JPS61116681A - Electronic timepiece - Google Patents

Abstract

PURPOSE:To achieve a lower power consumption of a timepiece with an increase in the effective electrochemical conversion efficiency of a pulse motor, by detecting the rotating operation thereof to control the driving conditions according to the output thereof. CONSTITUTION:A load detection circuit 29 is added to an electronic timepiece which comprising a time reference vibrator 25, a time counting circuit 26 containing an oscillation circuit a frequency dividing circuit and the like and a pulse moor driving circuit 27 for driving the pulse motor 28. Then, after a drive pulse is applied to the motor 28, the circuit 29 turns the electromagnetic drive coil of the motor 28 to the open loop in which the driving conditions of the motor 28 is controlled with a control circuit 30 according to the output of the circuit 29 using induced voltage obtained between coil terminals as detection input signal. The circuit 30 normally perform a control to feed a narrow drive pulse without load and a wide drive pulse with a load. This can achieve a lower power significantly as compared with the case where the pulse motor is always driven by a pulse with the same width.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic timepiece, and more particularly to a motor drive system for an electronic timepiece using a pulse motor in an electric i-shelf conversion mechanism.

An object of the present invention is to increase the effective electromechanical conversion efficiency of such a pulse motor and reduce the power consumption of a watch.

For quartz crystal analog watches, especially wristwatches, which use a crystal oscillator as the time standard and mechanically display seconds, minutes, hours, etc. with hands, etc., the time standard is extremely accurate and the reliability of the displayed time is high. In addition to the yfPt degree of the crystal resonator, which is the time standard, the life of the power supply battery is a major factor. For crystal watches that have an electromechanical conversion mechanism, the power consumption of the electromechanical conversion mechanism is larger than that of the electronic circuit including the oscillation circuit. It is expected to increase battery life. The total current consumption of a circuit using a crystal with an oscillation frequency of several tens of KHz is currently 1
It is less than μA, and CL5μA is also possible and can be further reduced. On the other hand, the current consumption of the converting section is extremely large at 2 to 5 μA, and there is a noticeable imbalance between the current consumption of the circuit section and the converting section.

If the mechanical parts after the converter become larger, the waste flow in the converter will further increase.

The present invention reduces current consumption when a pulse motor is used as a conversion mechanism by controlling motor drive conditions. When determining the pulse motor drive conditions for a portable watch, it is necessary to take into consideration the load conditions and environmental resistance of the mechanical parts after the motor, as well as the drive voltage range. Here, in the design of the conventional pulse motor and the setting of the drive φ, the highest efficiency was obtained at the isometric maximum load when all of the above conditions were taken into consideration. Considering the actual motor load conditions, the mechanical load includes a calendar mechanism that operates intermittently as well as a steady train load. An example of an isometric increase in load due to disturbance during carrying is an increase in equivalent load due to an instantaneous large-load external magnetic field caused by a balancing machine. When a silver battery, a silver chloride battery, or the like is used as the drive voltage, the voltage varies from approximately 1.6 V to 3 V due to an increase in internal resistance, including temperature changes.

However, in reality, the timepiece body is in the isometrically large load state mentioned above only for a very short period of time in a day, and most of the time it is in a static state and in a micro-load state (9). The present invention controls driving conditions according to changes in the value of the load.1
(2) During normal small load (is a small output drive energy supplied to the motor, and if there is an isometric increase in load compared to normal times due to disturbance or other effects, the output will be adjusted to match the increase in load. It supplies drive energy, or provides drive energy equivalent to the maximum rated power output of conventional designs.

Therefore, it is clear that the driving method of the present invention can reduce the average current consumption compared to the current consumption when driving under a conventional constant driving condition, that is, the maximum rated driving condition.

Furthermore, in the present invention, when detecting the load applied to the motor, an isometric load is detected from the rotational state of the rotor.

The rotor rotation detection means uses the induced voltage in the electromagnetic coil caused by the rotation of the rotor to facilitate detection. The design of the detection circuit is greatly simplified. In addition, as will be described later, [a. Braking is applied to rapidly damp the rotor and the pulling position is stabilized when the rotor is stationary.This type of drive method uses reliable all-electronic means without mechanical contacts to achieve equalization and a conversion mechanism. This realizes a stable drive that can deal with variations in type, mass production, etc.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. First, a pulse motor and its operation will be explained in detail, and then examples will be explained in detail.

