circuit 690.

The comparators 641 and 642 compare the voltage generated across the coil 130 with the voltage of the first reference voltage generating circuit 62, respectively.
Since the drive polarity signal PL output from the decoder 31 is inverted and input to the AND circuit 661 and the drive polarity signal PL is input to the AND circuit 662 as it is, the comparator 641 selected by the drive polarity signal PL One output of 642 is output as the detection signal DT1.
The comparators 651 and 652 compare the voltage generated across the coil 130 with the voltage of the second reference voltage generation circuit 63, respectively.
Since the drive polarity signal PL is inverting input to the AND circuit 671 and the drive polarity signal PL is input to the AND circuit 672 as it is, one output of the comparators 651 and 652 selected by the drive polarity signal PL is detected. It is output as a signal DT2.

The first reference voltage generation circuit 62 generates a voltage corresponding to the lower limit target current value Imin. Specifically, the first reference voltage generation circuit 62 is set to output a potential corresponding to the voltage generated at both ends of the coil 130 when the current I flowing through the coil 130 is the lower limit target current value Imin. ..
Therefore, when the current I flowing through the coil 130 is equal to or greater than the lower limit target current value Imin, the voltage generated across the coil 130 is equal to or greater than the output voltage of the first reference voltage generating circuit 62, so that the detection signal DT1 is H level. Become. On the other hand, when the current I is lower than the lower limit target current value Imin, the detection signal DT1 becomes the L level. Therefore, the first reference voltage generation circuit 62, the comparator 641, 642, and the composite gate 68 of the current detection circuit 60 are configured to be able to detect that the current I flowing through the coil 130 is smaller than the lower limit target current value Imin.

The second reference voltage generation circuit 63 generates a voltage corresponding to the upper limit target current value Imax. Therefore, the detection signal DT2 of the current detection circuit 60 becomes H level when the current I flowing through the coil 130 exceeds the upper limit target current value Imax, and becomes L level when it is equal to or less than the upper limit target current value Imax. Therefore, the second reference voltage generation circuit 63, the comparator 651, 652, and the composite gate 69 of the current detection circuit 60 are configured to be able to detect that the current I flowing through the coil 130 exceeds the upper limit target current value Imax. There is.
Therefore, the current detection circuit 60 functions as a current detection unit that detects the current value flowing through the coil 130.

Next, when the A button 7 is pressed for 3 seconds or more and the stopwatch mode is selected, the control method for driving the second hand 3 to the position of 0 seconds in forward rotation and fast forward, that is, the second hand 3 is moved at high speed. The control method at the time of making is described.

[Operation of motor control circuit]
The CPU 23 of the IC 20 calculates the target number of steps N when the stopwatch mode is set.
In the present embodiment, one step is to rotate the rotor 133 by 180 °, which is a unit amount, and the second hand 3 is rotated by 360 ° / 60 = 6 ° in one step. The CPU 23 calculates the number of steps required to rotate the second hand 3 from the current position in the forward rotation direction, that is, clockwise to the 0 second position as the target number of steps N. In this case, the amount of rotation of the rotor 133 required to rotate the second hand 3 to the position of 0 seconds, that is, the desired amount of rotation is N × 180 °.

FIG. 6 is a waveform diagram showing the drive waveform of the first motor 13, in which the horizontal axis represents time and the vertical axis represents the magnitude of the signal.

The first motor control circuit 30A operates so that the current I flowing through the coil 130 becomes a substantially constant current between the upper limit target current value Imax and the lower limit target current value Imin. Specifically, when the current I detected by the current detection circuit 60 is smaller than the lower limit target current value Imin, the CPU 23, which is a driver control unit, has gate signals P1 and P2 so that a drive current flows through the coil 130. , N1, N2, N3, N4 are controlled, and when the current I detected by the current detection circuit 60 is larger than the upper limit target current value Imax, the gate signals P1 and P2 are prevented from flowing through the coil 130. , N1, N2, N3, N4 are controlled. Hereinafter, the state in which the driver 50 supplies the drive current to the coil 130 of the first motor 13 is referred to as an "on state", and the state in which the driver 50 stops supplying the drive current is also referred to as an "off state". .. Further, the time from when the supply of the drive current is started until the current I exceeds the upper limit target current value Imax and the supply of the drive current is stopped, that is, the duration of the on state is also called "on time", and the drive current of the drive current The time from when the supply is stopped until the current I falls below the lower limit target current value Imin and the supply of the drive current is started, that is, the duration of the off state is also referred to as "off time".

In such a driving method, the rotation angle of the rotor 133 has a correlation with the on time and the off time. Therefore, when the on time and the off time correspond to a predetermined condition, the polarity can be switched at the optimum switching timing by switching between the first polarity and the second polarity. Specifically, since the off time becomes long at the timing when the rotation of the unit amount of the rotor 133, that is, the rotation of 180 ° ends, the CPU 23, which is the driver control unit, determines that the rotor exceeds a predetermined threshold value. It is determined that the 133 has rotated by a unit amount, and the polarity is switched.

In the first polarity and the second polarity, the polarity is switched to start driving the first motor 13, and the time until the rotor 133 is determined to have rotated 180 ° and the polarity is switched, that is, the first in each polarity. The time for driving one motor 13 is defined as the drive pulse length. In FIG. 6, the drive pulse length of the first polarity is T01, and the drive pulse length of the second polarity is T02. The drive pulse lengths T01 and T02 are the time required for the rotor 133 to rotate by 180 °, which is a unit amount, and are also referred to as a unit amount rotation time. The first drive, which is the drive from the completely stationary state of the rotor 133, has a longer unit amount rotation time than the subsequent drive, but the drive after the rotor 133 starts to rotate has a unit amount rotation time. There is no big difference.

[Effect of magnetic field]
Next, the influence of the external magnetic field on the first motor 13 will be described with reference to FIGS. 7 to 9. Since the electronic timepiece 1 is worn by a user and used in various environments, it may be affected by an unintended external magnetic field. In this case, the hand movement may be faster or slower, or even stop. This is because the on-time for flowing the drive current and the off-time for stopping the drive current fluctuate due to the influence of the external magnetic field during hand movement control, and the rotation angle of the rotor cannot be estimated normally.
In the present embodiment, the current flowing through the coil 130 from the output terminal O1 to the output terminal O2 is a current in the positive direction. Further, in the present embodiment, the drive current supplied to the coil 130 is switched between the first polarity and the second polarity, and in the case of the first polarity, the current in the positive direction flows through the coil 130.

