JP2009288133A - Stepping motor control circuit and analog electronic timepiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform more accurate rotation detection without elongating a vibration attenuation time of a motor, and without enlarging a detection element. <P>SOLUTION: During a rotation driving period, a switch control circuit 303 puts transistors Q2, Q3 simultaneously into the ON-state, or puts transistors Q1, Q4 simultaneously into the ON-state to supply a current to a coil 209 in the normal direction or in the reverse direction, and thereby a stepping motor is driven rotatively. When detecting a detection signal generated in the stepping motor during a rotation detection period, the switch control circuit 303 performs ON/OFF control of the transistor Q4 with a prescribed period in the state where transistors Q3, Q6 are put into the ON-state, or performs ON/OFF control of the transistor Q3 with a prescribed period in the state where transistors Q4, Q5 are put into the ON-state, to thereby make detection by a comparator 304. In this case, during a prescribed period in the rotation detection period, rotation detection operation is performed with a shorter period than other periods. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a stepping motor control circuit and an analog electronic timepiece using the stepping motor control circuit.

  2. Description of the Related Art Conventionally, a stator having a rotor housing hole and a positioning portion for determining a stop position of the rotor, a rotor disposed in the rotor housing hole, and a coil, and supplying an alternating signal to the coil to supply the stator A stepping motor that rotates the rotor by generating a magnetic flux and stops the rotor at a position corresponding to the positioning portion is used in an analog electronic timepiece or the like.

  As a control method of the stepping motor, when the stepping motor is driven by a main drive pulse, it detects whether or not it has rotated by detecting a detection signal based on a detection signal that is an induced voltage generated in the stepping motor, Depending on whether it has rotated or not, it is driven by changing to a main drive pulse with a different pulse width, or a correction drive system is used that forcibly rotates with a correction drive pulse having a pulse width larger than the main drive pulse. (For example, refer to Patent Document 1).

  Further, the correction driving method described in Patent Document 2 is provided with means for comparing and determining the detection time with the reference time in addition to the detection of the induced voltage in Patent Document 1, and after rotating the rotor with the main drive pulse P11, ( 1) When the detected voltage falls below Vcomp, a correction drive pulse P2 is output to rotate, and the next main drive pulse P1 outputs a main drive pulse P12 having a larger energy than the main drive pulse P11 to rotate (2 ) If the detection time when rotating with the main drive pulse P12 is earlier than the reference time, the main drive pulse P12 is controlled to rank down to the main drive pulse P11.

The rotation determination method in the invention described in Patent Document 1 determines whether or not to rotate depending on whether or not the induced voltage exceeds a predetermined reference threshold value.
Further, in the invention described in Patent Document 2, in addition to the rotation discrimination method described in Patent Document 1, in consideration of at which point in the rotation detection period an induced voltage exceeding a predetermined reference threshold is generated, the rotation margin is considered. The rotational drive is controlled by distinguishing the degree.
In both cases, detection is performed using periodic rotation detection pulses at regular intervals within the rotation detection period, and only periodic detection can be performed at regular intervals. You may miss it.

If the detection pulse cycle is shortened and the rotation detection cycle is shortened, the closed loop time after the detection pulse is cut off is shortened, so the vibration attenuation time is naturally increased, and the rotation attenuation of the rotor does not fall within the correction drive pulse output. There is a problem that there is no fear.
Further, although the induced voltage can be increased by increasing the detection resistance that is a detection element for detecting rotation, there is a problem that the size of the integrated circuit (IC) constituting the detection circuit is increased.

Japanese Patent Publication No. 61-15385 WO2005 / 119377

  The present invention has been made in view of the above problems, and an object thereof is to perform more accurate rotation detection without increasing the vibration damping time of the motor and without increasing the detection element.

According to the present invention, in the rotation detection period for detecting the rotation of the stepping motor, the detection signal generated by the rotation of the stepping motor is detected at a predetermined period, and whether or not the detection signal exceeds a predetermined reference threshold value. The rotation detecting means for detecting whether or not the stepping motor has rotated, and the control means for driving and controlling the stepping motor with or without changing the main drive pulse according to the detection result by the rotation detecting means And comprising
A stepping motor control circuit is provided, wherein the rotation detection means detects rotation at a predetermined period in the rotation detection period with a cycle shorter than other periods.
The rotation detection means detects rotation in a predetermined period in the rotation detection period at a cycle shorter than other periods.

  According to the present invention, in the analog electronic timepiece having a stepping motor that rotationally drives the time hand and a stepping motor control circuit that controls the stepping motor, the stepping motor control circuit described above as the stepping motor control circuit An analog electronic timepiece characterized by using is provided.