Figure 1 is an example of a pulse motor for an electronic wristwatch.
In the figure, reference numeral 1 denotes a rotor with a permanent magnet ring magnetized into two poles, and stators 2 and 3 are placed facing each other with this coater 1 in between. Place it on the rolled yoke 5 and 112! The stator consists of a fire.

The stators 2 and 3 are provided with notches 2a and 5a so that the rotor 1 can rotate in a fixed direction.
, 3 (shifted. The broken line indicates the rest position of the rotor magnetic pole. This type of pulse motor has been put into practical use for a long time and was driven by a simple circuit block shown in Fig. 10. is a crystal oscillator, which is driven by an oscillation circuit 11, whose frequency is divided by a divider 12,
18 of an appropriate time width at appropriate time intervals using the waveform shaper 16.
Two pulses with different phases are formed.

As an example, let us consider a pulse of 7.8 m5ec every 2'' and explain this below.
The input is input to a driver 14 and 15 consisting of an inverter, and its output is sent to the terminal 4a of the coil 4.

4b. FIG. 3 is a detailed diagram of a part of this driver. When a signal 18 is applied to the input terminal 16 of one inverter 140, a current flows to the machine indicated by the arrow 19, and conversely, a similar signal flows to the input terminal 17 of the other inverter 150. When a signal is applied, a current flows in a route symmetrical to the arrow 19. That is, by alternately applying signals to the input terminals 16 and 17 of both inverters, the current flowing through one coil 4 can be alternately reversed. Specifically, the current flowing through the coil 4 can be alternately reversed every second. current can be passed through the coil 4. Due to such a drive circuit, N poles and S poles are alternately generated in the stators 2 and 3 of the step motor shown in FIG.
It can be rotated by 800.

And the rotation of this rotor 1 is intermediate 7! 4 via L6
Transferred to Homaresha 7, and not included in the illustration 3 Homaresha, 2
It is transmitted to the @IK, cylinder pinion, hour wheel, calendar mechanism, and operates the indicating mechanism consisting of the hour hand, minute hand, second hand, calendar, etc.

The pulse motor shown in FIG. 1 has been used as a conversion mechanism for electronic wristwatches.

In the drive circuit of FIG. 3, a J-level signal is applied to terminal 17, a signal 18 is applied to terminal 16, and arrow 19
When a current flows through the MOS) transistor 15, a voltage drop based on the driving current occurs due to the channel impedance, and this 1! A signal waveform corresponding to the current can be detected. The current waveform is as shown in FIG. 4, for example.

In Figure 4, the section person is the driving section, which in this case is 7.8m5ec.

The current flowing in this section A is the current consumed by driving the motor. The reason why the current waveform in this section A has a complicated shape as shown in the figure is because it is generated based on the voltage applied by the drive circuit. This is because, in addition to the current, an induced current is superimposed on the coil due to the rotation of the driven rotor. Section B is a section after the drive pulse is applied, and the rotor performs damped vibration due to inertia and magnetic attraction until it stops at a stable position. At this time, the period after applying the drive pulse is the third
P-channel MO8 of drive inverter 14 and 15 in the figure
) Since the transistor is ON, both terminals of the coil 4 are short-circuited via the transistor, and an induced current flows in the coil 4 in response to the movement of the # rotor. This is why the waveform in section B in FIG. 4 is pulsating. Therefore, the shape of this drive current waveform and the induced current waveform after driving can almost correspond to the rotational position of the rotor. Now, waveform 20 and waveform 20' in FIG. 4 are a series of waveforms, This is the case when the load on the rotor is very small. Waveform 22 and waveform 22' are also a series of waveforms, and in this case, the load on the rotor is large and the rotor is close to its operating limit. This is the case when multiplied by . If you observe the current waveform when the load is changed in this way, you will see that the waveform extends to the right as the load increases. This is because the load increases and the rotor rotation slows down. It has been experimentally confirmed that the rotor vibration frequency until it stops at a stable position is low and the SFA is small.If we consider this phenomenon in reverse, the load on the rotor is always in a no-load state. If there is, drive ha/'s @ h 7
．． It is understood that driving can be performed with a pulse width shorter than 8 m5ec. In fact, even if the pulse width is shortened, the motor still operates and the output torque decreases.

This situation is shown in FIG. FIG. 5 shows the output torque characteristic T and the power consumption characteristic when the drive pulse width is changed. The aforementioned drive pulse @ 7.8 m5
ec corresponds to Pz in this figure. That is, at pulse @P2, the output torque is T; and the power consumption is 2. As mentioned above, this output torque T2 is set so as to be able to sufficiently withstand the load encountered by the watch body.

