JPS5913971A - Analog electronic timepiece - Google Patents

Abstract

PURPOSE:To eliminate the need for resistors to be externally mounted and to reduce the size, thickness and cost of a timepiece with reference to an analog electronic timepiece which detects the rotation and non-rotation of a rotor by detection pulses and drives a motor by always optimum pulse width so as to reduce electric power consumption by enabling the logical setting of detecting resistors within an IC. CONSTITUTION:A detection circuit consists of p gates 43, 44, n gates 45, 46, detecting resistor elements 47-54 with parallel constitution, AND circuits 55-62 and n gates 63, 70 serving as switching elements for automatic setting of the detecting resistors. The control signals S1, S2, S3, S4 of the n gates are so constituted as to permit selective setting of the detecting resistors. More specifically, the N gates turn on at S1=1 (logical level H), by which the r1 resistor element is selected. The gates turn off at S1=0 (logical level L) and no resistors are selected. The ame holds true of r2-r4. e, e' are the signals to determine on which side of an O1 terminal or O2 terminal the detecting resistor RS is to be set. More specifically, the resistor is set on the O1 side at e=0 (e'=1) and on the O2 side at e=1 (e'=0).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an analog electronic timepiece that detects rotation or non-rotation of a rotor using detection pulses, always drives a motor with an optimal pulse width, and achieves low power consumption.

Conventionally, a driving method has been proposed in which current is passed through a coil of a step motor using detection pulses to determine whether the rotor is rotating or not, and the width of the normal drive pulses supplied to the step motor is controlled. This aims to always supply the optimum pulse width that matches the output torque state of the step motor and the load state of the wheel train, thereby achieving lower power consumption in analog electronic watches.

FIG. 1 shows a pulse waveform applied to a coil when determining whether the rotor is rotating or not rotating based on detection pulses. 1 is a drive pulse, which is output with a pulse width that is expected to be most suitable based on the output torque state of the motor and the load state of the wheel train at that time. 2
is a detection pulse, and it is determined whether the rotor is rotating or not. Reference numeral 3 denotes a correction pulse that is output to return the hand movement to normal when it is determined by the detection pulse that the rotor is not rotating.

Here, the principle of rotation determination using detection pulses will be briefly described. Suppose now that the magnetic poles of the rotor were in the position shown in FIG. 2 before the drive pulse 1 was output. When the drive pulse 1 is output, the coil is excited, and a magnetic flux is generated as shown in 8. If the width of the drive pulse 1 is sufficient to rotate the rotor, the rotor will rotate to the position shown in Figure 3 (α), and if it is insufficient, the rotor will not rotate and remain in the same position. The position will be as shown in figure (b). First, considering the case where the rotor rotates (Fig. 3 (a)), in the saturable part near the outer seven notches 7-a and 7-b, the magnetic flux 9 due to the rotor magnet flows from left to right. is passing. When the coil is excited by the detection pulse 2 in this state, a magnetic flux 10 is generated as shown in the figure and attempts to pass through the oversaturation section. At this time, in the supersaturation portion, the magnetic flux 10 is in a direction that tends to cancel out the magnetic flux 9 caused by the rotor magnet, so the magnetic resistance is small, and therefore the inductance of the coil is large. Therefore, the current due to the detection pulse (hereinafter referred to as detection current) is 25 (25') in Fig. 5 (α).
) shows a gradual rise. On the other hand, when the rotor is not rotating as shown in FIG. 3(b), the magnetic flux 11 due to the rotor magnet passes through the saturable portion from right to left.

In this state, when the magnetic flux 12 caused by the detection pulse attempts to pass through the saturable portion, the magnetic flux is already saturated or almost saturated in this direction, so that it is difficult for the magnetic flux to pass through, that is, the magnetic resistance is high.

Therefore, the inductance of the coil is small, and the detected current shows a rapid rise as shown at 24 (24') in FIG. 5(a). By determining the difference in the rise of the current shown in FIG. 5 (α), it is possible to determine whether the rotor is rotating or not.

