JP3239858B2 - Electronic device and control method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device having a stepping motor, such as a timing device, and a control method therefor, and more particularly to an electronic device capable of rapidly moving a stepping motor and a control method therefor.

[0002]

2. Description of the Related Art A stepping motor is a pulse motor,
It is also called a stepping motor, a stepping motor or a digital motor, and is a motor driven by a pulse signal that is frequently used as an actuator of a digital control device. 2. Description of the Related Art In recent years, small electronic devices suitable for carrying have been developed, and small and lightweight stepping motors have been often used as these actuators. A typical example of such an electronic device is a clock device such as an electronic timepiece, a time switch, or a chronograph.

As shown in FIG. 7, a stepping motor 10 used in this time counting device or the like has a magnetically saturated portion 1 in which a two-pole magnetized disk-shaped rotor 13 has a notch-like concave outside.
7, the rotor 13 is rotated by a driving pulse of an appropriate frequency such as 1 Hz, and the hands can be moved by the driving force. I have. In order to eliminate hand movement errors, it is important to check whether or not the rotor 13 has been normally rotated by the drive pulse. For this reason, the drive coil as shown in FIG. Current or voltage detected.

[0004] As shown in the figure, a current (back-induced current) reversely induced due to the rotation of the rotor 13 is substantially opposite to the driving pulse DP when passing through a position approximately 90 degrees from the stable position. A first peak PM1 appears. Further, when the rotor 13 moves, it passes through the position A where the back induced current becomes 0, and passes through the stable position B on the reverse pole side rotated by 180 degrees, which is the destination (reverse pole side). A large first peak PP1 on the same pole side appears. Then, rotor 1
With the shaking (vibration) until 3 stops stably, the second
Peaks PM2 and PP2 occur.

The first peak PM1 or PP1 has a high intensity but is affected by the transient current TW of the drive pulse DP and the like, so that it is difficult to temporally separate the drive pulse DP from the first peak PM1 or PP1. . For this reason, in the conventional normal hand operation, the second peak PM2 or PP2, which is low in intensity but easy to separate, is used for rotation detection, and a method such as chopper amplification by a chopper pulse to increase the intensity is used. Has been adopted.

[0006]

In recent years, various functions have been incorporated into a time measuring device such as a wristwatch device. One of the functions is to automatically move a stepping motor at a higher speed than during normal hand operation. There is a function to set the time manually or manually. When performing fast-forward in which the stepping mower is moved at a high speed, it is necessary to supply a fast-forward drive pulse having a shorter interval (cycle) than a normal drive pulse. Furthermore, in order to set the time, it is necessary to drive the hand so that there is no hand movement error during fast-forwarding, that is, no rotation error of the rotor. For this purpose, it is necessary to determine the presence or absence of rotation of the rotor 13 as early as possible, and to capture the first peaks PM1, PP1 or a phenomenon related thereto, for example, a phenomenon in which the polarity of the back induced current is reversed. Is desirable. For this reason, it has been considered that a detection coil is wound around the stator 12 separately from the drive coil to detect a counter-induced current generated in the detection coil. If the detection coil is separated from the driving coil in terms of a circuit, the influence of a transient current or the like accompanying the driving pulse is reduced, so that the first peaks PM1 and PP1 or a phenomenon related thereto can be easily captured.

However, as shown in FIG. 8, a counter-induced current flows through the detection coil, and thus a magnetic field is generated in a direction that hinders the rotation of the rotor 13. For this reason, the detection coil becomes an electromagnetic brake for the movement of the rotor 13, and it is necessary to increase the effective power of the drive pulse so as to obtain a drive force in consideration of the brake force. Therefore, power consumption for driving the stepping motor increases. In particular, when fast-forwarding, the rotational speed of the rotor 13 increases, so that the counter-induced current generated by the detection coil also increases, and the braking force of the detection coil also increases accordingly. Therefore, in order to overcome this braking force and increase the speed, a drive pulse having a larger effective power is required, and the power consumption also increases. Also,
As the speed increases, the braking force also increases, making it difficult to increase the speed.

