JPS61274290A - Electronic timepiece - Google Patents

Abstract

PURPOSE:To enable extremely accurate detection of a load to be performed, by detecting an induced current in a coil after the end of applying a pulse by a load detection means. CONSTITUTION:A load detection circuit 29 detects a load by the waveform of an induced current after the application of a drive pulse. A control circuit 30 is provided to control the driving of a pulse motor 28 according to the state of the load detected by the load detection circuit 29 in such a manner that normally, a narrow drive pulse is fed with no lead while a wide drive pulse done with a load. Thus, the driving system of a conversion mechanism can be driven by a small power when a load in small while being done by a large power when it is large thereby reducing the power consumption significantly with the conversion mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slave clock, and relates to an electromechanical transducer mechanism thereof. The purpose of the present invention is to reduce the power consumption of the converting mechanism and also to improve reliability.

Since the so-called quartz wristwatch with a full-time standard oscillator was put into practical use, its high precision and high reliability led to its widespread use.During the 7t-t period, the technological innovation of this quartz wristwatch has been remarkable. The power consumption of −f: was also initially 20
Things that used to require a few μW can now be realized in the light of about 5 μW – however, the current power consumption is 5 μW.
Looking at the complete breakdown of μW, the crystal resonator's oscillation frequency divided by 1 is 1.5 to 2 μW, and the electromechanical conversion mechanism is 3 to 5 μW, with a noticeable cyan balance, that is, the consumption of the electromechanical conversion mechanism. Since the power consumption accounts for 60 to 70% of the total power consumption, reducing the power consumption of this electromechanical conversion and mechanism is likely to be effective in further reducing the power consumption in the future. The current situation is 1! The conversion efficiency of the air-mechanical conversion mechanism is quite high, and it is quite difficult to increase the efficiency further. However, conventional electromechanical conversion mechanisms are designed to be sufficiently effective even in the worst-case scenario due to requirements such as load-resistant mechanisms such as calendar mechanisms, resistance to environments such as temperature and air, and resistance to external disturbances such as vibrations and shocks. It's here.

For this reason, the conversion mechanism was required to have the ability to withstand a certain load under certain driving conditions, but in reality, the watch body is only under such a load for about 4 to 5 hours in a day. Most of the 20 hours are in a no-load state. In other words, if one clock body is always in a no-load state, is one exchanger m designed to withstand such a large load? There is no need to do this, and in the case of ;f:, the power consumption can be reduced considerably, but one clock is a short time but creates a cold environment, so in order to guarantee this, full power is supplied and a large output is required. It was necessary to use a conversion mechanism to obtain .

The present invention corrects the above-mentioned irrationality by driving the conversion mechanism with a small amount of power when the load is small and with a large amount of power when the load is large. This is a significant reduction. Moreover, such a drive system is constructed using reliable all-electronic means without including mechanical contacts, and achieves stable interlocking that can cope with variations due to the type of conversion mechanism and mass production.

The present invention will be explained below. First, a step motor and its operation will be explained as an example of an electromechanical conversion mechanism used in an electronic watch, and a detailed explanation of the present invention will be explained based on this step motor. Then, a detailed explanation will be given of examples. do.

Figure 1 shows an example of a conventionally used electronic wristwatch motor.
stators 2.5 are arranged facing each other with the rotor 1 in between, and these stators 2 and 3 are each connected to a yoke 5 wound around a coil 4 to form a set of stators. Il! has been completed.

The arcuate portions 2a and 3a of the stator 2.3 are completely eccentric with respect to the center of the rotor 1 so that the stator 2.5d and the rotor 1 can rotate in a fixed direction.
(S) Position All stators 2.5 ((shifted). This type of step motor has been in practical use for some time and was driven by a circuit block as shown in Figure 2.

Reference numeral 10 denotes a crystal resonator, which is driven by a two-wavelength oscillation circuit 11.

The frequency is divided by a frequency divider 12 with a constraint number a of
3, two pulses having an appropriate time width and a 180° phase difference are generated at an appropriate time interval.

