JP2012002533A - Electronic watch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent energy loss due to lack of debate on proper application time, shape, or output and discontinuance timing of a lock pulse, as a 16 ms full pulse is uniformly applied in prior art on basis of an idea that a lock pulse having an adequately large pulse is a satisfactory lock pulse.SOLUTION: An impact discriminating circuit 115 discriminates a level of an impact detected by an impact detecting circuit 114, and a lock pulse of which level is suited to the level of the impact is generated. This enables to reduce electric power consumption compared to prior art while maintaining braking force with reliability equal to or higher than in prior art. Further, electric current consumption due to the lock pulse is reduced by shaping the lock pulse in a comb-teeth-shape (chopper changing), which in prior art has a full pulse shape only.

Description

  The present invention is an electronic timepiece having an impact detection circuit that detects an impact by detecting an impact back electromotive voltage due to an external impact and instructs the pulse shaping circuit to output a lock pulse for braking rotor rotation due to the impact. About.

Electronic wristwatches have traditionally been required to be smaller and with lower power consumption, but recently there has been a strong demand for lower power consumption, especially because of the widespread use of charging power sources that use solar cells. Has come to be.
As one means for reducing the power consumption, it is often performed to reduce the power consumption of the motor by reducing the holding power of the rotor used in the motor. However, this method has a problem in that a large pointer with a single weight cannot be attached and the pointer becomes thin, and visibility is lowered.

In the motor as described above, for example, if the second hand is made thick in order to improve the visibility, the second hand becomes heavy, and there is a concern that the impact resistance may be deteriorated such that the time is distorted only by receiving a small impact.
In order to improve such impact resistance, the holding power of the stepping motor, which is a driving power source, may be increased. However, as described above, the current consumption during driving increases and cannot be adopted.

Therefore, it has been considered to detect the occurrence of impact by detecting the back electromotive current (voltage) waveform generated in the coil of the step motor due to the vibration of the rotor of the step motor caused by the impact, and brake the rotor. .
For example, the following Patent Documents 1 and 2 are disclosed as mechanisms for eliminating the time lag when an external impact is applied. The technique disclosed in Patent Document 1 is to prevent a time lag by braking the rotor of a step motor when it detects a back electromotive force during vibration due to an impact. Hereinafter, this method is simply referred to as an electromagnetic braking method. The technique disclosed in Patent Document 2 makes it easy to detect an impact by periodically amplifying the counter electromotive force at the time of impact detection and the back electromotive force level.

JP 2005-172777 A Japanese Examined Patent Publication No. 61-61356

  The prior art disclosed in Patent Document 1 will be briefly described with reference to FIGS. FIG. 7 is a block diagram showing the configuration of the conventional example, and FIG. 8 is a waveform diagram output from the conventional electronic timepiece. In FIG. 7, 1 is a step motor composed of a rotor 10 and a coil 13, 101 is a drive pulse generating circuit for generating a drive pulse Pa for driving the step motor 1, and 102 is a rotor 10 when an impact is applied to the step motor 1. A lock pulse generation circuit for generating a lock pulse PL for braking control, 103 a pulse selection circuit for selecting a drive pulse Pa generated by the drive pulse generation circuit 101 or a lock pulse PL generated by the lock pulse generation circuit 102; Reference numeral 108 denotes a driver circuit that outputs a pulse selected by the pulse selection circuit 103 to the coil 13, and reference numeral 104 denotes an impact detection circuit that detects the presence or absence of an impact by a counter electromotive current generated in the coil 13 due to vibration of the rotor 10.