Therefore, in the present invention, in an electronic device having a stepping motor, by providing a detection coil, the presence or absence of rotation of the rotor can be checked at the earliest possible timing, and a brake by a counter-induced current flowing through the detection coil is provided. It is an object of the present invention to provide an electronic device capable of alleviating the phenomenon and a control method thereof. It is another object of the present invention to provide an electronic device capable of reducing power consumption when the stepping motor is fast-forwarded and capable of performing the fast-forward at high speed and stably.

[0009]

For this reason, in an electronic apparatus having a stepping motor according to the present invention, when a drive pulse is supplied, a detection coil is opened.
Then, the braking force due to the back induced current is reduced by short-circuiting at the timing of detecting the position of the rotor. That is, the electronic apparatus of the present invention includes a stepping motor in which a multipolar magnetized rotor is rotationally driven in a stator having a driving coil and a detecting coil, and a driving pulse for driving the rotor with respect to the driving coil. Drive control means capable of supplying
Position detection means capable of detecting the counter-induced power induced in the detection coil of the stator due to the rotation of the rotor, and opening the detection coil while the drive pulse is being supplied,
Detecting coil control means for detecting the position of the rotor by short-circuiting the detecting coil. Further, according to the present invention, there is provided a control method of an electronic device having a stepping motor in which a multi-polarized rotor is rotationally driven in a stator having a driving coil and a detecting coil. A driving step of supplying a driving pulse for driving the rotor, and a position detecting step of short-circuiting a detecting coil and detecting a counter-induced power induced in the detecting coil of the stator by rotation of the rotor. ing.

[0010] If the detection coil is opened while the drive pulse is being supplied, no counter-induced current flows through the detection coil. Therefore, while the drive pulse is being supplied, the detection coil can be prevented from acting as an electromagnetic brake. On the other hand, by short-circuiting the detection coil after the supply of the drive pulse, a counter-induced power is generated in the detection coil if the rotor is rotating. Since the detection coil is separated from the drive coil, the influence of the transient current due to the drive pulse is small. For this reason, it is easy to detect a phenomenon such as a peak of the back induced power generated in the detection coil or a zero cross related thereto. Therefore, the presence or absence of rotation of the rotor can be determined at an early stage by determining the first peak or a phenomenon related thereto. As described above, according to the electronic device or the control method of the electronic device of the present invention, the braking action of the detection coil is reduced, so that the stepping motor can be driven by a drive pulse having a small effective power, and the Can determine the rotation of the rotor at an early timing. Therefore, the rotor can be rotated at high speed with low power consumption, and fast-forwarding can be performed stably.

As described above, the electronic apparatus and the control method thereof according to the present invention are suitable for supplying a stepping motor with a fast-forward driving pulse having a short interval with respect to a normal driving pulse to perform fast-forwarding. On the other hand, when the rotor is driven by a normal drive pulse, it is desirable that the rotor be driven by a drive pulse having a low effective power and be rotated at a predetermined angle, for example, 180 degrees in a timepiece, and then be stabilized once at that position. . On the other hand, when fast-forwarding,
It is desirable that the rotor rotate continuously without stabilizing at a certain position. For this purpose, in an electronic device in which the drive control means can supply both a normal drive pulse and a fast-forward drive pulse with a short interval, the drive control means further supplies a fast-forward drive pulse. It is desirable to open the driving coil after the supply, and short-circuit the driving coil after supplying the normal driving pulse. Further, in a control method of an electronic device capable of supplying a normal drive pulse and a fast-forward drive pulse having a shorter interval than the normal drive pulse in the drive step, after supplying the fast-forward drive pulse, the drive coil And a step of short-circuiting the drive coil after supplying a normal drive pulse.