According to the stepping motor control circuit of the present invention, it is possible to perform more accurate rotation detection without increasing the vibration damping time of the stepping motor and without increasing the detection element.
Further, according to the analog electronic timepiece according to the present invention, it is possible to perform more accurate rotation detection without increasing the vibration attenuation time of the stepping motor and without increasing the detection element. It becomes possible to perform an operation.

Hereinafter, a stepping motor control circuit and an analog electronic timepiece according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals.
FIG. 1 is a block diagram of an analog electronic timepiece using a stepping motor control circuit according to an embodiment of the present invention, and shows an example of an analog electronic wristwatch.

  In FIG. 1, an analog electronic timepiece includes an oscillation circuit 101 that generates a signal of a predetermined frequency, a frequency dividing circuit 102 that divides the signal generated by the oscillation circuit 101 and generates a clock signal that serves as a time reference, and an electronic timepiece. A control circuit 103 that performs control such as control of each electronic circuit element that is configured and drive pulse change control, and a drive pulse selection circuit 104 that selects and outputs a drive pulse for motor rotation driving based on a control signal from the control circuit 103. , A stepping motor 105 that is rotationally driven by the drive pulse from the drive pulse selection circuit 104, and a time hand that is rotationally driven by the stepping motor 105 to display the time (in the example of FIG. 1, three of the hour hand 107, the minute hand 108, and the second hand 109). Rotation detection of the detection signal indicating the rotation state from the analog display unit 106 having the type) and the stepping motor 105 The rotation detection circuit 110 to detect in the period and the detection signal indicating that the stepping motor 105 has rotated are compared with the time at which the rotation detection circuit 110 detects and a plurality of detection sections in the rotation detection period, and which detection signal is detected. It has a detection section discrimination circuit 111 that discriminates whether or not it is detected in a section. As will be described later, the rotation detection period T for detecting whether or not the stepping motor 105 has been rotated is divided into three detection sections T1 to T3.

The rotation detection circuit 110 detects a detection signal that exceeds a predetermined reference threshold value Vcomp when the stepping motor 105 rotates, and the detection signal exceeds the reference threshold value Vcomp when the motor 105 does not rotate. The reference threshold value Vcomp is set so as not to occur.
The oscillation circuit 101 and the frequency dividing circuit 102 constitute signal generating means, and the analog display unit 106 constitutes time display means. The rotation detection circuit 110 constitutes a rotation detection means, and the control circuit 103, the drive pulse selection circuit 104, the rotation detection circuit 110, and the detection section discrimination circuit 111 constitute a control means.

FIG. 2 is a configuration diagram of the stepping motor 105 used in the embodiment of the present invention, and shows an example of a time stepping motor generally used in an analog electronic timepiece.
In FIG. 2, the stepping motor 105 includes a stator 201 having a rotor housing through hole 203, a rotor 202 rotatably disposed in the rotor housing through hole 203, a magnetic core 208 joined to the stator 201, and a winding around the magnetic core 208. A rotated coil 209 is provided. When the stepping motor 105 is used in an analog electronic timepiece, the stator 201 and the magnetic core 208 are fixed to a base plate (not shown) with screws (not shown) and joined to each other. The coil 209 has a first terminal OUT1 and a second terminal OUT2.

The rotor 202 is magnetized to two poles (S pole and N pole). A plurality of (two in this embodiment) notch portions (outer notches) 206 and 207 are provided at positions facing each other across the rotor accommodating through hole 203 at the outer end portion of the stator 201 formed of a magnetic material. Is provided. Saturable portions 210 and 211 are provided between the outer notches 206 and 207 and the rotor accommodating through hole 203.
The saturable portions 210 and 211 are configured not to be magnetically saturated by the magnetic flux of the rotor 202 but to be magnetically saturated when the coil 209 is excited to increase the magnetic resistance. The through hole 203 for accommodating the rotor has a circular hole shape in which a plurality of (two in the present embodiment) half-moon-shaped notches (inner notches) 204 and 205 are integrally formed at the opposing portion of the through hole having a circular outline. It is configured.

