JP6590495B2 - Stepping motor control device - Google Patents

Description

The present invention relates to a control device for a stepping motor.

2. Description of the Related Art Conventionally, a stepping motor that includes two coils and is configured to be capable of forward and reverse rotation by appropriately applying a drive signal to the coils is known.
For example, Patent Document 1 discloses a stepping motor including a rotor having two poles and a stator having two main magnetic poles and one sub magnetic pole.
In a stepping motor, it is necessary for the rotor to rotate reliably at each step.

  Therefore, in general, in the drive control of the stepping motor, after applying a drive signal for rotating the rotor, a counter electromotive force (counter electromotive voltage) generated by damping when the rotor stops at a predetermined step angle is detected. Thus, it is determined whether or not the rotor has rotated (rotation detection of the rotor). If it is determined that the rotor has not rotated, a correction pulse is further applied to rotate the rotor. Yes.

Japanese Patent Publication No. 5-006440 (Fig. 1)

  However, in the case of a stepping motor having two coils, since the back electromotive force (back electromotive voltage) generated when the application of the drive signal is stopped after the drive signal is applied does not exceed a predetermined detectable level, the rotor The difference between when rotating and when not rotating was small, and it was extremely difficult to determine whether the rotor rotated. For this reason, there has been a problem that accurate rotation detection cannot be performed.

  In the case of a stepping motor having two coils, the reason why the back electromotive force (counter electromotive voltage) does not exceed a predetermined detectable level is that the magnetic flux generated from the rotor is distributed to the two coils. .

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a two-coil step motor capable of accurately detecting step rotation driving of a normal needle-operated rotor.

The drive control mechanism of the two-coil type step motor of the present invention adopts the configuration described below.
That is,
A rotor composed of a two-pole magnetized permanent magnet;
A first coil and a second coil for supplying magnetic force for rotating the rotor;
A stator having a rotor hole for accommodating the rotor, and for inducing magnetic force generated from the first coil and the second coil to the rotor;
A stepping motor control device comprising:
Includes a circuit portion and a rotation detecting circuit and drivers circuit, and a control unit for controlling the circuit unit,
The control unit includes a control circuit that controls a pulse generation circuit and a rotation detection signal generation circuit that outputs a rotation detection signal for detecting an operation state of the rotor ,
The pulse generation circuit generates a correction pulse stronger than the normal movement pulse together with the normal movement pulse,
The rotation detection circuit outputs the rotation detection signal from the rotation detection signal generation circuit to the driver circuit after the normal hand movement pulse is applied to the first coil and the second coil. at the timing of the good Ri rotation detecting period, wherein the normal rotation detecting a state where the first coil and the second coil is connected to the rotation detecting circuit, the timing is not said rotation detection period, said by the driver circuit A normal rotation pause state in which the first coil and the second coil are not connected to the rotation detection circuit;
Wherein the rotation detection signal generating circuit, and outputs a rotation detection signal Ru was intermittently repeated the forward hibernation and the normal rotation detecting state to the driver circuit,
The control unit detects a counter electromotive current due to free vibration of the rotor output from the rotation detection circuit , determines a rotation / non-rotation by observing a counter electromotive current before and after the rotor rotates 180 degrees, When it is detected that the rotor is not rotating, the correction pulse for rotating the rotor is output to the driver circuit, and when it is detected that the rotor is rotated, the correction pulse is output to the driver circuit. Control not to output , when the rotation is detected, the first coil and the second coil are connected in parallel,
The detection of the counter electromotive current uses a counter electromotive current obtained by superimposing a counter electromotive current generated in the first coil and a counter electromotive current generated in the second coil.

According to the above aspect of the present invention, since the back electromotive voltage generated from the magnetic flux of the rotor at the time of detecting rotation can be increased, stable rotation detection of the rotor is possible.

1 is an overall view of a motor unit in Embodiment 1. FIG. FIG. 3 is an enlarged view of a rotor periphery in the first embodiment. FIG. 5 is a diagram showing a change in the amount of magnetic flux with respect to the rotor position in the first embodiment. FIG. 5 is a diagram showing a change in counter electromotive current with respect to the rotor position in the first embodiment. FIG. 3 is a diagram showing changes in counter electromotive current during rotation in the first embodiment. FIG. 3 is a diagram showing a change in counter electromotive current during non-rotation in the first embodiment. 2 is a block diagram of a drive control mechanism in Embodiment 1. FIG. FIG. 3 is a circuit diagram of a circuit unit in the first embodiment. FIG. 3 is a pulse configuration diagram in the first embodiment. FIG. 3 is a diagram illustrating a switch state of a circuit unit in the first embodiment. FIG. 3 is a diagram illustrating a switch state of a circuit unit in the first embodiment. FIG. 3 is a diagram illustrating a switch state of a circuit unit in the first embodiment. FIG. 3 is a diagram illustrating a switch state of a circuit unit in the first embodiment. FIG. 3 is a diagram illustrating a switch state of a circuit unit in the first embodiment. FIG. 3 is a motor state transition diagram illustrating a rotation operation in normal rotation in the first embodiment. FIG. 3 is a motor state transition diagram illustrating a rotation operation in non-forward rotation in the first embodiment. FIG. 3 is a detection correlation diagram illustrating a correlation between a drive signal waveform during rotation and a back electromotive current in the first embodiment. FIG. 3 is a detection correlation diagram showing a correlation between a drive signal waveform and a back electromotive current during non-rotation in the first embodiment. FIG. 6 is a circuit diagram of a circuit unit in a first modification of the first embodiment. It is the figure which showed the back electromotive force change at the time of rotation in Embodiment 2. FIG. It is the figure which showed the back electromotive force change at the time of the non-rotation in Embodiment 2. FIG. 6 is a detection correlation diagram showing a correlation between a drive signal waveform during rotation and a counter electromotive current in Embodiment 2. FIG. 6 is a detection correlation diagram showing a correlation between a drive signal waveform and a back electromotive current during non-rotation in the second embodiment. 6 is a circuit diagram of a circuit unit in Embodiment 2. FIG. FIG. 6 is a diagram illustrating a switch state of a circuit unit in the second embodiment. FIG. 6 is a diagram illustrating a switch state of a circuit unit in the second embodiment.

[Description of Embodiment 1]
Embodiment 1 will be described with reference to the drawings. The first embodiment is based on the case where the present invention is applied to a timepiece, but the description and illustration are omitted for a structure not related to the invention, for example, a structural part of the timepiece such as a ground plate, a receptacle, and a pointer. .

