JPS6056080B2 - Drive timing detection control device for step motor for watches - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electronic wristwatch step motor having a bipolar rotor, an integrated stator, and a coil. The present invention relates to a drive timing detection and control device for a timepiece step motor that is effectively used to drive steps.

FIG. 1 shows a conventionally used two-pole step motor for electronic wristwatches, which is also used in the present invention.

FIG. 2 is a timing chart of conventional drive pulses used to drive a step motor having this structure.

In FIG. 2, signals a and b are drive signals for normal operation, signals c and d are drive signals for BLD operation, signals e and f are drive signals for forward fast forwarding, and signals g and er are drive signals for fast forward reverse rotation, respectively. In the case of a step motor that is driven step by step every second with the drive pulses shown in Figure 2 a and b, there is a surplus of drive energy after driving one step, and the rotor 3 in Figure 1 has damped vibration until it comes to rest. consumed as.

This damped vibration ends in about 100 mSec and does not affect the next step drive after 1 second.

However, when a continuous drive circuit of the step motor is required, such as during two-step continuous drive when the BLD (battery life warning device) is activated, and during forward and reverse fast forwarding for electronic needle correction, the interval between each step drive is short. shellfish. Therefore, since the next drive pulse is applied before the damped vibration of the rotor 3 ends immediately after the one-step drive, there is an influence on the next step of the damped vibration. The manner of this influence differs depending on the phase of the damped vibration when the next drive pulse is applied.
If the next drive pulse is applied to the phase in which the rotor 3 is moving in the forward rotation direction due to damped vibration in normal rotation drive, the energy of the damped vibration is added to the next drive energy,
Furthermore, if the rotor 3 is applied in a phase in which it is moving in the reverse direction, the next drive energy will be transferred by the energy of the damped vibration. In the former case, the rotor 3 rotates too vigorously, causing phenomena such as skipping two seconds, resulting in instability; in the latter case, a phenomenon such as the rotor 3 not rotating due to insufficient driving energy occurs. In the case of conventional continuous drive of a step motor, the interval between each drive pulse is widened, and the next drive pulse is applied when the amplitude of the damped vibration of the rotor 3 becomes sufficiently small, so that the step motor is driven as described above. The effect of damped vibration was reduced. Although I am calm,
As a result, there were drawbacks such as a longer time required for needle correction. Furthermore, if the next drive is performed after the damped vibration energy of the rotor 3 has become sufficiently small, most of the remaining drive energy is consumed by the damped vibration of the rotor 3, resulting in a waste of drive current consumption. The present invention eliminates such drawbacks by applying the next drive pulse at a timing when the energy of the damped vibration of the rotor 3 immediately after driving one step can be effectively utilized when the step motor is made to rotate continuously. , the purpose is to save driving current consumption and increase the speed of continuous rapid forward movement of the pointer.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

First, let us consider the process in which the rotation angle θ of the rotor 3 shown in FIG. 1 changes from O to π due to normal rotation drive. Figure 3A is this 1
The movement of the rotor 3 during step drive is shown. Figure 3B is
FIG. 1 shows the waveform of the current flowing through the coil 2 at that time. O<
During t<t1, the drive pulse is being applied, and the current corresponds to the drive current. Also, when t>chi, the current is almost at the rotor 3
This is a reverse induced current that is caused only by the motion of the Looking at the motion of the rotor 3 when t>t1 in FIG. 3A, it can be seen that it is undergoing damped vibration. Here, the direction of motion of the rotor 3 due to the damped vibration is the forward rotation direction, and the timings of maximum rapid motion are 8 and 9 in FIG. 3.

At this time, the reverse induced current value reaches its peak value. If this reverse induced current can be detected in some way, the energy of the damped vibration can be utilized by applying the next drive pulse almost immediately thereafter. In the case of continuous fast forwarding, this detection and control is performed for each step drive. Next, a drive timing detection control method will be explained according to a specific timing chart.

FIG. 4 is a timing chart of drive timing detection control during BLD operation.

