JP2012217327A - Stepping motor control circuit and analog electronic clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent waste of energy by accurately detecting a load state of a stepping motor.SOLUTION: The stepping motor control circuit comprises: a rotation detection circuit 111 which compares an induction signal VRs generated by a rotation of a stepping motor 105 with a standard threshold voltage Vcomp to detect a rotation state of the stepping motor 105; control means which controls the rotation of the stepping motor 105 by selecting a drive pulse according to the rotation state of the stepping motor 105 from a various types of drive pulses containing a main drive pulse P1 which drives at a normal time, a drive pulse Pf for loads with a larger energy than that of the main drive pulse P1, and a correction drive pulse P2 with a larger energy than that of the drive pulse Pf for loads; and an electric current detection circuit 112 which detects excitation current which flows into the stepping motor 105 by the rotation control. When the electric current detection circuit 112 detects a peak value of the excitation current which exceeds a predetermined value Pcomp, the control means controls the rotation of the stepping motor 105 by selecting the drive pulse Pf for loads.

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 drive coil, two terminals OUT1 and OUT2 of the drive coil are provided. A stepping motor that supplies alternating drive signals having different polarities to each other to rotate the rotor by generating magnetic flux in the stator and stops the rotor at a position corresponding to the positioning portion is an analog electronic device. Used in watches and the like.

Conventionally, in detecting the load state of an analog electronic timepiece, the peak of the excitation current flowing in the drive coil of the stepping motor is detected, and the pulse width (corresponding to drive energy) of the main drive pulse is determined according to the magnitude. There is a system (see, for example, Patent Document 1).
In addition, in the rotation detection of the analog electronic timepiece, a means for comparing and discriminating the detection time of the induced voltage generated by the rotation of the rotor of the stepping motor with the reference time is provided, and the count advances when the detection time is earlier than the reference time. There is a method of reducing the current consumption by narrowing the pulse width of the main drive pulse by one rank (pulse down) (see, for example, Patent Document 2).

  In an analog electronic timepiece, if significant wear of the train wheel occurs partially, sudden load fluctuations occur periodically or continuously, and the rotational speed of the rotor is reduced. The analog electronic timepieces described in Patent Documents 1 and 2 are configured such that when the determination value does not reach a predetermined value, the stepping motor is determined to be non-rotating and is driven to rotate by a correction driving pulse having energy larger than that of the main driving pulse. is doing. Therefore, when the abrupt load fluctuation occurs, the rotational speed of the rotor cannot be higher than the predetermined speed. Therefore, even if the rotor is rotating, the induced signal does not reach the predetermined reference value, and the correction drive pulse is unnecessary. There is a problem of rotational driving.

  In particular, as in Patent Document 2, in the case of an analog electronic timepiece having a system in which a plurality of main drive pulses are prepared and the drive drive energy is insufficient and the system is ranked up to a main drive pulse having a large energy, a sudden load increase occurs. Each time it occurs, the energy rank of the main drive pulse increases. Therefore, when the load generation cycle is short, there is no opportunity to rank down, and the main drive pulse of the highest rank is fixed, and there is a problem that power consumption increases.

JP-A-53-42860 International Publication No. 2005/119377

The present invention has been made in view of the above problems, and an object of the present invention is to provide a stepping motor control circuit capable of accurately detecting a load state of a stepping motor and preventing waste of energy.
Another object of the present invention is to provide an analog electronic timepiece capable of accurately detecting the load condition of a stepping motor and preventing waste of energy.

  According to a first aspect of the present invention, an induced signal generated by rotation of a rotor of a stepping motor is detected, and the rotational state of the stepping motor is detected by comparing the induced signal with a predetermined reference threshold voltage. Among a plurality of types of drive pulses, including a rotation detection means, a main drive pulse that is driven in a normal state, a load drive pulse having a higher energy than the main drive pulse, and a correction drive pulse having a higher energy than the load drive pulse Control means for controlling the rotation of the stepping motor by selecting a driving pulse corresponding to the rotation state of the stepping motor, and current detection means for detecting an excitation current flowing through the stepping motor by the rotation control of the stepping motor. When the current detection means detects a peak value of the excitation current exceeding a predetermined value, the control It means a stepping motor control circuit, characterized by rotation control of the stepping motor by selecting the load driving pulse is provided.

  According to the second aspect of the present invention, an induced signal generated by the rotation of the rotor of the stepping motor is detected, and the rotational state of the stepping motor is detected by comparing the induced signal with a predetermined reference threshold voltage. Rotation detection means, control means for selecting a drive pulse corresponding to the rotation state of the stepping motor from among a plurality of drive pulses and controlling the rotation of the stepping motor, and flow to the stepping motor by rotation control of the stepping motor Current detection means for detecting an excitation current, a plurality of types of voltages are prepared as the reference threshold voltage, the rotation detection means, depending on the magnitude of the excitation current detected by the current detection means, A stepping motor control circuit is provided that changes the reference threshold voltage.

  According to a third aspect of the present invention, in the analog electronic timepiece having a stepping motor that rotationally drives a time hand and a stepping motor control circuit that controls the stepping motor, the stepping motor control circuit includes the above description. An analog electronic timepiece using the stepping motor control circuit is provided.

According to the stepping motor control circuit of the present invention, it is possible to accurately detect the load state of the stepping motor and prevent waste of energy.
In addition, according to the analog electronic timepiece according to the invention, it is possible to accurately detect the load state of the stepping motor and prevent waste of energy.

It is a block diagram of the analog electronic timepiece concerning the 1st, 3rd-6th embodiment of the present invention. It is a block diagram of the stepping motor used for the analog electronic timepiece which concerns on the 1st, 2nd, 4th, 5th embodiment of this invention. It is a partial detailed circuit diagram of the stepping motor control circuit according to the first to sixth embodiments of the present invention. It is a flowchart of the stepping motor control circuit which concerns on the 1st, 4th, 5th embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 1st Embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 1st, 3rd-6th embodiment of this invention. It is operation | movement explanatory drawing of the stepping motor control circuit which concerns on the 1st-6th embodiment of this invention. It is a block diagram of an analog electronic timepiece according to a second embodiment of the present invention. It is a timing diagram of the stepping motor control circuit which concerns on the 2nd Embodiment of this invention. It is a determination chart of the stepping motor control circuit according to the second embodiment of the present invention. It is a flowchart of the stepping motor control circuit which concerns on the 2nd Embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 2nd Embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 2nd Embodiment of this invention. It is a block diagram of the stepping motor used for the analog electronic timepiece which concerns on the 3rd, 6th embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 3rd, 6th embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 3rd Embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 4th Embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 5th Embodiment of this invention. It is a flowchart of the stepping motor control circuit which concerns on the 6th Embodiment of this invention.

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 addition, in each figure, the same code | symbol is attached | subjected to the same component and the part which performs the same process.
FIG. 1 is a block diagram of an analog electronic timepiece using a stepping motor control circuit common to the first, third to sixth embodiments 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 and change control of a drive pulse, and selects a drive pulse corresponding to a control signal from the control circuit 103 from a plurality of types of drive pulses for motor rotation drive The output driving pulse selection circuit 104, the stepping motor 105 that is rotationally driven by the driving pulse from the driving pulse selection circuit 104, and the time hand that is rotationally driven by the stepping motor 105 to display the time (in the example of FIG. , Minute hand 108 and second hand 110) and an analog display unit 106 having a calendar display unit 109. .

Further, the analog electronic timepiece detects an induced signal VRs that indicates the rotation state of the stepping motor 105, and outputs a rotation detection signal that indicates whether or not the induced signal VRs exceeds a predetermined reference threshold voltage Vcomp. When the stepping motor 105 is rotationally driven by the drive pulse, the excitation current flowing through the drive coil is detected, and a current detection signal indicating whether the peak value of the excitation current exceeds a predetermined reference threshold current Pcomp is output. The current detection circuit 112 is provided.
When the stepping motor 105 rotates, the rotation detection circuit 111 detects the induced signal VRs exceeding the reference threshold voltage Vcomp, and when the stepping motor 105 does not rotate, the rotation detection circuit 111 generates the reference threshold voltage Vcomp. The reference threshold voltage Vcomp is set so as not to detect the induced signal VRs exceeding.

When the stepping motor 105 is rotationally driven by the drive pulse, the current detection circuit 112 detects the excitation current flowing through the drive coil, and determines whether or not the peak value of the excitation current exceeds a predetermined reference threshold current Pcomp ( In other words, a current detection signal representing a load state) indicating whether or not the load exceeds a predetermined value is output. The magnitude of the peak value of the exciting current corresponds to the magnitude of the load driven by the stepping motor 105. When the peak value exceeds the reference threshold current Pcomp, the load exceeds the predetermined value. It represents something.
When it is determined that the current detection circuit 112 has not detected the peak value of the excitation current exceeding the reference threshold current Pcomp based on the current detection signal, the control circuit 103 indicates that the load does not exceed the predetermined value. judge. On the other hand, when the control circuit 103 determines that the current detection circuit 112 has detected the peak of the excitation current exceeding the reference threshold current Pcomp based on the current detection signal, the load has increased beyond a predetermined value. The drive pulse selection circuit 104 is controlled so that the stepping motor 105 is rotationally driven by the load drive pulse Pf whose energy is larger than that of the main drive pulse P1.