Next, circuit operation will be described. As shown in FIG. 8, the drive pulse Pa output from the drive pulse generation circuit 101 at the timing s1 of the second is output from O1 of the coil 13 via the pulse selection circuit 103 and the driver circuit 108, and the rotor 10 is rotated 180 degrees. Rotate. A fixed period during which the vibration of the rotor 10 due to driving is estimated to be settled is provided as a dead period T1 in which no impact detection is performed, and then the process proceeds to an impact detection period T2 in which an impact is detected. In the impact detection period T2, the impact detection circuit 104 periodically detects the back electromotive force due to the impact using the impact detection signal g. When a back electromotive force is generated by the shock G within the period of the shock detection period T2, the shock detection circuit 104 controls the lock pulse generation circuit 102 and the pulse selection circuit 103 so as to immediately output the lock pulse PL. Then, the rotor 10 is brake-controlled by the lock pulse PL output from O1 of the coil 13. After the lock pulse PL is output, a dead time period T1 in which vibration due to the lock pulse PL is settled is provided, and then the process proceeds to an impact detection period T2 in which an impact is detected again.

  The lock pulse PL is output as a full pulse.

  The lock pulse PL is output in the same phase (O1) as the drive pulse Pa. Usually, since the rotor 10 is rotated 180 degrees by the drive pulse Pa, the lock pulse PL output thereafter is output in a phase where the rotor 10 does not rotate.

  However, in the above-described prior art, one type of full pulse lock pulse PL is used for impact. Therefore, there has been a problem that power consumption increases. Specifically, the following was a problem.

(1) Fixed lock pulse The watch does not always have a constant impact. Impacts of various strengths can occur, from weak impacts that touch the body a little while wearing, to strong impacts when accidentally dropped on a hard floor during wearing. When it is going to respond to these various impacts with a fixed lock pulse, it must be set to a lock pulse that can cope with the assumed maximum strength impact. For this reason, a lock pulse PL having a large braking force capable of dealing with the strongest impact is output even during a weak impact, and very wasteful power consumption is consumed.

(2) Lock pulse is full pulse The lock pulse PL requires a large braking force at the beginning of braking, and no braking force is required in the latter half of the period when the rotor vibration has subsided, resulting in wasted power consumption. Was supposed to be.

  In order to eliminate the above-mentioned problems caused by the prior art, the present invention reduces the loss of current consumption in the conventional electromagnetic braking system by changing the size and shape of the lock pulse PL according to the strength of the impact. With the goal.

  In order to solve the above problems and achieve the object, the analog electronic timepiece according to the invention of claim 1 is characterized in that the magnitude of impact is determined and the magnitude and shape of the lock pulse PL are changed.

  An analog electronic timepiece according to a second aspect of the invention is characterized in that the strength of external impact strength is discriminated by a back electromotive voltage value.

The analog electronic timepiece according to the invention of claim 3 is characterized in that the strength of the external impact strength is detected by the time from when the impact occurs until the impact back electromotive voltage exceeds the threshold value.

  In addition, the braking ability is changed by changing the width and shape of the execution pulse.

  The analog electronic timepiece according to the present invention has an effect of minimizing the current consumption due to the lock pulse PL generated when an external impact is applied. In particular, even when the capacity of the battery is reduced, it is possible to prevent time deviation at the time of impact.

It is a block diagram which shows the electronic timepiece circuit structure of Example 1 of this invention. It is an output waveform diagram of the electronic timepiece circuit according to the first embodiment of the present invention. It is a flowchart figure which shows the electronic timepiece operation | movement of Example 1 of this invention. It is an output waveform figure of the electronic timepiece circuit of Example 2 of this invention. It is a flowchart figure which shows the electronic timepiece operation | movement of Example 2 of this invention. It is a figure of various lock pulses which enable low current consumption. (Example 3) It is a block diagram which shows the circuit structure of the conventional electronic timepiece. It is a wave form diagram explaining operation | movement of the circuit of the conventional electronic timepiece. It is a block diagram which shows the circuit structure of the impact discrimination | determination circuit of Example 1 of this invention. It is the determination table in the impact determination circuit of Example 1 of this invention. It is a block diagram which shows the circuit structure of the impact determination circuit of Example 2 of this invention. It is the determination table in the impact determination circuit of Example 2 of the present invention. It is a block diagram which shows the detection method of the impact of Example 3 of this invention.