  1A is an overall view of the motor unit, FIG. 1B is an enlarged view of the periphery of the rotor 101 of FIG. 1A and shows the rotation angle of the rotor 101, and w is the N of the rotor 101. The rotation angle, which is the angle at which the pole exists, is shown.

In FIG. 1A, 100 is a two-coil step motor, 101 is a rotor magnetized with two poles, N and S, and 102 is a stator having a rotor hole 1020 for housing the rotor 101. Reference numerals 103 a and 103 b denote coils that convert a drive signal into magnetic flux and apply the magnetic flux to the rotor 101 via the stator 102.
The stator 102 is provided with three saturable narrow portions 1022a, 1022b, and 1022c around the rotor hole 1020, and three magnetic poles 1021a, 1021b, and 1021c are formed. Saturable narrow portions 1021a, 1021b, and 1022c are provided with a narrow portion in a part of the magnetic path. For this reason, since the magnetic flux is most easily saturated in the stator 102, the magnetic flux is saturated only by the magnetic flux generated from the coils 103a and 103b.

Φ3a indicates a magnetic flux passing through the coil 103a, and the magnetic pole 1021a in the arrow direction of the magnetic flux Φ3a is a positive magnetic pole. The magnetic pole passing through the stator 1024 located between the coils 103a and 103b is the positive magnetic pole when the side is the S pole, and the magnetic pole 1021c side opposite to the arrow direction of the magnetic flux Φ3c shown in FIG. Use magnetic poles.

  Further, the magnetic flux Φ3d and the magnetic flux Φ3e are magnetic fluxes that close around the rotor hole 1020. The three saturable narrow portions 1022a, 1022b, and 1022c of the rotor hole 1020 are magnetically saturated with respect to the magnetism generated in the coils 103a and 103b by the drive pulse, but in the magnetism due to the free vibration of the rotor 101 after the drive. As a result, the magnetic flux Φ3d and the magnetic flux Φ3e that are closed around the rotor hole 1020 are generated. Thereby, Φ3a and Φ3b are weakened.

  The stator 102 has notches 1023a and 1023b formed around the rotor hole 1020, and a position where the rotation angle w of the rotor 101 is about 45 [deg] is a stable position when not operating (hereinafter referred to as a static stable position). Become.

  Since the rotor 101 rotates 180 [deg] in one step, the initial state of the rotor 101 is the state shown in FIG. 1a and the polarity of the rotor 101 is opposite to that in FIG. 1a (N pole is S pole and S pole is N pole). Two states are obtained.

  Further, in the first embodiment, the direction in which the rotor 101 rotates in the D1 direction is defined as forward rotation, and when the rotor 101 rotates in the D2 direction is defined as reverse rotation, and the rotation direction frequently used with respect to the rotation angle w = 0 deg (in the first embodiment, It is desirable to set the static stable position within 0 to 90 [deg] in the D1 direction.

  The coil 103a has coil terminals OUT1 and OUT2. The coil terminal OUT2 has a VDD potential that is a ground potential, and the coil terminal OUT1 has a VSS potential that is a potential lower than the VDD potential. An S pole is generated in the magnetic pole 1021c, and a magnetic flux acts on the rotor 101.

The coil 103b has coil terminals OUT3 and OUT4. When a current is passed with the coil terminal OUT4 as the VDD potential and the coil terminal OUT3 as the VSS potential, an N pole is generated in the magnetic pole 1021b and an S pole is generated in the magnetic pole 1021c. The magnetic flux is applied to the rotor 101. In both coils, if a current is passed in the opposite direction, the magnetic pole appearing on the magnetic pole is reversed.

FIG. 2A is a diagram showing a change in the amount of magnetic flux with respect to the rotor position in the first embodiment.
As shown in FIG. 2a, the magnetic flux Φ3a is the largest magnetic flux having the largest magnetic flux amount when the rotor 101 is at the rotational angle w = 225 deg, the smallest magnetic flux having the smallest magnetic flux amount at the rotational angle w = 45 deg, and the magnetic flux Φ3b is The maximum magnetic flux is obtained when the rotor 101 has a rotation angle w = 135 deg, the minimum magnetic flux is obtained when the rotation angle w = 315 deg. The magnetic flux Φ3c becomes the maximum magnetic flux when the rotor 101 has a rotation angle w = 180 deg, and the rotation angle w = 0 deg. At the minimum magnetic flux.

  FIG. 2 (b) is a diagram showing a change in counter electromotive current with respect to the rotor position in the first embodiment. Assuming that the rotor is rotating at a constant speed, each magnetic flux amount change in FIG. 2 (a) is differentiated. The back electromotive force change with respect to the rotor position is calculated.

  As shown in FIG. 2 (b), the counter electromotive current I3a is a counter electromotive current generated in the coil 103a. When the rotor 101 has a rotation angle w = 315 deg, the maximum counter electromotive current becomes the largest. The minimum counter electromotive current with the smallest counter electromotive current is obtained when the angle w = 135 deg, the counter electromotive current I3b is the counter electromotive current generated in the coil 103b, and the maximum counter current when the rotor 101 has a rotation angle w = 225 deg. The minimum counter electromotive current is obtained when the rotation angle w = 45 deg. The counter electromotive current I3c is a virtual counter electromotive current calculated by differentiating the magnetic flux Φ3c, and the maximum counter electromotive current is obtained when the rotor 101 has the rotation angle w = 270 deg. It becomes an electromotive current, and becomes the minimum counter electromotive current when the rotation angle w = 90 deg.

The magnetic flux Φ3c is a counter electromotive current when the coil terminal OUT1 and the coil terminal OUT3, the coil terminal OUT2 and the coil terminal OUT4 are connected, and the coils 103a and 103b are connected in parallel, and is a counter electromotive current obtained by adding the magnetic fluxes Φ3a and Φ3b. .
Therefore, the maximum counter electromotive current of the counter electromotive current I3c is larger than the maximum counter electromotive current of the counter electromotive currents I3a and I3b, and the minimum counter electromotive current of the counter electromotive current I3c is larger than the minimum counter electromotive current of the counter electromotive currents I3a and I3b. small.