By short-circuiting the drive coil after supplying a normal drive pulse, a counter-induced current flows through the drive coil, so that the drive coil can act as an electromagnetic brake. In this case, a counter-induced current also flows through the driving coil, and the normal drive pulse has a long interval, so that there is room for detecting the rotation of the rotor using the second peak of the counter-induced current. Therefore, the presence or absence of rotation of the rotor can be determined based on the back induced current flowing through the driving coil.
Of course, the detection coil can be short-circuited to increase the braking force, and the presence or absence of rotation of the rotor can be determined from the counter-induced current flowing through the detection coil.

On the other hand, if the driving coil is opened after supplying the driving pulse for fast-forward, the back induced current does not flow through the driving coil, so that the driving coil can be prevented from acting as an electromagnetic brake. Therefore, the force acting as a brake against the movement of the rotor is weakened and the loss is reduced, so that the rotor can be rotated at a high speed with a drive pulse having a small effective power. As described above, even if the driving coil is opened, the presence or absence of rotation of the rotor can be determined based on the counter-induced current flowing through the detection coil by short-circuiting the detection coil.

As described above, in the electronic device and the control method thereof according to the present invention, the driving coil is separated from the detecting coil, and the driving coil is supplied with the driving pulse when the rotor is rotated at a high speed. Only when it is connected, the detection coil can be short-circuited only when the detection of the back induced current is required. Therefore, it is possible to prepare a coil having the number of windings or other conditions suitable for driving and detection, and to prevent each coil from acting as an electromagnetic brake when not used for the purpose. When driven by a normal drive pulse, the drive coil can be short-circuited and used as an electromagnetic brake.

Further, when the drive pulse is turned off, spikes, which are high-frequency noises, occur in the detection coil. Therefore, it is desirable to provide a mask period in which both the driving coil and the detection coil are open.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings. FIG. 1 shows an example of a timing device such as a wristwatch device using a stepping motor.
The timekeeping device 1 includes a stepping motor 10, a control device 20 for driving the stepping motor 10, a wheel train 50 for transmitting the movement of the stepping motor 10, and a second hand 61, a minute hand 62 and an hour hand driven by the wheel train 50. 63 is provided. The stepping motor 10 includes a driving coil 11 that generates a magnetic force by a driving pulse supplied from a control device 20, a stator 12 that is excited by the driving coil 11,
Rotor 1 rotated by a magnetic field excited inside the rotor
The rotor 13 is a stepping motor 10 of the PM type (permanent magnet rotating type) in which the rotor 13 is constituted by a disk-shaped two-pole permanent magnet. The stator 12 is provided with a magnetic saturation portion 17 so that different magnetic poles are generated in the respective phases (poles) 15 and 16 around the rotor 13 by the magnetic force generated by the driving coil 11. Further, an inner notch 18 is provided at an appropriate position on the inner periphery of the stator 12 to regulate the rotation direction of the rotor 13, so that cogging torque is generated so that the rotor 13 stops at an appropriate position. ing.

The rotation of the rotor 13 of the stepping motor 10 is controlled by the fifth wheel & pinion 5 meshed with the rotor 13 through a pinion.
1, fourth wheel 52, third wheel 53, second wheel 54, minute wheel 5
The power is transmitted to each hand by a train wheel 50 including the wheel 5 and the hour wheel 56. A second hand 61 is connected to the axis of the fourth wheel & pinion 52, a minute hand 62 is connected to the second wheel & pinion 54, and an hour hand 63 is connected to the hour wheel & pinion 56. The hands indicate the time. It is of course possible to connect a transmission system (not shown) for displaying the date and the like to the wheel train 50.

In this timekeeping device 1, in order to display the time by the rotation of the stepping motor 10, a signal of a reference frequency is counted (timed) and the drive pulse is supplied to the stepping motor 10 periodically. The control device 20 of the present example for controlling the stepping motor 10 includes a pulse synthesizing circuit 22 that generates a reference pulse having a reference frequency and a pulse signal having a different pulse width and timing by using a reference oscillation source 21 such as a crystal oscillator. A drive control circuit 25 for controlling the stepping motor 10 based on various pulse signals supplied from the synthesis circuit 22 and a detection circuit 75 for detecting rotation of the rotor 13 are provided.