The rotation detection circuit 111 uses a preset reference threshold voltage Vcomp to indicate whether the induced signal VRs of the stepping motor 105 exceeds the reference threshold voltage Vcomp (in other words, the rotation state of the stepping motor 105). The rotation detection signal is output to the control circuit 103.
The control circuit 103 determines whether or not the stepping motor 105 has rotated based on the rotation detection signal. If it is determined that the stepping motor 105 has not rotated, the correction drive has a larger energy than the main drive pulse P1 and the load drive pulse Pf. The drive pulse selection circuit 104 is controlled to forcibly rotate the stepping motor 105 by the pulse P2.
Here, the oscillation circuit 101 and the frequency dividing circuit 102 constitute an example of a signal generation unit, and the analog display unit 106 constitutes an example of a display unit. The rotation detection circuit 111 and the control circuit 103 constitute an example of rotation detection means, and the current detection circuit 112 constitutes an example of current detection means. The oscillation circuit 101, the frequency divider circuit 102, the control circuit 103, and the drive pulse selection circuit 104 constitute an example of a control unit.

FIG. 2 is a configuration diagram of the stepping motor 105 of FIG. 1 in the first, second, fourth, and fifth embodiments, and shows an example of a stepping motor for a watch that is generally used in an analog electronic timepiece. ing.
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 drive coil 209 is provided. When the stepping motor 105 is used for an analog electronic timepiece, the stator 201 and the magnetic core 208 are fixed to a base plate (not shown) by screws or caulking (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 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 so as not to be magnetically saturated by the magnetic flux of the rotor 202 but to be magnetically saturated and to increase the magnetic resistance when excited by flowing an exciting current through the coil 209. 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 no excitation current is supplied to the drive coil 209, 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 notched portions 204, 205. Is stably stopped at a stable stationary position (a position that forms an angle θ0 with the direction X of the magnetic flux flowing through the stator 201) orthogonal to the line segment connecting the two.
Now, a rectangular-wave drive pulse of one polarity is supplied from the drive pulse selection circuit 104 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 an exciting current i is passed in the direction of the arrow in FIG. 2, magnetic flux is generated in the stator 201 in the direction of the dashed 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 at the stable stationary position at the angle θ1 position.

  Next, the drive pulse selection circuit 104 supplies a drive pulse with a reverse polarity rectangular wave to the terminals OUT1 and OUT2 of the drive coil 209 (the first terminal OUT1 side is set to a negative polarity so as to have a reverse polarity to the drive). When the exciting current i flows in the direction opposite to the arrow in FIG. 2, a magnetic flux is generated in the stator 201 in the direction indicated by the broken line. 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 the angle θ0 is stabilized. Stops stably at a stationary position.

Thereafter, by supplying currents (alternating signals) having different polarities to the drive coil 209 in this way, the above operation is repeated, and the rotor 202 is continuously rotated 180 degrees in the direction of the solid arrow. It is configured to be able to.
In this embodiment, as will be described later, one type of main drive pulse P1 that can rotate the load and is used for normal driving is used as the drive pulse, and the stepping motor 105 is used when the load is greater than a predetermined value. Correction used when the driving energy is larger than the driving pulse Pf for load and the driving pulse Pf for load having a larger driving energy than the main driving pulse P1 used for reliable rotation, and the stepping motor 105 cannot be rotated due to a large load. A plurality of types of drive pulses including the drive pulse P2 are used.

FIG. 3 is a circuit diagram common to the first to sixth embodiments of the present invention, and is a circuit diagram showing in detail a part of the drive pulse selection circuit 104, the rotation detection circuit 111, and the current detection circuit 112 in FIG. It is.
In FIG. 3, N channel MOS transistors Q 1 and Q 2, P channel MOS transistors Q 3 and Q 4, and switch control circuit 303 are components of drive pulse selection circuit 104. A drive coil 209 of the stepping motor 105 is connected between the source connection point of the transistors Q1 and Q3 and the source connection point of the transistors Q2 and Q4.

P-channel MOS transistors Q3 to Q6, a detection resistor 301 as an example of a detection element connected in series to the transistor Q5, a detection resistor 302 as an example of a detection element connected in series to the transistor Q6, a switch control circuit 303, and a comparator Reference numeral 304 denotes a component of the rotation detection circuit 111. The detection resistors 301 and 302 are detection elements used for rotation detection, and generate an induction signal VRs when rotation is detected.
Transistors Q3 and Q4 are components of the current detection circuit 112. When the stepping motor 105 is rotationally driven, an exciting current is passed through the drive coil 209. The voltage generated in the channel impedance of the transistor Q3 or Q4 by the exciting current becomes a value corresponding to the exciting current. The current detection circuit 112 detects whether or not the peak value of the excitation current exceeds the reference threshold current Pcomp by comparing the voltage generated in the channel impedance with a predetermined reference voltage, and outputs a current detection signal indicating this. Output.

The gates of the transistors Q1 to Q6 are connected to the switch control circuit 103. A connection point OUT2 between the detection resistor 301 and the drive coil 209 and a connection point OUT1 between the detection resistor 302 and the drive coil 209 are connected to an input portion of the comparator 304. The reference threshold voltage Vcomp is input to the input unit of the comparator 304 when the rotation of the stepping motor 105 is detected.
When the stepping motor 105 is rotationally driven, the switch control circuit 303 simultaneously turns on the transistors Q2 and Q3 in response to the rotational drive control pulse Vi corresponding to the drive pulse supplied from the control circuit 103, or By simultaneously turning on the transistors Q1 and Q4, an exciting current is supplied to the drive coil 209 in the forward direction or the reverse direction, thereby driving the stepping motor 105 to rotate.

At this time, as shown in FIG. 7, an excitation current corresponding to the magnitude of the load flows through the drive coil 209. In FIG. 7, when the stepping motor 105 is driven by the main drive pulse P1 (pulse width is from time t0 to time t2), an excitation current having a waveform corresponding to the magnitude of the load flows through the drive coil 209. The excitation current waveform has a peak (maximum value) immediately after the start of driving the main drive pulse P1, and then a valley (minimum value). Waveform 1 shows an excitation current waveform when the load is small, waveform 2 shows a medium load, waveform 3 shows an excitation current waveform when the load is larger than a predetermined value, and an excitation current value (peak value) at a valley (peak K) Fluctuates according to the magnitude of the load.
The current detection circuit 112 detects an excitation current value (peak value) at a peak detection time t1, that is, a peak K when a predetermined time (for example, 3 msec) has elapsed from the start of driving by the driving pulse P1. The peak value is a minimum value of the excitation current that appears after a mountain that occurs immediately after the start of driving with a drive pulse.

  When the load of the stepping motor 105 is less than or equal to a predetermined value, as shown in waveforms 1 and 2, the peak value of the excitation current becomes equal to or less than a predetermined reference current Pcomp at a predetermined time point t1. On the other hand, when the load increases and exceeds a predetermined value, the peak value of the excitation current exceeds the reference current Pcomp as shown by the waveform 3. The current detection circuit 112 outputs a current detection signal indicating whether or not the peak value of the excitation current exceeds Pcomp. Specifically, the current detection circuit 112 compares the voltage generated in the channel impedance of the transistor Q3 or Q4 with a predetermined reference voltage when the exciting current flows through the transistor Q3 or the transistor Q4 in the on state, whereby It is detected whether or not the excitation current exceeds the reference threshold current Pcomp.

The control circuit 103 selects a drive pulse based on the detection result of the current detection circuit 112, and performs rotation detection in the subsequent rotation detection period.
When the rotation detection circuit 111 detects the induced signal VRs generated by the free vibration of the stepping motor 105 after being rotated during the rotation detection period, the switch control circuit 303 responds to the rotation detection control pulse Vi from the control circuit 103. Thus, 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, The induced signal VRs is detected by the comparator 304.

  When the comparator 304 detects the induced signal VRs exceeding the set reference threshold voltage Vcomp among the induced signals VRs induced in the stepping motor 105 (in other words, the drive coil 209), the comparator 304 exceeds the set reference threshold voltage Vcomp. A detection signal Vs indicating that the signal VRs has been detected is output. When the control circuit 103 determines that the stepping motor 105 has rotated based on the detection signal, the control circuit 103 performs drive control of the next cycle without performing the drive by the correction drive pulse P2. If the control circuit 103 determines that the stepping motor 105 has not rotated based on the detection signal Vs, the control circuit 103 performs driving by the correction driving pulse P2 to forcibly rotate the stepping motor 105.

FIG. 4 is a flowchart showing operations of the stepping motor control circuit and the analog electronic timepiece common to the first, fourth and fifth embodiments of the present invention, and is a flowchart mainly showing processing of the control circuit 103.
FIG. 5 is a flowchart showing operations of the stepping motor control circuit and the analog electronic timepiece according to the first embodiment of the present invention, and is a flowchart mainly showing processing of the control circuit 103.
FIG. 6 is a flowchart showing the operations of the stepping motor control circuit and the analog electronic timepiece common to the first, third to sixth embodiments of the present invention, and is a flowchart mainly showing the processing of the control circuit 103.

Hereinafter, the operations of the stepping motor control circuit and the analog electronic timepiece according to the first embodiment of the present invention will be described in detail with reference to FIGS.
First, the operation in the normal mode in which the time measurement operation is performed and the time is displayed will be described.
The oscillating circuit 101 generates a reference clock signal having a predetermined frequency, and the frequency dividing circuit 102 divides the signal generated by the oscillating circuit 101 and outputs a clock signal serving as a time reference to the control circuit 103 at predetermined intervals.
The control circuit 103 sets the drive pulse to the main drive pulse P1, resets the count value PN in the control circuit 103 to 0 (step S401), counts the clock signal, and performs a time counting operation. Here, the count value PN is a count value for counting the number of times the excitation current is detected.

