JPS58213279A - Analog electronic clock - Google Patents

Abstract

PURPOSE:To enlarge the maximum pulse width of a driving pulse, and to reduce the power consumption of a motor, by deciding a rotation and a non-rotation of a rotor by making reference voltage a boundary, and making a regular driving pulse cyclic. CONSTITUTION:When discriminating a rotation and a non-rotation of a rotor, it is decided to be a rotation when detecting voltage is above reference voltage VCOMP, and is decided to be a non-rotation when it is below VCOMP, by a comparator. When reference voltage is set, for instance, to 0.8V and the detecting voltage becomes smaller than the reference voltage, it is decided to be a non- rotation and a correcting pulse is outputted. It dose not occur that the hand operation of a clock is disturbed by an output of the correcting pulse. In case when a driving current is increased too much, however, the current is controlled by an up-down counter so as to operate cyclically. In this way, the maximum pulse width of a driving pulse is enlarged, probability of the correcting pulse is dropped, and the current consumption of a motor can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a control circuit for a method of driving a step motor of a multi-layered wristwatch in low gravity and to prevent detection malfunctions.

For step motors that require low power consumption, such as the ultra-compact step motor for Ichiko's wristwatches, one method of reducing power consumption is to reduce the power consumption of the step motor itself.

In addition to improving air-mechanical conversion efficiency, RA is normally maintained at low gravity.
A so-called correction drive method has been devised to quickly re-drive the rotor with more power than usual when the rotor does not rotate normally for some reason. When adopting this correction drive method, the important thing is how to reliably detect rotation or non-rotation of the ronita.

FIG. 1(A) is an example of a two-pole step motor that has been used to drive the hands of conventional electronic watches and is also used in the present invention. , which is an example of an inverted pulse that is conventionally used to drive a step motor with a common structure.

The stator 1 is magnetized by applying the drive pulse shown in Fig. 1+(B) to the coil 6, and the rotor rotates 1800 times due to the repulsion and attractive force with the magnetic poles of the rotor 2. Conventionally, the length of the applied drive pulse has been selected to be such that the output of the motor can be guaranteed under all conditions that should be guaranteed for a watch. However, this increases the calendar load,
It was necessary to include allowances for the high internal resistance of the battery, the decline in the maximum capacity at the end of its life, etc., and it was necessary to drive with a pulse width that had an allowance. Therefore, we improved this method by driving the step motor with a pulse width of just 9, which normally does not have much margin, and then equipping it with a detection circuit that determines whether the rotor has rotated or not. A method has been proposed in which corrective driving is performed with a conventional pulse width only when it is determined that the rotor is not rotating.To detect whether the rotor is rotating or not rotating, a special detection element, e.g. , mechanical contacts, Hall elements, etc., are difficult to implement due to the demands for smaller, thinner, and lower cost watches.

Therefore, we took into consideration the characteristic that the force generated by the vibration of the rotor after applying the drive pulse is different when the rotor is rotating and when it is not rotating, and the rotor is rotated.

A method is used to detect non-rotation.

The present invention aims to improve this correction drive system. FIG. 2 is a circuit example of a step motor drive and detection section used in the conventional method and in the present invention.

This circuit configuration separates the inputs of N-channel FBT gate (hereinafter abbreviated as N-gate) 41), 5b and P-channel FF1T gate (hereinafter abbreviated as P-gate), aa, and sa, and rotates and non-rotates the rotor 2. It is provided with detection resistors 6a and 6b for detecting and N gates 7a and 7υ for switching these resistors.

FIG. 3 is a time chart in the conventional correction drive method. The voltage applied to both ends of the coil causes a current to flow in the section shown in FIG. 3a, as shown in the flow path 9 shown in FIG.