FIG. 4 shows a conventional circuit configuration for determining the difference in the rise of this current. In the same figure, 14.15 is P
Channel MosymT (hereinafter abbreviated as P gate), 16
．． Reference numerals 17, 20, and 21 indicate N-channel MO8FETs (hereinafter abbreviated as N gates), and 18 and 19 indicate resistance elements (hereinafter referred to as detection resistors) for determining whether the rotor is rotating or not rotating.

Now, suppose that the detection current flows in 22 loops.

P day 1-14, at the same time as the detection pulse ends by turning off the N gate 17, the N gate 16.21
When turned on and the detection current flows through the detection resistor 9 as shown in 23,
A voltage proportional to the current value is generated across the detection resistor.

Figure 5(b) shows the voltage at point 02 at this time (i.e. the detected voltage)
26 and 27 are the detected voltage waveforms for non-rotation and rotation, respectively. Peak value i of detection current
If the value of the detection resistor of 18.19 is R8, then between u and ir and the peak values of the detection voltages Vu and Vr, Vu+Rs i , Vr+Rs i r =
The relationship il) holds true. By determining whether these vu and vr are higher or lower than the reference voltage vth using a voltage comparison element such as a comparator, it is possible to determine whether the rotor is rotating or not. Now, in this conventional method, as shown in equation (1), Vu<Vu, and V7 is proportional to the detection resistor R8, so variations in the detection resistance value immediately appear as variations in the detection voltage. Therefore, it is necessary to create a detection resistance value with high precision. This detection resistor is desired to be constructed inside the IO by P- diffusion, P+ diffusion, ion implantation, etc. in order to make the watch smaller, thinner, and lower in cost. is extremely severe and impossible to create with high precision (for example, ±50 to 100% for P″ diffusion, ±20% for ion implantation).
% variation in resistance value must be taken into account)
.

Therefore, if this method is used, the detection resistor must be provided outside the circuit 0. This is extremely disadvantageous in response to demands for smaller, thinner, and lower cost watches. Furthermore, if the detected current varies due to variations in coil specifications or mechanical dimensions of the stator, rotor, etc., since the detection resistor is fixed, the detected voltage will immediately vary as shown in equation (1). appears. FIG. 6 shows this situation. As shown in the figure (a), for some reason the peak value of the detected current is iu-"iu', :r
-"ir", the detection voltage is also Vs-V'u'.

A worst case situation is also expected in which Vw' is also determined to be rotating due to the shift from vr to ■r' and b) <'7th.

Even if this is not an extreme example, variations in the detected current of each step motor will narrow the margin for immediate rotation determination, so consider variations in coil specifications and mechanical dimensions of the rotor/stator, etc. It is necessary to set various constants using the method, which imposes a large burden on design and experimentation. These issues are a major hindrance to the efforts to standardize watch movements and IO.

The object of the present invention is to eliminate such conventional drawbacks, provide a rotation detection circuit that requires no external resistance, and achieves miniaturization, thinness, and low cost of watches. be. Yet another object of the present invention is to absorb variations in characteristics of step motors by setting detection resistors that best match each step motor. Still another object of the present invention is to make a single specification 0 applicable to the pulse width control system of any integral stator type step motor, thereby contributing to the standardization of the 0.

Specifically, while taking into consideration that the resistance value built into the circuit C varies depending on the manufacturing conditions, the structure is such that the resistance value can be logically varied within a certain range. The above objective is achieved by selectively and automatically setting the most appropriate detection resistance value that matches the step motor when the battery is inserted into the watch or when the clock is turned off.

Hereinafter, the present invention will be described in full detail with reference to Examples.

FIG. 7 is a block diagram showing a configuration example of the present invention. In the figure, 32 is an oscillation circuit, 63 is a frequency dividing circuit, 34 is a pulse width synthesis circuit, 35 is a detection resistance setting circuit, 66 is a rotation detection circuit, 37 is a drive circuit, 38 is a step motor, and 39 is a wheel train. .

