JP2015023644A - Stepping motor control circuit, movement and analog electronic clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve stable driving by securely detecting rotation even in low consumption driving.SOLUTION: A stepping motor control circuit comprises a control section that drives a stepping motor 107 by means of a main drive pulse P1 of energy corresponding to a rotating state detected by a rotation detecting circuit 113, among comb-like main driving pulses P1 of a plurality of types composed by alternately repeating a supply period in which a driving current is supplied to the driving coil of a stepping motor 107 and a supply stop period in which driving current is not supplied. The supply stop period is composed of a first closed section forming a first closed circuit including a driving coil and a detection resistor, and a second closed section forming a second closed circuit composed of an element smaller in impedance than the detection resistor and also composed of the driving coil. When a determination is made based on the rotating state detected by the rotation detecting circuit 113 that the drive margin of the stepping motor 107 does not exceeds a predetermined amount, the control section changes the proportion of the first closed interval, thereby changing the braking force of the stepping motor 107.

Description

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

  Conventionally, in a stepping motor control circuit of an analog electronic timepiece, an induced signal VRs generated by free vibration of the stepping motor is detected in a detection section T after the stepping motor is driven by the main drive pulse P1, and the detected induced signal VRs is detected. A rotation detection circuit that detects a rotation state based on the rotation status is provided (see Patent Documents 1 to 3).

  Further, as a detection method of the rotation detection circuit, the detection section T is divided into a plurality of sections, and it is detected whether or not the induced signal VRs exceeds a predetermined reference threshold voltage Vcomp in each section. Based on the pattern indicating whether or not the induced signal VRs exceeding the threshold voltage Vcomp is detected, it detects whether or not the stepping motor has rotated or the rotation status indicating the margin of the main drive pulse P1 with respect to the load. An invention has been developed in which a driving pulse is selected and driven (see Patent Document 4).

  The analog electronic timepiece equipped with the conventional stepping motor control circuit is configured to supply a driving current from a power source to a driving coil of the stepping motor as a driving pulse when the power consumption is reduced. A method using a comb-like drive pulse constituted by a plurality of comb-like pulses (chopping pulses) generated by alternately repeating a period during which no power is supplied to the drive coil (supply stop period) is employed. (See Patent Document 5).

Driving with a comb-like drive pulse can reduce the current peak, but the drive coil is short-circuited during the supply stop period, so the electromagnetic braking force works and the rotor rotates. The speed is reduced. For this reason, the rotor speed periodically decreases repeatedly, resulting in an apparent load, which hinders low power consumption. In addition, as a result of a decrease in the rotational speed of the rotor, the level of the induced signal VRs decreases, and there is a problem that accurate rotation detection cannot be performed when the load becomes relatively large.
On the other hand, when there is no braking force at all, the rotor behavior becomes unstable due to disturbance (DC magnetic field environment, drop, vibration due to impact, etc.), and therefore an appropriate braking force is required.

Japanese Patent Publication No.57-018440 Japanese Patent Publication No. 63-018148 Japanese Patent Publication No. 63-018149 JP 2009-288133 A JP 05-22996 A

  The present invention has been made in view of the above problems, and an object of the present invention is to enable reliable rotation detection and stable driving even in low-consumption driving.

  According to the first aspect of the present invention, the rotation detection unit that detects the rotation state of the stepping motor in the detection section provided after the stepping motor is driven by the main driving pulse, and the drive current having different energy from each other. Of the plurality of types of comb-shaped main drive pulses configured by alternately repeating a supply period for supplying to the drive coil of the stepping motor and a supply stop period for not supplying the drive current to the drive coil, the rotation A control unit that drives the stepping motor by a main drive pulse having energy corresponding to the rotation state of the stepping motor detected by the detection unit, and the supply stop period includes a drive coil and an element having a predetermined impedance. A first closed section forming one closed circuit, and an impedance smaller than the predetermined impedance And a second closed section that forms a second closed circuit composed of a child coil and the drive coil, and the control unit has a drive margin of the stepping motor that exceeds a predetermined amount based on a rotation state detected by the rotation detection unit. When it is determined that there is no stepping motor control circuit, the braking force of the stepping motor is changed by changing the ratio of the first closed section in the supply stop period.

  According to a second aspect of the present invention, there is provided a movement comprising the stepping motor control circuit.

  According to a third aspect of the present invention, there is provided an analog electronic timepiece comprising the movement.

According to the stepping motor control circuit of the present invention, reliable rotation detection can be performed even with low consumption driving, and stable driving is possible.
Further, according to the movement according to the present invention, it is possible to construct an analog electronic timepiece capable of performing reliable rotation detection even with low consumption driving and capable of stable driving.
In addition, according to the analog electronic timepiece according to the present invention, accurate rotation detection can be performed even in low-power consumption driving, and stable driving is possible.

It is a block diagram of a stepping motor control circuit, a movement, and an analog electronic timepiece according to an embodiment of the present invention. It is a block diagram of the stepping motor used by embodiment of this invention. It is a timing diagram of an embodiment of the invention. It is a determination chart of an embodiment of the invention. It is a partial detailed circuit diagram of an embodiment of the invention. It is a timing diagram of an embodiment of the invention. It is a flowchart of an embodiment of the invention.

FIG. 1 is a block diagram of a stepping motor control circuit, a movement, and an analog electronic timepiece 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 analog electronic timepiece. Is provided with a control circuit 103 that performs control such as control of each electronic circuit element constituting the control, drive pulse change control (pulse control), or braking force control.

  Further, the analog electronic timepiece selects a main drive pulse P1 corresponding to the main drive pulse control signal from the control circuit 103 from a plurality of types of main drive pulses P1 having mutually different energies, and outputs the selected main drive pulse P1. A correction drive pulse generation circuit 105 that outputs a correction drive pulse P2 in response to a correction drive pulse control signal from the control circuit 103 is provided.