The drive control circuit 25 supplies a drive pulse DP having a frequency of 1 Hz to the drive coil 11 via the drive circuit to drive the drive rotor 13 of the stepping motor 10 for normal hand movement; It has a function of supplying a drive pulse JP for fast forward driving the rotor 13 in a forward or reverse direction at a speed faster than the speed for normal hand movement. Further, when the driving rotor 13 does not rotate, a function of outputting an auxiliary pulse having a larger effective power than the driving pulse, a function of outputting a regenerative pulse for regenerating the energy of the rotor following the auxiliary pulse, a function of outputting the driving pulse, It also has a function to adjust the effective power.

The stepping motor 10 has a drive circuit 30 operating based on a control signal from the drive control circuit 25.
, A normal driving pulse DP or a fast-forward driving pulse JP is supplied. The drive circuit 30 includes an n-channel MOS 33a and a p-channel M
An OS 32a and a bridge circuit composed of an n-channel MOS 33b and a p-channel MOS 32b are provided, so that the power supplied from the power supply 41 to the drive coil 11 of the stepping motor 10 can be controlled.

In the coil portion 19 of the stepping motor 10 of this embodiment, a detection coil 71 is wound together with the drive coil 11, and both ends of the detection coil 71 are connected in parallel with p-channel MOSs 73a and 73b. It is connected to the connection circuit 72. MOS of this connection circuit 72
73a and 73b are controlled by control signals φt1 and φt2 from the detection coil control circuit 76 of the detection circuit 75. As will be described in detail later, after the drive pulse JP for fast-forward is supplied, the detection coil 71 is short-circuited to generate counter-induced power, and chopped to amplify the counter-induced voltage. The chopper-amplified reverse induced voltage is supplied to the position detection circuit 77 of the detection circuit 75, and the level of the peak value is determined.
Alternatively, the position of the rotor 13 can be determined by a method such as capturing a phenomenon (zero cross) in which the voltage value is inverted. Further, the position detection circuit 77 is also connected to the drive coil 11, and can determine the position of the rotor 13 using the back induced voltage generated in the drive coil 11.

FIG. 2 shows a cross section along the longitudinal direction of the coil portion 19 employed in the stepping motor 10 of the present embodiment. In the coil section 19 of this example, a detection coil 71 is wound around a magnetic core 19a, and a drive coil 11 is wound outside the detection coil 71. The detection coil 71 wound inside is aligned and wound so that the surface is substantially uniform and flat. Even if the two coils 71 and 11 are wound coaxially, the driving coil wound outside is used. The performance of the use coil 11 does not deteriorate. Of course, it is also possible to wind the drive coil 11 inside, and in this case, too, the variation in resistance of the detection coil wound outside is suppressed, and the like.
It is desirable that the inner drive coil 11 be aligned and wound so that stable detection of back induced power is possible. Although the drive coil 11 and the detection coil 71 can be separately wound, it is possible to reduce the installation space of the coil by winding the drive coil 11 and the detection coil 71 coaxially. And the stepping motor 10 can be compactly assembled.

FIG. 3 shows an outline of a control method of the drive coil 11 and the detection coil 71 in the control device 20 of the present embodiment. First, in step 81, the detection coil is opened by the detection coil control circuit 76, and the drive control circuit 25 supplies a normal drive pulse DP or a fast-forward drive pulse JP having an appropriate effective power at an appropriate timing. I do. The drive control circuit 25 determines in step 8
In 2, the subsequent control is changed depending on the type of the drive pulse to be supplied. First, after supplying the normal drive pulse DP, the drive coil 11 is short-circuited in step 83.
Then, a counter-induced current caused by the rotation of the rotor 13 flows through the driving coil 11 and is used as an electromagnetic brake.