FIG. 8 shows an embodiment of a drive circuit and a detection circuit realizing the present invention. 45.44 is a P gate, and 45.46 is an N gate. Further, 47 to 54 are detection resistance elements arranged in parallel, and 55 to 62 are AND circuits. Also,
63 to 70 are N gates serving as switching elements for automatic detection resistance setting. 81, S2. S3. S4 is this N
This is a control signal for the gate, and is configured so that the detection resistor can be selectively set. That is, when 5i=1 (logic level H), the N gate is ON and the r1 resistance element is selected, and when S1=O (logic level L), it is OFF and becomes unselected. The same thing applies to r2 to r4. Therefore, the relationship between the control signals S1 to S4 and the detected resistance value Rs is expressed by the following equation.

Further, e and e are signals for determining which side of the 01 terminal or the 02 terminal the detection resistor Rs is set to. That is,
e-0 (τ = 1) is set to the 01 side, e-1 (Jin = 0
) is set to the 02 side.

Note that it is possible to set the detection resistance values between 01-(11' and 02-02' to different values, respectively), but since there is no difference in characteristics depending on the direction of the current flowing through the coil, it is possible to set different detection resistance values between 01-(11' and 02-02'). It doesn't make much sense to set it.Therefore, from now on, between 01-01' and 02
The following explanation assumes that the detection resistors between -02' are set to the same value.

Further, FIG. 9 shows an embodiment of the detection resistor setting circuit.

Next, as an example of setting the resistance values, the values of r1 to r4 are set to 50Ω, 30Ω, and 25Ω, respectively.

The case where Ω is set to 20 will be described. Also, MOSFE
The ON resistance of T is calculated as 1.6 KΩ to 10Ω, taking into account the variation due to the internal manufacturing process. This value is a well-proven value considering the current process capability. Variations in the ON resistance of these MOSFETs,
Table 1 shows the relationship between the control signal and the detected resistance value in FIG. 8, taking into account the manufacturing variation (±20%) of each resistance element. Here, RsMAX.

Rs typ and Rs min represent the detected resistance values when the manufacturing variation is maximum, no variation, and minimum, respectively.

[Table 1] Now, the peak value VU of the detected voltage during non-rotation is the power supply voltage V
Assuming that the detection resistance value equal to DD is 15Ω, in the case of this example, the variation MIN, typ.
Ω, 15 to the detection resistor 156, respectively, depending on min.
．． 6 KΩ, Ω is set to 159. For example, when Ω is set to Fffl at 156, the MOSFET control signals 81, 82, S3, and S4 are each set to H.
, H, L, H. In this way, in the method of automatically setting the detection resistance using resistance elements arranged in parallel, it is possible to automatically set the detection resistance in consideration of the ON resistance value of the MOSFET.

Next, the operation of automatic detection resistance setting will be explained in detail.

FIG. 10 is a timing chart showing one embodiment of the present invention, and shows signal waveforms at each terminal in FIG. Section A in the figure is a detection resistance setting section, and within this section a detection resistance value R8 suitable for each step motor is set. The period after section A is a normal operation section, and the step motor is driven with the optimum pulse width that matches the output torque state of the motor and the ftk previous state of the wheel train without determining whether it is rotating or not. Since the present invention does not specify this normal operation section, detailed description thereof will be omitted here. Further, the detection resistance setting section A is provided, for example, immediately after the battery is inserted or immediately after the reset is released. In this section A, PJ:j, Pi2 are large output pulses (hereinafter referred to as initialization pulses) to ensure that the rotor is at the desired position, and Pθ is the magnetic output pulse caused by the initialization pulse Pi1. Degaussing pulses for controlling hysteresis conditions, Psi, Ps2.・
°...Psn is a detection pulse for setting the detection resistor.