FIG. 7 is a waveform diagram showing a drive waveform when an external magnetic field is applied to the first motor 13, where the horizontal axis shows time and the vertical axis shows the magnitude of a signal.
FIG. 8 is a diagram showing the first motor 13, showing a state in which the driver 50 is controlled to be in the ON state by the drive current of the first polarity. In the present embodiment, when a drive current is passed from the output terminal O1 to the output terminal O2 with respect to the coil 130, a counterclockwise magnetic field H1 is generated in the stator 131 as shown by the dotted line in FIG.
FIG. 9 is a diagram showing the first motor 13, showing a state in which the driver 50 is controlled to be in the ON state by the drive current of the second polarity. In the present embodiment, when a drive current is passed from the output terminal O2 to the output terminal O1 with respect to the coil 130, a clockwise magnetic field H2 is generated in the stator 131 as shown by the dotted line in FIG.

As shown in FIGS. 8 and 9, when an unintended external magnetic field H3 is applied to the first motor 13, the external magnetic field H3 is added to the magnetic field H1 or the magnetic field H2 by the coil 130. This effect depends on the polarity of the drive and is exactly the opposite for a two-pole step motor. Therefore, the movement of the rotor 133 becomes unbalanced depending on the polarity of the drive current, and the rising and falling times of the current change. Therefore, the drive waveform when driven with a constant current differs depending on the polarity.

For example, as shown in FIG. 8, when the external magnetic field H3 is applied in the direction opposite to the magnetic field H1 by the coil 130, the force applied to the rotor 133 by the magnetic field becomes small. Therefore, the rotor 133 becomes difficult to rotate, and the drive current also becomes difficult to rise. As shown on the first electrode side in FIG. 7, the drive pulse length T1 of the first motor 13 is the steady drive in FIG. It is longer than the drive pulse length T01 on the first electrode side. That is, the external magnetic field H3 inhibits the rotation of the rotor 133 at the first polarity.
On the other hand, as shown in FIG. 9, when the external magnetic field H3 is applied in the same direction as the magnetic field H2 by the coil 130, the force applied to the rotor 133 by the magnetic field also increases. Therefore, the rotor 133 is easy to rotate, the drive current is easy to rise, and as shown on the second electrode side of FIG. 7, the drive pulse length T2 of the first motor 13 is the second during steady drive in FIG. It is shorter than the drive pulse length T02 on the electrode side of 2. That is, the external magnetic field H3 contributes to the rotation of the rotor 133 at the second polarity.
That is, comparing the drive pulse waveform diagram in the case of steady drive shown in FIG. 6 and the drive pulse waveform diagram in the case of applying an external magnetic field shown in FIG. 7, the first polarity is obtained during steady drive. The drive pulse lengths T01 and T02 of the first motor 13 are almost the same as those of the second polarity. On the other hand, when an external magnetic field is applied, the drive pulse lengths T1 and T2 of the first motor 13 differ greatly between the first polarity and the second polarity. This is because, depending on the direction of the external magnetic field H3 and the direction of the magnetic field of the coil 130 itself, the drive current may be synergistically easy to flow, or may cancel each other out to make it difficult for the current to flow.
In the present embodiment, as described above, the difference between the drive waveforms in the first polarity and the second polarity, which occurs when an external magnetic field is present, specifically, the absolute value of the difference between the drive pulse lengths T1 and T2 is used. It can be detected and the presence or absence of an external magnetic field can be detected.

Hereinafter, the drive control process of the first motor 13 by the CPU 23 will be described.
FIG. 10 is a flowchart illustrating the operation of the CPU 23 when the stopwatch mode is set.
When the stopwatch mode is set, the CPU 23 executes step S1 and sets an initial value of the target current value. Specifically, the CPU 23 has an upper limit target current value Imax_O1 and a lower limit target current value Imin_O1 during operation at the first polarity, and an upper limit target current value Imax_O2 and a lower limit target current value Imin_O2 during operation at the second polarity. Set the initial value of and. In step S1, the CPU 23 sets the upper limit target current values Imax_O1 and Imax_O2 to the same values, and sets the lower limit target current values Imin_O1 and Imin_O2 to values lower than the upper limit target current values Imax_O1 and Imax_O2 by a fixed value ΔI. .. The CPU 23 sets a reference voltage in the first reference voltage generation circuit 62 and the second reference voltage generation circuit 63 via the BUS 27 and the decoder 31 based on these upper limit target current values and lower limit target current values.

Next, the CPU 23 executes step S2 and acquires the target number of steps N for moving the second hand 3 from the current position to the 0 second position. Further, the CPU 23 executes step S3 and sets the count value n for counting the number of executed steps to 0.
Next, the CPU 23 executes step S4 and determines whether or not the current polarity is the first polarity. Then, the CPU 23 executes the first polarity drive control in step S10 when it is determined to be YES in step S4, and executes the second polarity drive control in step S30 when it is determined to be NO in step S4. .. Each drive control of S10 and S30 will be described later.
When the CPU 23 executes each drive control in steps S10 and S30 to move the first motor 13 one step, the CPU 23 adds 1 to the count value n in step S5.
Next, the CPU 23 determines in step S6 whether or not the count value n is equal to the target number of steps N. If the CPU 23 determines YES in step S6, the second hand 3 has returned to the 0 second position, so that the CPU 23 ends the drive. If the CPU 23 determines NO in step S6, the CPU 23 returns to step S4 and repeats the above process.

[First polarity drive control]
When the CPU 23 executes the first polarity drive control in step S10, the CPU 23 executes step S11 and turns on the driver 50 as shown in FIG. At this time, in order to turn on the driver 50 with the first polarity, the CPU 23 outputs gate signals P1, P2, N1, N2, N3, N4 via the BUS27 and the decoder 31, and outputs terminals to the coil 130. Each transistor 52 to 57 is controlled so that a drive current flows from O1 to the output terminal O2.
In the flowchart and the following description, turning on the driver 50 means putting the driver 50 in an on state for supplying a drive current to the coil 130 of the first motor 13, and turning off the driver 50 means turning the driver 50 on. It means that 50 is turned off so as not to supply the drive current to the coil 130 of the first motor 13.

Next, the CPU 23 executes step S12 and determines whether or not the on-time is equal to or greater than a predetermined threshold value t1. The CPU 23 determines NO in step S12 and continues the determination process in step S12 until the on-time reaches the threshold value t1 or more.
On the other hand, when the on time becomes the threshold value t1 or more, the CPU 23 determines YES in step S12 and executes the process of step S13.
The predetermined threshold value t1 is an on state of the driver 50 in order to prevent the driver 50 from repeatedly turning on and off frequently and increasing the current consumption due to the through current and charge / discharge current generated at that time. This is the minimum time to continue, and is set in advance.