The control circuit 103 outputs a control signal so as to rotationally drive the stepping motor 105 with the main drive pulse P1 having a predetermined energy every time the clock signal is counted (step S402). In response to the control signal from the control circuit 103, the drive pulse selection circuit 104 rotationally drives the stepping motor 105 with the main drive pulse P1. The stepping motor 105 is rotated by the main drive pulse P1 to perform the hand movement driving of the time hand (the hour hand 107, the minute hand 108, the second hand 110) of the analog display unit 106 and the date feed driving of the calendar display unit 109.
In this manner, the main hand driving pulse P1 performs the hand movement operation (normal hand movement) for driving the time hands 107 to 108, 110 to rotate forward at a predetermined hand movement interval (one second interval in the present embodiment). Then, the date display driving of the calendar display unit 109 is performed. As a result, the current time is displayed by the time hands 107, 108, and 110 of the analog display unit 106, and the date of the day is displayed by the calendar display unit 109.

Next, the control circuit 103 determines whether or not a periodic load detection period has arrived (step S403). Here, the periodic load detection period indicates a load detection timing for detecting whether or not the load of the stepping motor 105 has periodically increased. A periodic load means a load that increases or decreases at a constant cycle. For example, a load that periodically fluctuates beyond a predetermined value due to significant wear of the train wheel (periodic load) or a calendar load. Etc.
When the control circuit 103 determines in step S403 that the periodic load detection period has come, the control circuit 103 detects the excitation current of the stepping motor 105 and shifts to a detection mode for changing the drive pulse to the load drive pulse Pf. If it is determined that the periodic load detection period has not arrived, the process returns to step S402.

In the detection mode, as shown in FIG. 5, the control circuit 103 controls the drive pulse selection circuit 104 to drive the stepping motor with the main drive pulse P1 (step S501), and adds 1 to the count value PN (step S502). ).
Next, the control circuit 103 causes the current detection circuit 112 to detect the peak value of the excitation current of the stepping motor 105 (step S503), and then causes the rotation detection circuit 111 to detect the induction signal VRs of the stepping motor 105 (step S504). . The current detection circuit 112 and the rotation detection circuit 111 detect the peak value of the excitation current and the induced signal VRs, respectively, as described above.

  When the detected induction signal VRs exceeds the first reference threshold voltage Vcomp1, that is, when it is determined that the stepping motor 105 has rotated (step S505), the control circuit 103 determines whether the count value PN has reached a predetermined number of times. That is, it is determined whether or not the peak value of the excitation current has been detected a predetermined number of times (step S506). In an analog electronic timepiece, when significant wear of the train wheel occurs in some cases, a sudden load increase occurs periodically (load increase / decrease period), and the rotational speed of the rotor 202 may be reduced. It is possible to reliably detect load fluctuations by setting the period for performing the number of times (in other words, the product of the detection period of the peak value of the excitation current and the predetermined number of times) to be longer than the load increase / decrease period. become.

When determining that the peak value has been detected a predetermined number of times in processing step S506, the control circuit 103 determines that at least one of the peak values of the excitation current detected the predetermined number of times exceeds the reference threshold current Pcomp (step S507). ), It is determined that the load of the stepping motor 105 has become larger than the predetermined value, the drive pulse is changed from the main drive pulse P1 to the load drive pulse Pf (step S508), and the mode is shifted to the load mode.
If the control circuit 103 determines in step S507 that none of the peak values of the excitation current detected a predetermined number of times exceeds the reference threshold current Pcomp, a large load such that the load of the stepping motor 105 exceeds the predetermined value. It is determined that the load is not normal, that is, a normal load, and the mode is shifted to the normal mode.
If the control circuit 103 determines in the processing step S506 that the count value PN has not reached the predetermined number of times, that is, the peak value of the excitation current has not been detected a predetermined number of times, the control circuit 103 returns to the processing step S501.

  If the induced signal VRs does not exceed the reference threshold voltage Vcomp in processing step S505, that is, if it is determined that the stepping motor 105 has not rotated, the control circuit 103 controls the drive pulse selection circuit 104 to perform correction. The stepping motor 105 is rotationally driven by the drive pulse P2 (step S509). Thereby, the stepping motor 105 is forcibly rotated. Next, the control circuit 103 resets the count value PN to 0 (step S510), and returns to the processing step S501.

  As described above, during the drive with the normal main drive pulse P1, the mode is switched to the periodic load detection mode at a predetermined timing set in advance, and in parallel with the detection of the induced signal VRs, the channel of the MOS transistor The peak value of the excitation current flowing through the drive coil 209 is detected using a voltage drop based on the excitation current generated in the impedance. When the peak value of the excitation current is detected a predetermined number of times (a value equal to or greater than the load generation period) and at least one excitation current detection value exceeds the reference threshold current Pcomp, a periodic load is generated. Therefore, the drive pulse is changed from the main drive pulse P1 to the load drive pulse Pf. Thereby, even when a large load is generated, it is possible to accurately detect the load condition and switch to an appropriate drive pulse.

In the load mode in which a load exceeding a predetermined value is rotationally driven, as shown in FIG. 6, the control circuit 103 resets the number of times of detection of rotation (count value FN) to 0 (step S601).
Next, the control circuit 103 controls the drive pulse selection circuit 104 to rotationally drive the stepping motor 105 with the load drive pulse Pf (step S602), and adds 1 to the count value FN (step S603).
When the detected induction signal VRs exceeds the reference threshold voltage Vcomp, that is, when it is determined that the stepping motor 105 has rotated (step S604), the control circuit 103 determines whether or not the count value FN has reached a predetermined number of times. Then, it is determined whether or not it has been continuously rotated a predetermined number of times without becoming non-rotating in the load mode (step S605).
The control circuit 103 returns to the normal mode when it is determined in the processing step S605 whether or not the count value FN has reached a predetermined number of times, that is, when it has been continuously rotated a predetermined number of times without becoming non-rotating in the load mode. If it is determined that the predetermined number of times has not been reached, the process returns to step S602.

If the induced signal VRs does not exceed the reference threshold voltage Vcomp in processing step S604, that is, if it is determined that the stepping motor 105 is not rotating, the control circuit 103 returns to processing step S601 and sets the count value FN to 0. Reset to.
In this way, after switching to the load driving pulse Pf, when it is determined that the motor has continuously rotated a predetermined number of times, it is returned to the main driving pulse P1. Therefore, since the drive pulse is returned to the main drive pulse P1 in the normal mode when it rotates stably a predetermined number of times, a change operation that reduces power waste is possible.

As described above, the stepping motor control circuit according to the first embodiment of the present invention detects the induced signal VRs generated by the rotation of the rotor 202 of the stepping motor 105, and the induced signal VRs and a predetermined reference threshold voltage. A rotation detection circuit 111 that detects the rotation state of the stepping motor 105 by comparing with Vcomp, a main drive pulse P1 that is driven at normal time, a load drive pulse Pf having a larger energy than the main drive pulse P1, and a load drive pulse Pf Control means for controlling the rotation of the stepping motor 105 by selecting a driving pulse corresponding to the rotation state of the stepping motor 105 from among a plurality of types of driving pulses including the correction driving pulse P 2 having a larger energy than the rotation of the stepping motor 105. Excitation current flowing through the stepping motor 105 by control And a current detection circuit 112 for detecting, when the current detection circuit 112 detects the peak value of the excitation current exceeding the predetermined value Pcom, the control means selects the drive pulse Pf for load and controls the rotation of the stepping motor 105. It is characterized by doing.
Accordingly, it is possible to accurately detect the load state of the stepping motor 105 and select an appropriate drive pulse, and thus it is possible to prevent energy waste.
In addition, even when a periodic load is permanently generated, it is possible to suppress an excessive increase in power consumption due to frequent driving by the correction driving pulse P2. Moreover, when using a battery as a power supply, the fall of battery power can be suppressed to the minimum.

Here, the current detection circuit 112 continuously detects the excitation current a predetermined number of times longer than the load fluctuation period, and the control means detects at least one of the detected peak values of the excitation current exceeding the predetermined value. When it is determined that the load driving pulse Pf is selected, the stepping motor 105 can be rotationally controlled.
The control means can be configured to return to the main drive pulse P1 and control the rotation when the stepping motor 105 can be continuously rotated a predetermined number of times by the load drive pulse Pf.
Further, the current detection circuit 112 can be configured to detect an excitation current when a predetermined time has elapsed after the start of driving by the main drive pulse.

In addition, the analog electronic timepiece according to the first embodiment includes an analog electronic timepiece having a stepping motor 105 that rotationally drives a time hand (hour hand 107, minute hand 108, second hand 110) and a stepping motor control circuit that controls the stepping motor 105. In the electronic timepiece, the stepping motor control circuit is used as the stepping motor control circuit.
Accordingly, it is possible to accurately detect the load condition of the stepping motor and select an appropriate drive pulse, and thus it is possible to provide an analog electronic timepiece that can prevent waste of energy. .

Next, a stepping motor control circuit and an analog electronic timepiece according to a second embodiment of the invention will be described.
FIG. 8 is a block diagram of an analog electronic timepiece using the stepping motor control circuit according to the second embodiment of the present invention, and shows an example of an analog electronic wristwatch.
In the second embodiment, a detection interval determination circuit 113 that detects in which interval the rotation detection circuit 111 detects the induced signal VRs exceeding the reference threshold voltage Vcomp is provided.