  As described above, the magnetic flux Φ3a flowing through the coil 103a and the magnetic flux Φ3b flowing through the coil 103b are different in the rotation angle w that is the maximum magnetic flux and the minimum magnetic flux, and therefore, the back electromotive current generated when the rotor 101 is rotated by the drive signal. The output timing is also different. When the rotor rotation direction is switched, the polarity of the back electromotive force is switched, and when the rotor rotation direction is switched, and when the rotor stops and the speed becomes zero, the rotor rotation angle Regardless of w, the back electromotive force is zero.

Next, changes in the back electromotive force generated in the coils 103a and 103b when a drive signal is applied to the coils 103a and 103b and the rotor 101 rotates will be described.
In this description, from the state of the rotor 101 shown in FIG. 1a, a drive signal is applied to the coils 103a and 103b (OUT1 and OUT3 are VSS potential, OUT2 and OUT4 are VDD potential), and the rotor 101 rotates in the D1 direction. Give an explanation.

FIG. 2C is a diagram showing a change in counter electromotive current during rotation in the first embodiment, and FIG. 2D is a diagram showing a change in counter electromotive current during non-rotation in the first embodiment.
Reference numeral 220 denotes a drive signal applied to the coils 103 a and 103 b, 221 denotes a current generated in the coils 103 a and 103 b by the drive signal 220, and 223 denotes a rotation angle w of the rotor 101.

In the step motor of the present invention, the rotation of the rotor 101 is detected by observing a counter electromotive current before and after the rotor 101 rotates 180 degrees, and determines whether the rotor 101 is rotating or not rotating.
Therefore, the current waveform before and after the broken line A indicating the rotation angle w = 225 deg obtained by rotating the rotor 101 by 180 deg from the rotation angle w = 45 deg is confirmed.

  When the rotation of the rotor 101 in FIG. 2C is performed normally, the rotor 101 is rotated in the direction D1 from the rotation angle w = 45 deg to the region B by the drive signal as indicated by the rotation angle w223 in FIG. Then, from the vicinity of the elapsed time of 11 mS when the inertial force of the drive signal disappears, the motor slowly rotates in the direction D2 to the rotation angle w = 225 deg which is a static stable position, and stops at the rotation angle w = 225 deg.

  The output direction of the back electromotive currents I3a, I3b, and I3c when the rotation angle w in FIG. 2B is around 225 deg is a positive direction, but in the region B of FIG. 2C, the rotor 101 slowly moves in the D2 direction. Since it is rotating, the electromotive currents I3a and I3b are slightly generated in the negative direction, and I3c is generated in the negative direction with a larger amplitude.

  Further, when the rotation of the rotor 101 in FIG. 2D is not normally performed, the rotor 101 is rotated from the rotation angle w = 45 deg to the rotation angle w = 130 deg according to the drive signal as indicated by the rotation angle w223 in FIG. However, since the mechanical load is large, the inertial force of the drive signal disappears in the vicinity of the elapsed time of 4 mS, and slowly rotates in the D2 direction to the rotation angle w = 45 deg which is a static stable position. Stop at w = 45 deg.

  The output direction of the counter electromotive currents I3a, I3b, and I3c when the rotation angle w in FIG. 2B is 45 to 135 deg is a negative direction, but the rotor 101 slowly rotates in the D2 direction in the region B of FIG. Therefore, back electromotive currents I3a, I3b, and I3c are generated in the positive direction. Therefore, the determination of rotation / non-rotation can be made based on the difference in the polarity of the counter electromotive current in the region B in FIGS. 2C and 2D, but the counter electromotive current in the region B in FIG. Since the amplitudes of I3a and I3b are small, there is a possibility of erroneous detection due to the influence of noise or the like.

  For this reason, in the first embodiment of the present invention, the coils 103a and 103b are connected in parallel, the rotation of the rotor 101 is detected using the back electromotive current I3c having a large amplitude obtained by adding the back electromotive currents I3a and I3b, and the stable rotor The rotation detection method 101 is realized.

[Description of Overall Configuration of First Embodiment: FIG. 3]
Next, drive control of the two-coil step motor of Embodiment 1 will be described.
FIG. 3 is a block diagram of the drive control mechanism of the two-coil step motor according to the first embodiment. 1 is an electronic timepiece, 100 is a two-coil step motor (hereinafter referred to as a motor unit), 200 is a circuit unit that generates a drive signal for driving the motor unit 100, and detects the operating state of the motor unit 100, A control unit 300 controls the circuit unit 200.
The control unit 300 includes a pulse generation circuit 301 that generates a drive signal for driving the motor,
A rotation detection signal generation circuit 302 for generating a rotation detection signal of the motor;
The pulse generation circuit 301 includes a pulse selection circuit 303 that selects a pulse from the rotation detection signal generation circuit 302, and a control circuit 304 that controls the entire control unit 300.
The circuit unit 200 includes a driver circuit 201 that outputs a drive signal to the motor unit 100 according to a signal supplied from the pulse selection circuit 303;
A rotation detection circuit 202 that detects a counter electromotive current generated from the motor unit 100 and capable of grasping the rotation state of the motor unit 100;
The rotation detection circuit 202 includes a first detection signal generation circuit 2021 that detects a counter electromotive current in a first interval, a second detection signal generation circuit 2022 that detects a counter electromotive current in a second interval following the first detection interval, and , Is composed of.

The motor unit 100 generates magnetic flux to be applied to the rotor 101 by drive signals output from the rotor 101 and the driver circuit 201, and uses two coils 103a and 103b that convert changes in the magnetic flux generated in the rotor 101 into counter electromotive currents. Become.

Next, the configuration of the circuit unit 200 will be described with reference to the circuit diagram of FIG.
The circuit unit 200 includes a driver circuit 201 and a rotation detection circuit 202. The driver circuit 201 includes switches P1 and P2 for supplying a VDD potential as a drive signal to the coil 103a, and a switch N1 for supplying a VSS potential. N2 and the coil 103a and the coil 103b are connected in parallel.

  The rotation detection circuit 202 includes a first detection determination circuit 2021 and a second detection determination circuit 2022. The first detection determination circuit 2021 includes a high resistance R1 and a switch SP1, and the second detection determination circuit 2022 includes a high detection determination circuit 2022. It comprises a resistor R2 and a switch SP2.