  Exemplary embodiments of an analog electronic timepiece according to the invention will be described below in detail with reference to the accompanying drawings.

[Example 1: Distinguishing magnitude of impact by magnitude of back electromotive force]
Embodiment 1 of the present invention will be described below in detail with reference to the drawings.
In the first embodiment, the magnitude of the impact is determined based on the magnitude of the counter electromotive voltage generated by the impact, and the optimum lock pulse is selected.
1 is a block diagram showing a circuit configuration of an electronic timepiece according to the first embodiment, FIG. 2 is a waveform diagram output from the electronic timepiece according to the first embodiment, and FIG. 3 is a flowchart showing an operation of the circuit of the electronic timepiece according to the first embodiment. It is. In addition, the same number is attached | subjected to the same component as what was demonstrated in the prior art example, and description is abbreviate | omitted.
FIG. 1 is also used as appropriate in Example 2 and later described below.

In FIG. 1, 1 is a step motor composed of a rotor 10 and a coil 13, 111 is a normal drive pulse generating circuit that generates a normal drive pulse Ps, and 112 is a correction drive pulse that is output when the normal drive pulse Ps cannot be driven. A correction drive pulse generating circuit for generating Pf, and a lock pulse generating circuit for generating a lock pulse PL.
The lock pulse generation circuit 102 is configured to be able to output a strong impact lock pulse PL1, a medium impact lock pulse PL2, and a weak impact lock pulse PL3. Respectively, the braking force is configured to satisfy PL1>PL2> PL3, and the power consumption is configured to satisfy PL1>PL2> PL3 at the same time.
In the first embodiment, the medium impact lock pulse PL2 is not used.

A pulse selection circuit 113 selects one of the normal drive pulse Ps generated by the normal drive generation circuit 111, the correction drive pulse Pf generated by the correction drive pulse generation circuit 112, or the lock pulse PL generated by the lock pulse generation circuit 102. It is.
Reference numeral 108 denotes a driver circuit that outputs the pulse selected by the pulse selection circuit 113 to the coil 13. Reference numeral 114 denotes an impact detection circuit that detects the presence or absence of an impact by a counter electromotive current generated in the coil 13 due to vibration of the rotor 10. Reference numeral 115 denotes a result of 114. Is an impact force determination circuit that determines the type of the lock pulse PL.

Next, the circuit operation will be described with reference to FIGS. As shown in FIG. 2, the height of the impact back electromotive force varies depending on the magnitude of the impact.
That is, the peak value of the heavy impact waveform G1 generated by a very large impact is higher than the peak value of the light impact waveform G3 generated by a light impact.
Therefore, the peak value of the light impact waveform G3 is higher than the threshold value F1, but never higher than the threshold value F2 higher than the threshold value F1. On the other hand, the peak value of the heavy impact waveform G1 is higher than the threshold value F2 (which is naturally higher than the threshold value F1).
By utilizing this fact, it is possible to determine the magnitude of the impact by comparing with a predetermined voltage value (F1 and F2 in FIG. 2).
Therefore, a plurality of voltage thresholds for determining the magnitude of the impact back electromotive force are prepared, and the magnitude of the impact is determined by the impact force determination circuit 115.

FIG. 9 is a block diagram illustrating details of the impact force determination circuit 115 according to the first embodiment. Reference numerals 120 and 121 denote comparators that compare the output S3 of the impact detection circuit 114, that is, the signals S1 and S2 of the back electromotive voltage waveform generated in the coil 1, with a predetermined threshold value.
120 is a comparator for detecting the light impact waveform G3, and compares S3 with the threshold value F1. Reference numeral 121 denotes a comparator for detecting the heavy impact waveform G1, and compares S3 with the threshold value F2. Both the comparators 120 and 121 output signals indicating that they are detected when the threshold values F1 and F2 are exceeded. The comparators 120 and 121 can be constituted by, for example, a known comparator.