As an example, a pulse of 7.8 m5ec per 2' will be considered and explained below. C this pulse! M
The signal is input to a driver 14.15 composed of an O8 inverter, and its output is supplied to terminals 4a and 4b of the coil 4. FIG. 3 is a detailed diagram of a part of this driver, in which a total of 18 signals f:
When D is applied, a current flows as shown by an arrow 19, and conversely, when all the same signals are applied to the input terminal +-17 of the other inverter 15, 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 the coil 4 can be alternately reversed. Specifically, the current flowing through the coil 4 can be alternately reversed every second.
A current of 8 msec can be passed through the coil 4. The stator 2.3 of the step motor shown in Figure 1, which is constructed in this intricate drive circuit, has an N pole.

S poles occur alternately and are repelled by the 8 poles of rotor 1.

The rotor 1i can be rotated by 1130° by suction. The rotation of the rotor 1 is transmitted to the fourth wheel 7 through the intermediate wheel 6, and further to the third wheel 8 to second wheel 9, and further to the cylinder pinion, hour wheel, and calendar mechanism (not shown). Operates an indicating mechanism consisting of a minute hand, a second hand, a calendar, etc.

The first pulse motor operates in principle as explained above, and can be used as a conversion mechanism for electronic wristwatches.

In the drive circuit shown in FIG. 3, when a high level signal is applied to the terminal 17 and a signal 18 is applied to all terminals 16, as shown by the arrow 19 (current flows through the MOS transistor 15, the driving current is A voltage drop occurs and a signal waveform corresponding to this current can be detected at terminal 4b.The current waveform is 1, for example, as shown in Fig. 4. In Fig. 4, section A is the drive section and in this case 7.amSa:
, the current flowing in this section A is the current consumed by driving the motor. The reason why the current waveform at point A has a complicated shape as shown in the figure is that in addition to the current generated based on the t' section pressure applied by the drive circuit, the coil is also affected by the rotation of the driven rotor. This is a friend in which induced currents are superimposed.

Section B is the section after the drive pulse is applied, and the rotor rotates due to inertia and vibrates until it stops at a stable position.At this time, this section is the section where the rotor rotates due to inertia and vibrates until it stops at a stable position.
Since the P-channel MO8) range nut is ON, an induced current flows to the coil 4 in response to the movement of the rotor in the loop between the coil 4 and this transistor. $
This is why the waveform in section B in Figure 4 is pulsating. Therefore, the shapes of the driving current waveform and the induced current waveform after driving can be correlated with the rotational position of the rotor.

Now, waveform 20 and waveform 20' in FIG. 4 are a series of waveforms, and this is 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 thick and close to the rotor's operating limit, and waveform 21 and waveform 21' are when the load exceeds the maximum allowable load. This is the case.

If you carefully 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 rotation of the rotor slows down as the load increases.

The rotor imaging frequency is low until it stops at a stable position.
Moreover, it has been experimentally confirmed that the amplitude becomes smaller. Considering this phenomenon in reverse, if the load on one rotor is always in a no-load state, the tK dynamic pulse width is 18 mFJ! It is understood that driving can be performed with a shorter pulse width than c. In fact, even if the pulse width is shortened, the motor will still operate and the output torque will decrease.

This situation is shown in FIG. FIG. 5 shows the output torque characteristic T and the power consumption characteristic T when the drive pulse is completely changed. The aforementioned drive pulse @7.8m5ec
corresponds to P in this figure. That is, the output torque is T with a pulse width Pt? , and the power consumption is 2. This output torque T? As mentioned above, is set so as to be able to sufficiently withstand the load encountered by the watch body. However, the cuff Dλ on the rotor
If the load is small or negligible, the output torque will be small and the drive pulse width will be short, and therefore the power consumption can be reduced. For example, if you drive with the pulse width of PL, the output torque TI The present invention took this point into consideration and detects the entire load on the rotor, thereby driving the rotor with a narrow pulse width when there is no load or when the load is small.

This is a device that applies a large load and then tries to drive it with a wide pulse width the next time, so it is a rational and low power attempt. As mentioned earlier, the overwhelming majority of people are in a no-load state, so the effect of reducing power consumption is extremely large. For example, as shown in Figure 5, when there is no load (20 hours), the pulse width of Pl is the same as when loaded (4 hours).
time) is driven with a pulse width of P2, and assuming that 2='A, the average power consumption is 2. It is driven with a pulse width of P2 at all times, and 9. compared to the conventional method, the power consumption is less than 60 yen. This results in a significant reduction in power consumption.