FIG. 4 1 shows. This is the first drive signal of two-step continuous drive, and applies a voltage to the terminal 01 side of the coil 2 in FIG. FIG. 4k shows a voltage waveform obtained by chopper-amplifying the current waveform at this time only in the direction in which the damped vibration energy can be effectively used for the next drive. Here, the chopper amplification means to amplify the current flowing through the coil 3 as a voltage by alternately switching a closed circuit of a low impedance element and coil 3 and a closed circuit of a high impedance element and coil 3. Tell me the method. A specific method of increasing the chopper width will be described later in the description of the drive circuit. This chopper amplification voltage is detected by a comparator 6, and then the next drive pulse is applied to the terminal 02 side of the coil 3 after a delay of 1''7 nsec by adjusting the optimal drive timing.Here, the detection period is the drive pulse 2007TLse from the end of application
Up to c. This detection period is a period in which the signal indicated by the dotted line in FIG. 4k is Hi. In addition, the next drive pulse is the one at the evening timing shown in Fig. 4. By performing the above detection control every other step, that is, at intervals of 2 seconds, the damped vibration energy is used for the next drive without wasting it. It is possible to shorten the width of the next drive pulse output after the pair of two steps.

In other words, the required driving pulse width of the I signal in FIG. 4 is calculated from e to Δe.
can be reduced only by These allow the drive current consumption during BLD operation to be saved. If the damped vibration of the rotor 3 becomes small due to a sudden factor and becomes undetectable, the next drive pulse will not be applied, so the 3007ns
Control is such that the next drive pulse is forcibly applied after ec. The detection control process during forward rotation and fast forwarding for needle correction is basically the same as the process during BLD operation described above, but both the drive pulse is applied to the terminal 01 side of the coil 3 and the drive pulse is applied to the 02 side. The difference is that detection control is performed more than repeatedly.

A timing chart in this case is shown in FIG. 5m is a start pulse signal for normal rotation fast forwarding, FIG. 5m is a current waveform at that time, and FIG. 50 is a voltage waveform obtained by chopper-amplifying the current waveform. This chopper amplification voltage is detected within the period in which the signal shown by the dotted line in Fig. 50 is Hi, and after a delay of d″M, sec, the next driving pulse that is applied is shown in Fig. 5p, and is applied as necessary. Emse drive pulse width
c can be reduced by ΔEmsec. The above detection control is repeated as shown in Q, r and S1 in FIG. As a result of the above, it is possible to reduce the required drive pulse width by Δe from e for all other pulse widths except for the fast-forwarding start pulse width, and drive current consumption can be reduced in the same way as in the case of BLD operation. Next, FIG. 6 shows a timing chart when the needle is corrected in reverse and fast forward.

First, in the case of reverse drive, three types of drive pulses given by the t and u signals in FIG. 6 are sequentially applied in one step drive.

This is a method in which the rotor 3 is forcibly vibrated with the first two pulses to give the rotor 3 momentum in the opposite direction, and then a third reversal drive pulse is issued to rotate the rotor 3 in the opposite direction. This method has traditionally been necessary to drive a step motor in reverse, which originally only had the function of forward rotation. Next, v in FIG. 6 is a current waveform, w is a chopper amplified voltage waveform of the current, and the section where the signal shown by the dotted line of w is Hi is the detection section. The optimum drive timing is detected from this chopper amplification voltage, and two types of next drive pulses as shown in FIG. 6, X and Y, are provided. With these,
The damped vibration of the rotor 3 can be used, and the energy of forced vibration required for reverse rotation can be reduced. In other words, the three types of drive pulse widths f originally required for reverse rotation drive shown in FIG. 6 t and u
Among ``, g'', and h'', f'' can be eliminated, and g'' can be reduced by Δg''. From the above, driving current consumption can be saved. The drive timing detection and control method that effectively utilizes the damped vibration energy of the rotor 3 in various cases where the step motor is caused to rotate continuously has been described above with reference to the timing chart.