A determination circuit 122 determines the presence / absence and magnitude of an impact based on the signals from the comparators 120 and 121, and outputs the result to the lock pulse generation circuit 102 to indicate the magnitude of the lock pulse PL.
In the determination circuit 122, a determination table 123 shown in FIG. 10 is composed of, for example, a ROM, and the determination is made based on the determination table 123.
Further, the determination circuit 122 has an elapsed time counter 124, which is responsible for time monitoring in the detection of SF1 and SF2.

If the back electromotive force voltage exceeds the threshold value F1 and does not exceed the threshold value F2 after a certain time, it is determined as a light impact G3, and the impact force determination circuit 115 outputs the weak lock pulse PL3 to the lock pulse generation circuit 102. The lock pulse generation circuit 102 outputs the weak lock pulse PL3.
When the impact back electromotive voltage exceeds the threshold value F1 and the threshold value F2, it is determined as a heavy impact G1, and the impact force determination circuit 115 instructs the lock pulse generation circuit 102 to output the strong lock pulse PL1, and the lock pulse generation circuit 102 Outputs a strong lock pulse PL1.

  As described above, the lock pulses PL1 and PL3 are configured such that the braking force is PL1> PL3 and the power consumption is simultaneously PL1> PL3. As shown in FIG. 2, the first embodiment is realized by changing the pulse widths of PL1 and PL3.

Then, the lock pulse PL in each case is output from the terminal O1 of the driver circuit 108 via the pulse selection circuit 113, brakes the rotor 10, and prevents the rotor 10 from being rotated by an impact.
If the impact counter electromotive voltage does not detect the threshold value F1 and the threshold value F2, it is determined that no impact is detected, and no lock pulse is output.

  The above operation will be described with reference to the flowchart of FIG. First, after the end of the normal hand movement, the impact is detected by the impact detection circuit 114 (step ST11). Specifically, it is determined whether an impact exceeding the threshold F1 is detected by the impact force determination circuit 115 during the impact detection section T2 shown in FIG. If no impact exceeding the threshold F1 is detected within a predetermined time, specifically during the impact detection section T2 (N in step ST12), no impact is detected, so no lock pulse is output, The impact detection process ends.

  If there is an impact (Y in step ST12), the impact magnitude discrimination circuit 115 discriminates the magnitude of the impact based on the presence or absence of the F2 signal in order to determine whether the impact is a heavy impact or a light impact. (Step ST13). If both SF1 and SF2 signals are generated (Y in step ST13), it is determined as a heavy impact G1 (G1 in the determination table 1), and a large lock pulse PL1 is generated.

  If SF2 is not detected within a predetermined time (for example, during the impact detection section T2) and only the SF1 signal is detected (N in step ST13), it is determined as light impact G3 (determination table 1 G3) A small lock pulse PL3 is output.

<Effect of Example 1>
The first embodiment has the following effects.
(1) The light shock G3 and the heavy shock G1 are discriminated based on the magnitude of the back electromotive force caused by the shock, and a lock pulse of a braking force corresponding to each shock can be output.
Therefore, it is possible to reduce the power consumption as compared with the prior art while maintaining a reliable braking force equal to or higher than that of the prior art.
(2) The discrimination between the light impact G3 and the heavy impact G1 can be realized with a simple circuit configuration such as a known level of comparator, table reference, and time monitoring by a counter.
Therefore, the present embodiment can be implemented without significant change from the conventional circuit.

<Modification of Example 1>
The above-described configuration of the first embodiment is an example, and can be appropriately changed without departing from the gist of the invention. For example, it is as follows.
(1) The values of the threshold values F1 and F2 do not need to be fixed values, but rather should be changed and set as appropriate depending on the configuration of the motor 1 and the display body (pointer) attached. The same applies to the pulse widths of the lock pulses PL1 and PL3.