On the other hand, after supplying the drive pulse JP for fast-forward, the drive coil 11 is opened in step 84 so that the drive coil 11 does not act as an electromagnetic brake. Further, in step 85, after a mask period during which both the driving coil 11 and the detection coil 71 are opened, in step 86, the detection coil control circuit 76 short-circuits the detection coil and generates counter-induced power.

In step 87, the position detecting circuit 77
To determine the position of the rotor 13 and determine whether the rotor 13 has rotated normally. The position detection circuit 77 determines the position of the rotor 13 based on the back induced power generated in the driving coil 11 when the normal driving pulse DP is supplied, and determines the position of the rotor 13 when the fast-forward driving pulse JP is supplied. Based on the back induced power generated by the detection coil 71, the rotor 13
Judge the position.

FIGS. 4 and 5 show each of the drive circuit 30 and the connection circuit 72 in order to realize the above control process.
The manner of controlling the OS is shown in a timing chart. FIG. 4 is a timing chart when a normal drive pulse DP is supplied. Before the normal drive pulse DP1 is supplied at the time t1, p constituting the drive circuit 30
The control signals .phi.p1 and .phi.p2 for channel MOSs 32a and 32b are low,
And 32b are on. Therefore, the driving coil 11 is short-circuited by the MOSs 32a and 32b. N-channel MO constituting drive circuit 30
The control signals φn1 and n2 in S33a and 33b are at a low level, and the MOSs 33a and 33b are off. Further, control signals φt1 and t2 of p-channel MOSs 73a and 73b forming connection circuit 72 are at a high level, and these MOSs 73a and 73b are off. Therefore, the detection coil 71 is open.

Drive pulse DP for normal hand movement of timekeeping device 1
Is supplied to the stepping motor 10 at 1 Hz. Therefore, at time t1 when the timing becomes 1 Hz, the control signal φp2 is set to the high level to turn off the MOS 32b.
The control signal φn2 is set to a high level to turn on the MOS 33b. As a result, the MOS 32a and the MOS 33b are turned on, the power corresponding to the drive pulse DP1 is supplied to the drive coil 11, and the rotor 13 rotates. During this time, since the control signals φt1 and φt2 are held at a high level, the detection coil 71 remains open, and no counter-induced current flows through the detection coil 71.

When the driving pulse DP1 is supplied, at time t
2, since the control signals φp2 and φn2 go low, the MOS 32b is turned on and the MOS 33b is turned off. Therefore, the driving coil 11 is short-circuited, and a counter-induced current flows with the movement of the rotor 13, so that the driving coil 11 functions as an electromagnetic brake. Therefore, the rotor 13 can be stabilized at a position after the rotation (a position rotated by 180 degrees). Further, the back-induced voltage or the back-induced current generated in the driving coil 11 after the time t2 is detected by the position detection circuit 77, and it can be determined whether the rotor 13 has normally rotated. When the rotor 13 does not rotate normally, an auxiliary pulse having an effective power larger than the drive pulse DP is supplied to forcibly rotate the rotor 13 and avoid a hand movement error.

During this time, the MOS 73 of the connection circuit 72
a and 73b remain off. Therefore,
In this example, the detection coil 71 is not short-circuited during operation in which the normal drive pulse DP is supplied.
It is not used as an electromagnetic brake or for detection. At appropriate timing after the supply of the drive pulse DP, the control signals φt1 and φt2 may be set to a low level to short-circuit the detection coil 71. In this case, the detection coil 71 can function as an auxiliary electromagnetic brake, and the back-induced voltage or current induced in the detection coil 71 can be detected by the position detection circuit 77. However, the driving coil 11 is also short-circuited, and the counter-induced current or voltage generated in the coil 11 is larger than that generated in the detection coil 71. It is desirable to detect the back induced current or voltage.