In the second embodiment, as the drive pulses, a plurality of types of main drive pulses P1 having different energy from each other, a load drive pulse Pf and a load drive pulse Pf having higher energy than the main drive pulses P1. A plurality of types of drive pulses including the correction drive pulse P2 having a larger energy than that are used.
The rotation detection circuit 111, the detection section determination circuit 113, and the control circuit 103 constitute an example of a rotation detection unit.

FIG. 9 is a timing chart when the stepping motor 105 is driven by the main drive pulse P1 in the second embodiment of the present invention, and shows the relationship between the energy of the drive pulse with respect to the load, the rotation position of the rotor 202, and the rotation status. The pattern to represent is also shown.
In FIG. 9, P1 represents the main drive pulse P1 and represents a region where the rotor 202 is rotationally driven by the main drive pulse P1, and a to e represent the rotor 202 driven by free vibration after the main drive pulse P1 is stopped. This is an area representing a rotational position.

A predetermined time immediately 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 immediately after driving with the main drive pulse P1 is divided into a plurality of sections (three sections T1 to T3 in the present embodiment). In the present embodiment, there is no mask section that is a period during which no induced signal VRs is detected.
When the XY coordinate space in which the main magnetic pole A of the rotor 202 is located by rotation of the rotor 202 is divided into the first quadrant I to the fourth quadrant IV, the first section T1 to the third section T3 are as follows. Can be represented.

  That is, in the normal drive state, the first section T1 is a section for determining the forward rotation state of the rotor 202 and the first section for determining the first reverse rotation state in the third quadrant III of the space centered on the rotor 202. The second section T2 is a section for determining the first reverse rotation state of the rotor 202 in the third quadrant III, and 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. is there. Here, the normal drive is a state in which a load driven at normal time can be normally driven by the main drive pulse P1, and in this embodiment, the time hand (hour hand 107, minute hand 108, second hand 110) is used as a load. The state in which normal driving can be performed with the driving pulse P1 is normal driving.

  Further, in a state where the driving energy is slightly smaller than the normal driving (slightly low energy state), the first section T1 is in the forward rotation state of the rotor 202 in the second quadrant II and the first rotation of the rotor 202 in the third quadrant III. The second section T2 is a section for determining the forward rotation situation in the forward direction, the second section T2 is a section for determining the first forward rotation situation and the first reverse rotation situation of the rotor 202 in the third quadrant III, and the third section T3 is the third section T3. This is a section for determining the rotation state after the first reverse rotation of the rotor 202 in the quadrant III.

Vcomp is a reference threshold voltage for determining the voltage level of the induced signal VRs generated by the stepping motor 105. When the rotor 202 performs a certain fast operation such as when the stepping motor 105 rotates, the induced signal When VRs exceeds the reference threshold voltage Vcomp and the rotor 202 does not perform a certain fast operation, such as when it does not rotate, the reference threshold voltage Vcomp is set so that the induced signal VRs does not exceed the reference threshold voltage Vcomp. Is set.
For example, in FIG. 9, in the stepping motor control circuit according to the present embodiment, in the normal driving state, the induced signal VRs generated in the region b is detected in the first section T1, and the induced signal VRs generated in the region c is The induced signal VRs detected after the first section T1 and the second section T2 and generated after the region c is detected in the third section T3.

  The determination value is “1” when the rotation detection circuit 111 detects the induced signal VRs exceeding the reference threshold voltage Vcomp, and the determination value when the rotation detection circuit 110 cannot detect the induced signal VRs exceeding the reference threshold voltage Vcomp. When “0” is set, in the example of normal driving in FIG. 9, (0, 1, 0) is represented as a pattern (0, 1, 0) representing the rotation state (the determination value of the first section, the determination value of the second section, the determination value of the third section). Is obtained. In this case, the control circuit 103 determines that the drive energy is sufficient, and when the stepping motor 105 can be continuously rotated a predetermined number of times by the main drive pulse P1, the drive energy is reduced by one rank (pulse down). The pulse control is performed as follows.

FIG. 10 is a determination chart summarizing the operation of the second embodiment. In FIG. 10, as described above, the determination value “1” is obtained when the induced signal VRs exceeding the reference threshold voltage Vcomp is detected, and the determination value “0” is detected when the induced signal VRs exceeding the reference threshold voltage Vcomp is not detected. ". “1/0” represents that the determination value may be “1” or “0”.
As shown in FIG. 10, the rotation detection circuit 111 detects the presence / absence of the induced signal VRs exceeding the reference threshold voltage Vcomp, and the control is performed based on the pattern in which the detection interval determination circuit 113 determines the detection timing of the induced signal VRs. With reference to the determination chart of FIG. 10 stored in the circuit 103, the control circuit 103 and the drive pulse selection circuit 104 perform drive pulse control, which will be described later, such as pulse-up or pulse-down of the main drive pulse P1 or drive by the correction drive pulse P2. To control the rotation of the stepping motor 105.

For example, in the case of the pattern (1/0, 0, 0), the control circuit 103 determines that the stepping motor 105 is not rotating (non-rotating) and drives the stepping motor 105 with the correction driving pulse P2. After controlling the drive pulse selection circuit 104, the drive pulse selection circuit 104 is controlled so as to change to the main drive pulse P1 that is upgraded by one rank in the next drive.
In the case of the pattern (1/0, 0, 1), the control circuit 103 rotates the stepping motor 105, but the drive energy is considerably low with respect to the load, and there is a possibility that the control circuit 103 may not rotate at the next drive. The drive pulse selection circuit 104 is controlled so as to change to the main drive pulse P1 that has been upgraded by one rank at the time of the next drive in advance without performing the drive by the correction drive pulse P2.

In the case of the pattern (1, 1, 1/0), the control circuit 103 determines that the stepping motor 105 rotates and that the drive energy is slightly lower than the load, and does not change the main drive pulse P1 at the next drive. The drive pulse selection circuit 104 is controlled so as to be driven at a time.
In the case of the pattern (0, 1, 1/0), the control circuit 103 determines that the driving energy is appropriate for the load, and the main driving pulse P1 is not changed for the time being. When the stepping motor 105 can be continuously rotated a number of times, the drive pulse selection circuit 104 is controlled so as to change to the main drive pulse P1 down by one rank and drive it.

FIGS. 11 to 13 are flowcharts showing operations of the stepping motor control circuit and the analog electronic timepiece according to the second embodiment, and are mainly flowcharts showing processing of the control circuit 103.
Hereinafter, with reference to FIGS. 2, 3, and 7 to 13, the second embodiment will be described in detail with respect to portions that are different from the first embodiment.
First, in the normal mode, the control circuit 103 sets the rank n of the main drive pulse P1 to rank 1 of the lowest energy rank, and resets the count value N of the internal counter of the control circuit 103 to 0 (step S101 in FIG. 11). ). Next, the control circuit 103 sets the main drive pulse P1 to the set main drive pulse P1n of rank n (here, n = 1) (step S102), and the stepping motor 105 is rotationally driven by the main drive pulse P1n. Thus, a control signal is output to the drive pulse selection circuit 104 (step S103).

In response to the control signal from the control circuit 103, the drive pulse selection circuit 104 rotationally drives the stepping motor 105 with the main drive pulse P1n. The stepping motor 105 is rotated by the main drive pulse P1n, and performs driving of the time hand (hour hand 107, minute hand 108, second hand 110) of the analog display unit 106 and date feed driving of the calendar display unit 109.
The rotation detection circuit 111 detects an induced signal VRs exceeding the reference threshold voltage Vcomp generated by the rotation driving of the stepping motor 105 in the detection section T every time driving by the main drive pulse P1n is performed. The detection section determination circuit 113 determines to which section T1 to T3 the induced signal VRs exceeding the reference threshold voltage Vcomp detected by the rotation detection circuit 111 belongs.

When the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is not detected within the first section T1 (the pattern is (0, x, x), provided that the determination value is used). “X” means whether the determination value is “1” or “0”.) (Step S104), whether or not the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the second section T2. Is determined (step S112).
The control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp has not been detected in the second section T2 in the processing step S112 (the case where the pattern is (0, 0, x)). Then, it is determined whether or not the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the third section T3 (step S108).

In the processing step S108, the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp has not been detected in the third section T3 (the pattern is (x, 0, 0)). ) Since it is non-rotating, the stepping motor 105 is driven by the correction drive pulse P2 having the same polarity as the main drive pulse P1n in the processing step S103 (step S110), and then the rank n of the main drive pulse P1n is increased by one rank. The main drive pulse P1 (n + 1) is changed and the count value N is reset to 0 (step S111).
Next, the control circuit 103 determines whether or not the periodic load detection period has arrived (step S107). If it is determined that the periodic load detection period has arrived, the control circuit 103 shifts to the detection mode, and the periodic load detection period arrives. If it is determined that the process has not been performed, the process returns to step S103.

When the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the third section T3 in the processing step S108 (when the pattern is (x, 0, 1)), the control circuit 103 rotates. However, the energy is considerably low, the rank n of the main drive pulse P1n is increased by 1 and changed to the main drive pulse P1 (n + 1), and the count value N is reset to 0 (step S109). The process proceeds to processing step S107.
When the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the second section T2 in the processing step S112 (when the pattern is (0, 1, x)), the total is calculated. 1 is added to the numerical value N (step S113).
The control circuit 103 determines whether or not the count value N has reached a predetermined value (in other words, whether or not driving with a pattern of (0, 1, x) has been performed a predetermined number of times) (step S114). If the predetermined value has been reached, the rank n of the main drive pulse P1n is lowered by 1 and the count value N is reset to 0, and the process proceeds to processing step 107. If the count value N has not reached the predetermined value, Immediately moves to processing step S107.