(2) The configurations of the comparators 120 and 121 and the determination circuit 122 may be any configuration as long as their roles can be achieved.
For example, the determination table 123 may also be configured with a gate as well as a ROM.
The comparators 120 and 121 may also be inverters in which Vth is set to F1 and F2 as long as the thresholds F1 and F2 are fixed. In this way, the comparators 120 and 121 can be made small.

(3) Although the determination time at ST14 in the flowchart of FIG. 3 is the impact detection interval T2, the presence or absence of the heavy impact G1 can be determined at an earlier time. good. In this way, since the response to the light impact G3 can be made at an early stage, more reliable braking is possible.

(4) Similarly, the determination by ST14 in the flowchart of FIG. 3 may be performed not by time but by redetection of SF1. That is, when the back electromotive force waveform falls below without detecting SF2, it can be determined as light impact G3. It is more certain if used in combination with time determination.

(5) The method of changing the braking force and power consumption of the lock pulses PL1, PL3 is not limited to the pulse width. Details of this will be described in an embodiment described later.

(6) The power consumption of the comparators 120 and 121 can be further reduced by turning on the power only during the period used for detection. It is particularly advantageous when the comparator is made of a comparator.

(7) In the first embodiment, two comparators 120 and 121 are prepared. First, a threshold value to be compared is set to F1, and after F1 is detected, the threshold value to be compared is changed to F2 to detect F2. One comparator can also be implemented.
In this way, a single comparator, which becomes a large circuit when integrated into an IC, is sufficient, and this contributes to miniaturization of the circuit.

(8) In the first embodiment, two threshold values F1 and F2 are prepared, but any number of threshold values can be implemented. As the number of thresholds increases, a fine lock pulse PL can be set, which contributes to further lower power consumption.

[Example 2: Detecting the magnitude of impact detection based on the time until detection of a predetermined counter electromotive voltage value]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. In the second embodiment, the magnitude of the external impact is determined based on the length of time from when the impact occurs until the back electromotive force exceeds the threshold value F0, and an optimum lock pulse is selected.

As shown in FIG. 4, the rising slope of the back electromotive force waveform due to impact varies depending on the strength of the impact (the stronger the impact, the steeper the slope). That is, the rising slope of the heavy impact waveform G1 generated by a very large impact is a waveform of the light impact waveform G3 generated by a light impact or the middle impact waveform G2 generated by an intermediate impact between the heavy impact G1 and the light impact G3. It becomes larger than the rising. Accordingly, the time from when the impact occurs to 0 and the time when the impact back electromotive voltage reaches the threshold value F0 becomes shorter as the impact increases.
By utilizing this, the magnitude of the impact can be determined by comparing the time (t1 and t2 in FIG. 4) until the predetermined voltage threshold is exceeded.

The difference between the second embodiment and the first embodiment is the determination method in the impact force determination circuit 115.
FIG. 11 is a block configuration diagram illustrating details of the impact determination circuit 115 in the second embodiment. A comparator 130 compares the output S3 of the impact detection circuit 114 with the threshold value F0. The comparator 130 outputs a signal indicating that it has been detected when the threshold value F0 is exceeded. 130 can be constituted by a known comparator, for example.
Reference numeral 131 denotes an elapsed time counter that performs time monitoring from the time of impact occurrence until F0 detection. Further, the magnitude of impact is determined based on a signal from the counter 131 by a determination table 132 shown in FIG.

If the time t until the threshold value F0 is exceeded after the impact is t1 or less, it is determined as the heavy impact G1, and the impact force determination circuit 115 instructs the lock pulse generation circuit 102 to output the heavy impact lock pulse PL1, The lock pulse generation circuit 102 outputs a heavy impact lock pulse PL1.
Further, if the time until the threshold value F0 is exceeded after the impact is t2 or more, it is determined as a light impact G3, and the impact force determination circuit 115 instructs the lock pulse generation circuit 102 to output the light shock lock pulse PL3. The lock pulse generation circuit 102 outputs a light shock lock pulse PL3.
If the time t until the threshold value F0 is exceeded after the impact is t1 or more and t2 or less, it is determined as the middle impact G2 between the heavy impact G1 and the light impact G3, and the impact force determination circuit 115 generates the lock pulse. The circuit 102 is instructed to output the medium shock lock pulse PL2, and the lock pulse generation circuit 102 outputs the medium shock lock pulse PL2.