At time t3, one second after time t1, the control signals φp1 and φn1 go high, and a drive pulse DP2 having the opposite polarity to that described above is supplied to the stepping motor 10. Therefore, the rotor 13 further rotates 180 degrees. After time t4 after the supply of the drive pulse DP2, the control signals φp1 and φn1 again become low level, so that the drive coil 11 is short-circuited. Therefore, similarly to the above, the rotor 13 is stabilized at the position rotated by 180 degrees,
It can be determined that the motor has reached the position by detecting a back induced current or voltage generated in the driving coil 11. Control signals φp1 and φ
By chopping p2, the driving coil 11
Can be chopper-amplified to further detect the position of the rotor 13.

FIG. 5 is a timing chart when the drive pulse JP for fast forward is supplied. Drive circuit 30
P-channel MOS 32a and MOS 32
When fast-forwarding is started at time t11 in a state where the control signals φp1 and φp2 of “b” are low and the driving coil 11 is short-circuited, the control signals φp2 and φn2 become high, and the MOS 32a and the MOS 33b are turned on. become. As a result, the drive pulse JP1 for fast forward is supplied to the stepping motor 10. During this time, since the control signals φt1 and t2 are held at a high level, the detection coil 71 is in the open state, and the detection coil 71
Does not flow, and does not act as an electromagnetic brake.
When a drive pulse JP1 of a predetermined effective power for fast-forwarding the rotor 13 is supplied to the drive coil 11, a time t
12, the control signal φp1 goes high and the control signal φ
n2 becomes low level, and the driving coil 11 is opened. Therefore, the back induced current does not flow through the driving coil 11 and does not act as an electromagnetic brake.

After time t12, a mask period M during which both the driving coil 11 and the detection coil 71 are open.
At a time t13, the control signals φt1 and φt2 are set to low level, and the MOSs 73a and 73
Turn on b. As a result, the detection coil 71 is short-circuited, and a reverse induced current flows through the detection coil 71. further,
The control signal φt1 is a chopping signal.
S73a chops the counter-induced current flowing through the detection coil 71, and a chopper-amplified counter-induced voltage is obtained. Therefore, the position detection circuit 77 is
The rotor 13 is detected by detecting the back electromotive force generated in the rotor 13.
Can be determined.

FIG. 6 shows that the driving pulse D is applied to the driving coil 11.
The back induced voltage generated in the detection coil 71 when P is supplied is schematically shown. The dashed line indicates the back induced voltage generated when the detection coil is short-circuited, and the solid line indicates the back induced voltage generated when the detection coil is short-circuited after time t13 when the mask period M has elapsed. is there. As can be seen from this figure, by providing the detection coil 71 separately from the drive coil 11, the influence of the transient phenomenon of the drive pulse as shown in FIG. 8 can be reduced. However, if the detection coil 71 is always short-circuited, a counter-induced voltage is generated while the drive pulse JP is being supplied, so that an electromagnetic brake is generated, and a spike occurs when the drive pulse JP is turned on / off. Therefore,
When fast-forwarding, it becomes an obstacle to rotating the rotor 13 at high speed, and it is difficult to detect the position of the rotor 13 immediately after the drive pulse JP is supplied.

On the other hand, if the detection coil 71 is left open and short-circuited at time t13, the detection coil 71 can be prevented from acting as an electromagnetic brake while the drive pulse JP is supplied. By setting the mask period M, the influence of spikes can be suppressed. Further, by short-circuiting the detection coil 71 immediately before the first peak of the back induced power generated in the detection coil (the first peak on the same polarity side as the drive pulse), the peak value can be expanded. Therefore, the position detection circuit 77
When the position of the rotor 13 is detected based on the peak value, the presence or absence of a peak is clarified, so that the position of the rotor 13 can be reliably determined at an early timing. Furthermore, the peak value can be further expanded by chopper-amplifying the back induced voltage. Also, when the position of the rotor 13 is determined by the position detection circuit 77 being reversed by the reverse induced voltage (zero cross), the influence of the spike can be prevented and the peak value can be expanded, so that the timing at which the reverse induced voltage is reversed is clear. Become. Therefore, the position of the rotor 13 can be determined early and clearly.