By the way, it was briefly stated above that one load was detected...'', but 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. Looking at the current waveform flowing through the coil in Fig. 4, it can be seen that this current waveform changes as t'M increases. is shifting towards

By focusing on this point, the load size t can be determined,
The amount of change in this waveform is extremely small, making it difficult to absorb variations in mass production.Also, it is extremely delicate control. Must be.

Therefore, the present invention focused on section B after application of the drive pulse. Also in this section B, as the load increases, there is a shift to the right, for example, to the point where the minimum fit is first achieved. Moreover, compared to the waveform change t'' in section A.

A change several times larger can be obtained. Therefore, detecting the magnitude of the load by modifying the induced creeping current waveform in this section B is as follows:
Compared to the above section A, it is easier and has higher reliability (fx).This phenomenon is the same when the driving pulse width is shortened and the 6th section
The situation is shown in the figure. The drive shown in Fig. 6 has a narrower drive pulse width than the one in Fig. 4 and can only withstand small loads; The relationship between ', the drive current waveform 24 at the operating limit load, and the induced current waveform 24' after ffi operation are the same as shown in Fig. 4.The load is detected by the method described above, but the uninvented method The configuration is usually considered when the motor is under no load, and the magnitude of the load is always detected by the induced current waveform after driving.

When the load is small, the beginning is narrow! Continue driving at IA dynamic PARNU width. When the load increases and the driving force approaches the limit of driving with a narrow driving pulse width.

From the next drive, it pivots with a wide drive pulse width for a certain period of time.

After 7, the drive is returned to the original narrow drive pulse width. Although the present invention generally has such a structure, a more detailed explanation will be given with reference to the block diagram of FIG.

FIG. 7 is a block diagram showing the entire configuration of the present invention.
26 is a time standard oscillator, 26 is a circuit including a frequency dividing circuit, 2 and 7 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. 29 is a load detection circuit, which will be explained in FIGS. 4 and 6, and 30 is a control circuit that detects all loads in the induced current waveform after application of a drive pulse. A circuit that controls the ffi operation of the pulse motor 28 according to the 1 normally controls to supply a narrow drive pulse when there is no load and a wide drive pulse when there is a load.

This control method will be explained with reference to FIG. FIG. 8 shows the state of the driving pulses, and the pulses 31 and 32 are shown as pulses 31 and 32 in this state, which are supplied in the same manner as described in the previous section regarding the pulse motor. The bus s, x51°32 is a narrow pulse width in the no-load condition. After applying pulses 31, 32, the detection circuit of FIG. 7 detects a load condition, which is either no load or a small load condition. That is, since the load detection after the pulse 31 is determined to be no load, the primary pulse 32 has a narrow pulse width.

The load detection after pulse 32 also determines that there is no load, so the next pulse 33 also has a narrow pulse width. Then, when the load is detected after pulse 55, it is determined that there is a load.90 In this case, after pulse 53, it is several tens of meters! After JC, a second drive pulse 34 with a wide pulse width is applied with the same polarity (i.e. the same current direction) as the pulse 33 □For a fixed number of pulses thereafter, a pulse 55,56 with a wide pulse width is applied; The initial narrow pulse width pulse 57, 58... is applied again.The relationship between pulse 53 and pulse 34'lt To explain, when a large load is detected in sxb of pulse 35, a wide pulse is applied after a few minutes. A pulse 34 with a pulse width of 0 is applied. This means that the load is detected after pulse 33 and it is determined that the load is heavy, but at this time the rotor operates and it is difficult to determine whether t is reached or not. This is due to the induction in Figure 6. The current waveform shifts to the right and attenuates as the load increases. When the rotor does not operate, no -4 electromotive current is generated, but it is difficult to distinguish this from the situation where the rotor barely operates when the load is close to its limit. If the load increases gradually, even if it is determined that the load is large, the pulse 55 at that time will be used (the σ rotor is still operating, and if the load suddenly becomes large enough that it cannot be driven with a narrow pulse width, the pulse 33 will be used). Rotor does not work.