  The main drive pulses P1 generated by the main drive pulse generation circuit 104 are drive pulses having different energy levels, and are divided into a plurality of classes (ranks) according to the energy levels. Each main drive pulse P1 includes a period (supply period) in which a drive current from a power source (not shown) is supplied to the drive coil of the stepping motor 107 and a period in which the drive current is not supplied to the drive coil (supply stop period). Are comb-like drive pulses configured by a plurality of comb-like pulses (chopping pulses) formed by alternately repeating.

  The supply stop period includes a first closed section that forms a first closed circuit including a drive coil and an element having a predetermined impedance, and a second closed circuit that includes an element having an impedance smaller than the predetermined impedance and the drive coil. It consists of a closed section. By changing the ratio (rank) of the first closed section in the supply stop period, the magnitude of the braking force (braking force rank) during the period in which the stepping motor 107 is driven by the main drive pulse P1 can be changed. ing.

By using a detection resistor which is a detection element for detecting rotation as an element having a predetermined impedance, a dedicated circuit element is not required, and a transistor is used as an element having an impedance lower than the predetermined impedance. An element having an impedance lower than the predetermined impedance is configured by the on-resistance of the transistor.
The ratio of the first closed section is divided into a plurality of classes (ranks), and the magnitude of the braking force is also divided into a plurality of classes (ranks) so as to correspond to the ranks of the first closed sections. As the rank of the first closed section increases, the ratio of the first closed section increases, and the magnitude of the braking force decreases correspondingly (the rank decreases).

In response to the main drive pulse control signal from the control circuit 103, the main drive pulse generation circuit 104 changes to a main drive pulse P1 with higher energy (rank up) or changes to a main drive pulse P1 with lower energy (rank down). Etc.) to generate the main drive pulse P1 corresponding to the main drive pulse control signal.
In addition, the main drive pulse generation circuit 104 changes the ratio of the first closed section in the supply stop period in response to the main drive pulse control signal from the control circuit 103, thereby controlling the stepping motor 107 in the supply stop period. Control the magnitude of power.

The correction drive pulse generation circuit 105 outputs the correction drive pulse P2 in response to the correction drive pulse control signal from the control circuit 103. The correction drive pulse P2 is a drive pulse having energy larger than each main drive pulse P1, and is a comb-like drive pulse like the main drive pulse P1.
The analog electronic timepiece includes a motor drive circuit 106 that drives the stepping motor 107 by the main drive pulse P1 from the main drive pulse generation circuit 104 and the correction drive pulse P2 from the correction drive pulse generation circuit 105, a stepping motor 107, and a watch case. 108 is provided.

  The analog electronic timepiece is disposed on the outer surface side of the timepiece case 108, and is driven by the stepping motor 107 to rotate. An analog display portion 109 having a time hand 111 for displaying the time and a calendar display portion 112 for displaying the date, a timepiece case A movement 110 is provided in the interior of 108.

The analog electronic timepiece detects an induced signal VRs generated by free vibration of the rotor of the stepping motor 107 and exceeding a predetermined reference threshold voltage (reference threshold value) Vcomp in a predetermined detection section T, and also has a reference threshold. A rotation detection circuit 113 that detects to which section in the detection section T the induced signal VRs exceeding the voltage Vcomp belongs is provided.
As will be described later, in the embodiment of the present invention, the detection section T for detecting whether or not the stepping motor 107 has rotated is divided into three sections T1 to T3. The induced signal VRs is a signal representing the rotation state of the stepping motor 107.

  The rotation detection circuit 113 indicates that the generation timing of the induced signal VRs is delayed as the load of the stepping motor 107 increases or the power supply voltage decreases, so that the energy of the main drive pulse P1 with respect to the load decreases relatively. It is a circuit that detects the rotation state of the stepping motor 107 by using it, and has a configuration that detects the induced signal VRs in the same manner as the rotation detection circuits described in Patent Documents 1 to 4.

  The rotation detection circuit 113 includes a closed circuit including a drive coil of the stepping motor 107 and a detection element for detecting rotation that detects the induced signal VRs generated by the stepping motor 107, the drive coil, and a low impedance element (specifically, The detection cycle is formed by a closed circuit constituted by a transistor, and the rotation state of the stepping motor 107 is detected in a detection section T constituted by a plurality of detection cycles.

  The reference threshold voltage Vcomp is a reference value for determining the voltage level of the induced signal VRs generated by the stepping motor 107. The reference threshold voltage is used when the rotor rotates fast, such as when the stepping motor 107 rotates. When an induced signal VRs exceeding Vcomp is generated and the rotor rotation is slow, such as when the stepping motor 107 does not rotate, the reference threshold voltage is set so that the induced signal VRs does not exceed the reference threshold voltage Vcomp. Vcomp is set.

The oscillation circuit 101, the frequency dividing circuit 102, the control circuit 103, the main drive pulse generation circuit 104, the correction drive pulse generation circuit 105, the motor drive circuit 106, the stepping motor 107, and the rotation detection circuit 113 are components of the movement 110.
In general, a timepiece mechanical body composed of devices such as a timepiece power source and a time reference is called a movement. Electronic devices are sometimes called modules. When the watch is completed, a dial and hands are attached to the movement and housed in a watch case.

  Here, the oscillation circuit 101 and the frequency dividing circuit 102 constitute a signal generation unit, and the analog display unit 109 constitutes a display unit. The rotation detection circuit 113 constitutes a rotation detection unit. The oscillation circuit 101, the frequency dividing circuit 102, the control circuit 103, the main drive pulse generation circuit 104, the correction drive pulse generation circuit 105, and the motor drive circuit 106 constitute a control unit. Further, the oscillation circuit 101, the frequency dividing circuit 102, the control circuit 103, the main drive pulse generation circuit 104, the correction drive pulse generation circuit 105, the motor drive circuit 106, and the rotation detection circuit 113 constitute a stepping motor control circuit 114.