Next, the driving cycle of the first embodiment will be described with reference to the pulse configuration diagram of FIG.
The driving cycle includes a normal hand movement pulse period 401 for driving the rotor 101, a rotation detection section 402 for detecting the rotation state of the rotor 101, and a drive signal stronger than the normal hand movement pulse period 401 when the rotor 101 is detected to be non-rotating. A correction pulse period 403 for outputting a correction pulse, and a pause period 404 during which no drive signal is supplied to the rotor 101 or rotation detection is not performed. The rotation detection section 402 is composed of two sections, a first section 4021 and a second section 4022. Further, when it is determined that the rotor 101 has rotated in the rotation detection section 402, the correction pulse is not output in the correction pulse period 403, and control is performed so as to maintain the state of the pause period 404.

  The first section 4021 is applied with a drive signal so that the area C in FIGS. 2C and 2D coincides with the second section 4022 and the area B in FIGS. 2C and 2D. The timing of the 1st area 4021 and the 2nd area 4022 is set from the elapsed time after.

Next, the switch states shown in FIG. 4 relating to switching of drive signals to each coil and rotation detection in the first embodiment will be described with reference to FIG.
The switch states shown in FIG. 4 occur in the forward rotation pause state of FIG. 6A that occurs in the pause period 404 during forward rotation, the normal hand movement pulse period 401 in the forward drive, and the correction pulse period 403 in FIG. (B) Forward rotation drive state 1, FIG. 6 (c) Forward rotation drive state 2, FIG. 6 (d) rotation detection state 1 occurring in the forward rotation drive rotation detection period 402, FIG. 6 (e). There are five states of rotation detection state 2.

  Next, the operation states of the switches SP1, SP2, P1, P2, N1, and N2 during forward rotation driving will be described with reference to FIG.

In the normal rotation pause state of FIG. 6A, since no magnetic flux is generated in the coils 103a and 103b, the potentials of OUT1, OUT2, OUT3, and OUT4 are made the same. Therefore, as shown in FIG. P2 is turned on, the switches N1 and N2 are turned off, and the potentials of the coil terminals OUT1, OUT2, OUT3, and OUT4 are set to the VDD potential.
Further, since the switches SP1 and SP2 are not in the rotation detection period, they are turned off.

When forward driving is performed when the N pole of the rotor 101 is at the magnetic pole 1021a as shown in FIG. 1, the polarity of the magnetic poles 1021a and 1021b is set to the N pole and the magnetic pole 1021c is set to the S pole. (Referred to as D1 direction).
For this reason, in order to set the potential of the coil terminals OUT1 and OUT3 to the VSS potential and the potential of the coil terminals OUT2 and OUT4 to the VDD potential, as shown in FIG. 6B, the switches N1 and P2 are turned on, and the switches N2 and P1 are turned off. And

Further, since the switches SP1 and SP2 are not in the rotation detection period, they are turned off.
Further, when forward rotation driving is performed when the S pole of the rotor 101 is at the magnetic pole 1021a, the rotor 101 is rotated in the D1 direction by setting the polarities of the magnetic poles 1021a and 1021b to the S pole and the magnetic pole 1021c to the N pole.

For this reason, in order to set the potential of the coil terminals OUT1 and OUT3 to the VDD potential and the potential of the coil terminals OUT2 and OUT4 to the VSS potential, the switches N1 and P2 are turned off and the switches N2 and P1 are turned on as shown in FIG. And
Further, since the switches SP1 and SP2 are not in the rotation detection period, they are turned off.

Next, the case where the rotation of the rotor 101 is detected will be described.
Even when the output of the drive signal is completed, the rotor 101 continues to move due to the inertial force, so that a counter electromotive current is generated in the coils 103a and 103b.
Since the back electromotive force generated from the rotor 101 changes in electrical polarity depending on the rotation direction of the rotor 101 and the direction of the magnetic poles, the state of the driver circuit 201 and the rotation detection circuit 202 is the normal rotation pause state of FIG. The forward rotation detection state 1 in FIG. 6D or the forward rotation pause state in FIG. 6A and the forward rotation detection state 2 in FIG. The generated back electromotive force is detected.

  The counter electromotive current generated in the output SO1 or SO2 of the circuit unit 200 is converted into a voltage (hereinafter referred to as a counter electromotive voltage) by the high resistances R1 and R2, and the control unit 300 determines that the counter electromotive voltage is greater than a predetermined threshold voltage V1. Count the number of times it has exceeded the VSS side.

  In the first embodiment, the number of times that the back electromotive voltage exceeds the threshold voltage V1 on the VSS side in 4021 in the first section is counted three times, and in the second section 4022, the back electromotive voltage is on the VSS side from the threshold voltage V1. The counter frequency is counted five times, and the counter electromotive voltage exceeds the threshold voltage V1 to the VSS side at 4021 in the first interval two times or more, and the counter electromotive voltage is the threshold voltage at 4022 in the second interval. When the number of times exceeding V1 to the VSS side is counted one or more times, it is determined that “the rotor 101 has rotated normally”, and in other cases, it is determined that “the rotor 101 has not rotated normally” I decided to. The setting of the number of times exceeding the threshold voltage V1 set here is an example, and is appropriately determined according to the characteristics of the step motor.

  The rotation detection state 1 in FIG. 6D is used when the output of the counter electromotive current is assumed to be the VDD potential and the OUT2 and OUT4 sides are the VSS potential when viewed from the high resistance R1, and the output SO2 of the circuit unit 200 is used. In order to compare the back electromotive voltages, as shown in FIG. 6D, the switches P1 and SP1 are turned on, the switches N1, N2, P2 and SP2 are turned off, and the voltage generated in the resistor R1 is compared with the threshold voltage V1. Thus, the rotation state of the rotor 101 is determined.

Further, in the rotation detection state 2 of FIG. 6E, when the back electromotive current output is assumed to be the high resistance R2, the back electromotive current output is assumed to be the VSS potential for OUT1, OUT3, and the VDD potential for the OUT2, OUT4 side. In order to compare the back electromotive force from the output SO1 of the circuit unit 200, the switches P2 and SP2 are turned on and the switches N1, N2, P1 and SP1 are turned off as shown in FIG. The rotation state of the rotor 101 is determined by comparing the voltage and the threshold voltage V1.
As described above, in the first embodiment, when the rotation of the rotor 101 is detected, the coil terminal OUT2 and the coil terminal OUT4 and the coil terminal OUT1 and the coil terminal OUT3 are connected to each other, so that the two coils 103a and 103b are connected in parallel. It is connected to the.

  For this reason, in the rotation detection after the rotation angle of the rotor 101 shown in FIG. 2C exceeds 225 deg, it is possible to determine the rotation detection with more back electromotive current, and thus accurate rotation detection is possible. It becomes.