In step S13, the CPU 23 determines whether or not the current I flowing through the coil 130 exceeds the upper limit target current value Imax_O1. The CPU 23 determines NO in step S13 and continues the determination process in step S13 until the current I exceeds the upper limit target current value Imax_O1.
On the other hand, when the current I exceeds the upper limit target current value Imax_O1, the CPU 23 determines YES in step S13, and turns off the driver 50 in step S14.

Next, the CPU 23 executes step S15 and determines whether or not the off time is equal to or greater than a predetermined threshold value t2. The CPU 23 determines NO in step S15 and continues the determination process in step S15 until the threshold value t2 or higher is reached.
On the other hand, when the off time becomes the threshold value t2 or more, the CPU 23 determines YES in step S15 and executes the process of step S16.
The predetermined threshold value t2 is the minimum time for the driver 50 to continue in the off state in order to prevent the driver 50 from repeatedly turning on and off, as in the case of the threshold value t1.

In step S16, the CPU 23 determines whether or not the current I flowing through the coil 130 is smaller than the lower limit target current value Imin_O1. The CPU 23 determines NO in step S16 and continues the determination process in step S16 until the current I becomes smaller than the lower limit target current value Imin_O1.
On the other hand, when the current I becomes smaller than the lower limit target current value Imin_O1, the CPU 23 determines YES in step S16 and executes the process of step S17.

In step S17, the CPU 23 determines whether or not the toff time, which is the duration after the driver 50 is turned off, is equal to or greater than a predetermined threshold value, that is, whether or not the rotor 133 is rotated by 180 °, which is a unit amount. .. If the toff time is less than the threshold value t3, the CPU 23 determines NO in step S17, returns to step S11, and repeats the above process.
On the other hand, when the toff time is equal to or greater than the threshold value t3, the CPU 23 determines YES in step S17 and executes the process of step S18.
The predetermined threshold value t3 may be set in advance by obtaining the toff time when the rotor 133 is rotated by 180 °, which is a unit amount, in an experiment or the like.

In step S18, the CPU 23 has an absolute value of the difference between the drive pulse length T1 at the current polarity, that is, the first polarity and the drive pulse length T2 at the immediately preceding polarity, that is, the second polarity, at a predetermined threshold value t4 or more. Judge whether or not.
If the CPU 23 determines YES in step S18, the CPU 23 executes the process of step S19, and if it determines NO in step S18, the CPU 23 executes the process of step S20.
In step S19, the CPU 23 executes the process of changing the target current value. That is, as described above, when the difference in the drive pulse lengths at each polarity is equal to or greater than the predetermined threshold value t4, it is highly possible that the external magnetic field H3 is applied and affected. Therefore, in step S19, the CPU 23 changes the target current value in order to reduce fluctuations in the on-time and off-time due to the influence of the application of the external magnetic field H3. Specifically, the target current value is varied based on the ratio between the current drive pulse length T1 at the first polarity and the drive pulse length T2 at the immediately preceding second polarity, and is supplied to the coil 130. By making the drive current easier or lesser to flow, it is possible to prevent erroneous detection of rotation of a unit amount of the rotor 133 and to rotate the rotor 133 normally.
The predetermined threshold value t4 may be set by obtaining each drive pulse length when the operation of the rotor 133 is affected in an experiment in which an external magnetic field is applied in advance.

Therefore, in step S19, the CPU 23 sets the proportionality constant to α, the offset amount to b, and sets the current value obtained by (T1 / T2) α × Imax_O1 + b to the corrected Imax_O1. Further, Imin_O1 is obtained by subtracting ΔI, which is a fixed value, from the corrected Imax_O1.
Here, when the drive pulse length T1 at the first polarity this time is shorter than the drive pulse length T2 at the immediately preceding second polarity, (T1 / T2) is less than 1, so the corrected Imax_O1 And Imin_O1 are smaller values than before the correction. When Imax_O1 and Imin_O1 become small values, the upper limit of the drive current supplied to the rotor 133 becomes lower in the next first polarity, so that the drive current becomes smaller. Then, the drive pulse length T1, which is the time required for the rotor 133 to rotate by a unit amount, becomes longer and approaches the drive pulse length in the steady state, so that the possibility of erroneously detecting the rotation of the rotor 133 by a unit amount decreases.
On the other hand, when the drive pulse length T1 at the first polarity this time is longer than the drive pulse length T2 at the immediately preceding second polarity, (T1 / T2) is larger than 1, so that Imax_O1 after correction, Imin_O1 has a larger value than that before the correction. When Imax_O1 and Imin_O1 become large values, the upper limit of the drive current supplied to the rotor 133 becomes high in the next first polarity, so that the drive current easily flows. Then, the drive pulse length T1, which is the time required for the rotor 133 to rotate by a unit amount, becomes shorter and approaches the drive pulse length in the steady state, so that the possibility of erroneously detecting the rotation of the rotor 133 by a unit amount decreases.

The CPU 23 executes step S20 and switches to the second polarity when the target current value is changed in step S19 and when NO is determined in step S18. Then, the CPU 23 ends the drive control process of the first polarity in step S10, and executes the processes after step S5 in FIG.

[Second polarity drive control]
Next, the second polarity drive control in step S30 will be described with reference to the flowchart of FIG. In the second polarity drive control, the same processing as that of the first polarity drive control will be simplified.
When the CPU 23 executes the second polarity drive control in step S30, the CPU 23 executes step S31 and turns on the driver 50 as shown in FIG. At this time, in order to turn on the driver 50 with the second polarity, the CPU 23 outputs the gate signals P1, P2, N1, N2, N3, N4 via the BUS27 and the decoder 31, and outputs terminals to the coil 130. Each transistor 52 to 57 is controlled so that a drive current flows from O2 to the output terminal O1.

Then, the CPU 23 sequentially executes steps S32 to S37. Steps S32, S34, S35, and S37 are the same processes as in steps S12, S14, S15, and S17 of the first polarity drive control. Further, steps S33 and S36 are the same processes as in steps S13 and S16 of the first polarity drive control except that the upper limit target current value Imax_O2 and the lower limit target current value Imin_O2 are used.