FIG. 2 is a configuration diagram of the stepping motor 107 used in the embodiment of the present invention, and shows an example of a timepiece stepping motor generally used in an analog electronic timepiece.
In FIG. 2, a stepping motor 107 includes a stator 201 having a rotor accommodating through hole 203, a rotor 202 rotatably disposed in the rotor accommodating through hole 203, a magnetic core 208 joined to the stator 201, and a winding around the magnetic core 208. A rotated drive coil 209 is provided. When the stepping motor 107 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 drive 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 the embodiment of the present invention) notch portions (outer notches) 206 are provided on the outer end portion of the stator 201 made of a magnetic material at positions facing each other with the rotor accommodating through hole 203 interposed therebetween. 207 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 so as not to be magnetically saturated by the magnetic flux of the rotor 202 but to be magnetically saturated when the drive 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 in which the drive coil 209 is not excited, the rotor 202 is positioned corresponding to the positioning portion as shown in FIG. 2, in other words, the magnetic pole axis A of the rotor 202 is a line connecting the notches 204 and 205. It is stably stopped at a position orthogonal to the minute (position where the angle between the magnetic pole axis A and the X axis is θ0).

Now, the main drive pulse generator circuit 104 supplies the main drive pulse P1 between the terminals OUT1 and OUT2 of the drive coil 209 (for example, the first terminal OUT1 side is positive and the second terminal OUT2 side is negative). When a current i flows in the direction of the arrow, a magnetic flux is generated in the stator 201 in the direction of the 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 ° in the counterclockwise direction in FIG. 2 by the interaction between the magnetic pole generated in the stator 201 and the magnetic pole of the rotor 202. The magnetic pole axis A is stably stopped at the position of the angle θ1.
Incidentally, the rotation direction (counterclockwise direction in FIG. 2) for causing the normal operation (the hand movement operation because it is an analog electronic timepiece in this embodiment) by rotating the stepping motor 107 is the positive direction. The reverse (clockwise direction) is the reverse direction.

In the next cycle, the main drive pulse generation circuit 104 supplies the main drive pulse P1 having the opposite polarity to the terminals OUT1 and OUT2 of the drive coil 209 (on the first terminal OUT1 side so as to have the opposite polarity to the drive). 2 and the second terminal OUT2 side is the positive electrode), and when a current is passed in the direction indicated by the arrow in FIG. 2, a magnetic flux is generated in the stator 201 in the direction indicated by the arrow. Thereby, the saturable portions 210 and 211 are first saturated, and then the rotor 202 rotates 180 degrees in the same direction (positive direction) as described above due to the interaction between the magnetic pole generated in the stator 201 and the magnetic pole of the rotor 202. The magnetic pole axis A stably stops at the angle θ0 position.
Thereafter, by supplying signals with different polarities (alternating signals) to the drive coil 209 in this way, the above operation is repeated alternately every cycle, and the rotor 202 is rotated counterclockwise by 180 degrees. It is comprised so that it can rotate continuously.

FIG. 3 is a timing chart when the stepping motor 107 is driven by the main drive pulse P1 in the embodiment of the present invention. The energy state of the main drive pulse P1 with respect to the load, the rotational behavior of the rotor 202, and the output timing of the induced signal VRs. The pattern of the induced signal VRs representing the rotation state (a set of determination values of the induced signal VRs in the sections T1 to T3) is also shown.
In FIG. 3, P1 represents the main drive pulse P1 and the region where the rotor 202 is rotationally driven by the main drive pulse P1, and a to e represent the magnetic pole axis A by free vibration after the main drive pulse P1 is stopped. This is an area representing a rotational position.

  A predetermined time after driving by the main drive pulse P1 is a first interval T1, a predetermined time after the first interval T1 is a second interval T2, and a predetermined time after the second interval is a third interval T3. In this way, the entire detection section T starting after driving with the main drive pulse P1 is divided into a plurality of sections (three sections T1 to T3 in the present embodiment). It should be noted that no mask interval is provided in which the induced signal VRs is not detected.

  In each section T1 to T3, the determination value when the induced signal VRs exceeding the reference threshold voltage Vcomp is detected is “1”, and the determination value when the induced signal VRs exceeding the reference threshold voltage Vcomp cannot be detected is “1”. 0 ”. Further, “−” means that the determination value of the induced signal VRs may be “1” or “0”, and the determination of the induced signal VRs is not performed.

When the XY coordinate space where the magnetic pole axis A of the rotor 202 is located by the rotation of the rotor 202 is divided into the first quadrant I to the fourth quadrant IV, the sections T1 to T3 can be expressed as follows.
The load to be driven is a normal load. Here, the normal load means a load that is driven at a normal time, and in the embodiment of the present invention, the load when driving the time hand 111 is a normal load.

  The energy state is a large drive margin (when the drive margin of the main drive pulse P1 exceeds a predetermined amount, the energy state of the main drive pulse P1 with respect to the load is sufficiently large, and the rank of the main drive pulse P1 is reduced to save power. In the rotation in the required state), the section T1 is a section for determining the first forward rotation state of the rotor 202 in the third quadrant III of the space centered on the rotor 202, and the section T2 is the first of the rotor 202 in the third quadrant III. In the third quadrant III, the section T3 is a section for determining the rotation situation after the first reverse rotation of the rotor 202 in the third quadrant III. In the case of the embodiment of the present invention, when the determination value in the section T2 is “1”, the drive margin is sufficiently large, so the determination in the section T3 is unnecessary and is “−”.

  In the embodiment of the present invention, when the drive margin of the stepping motor 107 exceeds a predetermined amount, the drive margin is large (the pattern of the induced signal VRs is ( 0,1,-))), but other energy states may be specified.

  Further, the energy state is in a driving margin (a state in which a relatively small load is increased with respect to a state where the driving margin is large, and the energy state of the main driving pulse P1 with respect to the load is slightly lower than a state where the driving margin is large. In the rotation in a state in which the main drive pulse P1 is maintained), the section T1 is a section for determining the first forward rotation state of the rotor 202 in the second quadrant II, and the section T2 is the rotor 202 in the second quadrant II. A section for determining the first forward rotation state and the first forward rotation state of the rotor 202 in the third quadrant III, and the section T3 determines the rotation state after the first reverse rotation of the rotor 202 in the third quadrant III. It is a section.