  As described above, the lock pulses PL1, PL2, and PL3 are configured such that the braking force is PL1> PL2> PL3 and the power consumption is simultaneously PL1> PL2> PL3. As shown in FIG. 4, the present embodiment is realized by changing the pulse widths of PL1, PL2, and PL3.

Then, the lock pulse PL in each case is output from the terminal O1 of the driver circuit 108 via the pulse selection circuit 113, brakes the rotor 10, and prevents the rotor 10 from being rotated by an impact.
When the impact back electromotive voltage does not detect the threshold value F0, it is determined that the impact is not detected, and the lock pulse is not output.

  The above operation will be described with reference to the flowchart of FIG. First, after the end of normal hand movement, the impact detection circuit 114 detects impact (step ST21). Specifically, it is detected whether or not an impact exceeding the threshold value F0 is detected by the impact force determination circuit 115 during the impact detection section T2 shown in FIG. If no impact exceeding the threshold value F0 is detected within a predetermined time, specifically during the impact detection section T2 (N in step ST22), no impact is detected, so no lock pulse is output, The impact detection process ends.

  If there is an impact (Y in step ST22), in order to determine whether the impact is a heavy impact or a light impact, a process until the impact level exceeds the threshold F0 by the impact force discrimination circuit 115 is determined. The time is discriminated (step ST22). If the time t exceeding the threshold value F0 is equal to or less than t1 (Y in step ST23), it is determined as a heavy impact G1 (G1 in the determination table 2), and a heavy impact lock pulse PL1 is generated.

  When the time t exceeding the threshold value F0 is equal to or greater than t2 (N in step ST24), it is determined as a light impact G3 (G3 in the determination table 2), and a light shock lock pulse PL3 is generated.

  When the time t exceeding the threshold value F0 is t1 or more and t2 or less (Y of step ST24), it is determined that the impact is G2 (G2 of the determination table 2), and intermediate between the heavy impact lock pulse PL1 and the light impact lock pulse G2. The middle-impact lock pulse LP2 positioned at is output.

<Effect of Example 2>
The second embodiment has the following effects.
(1) Light shock G3, medium shock G2, and heavy shock G1 are determined by the time from when the shock occurs until the counter electromotive voltage resulting from the shock exceeds the threshold value F0, and the lock pulse PL of the braking force corresponding to each shock is determined. It becomes possible to output.
Therefore, it is possible to reduce the power consumption as compared with the prior art while maintaining a reliable braking force equal to or higher than that of the prior art.
(2) The light impact G3, the medium impact G2, and the heavy impact G1 can be distinguished by a simple circuit configuration such as time monitoring by a known level counter and table reference.
Therefore, this embodiment can be carried out without significant change from the conventional circuit.
(3) Several types of impacts such as a light impact G3, a medium impact G2, and a heavy impact G1 can be discriminated by providing one threshold value without providing a plurality of threshold values. Therefore, it contributes to miniaturization of the circuit.

<Modification of Example 2>
The configuration of the above-described second embodiment is an example, and can be appropriately changed without departing from the gist of the invention. For example:
(1) In the second embodiment, two determination reference times t1 and t2 are prepared for determining the light impact G3, the medium impact G2, and the heavy impact G1, but any number of determination reference times may be set. As the number of determination reference times set increases, the resolution for determining the magnitude of impact increases, and it becomes possible to set a lock pulse PL having a braking force corresponding to each impact in detail, thereby contributing to further lower power consumption.

(2) Although the threshold value for detecting the back electromotive force voltage is prepared as one F0 in the second embodiment, there may be a plurality of threshold values.