It is difficult to distinguish between the two. Therefore, in the zero-pulse configuration, in which it is easy to set the load detection with a little more margin after pulse application, all 54 pulses are applied. When the rotor is operated by the pulse 33, the pulse 54 is defined as a pulse in the same direction as the pulse 35, and this pulse 34 is a pulse in the opposite phase, and the rotor does not rotate. or,
The rotor is actuated by the pulse 33, and when the rotor is turned off, the rotor is driven by the pulse 34. At this time, the rotor will be driven with a delay of several tens of meters, but this will not be visually recognized as the operation of the second hand - there is no need to worry about the unsightliness caused by this. Next, to detect the load, we chose a configuration in which pulses with a wide pulse width (35.36t) continue for a constant number of pulses.The reason is that the largest load on the rotor is the calendar mechanism, which is Since it lasts for ~4 hours, if you immediately return to a narrow pulse width, it will be judged as a temporary load condition, and if this is repeated, two pulses will be supplied for each operation, which will increase power consumption and defeat the purpose of reducing power consumption. (Also, the load on the rotor is not only due to the calendar mechanism, but also single loads such as magnetic fields, low temperatures, disturbances, etc.) In such cases, the number of continuous pulses with a wide pulse width should be as small as possible. Considering the phenomenon of desirable mouth,
It is desirable to set the number of continuous pulses to several tens of seconds to several tens of minutes. More than.

Regarding the structure of the present invention, first, a concrete example of the present invention will be explained. FIG. 9 shows an example of a load detection circuit and a drive pulse control circuit of a timepiece according to the present invention.

In Fig. 9, 25 is a rooting circuit, 26 is a frequency dividing circuit, and 28
29 is a motor and drive circuit, 29 is a motor load state detection circuit, and 50 is a control circuit, which correspond to the configuration shown in FIG. Below, each circuit element will be explained one by one (,,!
i9's IIIND GATI! :The output is a clock to create narrow pulses when driving the motor in no-load condition, and I? For AJ, 5m for a 1 second signal fall.
Generates 9 clock pulses delayed by 5 ec. At this time, the delay flip-flop 42 outputs a one-second signal f5mmc.
The output will be delayed, and the output of gate 46 will require 5m5.
A narrow pulse of aclti occurs.

The flip-flop 44 and the BAND gate 47 are circuits that generate wide pulses when driving the motor in a loaded state. The pulse width at this time is fJ, t = 7.8 m5ec. 128 to the clock input terminal of the flip-flop
A pulse of LIm is being supplied.

The 1 second signal supplied to the input terminal of the flip-flop is 1
The signal is output with a delay of Z8 mSeC based on the clock of 2811z, and a wide pulse with a width of 7.8 m5ec is generated at gate 47, which operates in the same manner as gate 46.

The fc element and flip-flop 4 are surrounded by the frame 110 above.
2. 41NA14D gates 39, 47, 46, etc. are constructed to constitute a pulse generation circuit - NARD gate 4
Reference numeral 7 denotes a gate that passes the narrow pulse and the wide pulse into a signal from a counter 52, which will be described later. Gate 4 [1,48
A flip-flop 43 is a circuit that generates a reference pulse for load determination to determine whether the motor is in a no-load state or a loaded state.

A flip-flop 43 which uses the output pulse of the gate 40 as a clock signal and a 1 second signal are used to output the output pulse of the gate 46 or 4.
Under the same operation as 7, the load judgment reference pulse is applied to gate 4.
The output of 8 is obtained.

The reference pulse of the output of the gate 48 is used to determine the load detection signal of the gate 56, which will be described later.

FIG. 10 shows the correlation between the output signals of each gate related to load detection. The operation of FIG. 9 will be explained below together with FIG. 10.

FIG. 10 58 corresponds to the output narrow pulse of gate 46,
59 corresponds to the judgment reference pulse of the gate 48 output. The gate 41 is a correction pulse generation circuit, which generates a wide pulse with a pulse width of 7.8 msec, and the generation position is the gate 4.
For example, there is a delay of 50 m5ec for 6 or 47 pulses. An example is shown in FIG. 1066. The input terminal 57 of the gate 41 outputs a correction signal, which will be described later.
A correction pulse is generated at the output of 41 only when the GH is used, and is supplied to the subsequent stage. The input signals of 59, 40, and 41 are signals for obtaining the above-mentioned pulses, and all the outputs of the counter 26 are appropriately combined. 89.49 is a circuit that separates the pulses from the inverter 14.15 for all 11 Ath pulses and outputs them alternately every second.

The gate 50 controls the counter 5 when a correction pulse is issued to the output terminal 41 while the calendar 52 is at zero.
2, the quant input is input one time. When the calendar 52 starts its cycle, the gate 50 remains in the OFF state until all outputs of the calendar 52 return to zero. gate 5
When 52 enters the count state by the output of 0, 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 appropriately set between several tens of seconds and 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 will be an evening 1 timer to continue.

