JP2014181945A - Electronic timepiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analog electronic timepiece having a system for preventing malfunction due to an electromagnetic action between stepping motors, without requiring an extra space and components even when the plurality of stepping motors are mounted on the timepiece, the system being applicable to even a small-sized timepiece without imposing any configuration of the stepping motors causing the layout difficulty.SOLUTION: While at least one stepping motor 100 out of a plurality of proximate stepping motors is driven, coil ends of the other suspended stepping motors 200 are put in a high impedance state so as to prevent a current from flowing to the coils of the suspended stepping motors, thereby generating no magnetic flux and reducing malfunction of the suspended stepping motors 200.

Description

  The present invention relates to an analog electronic timepiece that displays time and the like using a plurality of stepping motors, and more particularly, to reduction of malfunction caused by magnetic noise between adjacent stepping motors.

  With the increase in functionality of analog electronic timepieces, it is not uncommon for a plurality of stepping motors to be arranged in one analog electronic timepiece. At the same time, wristwatches have been demanded to be thin and small, and there is a trade-off between the increase in watch volume and the demand for thinness and miniaturization due to multifunctional and multi-stepping motors. For this reason, a plurality of stepping motors arranged in a space-saving electronic timepiece are close to each other, and electromagnetic interference may occur between adjacent stepping motors, causing an unexpected malfunction. There was a thing.

Hereinafter, problems of the prior art will be described with reference to the drawings.
FIG. 2 is an explanatory diagram regarding the arrangement of a plurality of stepping motors and the influence thereof, showing the problems of the prior art.

In FIG. 2, reference numeral 100 denotes a first stepping motor, which is a general two-pole stepping motor for a watch, and includes a stator 101, a rotor 102, and a coil 103. Reference numeral 200 denotes a second stepping motor, which is disposed adjacent to the first stepping motor 100. The second stepping motor 200 has the same configuration as that of the first stepping motor 100, and includes a stator 201, a rotor 202, and a coil 203.
The rotors 102 and 202 drive a display pointer (not shown) via a wheel train (not shown).

  Reference numeral 300 denotes an IC for driving and controlling the first stepping motor 100 and the second stepping motor 200, and an output driver circuit 302 a is similarly connected to both ends 103 a and 103 b of the coil 103 of the first stepping motor 100. A circuit 302 b is connected to both ends 203 a and 203 b of the coil 203 of the second stepping motor 200. Note that the driver circuits 302a and 302b are simplified for the sake of explanation. The driver circuits 302a and 302b are arranged in the IC 300, but are illustrated separately for convenience.

  Subsequently, the operation will be described. Here, a case where the first stepping motor 100 is driven by the IC 300 will be described. Specifically, a drive pulse is output from the driver circuit 302a, whereby a current flows through the coil 103, and a magnetic flux 502 is generated in the stator 101, whereby the rotor 102 rotates, and a train wheel (not shown) is rotated. Thus, a pointer (not shown) is driven.

  On the other hand, when a plurality of stepping motors are used in the electronic timepiece, the coils of the stopping stepping motors other than the driving stepping motor are normally short-circuited in order to exert an electromagnetic holding force. In FIG. 2, the driver circuit 302b plays the role.

Therefore, as shown in FIG. 2, the magnetic flux 104, which is a part of the magnetic flux generated from the driving first stepping motor 100, is stopped in the vicinity of the driving first stepping motor 100. Then, an electromotive force is generated in the coil 203 of the stopped second stepping motor 200 by electromagnetic induction.
When a current flows through the coil 203 of the stopped second stepping motor 200 by this electromotive force, a secondary magnetic flux 501 is generated in the coil 203 of the stopped second stepping motor 200. Then, the secondary magnetic flux 501 flows through the stator 201 of the stopped second stepping motor 200.
When the secondary magnetic flux 501 flows through the stator 201, the second stepping motor 200 is driven in a pseudo manner, leading to a malfunction such as an unillustrated pointer driven by the rotor 202.