If the CPU 23 determines NO in step S37, the CPU 23 returns to step S31 and repeats the above process. On the other hand, if the CPU 23 determines YES in step S37, the CPU 23 executes the process of step S38.

In step S38, the CPU 23 has the absolute value of the difference between the drive pulse length T2 at the current polarity, that is, the second polarity, and the drive pulse length T1 at the immediately preceding polarity, that is, the first polarity, at a predetermined threshold value t4 or more. Judge whether or not.
If the CPU 23 determines YES in step S38, the CPU 23 executes the process of step S39, and if it determines NO in step S38, the CPU 23 executes the process of step S40.
In step S39, the CPU 23 executes the process of changing the target current value. That is, as described above, when the difference in the drive pulse lengths at each polarity is equal to or greater than the predetermined threshold value t4, it is highly possible that the external magnetic field H3 is applied and affected. Therefore, in step S39, the CPU 23 changes the target current value based on the ratio of the drive pulse length T2 at the current second polarity and the drive pulse length T1 at the immediately preceding first polarity, and the coil. By making the drive current supplied to the 130 flow easier or less, it is possible to prevent erroneous detection of rotation of a unit amount of the rotor 133 and to rotate the rotor 133 normally.

Therefore, in step S39, the CPU 23 sets the proportionality constant to α, the offset amount to b, and the current value obtained by (T2 / T1) α × Imax_O2 + b to the corrected Imax_O2. Further, Imin_O2 is obtained by subtracting ΔI, which is a fixed value, from the corrected Imax_O2.
Here, when the drive pulse length T2 at the second polarity this time is shorter than the drive pulse length T1 at the immediately preceding first polarity, (T2 / T1) is less than 1, so the corrected Imax_O2 , Imin_O2 is a smaller value than before the correction. When Imax_O2 and Imin_O2 become small values, the upper limit of the drive current supplied to the rotor 133 becomes lower in the next second polarity, so that the drive current becomes smaller. Then, the drive pulse length T2, which is the time required for the rotor 133 to rotate by a unit amount, becomes longer and approaches the drive pulse length in the steady state, so that the possibility of erroneously detecting the rotation of the rotor 133 by a unit amount decreases.
On the other hand, when the drive pulse length T2 at the second polarity this time is longer than the drive pulse length T1 at the immediately preceding first polarity, (T2 / T1) is larger than 1, so that the corrected Imax_O2, Imin_O2 has a larger value than that before the correction. When Imax_O2 and Imin_O2 become large values, the upper limit of the drive current supplied to the rotor 133 becomes high in the next second polarity, so that the drive current easily flows. Then, the drive pulse length T2, which is the time required for the rotor 133 to rotate by a unit amount, becomes shorter and approaches the drive pulse length in the steady state, so that the possibility of erroneously detecting the rotation of the rotor 133 by a unit amount decreases.
The constants α and b may be set according to the specifications of the electronic clock 1 and the like, and may be set so as to reduce the difference between the drive pulse lengths T1 and T2.

The CPU 23 executes step S40 and switches to the first polarity when the target current value is changed in step S39 and when it is determined to be NO in step S38. Then, the CPU 23 ends the drive control process of the second polarity in step S30, and executes the processes after step S5 in FIG.

Here, the drive pulse lengths T1 and T2 are times from the start of each drive control process in steps S10 and S30 to the polarity switching process in steps S20 and S40, and are measured using a timer (not shown). Then, the CPU 23 stores and updates the latest drive pulse lengths T1 and T2 in a memory (not shown). These timers and memories may be provided inside the IC 20 or may be provided outside. For the first time when the drive pulse lengths T1 and T2 are not stored, the initial value may be left unchanged without changing the target current value.

As described above, the CPU 23 is a driver according to the result of comparing the current value detected by the target current value setting unit for setting the target current value and the current detection circuit 60 which is the current detection unit with the target current value. It functions as a driver control unit that controls the 50 to an on state or an off state, a polarity switching unit that alternately switches the polarity of the drive current between the first polarity and the second polarity, and an external magnetic field detection unit that detects an external magnetic field.
Further, the CPU 23, BUS 27, and the first motor control circuit 30A constitute a clock motor control circuit.

According to the first embodiment as described above, the following effects can be obtained.
According to the present embodiment, when the external magnetic field H3 is applied, the target current value is changed, so that the drive pulse lengths T1 and T2 in the first polarity and the second polarity become extremely short. , It is possible to prevent it from becoming long, and it is possible to control the drive pulse length to be close to that during steady drive. Therefore, the fluctuation of the on time and the off time can be reduced, the rotation angle of the rotor 133 can be estimated normally, and the rotor 133 can be rotated normally.
Therefore, the fast-forwarding hand of the second hand 3 can be continued even if it is affected by the external magnetic field H3.

Since the CPU 23 determines the influence of the external magnetic field H3 based on the absolute value of the difference between the drive pulse lengths T1 and T2, it can accurately detect that the external magnetic field H3 is applied without using a special sensor.

The CPU 23 determines the influence of the external magnetic field in steps S18 and S38 each time the drive control process at each polarity is executed, and if there is an influence, obtains the corrected target current value by calculation in steps S19 and S39. Therefore, the target current value can be changed accurately even if the influence of the external magnetic field changes. Therefore, even if it is affected by an external magnetic field, the first motor 13 can be driven at high speed, and the hand can be moved reliably and accurately without stopping the second hand 3.

The CPU 23, which is the target current value setting unit, calculates the upper limit target current value and then subtracts the fixed value ΔI from the upper limit target current value to obtain the lower limit target current value. It is possible to prevent a large change in the timing of detecting whether or not each condition of polarity switching is met. Therefore, in addition to being able to reliably rotate the rotor 133, the rotation frequency of the rotor 133, that is, the drive frequency of the first motor 13 can also be made constant.

[Second Embodiment]
Next, the electronic clock of the second embodiment will be described. In the second embodiment, the rotor 133 is normally operated by changing the target current value and controlling the drive current supplied to the coil 130 by changing ΔI, which is the difference between the upper limit target current value and the lower limit target current value. It is something to rotate.
Therefore, in the second embodiment, as shown in FIGS. 13 and 14, in the drive control process of the first polarity and the drive control process of the second polarity, only the process of changing the target current values in steps S19B and S39B is performed. It differs from the first embodiment.