  In addition, the energy state is a state where the drive margin is small (a relatively small load is further increased with respect to the energy state during the drive margin, and the energy state of the main drive pulse P1 with respect to the load is slightly lower than during the drive margin) In the rotation in the state in which the rank of the main drive pulse P1 needs to be increased), the section T1 is a section for determining the first forward rotation state of the rotor 202 in the second quadrant II, and the section T2 is the rotor in the second quadrant II. Section T3 is a section for determining the first forward rotation situation of 202 and the first forward rotation situation of the rotor 202 in the third quadrant III. Section T3 shows the rotation situation after the first reverse rotation of the rotor 202 in the third quadrant III. This is a section to be determined.

  In addition, the energy state is a first non-rotation state (a state in which the load further increases relative to the low energy state with a small drive margin and the non-rotation state occurs, and an induced signal exceeding the reference threshold voltage Vcomp in the section T1. In a state where the rotational speed is such that VRs is generated and driving by the correction driving pulse P2 and the rank of the main driving pulse P1 are required to be upgraded by one rank), the section T1 is the first of the rotor 202 in the second quadrant II. The section for determining the forward rotation situation and the first reverse rotation situation, the section T2 is the section for determining the first reverse rotation situation of the rotor 202 in the second quadrant II and the first quadrant I, and the section T3 is in the first quadrant This is a section for determining the first reverse rotation state of the rotor 202 and the rotation state after the second forward rotation.

  Further, the energy state is a second non-rotation state (a state in which the load is further increased relative to the first non-rotation energy state to cause non-rotation, and the induced signal exceeds the reference threshold voltage Vcomp even in the section T1. In a state that does not have a rotational speed for generating VRs and is driven by the correction drive pulse P2 and needs to be upgraded by one rank of the main drive pulse P1, the section T1 is the first of the rotor 202 in the second quadrant II. A section for determining the forward rotation situation and the first reverse rotation situation, section T2 is a section for determining the first reverse rotation situation of the rotor 202 in the second quadrant II and the first quadrant I, and a section T3 is the first quadrant I. This is a section for determining the first reverse rotation state of the rotor 202 and the rotation state after the second forward rotation.

  For example, an example of pulse control will be schematically described with reference to FIG. 3. When the energy state is large in driving margin, the pattern of the induced signal VRs indicating the rotation state (determination value of the section T1, determination value of the section T2, and the section T3) (0, 1,-) is obtained as the (determination value). In this case, the control circuit 103 determines that the drive energy of the stepping motor 107 exceeds a predetermined amount, determines that the drive energy is excessive (drive margin is large), and lowers the drive energy of the main drive pulse P1 by one rank. Perform pulse control. When the main drive pulse P1 is lowered by one rank, the rank may be lowered immediately when the pattern (0, 1,-) is detected, or the pattern (0, 1,-) is continuously repeated a predetermined number of times. It can be configured to rank down when detected.

  Further, when the drive margin is present, a pattern (1, 1, −) of the induced signal VRs is obtained, and the control circuit 103 is a case where the drive margin of the stepping motor 107 does not exceed a predetermined amount, and the rotation (excessive) is not sufficient. (The energy state in the drive margin, which is a rotational state in which there is no energy but can be rotated), and the pulse control is performed so as to maintain the drive energy of the main drive pulse P1.

FIG. 4 is a determination chart summarizing the operation of the embodiment of the present invention. In FIG. 4, as in the case of FIG. 3, the determination value “1” is obtained when the induced signal VRs exceeding the reference threshold voltage Vcomp is detected, and the induced signal VRs exceeding the reference threshold voltage Vcomp is not detected. The determination value is “0”. Further, “−” means that the determination value of the induced signal VRs may be “1” or “0”, and the determination of the induced signal VRs is not performed.
That is, when the section T2 is the determination value “1”, it is an energy state having a magnitude that does not require the main drive pulse P1 to be ranked up, and pulse control can be performed based on the determination values of the sections T1 and T2. The determination of the section T3 is not performed.

  The control circuit 103 detects the presence or absence of the induced signal VRs exceeding the reference threshold voltage Vcomp by the rotation detection circuit 113, and based on the pattern in which the sections T1 to T3 to which the induced signal VRs exceeding the reference threshold voltage Vcomp belongs are determined. With reference to the determination chart of FIG. 4 stored in the control circuit 103, pulse control such as rank-up or rank-down of the main drive pulse P1 or drive by the correction drive pulse P2, and driving to the drive coil 209 of the stepping motor 107 The stepping motor 107 is rotationally controlled by performing control (braking force rank operation in FIG. 4) to change the ratio of the first closed section in the supply stop period in which no current is supplied.

The operation will be schematically described with reference to FIG. 4. The control circuit 103 determines whether the induced signal VRs pattern (0, 1, −) has a large drive margin in the current cycle (current cycle). The main drive pulse P1 used for driving in the next cycle (next cycle) is lowered by one rank. When the main drive pulse P1 is lowered by one rank, the rank may be lowered immediately when the pattern (0, 1,-) is detected, or the pattern (0, 1,-) is continuously repeated a predetermined number of times. It can be configured to rank down when detected.
The control circuit 103 does not change the rank of the main drive pulse P1 used for driving in the next cycle when the drive signal margin state of the induced signal VRs pattern (1, 1, −) is obtained in this cycle. maintain.

When the drive margin of the induced signal VRs pattern (1, 0, 1) is obtained in this cycle, the rank of the main drive pulse P1 used for driving in the next cycle is increased by one rank.
When the non-rotation state of the induced signal VRs pattern (1, 0, 0) or (0, 0, 0) is obtained in this cycle, the correction drive pulse P2 having the same polarity as the driven main drive pulse P1 is used. After driving and forcibly rotating, the main drive pulse P1 used for driving in the next cycle is increased by one rank.