  As a means to solve the above problems, the distance between the stepping motors is increased to reduce the influence of the magnetic force, or a magnetic shield plate is inserted between the stepping motors to stop the magnetic flux of the stepping motor on the driving side. For example, the stepping motors may be blocked from reaching a certain stepping motor, or the stepping motors may be arranged at positions where the stepping motors are difficult to act magnetically.

  For example, the technique disclosed in Patent Document 1 is based on the arrangement of a magnetic material having a higher magnetic permeability or lower magnetic resistance than a stepping motor component as a magnetic shield plate around the stepping motor. Magnetic noise is prevented from entering.

  Further, the technique disclosed in Patent Document 2 is arranged so that the coil axis directions of the two stepping motors arranged inside the timepiece are almost perpendicular to each other, thereby making it less susceptible to the influence of magnetic fluxes generated from each other. ing.

JP 55-10532 A Japanese Patent No. 2653364

However, the above conventional solution has the following problems.
In Patent Document 1, since it is necessary to newly arrange the magnetic shield member around the stepping motor, it is necessary to secure not only the arrangement space of the magnetic shield member but also the space and structure for fixing the magnetic shield member. The area occupied by the stepping motor becomes large, and particularly when a plurality of stepping motors are arranged on the same plane, the space becomes insufficient and the layout becomes very difficult. Furthermore, since the number of magnetic shield members and fixed parts is required by the number of stepping motors, the cost increases.

  Also, in Patent Document 2, it is necessary to arrange the coil axis directions of a plurality of stepping motors so that they are perpendicular to each other in a plane. Parts cannot be arranged in the area, and a region where parts can be arranged freely is markedly large. The layout becomes very difficult because there are fewer. In particular, a small timepiece may not have enough space and a layout may not be established.

  Therefore, even when a plurality of stepping motors are mounted on a timepiece, the present invention does not require new space or parts, and does not impose an arrangement of stepping motors that makes layout difficult. An object of the present invention is to provide an analog electronic timepiece having a method for preventing malfunction caused by electromagnetic action between stepping motors, which can be applied to a timepiece.

In order to solve the above problems and achieve the object, the present invention provides:
It has a plurality of step motors consisting of a rotor, coils and a stator,
A plurality of motor drivers corresponding to each of the plurality of step motors and having an output connected to a coil end of each step motor to drive the plurality of step motors;
A pulse generation circuit for generating various pulse signals for driving the step motors;
In addition to the output of the drive pulse from the pulse generation circuit, an electronic timepiece having a drive control circuit for performing various controls on the motor drivers,
The drive control circuit includes:
While driving one of the step motors by a drive pulse output from the motor driver,
At least one of the other stepping motors being stopped is
At least one of the motor driver outputs connected to the coil end is in an open state.

  The analog electronic timepiece according to the present invention has an effect of reducing malfunction caused by electromagnetic action generated between a plurality of stepping motors in the timepiece movement while minimizing the timepiece movement size and the number of parts used. .

It is explanatory drawing regarding arrangement | positioning of several stepping motors, and its influence about 1st Embodiment of this invention. It is explanatory drawing regarding arrangement | positioning of several stepping motors, and its influence about a prior art. It is a block diagram which shows the circuit structure which drives the several stepping motor in 1st Embodiment of this invention. It is an example of the circuit block diagram of the driver circuit which drives the stepping motor in 1st Embodiment of this invention. It is an example of the table which showed the switching pattern of the driver circuit in 1st Embodiment of this invention. It is a time chart which shows an example of a drive pulse of a stepping motor, a current waveform of a stepping motor, and a coil open section in a 2nd embodiment of the present invention. It is a figure for demonstrating the influence between stepping motors when the some stepping motor is arrange | positioned in the vicinity in 3rd Embodiment of this invention. FIG. 10 is an example of a circuit configuration diagram of a driver circuit that drives a stepping motor according to Modification 1;

Exemplary embodiments of an analog electronic timepiece according to the invention will be described below in detail with reference to the accompanying drawings.