47, the output of the counter 52 is used as a gate input, and while the counter 52 is in the counting state, a wide pulse is output to the subsequent stage. Block 29 in FIG. 9 is an example of a circuit that detects the motor load based on the operating state of the motor after application of the drive pulse.

Is 55.54 the transmission gate or the drive inverter? 4.15 outputs are mutually selected according to the drive signal.

The outputs of 55 and 54 are combined and input to a differential amplifier 55 via a capacitor. Of the 55.54 deba signals,
The waveforms in the no-load state and the waveforms in the loaded state are shown as 10th waveforms, respectively.
Shown in Figure 60.61. Note that there is no load on the output signal 60, and the induced current 20' in FIG. 4 and the induced waveform 25 in FIG.
′.

Dekai S No. 61 is under heavy load, and among the induced current waveforms shown in FIGS. 4 and 6, the induced current waveforms 22' and 2 at the operating limit are
This corresponds to a waveform near 4'. Of course, the criteria for determining the load state can be set arbitrarily by the designer. The induced first-flow branch shape 60.61 has a peak position (
It is converted into a differential signal whose sign is inverted at the transition point). The voltage signal is passed through an inverter 55 to generate signals 62 and 6.
I got 4. Therefore, the signal 62 becomes a rectangular wave that inverts at the peak position of the induced current waveform 60, and the signal 64 becomes a rectangular wave that inverts at the peak position of the induced current waveform 61.

In addition, the peak position and reverse position! For complete clarity, the peak positions of the induced current waveforms 60 and 61 are marked with the signs a - f, and correspondingly, the inversion positions of the signals 62 and 64 are marked with a' ~
They are marked e', a", b", f".

The output of the inverter is delayed by an OR time constant circuit so that it becomes one input of the Nant gate 56, and the intermediate output of the two inverters is made the other input of the Nant gate 56. We obtain signals 65 and 65 in the figure. Signal 651-4 corresponds to output waveform 60, and signal 65 corresponds to output waveform 61. Output waveform 60.61 and signal 65.
65f, it is clear that the pulse of signal 62.65 indicates a predetermined peak position kt- of the output waveform. The load state is detected by determining whether the pulse position of this signal 65.65 is inside or outside the above-mentioned judgment reference pulse 59, and the former case is determined to be a no-load state, and the latter case is determined to be a loaded state. do. Therefore, signal 65 indicates a no-load condition, and signal 65 indicates a loaded condition. It should be noted that the blade signals 66 and 65 of the Nant gate output pulses in the negative direction.

Next, we will discuss the correction pulse generation means.

Gate 104 [load detection signal which is the output of gate 56 and judgment reference pulse IB@sq which is the output of gate 48,
and a signal delayed by 1 second signal k18 rnsec, which is the trigger of the delay flip-flop 44, are input. The output signal of the delay 7 limp 70 amplifier 44 acts as a mask signal for determining the detectable period in the gate 104. With the above configuration, the detection signal when there is no load (65 in FIG. 10) passes through the gate 104, but the detection signal 65 when there is no load is prohibited. Line 57tfi is the output of the clip flop formed by gates 107 and 108, with the sescent input formed by gates 106 and 105. The 1 second signal input to the gate 106 is 7
This is to determine the desired cent state of the link float, and the output 57 is always set to H in the load detection state. In this state, the signal that detects the no-load state is sent to the gate 104.
When it passes through, it passes through the gate MO5, +06i, resets the 7 lip flop, and puts the output 57 in the L state. However, when the load is heavy, the reset signal is not input, so the output 57 remains at H level. When the output 57 reaches the H level, the correction pulse is passed through the correction pulse generating gate 41, so that the correction pulse is supplied to the coil through the drive circuit gate 48 or 49. Note that the other input of the gate 105 receives a signal that prohibits passage of the detection signal at the same time that the counter 52 starts operating. Further, the mandatory signal of the gate 104 is replaced by a signal that inhibits the detection signal while the drive current is applied to the coil, and is output from the flip-flop 44. Therefore gate 1
By inputting the output of the gate 48 and the output of the flip-flop 44, the circuit 04 becomes a determination circuit that determines a light load state when the load detection signal from the gate 56 is generated within a predetermined time.