The control circuit 103 performs the braking force rank operation when the driving margin of the stepping motor 107 exceeds a predetermined value (in this embodiment, the VRs pattern is a state with a large driving margin of (0, 1, −)). First, in the case of another energy state, the braking force rank operation is performed.
The control circuit 103 is in a state in which the drive margin does not exceed a predetermined value but the main drive pulse P1 is not ranked up (in this embodiment, the VRs pattern is in the drive margin of (1, 1, 0) and the main drive pulse In the case of maintaining the P1 rank without changing it, the braking force rank operation is performed so that the braking force during the supply stop period is lowered by one rank.
In this way, when the rank of the main drive pulse P1 is not changed, the rank of the braking force is changed so as to lower the rank, thereby enabling driving with more margin using the main drive pulse P1 having the same energy. .

  The control circuit 103 is in a state where the drive margin does not exceed the predetermined value and the main drive pulse P1 is ranked up (in this embodiment, the VRs pattern is (1, 0, 1), the drive margin is small, and the VRs pattern is (1, 0, 0) and (0, 0, 0 non-rotating state), the main drive pulse P1 is increased by one rank and the braking force is set to the maximum rank (max rank). As described above, when the control unit 103 is driven by the new main drive pulse P1, the first drive is performed by setting the ratio of the first closed section to the minimum rank (in other words, the braking force is the maximum rank). Yes. As a result, when driving without changing the rank of the main drive pulse P1 as described above, it is possible to perform control with sufficient margin even with the main drive pulse P1 of the same energy by lowering the rank of the braking force. become.

FIG. 5 is a partial detailed circuit diagram common to the embodiments of the present invention, and is a partial detailed circuit diagram of the main drive pulse generation circuit 104, the correction drive pulse generation circuit 105, the motor drive circuit 106, and the rotation detection circuit 113.
FIG. 6 is a timing diagram of the embodiment of the present invention. The first stage of FIG. 6 (OUT1 in section P1) shows the waveform of the main drive pulse P1 driven in the current cycle, and the rear stage of FIG. 6 (OUT1 in sections T1 to T3) shows the rotation detection waveform in the current cycle (current cycle). Yes. FIG. 6 shows the operation timing when rotationally driven with one polarity (one cycle), and the operation timing when rotationally driven with the other polarity (the other cycle) is omitted.

5 and 6, the switch control circuit 303 turns on the transistors Q2 and Q3 at the same time in response to the main drive pulse control signal (or correction drive pulse control signal) Vi supplied from the control circuit 103 during the rotational drive. The state is repeated at a predetermined cycle, or the transistors Q1 and Q4 are simultaneously turned on at a predetermined cycle to generate comb-like drive pulses P1 and P2 and driven in the forward or reverse direction with respect to the drive coil 209. A current i is supplied, thereby driving the stepping motor 107 to rotate.
For example, when driving with one polarity shown in FIG. 6, the switch control circuit 303 drives the transistors Q1 and Q4 in an off state in response to the main drive pulse control signal Vi in order to supply the drive current i in the supply period. At the same time, the transistors Q2, Q3, Q5, and Q6 are driven to an ON state.

Further, the switch control circuit 303 performs the braking force rank operation during the supply stop period, so that each transistor Q1 has a ratio of the first closed section corresponding to the main drive pulse control signal Vi supplied from the control circuit 103. Controls ~ Q6.
That is, in response to the main drive pulse control signal Vi, the switch control circuit 303 detects rotation with the drive coil 209 by driving the transistors Q1 to Q4 to the off state and the transistors Q5 and Q6 to the on state in the first closed section. The transistors Q1 to Q6 are controlled so as to constitute a first closed circuit including the detection resistors R1 and R2 for use. Further, in the second closed section, the transistors Q1, Q3, Q5, Q6 are turned on and the transistors Q2, Q4 are driven to the off state, thereby comprising the on-resistance of the drive coil 209 and the transistors Q1, Q3 (the drive coil 209 is changed). The transistors Q1 to Q6 are controlled so as to form a second closed circuit (substantially short-circuited by the transistors Q1 and Q3).

At the time of rotation detection, the switch control circuit 303 controls the transistors Q1 to Q6 to any one of an on state, an off state, and a switching state (a state in which the on state and the off state are alternately repeated at a predetermined detection cycle) to detect the detection resistor. Control is performed so that the induced signal VRs is generated in R1 or R2.
When the induced signal VRs exceeding the predetermined reference threshold voltage Vcomp is generated in the detection resistor R1 or R2, the comparator 304 outputs the detection signal Vs at that time.

Transistors Q2 and Q4 are components of the motor drive circuit 106, and transistors Q5 and Q6 and detection resistors R1 and R2 are components of the rotation detection circuit 113. The transistors Q1 and Q3 are components that are used as both the motor drive circuit 106 and the rotation detection circuit 113.
The detection resistors R1 and R2 are impedance elements having a predetermined impedance, and the transistors Q1 and Q3 are impedance elements having an impedance smaller than the predetermined impedance. The transistors Q1 to Q6 constitute an element having a small on-resistance and substantially zero impedance in the on state, and the drive coil 209 is short-circuited when the transistors Q1 and Q3 are simultaneously on.

  As shown in FIG. 6, when the determination value of the sections T1 and T2 in the previous cycle is “1”, the control circuit 103 drives the induced signal VRs pattern (1, 1, −) with reference to the determination chart of FIG. In this cycle, the main drive pulse P1 is maintained without being changed, and the ratio of the first closed section in the supply period is increased by one rank so that the braking force is decreased by one rank to drive the main drive pulse P1 in this cycle. The drive pulse generation circuit 104 is controlled.