[First Embodiment]
First, a first embodiment showing a basic configuration of the present invention will be described with reference to the drawings. In addition, about the same structure as FIG. 2 which demonstrated the prior art, the same number is attached | subjected and detailed description is abbreviate | omitted.

  FIG. 1 is an explanatory diagram regarding the arrangement of a plurality of stepping motors and the influence thereof on the first embodiment. This is the same as FIG. 2 except that the driver circuit 302b is in an open state. Also in this embodiment, the stepping motor to be driven is the first stepping motor 100, and the second stepping motor 200 is stopped during this period. The same applies to the following embodiments.

As described above, the second stepping motor 200 is driven when the first stepping motor 100 is driven.
It has been explained that the secondary magnetic flux 501 generated in the second step leads to a malfunction of the second stepping motor 200 (eg, a pick of a pointer). The secondary magnetic flux 501 is generated when the magnetic flux 104 which is a part of the magnetic flux generated when the first stepping motor 100 is driven flows into the coil 203. Furthermore, it occurs because the coil 203 is in a short-circuited state, resulting in a closed circuit configuration.

  Therefore, in the present embodiment, as shown in FIG. 1, by holding at least one of the end portions 203a and 203b of the coil 203 of the stopped second stepping motor 200, the first stepping motor 100 during driving is held. When the magnetic flux 104 of the second stepping motor is interlinked with the coil 203 of the second stepping motor 200 and an electromotive force is generated, a closed circuit is not formed by electrically opening the coil, and no current flows. The generation of the secondary magnetic flux 201 can be suppressed and malfunction can be prevented.

  An effect equivalent to maintaining at least one of the coils 203 of the second stepping motor 200 in an open state is that elements having high resistance characteristics are connected to both ends of the coil 203 of the second stepping motor 200, and the inside of the coil is Since it can be obtained by a method of reducing the flowing current, either of the two methods may be selected depending on the state of the circuit in the timepiece.

  In other words, the “open state” means “to put either one of the coil ends in a floating state” or “insert a high resistance between one of the coil ends and the driver output, It also includes “decreasing the flowing current”. In most embodiments, the former will be described, but a part of the latter will also be described (“Modification 1” described later).

Next, a method for controlling the first stepping motor 100 and the second stepping motor 200 will be described with reference to FIGS. 3, 4, and 5.
FIG. 3 is a block diagram showing a circuit configuration for driving a plurality of stepping motors in the first embodiment of the present invention.

In FIG. 3, reference numeral 300 denotes an IC for driving control as described above, and the first stepping motor 100 and the second stepping motor 200 are driven by the driver circuits 302a and 302b. Reference numeral 306 denotes an oscillation circuit that creates a reference high frequency signal, reference numeral 305 denotes a frequency dividing circuit that converts the reference signal output from the oscillation circuit 306 into an arbitrary frequency, and reference numeral 304 denotes a signal output from the frequency dividing circuit 305. This is a pulse generation circuit that generates an arbitrary drive pulse for driving the stepping motor.
Reference numeral 303 denotes a drive pulse generated by the pulse generation circuit 304 and outputs it to the driver circuits 302a and 302b to drive the first stepping motor 100 and the second stepping motor 200 and to perform various controls on the driver circuits 302a and 302b. Drive control circuit.

  FIG. 4 is an example of a circuit configuration diagram showing a specific configuration of driver circuits 302a and 302b for driving the stepping motor in the first embodiment of the present invention. It is assumed that the driver circuits 302a and 302b have the same configuration. In FIG. 4, reference numerals 402, 403, 404, and 405 denote transistors that switch the current flowing through the coils 103 and 203. Here, 402 and 403 are P-type transistors, and 404 and 405 are N-type transistors. Vdd 406 and Vss 407 are power supply potentials (not shown), Vdd 406 is an upper power supply potential, and Vss 407 is a lower power supply potential.