Indicates the pulse width used experimentally tP i 1 =
P i 2:=(,8?1Ieec, p6==Q,7r
nfl[1e, Psi, Ps2-s.

Psn = 0.36 mBBc.

Here, initialization pulse P71, Pi2, demagnetization pulse Pe
, detection pulses Ps, Psi to Psn will be explained using the magnetic hysteresis curve of the stator saturable portion. FIG. 11 shows the hysteresis curve. In the figure, Ho and -Ho indicate the strength of the magnetic field applied to the saturable part by the rotor magnet when the rotor is in a statically stable position. Assume now that the position of the magnetic poles of the rotor was as shown in FIG. 12 before the initialization pulse p7+ was applied.

In the figure, if arrow 79 is defined as the positive direction of the magnetic field, this state is a state in which a magnetic field of -H8 is applied to the saturable part, so a point on the / and l lines of the hysteresis curve in Figure 11. This indicates that Which point on this x'y' Mj is taken depends on the magnetic history. Assume that it was at the position X' before the initialization pulse P41 was applied. Assume that an initialization pulse Pi+ is applied and a magnetic flux 81 is generated in a direction that rotates the rotor as shown in FIG.

Since this Pil is a large output pulse, the rotor will definitely rotate and will be in a position as shown in FIG. 14. At this time, on the magnetic hysteresis curve shown in FIG. 11, it follows a history as indicated by an arrow 82 and reaches a point on the zv edge line. The position on this line depends on the magnitude of transient vibrations that occur when the rotor rotates. For example, Figure 21 shows the waveform of the current flowing through the coil when a pat pulse is applied.1. However, when the pz+ pulse is relatively short and the induced current due to transient vibration is large, as shown in (α), it is located at a point close to point V on the magnetic hysteresis curve, and conversely, as shown in (b), the Pi1 pulse When is relatively wide and the induced current due to transient vibration is small,
Located at a point close to point X. P i + = shown earlier
For a large output pulse such as 6.8g1fl&, the position should be close to two points.

In the explanation so far, if the position of the rotor before outputting the initialization pulse p7+ and the direction of the magnetic flux due to the initialization pulse p<+ are as shown in Fig. 13, that is, in the direction in which the rotor rotates. The explanation has been based on applying Pii. However, since it is necessary to prevent the hands from moving for the first second after the reset is canceled, if the detection resistor setting period is set immediately after the reset is canceled, the direction of the current due to the initialization pulse p7+ will be the same as the current immediately before being set. Must be in the same direction. Therefore, in this case, pz+ is applied not in the direction of rotating the rotor, but in the direction of attracting the rotor. Therefore, the magnetic state at this time is at point X before the output of Pi1 on the hysteresis curve J2 in FIG. 11, and at point 3 after the output of Pi1.

In either case, the magnetic hysteresis state after outputting Pi1 is at point X in FIG.

Next, the role of the demagnetizing pulse pe will be explained.

This degaussing pulse Pθ is applied in the opposite direction to the initializing pulse p(+). FIG. ” in one direction).

This demagnetizing pulse Pθ has a small pulse width (for example, Q,
7 tn8oc), it is insufficient to rotate the rotor, so the rotor does not rotate and is in the position shown in Fig. 16. The magnetic hysteresis state at this time is shown in FIG. 11 by tracing a herb like an arrow 84 from point X to point V.

Next, the operation of the detection pulses Ps1 and Ps2 *e Psn will be explained. The detection pulse is a demagnetizing pulse Pθ
is applied in the same direction as Figure 17 shows the state of the rotor at this time and the direction of the magnetic flux 85 due to the detection pulse.
The direction is the positive direction (+ direction). At this time, the magnetic hysteresis state traces a loop from point V in FIG. 11 as indicated by arrow 86 and returns to point V again. At this time, since the magnetic permeability μ-dB/dH in the saturable portion is small and the magnetic resistance is large, the inductance of the coil becomes small. Therefore, the current rise due to the detection pulse is rapid.