Next, in the section shown in FIG. 3, the circuit is switched to a closed circuit including the detection resistor 6b like the closed circuit 10 shown in FIG.
A voltage generated by vibration of the rotor 2 after application of the drive pulse is generated at the terminal 8b. If a signal indicating non-rotation is already detected in the detection section, the current is passed through the coil 5 in the section C of Fig. 3 again in the flow passage 9 of Fig. 2, and the time opening specification is satisfied. The step motor is corrected and driven using sufficiently long pulses.

Next, the principle of rotor rotation/non-rotation detection will be explained in detail.

Figure 4 shows the current waveform when a current flows through coil 3 of a step motor with coil resistance 5 and 10,000 turns of Ω. This is the current waveform when the drive pulse length a is 59 mB, and the waveform is the same for each machine regardless of rotation or non-rotation.

The section in Figure 4 shows the induced current due to the vibration of the rotor 2 after the application of the drive pulse.

The mud waveform changes greatly when the rotor 2 is rotating, not rotating, under no load, and under load. The waveform bl in the section of FIG. 4 is the current waveform when the rotor 2 is rotating, and bt is the current waveform when the rotor 2 is not rotating.

The difference in current due to rotation and non-rotation can be converted into a voltage waveform and extracted.The drive detection circuit shown in Figure 2 was invented.
In the section b in FIG. 4, the circuit is switched to a closed circuit 10.

By doing so, the current generated by the vibration of the rotor 2 flows through the detection resistor 6b, so that a larger voltage waveform appears at the terminal 8b than when no detection resistor is attached.

In the closed circuit 10 of FIG. 2, the current flowing in the positive direction in the section is reversed to the detection resistor 6bKFi, so that it appears as a negative voltage.

Further, in the OFF state, the N gate 5b has a PN junction between the drain and the P-well, and functions as a diode with YES as the anode. Therefore, the negative voltage seen from the terminal 8b flows through the N gate 5b, which acts as a diode, and has an impedance similar to that of the closed circuit 11.
Braking force is applied to the rotor. The relationship between the plow of the rotor 2 and the detection signal will be explained using FIG. 5.

FIG. 5 shows the relationship between the stator 1 and the rotor 2, and FIG. 5(A) shows the rotor 2 in a static state. , 16b, and outer peripheral notches 15a, 15b for integrating the stator. , fl:, If there is a two-body stage, it is 15a.

The stator is separated at a portion 15b.

When the rotor 2 is at rest, the inner peripheral notch 16a.

The N and S magnetic poles are stationary at approximately 90 degrees with 16b.
FIG. 5(B) is a diagram when a driving pulse is applied to the rotor, and the rotor rotates in the direction of the arrow.

Since the driving pulse width is as short as 3.9 m gB6, the pulse ends when the shaft is rotated near the inner circumferential notch. When the load is small, the rotor can rotate completely due to its inertia, but when the load is heavy, it cannot rotate completely and the rotor rotates in the opposite direction, as shown in FIG. 5(0). At this time, the magnetic poles of the rotor 2 pass near the outer peripheral notches 15a and 15b, which generates a large current in the coil. However, at this time, since the circuit 10 is closed as shown in FIG. 2, a negative voltage is generated at the terminal 8b, as explained earlier, and a diion forward current flows through the N gate 5b. Braking is applied to the rotor 2. Therefore, the rotor 2 is rapidly decelerated, and after that, the voltage and pressure generated by the vibration of the rotor 2 are small.On the other hand, when the load is small and the rotor 2 rotates, as shown in FIG. 5(D), The rotor 2 rotates in the direction 19. At this time, the magnetic flux generated by the rotor 2 flows through the outer peripheral notch 15a.

Since the direction is perpendicular to 15b, the induced current C is initially small. Further, when the magnetic poles rotate to near the outer peripheral notches 15a, 15b (7), a large current is generated.

At this time, since a negative tEE is generated at the terminal 8b of the closed circuit 10, the rotor is braked due to the diode effect of the N gate 5b. Further thereafter, when the rotor rotates too much from the rest position shown in FIG. 5(A) and returns to the rest position, a voltage that can detect the rotation of the rotor 2 is generated at the terminal 8b in FIG.