In the drive control of the first polarity of step S10B shown in FIG. 13, steps S11 to S18 and S20 are the same as those of the first embodiment shown in FIG. 11, and thus the description thereof will be omitted. On the other hand, if YES is determined in step S18, step S19B is executed in the second embodiment.
In step S19B, the CPU 23 sets the current drive pulse length at the first polarity as T1, the immediately preceding drive pulse length at the second polarity as T2, the proportionality constant as β, and the offset amount as c. T1 / T2) The value obtained by β × ΔI + c is set to ΔI after correction. The upper limit target current value Imax_O1 is set to a fixed value, and the lower limit target current value Imin_O1 is set by subtracting the corrected ΔI from the fixed value Imax_O1.
Here, when the drive pulse length T1 at the first polarity this time is shorter than the drive pulse length T2 at the immediately preceding second polarity, (T1 / T2) is less than 1, so that the corrected ΔI Is a smaller value than before the correction. When ΔI becomes a small value, the range between the lower limit target current value Imin_O1 and the upper limit target current value Imax_O1 becomes smaller, and the drive current supply time to the rotor 133 becomes shorter in the next first polarity. Therefore, the drive pulse length T1, which is the time required for the rotor 133 to rotate by 180 °, which is a unit amount, becomes long and approaches the drive pulse length in a steady state, so that the rotation of the rotor 133 by a unit amount may be erroneously detected. Also declines.
On the other hand, when the drive pulse length T1 at the first polarity this time is longer than the drive pulse length T2 at the immediately preceding second polarity, (T1 / T2) is larger than 1, so that the corrected ΔI is , It becomes a large value compared to before the correction. When ΔI becomes a large value, the range between the lower limit target current value Imin_O1 and the upper limit target current value Imax_O1 becomes larger, and the drive current supply time to the rotor 133 becomes longer in the next first polarity. Therefore, the drive pulse length T1 which is the time required for the rotor 133 to rotate by 180 °, which is a unit amount, becomes short and approaches the drive pulse length in the steady state, so that the rotation of the rotor 133 by a unit amount may be erroneously detected. Also declines.

In the drive control of the second polarity of step S30B shown in FIG. 14, steps S31 to S38 and S40 are the same as those of the first embodiment shown in FIG. 12, so the description thereof will be omitted. On the other hand, if YES is determined in step S38, in the second embodiment, step S39B is executed.
In step S39B, the CPU 23 sets the drive pulse length at the current second polarity to T2, the drive pulse length at the immediately preceding first polarity to T1, the proportionality constant to β, and the offset amount to c. T2 / T1) The value obtained by β × ΔI + c is set to ΔI after correction. The upper limit target current value Imax_O2 is set to a fixed value, and the lower limit target current value Imin_O2 is set by subtracting the corrected ΔI from the fixed value Imax_O2.
Here, when the drive pulse length T2 at the second polarity this time is shorter than the drive pulse length T1 at the immediately preceding first polarity, (T2 / T1) is less than 1, so that the corrected ΔI Is a smaller value than before the correction. When ΔI becomes a small value, the range between the lower limit target current value Imin_O2 and the upper limit target current value Imax_O2 becomes smaller, and the drive current supply time to the rotor 133 also becomes shorter in the next second polarity. Therefore, the drive pulse length T2, which is the time required for the rotor 133 to rotate by 180 °, which is a unit amount, becomes long and approaches the drive pulse length in a steady state, so that the rotation of the rotor 133 by a unit amount may be erroneously detected. Also declines.
On the other hand, when the drive pulse length T2 at the second polarity this time is longer than the drive pulse length T1 at the immediately preceding first polarity, (T2 / T1) is larger than 1, so that the corrected ΔI is , It becomes a large value compared to before the correction. When ΔI becomes a large value, the range between the lower limit target current value Imin_O1 and the upper limit target current value Imax_O1 becomes larger, and in the next second polarity, the supply time of the drive current to the rotor 133 also becomes longer. Therefore, the drive pulse length T2, which is the time required for the rotor 133 to rotate 180 °, which is a unit amount, becomes short and approaches the drive pulse length in a steady state, so that the rotation of the rotor 133, which is a unit amount, may be erroneously detected. Also declines.

According to the second embodiment as described above, the same effect as that of the first embodiment can be obtained, and the following effects can be further obtained.
According to the second embodiment, when the external magnetic field H3 is applied, ΔI is changed to change the range between the upper limit target current value and the lower limit target current value, so that the first polarity and the second are changed. It is possible to prevent the drive pulse lengths T1 and T2 at the same polarity from becoming extremely short or long, and it is possible to control the drive pulse length to be close to that during steady drive. Therefore, the fluctuation of the on time and the off time can be reduced, the rotation angle of the rotor 133 can be estimated normally, and the rotor 133 can be rotated normally.
Therefore, the fast-forwarding hand of the second hand 3 can be continued even if it is affected by the external magnetic field H3.

Since the CPU 23, which is the target current value setting unit, sets the upper limit target current value and the lower limit target current value by varying ΔI, the circuit configuration can be simplified as compared with the first embodiment.

In steps S19B and S39B of the second embodiment, the upper limit target current value is set as a fixed value and the lower limit target current value is changed according to the fluctuation of ΔI, but the lower limit target current value is set as a fixed value and the variation of ΔI. The upper limit target current value may be changed accordingly. Further, the center value of the upper limit target current value and the lower limit target current value may be set as a fixed value, and both the upper limit target current value and the lower limit target current value may be changed according to the fluctuation of ΔI.

[Modification example]
It should be noted that the present disclosure is not limited to each of the above-described embodiments, and modifications, improvements, etc. to the extent that the object of the present disclosure can be achieved are included in the present disclosure.
In each of the above embodiments, in steps S19, S19B, S39, and S39B, the upper limit target current value and the lower limit target current value are calculated and changed, but a table in which the level of the external magnetic field and the target current value are associated with each other is prepared in advance. It may be created and the target current value may be selected and set using the table. For example, the level of the external magnetic field is determined depending on which of the plurality of preset determination ranges the absolute value of the difference between the drive pulse lengths T1 and T2 corresponds to, and the upper limit target current value and the lower limit target current value are determined for each level. If a table in which is set or ΔI is set is prepared, the target current value can be obtained according to the absolute value of the difference between the drive pulse lengths T1 and T2. If the target current value is set using such a table, the circuit can be simplified as compared with the case of calculating as in each of the above-described embodiments.

Further, in each of the above-described embodiments, the detection of the external magnetic field and the processing of changing the target current value are performed each time the first polarity and the second polarity are switched. However, the detection of these external magnetic fields and the target current are performed. The value change process may be performed only once at the first time when the first motor 13 is driven in fast forward, or may be performed a plurality of times, for example, five times, every time the polarity is switched.