[Description of Operation of First Embodiment]
Next, the operation of the first embodiment will be described with reference to FIG. 5, FIG. 6, FIG. 7, and FIG.
FIG. 7 is a diagram showing a motor state transition diagram for explaining a step operation when the rotor 101 is driven. FIG. 7A shows a motor state transition diagram when the normal rotation drive is normally performed. 7 (b) shows a motor state transition diagram when normal rotation driving is not performed normally.

  FIG. 8 shows that the outputs SO1 and SO2 of the circuit unit 200 are generated in the outputs SO1 and SO2 of the circuit unit 200 by the counter electromotive current and the counter electromotive current generated in the coils 103a and 103b by the rotor 101 driven by the drive signal waveform and inertia force. FIG. 8 (a-1) and FIG. 8 (a-2) show the case where the rotation is successful during normal rotation driving, and FIG. ), FIG. 8B-2 shows a case where rotation fails during forward rotation driving.

8A-1 and 8B-1, SO1 and SO2 indicate voltages generated at the outputs SO1 and SO2 of the circuit unit 200, and SO1 ′ and SO2 ′ indicate back electromotive currents of the coils 103a and 103b. Indicates the back electromotive voltage generated at the outputs SO1 and SO2 of the circuit unit 200,
8A-2 and FIG. 8B-2, a change in current flowing through the output SO2 of the circuit unit 200 is indicated.

  The static stable position of the rotor 101 in the rest period 404 is determined by the notches 1023a and 1023b. The static stable position of the rotor 101 is 225 [deg] in which the phase angle w is 45 [deg] and the N pole and the S pole are switched. ] Exists.

  In the description of the first embodiment, the phase angle w is 45 [deg] when the normal rotation operation is normally performed, and the phase angle w is 225 [deg] when the normal rotation operation is not normally performed. ] Will be described.

  In the first embodiment, the state of the driver circuit 201 and the rotation detection circuit 202 before performing the normal rotation operation is the normal rotation pause state of FIG. 6A, and the outputs SO1 and SO2 of the circuit unit 200 are at the VDD potential.

Further, the phase angle w of the rotor 101 is 45 [deg] as described above, and the state shown in FIG.
Next, the case where the forward rotation drive is performed from the above-described rest state 404 and the rotor 101 rotates normally will be described.

  As shown in FIG. 5, the state of the driver circuit 201 and the rotation detection circuit 202 becomes the normal rotation state 1 in FIG. The output SO1 of the circuit unit 200 is VSS and SO2 is the VDD potential, and the outputs SO1 and SO2 of the circuit unit 200 are as in the normal hand movement pulse period 401 in FIG.

Since the coils 103a and 103b generate magnetic flux in the same direction in the forward rotation state 1, magnetic flux is generated as in STEP2 of FIG. 7A, and the N pole is generated in the magnetic poles 1021a and 1021b, and the S pole is generated in the magnetic pole 1021c. Then, the rotor 101 rotates in the direction D1, and ST in FIG.
It becomes the state of EP3.

  After a predetermined time has elapsed, the driving cycle shifts from the normal hand movement pulse period 401 to the first section 4021 of the rotation detection period 402.

  When the driving cycle is the first section 4021, the states of the driver circuit 201 and the rotation detection circuit 202 are intermittent between the normal rotation pause state of FIG. 6A and the normal rotation detection state 1 of FIG. Repeat three times.

The rotor 101 maintains the rotation in the D1 direction by the inertial force, the rotor 101 rotates from the state of STEP 3 to STEP 4 in FIG. 7A, and the magnetic flux of the rotor 101 applied to the magnetic poles 1021a and 1021b changes from the S pole to the N pole. Therefore, a back electromotive force is generated in the coils 103a and 103b as in the first section 4021 of the driving cycle in FIG.
Since the driver circuit 201 and the rotation detection circuit 202 are in the normal rotation detection state 1, the output SO1 of the circuit unit 200 is at the VDD potential, and the output SO2 is connected to the VDD potential via the resistor R1. A counter electromotive current flows through R1, and a counter electromotive voltage is generated at the output SO2 of the circuit unit 200 as in the first section 4021 of the driving cycle in FIG.

The control unit 300 counts the number of times that the back electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the predetermined threshold voltage V1 toward the VSS side, and in the first embodiment, the first interval in FIG. In 4021, the number of times that the back electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the threshold voltage V1 to the VSS side is three. In addition, the drive cycle shifts from the first section 4021 to the second section 4022 when a predetermined time has elapsed. A configuration may be adopted in which a transition to the second section 4022 is made immediately when the threshold voltage V1 is exceeded twice.
When the driving cycle is the second section 4022, the states of the driver circuit 201 and the rotation detection circuit 202 are intermittent between the normal rotation pause state of FIG. 6A and the normal rotation detection state 2 of FIG. Repeat 5 times.

  The rotor 101 enters the transition state from STEP 4 to STEP 5 in FIG. 7A, the rotation direction of the rotor 101 changes from D1 to D2, and the magnetic flux of the rotor 101 applied to the magnetic poles 1021a and 1021b changes from N pole to S pole. Therefore, as in the second section 4022 in FIG. 8A-2, a counter electromotive current opposite to that in the first section 402 is generated in the coils 103a and 103b.

Since the states of the driver circuit 201 and the rotation detection circuit 202 are the forward rotation detection state 2, the output SO2 of the circuit unit 200 becomes the VDD potential, and the output SO1 of the circuit unit 200 is connected to the VDD potential via the resistor R2. Therefore, a counter electromotive current flows through the resistor R2, and a counter electromotive voltage is generated at the output SO1 of the circuit section 200 as in the second section 4022 in FIG.
The control unit 300 counts the number of times that the back electromotive voltage generated at the output SO1 of the circuit unit 200 exceeds the predetermined threshold voltage V1 to the VSS side, and the circuit unit in the second section 4022 of FIG. The number of times that the counter electromotive voltage generated at the output SO1 of 200 exceeds the VSS side from the threshold voltage V1 is two.

  The second section 4022 ends when a predetermined time elapses, and the rotor 101 stops at the static stable position of the rotor 101 at the phase angle w of 225 [deg] as in the state of STEP 5 in FIG.