However, if the load on the rotor is small or negligible, the output torque can be small, the drive pulse width can be shortened, and the power consumption can therefore be reduced. For example, if the drive is shifted with a pulse width of P+, the output torque Tl and the power consumption can be reduced to 1 effort. The present invention focuses on this point, and by detecting the load on the rotor, drives with a narrow pulse width when there is no load or a small load, and drives with a wide pulse width when a large load is applied. This is a rational and low-power design. As mentioned before, the overwhelming majority of people are in a no-load state, so the effect of reducing power consumption is very large. For example, as shown in Figure 5, when driving with a pulse width of P+ during no load (20 hours) and with a pulse width of Pz during load (4 hours), and assuming that E1/Iz=%, the average power consumption is = Work x 20 + Work tX4 - Earthwork 2 ->, 58 Work 2. Compared to the conventional method which was driven with the pulse width of Pz at all times, the power consumption is less than 60 inches, resulting in a significant reduction in power consumption.

By the way, although it was mentioned above that the load is detected, it goes without saying that this method of detecting the load is a major point of the present invention. Next, a method for detecting this load will be described. As described above, there is a one-to-one correspondence between the rotor rotational movement and the current waveform. FIG. 6 shows the phase relationship between the ti waveform and the rotor rotation angle. The lower curve in Figure 6 indicates that the rotor advances one step due to the drive pulse and reaches the next pulling position (
180'), and the peak position of the coil current after application of the drive pulse approximately corresponds to when the rotor passes near the pulling position. 6th
The correspondence of the waveforms shown in the figure is shown in Fig. 4 20', 21', 22
It has been confirmed that similar results can be obtained for each waveform of '. This is because current is induced in the electromagnetic coils based on fluctuations in the magnetic field within the stator caused by the vibrations of the rotor magnets.
Since the polarity of the rate of change of the stator internal magnetic field changes before and after centering on [)', 0°), the peak of the coil current corresponds to the pulling position. Furthermore, since the relationship between the motor load and the coil induced current is as shown in FIG. 4, the motor load can be detected from the coil induced current waveform. The rotation angle of the rotor is detected to determine whether the stepping operation of the rotor has been completed by increasing or decreasing the load.

That is, confirmation can be made by detecting the coil induced current.

The present invention takes advantage of these features to supply the necessary drive energy according to the magnitude of the motor load, thereby avoiding unnecessary energy consumption and substantially reducing current consumption. In the present invention, the following steps are implemented to further facilitate signal detection.

The amplitude of the current waveform shown in Figure 4 is extremely small, about 10 to 20 mV at most, and in order to detect the peak of the waveform, a precise circuit is required as a detection circuit, and there are problems such as offset and drift of the detection amplifier circuit. A fine adjustment circuit for is generally required. However, as described above, clock circuits are characterized by low dissipation power, so generally C! Consists of MOEI logic, circuit voltage tSV
It's nearby. Therefore, it is obvious that it is extremely difficult to provide a sophisticated detection circuit and is also disadvantageous in terms of cost. Therefore, in the present invention, in order to facilitate detection, the coil terminals are left open after the motor drive pulse is applied, and the voltage induced in the coil due to rotor vibration is treated as a detection signal. The waveforms shown in Fig. 4, 20' etc. are the third
This is the voltage drop based on the internal impedance of the drive transistor 14 or 15 shown in the figure, and as mentioned above, it is at most about 20 mV (not much more).On the other hand, if the coil terminal is left open, no current will be generated in the coil. A large pulsating current voltage can be obtained at the coil terminals according to changes in magnetic flux caused by the rotation of the rotor magnet.The output varies somewhat depending on the coil inductance, but is generally 500 to 100,100.
The amplitude is delayed to 0 degrees, and the output is 20 to 50 times the amplitude, and the detection means can be designed extremely easily. The instantaneous load detection circuit based on the above idea and the motor drive control system based on this will be explained. The phenomenon shown in Figure 4 is the same even when the drive pulse width is shortened.
Figure 7 shows the situation. The drive shown in Fig. 7 has a narrow ffi dynamic pulse width compared to Fig. 4, so it can withstand only a small load, but the drive current waveform 23 at no load and the induced current waveform 23 after driving The relationship between the driving current waveform 24 at the limit load and the induced current waveform 24' after driving is the same as that shown in FIG. The load is detected by the method described above, but the configuration of the present invention normally moves the motor with narrow drive pulses assuming no load, and detects the load size from the induced voltage waveform after driving. When the load is small, the initial driving pulse width is narrow.