The notches 204 and 205 constitute a positioning part for determining the stop position of the rotor 202. In a state where the coil 209 is not excited, the rotor 202 has a position corresponding to the positioning portion as shown in FIG. 2, in other words, a line segment connecting the notches 204 and 205 with the magnetic pole axis of the rotor 202. It is stably stopped at a position that intersects perpendicularly (a position that forms an angle θ0 with the direction X of the magnetic flux flowing through the stator 201).
Now, a rectangular-wave drive pulse is supplied from the drive pulse selection circuit 104 between the terminals OUT1 and OUT2 of the coil 209 (for example, the first terminal OUT1 side is positive and the second terminal OUT2 side is negative), and the arrow in FIG. When a current i flows in the direction, a magnetic flux is generated in the stator 201 in the direction of the broken arrow. As a result, the saturable portions 210 and 211 are saturated and the magnetic resistance is increased, and then the rotor 202 is rotated 180 degrees in the direction of the solid arrow in FIG. 2 due to the interaction between the magnetic pole generated in the stator 201 and the magnetic pole of the rotor 202. Rotates and stops stably.

Next, from the drive pulse selection circuit 104, a drive pulse having a reverse polarity rectangular wave is supplied to the terminals OUT1 and OUT2 of the coil 209 (the first terminal OUT1 side is connected to the negative electrode so that the drive polarity is opposite to that of the drive). When the second terminal OUT2 side is the positive electrode) and a current is passed in the direction indicated by the arrow in FIG. As a result, the saturable portions 210 and 211 are first saturated, and then the rotor 202 rotates 180 degrees in the same direction as described above due to the interaction between the magnetic poles generated in the stator 201 and the magnetic poles of the rotor 202, and stably stops. To do.
Thereafter, by supplying signals with different polarities (alternating signals) to the coil 209 in this way, the above operation is repeated, and the rotor 202 can be continuously rotated 180 degrees in the direction of the arrow. It is configured as follows. In the present embodiment, as described later, a plurality of main drive pulses P10 to P1m and correction drive pulses P2 having different energy are used as drive pulses.

FIG. 3 is a circuit diagram showing details of the drive pulse selection circuit 104 and the rotation detection circuit 110.
In FIG. 3, P channel MOS transistors Q1 and Q2, N channel MOS transistors Q3 and Q4, and a switch control circuit 303 are components of the drive pulse selection circuit 104. The source connection point of the transistors Q1 and Q3, the transistor Q2 and the transistor A coil 209 of the stepping motor 105 is connected between the source connection point of Q4.

On the other hand, the detection resistor 301 connected in series to the N-channel MOS transistors Q3 to Q6, the transistor Q5, the detection resistor 302 connected in series to the transistor Q6, the comparator 304, and the switch control circuit 303 are configured in the rotation detection circuit 110. Is an element.
The gates of the transistors Q1 to Q6 are connected to the switch control circuit 303. A connection point OUT2 between the detection resistor 301 and the coil 209 and a connection point OUT1 between the detection resistor 302 and the coil 209 are connected to an input portion of the comparator 304. A predetermined reference threshold value Vcomp (VSS in this embodiment) is input to the input unit of the comparator 304.

The transistor Q3 is a first switch element, the transistor Q1 is a second switch element, the transistor Q4 is a third switch element, the transistor Q2 is a fourth switch element, the transistor Q5 is a fifth switch element, the transistor Q6 is a sixth switch element, The detection resistor 301 constitutes a first detection element, and the detection resistor 302 constitutes a second detection element. The transistor Q5 and the detection resistor 301 constitute a first series circuit, and the transistor Q6 and the detection resistor 302 constitute a second series circuit.
The transistors Q1 to Q4, the switch control circuit 303, and the control circuit 103 constitute the control means. Transistors Q3 to Q6, detection resistors 301 and 302, a comparator 304, a switch control circuit 303 and a control circuit 103 constitute the rotation detection means.

  When the stepping motor 105 is rotationally driven during the rotational drive period during which the stepping motor 105 is rotationally driven, the switch control circuit 303 responds to the rotational drive control pulse from the control circuit 103 and simultaneously turns on the transistors Q2 and Q3. Alternatively, by turning on the transistors Q1 and Q4 at the same time, current is supplied to the coil 209 in the forward direction or the reverse direction, thereby driving the motor 105 to rotate.

In the rotation detection period subsequent to the rotation drive period, the switch control circuit 303 responds to the rotation detection control pulse Vi from the control circuit 103 when detecting a detection signal that is an induced voltage generated in the stepping motor 105 by the rotation drive. Then, by turning on / off the transistor Q4 in a predetermined cycle with the transistors Q3, Q6 turned on, or by turning on / off the transistor Q3 in a predetermined cycle with the transistors Q4, Q5 turned on. , And detected by the comparator 304. The comparator 304 detects a detection signal that exceeds the reference threshold value Vcomp among detection signals that are induced voltages induced in the motor 105 (in other words, the coil 209), and outputs the detection signal to the rotation section determination circuit 111.
The rotation drive control of the motor 105 is performed while alternately repeating the rotation drive period and the rotation detection period.