If the count of the first section 4021 is two times or more and the count of the second section 4022 is one or more times, the control unit 300 determines that “the rotor 101 has rotated normally”, and the driving cycle is the correction pulse period 403, In the state of the rest period 404, the state of the rotation detection circuit 202 is set to the forward rotation rest state of FIG. 6A, and the outputs SO1 and SO2 of the circuit unit 200 are set to the VDD potential.
Next, a case where the rotor 101 does not rotate normally due to an impact or load fluctuation will be described.

  Note that the phase angle w of the rotor 101 at the start of driving is 225 [deg], the rotor 101 is in the state of STEP 1 in FIG. 7B, and the state of the rotation detection circuit 202 is the forward rotation pause in FIG. State.

  As shown in FIG. 5, the state of the driver circuit 201 and the rotation detection circuit 202 is the normal rotation state 2 in FIG. Thus, the output SO1 of the circuit unit 200 becomes the VDD potential, the SO2 becomes the VSS potential, and the outputs SO1 and SO2 of the circuit unit 200 become like the normal hand movement pulse period 401 in FIG.

  In the forward rotation state 1, the coils 103a and 103b generate magnetic flux in the same direction, so that magnetic flux is generated as shown in STEP 2 in FIG. 7B, and the S pole is generated in the magnetic poles 1021a and 1021b and the N pole is generated in the magnetic pole 1021c. However, the rotor 101 rotates in the direction D1, but since the driving force is insufficient, the rotor 101 slowly rotates to a position where the phase angle w is 315 [deg] or less as shown in STEP 3 of FIG. 7B.

  After a predetermined time has elapsed, the driving cycle shifts from the normal hand movement pulse period 401 to the first section 4021 of the rotation detection period 402.

  In the case where the driving cycle is the first section 4021, the states of the driver circuit 201 and the rotation detection circuit 202 are intermittently 3 between the normal rotation pause state of FIG. 6A and the normal rotation detection state 2 of FIG. Repeat once.

  When the phase angle w of the rotor 101 exists below 315 [deg] and no magnetic flux is generated from the coils 103a and 103b, the rotor 101 rotates to the nearest static stable position at the phase angle w of 225 [deg]. Therefore, the rotation direction changes from the D1 direction to the D2 direction, and the state of FIG. 7 (b) STEP3 starts to shift to the state of FIG. 7 (b) STEP4, and the magnetic flux of the rotor 101 applied to the magnetic poles 1021a and 1021b changes from the N pole Since it changes to the pole, back electromotive currents of the coils 103a and 103b are generated as in the first section 4021 in FIG. 8B-2.

Since the driver circuit 201 and the rotation detection circuit 202 are in the normal rotation detection state 2, the output SO2 of the circuit unit 200 becomes the VDD potential, and the output SO1 of the circuit unit 200 is connected to the VDD potential via the resistor R2. Therefore, a counter electromotive current flows through the resistor R2, and a counter electromotive voltage is generated at the output SO1 of the circuit unit 200 as in the first section 4021 in FIG. 8B-1.
The control unit 300 counts the number of times that the back electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the predetermined threshold voltage V1 to the VSS side, and in the first embodiment, the first interval in FIG. In 4021, the number of times that the back electromotive voltage generated at the output SO1 of the circuit unit 200 exceeds the threshold voltage V1 to the VSS side is three.
Further, the driving cycle shifts from the first section 4021 to the second section 4022 when a predetermined time has elapsed.

  When the driving cycle is the second section 4022, the states of the driver circuit 201 and the rotation detection circuit 202 are intermittent between the normal rotation pause state of FIG. 6A and the normal rotation detection state 1 of FIG. Repeat 5 times.

Since the rotor 101 is moving from STEP 3 to STEP 4 in FIG. 7B as in the first section 4021, the driving cycle in FIG. 8B-1 is the coil 103 a, as in the second section 4022. 103 b generates a counter electromotive current in the same direction as the first section 4021.
Since the driver circuit 201 and the rotation detection circuit 202 are in the normal rotation detection state 1, the output SO1 of the circuit unit 200 becomes the VDD potential, and the output SO2 of the circuit unit 200 is connected to the VDD potential via the resistor R1. Therefore, a counter electromotive current flows through the resistor R1, but since the electrical polarity is opposite, no counter electromotive voltage is generated at the output SO2 of the circuit section 200 as shown in FIG. 8B-1.

The control unit 300 counts the number of times that the back electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the predetermined threshold voltage V1 to the VSS side, but no back electromotive voltage is generated at the output SO2 of the circuit unit 200. Therefore, the count in the second section 4022 is zero.
The second section 4022 shifts to the correction pulse period 403 when a predetermined time has elapsed. The controller 300 determines that the “rotor 101 has rotated normally” if the count of the first section 4021 is two times or more and the count of the second section 4022 is one or more times. Since the count of the section 4022 is 0, it is determined that “the rotor 101 is not rotating normally”.

  In the rotation detection period 402, when it is determined that the rotation detection result is “the rotor 101 does not rotate normally”, the state of the driver circuit 201 and the rotation detection circuit 202 in the correction pulse period 403 is positive in FIG. In the inversion state 2, the output SO2 of the circuit unit 200 is at the VSS potential and SO1 is at the VDD potential, and the outputs SO1 and SO2 of the circuit unit 200 are as in the correction pulse period 403 in FIG.

Therefore, since the coils 103a and 103b generate magnetic flux in the same direction in the forward rotation state 2, magnetic flux is generated as shown in STEP 5 in FIG. 7B, and the S pole is generated in the magnetic poles 1021a and 1021b and the N pole is generated in the magnetic pole 1021c. And the rotor 101 rotates in the direction D1.
Since the correction pulse period 403 is longer than the normal hand movement pulse period 401, the magnetic flux energy applied to the rotor 101 during the correction pulse period 403 is larger than the magnetic flux energy applied to the rotor 101 during the normal hand movement pulse period 401. As shown in FIG. 7 (b) STEP3, the phase angle w is rotated beyond the position of 315 [deg], and the state shown in FIG. 7 (b) STEP6 is obtained.

  Further, when the predetermined time has elapsed, the driving cycle shifts from the correction pulse period 403 to the rest period 404, and the rotor 101 is in the stable stable position of the rotor 101 in the state of STEP 6 in FIG. deg], the driver circuit 201 and the rotation detection circuit 202 are in the normal rotation pause state of FIG. 6A, and the outputs SO1 and SO2 of the circuit unit 200 are at the VDD potential.