If the load increases and approaches the limit of @t< movement with a narrow drive pulse width, the next drive will pivot with a wide drive pulse width for a certain period of time, and then resume driving with the initial narrow drive pulse width. Return. The present invention generally has such a configuration, but
This will be explained in more detail with reference to the block diagram in FIG.

FIG. 8 is a block diagram showing the configuration of the present invention, and 25
26 is a circuit including an oscillation circuit, a frequency dividing circuit, etc., 27 is a pulse motor drive circuit, and 28 is a pulse motor.The configuration up to this point is the same as that of a conventional electronic wristwatch.

Reference numeral 29 denotes a load detection circuit which detects a load based on the induced current waveform after application of a drive pulse, as explained in FIGS. 4 and 7. 30 is a control circuit that controls the drive of the pulse motor 28 in accordance with the load state MK detected by the load detection circuit 29, and normally controls to supply a narrow drive pulse when there is no load and a wide pivot pulse when there is a load. do.

This control system will be explained with reference to Figure 9. FIG. 9 shows the state of the drive pulses, and these states are shown as pulses 31 and 32, which are supplied as described above in the section regarding the pulse motor. Pulses 31,32 are narrow pulse widths under no-load conditions. After applying pulses 31.52, the detection circuit of FIG. 8 detects and outputs the load condition, which is either no load or a small load condition. That is, since the load detection after pulse 31 was determined to be no load, the next pulse 32 has a narrow pulse width, and since the load detection after pulse 32 was also determined to be no load, the next pulse 33 also has a narrow pulse width. In load detection after pulse 33, it was determined that the vehicle was in a loaded state. In this case, after pulse 35, a second wave with a wider pulse width occurs several tens of m5ec later.
A recoil pulse 34 is applied with the same polarity (ie, same current direction) as pulse 33. For a fixed number of subsequent pulses, wide pulse width pulses 35, 36 are applied, and then again the initial narrow pulse width pulses 57, 58...
・is applied. To explain the relationship between the pulse 33 and the pulse 34, when a large load is detected by driving the pulse 33, the pulse 34 having a pulse width of 1c E l,- is applied after several tens of m5ec. Although it is determined that the load is large when the load is detected after the pulse 33, it is difficult to determine whether the rotor has operated at this time. This is because the induced current waveform in FIG. 7 shifts to the right and attenuates as the load increases. When the rotor does not operate, there is no induced voltage, but it is difficult to distinguish this from the situation where the rotor operates easily when the load is close to its limit. If the load increases gradually, the rotor will still be operating at pulse 33 at that time even if the load is determined to be large, and if the load suddenly becomes too large to be driven by a narrow pulse width, the rotor will not operate at pulse 33. It doesn't work. Distinguishing between the two is difficult. Therefore, it is easy to set the load detection after pulse application so that there is some margin.

In this configuration, pulse 34 is applied. When the rotor is actuated by the pulse 63, the pulse 34 is a pulse in the same direction as the pulse 33, so this pulse 34 becomes a pulse with an opposite phase, and the rotor does not rotate. Further, if the rotor is not activated by pulse 33, it is activated by pulse 34. At this time, the rotor is driven with a delay of several tens of m5ec (
However, this will not be visually recognized as an operation of the second hand (there is no need to worry about the unsightliness caused by this).Next, after detecting the load, a pulse 653 with a wide pulse width will be detected.
6 continues for a certain number of pulses is that the largest load on the rotor is the calendar 1P, and this continues for 3 to 4 hours, so if you immediately return to a narrow pulse width, the load state will change again. If one cycle is interrupted and this is repeated, two pulses will be supplied for each operation, increasing power consumption and eliminating the significance of reducing power consumption. Furthermore, the nine loads placed on the rotor are not only caused by the calendar mechanism, but also include one-off loads such as @ field, low temperature, and disturbance. In such a case, it is desirable that the number of continuous pulses with a wide pulse width be as small as possible. Considering this phenomenon, the number of continuous pulses should be several tens of seconds or more.
It is desirable to set it to several hundred seconds.