  In the present embodiment, when detecting a detection signal that is an induced voltage of the motor 105 in the rotation detection period, the switch control circuit 303 is configured to turn on / off the transistors Q3 and Q4 at a plurality of types of cycles, and rotate. The detection period is configured to be different between a predetermined period within the detection period and another period. The predetermined period in the rotation detection period is a period in which an induced voltage exceeding the reference threshold is expected to be generated due to the drive characteristics of the motor, the energy of the main drive pulse to be driven, and the like. As described above, the switch control circuit 303 detects a predetermined period in the rotation detection period at a cycle shorter than other periods.

FIG. 4 is a timing chart in the case where the induced voltage is detected in the rotation detection period T after being driven to rotate by the main drive pulse P10 in the rotation drive period. FIG. 4A is a timing chart showing the detection operation in the present embodiment. FIG. FIG. 2B is a timing chart showing a conventional detection operation, where the detection period is one type and the detection operation is performed at a constant period.
In this embodiment, the rotation detection period T is divided into a plurality (three in this embodiment) of sections T1 to T3, and the transistors Q3 and Q4 are controlled to be turned on / off at a plurality of periods. That is, the switch control circuit 303 performs detection operation by performing on / off control in the first period T1 and the third period T3 in the first period (for example, 1 kHz in terms of frequency), and a detection signal indicating rotation may be generated. In the high second section T2, the rotation detection operation is performed by performing on / off control at a cycle shorter than the first cycle (for example, 2 kHz in terms of frequency).

As shown in FIG. 4, when all the detection intervals T1 to T3 are detected in a single cycle as in the conventional case, a detection signal exceeding the reference threshold value Vcomp is not detected in the detection interval T2.
However, as in the present embodiment, the detection sections T1 and T3, which are unlikely to generate a detection signal exceeding the reference threshold value Vcomp, perform the detection operation in the first period that is long as in the prior art, and the reference threshold value. In the detection period T2 where there is a high possibility that a detection signal exceeding Vcomp is generated, the presence or absence of a detection signal exceeding the reference threshold Vcomp is more reliably detected by performing the detection operation in a second period shorter than the first period. It becomes possible.

By narrowing the detection interval in the important section in the rotation detection period T, the peak of the detection signal can be detected more reliably, so that the rotation detection can be performed more reliably, the detection resistance is increased, and the induced voltage peak is increased. There is no need to increase the value.
Thus, since not all the rotation detection periods T are detected in a short cycle, it is possible to capture the peak of the detection signal without increasing the vibration attenuation time of the stepping motor 105 and without increasing the detection element. As a result, it is possible to perform more accurate rotation detection.

In addition, since it is possible to more accurately determine the rotation detection, it is possible to prevent the main drive pulse P1 from being erroneously ranked up or erroneously driven by the correction drive pulse P2, There are also effects such as energy saving.
In the present embodiment, the rotation detection is performed in a short period in the detection section T2 of the rotation detection period T. However, in the other detection sections T1 and T3, a short period is detected depending on the drive characteristics and load of the motor. You may comprise so that rotation may be detected by.

FIG. 5 shows an operation in the present embodiment when the main drive pulse P1 is changed, is not changed, or is driven by the correction drive pulse P2, depending on in which section the detection signal representing the rotation is detected. It is the table | surface (determination chart) which shows.
As shown in FIG. 4, when the detection signal indicating the rotation is not detected in the first detection section T1 but is detected in the second detection section T2, the control circuit 103 determines that the rotation has a drive energy margin. Thus, regardless of the detection situation in the third detection section T3, the drive pulse is used so that the main drive pulse P1 is driven down by one rank in the next rotation drive without performing the drive by the correction drive pulse P2. The selection circuit 104 is controlled.

When a detection signal representing rotation is detected at least in the first detection section T1 and the second detection section T2, the control circuit 103 determines that the drive energy has no allowance and drives with the correction drive pulse P2. Without performing the above operation, the drive pulse selection circuit 104 is controlled so as to rotate without changing the main drive pulse P1 in the next rotation drive.
When the detection signal representing the rotation is not detected in the second detection interval T2 but is detected in the third detection interval T3, the control circuit 103 drives the drive energy regardless of the detection situation in the first detection interval T1. It is determined that there is a possibility that the rotation cannot be driven next time, and the main drive pulse P1 is increased by one rank in the next rotation drive, and the rotation drive is performed without the drive by the correction drive pulse P2. The drive pulse selection circuit 104 is controlled.