Further, since the position of the rotor can be detected by using the detection coil 71, the drive coil 11 is opened during the position detection, so that the back induced current can be prevented from flowing through the drive coil 11. Therefore, since the driving coil 11 does not act as an electromagnetic brake, the rotor 13 can be rotated at high speed with little energy.

When the position of the rotor 13 is confirmed by detecting the back induced voltage generated in the detection coil 71, the control signals φt1 and φt2 are set to a high level at time 14 to open the detection coil 71. At the same time, from time t14 to time t
15, the control signal φp2 is set to a low level, and the control signal φ
By setting n1 to a high level, a drive pulse JP2 for fast-forwarding with a reverse polarity to the time t11 is supplied. And the driving coil 1
At a time t16 after a mask period in which both of the detection coil 71 and the detection coil 71 are in the open state, the control signals φt1 and φt2 are set to low level to short-circuit the detection coil 71, and the position of the rotor 13 is detected. By repeating the same control after time t17, fast forward can be performed at high speed while checking the position of the rotor 13.

As described above, in the electronic timepiece 1 and the control method thereof according to the present embodiment, the driving coil 11 and the detecting coil 71 are separately provided, and the detecting coil 71 supplies the driving pulse JP for fast-forwarding and then rotates the rotor. 13 is short-circuited only when confirming the position. Therefore, the detection coil 71 does not interfere with the rotation of the rotor by acting as an electromagnetic brake.Furthermore, at the time of rapid traverse, the influence of the drive pulse is small due to the detection coil provided separately from the drive coil. The rotation of the rotor 13 can be confirmed at an early timing. Therefore, stable fast-forwarding can be performed with little energy. Further, since the drive coil 11 can be opened so as not to act as an electromagnetic brake while the drive pulse JP is not supplied, it is possible to prevent the drive coil 11 from hindering the rotation of the rotor. Therefore, the rotor can be fast-forwarded at high speed with lower power consumption.

As described above, when fast-forwarding, the drive coil is opened when detecting the position of the rotor, and when the drive pulse is supplied, the detection coil is opened. The driving coil 1
For 1, only a condition in which a drive pulse is supplied is taken into consideration, and for example, a condition in which conditions such as a winding diameter or the number of turns are suitable for driving the rotor 13 so that a sufficient magnetic field can be generated can be adopted. Further, when the detection coil 71 employs a coil having a suitable condition such as a winding diameter or the number of turns so that the back induced power is generated to the extent that the back induced power can be detected, and when a back induced current is supplied to detect the position of the rotor. Also, the action as an electromagnetic brake can be minimized. Since the driving coil and the detection coil can be optimized in this way, it is also possible in this regard to reduce power consumption during fast-forwarding.

On the other hand, when a normal drive pulse DP is supplied, the drive coil 11 can be short-circuited and used positively as an electromagnetic brake. As described above, in the present invention, the drive coil and the detection coil provided separately therefrom can be controlled according to the conditions of the normal hand movement and the fast traverse, respectively. It can be performed stably.

The waveforms of the driving pulses DP and JP and other control signals described above are merely examples, and may be adjusted according to the characteristics of the stepping motor 10 employed in the timekeeping device or the configuration of the driving circuit. Of course, it can be transformed. Further, in the above-described example, the present invention is described using a two-phase stepping motor suitable for a timing device as an example. However, it goes without saying that the present invention can be similarly applied to a three-phase or more stepping motor. . Also, the driving method of the stepping motor is not limited to one-phase excitation, but may be two-phase excitation or 1-2-phase excitation. Further, the present invention is not limited to a clock device such as a wristwatch device, but may be applied to a multifunction timepiece such as a chronograph and other electronic devices having a built-in stepping motor.