It is also possible to separately detect the load each time, determine whether the load is large or small, and set the pulse width each time, or other methods are also possible.The above is the configuration of the present invention, but the following A specific embodiment of the present invention will be described below. Fig. 10 is an example of a load detection circuit and a drive pulse control circuit of a timepiece according to the present invention. Reference numeral 25 in Fig. 10 indicates an oscillation circuit;
26 is a frequency dividing circuit, 28 motor and drive circuits, 2
This is a 9-piece motor load state detection circuit. The circuit elements will be sequentially explained below. The NAND GATE output of 39 is a clock for creating a narrow pulse when driving the motor in a no-load state, and generates a clock pulse delayed by 5 m5ec with respect to the falling edge of a 1 second signal, for example. At this time, the delay flip-frog 42 delays the input one-second signal by 5 m5ec and outputs it, and a narrow pulse with a width of 5 m5ec is generated at the output of the gate 46. The flip-flop 44 is a delay 7 flip-flop with a clock input of 128 Hz, and the output of the flip-flop 44 is delayed by 7.8 mθec relative to the input 1 second signal. Therefore, a 7.8 ma 130 width pulse is obtained at the output of the gate 47, and this is a wide pulse for driving when a load is applied.The gate 40 generates a pulse for discriminating between a no-load state and a loaded state with respect to the time until the minimum part of the voltage waveform generated by the rotor operation appears immediately after the application of the drive pulse. It is a clock for occurrence,
42. Judgment reference pulses are obtained at the outputs of 43 and 48 by the same operation as in 44.

! 10 FIG. 58 echoes the output narrow pulse of gate 46,
Reference numeral 59 corresponds to the judgment criteria pass and pass trap of the gate 48 output.

The gate 41 is arranged by a correction pulse generation circuit, and the pulse width is a wide pulse of 78 m5ec, and the generation position is delayed by, for example, 30 m5ec with respect to the pulse of the gate 46 or 47.

An example is shown in FIG. 1066. Gate 410 input terminal 5
7 is a correction signal which will be described later, and this correction signal is H-engine G1.
1[, a correction pulse is generated at the output of 41 and supplied to the subsequent stage. The input signals to the gates 39, 40, and 41 are signals for obtaining the above-mentioned pulses, and are appropriately combined with the outputs of the counter 26. 48.49 is a circuit that separates the above pulses to the driving inverter 14.15 and outputs them alternately every second. The gate 50 inputs one count input to the counter 52 when nine correction pulses are issued to the output terminal 41 while the counter 52 is at zero. After the counter 52 starts counting, the gate 50 continues until the output of the counter 52 returns to zero.
When 52 enters the counting state by the output of , the gate of 51 opens and continues to send a 2 second signal to 52 as a count signal until all outputs of 52 become zero.

As mentioned above, the counter 52 is set to run for several tens of seconds to several tens of minutes, and after detecting that the motor is in a loaded state, outputs a wide pulse drive signal for the above-mentioned time width. It becomes a timer for 47ri kakunta 52
Block 2? in Figure 10 outputs a wide pulse to the subsequent stage while block 52 is in the counting state. is an example of a circuit that detects a remoter load based on the operating state of the motor after application of a drive pulse. 5
5° 54 is a transmission gate which alternately selects the output of the drive impark 14, 15 in accordance with the movable signal. 53, 54 Deba? 'i are combined and input to the comparator circuit 55. Of the output signals of 53 and 54, the waveforms in the no-load state and the waveforms in the loaded state are shown in Figure 11.6.
0.61. In this case, the comparison circuit operates as a level detector, and the signal obtained by passing the comparison circuit output through an inverter becomes a rectangular wave shaped based on the set level. signal is obtained.

The gate 56 is a circuit that detects the falling position of the signals 62 and 64 after application of the driving pulse, and obtains 65.65 as an output signal. A state in which this falling position is included in the determination reference pulse 59 is determined to be a no-load state,
If it is not included in the pulse 59, it is determined to be a loaded state. 65 is clearly determined to be in a loaded state, and 57 is HIG.
It becomes H. As a result, for the case of waveform 61, a correction pulse 66 is subsequently applied, which completes the rotation of the rotor. However, as described above, this also includes the case where the rotation of the rotor is completed before 66 is applied.

The correction pulse 66 also passes through the gate 50 to the color/reference pulse 5
2, the gate 51 is turned on and 52 is counted tIVC. After that, the gate 47 is turned to O for a certain period of time.
Keep it in the N state and continue supplying the wide pulse drive signal. While the wide pulse is being supplied, the 57 ball is in the 0W state and no correction pulse is output. This is because the motor is considered to have sufficient output torque during wide pulse driving.

Figure 13 shows that after the motor rotation is detected by the detection circuit 29, the electric a1M
This figure shows the coil terminal output voltage waveform when the moving coil terminals are short-circuited. 90 in the figure corresponds to the drive current,
This corresponds to Figure 4, 20.21, etc.