On the other hand, if the control circuit 103 determines in step S104 that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the first interval T1, the control circuit 103 determines the induced signal VRs exceeding the reference threshold voltage Vcomp in the second interval T2. If not detected, the process proceeds to step S108 (step S105).
When the control circuit 103 determines that the induced signal VRs exceeding the reference threshold voltage Vcomp is detected in the second section T2 in the processing step S105 (when the pattern is (1, 1, x)), the total is calculated. The numerical value N is reset to 0 and the process proceeds to processing step S107 (step S106).

In the detection mode, as shown in FIG. 12, the control circuit 103 controls the drive pulse selection circuit 104 to drive the stepping motor with the main drive pulse P1n (step S201), and adds 1 to the count value PN (step S502). ).
Thereafter, the control circuit 103 performs the same processing as in FIG. 5, and when it is determined that at least one of the peak values of the excitation current detected a predetermined number of times exceeds the reference threshold current Pcomp (step S507), the stepping motor 105 Is determined to be larger than the predetermined value, the drive pulse is changed from the main drive pulse P1n to the load drive pulse Pf (step S508), and the mode is shifted to the load mode.

If the control circuit 103 determines in step S507 that none of the peak values of the plurality of excitation currents exceeds the reference threshold current Pcomp, the control circuit 103 determines that the load of the stepping motor 105 is equal to or less than a predetermined value. Enter mode. Thereby, even when a large load is generated, it is possible to accurately detect the load condition and switch to an appropriate drive pulse.
In the load mode in which a load exceeding a predetermined value is rotationally driven, as shown in FIG. 13, the control circuit 103 resets the number of times of detection of rotation (count value FN) to 0 (step S601), and a drive pulse selection circuit 104 is controlled to rotate the stepping motor 105 with the load driving pulse Pf (step S602).

The control circuit 103 determines that the induced signal VRs detected by the rotation detection circuit 111 within the first detection section T1 does not exceed the reference threshold voltage Vcomp (in the case of the pattern (0, x, x)). (Step S301), it is determined whether or not the induced signal VRs detected in the second detection section T2 exceeds the reference threshold voltage Vcomp (Step S302).
When it is determined that the induced signal VRs detected in the second detection section T2 exceeds the reference threshold voltage Vcomp in the processing step S302 (in the case of the pattern (0, 1, x)), the control circuit 103 is normal. Since the energy is in the normal drive state, 1 is added to the count value FN (step S603).

Next, when it is determined that the count value FN has reached the predetermined value, the control circuit 103 determines that the rotation has been normally performed a predetermined number of times by the load drive pulse Pf, and shifts to the normal mode (step S605). . As a result, the mode shifts to the normal mode after the driving state in the load mode is stabilized, so that stable mode transition is possible.
When determining that the count value FN has not reached the predetermined value in the processing step S605, the control circuit 103 determines that the rotation has not been normally performed continuously for a predetermined number of times by the load driving pulse Pf, and returns to the processing step S301. Repeat the above process.
The control circuit 103 detects that the induced signal VRs detected in the second detection interval T2 in the processing step S302 does not exceed the reference threshold voltage Vcomp, or detected in the first detection interval T1 in the processing step S301. When it is determined that the induced signal VRs exceeds the reference threshold voltage Vcomp, the process returns to the processing step S601 and the above process is repeated.

As described above, according to the second embodiment of the present invention, the induced signal VRs generated by the rotation of the rotor 202 of the stepping motor 105 is detected, and the induced signal VRs is compared with a predetermined reference threshold voltage Vcomp. Then, a rotation detection circuit 111 and a detection interval determination circuit 113 for detecting the rotation state of the stepping motor 105, a plurality of types of main drive pulses P1 that are normally driven, a load drive pulse Pf having a larger energy than the main drive pulse P1, Control means for controlling the rotation of the stepping motor 105 by selecting a driving pulse corresponding to the rotation state of the stepping motor 105 from a plurality of types of driving pulses including the correction driving pulse P2 having energy larger than that of the load driving pulse Pf; It flows to the stepping motor 105 by the rotation control of the stepping motor 105 And a current detection circuit 112 for detecting a magnetic current. When the current detection circuit 112 detects a peak value of the excitation current exceeding the predetermined value Pcomp, the control means selects the load drive pulse Pf to select the stepping motor 105. It is characterized by controlling rotation.
Therefore, not only the same effects as in the first embodiment are obtained, but also excessive power consumption due to unnecessary rank increase of the main drive pulse P1 is suppressed even when a periodic load fluctuation occurs permanently. There is an effect that it becomes possible.

Next, a third embodiment of the present invention will be described.
The block diagram in the third embodiment of the present invention is the same as FIG.
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 of each electronic circuit element to be configured, control of change of drive pulse, and the like, and selects a drive pulse from a plurality of drive pulses for motor rotation drive based on a control signal from the control circuit 103 A driving pulse selection circuit 104 to output, a stepping motor 105 that is rotationally driven by a driving pulse from the driving pulse selection circuit 104, and a time hand that is rotationally driven by the stepping motor 105 to display time (in the example of FIG. 1, hour hand 107, An analog display unit 106 having a minute hand 108 and a second hand 110) and a calendar display unit 109 is provided.

Further, the analog electronic timepiece detects an induced signal VRs that indicates the rotation state of the stepping motor 105, and outputs a rotation detection signal that indicates whether or not the induced signal VRs exceeds a predetermined reference threshold voltage Vcomp. When the stepping motor 105 is rotationally driven by the drive pulse, the excitation current flowing through the drive coil is detected, and a current detection signal indicating whether the peak value of the excitation current exceeds a predetermined reference threshold current Pcomp is output. The current detection circuit 112 is provided.
A plurality of types of voltages are prepared as the reference threshold voltage Vcomp. In the present embodiment, as the reference threshold voltage, a first reference threshold voltage Vcomp1 (first voltage) having a predetermined voltage and a predetermined voltage smaller than the first reference threshold voltage Vcomp1 (for example, the first reference threshold voltage Vcomp1). A second reference threshold voltage Vcomp2 (second voltage) is prepared.

The first reference threshold voltage Vcomp1 is a reference threshold voltage used for driving in a normal driving state (normal mode; for example, a state in which the time hand is driven), and the second reference threshold voltage Vcomp2 is a constant load value. Is a reference threshold voltage used for driving exceeding the value (load mode; for example, when the load on the train wheel is increased or when the calendar display unit 109 performs daily feed driving).
In the normal driving state, when the stepping motor 105 rotates, the rotation detection circuit 111 detects the induced signal VRs exceeding the reference threshold voltage Vcomp1, and when the motor 105 does not rotate, the rotation detection circuit 111 performs the reference. The reference threshold voltage Vcomp1 is set so as not to detect the induced signal VRs exceeding the threshold voltage Vcomp1.
In the load state, when the stepping motor 105 rotates, the rotation detection circuit 111 detects the induced signal VRs exceeding the reference threshold voltage Vcomp2, and when the motor 105 does not rotate, the rotation detection circuit 111 performs the reference. The reference threshold voltage Vcomp2 is set so as not to detect the induced signal VRs exceeding the threshold voltage Vcomp2.

The current detection circuit 112 detects an excitation current that flows through the drive coil when the stepping motor 105 is driven to rotate by a drive pulse, and indicates whether the peak value of the excitation current exceeds a predetermined reference threshold current Pcomp. Output a signal. The magnitude of the peak value of the exciting current changes corresponding to the magnitude of the load that the stepping motor 105 rotates. When the peak value exceeds the reference threshold current Pcomp, it indicates that the load exceeds the predetermined value.
In the present embodiment, as an example of the load, an explanation is given of an example in which significant wear of the train wheel partially occurs and a load that periodically exceeds a predetermined value (periodic load) is generated. It is not limited.

  When it is determined that the current detection circuit 112 does not detect the peak value of the excitation current exceeding the reference threshold current Pcomp based on the current detection signal, the control circuit 103 determines that the load does not exceed the predetermined value. Thus, the reference threshold voltage Vcomp for the rotation detection circuit 111 is set to the first reference threshold voltage Vcomp1. On the other hand, when the control circuit 103 determines that the current detection circuit 112 has detected the peak of the excitation current exceeding the reference threshold current Pcomp based on the current detection signal, the load has increased beyond a predetermined value. Determination is made to set the reference threshold voltage Vcomp for the rotation detection circuit 111 to the second reference threshold voltage Vcomp2.

The rotation detection circuit 111 uses the reference threshold voltage Vcomp set by the control circuit 103 to indicate whether the induced signal VRs of the stepping motor 105 exceeds the reference threshold voltage Vcomp (in other words, the stepping motor A rotation detection signal (representing the rotation state 105) is output to the control circuit 103.
The control circuit 103 determines whether or not the stepping motor 105 has rotated based on the rotation detection signal. If it is determined that the stepping motor 105 has not rotated, the control circuit 103 is forcibly forced by the correction drive pulse P2 having higher energy than the main drive pulse P1. The drive pulse selection circuit 104 is controlled to rotate. When the load increases and is set to the second reference threshold value Vcomp2, the load is large, so that the main drive pulse (load drive pulse) Pn having higher energy than the main drive pulse P1 is driven. May be.

  Here, the oscillation circuit 101 and the frequency divider circuit 102 constitute an example of a signal generation unit, and the analog display unit 106 constitutes an example of a display unit. The rotation detection circuit 111 and the control circuit 103 constitute an example of rotation detection means, and the current detection circuit 112 constitutes an example of current detection means. The oscillation circuit 101, the frequency divider circuit 102, the control circuit 103, and the drive pulse selection circuit 104 constitute an example of a control unit.