[0041]

As described above, according to the present invention, when a stepping motor having a driving coil and a detecting coil is driven, when a driving pulse is supplied to the driving coil, the detecting step is performed. The coil is opened to prevent it from acting as an electromagnetic brake. In particular, when the stepping motor is fast-forwarded, the drive coil is opened when detecting the rotor position to minimize the chance of acting as an electromagnetic brake, and the detection coil is short-circuited to detect the rotor position. Can be performed at an early timing. Therefore, the rotor can be rapidly and stably fast-forwarded, and the power consumed at that time can be reduced.

Accordingly, it is possible to provide an electronic device suitable for a timekeeping device having a function of adjusting the time by quickly feeding an hour hand or a minute hand by a stepping motor and a control method therefor.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a timing device including a stepping motor according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a coil unit of the stepping motor shown in FIG.

FIG. 3 is a diagram schematically showing a control method for rotating a rotor by supplying a drive pulse in the timekeeping device shown in FIG. 1;

FIG. 4 is a timing chart showing control when a normal drive pulse is supplied.

FIG. 5 is a timing chart showing control when a driving pulse for fast-forward is supplied.

FIG. 6 is a diagram schematically showing a back induced voltage generated in a detection coil.

FIG. 7 is a diagram schematically showing how a rotor rotates in a stator.

8 is a diagram schematically showing a change in the current of the driving coil when the rotor rotates as shown in FIG. 7, and a change in the counter-induced current generated with the change.

[Explanation of symbols]

 1. Timing device 10. Stepping motor 11. Driving coil 12. Stator 13. Rotor 17. Magnetic saturation section 19. Coil section 20. Control device 21. Crystal oscillator 22 .. Pulse Synthetic circuit 25 Drive control circuit 30 Drive circuit 41 Power supply 50 Wheel train 51 Fifth wheel 52 Fourth wheel 53 Third wheel 54 Second wheel 55 Day The reverse wheel 56 ・ ・ Hour wheel 61 ・ ・ Second hand 62 ・ ・ Minute hand 63 ・ ・ Hour hand 71 ・ ・ Detection coil 72 ・ ・ Connection circuit 75 ・ ・ Detection circuit 76 ・ ・ Detection coil control circuit 77 ・ ・ Position detection circuit

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G04C 3/14 H02P 8/00

Claims (6)

(57) [Claims] 1. A stepping motor in which a multi-polar magnetized rotor is rotationally driven in a stator having a driving coil and a detecting coil, and a driving pulse for driving the rotor is supplied to the driving coil. Possible drive control means, position detection means capable of detecting the counter-induced power induced in the detection coil by rotation of the rotor, and opening the detection coil while the drive pulse is supplied, Thereafter, a detection coil control unit for detecting the position of the rotor by short-circuiting the detection coil. 2. The drive control means according to claim 1, wherein said drive control means is capable of supplying a fast-forward drive pulse having a short interval with respect to a normal drive pulse, and further comprising, after supplying said fast-forward drive pulse. An electronic device, wherein the drive coil is opened, and after the normal drive pulse is supplied, the drive coil is short-circuited. 3. The detection coil control means according to claim 2, wherein the detection coil control means short-circuits the detection coil after a lapse of a mask period in which both the driving coil and the detection coil are opened. Electronics. 4. A method for controlling an electronic device having a stepping motor in which a multipolar magnetized rotor is rotationally driven in a stator having a driving coil and a detecting coil, wherein the detecting coil is opened. A drive step of supplying a drive pulse to drive the rotor to the drive coil; and a position detection step of short-circuiting the detection coil and detecting a counter-induced power induced in the detection coil by rotation of the rotor. And a control method for an electronic device having: 5. The method according to claim 4, wherein in the driving step,
It is possible to supply a normal drive pulse and a drive pulse for fast forward having a shorter interval than the normal drive pulse, and after supplying the drive pulse for fast forward, a step of opening the drive coil; and And a step of short-circuiting the drive coil after supplying the drive pulse. 6. The control method for an electronic device according to claim 5, wherein between the driving step and the position detecting step, a mask period in which the driving coil and the detecting coil are both opened is provided.