  As described above, when the rotation of the rotor 101 is detected as in the first embodiment, the detection is performed by synthesizing the counter electromotive currents generated in the coils 103a and 103b by connecting the coils 103a and 103b in parallel. Therefore, the rotation can be detected with a large amount of back electromotive current at the time of rotation detection, so that stable rotation detection of the rotor 101 can be realized.

[Description of Modification 1]
Next, Modification 1 of Embodiment 1 of the present invention will be described with reference to FIG.
Moreover, the same code | symbol is attached | subjected to the same structure and the description is abbreviate | omitted.

FIG. 9 is a circuit diagram for explaining the circuit unit 201 of the first modification. In the circuit configuration of FIG. 4, the switch TG2 for controlling connection / disconnection of the coil terminals OUT1 and OUT3, and the connection of the coil terminals OUT2 and OUT4. In addition, switches P3, P4, N3, and N4 that apply drive signals to switches TG1, OUT3, and OUT4 that control disconnection are added.
In the first embodiment, since the coils 103a and 103b are connected in parallel, the coil 103a
103b can always output only in the same direction, but in the first modification, the switches TG1 and TG2 can be turned off to perform different drive control on the coils 103a and 103b. The degree of freedom increases.

Further, in the rotation detection section 402 as in the first embodiment, the switches TG1 and TG2 are turned on and only when the rotation of the rotor 101 is detected, the coils 103a and 103b are connected in parallel to detect the rotation as in the first embodiment. It is also possible.
The difference between the operation in the first modification and the first embodiment is only the operation of the switches TG1, TG2, P3, P4, N3, and N4.
When the same operation as in the first embodiment is performed, the switch P3 is operated in synchronization with the switch P1, the switch P4 is operated in the switch P2, the switch N3 is operated in the switch N1, the switch N4 is operated in synchronization with the switch N2, and the TG1 and TG2 are turned on. Since the same operation as that of the first embodiment is performed, the description of the operation is omitted.

Further, in the first embodiment, the rotor 101 can perform only the forward rotation operation, but in the first modification, the reverse rotation operation is also possible.
The switch state when the following rotor 101 is operated in reverse will be described.

  As shown in FIG. 1, when the rotor 101 is driven reversely when the rotation angle is w = 45 deg, the stator magnetic pole 1021a has an N pole, the stator magnetic pole 1021b has an S pole, and the stator magnetic pole 1021c has an opposite magnetic pole between the drive coils 103a and 103b. Therefore, the magnetic polarity is not generated.

Therefore, in order to set the potential of the coil terminals OUT1 and OUT4 to the VDD potential and the potential of the coil terminals OUT2 and OUT3 to the VSS potential, the switches P1, N2, N3, and P4 are turned on, and the switches N1, P2, P3, and N4 are turned off. To do.
Further, the switches SP1, SP2, TG1, and TG2 are OFF because they are not in the rotation detection period.

  Further, when the rotor 101 is driven in reverse when the rotation angle is w = 225 deg, the stator magnetic pole 1021a is affected by the S pole, the stator magnetic pole 11021b is the N pole, and the stator magnetic pole 1021c is affected by the opposite magnetic poles of the drive coils 103a and 103b. Therefore, the magnetic polarity is not generated.

Therefore, in order to set the potentials of the coil terminals OUT1 and OUT4 to the VSS potential and the coil terminals OUT2 and OUT3 to the VDD potential, the switches P1, N3, N2, and P4 are turned off, and the switches N1, P3, P2, and N4 are turned on. To do.
Further, the switches SP1, SP2, TG1, and TG2 are OFF because they are not in the rotation detection period.
As described above, in the first modification, in addition to the rotation detection operation of the first embodiment, the rotation operation of the rotor 101 can be rotated forward and backward.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described.
In the first embodiment, the rotation angle w of the rotor 101 is determined based on the counter electromotive current I3c in the region B and the region C to determine whether the rotor 101 is rotated or not.
When the rotation angle w of the rotor 101 is in the region C, when the rotor 101 rotates or does not rotate, the counter electromotive force I3c is output in the positive direction in both cases, so the region C cannot be used effectively, and in effect. Since the determination is made only in the region B, there is a portion inferior in the reliability of the determination of the rotation or non-rotation of the rotor 101.

  FIG. 10 is a diagram showing a change in counter electromotive current when the parallel connection of the coils 103a and 103b is reversed from FIGS. 2 (c) and 2 (d). FIG. 10 (a) is a diagram of FIG. ) Is a diagram showing a change in counter electromotive current during non-rotation.

  I3d ′ is a counter electromotive current obtained by reversing the parallel connection of the coils 103a and 103b with the counter electromotive current I3c and subtracting the counter electromotive current I3b from the counter electromotive current I3a. Specifically, the coil terminal OUT1 and the coil terminal OUT4 The counter electromotive current when the coil terminal OUT2 and the coil terminal OUT3 are connected and the coils 103a and 103b are connected in parallel is shown.

  In the state where the rotor 101 is rotating normally, in the region C of FIG. 2C, the back electromotive force I3c when the coils 103a and 103b are connected in parallel is output in the negative direction, so that I3b is output in the negative direction. The back electromotive current was small,

The counter electromotive current I3d ′ in the region C in FIG. 10A is such that the coil 103a and the coil 103b are connected in reverse to FIG. 2C, so that the counter electromotive current of I3d ′ is larger than that of I3a. In the state where the rotor 101 did not rotate normally due to an increase in mechanical load, in the region C of FIG. 2C, the counter electromotive current I3c is normal because I3b is in the positive direction and the counter electromotive current I3a is almost zero. The counter electromotive current flows in the positive direction as in
The counter electromotive current I3d ′ in the region C of FIG. 10A is the counter electromotive current I3d ′ in the negative direction opposite to that of I3b because the coil 103a and the coil 103b are connected in the opposite direction of FIG. 2C. Flows.

In the state where the rotor 101 is rotating normally, in the region B of FIG. 2C, the back electromotive force I3c when the coils 103a and 103b are connected in parallel is output in the negative direction by I3b and I3a. , The back electromotive force was larger in the negative direction than I3a and I3b.
The counter electromotive current I3d ′ in the region B in FIG. 10A is close to 0 because I3b and I3a cancel each other.