Waveforms 91 and 92 are voltage waveforms induced at the coil terminal (9) in response to rotor vibration when the coil terminal is open.
1 is a small load state, and 92 is a case where the load has increased somewhat. 95 is a reverse induced voltage generated because the coil is opened after the drive pulse is applied.

The single-dot chain # in the figure indicates the input level set by the comparator circuit 55, and the point at which the induced voltage generated after application of the drive pulse exceeds this level is defined as the detection point. 93 and 94 are waveforms obtained by short-circuiting the coil terminals immediately after detection, and as a result, an induced voltage (therefore, a current is generated in the coil) due to rotor imaging, and the vibration energy of the rotor is absorbed by the coil. At the same time as a short circuit occurs, the vibration of the rotor is rapidly attenuated and stabilized.!For watches that have a second hand that moves in steps at Tf, the vibration of the second hand that occurs with each step can be a concern (and may even cause the second hand to malfunction). However, these problems can be solved by short-circuiting the coil terminals after detection as in the present invention (as shown in waveforms 93 and 94).

It has been confirmed that the load detection method of the present invention operates effectively even with respect to the magnetic field applied to the watch body, the number of cylinders, etc. FIG. 12 shows a detected current waveform when a DC magnetic field is applied in the direction of the coil of the pulse motor. 83 is a case where the directions of the magnetic field induced in the motor inner core by an external magnetic field and the driving magnetic field are opposite to each other, and 84 is a case where both magnetic fields are in the same direction.

In 83184, waveforms 85 and 86 have zero external magnetic field and can be considered to be almost the same waveforms. 87.88 is a waveform when the external magnetic field is 40 Gaugg. According to the waveform, the stronger the external magnetic field, the more difficult it is to operate in the direction 83.
It shows the same characteristics as the operation when the load becomes large. Therefore, the timepiece circuit of the present invention exhibits effective operation against the influence of external magnetic fields, and it has been experimentally confirmed that the strength against external magnetic fields is no different from that of conventional timepieces.

In the case of 87 in FIG. 12, since the minimum position of the waveform appears after the determination reference pulse, a correction signal 87' is added. Regarding impact resistance, it can be easily inferred from the above explanation that the present invention has an effective effect.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described here, and various improvements and modifications can be made.

[Brief explanation of the drawing]

FIG. 1 shows an example of a pulse motor for an electronic wristwatch according to the present invention. 2 and 3 show conventional circuit configurations, and FIG. 4 shows a current waveform of a pulse motor drive coil in a conventional timepiece. FIG. 5 is a diagram showing the relationship between the drive pulse width of the pulse motor, the output torque, and the power consumption. Figure 6 shows the correlation between the detected waveform and the rotor rotation phase. Figure 7 shows the coil current waveform when the motor is driven with a narrower pulse width than the conventional drive pulse. Figure 8 shows the clock according to the present invention. represents a circuit block. FIG. 9 is an example of a time chart of motor drive pulses by the circuit according to the present invention. FIG. 10 is a specific example of the block circuit shown in FIG. 9. FIG. 11 is an example of a time chart of the load detection section in FIG. 10. FIG. 12 shows changes in the coil current waveform when a DC magnetic field is applied to the electronic wristwatch according to the present invention. FIG. 13 is an example of a detected voltage waveform based on the control according to the present invention. 25... Oscillation circuit, 26... Branch circuit, 27...
...Drive circuit, 28...Motor, 29...Motor load detection 4! IJ constant circuit, 30...control circuit,
31-33... Narrow pulse drive signal, 34...
- Correction signal, 55... wide pulse drive signal, 59...
... Load judgment base pulse, 6o... No-load detection signal, 61... Load detection signal. Above glass 4 pieces / A / 4- 4) 1 figure stem 3 figures Z + 1 area 爲田 (endless 61 pieces ↓ I (Puko)

Claims (1)

[Scope of Claims] 1. A clock circuit including a crystal oscillator, a pulse motor including an electromagnetic drive coil, a pulse motor drive circuit, and a circuit for detecting the rotational operation of the pulse motor, and the detection circuit is configured as described above. After applying a drive pulse to the motor, the electromagnetic drive coil is put into an open loop state, and the induced voltage obtained between the coil terminals is used as a detection input signal, and the drive conditions of the motor are controlled according to the output of the detection circuit. Electronic clock. 2. The electronic timepiece according to claim 1, wherein the electromagnetic drive coil is short-circuited to attenuate the rotation of the rotor when a suitable detection signal is obtained in the detection circuit.