(3) The configuration of the comparator 130, the counter 131, and the determination table 132 may be any configuration as long as the role can be achieved.
For example, the determination table 132 may also be configured with a gate as well as a ROM. The comparator 130 may also be an inverter in which Vth is set to F0 as long as the threshold value F0 is fixed. In this way, the comparator 130 can be made small.

(4) The determination at ST23 and ST24 in the flowchart of FIG. 5 may be performed not based on the time from the first impact until F0 detection but on the time from F0 detection to F0 re-detection.

(5) The method of changing the braking force and power consumption of the lock pulses PL1, PL2, and PL3 is not limited to the pulse width. Details of this will be described in an embodiment described later.

(6) The comparator 130 can be further reduced in power consumption if it is turned on only during the period used for detection.

[Example 3: Making braking capacity variable by lock pulse width and lock pulse shape]
Next, a third embodiment of the present invention will be described in detail with reference to FIGS.
The third embodiment is an example in which the braking ability of the lock pulse PL is changed by changing the effective pulse width and shape, or the timing of generation / canceling of the lock pulse PL, thereby reducing the power consumption.

(3-1) Abort Determination by Zero-Cross Detection As shown in FIG. 6A, the point where the back electromotive force generated in the motor becomes zero (point P in FIG. 6) is called the zero-cross point. Normally, a large driving force is not required after this zero cross point. Therefore, by detecting this zero cross point and stopping the output of the lock pulse after a predetermined time, the power consumption due to the lock pulse can be kept low.

  FIG. 13 is a system configuration diagram of this embodiment. The difference from FIG. 1 is that the driver circuit 108 has a zero-cross detection circuit 160. The zero-cross detection circuit 160 is a known technique found in, for example, Japanese Patent No. 3645908, and a detailed description thereof is omitted.

  The zero-cross detection circuit 160 starts detection of the zero-cross point P after the output of the lock pulse PL0 is started, and outputs a zero-cross point detection signal P0 to the lock pulse generation circuit 102 when the zero-cross point P is detected. Receiving the zero-cross point detection signal P0, the lock pulse generation circuit 102 stops the lock pulse PL0 after elapse of a predetermined time appropriately determined from motor characteristics and the like.

  As described above, the variable width control of the lock pulse PL0, which has been a fixed width until now, becomes possible, and it is not necessary to output a large lock pulse PL0 unnecessarily, so that power consumption can be kept low.

(3-2) Change of Duty Using a chopped pulse instead of a full pulse in order to reduce power consumption in the motor drive pulse is a well-known technique that can be said to be well-known. In this embodiment, this known technique is applied to a lock pulse, and further power consumption is reduced.

When an impact is applied to the timepiece and the rotor is vibrated, a back electromotive current is generated as shown in FIG. 6 due to the vibration of the rotor, and a lock pulse PLC is generated.
As shown in FIG. 6B, the lock pulse PLC is output as a chopped pulse of a predetermined duty.
Here, when a certain amount of time (approximately several milliseconds later) elapses after the output of the lock pulse PLC, the vibration of the rotor is considerably reduced. In other words, the energy of the lock pulse PLC required for rotor braking at the time of impact becomes redundant because the rotor vibration starts to settle after several milliseconds. Therefore, after the generation of the lock pulse PLC, the duty of the lock pulse PLC is output as a pulse smaller than the duty after the start of output in accordance with the time when the rotor vibration starts to subside. Thereby, it is possible to reduce surplus energy due to the lock pulse PLC and to further reduce power consumption.

(3-3) Current Limit by Built-in Resistor In addition to changing the duty as a current limit method, as shown in FIG. 6 (c), the resistor and the coil 13 mounted in the watch according to the time when the rotor vibration starts to settle. Are switched so as to be connected in series, so that excess energy due to the lock pulse PLC may be reduced.
In addition to mounting on the circuit board, the resistor may be built in the IC.