In the above embodiment, the external magnetic field is detected by comparing the drive pulse lengths T1 and T2, but the external magnetic field may be detected by the number of times of turning on and the number of times of turning off during the drive control processing at each polarity, or the on time. The external magnetic field may be detected depending on the off time or off time. Further, a magnetic sensor may be incorporated in the electronic timepiece 1 to detect an external magnetic field. Whether these external magnetic field detection methods also contribute to or hinder the rotation of the rotor by detecting the difference between the state at the first polarity and the state at the second polarity. Can be determined.

In the first embodiment, ΔI, which is the difference between the upper limit target current value and the lower limit target current value, is set as a fixed value, but ΔI may also be a variable value. For example, as in the first embodiment, the upper limit target current value may be calculated, ΔI as in the second embodiment may be calculated, and the lower limit target current value may be calculated using the calculated upper limit target current value and ΔI. .. By calculating both the target current value and ΔI in this way, the influence of the external magnetic field can be more strongly canceled during the next drive control with the same polarity.
Further, the method of setting the target current value may be changed according to the level of the applied external magnetic field. For example, when the applied external magnetic field is at a low level, the setting methods of steps S19 and S39 of the first embodiment are executed, and when the applied external magnetic field is at a medium level, steps S19B of the second embodiment are executed. The setting method of S39B may be executed, and if the applied external magnetic field is at a high level, the setting method of calculating both the target current value and ΔI may be executed.

In the above embodiment, the polarity is switched when the off time corresponds to a predetermined condition, but the present invention is not limited to this. That is, the polarity may be switched when the on-time meets a predetermined condition.

In the above embodiment, the forward rotation drive, that is, the drive for rotating the second hand 3 clockwise has been described, but the present invention is not limited to this. That is, the above embodiment can also be applied to reverse drive, that is, drive to rotate the second hand 3 counterclockwise.

In the above embodiment, the case where the stopwatch mode is selected has been described, but the present invention is not limited to this. That is, it is also applicable in the time difference correction mode, the time correction mode, and the hand position detection mode. In the time difference correction mode, the time correction mode, and the hand position detection mode, the above embodiments may be applied when the second hand 3 is fast-forwarded, and when the minute hand 4 or the hour hand 5 is fast-forwarded, the second motor 14 is used. The second motor control circuit 30B that controls the drive of the above operation may be made to perform the above operation.

The target current value setting unit is not limited to setting both the upper limit current value and the lower limit current target value. For example, when the driver control unit controls to turn off the driver when the current value flowing through the coil exceeds the upper limit target current value and turn on the driver after a predetermined time has elapsed after switching to this off state. The target current value setting unit may set only the upper limit target current value.

[Summary of this disclosure]
The clock motor control circuit of the present disclosure is a clock motor control circuit that controls a motor having a coil and a rotor, and is in an on state in which a drive current is supplied to the coil and an off state in which the drive current is not supplied. A controlled driver, a current detection unit that detects the current value flowing through the coil, a target current value setting unit that sets a target current value, and the current value and the target current value detected by the current detection unit. By comparison, the driver control unit that controls the driver to the on state or the off state according to the result of the comparison, and the polarity switching that alternately switches the polarity of the drive current between the first polarity and the second polarity. The target current value setting unit includes a unit and an external magnetic field detection unit that detects an external magnetic field, and is characterized in that the target current value setting unit changes the target current value when the external magnetic field is detected by the external magnetic field detection unit. And.
According to the clock motor control circuit of the present disclosure, the target current value setting unit changes the target current value when an external magnetic field is detected, so that the driver control unit reduces the influence of the external magnetic field. Can be controlled. Therefore, in the first polarity and the second polarity, the drive of the rotor can be controlled in a state close to the steady drive that is not affected by the external magnetic field, the rotation angle of the rotor can be estimated normally, and the rotor can be rotated normally. The fast-forward hand movement of the pointer can be continued even under the influence of an external magnetic field.

In the clock motor control circuit of the present disclosure, the target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and the driver control unit sets the current value as the upper limit. When the target current value is exceeded, the driver is turned off, and when the current value is less than the lower limit target current value, the driver is turned on, and the external magnetic field detector detects the outside. It is determined in which of the first polarity and the second polarity the magnetic field contributes to the rotation of the rotor, and the target current value setting unit determines whether the external magnetic field contributes to the rotation of the rotor in the first polarity. If it is determined that the current contributes to the rotation of the rotor, the upper limit target current value and the lower limit target current value at the next first polarity are reduced, and the external magnetic field causes the rotation of the rotor at the second polarity. When it is determined to contribute, it is preferable to reduce the upper limit target current value and the lower limit target current value at the next second polarity.
According to the clock motor control circuit of the present disclosure, when it is determined that the external magnetic field contributes to the rotation of the rotor in either the first polarity or the second polarity, the upper limit target current at that polarity is determined. Since the value and the lower limit current target value are made small, the drive current supplied to the coil at that polarity can be made small. Therefore, it is possible to prevent the drive current from becoming too large when the currents are synergistic due to the external magnetic field, and to bring the rotation of the rotor closer to that during steady drive. Therefore, the rotation angle of the rotor can be estimated normally, the rotor can be rotated normally, and the fast-forward hand movement of the pointer can be continued even if it is affected by an external magnetic field.

In the clock motor control circuit of the present disclosure, the target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and the driver control unit sets the current value as the upper limit. When the target current value is exceeded, the driver is turned off, and when the current value is less than the lower limit target current value, the driver is turned on, and the external magnetic field detector detects the outside. It is determined in which of the first polarity and the second polarity the magnetic field inhibits the rotation of the rotor, and the target current value setting unit determines whether the external magnetic current inhibits the rotation of the rotor in the first polarity. When it is determined that the rotation of the rotor is hindered, the upper limit target current value and the lower limit target current value at the next first polarity are increased, and the external magnetic field causes the rotation of the rotor at the second polarity. When it is determined to inhibit, it is preferable to increase the upper limit target current value and the lower limit target current value at the next second polarity.
According to the motor control circuit for a clock of the present disclosure, when it is determined that an external magnetic field hinders the rotation of the rotor at either the first polarity or the second polarity, the upper limit target current at that polarity is determined. Since the value and the lower limit current target value are increased, the drive current supplied to the coil at that polarity can be increased. Therefore, it is possible to prevent the drive current from becoming too small when the current is canceled by the external magnetic field, and to bring the rotation of the rotor closer to that during steady drive. Therefore, the rotation angle of the rotor can be estimated normally, the rotor can be rotated normally, and the fast-forward hand movement of the pointer can be continued even if it is affected by an external magnetic field.