The P-type transistor 402 and the N-type transistor 404 are connected in series between the upper power supply voltage Vdd406 and the lower power supply voltage Vss407. Similarly, the P-type transistor 403 and the N-type transistor 405 are connected to the upper power supply voltage Vdd406 and the lower power supply voltage Vss407. Are connected in series. The coils 103 and 203 are connected between the connection point between the P-type transistor 402 and the N-type transistor 404 and the connection point between the P-type transistor 403 and the N-type transistor 405.

In addition, a control signal from the drive control circuit 303 is input to each gate terminal of each transistor 402-405, and the state of an output connected to each coil terminal 103a, 103b, 203a, 203b is determined by this control signal. The
FIG. 5 is a table showing a switching pattern of the driver circuit, and is a table showing in what combinations the transistors 402, 403, 404, and 405 are turned on or off.

Next, the operation of the combination of FIG. 5 and the driver circuit of FIG. 4 will be described.
The vertical columns in FIG. 5 indicate whether the transistors 402, 403, 404, and 405 are kept ON or OFF, respectively, and the horizontal row indicates the setting of each transistor in the embodiment of the present invention. Represents a combination.
Normally, when the first stepping motor 100 and the second stepping motor 200 are not operating, as shown in FIGS. 4 and 5A, the P-type transistors 402 and 403 are in the ON state, and the N-type transistors 404 and 405 are in the ON state. Is in the OFF state, the current path of Vdd 406, P-type transistor 402, coil 103 (203), P-type transistor 403, and Vdd 406 is formed, and both ends of coil 103 (203) become Vdd potential and short-circuited. Yes.

When the first stepping motor 100 is driven in this state, as described above, the magnetic flux 104 leaking from the first stepping motor 100 is linked in the coil 203 of the second stepping motor 200 that is stopped and short-circuited. Then, an electromotive force is generated by electromagnetic induction, and a magnetic flux 501 is generated secondaryly (hereinafter, “stepping motor” may be abbreviated as “STM”). Due to this secondary magnetic flux, the STM rotor being stopped is shaken, and the hands of the timepiece driven by this rotor malfunction.
Therefore, by using (b), (c), and (d) described in the second to fourth rows in FIG. 5 for the combination of setting of each transistor in the embodiment of the present invention, the above-described malfunction is prevented. I can do it.

First, the motor operation in the combination shown in FIG.
When the first stepping motor 100 is operated, the coil end of the stopped second stepping motor 200 is turned off with all the P-type transistors 402 and 403 and the N-type transistors 404 and 405 being turned off as shown in FIG. By switching to, both ends 203a and 203b of the coil 203 are electrically opened, and even if the leakage flux of the first stepping motor is linked to the coil of the second stepping motor, current flows by electromagnetic induction. Since there is no path, generation of secondary magnetic flux 501 is suppressed and malfunction is prevented.
Next, the motor operation in the combination of FIG.

  When the first stepping motor 100 operates, the P-type transistor (P1) 402 in the driver circuit of the second stepping motor 200 is set to the ON state, and the other transistors 403, 404, and 405 are set to the OFF state. As a result, electrical conduction is established through the path of Vdd 406, P-type transistor 402, and coil 203, so that one terminal 203 a of coil 203 is connected to Vdd 406. The other terminal of the coil 203b is electrically open because the transistors 403, 404, and 405 are OFF.

Therefore, even if the leakage magnetic flux 104 of the first stepping motor 100 in operation is linked to the coil 203 of the second stepping motor 200, a current flow path due to electromagnetic induction does not occur, so a secondary magnetic flux is not generated. In addition to preventing the rotor from malfunctioning, one of the terminals 203a of the coil 203 can be set at the Vdd potential, so that charges due to static electricity can be discharged to Vdd, and even when electrical noise is superimposed, it can be released to Vdd. Therefore, it can be made strong against electrical disturbance.