As a result, for the case of waveform 61, the correction pulse 66
is continuously applied, and the rotation of the rotor is completed by 66Vc. 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 capacitor 52.
It is input to 51 goo) io'N state, 52 total count state, I lesson. After that, goo for a certain period of time) 47 total O
Keep N state and wide pulse! jA Continue to supply the auxiliary signal. While the wide pulse is being supplied for 4$c, 57 is in the LOW state and no correction pulse is output. This is because the motor is considered to have sufficient output torque during wide pulse driving.

As the peak detection circuit, various systems can be considered in addition to the 55 differential amplifier circuit. FIG. 18 is a pronk diagram of a peak detection circuit using a delay circuit. In the figure, 55.54 Fi transmission gate, 80 is a general amplifier in place of 55 in FIG. 9, 81 is a delay circuit, and 82 is an 80 This is a comparator that inputs the outputs of 81 and 81. An example of the amplifier 80 is shown in the thirteenth
or FIG. 14. The motor drive detection waveform 25°24, etc. mentioned above is a waveform of several meters that substantially occurs near the power supply level.
Since the signal is approximately V to several tom7, it is divided by resistors 66 and 67 and converted to the input operating level of the amplifier. A waveform shown in FIG. 16 76 appears at the terminal 68. FIG. 14 shows a circuit improved from FIG. 15, in which an MQS transistor is inserted in place of the resistor 67, and a return circuit is used to control the channel impedance of the transistor 690 so that the amplifier input level becomes the operating level. Motsu, block 70
is a circuit that detects the output level. FIG. 15 shows a simple embodiment of the delay circuit 81, where 71.75 is a transmission gate and 72.74 is a load capacitor. In this case, the input signal 76 at terminal 68 is delayed as 77 at the output terminal.

FIG. 17 schematically represents this waveform. Input signal 76 is transmitted to capacitor 72 by transmission gate 71, and the terminal voltage waveform of 72 becomes 79. Further, a waveform 77 appears at the output terminal 75 by the transmission gate 73. Comparator 82 outputs a rectangular signal shown at 78 when waveforms 76 and 77 are input.

As the delay circuit, the one shown in FIG. 15 is suitable, but since the input signal frequency is relatively low, a Bakken relay type data transfer element or the like is also suitable.

It has been confirmed that the load detection method of the present invention operates effectively even in the case of magnetic fields or shocks applied to the watch body. FIG. 19 shows the detected current waveform when a DC magnetic field is applied in the direction of the coil of the pulse motor. 85 is a case where the directions of the magnetic field induced in the core in the motor by an external magnetic field and the driving magnetic field are opposite to each other, and pl 84 is a case where both magnetic fields are in the same direction.

At 85.84-, waveform 85.86 has an external magnetic field of zero, and can be considered to be almost the same waveform. 87.88 is the waveform when the external magnetic field is 400auss.

According to the waveform, the operation in the direction 85 becomes more difficult as the external magnetic field becomes stronger, and exhibits the same characteristics as the operation when the load is very strong. Therefore, the timepiece circuit according to the present invention operates effectively 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. 19, since the minimum position of the waveform appears after the determination reference pulse, a correction signal 87' is added. From the above explanation, it can be easily inferred that the present invention has an effective effect on impact resistance as well.

Figure 11+7) Pulse motor, rotor to.

is made of permanent magnets, and the stator 101 is an integral type with no gaps, unlike the one shown in Fig. Nonchi 102. +
03 has been formed.

104 is a drive coil. Since such a pulse motor is connected to the stator 101, the induced current after driving is as shown in FIG. 12 and as shown in FIG.

It is slightly different from Fig. 6. However, waveform 105 at no load
．． 105', waveforms 106 and 1m6' under load are basically the same, and it will be understood that they can be realized using the same method. When a one-piece stator is used, the gap between the rotor and the stator is always kept constant, so a stable induced current can be obtained with good mass productivity.