The voltage waveform 20 in FIG. 6(A) is the voltage waveform at the terminal 8b when the rotor 2 described above rotates. The period a is the drive pulse application time of % 5.9 WL qg2.

Is the circuit in this case the current path in Figure 2? and VDD:1
．． It is 57V.

Section b in FIG. 6(A) is the normal pressure induced by the vibration of the rotor, and is the voltage waveform at the time of the closed circuit 10 in FIG. 2. The negative voltage is clipped at approximately -0.SV due to the diode effect of the N gate 5b, and the peak of positive normal pressure is α4. On the other hand, waveform 21
is the non-rotating case, but the peak of positive voltage is O,'I
By distinguishing the two voltages below V, it is possible to determine whether the rotor is rotating or not.

Furthermore, although the difference between these two voltages is small, it can be easily amplified by the method described below. Figure 6 (
In the section shown in b of A), closed circuit 10 and closed circuit 1 in FIG.
Switch 1 to Kouhiro. In the closed circuit 11, N gates 4b and 5b io.

Since both ends of the coil 30 are short-circuited with an element having an ON resistance of about Ω, the female current due to rotor vibration is large.

However, when switching to the closed circuit 10, the coil 5
The current 1i momentarily flows through the detection resistor 6b due to the haze of the inductance component. Therefore, the induced heavy pressure waveform 20 caused by the rotor 2 during rotation, in which an instantaneous high peak voltage is generated, is applied to both ends of the detection resistor in the closed circuit 10 of FIG. When the closed circuit 11 is switched alternately, the voltage waveform at terminal 8b becomes as shown in Figure 6 CB). The time axis expanded waveform of voltage waveform 22 and 23 at this time is shown in Figure 6 (0). . At this time, the peak voltage is delayed by about 60 μm after switching to the loop 10. This is because there is a cavantance component between the drain and the source of the N gate 5b, which causes a delay in the peak voltage.

In recent years, such a method has been proposed, and it has become easier to detect whether the rotor is rotating or not. By using this detection method, it is possible to use the above-mentioned method in which the normal drive pulse width is fixed and to further reduce the power consumption of the step motor. A system has been realized in which the fA pulse width is rotated and driven at the lowest pulse width.

FIG. 7 is a graph showing the relationship between the drive ηf reharse width and the torque of the step motor used in the conventional and present example of a heavy-duty clock.

In the case of fixed pulse drive, f is set at the point of drive pulse width Fia in order to guarantee the maximum torque +q max of the step motor. The method of performing correction drive is Tq
c If the 0 point is the torque required for curling feed, the length of the normal drive pulse is a t = 3.4 mrx or a!
The length is set to =19rnw. The reason is that when the rotor cannot rotate completely with the normal drive pulses, a correction pulse is added to the fourth one, so if the correction pulses appear too many times, the current consumption of both is added, which causes the current to increase. This is because it is also possible that the amount increases.

However, in reality, even with a pulse width of a6 = 2.4 m, the rotor rotates when there is no load, so if the rotor can be driven with this pulse width, it is possible to further reduce consumption.

The operation will be explained with reference to FIG.

Normally, a step motor is driven with a pulse width of a (1 = 2.4 mH), and when the rotor cannot fully rotate with a pulse width of a0 due to a calendar load, etc., a detection circuit detects that the rotor is not rotating. is determined and immediately drives with a correction drive pulse.The pulse width of this correction drive is generally a in Fig. 7.
A pulse width of = 7.8271 sec is used, and the drive pulse width after the next second is a(3=2-A
m! A pulse width of a I=2.9 m, which is slightly longer than +ec, is automatically set as the normal drive pulse, and the drive pulse is applied to the step motor. However, according to the example in Figure 8, % a I =2.9 ttL
Since the calendar torque Tqc is not reached even at yy2, the rotor does not rotate again υ, and the immediate correction pulse a = 7.8
Driven by ngy2. Then, the normal drive pulse after 1 second will automatically be a! =54 WLsec. Since the output torque in this case is larger than the calendar torque Tqc, the step motor is thereafter driven with a pulse width of a1w54myyt2 per second.