Next, the operation of the second initialization pulse P (2) in section A' will be explained. Fig. 18 shows the rotor position when Pi2 is applied and the magnetic flux 87 due to Pi2. p72 is Since it is a large output pulse, the rotor always rotates and its direction changes as shown in FIG. 19. At this time, the magnetic hysteresis state follows a loop as shown by arrow 88 in FIG. 11 and reaches point 22.

Next, the operation of the detection pulse 72 in interval AI will be explained. FIG. 20 shows the position of the rotor when Ps is applied,
It shows the magnetic flux 89 due to P8. At this time, the magnetic hysteresis state follows a loop as indicated by arrow 90 in FIG. 11 and returns to point 22 again. At this time, the magnetic permeability μ is large and the magnetic resistance is small, so the inductance of the coil becomes large. Therefore, the current caused by the detection pulse Ps shows a gentle rise.

The above is the initialization pulse p< in the detection resistance setting section A.
+, ps2, degaussing pulse pe, detection pulse P8, Psl
...This is an explanation of Pan's operation.

Next, the detection resistor setting operation in the detection resistor setting section A will be explained according to the timing chart of FIG. First, the detection pulse Pet Ps2. in section A'.・
...The operation of Psn will be explained first.

When the detection pulse Pal is output, the control signal 8
1. S2. S! ', 84 output HlH, H, and H, respectively, and the resistive elements r1 to τ4 are used. The current caused by the detection pulse flows in a loop as shown in Figure 8, 41, and after the detection pulse ends, it flows through the detection resistor in a loop as shown in 42, so a voltage proportional to the detection current is generated at the 02 terminal, which is the negative end of the coil. arise. This is the voltage 71 at the 02 terminal in FIG. Next, when the second detection pulse Ps2 is output,
s, , 5. s4 are L, H, respectively.
H, H are output, and at this time a voltage 72 is generated at the 02 terminal. Below, the detection resistance increases step by step every time a detection pulse is issued, so the detection voltage is also 75, 74.7.
51...76, which increases in proportion to this increase. As the detection resistance increases, a time will eventually come such as 76 when the detection voltage exceeds the reference voltage y tb'. By setting this reference voltage v tb' to the power supply voltage VDD or a value as close to this as possible, the difference between the detected voltages Vr and Vu during rotation and non-rotation during normal operation can be increased, and therefore You can have a large margin for determining rotation. Therefore, the detection resistance value that provides M and FE that exceed the reference voltage V th' (-V DD) for the first time becomes the detection resistance value that best matches the characteristics of the step motor. FIG. 22 shows how the voltage at the 02 terminal, that is, the detection voltage increases when the detection resistance value increases stepwise. In the figure, V sn is the first reference voltage v th' (-
V DD ), and the detection resistance value that provides V an is set as the optimal detection resistance.

Next, the operation of section A' within section A will be explained. This section A# is a section for confirming that the detection resistance value set in section A' is appropriate. As mentioned above,
Since the second initialization pulse P (2) is a large output pulse, the rotor is sure to rotate. Therefore, the detection current caused by the detection pulse P8 shows a gentle rise, so the detection resistance Rs set in the section A' is When a detection current is passed through the detection voltage, the detection voltage has a small peak value as shown at 77 in Fig. 10. 91 in Fig. 23 shows an enlarged view of this voltage waveform. If it is confirmed that the peak value Vr of 91 is smaller than the reference voltage vth, it is confirmed that the value of the detection resistor set in section A' was appropriate (
A voltage waveform 121 indicated by a dotted line in the figure is a detected voltage waveform generated by the detection pulse PBn in section A').