Next, the motor operation in the combination of FIG.
When the first stepping motor 100 operates, the P-type transistor (P2) 403 in the driver circuit 302b for the second stepping motor 200 is set to the ON state, and the other transistors 402, 404, and 405 are set to the OFF state. As a result, electrical conduction is established through the path of Vdd 406, P-type transistor 403, and coil 203, so that one terminal 203 b of coil 203 is connected to Vdd 406. The other terminal of the coil 203a is electrically opened because the transistors 402, 404, and 405 are OFF.
That is, the combination of FIG. 5D is the case where the coil terminal in the open state is reversed from the case of FIG. 5C, and the same effect as in FIG. 5C is obtained.

  In creating the release state of the coil 203, which of FIGS. 5B to 5D is selected depends on the shape of the coil, the control specifications, the ease of control of the IC 300, and other influences as appropriate. Consider and select.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. The second embodiment is
In this embodiment, the coil of the stopped stepping motor (hereinafter referred to as “stopped STM”) is opened in at least the drive pulse output section of the driven stepping motor (hereinafter referred to as “driven STM”).

  FIG. 6 is a time chart showing an open section of the coil of the stopped STM according to the second embodiment of the present invention. In FIG. 6, reference numeral 601 denotes a pulse example for driving a stepping motor. Reference numeral 602 denotes a current waveform generated when the rotor is rotated by the stepping motor driving pulse 601.

In order to carry out the present invention, as described in the first embodiment, the coil (the coil 203 in the first embodiment) of the stopped STM (the second stepping motor 200 in the first embodiment) is opened. This can be achieved. However, the stopped STM naturally has a timing to drive, and at that timing, it cannot be opened.
In general, when the coil of the stepping motor is opened, the electromagnetic brake for the rotor is not effective, and the impact resistance performance of the stepping motor is reduced.

  Therefore, as shown in FIG. 6, the time during which the coil (in the first embodiment, the coil 203 in the first embodiment) of the stopped STM (in the first embodiment, the coil 203) is in the open state is set as the operating STM (first In one embodiment, the drive pulse 601 is greatly influenced by the first stepping motor 100) (t1-t2), and the current waveform 602 due to the rotation vibration of the rotor is within the remaining section (t2-t3). While minimizing the time during which the impact resistance is lowered, malfunction due to electromagnetic influence from the STM during operation is prevented.

  In addition, about the open time of the coil of STM during a stop, it is not limited to the form of FIG. In view of safety, a period from a predetermined time before the output (t1) of the drive pulse 601 or after a predetermined time after the remaining period (t3) of the current waveform 602 due to the rotational vibration of the rotor may be included.

  Further, the end point (t3) of the remaining section of the current waveform 602 can be set as appropriate in consideration of the degree of influence of the current waveform 602.

  Furthermore, the current waveform 602 is generated by the free vibration of the rotor, and is considered to have a smaller influence than the drive pulse 601. Therefore, it is good also as only the drive pulse 601 (t1-t2) area as the opening time of the coil of STM during a stop.

[Modification 1]
As is well known, rotation detection of a rotor in a stepping motor is performed by putting one end of a coil into a high impedance state (open state). Therefore, in the stopped STM, when the open state of the coil is created in order to implement the present invention, it is possible to use a circuit for detecting rotation. Specifically, normally, when the rotation is detected, the state shown in FIG. 5C or FIG. 5D is set. Therefore, the open state in the present invention is changed to the state shown in FIG. 5C or FIG. By setting to, it becomes possible to share. As a result, the circuit configuration can be reduced.

  At the time of rotation detection, it is often performed to connect to the power supply potential with a high resistance (generally several tens to several hundreds kΩ) in order to control the peak value of the current waveform. Because of the high resistance, the same effect as the open state in the present invention can be obtained.