  In a certain cycle, when the stepping motor 107 is rotationally driven with the main drive pulse P1, the switch control circuit 303 responds to the main drive pulse control signal Vi from the control circuit 103, and the transistors Q2, Q3 in the supply period of the drive period P1. Are driven so as to be simultaneously turned on in a predetermined cycle, thereby generating a comb-like main drive pulse P1, and a drive current i in the direction of the arrow is applied to the drive coil 209 of the stepping motor 107 by the main drive pulse P1. Supply. Thereby, when the stepping motor 107 rotates, the rotor 202 rotates 180 degrees in the forward direction.

  During the supply stop period, a first closed section that forms a first closed circuit by the drive coil 209 and an impedance element having a predetermined impedance, and a second closed circuit including an impedance element having an impedance smaller than the predetermined impedance (substantially in the present embodiment). And a second closed section that constitutes a short circuit of the drive coil 209), and by changing the ratio of the first closed section according to the energy state of the main drive pulse P1 with respect to the load, The rotational speed of the stepping motor 107 and the strength of braking are controlled.

  In the detection section T (sections T1, T2, T3) starting from the time when the driving of the main drive pulse P1 is completed, the rotation detection circuit 113 detects the rotation state of the stepping motor 107. Based on the detection result, the control circuit 103 controls the driving of the stepping motor 107 by performing pulse control such as selection of the main drive pulse P1 in the next cycle and braking force rank operation in the supply stop period.

  After the driving current i is supplied in the direction of the arrow in FIG. 5 to drive the stepping motor 107 as described above, when the rotation detection circuit 113 detects rotation in the detection period T, detection is performed using the detection resistor R1. Do. In this rotation detection, the switch control circuit 303 drives the transistors Q2, Q4, and Q6 to the off state, the transistors Q3 and Q5 to the on state, and the transistor Q1 to the switching state at the detection cycle.

  In the next cycle, during the supply period of the drive period P1, the stepping motor 107 is driven by switching driving so that the transistors Q1 and Q4 are simultaneously turned on in a predetermined cycle and supplying the drive current i in the direction of the opposite arrow in FIG. . Thereby, when the stepping motor 107 rotates, the rotor 202 rotates 180 degrees in the forward direction.

Thereafter, when the rotation detection circuit 113 detects rotation in the detection period T, the detection is performed using the detection resistor R2. In this case, the switching control circuit 303 drives the transistors Q2, Q4, and Q5 to the off state, the transistors Q1 and Q6 to the on state, and the transistor Q3 to the switching state at the detection cycle.
By repeating the above operation, driving and rotation detection of the stepping motor 107 are continuously performed.
FIG. 7 is a flowchart according to the embodiment of the present invention.

The operation of the embodiment of the present invention will be described below with reference to FIGS.
In FIG. 1, an oscillation circuit 101 generates a reference clock signal having a predetermined frequency, and a frequency dividing circuit 102 divides the signal generated by the oscillation circuit 101 to generate a clock signal serving as a time reference, and a control circuit 103. Output to.
The control circuit 103 counts the clock signal, performs a time counting operation, and outputs a main drive pulse control signal to the main drive pulse generation circuit 104 at a predetermined cycle.

  In this case, the control circuit 103 first sets the rank n of the main drive pulse P1n to 1 and the count value N (PCD counter value) indicating the number of times of continuous drive by the same main drive pulse P1 to 0, and the braking force during the supply stop period. The braking force rank B representing the rank is set to the maximum (in other words, the second closed circuit is formed in the entire supply stop period and the entire supply stop period is set as the second closed section) (see FIG. 7). In step S801, a main drive pulse control signal is output so as to rotationally drive the stepping motor 107 with the main drive pulse P11 having the minimum pulse width (steps S802 and S803).

  In response to the main drive pulse control signal from the control circuit 103, the main drive pulse generation circuit 104 outputs a main drive pulse P11 corresponding to the main drive pulse control signal to the motor drive circuit 106. The motor drive circuit 106 rotationally drives the stepping motor 107 with the main drive pulse P11 having the largest braking force rank B. The stepping motor 107 is rotationally driven by the main drive pulse P11 to rotationally drive the time hand 111 and the calendar display unit 112. As a result, when the stepping motor 107 rotates normally, the analog display unit 109 displays the current time at any time by the time hand 111 and the current date by the calendar display unit 112.

  The control circuit 103 determines whether or not the rotation detection circuit 113 has detected the induced signal VRs of the stepping motor 107 exceeding the predetermined reference threshold voltage Vcomp, and the rotation detection circuit 113 detects the induced signal VRs at the detection time t. Determines whether or not it is determined that it is within the section T1 (that is, whether or not the rotation detection circuit 113 has detected the induced signal VRs exceeding the reference threshold voltage Vcomp within the section T1) (step S804).

  When the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is not detected in the section T1 in the processing step S804 (the pattern is (0, x, x)). In this case, the determination value “x” means that the determination value is “1” or “0”.) Whether or not the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the section T2. Determination is made (step S805).

  The control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the section T2 in the processing step S805 (the case where the pattern is (0, 1, x), and the driving margin of FIG. 1 is added to the count value N (step S806), and it is determined whether or not the count value N after the addition has reached a predetermined value (the number of continuous driving times is a predetermined number (for example, 80 times)). (Step S807).

  When the control circuit 103 determines that the count value N has reached a predetermined value in process step S807, when it is determined that the rank n of the main drive pulse P1 is not the minimum rank (rank with the minimum energy) min (step S808). In the next cycle, control is performed so that the rank n of the main drive pulse P1 is lowered by 1 (step S809), the count value N is reset to 0 (step S810), and then the process returns to the processing step S803 to drive the next cycle. .

When determining that the rank n of the main drive pulse P1 is the minimum rank min in the process step S808, the control circuit 103 proceeds to the process step S810.
If the control circuit 103 determines in step S807 that the count value N has not reached the predetermined value, the control circuit 103 immediately returns to process step S803 to drive the next cycle.
If the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp has not been detected in the section T2 in the processing step S805 (the case where the pattern is (0, 0, x)), the reference. It is determined whether or not the induced signal VRs exceeding the threshold voltage Vcomp is detected within the section T3 (step S816).