In the above explanation, we explained the method of searching for the optimal detection resistance by gradually increasing the detection resistance from the smallest one, but conversely, there is a method of gradually decreasing the detection resistance from the largest one. However, there is no difference in achieving the purpose of the present invention. FIG. 24 shows the change in detected voltage when this method is adopted. In the same figure, the detection voltage waveform changes from 93 to 94 as the detection resistance is decreased step by step.
→95-...→98→99.

VC is a voltage clipped by the diode characteristics of the P gate, and the peak value of the detection voltage is regulated by VC.

The time when the peak value of the detection voltage becomes less than v th' for the first time is 128. The resistance value at this time may be set as the detection resistance, or the resistance value that provides the previous detection voltage 127 (peak value Vsn-1) may be set as the detection resistance.

In addition, in the above explanation, as shown in FIG. 8, an example was shown in which four detection resistance elements, r+, r2, r5, and r4, are arranged in parallel, but the number is not limited to four, and in general, By configuring a plurality of them, the object of the present invention can be achieved.

FIG. 25 shows another example of the circuit configuration for realizing the present invention, and as shown in the figure, detection resistor elements r1, r2, r5
, r4 are connected to the VDD side, the logic is exactly the same, and there is no change in the effect of the present invention.

As explained above, according to the present invention, since the detection resistor is logically set inside the device, there is no need for an external resistor, thus meeting the demands for smaller, thinner, and lower cost watches. I can do it.

Furthermore, even if the detected current varies due to variations in the step motor, as long as there is a relative difference between the detected current waveform during rotation and the detected current waveform during non-rotation,
It is possible to determine whether the rotor is rotating or not. Therefore, the effect on mass production is extremely large in the sense of absorbing variations during mass production.

Furthermore, one 10 can be applied to integral stator type step motors of all specifications, contributing to standardization with zero labor.

As described above, the present invention only requires the addition of a small number of digital circuits, and there is no other factor that could increase the cost, and its effects are very large.

[Brief explanation of the drawing]

Figure 1 (') is a diagram showing the pulse waveform applied to the coil. Figure 2. Figure 6 (σ) and (b) are diagrams explaining the operation of a step motor. Figure 4 is a conventional drive circuit and detection circuit. Figure 5 . In Fig. 6, (a) shows a detected current waveform and (b) shows a detected voltage waveform. Fig. 7 is a block diagram showing a configuration example of the present invention. Fig. 8 shows an embodiment of the present invention. Circuit configuration diagram. Figure 9 is a circuit diagram for setting the detection resistor. Figure 10 is a timing diagram of Figure 8. Figure 11 is a diagram showing a magnetic hysterin curve. 12th, 1st, 14th, 15th, 16,17゜1(,19,
FIG. 20 is an explanatory diagram of the operation of the step motor. FIGS. 21(a) and 21(b) are diagrams showing current waveforms flowing through the coil due to the P1 pulse. FIG. 22 is a diagram showing fluctuations in the detected voltage waveform. FIG. 23 is a diagram showing a detected voltage waveform obtained by detecting pulses in interval A' for two days. FIG. 24 is a diagram showing fluctuations in the detected voltage waveform. FIG. 25 shows another example of circuit configuration for realizing the present invention. 1... Drive pulse 2... Detection pulse 5...
・Correction pulse 4... Loaf 5... Stator
6. Inner notch 7... Outer notch 4
0...Coil 2nd Applicant Suwa Seikosha Co., Ltd. Agent Patent Attorney 36 Total No. 11 Figure 1λ Figure 13 Red Ceramic Figure
Sphere IS diagram 164th (q diagram C!>e 1718 diagram 20th prisoner

Claims (1)

[Claims] It has a step motor composed of at least a stator, a rotor, and a coil, and determines whether the rotor is rotating or non-rotating by converting the value of a detection current passed through the coil into a voltage generated in a detection resistor, and the detection In an analog electronic clock configured such that the resistance value of the resistor can be set logically, the detection resistor has a plurality of resistor elements arranged in parallel, and each of the resistor elements is connected in series. An analog electronic timepiece characterized by comprising a switching element.