  FIG. 8 shows a specific configuration. In FIG. 8, reference numeral 410 denotes a detection resistor for controlling the peak value of the counter electromotive current waveform flowing through the coil 203, and is generally a high resistance of several tens to several hundreds kΩ. Reference numeral 408 denotes a P-type transistor for controlling connection between the detection resistor 410 and the Vdd potential 406, and is controlled by the drive control circuit 306. Note that although there is a similar circuit on the end 203a side, the description is omitted.

  At the time of rotation detection (section t2-t3 in FIG. 6), the P-type transistor 403 is turned off and the 408 is turned on, and the end 203b is connected to the Vdd potential 406 through the detection resistor 410 having a high resistance.

  Even if this circuit is applied to a section excluding t1-t2, for example, the detection resistor 410 has a high resistance, so that the same effect as in the floating case can be obtained.

  Alternatively, the detection resistor 410 may be connected at the time of rotation detection, and the detection resistor 410 may be disconnected at the time of stoppage so as to be in a floating state. In this way, the effects of both techniques can be exhibited more appropriately.

[Modification 2]
As described above, since the electromagnetic brake does not work while the coil of the STM is stopped, the impact resistance performance is lowered. However, during the opening, the rotor vibrates due to an external impact and a back electromotive force is generated. Therefore, by detecting the counter electromotive force due to this external impact and outputting a pulse (lock pulse) for braking the rotor rotation, it is possible to prevent malfunction due to leakage magnetic flux while ensuring impact resistance performance. .

  Note that the detection of the external impact and the braking control by the lock pulse are well known, for example, from Japanese Patent No. 4751573, and therefore detailed description thereof is omitted.

[Third Embodiment]
Next, a third embodiment of the present invention will be described in detail with reference to the drawings. The third embodiment relates to control when there are a plurality of stopped STMs.

As described above, in the stopping STM, the electromagnetic brake does not work while the coil is open, so that the impact resistance performance may be lowered. Therefore, in order to minimize the influence of external impact, not all the stopped STM coils are opened (opened), but only the partially stopped STM coils are opened (opened).

FIG. 7 is an explanatory diagram regarding the arrangement of a plurality of stepping motors and the influence thereof on the third embodiment. 1, a third stepping motor 700 is disposed on the opposite side of the second stepping motor 200 from the first stepping motor 100 and is controlled by the driver circuit 302c. As in FIG. 1, it is assumed that the first stepping motor 100 is driven and the second stepping motor 200 and the third stepping motor 700 are stopped. Further, the illustration of the IC 300 is omitted.
When there are a plurality of stopped STMs in the same watch, only the coil 203 of the second stepping motor 200 that is stopped closest to the operating first stepping motor 100 is opened, and the second stepping motor 200 is opened. The coil 703 of the stopped third stepping motor 700 installed at a position farther from the operating first stepping motor 100 is in a short-circuited state as usual.

  Thereby, the 2nd stepping motor 200 arrange | positioned in proximity to the 1st stepping motor 100 in operation | movement can prevent the malfunctioning by the influence of a secondary magnetic flux by making the coil 203 into an open state. On the other hand, for the stopped third stepping motor 700 installed at a position away from the operating first stepping motor 100 than the second stepping motor 200, it is considered that the influence of the secondary magnetic flux is small. By continuing the short-circuit state of the coil 703, the conventional impact resistance can be maintained.

  Note that the selection method of the stepping motor that opens the coil when there are a plurality of stopped STMs is not limited to the case shown in FIG.

(1) The larger the pointer, the easier it is for the user to find a malfunction. Therefore, when there are a plurality of stopped STMs, the coil of the stepping motor of the rotor to which the largest pointer that is most noticeable by the user during malfunction is attached is opened.