FIG. 14 is a configuration diagram of a stepping motor 105 common to the third and sixth embodiments of the present invention, and shows an example of a time stepping motor generally used in an analog electronic timepiece.
In FIG. 14, a stepping motor 105 is wound around 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 magnetic core 208. A rotated drive coil 209 is provided. When the stepping motor 105 is used for an analog electronic timepiece, the stator 201 and the magnetic core 208 are fixed to a base plate (not shown) by screws or caulking (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 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 so as not to be magnetically saturated by the magnetic flux of the rotor 202 but to be magnetically saturated and to increase the magnetic resistance when excited by flowing an exciting current through the coil 209. 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 drive coil 209 is not excited, the rotor 202 is positioned corresponding to the positioning portion as shown in FIG. 14, 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 stable stationary position (a position that forms an angle θ0 with the direction X of the magnetic flux flowing through the stator 201) orthogonal to the minute.
Now, a rectangular-wave drive pulse of one polarity is supplied from the drive pulse selection circuit 104 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 the exciting current i flows in the direction of the arrow in FIG. 14, 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. 14 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 at the stable stationary position at the angle θ1 position.

  Next, the drive pulse selection circuit 104 supplies a drive pulse with a reverse polarity rectangular wave to the terminals OUT1 and OUT2 of the drive coil 209 (the first terminal OUT1 side is set to a negative polarity so as to have a reverse polarity to the drive). When the exciting current i flows in the direction opposite to the arrow in FIG. 14, a magnetic flux is generated in the stator 201 in the direction indicated by the broken line. 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 the angle θ0 is stabilized. Stops stably at a stationary position.

Thereafter, by supplying signals with different polarities (alternating signals) to the drive coil 209 in this way, the above operation is repeated, and the rotor 202 is continuously rotated 180 degrees in the direction of the solid arrow. It is configured to be able to.
In this embodiment, as will be described later, the drive pulse has a larger drive energy and a larger load than the main drive pulse P1 and the main drive pulse P1, which are used for normal driving capable of operating the load normally, as will be described later. The correction drive pulse P2 used for driving when the motor 105 cannot be rotated uses the load drive pulse Pn having a drive energy larger than that of the main drive pulse P1 in order to reliably rotate the stepping motor 105 when the load is large. Yes. The main drive pulses P1, Pn, and P2 are drive pulses having different energy. The load drive pulse Pn is not always necessary, and the main drive pulse P1 may be used when the stepping motor 105 can be rotated even when the load is large.

The third embodiment also includes the drive pulse selection circuit 104, the rotation detection circuit 111, and the current detection circuit 112 as shown in FIG.
As described with reference to FIG. 3, the N channel MOS transistors Q 1 and Q 2, the P channel MOS transistors Q 3 and Q 4, and the switch control circuit 303 are components of the drive pulse selection circuit 104. A drive coil 209 of the stepping motor 105 is connected between the source connection point of the transistors Q1 and Q3 and the source connection point of the transistors Q2 and Q4.

P-channel MOS transistors Q3 to Q6, a detection resistor 301 as an example of a detection element connected in series to the transistor Q5, a detection resistor 302 as an example of a detection element connected in series to the transistor Q6, a switch control circuit 303, and a comparator Reference numeral 304 denotes a component of the rotation detection circuit 111. The detection resistors 301 and 302 are detection elements used for rotation detection, and generate an induction signal VRs when rotation is detected.
Transistors Q3 and Q4 are components of the current detection circuit 112. When the stepping motor 105 is rotationally driven, an exciting current is passed through the drive coil 209. The voltage generated in the channel impedance of the transistor Q3 or Q4 by the exciting current becomes a value corresponding to the exciting current. The current detection circuit 112 detects whether or not the peak value of the excitation current exceeds the reference threshold current Pcomp by comparing the voltage generated in the channel impedance with a predetermined reference voltage, and outputs a current detection signal indicating this. Output.

The gates of the transistors Q1 to Q6 are connected to the switch control circuit 103. A connection point OUT2 between the detection resistor 301 and the drive coil 209 and a connection point OUT1 between the detection resistor 302 and the drive coil 209 are connected to an input portion of the comparator 304. In addition, the first reference threshold voltage Vcomp1 or the second reference threshold voltage Vcomp2 is input to the input unit of the comparator 304 when the rotation of the stepping motor 105 is detected.
When the stepping motor 105 is rotationally driven, the switch control circuit 303 simultaneously turns on the transistors Q2 and Q3 in response to the rotational drive control pulse Vi corresponding to the drive pulse supplied from the control circuit 103, or By simultaneously turning on the transistors Q1 and Q4, an exciting current is supplied to the drive coil 209 in the forward direction or the reverse direction, thereby driving the stepping motor 105 to rotate.

At this time, as shown in FIG. 7, a current corresponding to the magnitude of the load flows through the drive coil 209. In FIG. 7, when driven by the main drive pulse P1 (pulse width is from time t0 to time t2), an exciting current having a waveform corresponding to the magnitude of the load flows. The excitation current waveform has a peak (maximum value) immediately after the start of driving the main drive pulse P1, and then a valley (minimum value). Waveform 1 shows an excitation current waveform when the load is small, waveform 2 shows a medium load, waveform 3 shows an excitation current waveform when the load is larger than a predetermined value, and an excitation current value (peak value) at a valley (peak K) Fluctuates according to the magnitude of the load.
The current detection circuit 112 detects an excitation current value (peak value) at a peak detection time t1, that is, a peak K when a predetermined time (for example, 3 msec) has elapsed from the start of driving by the driving pulse P1. The peak value is a minimum value of the excitation current that appears after passing a mountain that occurs immediately after the start of driving with a drive pulse, and is the lowest current value in the predetermined period.

  When the load of the stepping motor 105 is not more than a predetermined value, as shown in waveforms 1 and 2, the peak value of the excitation current becomes not more than a predetermined reference current Pcomp at a predetermined time t1. On the other hand, when the load increases and exceeds a predetermined value, the peak value of the excitation current exceeds the reference current Pcomp as shown by the waveform 3. The current detection circuit 112 outputs a current detection signal indicating whether or not the peak value of the excitation current exceeds Pcomp. Specifically, the current detection circuit 112 compares the voltage generated in the channel impedance of the transistor Q3 or Q4 with a predetermined reference voltage when the exciting current flows through the transistor Q3 or the transistor Q4 in the on state, whereby It is detected whether or not the excitation current exceeds the reference threshold current Pcomp.

Based on the detection result of the current detection circuit 112, the reference threshold voltage Vcomp of the rotation detection circuit 111 is set to the first reference threshold voltage Vcomp1 or the second reference threshold voltage Vcomp2, and subsequently, in the rotation detection period. Rotation detection is performed.
In the rotation detection period, when detecting the induced signal VRs generated by the free vibration of the stepping motor 105 after the rotation drive, the switch control circuit 303 responds to the rotation detection control pulse Vi from the control circuit 103 in response to the transistors Q3, The on / off control of the transistor Q4 with a predetermined cycle with the Q6 turned on, or the on / off control of the transistor Q3 with a predetermined cycle with the transistors Q4 and Q5 turned on, causes an induced signal in the comparator 304 Detect VRs.

When the comparator 304 detects the induced signal VRs exceeding the set reference threshold voltage Vcomp among the induced signals VRs induced in the stepping motor 105 (in other words, the drive coil 209), the comparator 304 exceeds the set reference threshold voltage Vcomp. A detection signal Vs indicating that the signal VRs has been detected is output. When the control circuit 103 determines that the stepping motor 105 has rotated based on the detection signal, the control circuit 103 performs the next drive control without performing the drive by the correction drive pulse P2. If the control circuit 103 determines that the stepping motor 105 has not rotated based on the detection signal Vs, the control circuit 103 performs driving by the correction driving pulse P2 to forcibly rotate the stepping motor 105.
FIG. 15 is a flowchart of a stepping motor control circuit common to the third and sixth embodiments of the present invention.
FIG. 16 is a flowchart of the stepping motor control circuit according to the third embodiment of the present invention.

Hereinafter, the operation of the third embodiment will be described in detail with reference to FIGS. 1, 3, 6, 7, and 14 to 16.
First, the operation in the normal mode in which the time measurement operation is performed and the time is displayed will be described.
The oscillating circuit 101 generates a reference clock signal having a predetermined frequency, and the frequency dividing circuit 102 divides the signal generated by the oscillating circuit 101 and outputs a clock signal serving as a time reference to the control circuit 103 at predetermined intervals.
The control circuit 103 sets the reference threshold voltage Vcomp to normal (the first reference threshold voltage Vcomp1 described above), and resets the count value PN in the control circuit 103 to 0 (step S1501 in FIG. 15). Counts the clock signal and performs the timekeeping operation. Here, the count value PN is a count value for counting the number of times the excitation current is detected.

The control circuit 103 outputs a control signal so as to rotationally drive the stepping motor 105 with the main drive pulse P1 having a predetermined energy every time the clock signal is counted (step S402). In response to the control signal from the control circuit 103, the drive pulse selection circuit 104 rotationally drives the stepping motor 105 with the main drive pulse P1. The stepping motor 105 is rotated by the main drive pulse P1 to perform the hand movement driving of the time hand (the hour hand 107, the minute hand 108, the second hand 110) of the analog display unit 106 and the date feed driving of the calendar display unit 109.
In this manner, the main hand driving pulse P1 performs the hand movement operation (normal hand movement) for driving the time hands 107 to 108, 110 to rotate forward at a predetermined hand movement interval (one second interval in the present embodiment). Then, the date display driving of the calendar display unit 109 is performed. As a result, the current time is displayed by the time hands 107, 108, and 110 of the analog display unit 106, and the date of the day is displayed by the calendar display unit 109.