In the clock motor control circuit of the present disclosure, the target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and the driver control unit sets the current value as the upper limit. When the target current value is exceeded, the driver is turned off, and when the current value is less than the lower limit target current value, the driver is turned on, and the external magnetic field detector detects the outside. It is determined in which of the first polarity and the second polarity the magnetic field contributes to the rotation of the rotor, and the target current value setting unit determines whether the external magnetic field contributes to the rotation of the rotor in the first polarity. When it is determined that it contributes to the rotation of the rotor, the difference between the upper limit target current value and the lower limit target current value at the next first polarity is reduced, and the external magnetic field causes the rotor at the second polarity. When it is determined that the current contributes to the rotation of the current, it is preferable to reduce the difference between the upper limit target current value and the lower limit target current value at the next second polarity.
According to the motor control circuit for a clock of the present disclosure, if it is determined that an external magnetic field contributes to the rotation of the rotor at either the first polarity or the second polarity, the upper limit target current at that polarity is determined. Since the difference between the value and the lower limit current target value is made small, the time during which the drive current supplied to the coil flows at that polarity can be shortened. Therefore, it is possible to prevent the drive current from becoming too large when the currents are synergistic due to the external magnetic field, and to bring the rotation of the rotor closer to that during steady drive. Therefore, the rotation angle of the rotor can be estimated normally, the rotor can be rotated normally, and the fast-forward hand movement of the pointer can be continued even if it is affected by an external magnetic field.

In the clock motor control circuit of the present disclosure, the target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and the driver control unit sets the current value as the upper limit. When the target current value is exceeded, the driver is turned off, and when the current value is less than the lower limit target current value, the driver is turned on, and the external magnetic field detector detects the outside. It is determined in which of the first polarity and the second polarity the magnetic field inhibits the rotation of the rotor, and the target current value setting unit determines whether the external magnetic current inhibits the rotation of the rotor in the first polarity. When it is determined that the rotation of the rotor is hindered, the difference between the upper limit target current value and the lower limit target current value at the next first polarity is increased, and the external magnetic field causes the rotor at the second polarity. When it is determined that the rotation of the current is hindered, it is preferable to increase the difference between the upper limit target current value and the lower limit target current value at the next second polarity.
According to the motor control circuit for a clock of the present disclosure, when it is determined that an external magnetic field hinders the rotation of the rotor at either the first polarity or the second polarity, the upper limit target current at that polarity is determined. Since the difference between the value and the lower limit current target value is made large, the time for the drive current supplied to the coil to flow at that polarity can be lengthened. Therefore, it is possible to prevent the drive current from becoming too small when the current is canceled by the external magnetic field, and to bring the rotation of the rotor closer to that during steady drive. Therefore, the rotation angle of the rotor can be estimated normally, the rotor can be rotated normally, and the fast-forward hand movement of the pointer can be continued even if it is affected by an external magnetic field.

In the clock motor control circuit of the present disclosure, the external magnetic field detecting unit detects the external magnetic field based on the difference between the driving time of the motor at the current polarity and the driving time of the motor at the immediately preceding polarity. It is preferable to detect it.
Since the external magnetic field is detected based on the difference in driving time between the front and rear polarities, it is possible to accurately detect that an external magnetic field has been applied without using a special sensor.

In the clock motor control circuit of the present disclosure, the external magnetic field detection unit detects the external magnetic field when the drive time of the motor at the current polarity is shorter than the drive time of the motor at the immediately preceding polarity. Is preferably determined to contribute to the rotation of the rotor at this polarity.
If the drive time of the motor at this polarity is shorter than at the time of the previous polarity, the rotor is likely to rotate in this polarity, so the current synergizes due to the influence of the external magnetic field, and the external magnetic field rotates the rotor. It can be easily determined that it contributes to.

In the clock motor control circuit of the present disclosure, the external magnetic field detection unit detects the external magnetic field when the drive time of the motor at the present polarity is longer than the drive time of the motor at the immediately preceding polarity. Is preferably determined to inhibit the rotation of the rotor at this polarity.
If the drive time of the motor at this polarity is longer than that at the previous polarity, the rotor is difficult to rotate in this polarity, so the current cancels out due to the influence of the external magnetic field, and the external magnetic field rotates the rotor. Can be easily determined to inhibit.

In the clock motor control circuit of the present disclosure, the target current value setting unit has the target current value based on the ratio of the drive time of the motor at the current polarity and the drive time of the motor at the immediately preceding polarity. It is preferable to change.
The degree of influence of the external magnetic field on the rotor can be determined by the difference in the drive time of the motor at each polarity. Therefore, if the target current value is changed based on the ratio of each drive time, the degree of influence of the external magnetic field can be determined. The target current value can be set appropriately.

The movement of the present disclosure is characterized by comprising a motor having a coil and a rotor, and the above-mentioned motor control circuit for a timepiece.
According to the movement of the present disclosure, since the motor control circuit for the timepiece is provided, the drive of the rotor can be controlled in the first polarity and the second polarity in a state close to the steady drive which is not affected by the external magnetic field, and the rotor can be controlled. The rotation angle can be estimated normally, the rotor can be rotated normally, and the fast-forward hand movement of the pointer can be continued even if it is affected by an external magnetic field.

The electronic clock of the present disclosure is characterized by including the above-mentioned movement.
According to the electronic clock of the present disclosure, since the movement is provided, the drive of the rotor can be controlled in the first polarity and the second polarity in a state close to the steady drive which is not affected by the external magnetic field, and the rotation angle of the rotor can be adjusted. It can be estimated normally, the rotor can be rotated normally, and the fast-forward hand movement of the pointer can be continued even if it is affected by an external magnetic field.

The control method of the electronic clock of the present disclosure is a control method of an electronic clock including a motor having a coil and a rotor, and is an on state in which a drive current is supplied to the coil and an off state in which the drive current is not supplied to the coil. The rotor is rotated based on the result of comparison between the current value flowing through the coil and the target current value, and when the rotor is rotated by a predetermined amount, the polarity of the drive current is changed to the first polarity and the second polarity. It is characterized in that the target current value is changed when an external magnetic field is detected by alternately switching to the polarity.
According to the control method of the electronic clock of the present disclosure, since the target current value is changed when an external magnetic field is detected, the rotor drive is affected by the external magnetic field in the first polarity and the second polarity. It can be controlled in a state close to that during steady drive. Therefore, the rotation angle of the rotor can be estimated normally, the rotor can be rotated normally, and the fast-forward hand movement of the pointer can be continued even if it is affected by an external magnetic field.