  In addition, when the detection signal indicating the rotation is not detected in the second detection section T2 and the third detection section T3, the control circuit 103 determines that the rotation is not performed regardless of the detection situation in the first detection section T1. Then, after the drive by the correction drive pulse P2, the drive pulse selection circuit 104 is controlled so that the main drive pulse P1 is upgraded by one rank in the next rotation drive.

In the above-described embodiment, the pulse width is changed in order to change the energy of each main drive pulse P1, but the drive energy can also be changed by changing the pulse voltage.
In addition to the time hand, the present invention can be applied to a stepping motor for driving a calendar or the like.
Moreover, although the example of the electronic timepiece has been described as an application example of the stepping motor, it can be applied to an electronic device using the motor.

The stepping motor control circuit according to the present invention is applicable to various electronic devices that use the stepping motor.
The electronic timepiece according to the present invention can be applied to various analog electronic timepieces, including analog electronic timepieces with various calendar functions such as an analog electronic wristwatch with a calendar function and an analog electronic table clock with a calendar function.

1 is a block diagram of an analog electronic timepiece according to an embodiment of the present invention. It is a block diagram of the stepping motor used for the analog electronic timepiece which concerns on embodiment of this invention. It is a partial detailed circuit diagram of the stepping motor control circuit according to the embodiment of the present invention. It is a timing diagram of the stepping motor control circuit which concerns on embodiment of this invention. It is a determination chart explaining operation | movement of the stepping motor control circuit which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Oscillator 102 ... Frequency divider 103 ... Control circuit 104 ... Drive pulse selection circuit 105 ... Stepping motor 106 ... Analog display 107 ... Hour hand 108 ... Minute hand 109 ... Second hand 110 ... Rotation detection circuit 111 ... Detection section discrimination circuit 201 ... Stator 202 ... Rotor 203 ... Rotor housing through holes 204, 205 ... Notches (inside notch)
206, 207 ... Notch (outer notch)
208 ... Magnetic core 209 ... Coils 210 and 211 ... Saturable part OUT1 ... First terminal OUT2 ... Second terminals Q1 to Q6 ... Transistors 301 and 302 ... Detection resistor 303 ... Switch control circuit 304 ... Comparator

Claims (5)

In the rotation detection period in which the rotation of the stepping motor is detected, a detection signal generated by the rotation of the stepping motor is detected at a predetermined period, and the stepping motor determines whether or not the detection signal exceeds a predetermined reference threshold value. Rotation detection means for detecting whether or not the rotation, and a control means for driving and controlling the stepping motor with or without changing the main drive pulse according to the detection result by the rotation detection means,
The stepping motor control circuit characterized in that the rotation detecting means detects rotation at a predetermined period in the rotation detection period at a cycle shorter than other periods. Dividing the rotation detection period into a plurality of detection sections;
The stepping motor control circuit according to claim 1, wherein the rotation detection unit detects rotation of a predetermined detection section in the plurality of detection sections at a cycle shorter than other detection sections.   3. The stepping motor control according to claim 2, wherein the control means changes or does not change the main drive pulse in accordance with a detection section in which the rotation detection means detects a detection signal exceeding the reference threshold value. circuit. Between the first and second switch elements connected in series, the third and fourth switch elements connected in series, and the connection point of the first and second switch elements and the connection point of the third and fourth switch elements A stepping motor coil connected to the first switch element; a first series circuit comprising a fifth switch element and a first detection element connected in parallel to the first switch element; and a sixth circuit connected in parallel to the third switch element. A second series circuit composed of a switch element and a second detection element, and the first to fourth switches are controlled in response to a drive pulse during the rotation drive period to cause the current to flow through the coil to rotate the stepping motor. A switch control means for driving and generating a detection signal by controlling the first, third, fifth and sixth switch elements in the rotation detection period; And a discrimination means for the stepping motor the detection signal occurring between the detecting element and the coil based on whether exceeds the reference threshold is determined whether or not the rotation,
The first switch element to the fourth switch element and the switch control means constitute the control means, and the third switch element to the sixth switch element, the first detection element, the second detection element, the discrimination means, and the switch 4. The stepping motor control circuit according to claim 1, wherein the rotation detecting means is constituted by a control means. In an analog electronic timepiece having a stepping motor that rotationally drives a time hand and a stepping motor control circuit that controls the stepping motor,
An analog electronic timepiece using the stepping motor control circuit according to any one of claims 1 to 4 as the stepping motor control circuit.

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