Hereinafter, the invention will be described in detail about a detection control circuit and a drive circuit during forward rotation and fast forwarding of needle correction, which is a typical example of causing the step motor to rotate continuously. Figure 7 shows
This is a detection control circuit during forward rotation and rapid forwarding. Starting with detection, a signal shown at S2 in FIG. 5 is input to the input terminal 11 in FIG. The S2 signal is high only at the moment of the falling edge of the drive pulse.
Become i. The period from when this S2 signal becomes Hi to when it is detected is defined as a detectable period. However, in order to save current consumption for detection, the detection period should not exceed 200 TrLsec. This function is achieved by inputting the signal shown at S3 in FIG. 5 to the input terminal 12 in FIG. At the time of detection, the chopper amplified voltage on the terminal 01 side of the coil 3 is input from FIG. 7, 13, and the chopper amplified voltage on the 02 side is input from FIG. 7, 14. are detected by comparators 15 and 16, respectively, and 15 and 1
A detection signal is output from 6. Thereafter, this detection signal passes through a d''Msec delay circuit 33, thereby becoming a signal delayed by d''Msec. d″7TI.sec
It will be a delayed signal. Immediately after the signal delayed by d″Msec, counter 17 and SET-RESET-FLIP-Fl
Pulse width (e″-Δe″) Ms at OPl8, l9, 2O
From ec and terminals 20 and 23 (e″-Δe″)
Drive signals for RrLSeC are alternately output. Here, the process of generating a drive signal of (e″-Δe″)7TLsec will be explained in more detail. First, the counter 17 is reset by the detection delay signal 21, and then (e″-
An output signal is output from Qx after 7TLsec (Δe'').With this signal, SET-RESET-FLIP-FLOPl
8, 19, 2O are RESET. 18 is set in advance by the detection delay signal 21, so the output Q of 18 outputs a pulse width signal with a width of (e″-Δe″) 7 nsec.

This signal is SET-RESET-FLIP-FLOP
The drive signals are distributed by l9 and l9 and 20 and output alternately from terminals 22 and 23. here,
The detection timing of the damped vibration of the rotor 3 is determined by the direction of the induced current. Therefore, after the drive signal is output from the terminal 23, the detection signal is input only from 16, and after the drive signal is output from the drive terminal 22, the detection signal is input only from 15. do. This function is achieved by inputting the S4 signal of FIG. 5 to terminal 24. Furthermore, if the damped vibration becomes too small to be detected due to an unexpected factor, the drive pulse will not be generated next time, so the drive pulse will be forcibly output after 300 msec. This function is performed by connecting terminal 25 to S
This is achieved by inputting the signal S6 in FIG. 5 to the terminal 26. The above is an explanation of the detection control circuit during forward rotation and fast forwarding. Next, the drive circuit during forward rotation and fast forwarding will be explained according to the timing chart of FIG. 8 and the circuit of FIG. 9.

First, 10 and 11 in Fig. 8 indicate d″m・Se from the time of detection.
c, and is the moment of the next drive. Signals z and C1 in FIG. 8 are drive pulse signals output from 23 and 22 in FIG. 7, respectively, and by inputting these to terminals 27 and 28 in FIG. 02
A driving pulse is applied to the oscilloscope. After applying the driving pulse, the a1 and d1 signals in FIG. 8 are connected to the terminals 29 in FIG. 9, respectively.
and 30, and by inputting Kg and e1 in FIG. 8 to terminals 31 and 32 in FIG. 9, respectively, the above-mentioned chopper width is increased. By increasing the chopper width, the induced current due to the damped vibration of the rotor 3 is amplified as a voltage, which is detected by the detection circuit shown in FIG. The drive timing detection control during forward rotation fast forwarding for hand correction, which is a typical example of the present invention, has been described above using a specific circuit.

In this way, the present invention can effectively utilize the energy of the damped vibration of the rotor 3 in various cases where the step motor is continuously rotated, such as when rapidly moving a pointer, and can reduce the drive current consumption of the step motor. It is possible, and it is also possible to increase the speed of the pointer's rapid advance compared to before.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a conventional two-pole step motor for electronic wristwatches, which is also used in the present invention.