As described above, according to the configuration of the present invention, the load detection circuit that detects all the induced current generated in the coil is connected to the end of the coil, and the load detection section W! & is configured to detect the induced current generated in the coil after the pulse signal is applied,
In addition, the load detection circuit outputs a load detection signal in accordance with the induced current of a predetermined value, and has a determination screen 2r for determining a light load state only when load detection No. 1g occurs within a predetermined time. , has the following effects.

a) Induction 1 before the present invention! The method of detecting current as a load detects, when a drive pulse is applied to the coil, a change in the current value of the drive pulse due to an induced voltage in the opposite direction to the drive pulse. However, when the rotor is forcibly driven by the drive current, there is no sufficient difference in the induced current value between light load and heavy load, making it impossible to perform reliable and stable load detection. It contained. The present invention focuses on the fact that the induced current value when the rotor rotates by a predetermined angle after the end of pulse application and is undergoing damped oscillation is not affected by the supply voltage value and there is a large difference between light load and heavy load. By using the load detection means to detect the induced current generated in the coil after the pulse application is completed, it is possible to detect the load with extremely high accuracy.

b) The load detection circuit of the present invention detects the induced current generated in the coil after application of a drive current as a load, and detects a light load state when the detection signal is generated within a predetermined time. Since the deviation in the peak position of the induced current caused by damped vibration changes greatly depending on the load, detection accuracy is improved. It has merits.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a pulse motor of a conventional electronic wristwatch. The WJz diagram and FIG. 5 are diagrams showing a conventional circuit configuration, and FIG. 4 is a diagram showing a current waveform of a pulse motor drive coil in a conventional timepiece. FIG. 5 is a diagram showing the relationship between output torque and power consumption with respect to the drive pulse width of the pulse motor. Figure 8 is a coil current waveform diagram when the motor is fully driven with a pulse width narrower than the conventional drive pulse. FIG. 7 is a diagram showing a circuit plotter of a timepiece according to the present invention. FIG. 8 is a diagram showing a time chart of motor drive pulses by the circuit according to the present invention. FIG. 9 is a diagram showing a specific example of the block circuit of FIG. 8. FIG. 10 is a diagram showing an example of a time chart of the load detection section in FIG. 9. FIG. 11 is a diagram showing an example of a pulse motor for an electronic wristwatch according to the present invention. FIG. 12 is a coil current waveform diagram during narrow pulse driving in the pulse motor of FIG. 11. 15 to 18 are diagrams showing other examples of the load detection section in FIG. 9. FIG. 19 is a diagram showing changes in the coil current waveform when a DC magnetic field is applied to the electronic wristwatch according to the present invention. 25... Oscillation circuit, 26... Frequency division circuit, 2
7... Drive @ road, 28... Motor, 29
...Motor load detection judgment circuit, 50...Control circuit, 51-3!1...Narrow pulse drive signal, 54
...Correction signal, 55...Wide pulse drive signal, 5
9... Load judgment reference pulse, 60... No-load detection signal, 61... Load detection signal. Figure 1 Figure 2 Figure 3 Figure 4! Figure S Figure 3 Figure 1 O Figure 7 Figure 1 / Figure 72 Figure 1 Z Figure - Continued Correction 1! ! ' (Method) 1.・Indication of B 1985 Patent Application No. 299485 2 Masterpiece electronic watch of invention 4 Agent 5 Appropriate order 1'Y Procedural amendment: 1iiF (Method) 1. Page 29 of the specification, line 6 from the bottom to The 5th line says, ``Figure 8 is a conventional coil undercurrent waveform diagram.'' and ``@Figure 6 is a coil current waveform diagram when the motor is driven with a narrower pulse width than the conventional drive pulse.'' JIC Okemasa amendment. Above agent Mogami Mu・', 54..゛21.-2

Claims (1)

[Claims] an oscillator circuit, a frequency divider circuit that frequency divides the output signal of the oscillation circuit, a drive circuit operated by the output signal of the frequency divider circuit, a step motor comprising a permanent magnet rotor, a stator, and a coil and driven by the drive circuit; In the electronic timepiece having a wheel train driven by the step motor, an induced current connected to the end of the coil and generated in the coil after application of a drive current is detected as a load, and when the induced current reaches a predetermined value, a load is detected. It has a load detection circuit that outputs a detection signal, and a control circuit that is connected between the frequency dividing circuit and the drive circuit and is controlled by the output of the load detection circuit, and the control circuit outputs a pulse drive signal for normal hand operation. and a correction pulse generation circuit that outputs a correction pulse having the same polarity as the pulse drive signal and a pulse width larger than the pulse drive signal when the load detection circuit detects a heavy load. . An electronic timepiece, characterized in that the load detection circuit includes a determination circuit that determines that the load is light when a load detection signal is output within a predetermined period after application of the drive current.