  If the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is not detected in the section T3 in the processing step S816 (the pattern is (x, 0, 0), the non-shown in FIG. 4). In this case, the correction drive pulse control signal is output to the correction drive pulse generation circuit 105 so that the stepping motor 107 is driven by the correction drive pulse P2 having the same polarity as the main drive pulse P1 in the processing step S803. (Step S811). The correction drive pulse generation circuit 105 forcibly rotates the stepping motor 107 via the motor drive circuit 106 in response to the correction drive pulse control signal.

  Next, the control circuit 103 determines whether or not the rank n of the main drive pulse P1 is the maximum rank max (step S812). If the rank is not the maximum rank, the rank of the main drive pulse P1 is increased by 1 (step S813). Then, the braking power rank B is set to the maximum rank max (step S814), the count value N is reset to 0 (step S815), and the process returns to the processing step S803. As a result, in the next cycle, the driving force rank is the maximum rank max, and the main drive pulse P1 with the energy rank increased by one is driven.

If the rank n of the main drive pulse P1 is determined to be the maximum rank max in process step S812, the control circuit 103 proceeds to process step S815 because the rank cannot be increased.
If the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the section T3 in the processing step S816 (the pattern is (x, 0, 1), the drive margin of FIG. 4 is small). In this case, the process proceeds to processing step S812.

  When the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the section T1 in the processing step S804 (the case where the pattern is (1, x, x)), the reference. It is determined whether or not the induced signal VRs exceeding the threshold voltage Vcomp is detected within the section T2 (step S817).

The control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is not detected in the section T2 in the processing step S817 (the case where the pattern is (1, 0, x) and the drive margin is small). Or it is a case of non-rotation.), It transfers to processing step S816.
The control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the section T2 in the processing step S817 (when the pattern is (1, 1, x) and the drive margin is within the range). The count value N is reset to 0 (step S818).

  Next, the control circuit 103 determines whether or not the braking force rank B is the minimum rank min (step S819). If the braking force rank B is not the minimum rank min, the braking force rank B is lowered by 1 (in other words, Then, after the first closed section is increased by one rank (step S820), the process returns to step S803. When determining that the braking force rank B is the minimum rank min in the processing step S819, the control circuit 103 immediately returns to the processing step S803.

  As described above, the stepping motor control circuit 114 according to the embodiment of the present invention includes the rotation detection circuit 113 that detects the rotation state of the stepping motor 107 in the detection section T provided after the stepping motor 107 is driven by the main drive pulse P1. A plurality of types configured by alternately repeating a supply period in which drive current i is supplied to the drive coil 209 of the stepping motor 107 and a supply stop period in which the drive current i is not supplied to the drive coil 209 have different energies. A control unit that drives the stepping motor 107 by the main driving pulse P1 having energy corresponding to the rotation state of the stepping motor 107 detected by the rotation detection circuit 113 among the comb-shaped main driving pulses P1 During the stop period, the drive coil 209 and the predetermined impedance are detected. A first closed section that forms a first closed circuit including the resistor T1 or R2, and a second closed section that forms a second closed circuit including an element having an impedance smaller than the predetermined impedance and the drive coil 209, and When the control unit determines that the drive margin of the stepping motor 107 does not exceed a predetermined amount based on the rotation state detected by the rotation detection circuit 113, the control unit changes the ratio of the first closed section in the supply stop period. It is characterized in that the braking force of the stepping motor 107 is changed.

Here, when the control unit determines that the drive margin of the stepping motor 107 does not exceed a predetermined amount based on the rotation state detected by the rotation detection circuit 113 and maintains the main drive pulse P1, the supply stop The ratio of the first closed section in the period can be increased by one rank.
In addition, the controller may be configured to drive the first drive with the ratio of the first closed section as the minimum rank when driven by each main drive pulse P1.

  Further, the detection interval T is divided into a first interval T1 after driving by the main drive pulse P1, a second interval T2 after the first interval T1, and a third interval T3 after the second interval T2, and the load When the energy state of the main drive pulse P1 with respect to the state in which the main drive pulse P1 is maintained, the first interval T1 is the first positive of the rotor 202 in the second quadrant II of the space centered on the rotor 202 of the stepping motor 107. A section for determining the direction rotation state, a section for determining the first positive rotation state of the rotor 202 in the second quadrant II and the first positive rotation state of the rotor 202 in the third quadrant III between the second section T2 and the second section T2. The third section T3 is a section for determining the rotation state after the first reverse rotation of the rotor 202 in the third quadrant III, and the controller detects that the rotation detection circuit 113 is in the third section T3. The ratio between the first closed section together with the time of detecting the induced signal VRs exceeding the reference threshold Vcomp to have ranks up the main drive pulse P1 can be configured to drive with a minimum rank.

Further, the detection interval T is divided into a first interval T1 after driving by the main drive pulse P1, a second interval T2 after the first interval T1, and a third interval T3 after the second interval T2, and the load When the energy state of the main drive pulse P1 with respect to the state in which the main drive pulse P1 is maintained, the first interval T1 is the first positive of the rotor 202 in the second quadrant II of the space centered on the rotor 202 of the stepping motor 107. The second section T2 is a section for determining the first rotational state of the rotor 202 in the second quadrant II, and the third section T2 is a section for determining the first forward rotational state of the rotor 202 in the third quadrant III. The section T3 is a section for determining a rotation state after the first reverse rotation of the rotor 202 in the third quadrant III, and the controller detects that the rotation detection circuit 113 is in the first section T1. When detecting the induced signal VRs exceeding the reference threshold Vcomp to have can be configured to determine the driving margin of the stepping motor 107 does not exceed a predetermined amount.
The element having the predetermined impedance may be configured to be a detection resistor R1 or R2 for detecting rotation.