(2) Conversely, the larger the pointer, the more likely the needle jump due to external impact occurs. Therefore, there is an option to watch out for the needle jump due to external impact and not to open the coil of the rotor stepping motor to which the largest pointer is attached.

  Note that it is possible to appropriately select which of (1) and (2) is selected for the stepping motor of the rotor to which the largest pointer is attached in consideration of the specifications of the timepiece and the performance of the stepping motor.

(3) Only the stepping motor equipped with the function of detecting the impact back electromotive force due to the external impact shown in the modified example 2 can be used as the stopped STM that opens the coil of the stopped STM.

100 Stepping motor during driving 101 Stator of driving stepping motor 102 Rotor of driving stepping motor 103 Coil of driving stepping motor 103a Coil terminal piece end 103b of driving stepping motor Coil terminal piece end 104 of driving stepping motor By stepping motor during driving Generated magnetic flux 200 Stopping stepping motor 201 Stopping stepping motor stator 202 Stopping stepping motor rotor 203 Stopping stepping motor coil 203a Stopping stepping motor coil terminal piece end 203b Stopping stepping motor coil terminal piece end 501 Driving Magnetic flux 300 IC generated by leakage magnetic flux from stepping motor
302 Stepping motor driving driver circuit 302a Driving stepping motor driving driver circuit 302b Stopping stepping motor driving driver circuit 302c Stopping stepping motor driving driver circuit 303 Drive control circuit 304 Pulse generation circuit 305 Frequency dividing circuit 306 Oscillation circuit 402 (P1) Motor driver P-type transistor 403 (P2) Motor driver P-type transistor 404 (N1) Motor driver N-type transistor 405 (N2) Motor driver N-type transistor 406 Vdd upper power supply voltage 407 Vss lower power supply voltage 408 P-type transistor 410 for controlling connection between detection resistor 410 and Vdd potential 406 Detection resistor 601 for controlling the peak value of the back electromotive current waveform flowing through coil 203 Motor drive pulse 602 Motor drive Coils of the rotor 703 is stopped in the stepping motor 700 of the stator 702 is stopped in the stepping motor 700 of current waveform 700 is stopped in the stepping motor 701 is stopped in the stepping motor 700 when

Claims (7)

It has a plurality of step motors consisting of a rotor, coils and a stator,
A plurality of motor drivers corresponding to each of the plurality of step motors and having an output connected to a coil end of each step motor to drive the plurality of step motors;
A pulse generation circuit for generating various pulse signals for driving the step motors;
In addition to the output of the drive pulse from the pulse generation circuit, an electronic timepiece having a drive control circuit for performing various controls on the motor drivers,
The drive control circuit includes:
While driving one of the step motors by a drive pulse output from the motor driver,
At least one of the other stepping motors being stopped is
An electronic timepiece characterized in that at least one of the motor driver outputs connected to the coil end is in an open state. As a period for the open state (hereinafter referred to as an open period),
The electronic timepiece according to claim 1, wherein a free vibration period of the rotor after the drive pulse is output is included. While opening one of the motor driver outputs,
It has a rotation detection function to detect rotation by connecting a detection resistor to the motor driver output that has become open.
3. The electronic timepiece according to claim 1, wherein the drive control circuit is in a state in which the detection resistor is disconnected during the open period. 4. An impact detection function for detecting an external impact by detecting a counter electromotive force generated in the rotor due to an external impact in the open period;
4. The brake function according to claim 1, further comprising: a braking function for outputting a braking pulse for braking the rotor to the coil when an impact is detected by the impact detection function. 5. Electronic watch. The stopping step motor closest to the driven step motor is
The electronic timepiece according to claim 1, wherein the electronic timepiece is in an open state. The stopped stepping motor with the largest attached pointer is
The electronic timepiece according to claim 1, wherein the electronic timepiece is in an open state. The stopped stepping motor with the largest attached pointer is
5. The electronic timepiece according to claim 1, wherein the coil end is short-circuited.

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