However, until this age, the pulse width of az=5.4 mgPt2 continues even when the calendar load is removed, which is disadvantageous for reducing the power consumption sr2. Therefore, by adding a circuit that shortens the drive pulse every N seconds,
When N times a = 5 atFlsec are output continuously, the pulse width returns to a + = 2.9 mgB2. Furthermore, when al is output N times in succession, it becomes al). Conversely, if non-rotation is detected at the normal drive pulse σ) maximum pulse width at=3.91Rsec, a correction pulse is output.
In the next 1 second after Ic, a@ = 3. same as last time.
9 m yg2 is output. In this way, in order to set the normal drive pulse to one of the planks, the ninth
An up/down counter as shown in the figure is required.

As explained above, it is possible to detect whether the rotor is rotating or not, and it is possible to drive the step motor with the lowest possible pulse width than the normal drive pulse width, thereby reducing the power consumption of the step motor. Ta. However, the conventional example of one-liner has a major drawback. This can be explained with reference to Fig. 10. Fig. 10 (t) shows the relationship between the normal drive pulse width and the detected heavy pressure. When the pulse width exceeds a certain value, the detection 11frE decreases rapidly.

This is because when the normal drive pulse width becomes thicker, the rotor is attracted to the magnetic poles and the imaging is attenuated. Further, the value of this characteristic curve changes depending on the motor. In the past and in the present invention, in order to distinguish between rotation and non-rotation of the rotor, the detected heavy pressure is determined by a comparator to be rotating if it is above a certain reference heavy pressure VOOMF, and non-rotating if the detected heavy pressure is below yOOMF. I judge that. All of the above controls are performed by an electronic circuit built into the watch. As shown in FIG. 10, youup = 0.
When set to 8 V, if the rotor rotates at a3=59mgy2, detection 1. The pressure is approximately 0.9V, and the watch's electronic circuit determines that it is rotating.However, since the value of this characteristic curve varies depending on the motor, the detected pressure when the Rogue is rotating is aH
= 3.9 m5ec, y OOMF = 0
．． It may be less than 8 V. In this case, the electronic circuit of the watch determines that it is not rotating and outputs a correction pulse. The correction and pulse output do not disturb the movement of the clock's hands. However, a large force and current flow due to the output of the correction pulse. Similarly, the detection voltage due to the next rotation is v
When it becomes smaller than coup = 0.8 V, it is determined that it is not rotating, and a correction pulse is output. In this way, correction pulses are output one after another, and the speed and flow required to rotate the rotor of the step motor increases rapidly.

Once a conventional rotation detection control circuit enters such a state, it continues to be in that state and cannot escape from that state. Therefore, in conventional circuits, by design, usually r
It is not possible to widen the AA pulse width. In this case, the probability that a correction pulse will be output increases, and the current consumption increases.

FIG. 11 is a block diagram of the electronic circuit of the conventional electronic timepiece and the present invention. Reference numeral 51 denotes an oscillation section, in which a time reference signal is generated by a crystal oscillator. This signal is frequency-divided by the frequency dividing section 32 to form a plurality of frequency signals.

This signal enters the waveform shaping section 55 and is AND gated with the step motor drive pulse, timing pulses necessary for detection, etc.

Synthesize using OR gates, flip-flops, etc. The drive/detection section 55 is composed of the circuit shown in FIG. 2 and a comparator for determining the detection signals outputted to 8a and 8b. Furthermore, the step motor drive output is tangential to the step motor 66. The detection signal of the detection Its is fed back to the control section 64.