Next, the control circuit 103 determines whether or not a periodic load detection period has arrived (step S403). The periodic load detection period indicates timing for detecting whether or not the load of the stepping motor 105 has periodically increased. The periodic load means a load that increases or decreases at a constant cycle, and includes, for example, a load increased due to wear of a train wheel and a calendar load.
If the control circuit 103 determines in step S403 that the periodic load detection period has arrived, the control circuit 103 shifts to a detection mode for detecting the excitation current of the stepping motor 105 and newly setting the reference threshold value Vcomp, When it is determined that the periodic load detection period has not arrived, the process returns to processing step S402.

In the detection mode, as shown in FIG. 16, the control circuit 103 controls the drive pulse selection circuit 104 to drive the stepping motor with the main drive pulse P1 (step S501), and adds 1 to the count value PN (step S502). ).
Next, the control circuit 103 causes the current detection circuit 112 to detect the peak value of the excitation current of the stepping motor 105 (step S503), and then causes the rotation detection circuit 111 to detect the induction signal VRs of the stepping motor 105 (step S504). . The current detection circuit 112 and the rotation detection circuit 111 each detect the peak value of the excitation current and the induced signal Vrs as described above.

  When the detected induction signal VRs exceeds the first reference threshold voltage Vcomp1, that is, when it is determined that the stepping motor 105 has rotated (step S505), the control circuit 103 determines whether the count value PN has reached a predetermined number of times. That is, it is determined whether or not the peak value of the excitation current has been detected a predetermined number of times (step S506). In an analog electronic timepiece, when there is a significant wear of the train wheel, a sudden load occurs periodically (load increase / decrease cycle), and the rotational speed of the rotor may be reduced. (In other words, by setting the product of the peak value detection cycle of the excitation current and the predetermined number of times) to be longer than the load increase / decrease cycle, it is possible to reliably detect the load fluctuation.

When the control circuit 103 determines that the peak value has been detected a predetermined number of times in processing step S506, the control circuit 103 determines that at least one of the peak values of the excitation current detected the predetermined number of times exceeds the reference threshold current Pcomp (step S507). ), It is determined that the load of the stepping motor 105 is larger than the predetermined value, and the rotation detection circuit 111 changes the reference threshold voltage Vcomp from the first reference threshold voltage Vcomp1 to the second reference threshold voltage Vcomp2 (step S1601). Transition to load mode.
If the control circuit 103 determines in step S507 that none of the peak values of the excitation current detected a predetermined number of times exceeds the reference threshold current Pcomp, a large load such that the load of the stepping motor 105 exceeds the predetermined value. That is, it is determined that the load is normal, and the mode is changed to the normal mode.
If the control circuit 103 determines in the processing step S506 that the count value PN has not reached the predetermined number of times, that is, the peak value of the excitation current has not been detected a predetermined number of times, the control circuit 103 returns to the processing step S501.

  The control circuit 103 controls the drive pulse selection circuit 104 when the induced signal VRs does not exceed the first reference threshold voltage Vcomp1 in processing step S505, that is, when it is determined that the stepping motor 105 has not rotated. Then, the stepping motor 105 is rotationally driven by the correction drive pulse P2 (step S509). Thereby, the stepping motor 105 is reliably rotated. Next, the control circuit 103 resets the count value PN to 0 (step S510), and returns to the processing step S501.

As described above, during the drive with the normal main drive pulse P1, the mode is switched to the periodic load detection mode at a predetermined timing set in advance, and in parallel with the detection of the induced signal VRs, the channel of the MOS transistor The peak value of the excitation current flowing through the drive coil 209 is detected using a voltage drop based on the excitation current generated in the impedance. When the peak value of the excitation current is detected a predetermined number of times (a value equal to or greater than the load generation period) and at least one excitation current detection value exceeds the reference threshold current Pcomp, a periodic load is generated. Therefore, the reference threshold voltage Vcomp is changed from the first reference threshold voltage Vcomp1 to the second reference threshold voltage Vcomp2. Thereby, even when a large load is generated, the rotation state can be accurately detected.
If the reference threshold voltage Vcomp is lowered, the induced signal VRs during non-rotation may be erroneously detected exceeding the reference threshold voltage Vcomp. However, if a large load exceeding a predetermined value is generated, the rotor 202 Since the rotation speed is low, the possibility of erroneous detection is low.

In the load mode in which the load exceeding the predetermined value is rotationally driven, as shown in FIG. 6, the control circuit 103 resets the number of times of rotation detection (count value FN) using the second threshold voltage Vcomp2 to 0 (step S601). ).
Next, the control circuit 103 controls the drive pulse selection circuit 104 to rotationally drive the stepping motor 105 with the load drive pulse Pn (step S602), and adds 1 to the count value FN (step S603).

When the detected induction signal VRs exceeds the second reference threshold voltage Vcomp2, that is, when it is determined that the stepping motor 105 has rotated (step S604), the control circuit 103 determines whether or not the count value FN has reached a predetermined number of times. That is, it is determined whether or not it has been continuously rotated a predetermined number of times without becoming non-rotating in the load mode (step S605).
The control circuit 103 returns to the normal mode when it is determined in the processing step S605 whether or not the count value FN has reached a predetermined number of times, that is, when it has been continuously rotated a predetermined number of times without becoming non-rotating in the load mode. If it is determined that the predetermined number of times has not been reached, the process returns to step S602.

If the induced signal VRs does not exceed the second reference threshold voltage Vcomp2 in processing step S604, that is, if it is determined that the stepping motor 105 is not rotating, the control circuit 103 returns to processing step S601 and count value FN. Is reset to 0.
In this way, after switching to the second reference threshold voltage Vcomp2, if it is determined that the motor has continuously rotated a predetermined number of times, the first reference threshold voltage Vcomp1 is restored. Therefore, since the reference threshold value Vcomp is returned to the reference threshold voltage in the normal mode when it rotates stably for a predetermined number of times, a stable change operation of the reference threshold voltage becomes possible.

  As described above, according to the third embodiment, the induced signal VRs generated by the rotation of the rotor 202 of the stepping motor 105 is detected, and the induced signal VRs is compared with a predetermined reference threshold voltage Vcomp. A rotation detection circuit 111 for detecting a rotation state of the stepping motor 105; a control means for selecting a drive pulse corresponding to the rotation state of the stepping motor 105 from a plurality of drive pulses; and controlling the rotation of the stepping motor 105; And a current detection circuit 112 that detects an exciting current flowing in the stepping motor 105 by the rotation control of 105, and a plurality of types of voltages (in this embodiment, the first reference threshold voltage Vcomp1, the second reference threshold voltage Vcomp). A reference threshold voltage Vcomp2) is prepared, and the rotation detection circuit 111 A reference threshold voltage Vcomp is changed in accordance with the magnitude of the excitation current detected by the current detection circuit 112.

Therefore, since the rotation of the stepping motor 105 can be accurately detected even when the load increases, unnecessary driving with the correction drive pulse P2 can be prevented, and waste of energy can be prevented.
In addition, even when a periodic load is generated permanently, a situation in which the level of the induced signal VRs is low or the generation is not detected with a delay occurs, so that the drive by the correction drive pulse P2 occurs. It is possible to suppress the occurrence of excessive power consumption due to frequent occurrence of. Moreover, when using a battery as a power supply, the fall of battery power can be suppressed to the minimum.

Here, as the plurality of types of reference threshold voltages, a predetermined first voltage (first reference threshold voltage Vcomp1) and a second voltage lower than the first voltage by a predetermined voltage (second reference threshold voltage Vcomp2) The rotation detection circuit 111 can be configured to change the reference threshold voltage Vcomp to the second voltage when the current detection circuit 112 detects an excitation current exceeding a predetermined value Pcomp.
Further, as the plurality of types of reference threshold voltages, a predetermined first voltage (first reference threshold voltage Vcomp1) and a second voltage (second reference threshold voltage Vcomp2) lower than the first reference voltage by a predetermined voltage. The rotation detection circuit 111 changes the reference threshold voltage Vcomp to the first voltage when the induced signal VRs exceeds the second voltage after changing the reference threshold voltage Vcomp to the second voltage. Can be configured to change.
The rotation detection circuit 111 changes the reference threshold voltage Vcomp to the first voltage when the induced signal VRs exceeds the second voltage continuously for a predetermined number of times after changing the reference threshold voltage Vcomp to the second voltage. Can be configured to change.

Further, according to the analog electronic timepiece according to the third embodiment, the stepping motor 105 that rotationally drives the time hands (the hour hand 107, the minute hand 108, and the second hand 110) and the stepping motor control circuit that controls the stepping motor 105 are provided. The analog electronic timepiece has the stepping motor control circuit as the stepping motor control circuit.
Therefore, since the rotation of the stepping motor 105 can be accurately detected even when the load increases, it is possible to prevent unnecessary driving of the time hand with the correction drive pulse, and to prevent waste of energy.

  In the third embodiment, the rotation state of the stepping motor 105 is determined based on whether or not the reference threshold voltage Vcomp is exceeded. However, the detection interval is divided into a plurality of intervals, and It is detected whether or not the reference threshold voltage Vcomp is exceeded (“1”) or not (“0”) in each section, and a pattern obtained by combining the detection results “1” and “0” in each section becomes a predetermined pattern. It may be configured to determine the rotation state depending on whether or not.