1 ... Electronic clock, 2 ... Dial, 3 ... Second hand, 4 ... Minute hand, 5 ... Hour hand, 7 ... A button, 8 ... B button, 10 ... Movement, 11 ... Crystal oscillator, 12 ... Battery, 13 ... 1st Motor, 14 ... 2nd motor, 20 ... IC, 21 ... Oscillation circuit, 22 ... Dividing circuit, 23 ... CPU, 24 ... ROM, 26 ... Input circuit, 27 ... BUS, 30A ... 1st motor control circuit, 30B ... 2nd motor control circuit, 31 ... decoder, 50 ... driver, 60 ... current detection circuit, 62 ... first reference voltage generation circuit, 63 ... second reference voltage generation circuit, 130 ... coil, 131 ... stator, 133 ... rotor.

Claims (12)

A watch motor control circuit that controls a motor with a coil and rotor.
A driver controlled to an on state in which a drive current is supplied to the coil and an off state in which the drive current is not supplied,
A current detection unit that detects the value of the current flowing through the coil, and
The target current value setting unit that sets the target current value, and
A driver control unit that compares the current value detected by the current detection unit with the target current value and controls the driver to the on state or the off state according to the result of the comparison.
A polarity switching unit that alternately switches the polarity of the drive current between the first polarity and the second polarity,
Equipped with an external magnetic field detector that detects an external magnetic field,
The target current value setting unit is a clock motor control circuit, characterized in that the target current value is changed when the external magnetic field is detected by the external magnetic field detection unit. In the clock motor control circuit according to claim 1,
The target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and sets the target current value.
The driver control unit puts the driver in the off state when the current value exceeds the upper limit target current value, and puts the driver in the on state when the current value becomes less than the lower limit target current value. ,
The external magnetic field detecting unit determines in which of the first polarity and the second polarity the detected external magnetic field contributes to the rotation of the rotor.
The target current value setting unit is
When it is determined that the external magnetic field contributes to the rotation of the rotor in the first polarity, the upper limit target current value and the lower limit target current value in the next first polarity are reduced.
When it is determined that the external magnetic field contributes to the rotation of the rotor in the second polarity, the upper limit target current value and the lower limit target current value in the next second polarity are reduced. Motor control circuit for watches. In the clock motor control circuit according to claim 1,
The target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and sets the target current value.
The driver control unit puts the driver in the off state when the current value exceeds the upper limit target current value, and puts the driver in the on state when the current value becomes less than the lower limit target current value. ,
The external magnetic field detecting unit determines in which of the first polarity and the second polarity the detected external magnetic field inhibits the rotation of the rotor.
The target current value setting unit is
When it is determined that the external magnetic field inhibits the rotation of the rotor at the first polarity, the upper limit target current value and the lower limit target current value at the next first polarity are increased.
When it is determined that the external magnetic field inhibits the rotation of the rotor at the second polarity, the upper limit target current value and the lower limit target current value at the next second polarity are increased. Motor control circuit for watches. In the clock motor control circuit according to claim 1,
The target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and sets the target current value.
The driver control unit puts the driver in the off state when the current value exceeds the upper limit target current value, and puts the driver in the on state when the current value becomes less than the lower limit target current value. ,
The external magnetic field detecting unit determines in which of the first polarity and the second polarity the detected external magnetic field contributes to the rotation of the rotor.
The target current value setting unit is
When it is determined that the external magnetic field contributes to the rotation of the rotor in the first polarity, the difference between the upper limit target current value and the lower limit target current value in the next first polarity is reduced.
When it is determined that the external magnetic field contributes to the rotation of the rotor in the second polarity, the difference between the upper limit target current value and the lower limit target current value in the next second polarity shall be reduced. A motor control circuit for watches that features. In the clock motor control circuit according to claim 1,
The target current value setting unit sets an upper limit target current value and a lower limit target current value as the target current value, and sets the target current value.
The driver control unit puts the driver in the off state when the current value exceeds the upper limit target current value, and puts the driver in the on state when the current value becomes less than the lower limit target current value. ,
The external magnetic field detecting unit determines in which of the first polarity and the second polarity the detected external magnetic field inhibits the rotation of the rotor.
The target current value setting unit is
When it is determined that the external magnetic field inhibits the rotation of the rotor at the first polarity, the difference between the upper limit target current value and the lower limit target current value at the next first polarity is increased.
When it is determined that the external magnetic field inhibits the rotation of the rotor at the second polarity, the difference between the upper limit target current value and the lower limit target current value at the next second polarity shall be increased. A motor control circuit for watches that features. In the clock motor control circuit according to any one of claims 1 to 5.
The external magnetic field detecting unit detects the external magnetic field based on the difference between the driving time of the motor at the current polarity and the driving time of the motor at the immediately preceding polarity. Control circuit. In the clock motor control circuit according to claim 6,
When the drive time of the motor at the current polarity is shorter than the drive time of the motor at the immediately preceding polarity, the external magnetic field detection unit detects the external magnetic field to rotate the rotor at the current polarity. A motor control circuit for a watch, which is characterized by determining that it contributes. In the clock motor control circuit according to claim 6,
When the drive time of the motor at the current polarity is longer than the drive time of the motor at the immediately preceding polarity, the external magnetic field detection unit detects the external magnetic field to rotate the rotor at the current polarity. A motor control circuit for a clock, which is characterized by determining that it interferes. The clock motor control circuit according to any one of claims 1 to 8.
The target current value setting unit is for watches, characterized in that the target current value is changed based on the ratio of the drive time of the motor at the current polarity and the drive time of the motor at the immediately preceding polarity. Motor control circuit. With a motor with a coil and a rotor,
The clock motor control circuit according to any one of claims 1 to 9.
A movement characterized by being equipped with. An electronic timepiece comprising the movement according to claim 10. A method of controlling an electronic clock equipped with a motor having a coil and a rotor.
The rotor is rotated by switching between an on state in which the drive current is supplied to the coil and an off state in which the drive current is not supplied to the coil, based on the result of comparison between the current value flowing through the coil and the target current value. death,
After the rotor has rotated a predetermined amount, the polarity of the drive current is switched alternately between the first polarity and the second polarity.
A method for controlling an electronic timepiece, which comprises changing the target current value when an external magnetic field is detected.

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