FIG. 9 shows an up/down counter for controlling the normal driving m pulse included in the control section of FIG. 11. 'When 63 becomes a logic level high when inputting Ichihara, the counters 53 and 51 are initialized, and the output signals α and β become a logic level low. (Hereinafter, a high logic level will be indicated as 1, and a low logic level will be indicated as φ.) The up signal S1 and the down signal S are normally at φ. As mentioned earlier, when it is determined that the rotation is not occurring, Sl becomes 1, and the normal state φ is established. By doing this, α becomes 1, Sl
is 1. When φ is repeated, α and β change from 1 to A4 as shown in Table 1, and when α=1°β=1, they do not change any further. Also, as mentioned earlier, after a certain period of time, for example 80 ki, has passed, St will be 1. φ, and α and β change from 164 to 1, contrary to the previous case, and α
=φ.

When β=φ, there is no further change. By setting the pulse width of the normal drive pulse using the α and β signals, training 1 of the normal drive pulse with rotation and non-rotation as described above can be performed.

Table 1 This explanation is based on a 2-bit up/down counter, α and β, for simplicity, but in reality, 3 bits or more is possible, and in the case of 3 pits, a normal pulse width of 8 steps is possible. It is. If we apply the above explanation to this circuit, we will see that the state α=1°β21 continues.

In order to eliminate these drawbacks, the present invention makes the change step of the normal drive pulse cyclic. The numbers are the same as in FIG. 12th
The figure is a circuit diagram of an up/down counter of the control section in the present invention. S3 is 1. When it comes to φ, α=φ, β=φ
is initialized to . When the rotor of the step motor is not rotating, the up pulse St is 1. φ, and α=1. β=
It becomes φ. After that, the optimum normal pulse width is selected and the values of α and β are set. In the present invention, in the example explained in the conventional example, for example, when V OOMP is O, 8V and the normal drive pulse is a B = l 9tn (8), the detected heavy pressure is still detected even though it is rotating. yaoMp -
= 0.8 V or less, about 0.7 V. In this case, the detection circuit determines that it is not rotating, sets Sl to 1, and φ
Make it. At this time, in the conventional example, counting up was prohibited by the AND gate 41, but in the present invention, the counter is counted up, α=φ, β=φ
becomes. By doing this, it is possible to escape from the undetectable leaning castle. After escaping, select the optimal normal drive pulse width and stabilize. , Mata Downpulse S! As in the conventional example, when the normal drive pulse width becomes the minimum, the AND gate 54 prohibits the countdown. As described above, by making the normal drive pulse cyclic, the maximum pulse width of the normal drive pulse can be increased in terms of design. If the maximum pulse width of the normal drive pulse is increased (by doing so, the rotation detection malfunctions and the rotation is determined to be non-rotation), immediately escape from that state and select the optimal normal drive pulse width. .

Therefore, by increasing the maximum pulse width of the normal drive pulse, it is possible to lower the probability of a correction pulse and reduce the motor's extinction current.

It also eliminates detection failures due to manufacturing variations in the motor.
can be completed. In the past, the normal drive pulse was set depending on the type of motor, but since the setting range is expanded, there is no need for this in the present invention. The effects of the present invention are very large, such as being less complicated and extremely safe against erroneous rotation detection.

Further, the detection method according to the present invention can be applied not only to the range stated above, but also to all methods of detecting the induced heavy pressure of a step motor. Furthermore, in the present invention, the state of dynamic energy given to the step motor is realized by changing the pulse width of the drive pulse, but other methods, such as changing the waveform and duty ratio of the drive pulse, can be used. The scope of its application is extremely wide, as it can also be achieved by methods such as changing the current value.