Therefore, reliable rotation detection can be performed even with low-consumption driving, and stable driving can be performed.
Further, since the braking force can be controlled based on the rotation detection result by controlling the ratio of the first closed section in the supply stop section, the induced signal VRs decreases due to the relative increase in the load, and the detection is impossible. Can be prevented, and the influence of disturbance can be reduced. Therefore, an appropriate braking force can be obtained, which contributes to a reduction in current and an improvement in the accuracy of rotation detection.

Further, when the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the sections T1 and T2, the rank of the main drive pulse P1 is maintained without being changed, but the braking force is increased by raising the first closed section by one rank. Is reduced by one rank, thereby increasing the rotational angular velocity of the rotor. As a result, the period during which the main drive pulse P1 of the same rank can be driven increases, and the battery life is extended.
Further, when the rank of the main drive pulse P1 is increased and the driving force is increased, the braking force is returned to the maximum rank, so that a strong state against disturbance can be obtained and stable driving can be obtained.

Further, according to the movement according to the present invention, it is possible to construct an analog electronic timepiece capable of performing reliable rotation detection even with low consumption driving and capable of stable driving.
In addition, according to the analog electronic timepiece according to the present invention, accurate rotation detection can be performed even in low-power consumption driving, and stable driving is possible.

  In each of the above embodiments, the detection section T is configured by three sections. However, the detection section T is divided into two or more sections, and the rotation state of the stepping motor is determined by the pattern of the determination value of the induced signal VRs in these sections. You may make it comprise so that it may detect.

The stepping motor control circuit according to the present invention is applicable to various electronic devices that use the stepping motor.
The movement according to the present invention is applicable to movements used in various analog electronic timepieces such as analog electronic wristwatches and analog electronic table clocks.
The analog electronic timepiece according to the present invention is applicable to various analog electronic timepieces such as an analog electronic wristwatch and an analog electronic table clock.

DESCRIPTION OF SYMBOLS 101 ... Oscillation circuit 102 ... Frequency division circuit 103 ... Control circuit 104 ... Main drive pulse generation circuit 105 ... Correction drive pulse generation circuit 106 ... Motor drive circuit 107 ... Stepping motor 108 ... Clock case 109 ... Analog display unit 110 ... Movement 111 ... Time hand 112 ... Calendar display unit 113 ... Rotation detection circuit 114 ... Stepping motor control circuit 201 ... Stator 202... Rotor 203... Rotor accommodating through-holes 204 and 205... Notch (inner notch)
206, 207 ... Notch (outer notch)
208 ... Magnetic core 209 ... Drive coils 210, 211 ... Saturable part 303 ... Switch control circuit 304 ... Comparator OUT1 ... First terminal OUT2 ... Second terminals Q1-Q8 ..Transistors R1, R2 ... Detection resistors

Claims (8)

A rotation detection unit for detecting a rotation state of the stepping motor in a detection section provided after the stepping motor is driven by the main drive pulse;
Plural types of comb teeth having different energies and configured by alternately repeating a supply period for supplying a drive current to the drive coil of the stepping motor and a supply stop period for not supplying the drive current to the drive coil A control unit that drives the stepping motor with a main driving pulse having energy corresponding to a rotation state of the stepping motor detected by the rotation detection unit among the main driving pulses in a shape,
The supply stop period forms a first closed section that forms a first closed circuit including an element having a predetermined impedance with the drive coil, and a second closed circuit including an element having an impedance smaller than the predetermined impedance and the drive coil. And a second closed section
When the control unit determines that the driving margin of the stepping motor does not exceed a predetermined amount based on the rotation state detected by the rotation detection unit, the control unit changes the ratio of the first closed section in the supply stop period. A stepping motor control circuit characterized in that the braking force of the stepping motor is changed by the step.   When the control unit determines that the drive margin of the stepping motor does not exceed a predetermined amount based on the rotation state detected by the rotation detection unit and maintains the main drive pulse, the control unit in the supply stop period 2. The stepping motor control circuit according to claim 1, wherein the ratio of one closed section is increased by one rank.   3. The stepping motor control circuit according to claim 1, wherein when the control unit is driven by a main drive pulse, the first drive is performed with the ratio of the first closed section being minimized. The detection section is divided into a first section after driving with a main drive pulse, a second section after the first section, and a third section after the second section,
When the energy state of the main drive pulse with respect to the load is a state in which the main drive pulse is maintained, the first section is the first forward rotation state of the rotor in the second quadrant of the space around the rotor of the stepping motor. The second section is a section for determining the first positive rotation situation of the rotor in the second quadrant and the first positive rotation situation of the rotor in the third quadrant, and the third section is the section A section for determining a rotation state after the first reverse rotation of the rotor in the third quadrant;
When the rotation detection unit detects an induced signal exceeding the reference threshold value in the third section, the control section ranks up the main drive pulse and drives the ratio of the first closed section to the minimum rank. The stepping motor control circuit according to claim 3, wherein The detection section is divided into a first section after driving with a main drive pulse, a second section after the first section, and a third section after the second section,
When the energy state of the main drive pulse with respect to the load is a state in which the main drive pulse is maintained, the first section is the first forward rotation state of the rotor in the second quadrant of the space around the rotor of the stepping motor. The second section is a section for determining the first positive rotation situation of the rotor in the second quadrant and the first positive rotation situation of the rotor in the third quadrant, and the third section is the section A section for determining a rotation state after the first reverse rotation of the rotor in the third quadrant;
The control unit determines that a drive margin of the stepping motor does not exceed a predetermined amount when the rotation detection unit detects an induced signal exceeding the reference threshold in the first section. Item 5. A stepping motor control circuit according to any one of Items 1 to 4.   6. The stepping motor control circuit according to claim 1, wherein the element having the predetermined impedance is a detection resistor for detecting rotation.   A movement comprising the stepping motor control circuit according to any one of claims 1 to 6.   An analog electronic timepiece comprising the movement according to claim 7.

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