<Effect of Example 3>
The third embodiment has the following effects.
(1) Conventionally, the width of the lock pulse PL is set to be long, and there are many cases where the specification is excessive with respect to the shaking of the rotor due to impact. By stopping the lock pulse PL after a certain period of time after the back electromotive force voltage has passed the zero value, it is possible to achieve lower power consumption than before while maintaining the same or more reliable braking force. is there.

(2) By making the lock pulse shape a comb tooth (chop), it is possible to reduce the power consumption as compared with the prior art while maintaining a reliable braking force equal to or higher than the conventional one.

(3) After the rotor shake due to impact has been damped by the lock pulse PL, it is possible to reduce the amount of excess current flowing in the coil by the lock pulse PL by using a resistor, thereby reducing the power consumption compared to the conventional case. .

<Modification of Example 3>
The configuration of the above-described third embodiment is an example, and can be changed as appropriate without departing from the spirit of the invention. For example:
(1) The timing of stopping the lock pulse PL0 is not only based on the time when the back electromotive force value passes the zero point, but may be changed and set as appropriate depending on the motor configuration and the display body (pointer) attached. .

(2) A coil for detecting zero crossing may be provided in addition to the coil for outputting the drive pulse and the lock pulse PL.

(3) The truncation by zero cross and the chopper of the lock pulse do not have to be used independently. These may be used together.
For example, the duty may be reduced or a built-in resistor may be connected after zero-cross detection (from a predetermined time).
In this way, more effective low power consumption can be realized.

(4) When the lock pulse PL is in the form of a comb (chop), the entire pulse need not be in the form of a comb. The lock pulse PL is divided into a plurality of stages, such as a front stage, a rear stage, a front stage, a middle stage, and a rear stage, and a full pulse or a comb-like pulse is assigned to each of them to balance the braking ability and the power consumption.

(5) Example 3 may be combined with Example 1 or Example 2. In this way, more effective low power consumption can be realized.

DESCRIPTION OF SYMBOLS 1 Step motor 10 Rotor 11 Magnet 12 Stator 13 Coil 101 Drive pulse generation circuit 102 Lock pulse generation circuit 111 Normal drive pulse generation circuit 103, 113 Pulse selection circuit 108 Driver circuit 104, 114 Impact detection circuit 115 Impact force discrimination circuit Pa Drive pulse Ps Normal drive pulse Pf Correction pulse PL Lock pulse S1, S2 Shock signal

Claims (4)

A step motor composed of a rotor and a coil;
A motor driver for driving the step motor;
A reference signal generation circuit for outputting various timing signals;
Receiving various timing signals output from the reference signal generation circuit,
Create various pulse signals to drive the step motor,
A pulse shaping circuit for outputting to the motor driver;
The pulse shaping so as to detect a shock by detecting a back electromotive voltage (hereinafter referred to as a shock back electromotive voltage) caused by vibration of the rotor due to an external shock, and to output a lock pulse for braking the rotor rotation due to the shock. An impact detection circuit for instructing the circuit;
In an electronic watch having
The pulse shaping circuit is
It is configured to be able to output multiple types of lock pulses with different braking capabilities,
The impact detection circuit is configured to be able to detect the strength of an external impact in a plurality of stages,
Select a lock pulse that matches the detected impact strength,
An electronic timepiece instructing output to the pulse shaping circuit. The impact detection circuit includes:
The electronic timepiece according to claim 1, wherein the external impact strength in a plurality of stages is discriminated based on the level of impact back electromotive force. The impact detection circuit includes:
Multi-stage external impact strength
2. The electronic timepiece according to claim 1, wherein the electronic timepiece is determined based on a time from the start of detection of the shock back electromotive force voltage to detection of a predetermined back electromotive voltage value. The pulse shaping circuit is
The electronic timepiece according to any one of claims 1 to 3, wherein the braking ability of a plurality of types of lock pulses is changed according to an effective pulse width.