Figure 2 is a timing chart of conventional drive pulses, Figure 3 is a graph showing the relationship between rotor motion and current waveform when driving a step motor, and Figure 4 is drive timing detection control during BLD operation. timing chart,
Fig. 5 is a timing chart of drive timing detection control during normal fast forwarding of needle correction, Fig. 6 is a timing chart of drive timing detection control during reverse fast forwarding of needle correction, and Fig. 7 is a timing chart of drive timing detection control during forward fast forwarding of needle correction. FIG. 8 is a timing chart of the drive circuit during normal rotation fast-forwarding of needle correction, and FIG. 9 shows the driving circuit during normal rotation fast-forwarding of needle correction. In Fig. 1, 1 is a stator, 2 is a coil,
3 is a rotor, 4 is a statically stable direction, 5 is a neutral direction, 6 is a dynamically stable direction, and 7 is an inner notch. Figure 2. In,
The a and b signals are normal, the c and d signals are when BLD is activated,
Signals e and f are drive signals for forward fast forwarding, and g and h are drive signals for fast forwarding in reverse. Here, a'', b'' and C'' are the intervals of each driving step. In Fig. 3,
A is the motion of the rotor 3 during one-step ζ driving, and B is the current waveform flowing through the coil 2 in FIG. 1 at that time. Here, t1 is the end of the application of the drive pulse, and 8 and 9 are the timings when the direction of motion of the rotor 3 during damped vibration is the forward rotation direction and the reverse induced current is at its maximum. In the fourth diagram, i is the first drive pulse signal of two-step continuous drive,
j is the current waveform at this time, and k is the voltage waveform obtained by chopper-amplifying this current waveform only in the direction where the damped vibration energy, - can be effectively used for the next drive. Here, the dotted line signal of k is H
The interval i is a detection interval of 200rrLsec. Further, l is the next drive pulse signal. ! is the moment of detection. In FIG. 5, m is the start pulse signal for normal rotation fast forwarding, n is the current waveform at that time, o is the chopper amplification voltage waveform, and the period where the dotted line signal is Hi is 2000 WLsec.
This is the detection interval. p is the next drive pulse signal, and T3 is the moment of f detection. Q, r, and S are the drive signal, current waveform, and chopper amplification voltage waveform of the next drive pulse, respectively, and T4 is also the moment of detection. In addition, S2 is a Hl signal at the moment of the falling edge of the drive pulse, S3 is a signal delayed by 200 msec from the S2 signal, S is a signal that is inverted at the rising edge of the S2 signal, and S is the end of the drive pulse signal applied to the 01 side. The signal S6 after 300TrLsec from the time is 300ms from the end of the drive pulse signal applied to the 02 side.
This is the signal after ec. In FIG. 6, t and u are drive pulse signals at the start of reverse fast forwarding, respectively.
Apply voltage to the terminals 01 and 02. v is the current waveform at this time, w is the chopper amplification voltage waveform, and the period in which the dotted line signal is Hi is a detection period of 200 msec. Here, T5 is the moment of detection. Further, x and y are next drive pulse signals for reverse fast forwarding, and voltages are applied to the terminals 01 and 02 of the coil 2, respectively. In Figure 7,
15 and 16 are comparators, j″ and k″ are resistors,
The detection comparison voltage is created by dividing the voltage. 34 is an element for switching this resistance partial voltage, 33 is d″Msec
Delay circuits, 18, 19, 20 and 35 are SET-RES
ET-FLIP-FLOPll7 is a counter.

Further, 11, 12, 13, 24, 25 and 26 are input terminals of the detection circuit, and 22 and 23 are output terminals.
Further, 21 is an output signal of 23. In Figure 8,
z and C1 are drive pulse signals output from 23 and 22 in FIG. 7, respectively, a1 and d1 are chopper signals, and K
g and e1 are Hi signals only during the chopper section by the a1 and d1 signals, respectively. 10 and 11 are driving pulse application timings.

Claims (1)

[Claims] 1. In an electronic watch having a step motor and a drive timing detection control circuit, when the pointer is continuously fast-forwarded, the surplus drive energy of the step motor is effectively used for driving the next step without being consumed by damped vibration of the rotor. 1. A drive timing detection and control device for a step motor for a watch, characterized in that the drive timing at which the rotation is possible is detected and controlled from reverse induced current due to damped vibration of a rotor.