Next, a fourth embodiment of the present invention will be described.
FIG. 17 is a flowchart showing processing in a detection mode of the stepping motor control circuit and the analog electronic timepiece according to the fourth embodiment of the invention. The configuration and other processing of the fourth embodiment are the same as those of the first embodiment.
In the first embodiment, when it is determined that at least one of the peak values of the excitation current detected a predetermined number of times exceeds the reference threshold current Pcomp, the drive pulse is changed from the main drive pulse P1 to the load drive pulse Pf. Although it has shifted to the load mode ((steps S507 and S508 in FIG. 5), in the fourth embodiment, when it is determined that the excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number of times, The drive pulse is changed from the main drive pulse P1 to the load drive pulse Pf to shift to the load mode.

That is, in FIG. 17, when the control circuit 103 determines that the peak value of the excitation current has been detected a predetermined number of times in processing step S506, at least one of the peak values of the excitation current detected the predetermined number of times is the reference threshold current Pcomp. If it is determined that it exceeds (step S507), it is determined whether or not an excitation current exceeding the reference threshold current Pcomp has been detected a predetermined number of times (step S1701).
When the control circuit 103 determines that the excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number in processing step S1701, the control circuit 103 determines that the load of the stepping motor 105 has become larger than the predetermined value, and drives The pulse is changed from the main drive pulse P1 to the load drive pulse Pf (step S508), and the mode is shifted to the load mode.

If the control circuit 103 determines in step S1701 that the excitation current exceeding the reference threshold current Pcomp has not been detected a predetermined number of times, the control circuit 103 determines that the load of the stepping motor 105 is not greater than the predetermined value. To return to the normal mode.
According to the fourth embodiment, not only the same effect as in the first embodiment is obtained, but also when it is determined that the excitation current exceeding the reference threshold current Pcomp is detected more than a predetermined number of times. Therefore, it is possible to prevent switching to the load mode due to a sudden load that occurs very rarely, and to suppress the total current consumption.

Next, a fifth embodiment of the present invention will be described.
FIG. 18 is a flowchart showing processing in the detection mode of the stepping motor control circuit and the analog electronic timepiece according to the fifth embodiment of the invention. The configuration and other processing of the fifth embodiment are the same as those of the second embodiment.
Also in the fifth embodiment, as in the fourth embodiment, when it is determined that an excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number of times, the drive pulse is driven to the main drive. The pulse P1 is changed to the load drive pulse Pf so as to shift to the load mode.

That is, in FIG. 18, when the control circuit 103 determines in step S506 that the excitation current peak value has been detected a predetermined number of times, at least one of the excitation current peak values detected a predetermined number of times is the reference threshold current Pcomp. If it is determined that it exceeds (step S507), it is determined whether or not an excitation current exceeding the reference threshold current Pcomp has been detected a predetermined number of times (step S1701).
When the control circuit 103 determines that the excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number in processing step S1701, the control circuit 103 determines that the load of the stepping motor 105 has become larger than the predetermined value, and drives The pulse is changed from the main drive pulse P1 to the load drive pulse Pf (step S508), and the mode is shifted to the load mode.

  According to the fifth embodiment, when it is determined that not only the same effect as the second embodiment but also an excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number of times. Therefore, it is possible to prevent switching to the load mode due to a sudden load that occurs very rarely, and to suppress the total current consumption.

Next, a sixth embodiment of the present invention will be described.
FIG. 19 is a flowchart showing processing in the detection mode of the stepping motor control circuit and the analog electronic timepiece according to the sixth embodiment of the invention. The configuration and other processing of the sixth embodiment are the same as those of the third embodiment.
In the sixth embodiment, when it is determined that the excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number of times, the reference threshold voltage Vcomp is changed to the second voltage. .

That is, in FIG. 19, when the control circuit 103 determines in step S506 that the excitation current peak value has been detected a predetermined number of times, at least one of the excitation current peak values detected a predetermined number of times is the reference threshold current Pcomp. If it is determined that it exceeds (step S507), it is determined whether or not an excitation current exceeding the reference threshold current Pcomp has been detected a predetermined number of times (step S1701).
If the control circuit 103 determines in step S1701 that the excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number of times, the control circuit 103 determines that the load of the stepping motor 105 has become larger than the predetermined value, and detects rotation. The circuit 111 changes the reference threshold voltage Vcomp from the first reference threshold voltage Vcomp1 to the second reference threshold voltage Vcomp2 (step S1601), and shifts to the load mode.

  According to the sixth embodiment, not only has the same effect as the third embodiment, but also when it is determined that the excitation current exceeding the reference threshold current Pcomp has been detected more than a predetermined number of times. Therefore, it is possible to prevent switching to the load mode due to a sudden load that occurs very rarely, and to suppress the total current consumption.

In each of the above embodiments, in order to change the energy of each drive pulse P1, Pf, P2, the pulse width is different. However, the drive pulse is constituted by a plurality of comb-like pulses, and the comb-teeth shape is used. It is also possible to change the energy of the drive pulse by changing the number and duty of the pulses or changing the pulse voltage.
The present invention can also be applied to an analog electronic timepiece that does not have a calendar function.
Further, although an example of an electronic timepiece having a single motor has been described as an application example of a stepping motor, it can be applied to an electronic timepiece having a plurality of motors such as a chronograph timepiece and various electronic devices using the motor.

The stepping motor control circuit according to the present invention is applicable to various electronic devices that use the stepping motor.
In addition, the electronic timepiece according to the present invention includes various electronic electronic watches such as an analog electronic wristwatch with a calendar function, an analog electronic timepiece with a calendar function such as an analog electronic table clock with a calendar function, a chronograph timepiece, and an analog electronic timepiece without a calendar function. It can be applied to analog electronic watches.

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: Calendar display unit 110 ... Second hand 111 ... Rotation detection circuit 112 ... Current detection circuit 113 ... Detection section discrimination circuit 201 ... Stator 202 ... Rotor 203 ... Rotor accommodation Through holes 204, 205 for notches (notches)
206, 207 ... Notch (outer notch)
208 ... Magnetic core 209 ... Drive coils 210 and 211 ... Saturable part OUT1 ... First terminal OUT2 ... Second terminals Q1 to Q6 ... Transistors 301 and 302 ... Detection resistors 303 ... Switch control circuit 304 ... Comparator

Claims (10)

Rotation detecting means for detecting an induced signal generated by the rotation of the rotor of the stepping motor and comparing the induced signal with a predetermined reference threshold voltage to detect the rotation state of the stepping motor, and a main drive that is normally driven Drive pulse corresponding to the rotation state of the stepping motor among a plurality of types of drive pulses including a pulse, a load drive pulse having a higher energy than the main drive pulse, and a correction drive pulse having a higher energy than the load drive pulse Control means for controlling the rotation of the stepping motor by selecting the current, and current detection means for detecting an excitation current flowing in the stepping motor by the rotation control of the stepping motor,
A stepping motor control circuit, wherein when the current detection means detects a peak value of an excitation current exceeding a predetermined value, the control means selects a drive pulse for load and controls the rotation of the stepping motor. The current detection means detects the peak value of the excitation current a predetermined number of times continuously for longer than the load fluctuation period,
The control means selects the load drive pulse and controls the rotation of the stepping motor when it is determined that at least one of the detected peak values of the excitation current exceeds the predetermined value. Item 5. A stepping motor control circuit according to Item 1. The current detection means detects the peak value of the excitation current a predetermined number of times continuously for longer than the load fluctuation period,
2. The control unit according to claim 1, wherein when it is determined that an excitation current exceeding the predetermined value has been detected more than a predetermined number of times, the control unit selects the load drive pulse and controls the rotation of the stepping motor. The stepping motor control circuit described.   4. The control unit according to claim 1, wherein when the stepping motor can be continuously rotated a predetermined number of times by the load drive pulse, the control means returns to the main drive pulse to control the rotation. A stepping motor control circuit according to claim 1. A rotation detecting means for detecting an induced signal generated by rotation of the rotor of the stepping motor and comparing the induced signal with a predetermined reference threshold voltage to detect the rotation state of the stepping motor; and a plurality of drive pulses. Control means for selecting the driving pulse according to the rotation state of the stepping motor from the control means to control the rotation of the stepping motor, and current detection means for detecting the excitation current flowing through the stepping motor by the rotation control of the stepping motor. And
A plurality of types of voltages are prepared as the reference threshold voltage,
The stepping motor control circuit, wherein the rotation detecting means changes the reference threshold voltage according to the magnitude of the excitation current detected by the current detecting means. As the plurality of types of reference threshold voltages, a predetermined first voltage and a second voltage lower than the first voltage by a predetermined voltage are prepared,
6. The stepping motor control circuit according to claim 5, wherein the rotation detection unit changes the reference threshold voltage to the second voltage when the current detection unit detects an excitation current exceeding a predetermined value.   The rotation detection means changes the reference threshold voltage to the second voltage when the current detection means detects an excitation current exceeding a predetermined value exceeding a predetermined number of times. Stepping motor control circuit. As the plurality of types of reference threshold voltages, a predetermined first voltage and a second voltage lower than the first voltage by a predetermined voltage are prepared,
The rotation detecting means changes the reference threshold voltage to the first voltage when the induced signal exceeds the second voltage after changing the reference threshold voltage to the second voltage. A stepping motor control circuit according to claim 6 or 7.   The rotation detecting unit changes the reference threshold voltage to the first voltage when the induced signal exceeds the second voltage continuously for a predetermined number of times after changing the reference threshold voltage to the second voltage. 9. The stepping motor control circuit according to claim 8, wherein 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 9 as the stepping motor control circuit.

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