[Brief explanation of the drawing]

FIG. 1(A) is a perspective view of a step mode for an electronic watch used in the conventional and present invention, and FIG. 1(B) is a
A conventional step motor drive pulse waveform diagram. The second section 1 is a part of a drive and detection circuit diagram of a step motor according to the prior art and the present invention. FIG. 3 is a step motor drive pulse waveform diagram of the conventional sight line drive method. Figure 4 shows current waveforms of the step motor and current waveforms induced by rotor vibration when the rotor is rotating and not rotating. Figure i5 (A) is a relational diagram of the stator and rotor when the rotor is stationary. FIG. 5(B) is a diagram showing the rotational direction of the rotor when driving pulses are applied. FIG. 5(0) is a diagram showing the movement of the rotor when the rotor cannot rotate. 11th (D) is a diagram showing the movement of the rotor after applying a drive pulse when the rotor rotates. Figure 1gb (A) shows the air and pressure induced in the detection resistor when the rotor is rotating and not rotating. Figure 6 CB) ili′, the rotor is rotating and non-rotating,
Voltage waveform induced in the detection resistor when switching a closed circuit with high resistance and a closed circuit with low resistance. Figure 6 ((j) is an enlarged view of the waveforms in Figures B 22 and 230. Figure 7 is a characteristic diagram showing the relationship between drive pulse width and minute hand torque. Figure 8 is a diagram showing the relationship between drive pulse width and minute hand torque. Figure 8 is a diagram showing the relationship between drive pulse width and minute hand torque. A drive pulse waveform diagram showing a correction drive method in which the voltage changes. Figure 9 is a circuit diagram of an up-down counter for setting normal drive pulses in the conventional example. Figures 10 and 10 show the normal drive pulse width and detection voltage. Fig. 11 is a block diagram of the weight circuit of the electronic timepiece in the conventional and the present invention. Fig. 12 is a circuit diagram of the up/down counter of the control section in the present invention. 1. ...Stator 2...Rotor 3...Coil 101...Gate terminal 102...P of r game) 4a
Gate terminal 105 of gate 5a...gate terminal 106 of N gate 4b...gate terminal 41 of N gate 7b.
44.4B, 52.54...AND circuit 42.45.
49...NOR circuit 43.46, 47.50 ・
. . . NOT circuit 51, 53 . . . is a flip-flop circuit with reset. Applicant: Ewa Seikosha Co., Ltd. Agent, Patent Attorney: Mogami Mukai 2 Zuyoko 3

Claims (3)

[Claims] (1) Consisting of at least an excavation circuit 2 frequency divider circuit, a pulse width synthesis circuit 1 rotation detection circuit, a step motor, and a small battery for power supply, the drive state of the step motor changes when the drive conditions change, and the drive state changes. In a child clock that has a plurality of hanging states, at least one drive state sequence A that has a plurality of states that can be in the drive state t and a drive state sequence A that has a larger drive energy than any of the possible states of the drive state sequence A. Two drive states B are prepared, and in normal step motor drive, any one of the drive state series A is selected, and if the rotation detection circuit determines that the rotation is not rotating during normal step motor drive, the drive state is State B is immediately output, and in the next step motor drive, any one of the drive state series A with higher drive energy than any one of the drive state series A selected in the previous drive is selected. select the state having the maximum drive energy in the drive state sequence A in normal driving of the step motor, and if the rotation detection circuit determines that it is not rotating, immediately outputs the drive state B; An analog electronic timepiece characterized in that the state having the minimum drive energy in the drive state sequence A is selected in the next step motor drive. (2) The drive energy state of the drive state sequence A is set by the output signal of the up-down counter or the up-counter, and the up-signal input to the up-down counter or the up-down counter is used to drive the normal step motor. This occurs when the rotation detection circuit determines non-rotation, and in all cases, the up signal is the output of the up/down counter or the up counter (
K M The analog electronic timepiece according to claim 1, which changes the state. (3) The analog city clock according to claims 1 and 2, wherein the drive state sequence A and the drive state B are formed by a combination of changes in pulse width.