In the state where the rotor 101 does not rotate normally due to an increase in the mechanical load, the counter electromotive current I3c in the region B of FIG. 2C is in the positive direction, so that the counter electromotive current I3c is greater than I3a and I3b. The current was increasing in the positive direction,

The counter electromotive current I3d ′ in the region B in FIG. 10A is close to 0 because I3b and I3a cancel each other.
In view of the above, in the second embodiment, in order to detect the rotation of the rotor 101 with higher accuracy, in the detection of the region C, the coil terminal OUT1 and the coil terminal OUT4, and the coil terminal OUT2 and the coil terminal OUT3 are connected and back electromotive. The rotation detection is determined by the current I3d ′,
In the detection of the region B, the coil terminal OUT1 and the coil terminal OUT3, the coil terminal OUT2 and the coil terminal OUT4 are connected, and the rotation detection is determined by the back electromotive current I3c.

[Description of Overall Configuration of Embodiment 2: FIG. 12]
Next, drive control of the two-coil step motor of the second embodiment will be described.
In the second embodiment, as shown in FIG. 12, the driver circuit 200 of the first embodiment includes
A switch TG1 provided between the coil terminal OUT2 and the coil terminal OUT4;
A switch TG2 provided between the coil terminal OUT1 and the coil terminal OUT3;
A switch TG3 provided between the coil terminal OUT1 and the coil terminal OUT4;
A switch TG4 provided between the coil terminal OUT2 and the coil terminal OUT3 is added.

  In addition, the same number is attached | subjected about the component similar to Embodiment 1, and description is abbreviate | omitted. Next, in the second embodiment, the switch states shown in FIG. 12 relating to switching of drive signals to each coil and rotation detection are the same as those in the first embodiment in which the switches TG1 and TG2 are turned on and the switches TG3 and TG4 are turned off. As shown in FIG. 13A, the switches TG1 and TG2 are in the OFF state and the switches TG3 and TG4 are in the ON state in the rolling pause state, the forward driving state 1, the forward driving state 2, the rotation detection state 1 and the rotation detection state 2. A rotation detection state 3 and a rotation detection state 4 shown in FIG.

Next, the rotation detection state 3 and the rotation detection state 4 will be described regarding the operation state of the switch in the second embodiment.
FIG. 13A is a diagram showing the switch state of the rotation detection state 3 in the second embodiment, and the output of the counter electromotive current is viewed from the high resistance R1, and the OUT1, OUT4 are VDD potential, and the OUT2, OUT3 side is VSS potential. In order to compare the back electromotive force from the output SO2 of the circuit unit 200, the switches P1, SP1, TG3, and TG4 are turned on and the switches N1, N2, and P2 are turned on as shown in FIG. SP2, TG1, and TG4 are turned OFF, and the rotation state of the rotor 101 is determined by comparing the voltage generated in the resistor R1 with the threshold voltage V1.

  FIG. 13B is a diagram illustrating a switch state of the rotation detection state 4 in the second embodiment, where the back electromotive current output is viewed from the high resistance R2, the back electromotive current output is OUT1, and OUT4 is the VSS potential. In order to compare the back electromotive force from the output SO1 of the circuit unit 200 when the OUT2 and OUT3 sides are assumed to be the VDD potential, the switches P2, SP2, TG3, and TG4 are turned on as shown in FIG. The switches N1, N2, P1, SP1, TG1, and TG4 are turned off, and the rotational state of the rotor 101 is determined by comparing the voltage generated in the resistor R2 with the threshold voltage V1.

[Description of Operation of Embodiment 2]
Next, the operation of the second embodiment will be described with reference to FIG. 5, FIG. 6, FIG. 7, and FIG.
FIG. 11 is a detection correlation diagram showing the correlation between the drive signal waveform and the counter electromotive current in the second embodiment. The step operation when the rotor 101 of the second embodiment is driven operates in the steps of the normal hand movement pulse period 401, the rotation detection period 402, the correction pulse period 403, and the rest period 404 of FIG. The operation differs from the first embodiment only in the rotation detection period 402.
For this reason, the description of the normal hand movement pulse period 401, the correction pulse period 403, and the pause period 404 will be omitted.

Note that the first section 4021 is the area C in FIGS. 10A and 10B, and the second section 4022 is after the drive signal is applied so as to match the area B in FIGS. 2C and 2D. The timing of the 1st area 4021 and the 2nd area 4022 is set from the elapsed time from.
The phase angle w of the rotor 101 is 45 [deg] as in the first embodiment, the switches TG1 and TG2 are turned on, the switches TG3 and TG4 are turned off, and the rotation detection circuit 202 in the normal hand movement pulse period 401. This state is carried out in the normal rotation state 1 in FIG.
In the second embodiment, as in the first embodiment, when the normal hand movement pulse period 401 ends, the driving cycle shifts from the normal hand movement pulse period 401 to the first section 4021 of the rotation detection period 402.

  In the case where the drive cycle is the first section 4021, the driver circuit 201 and the rotation detection circuit 202 are switched off by turning off the switches TG 1 and TG 2 and turned on by turning on the switches TG 3 and TG 4. The state of the forward rotation detection state 3 in FIG. 13A is intermittently repeated three times.

  The rotor 101 maintains the rotation in the D1 direction by the inertial force, the rotor 101 rotates from the state of STEP 3 to STEP 4 in FIG. 7A, and the magnetic flux of the rotor 101 applied to the magnetic poles 1021a and 1021b changes from the S pole to the N pole. Therefore, back electromotive force is generated in the coils 103a and 103b as in the first section 4021 in FIG.

  Since the driver circuit 201 and the rotation detection circuit 202 are in the forward rotation detection state 3, the output SO1 of the circuit unit 200 is at the VDD potential, and the output SO2 of the circuit unit 200 is connected to the VDD potential via the resistor R1. Therefore, a counter electromotive current flows through the resistor R1, and a counter electromotive voltage is generated at the output SO2 of the circuit unit 200 as in the first section 4021 in FIG.

The control unit 300 counts the number of times that the back electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the predetermined threshold voltage V1 to the VSS side, and in the second embodiment, the first interval in FIG. In 4021, the number of times that the back electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the threshold voltage V1 to the VSS side is three. Further, the driving cycle shifts from the first section 4021 to the second section 4022 when a predetermined time has elapsed. A configuration may be adopted in which the second section 4022 is immediately started when the threshold voltage V1 is exceeded twice.
When the driving cycle is the second section 4022, the states of the driver circuit 201 and the rotation detection circuit 202 are the switches TG1 and TG2 are turned on, the switches TG3 and TG4 are turned off, and the forward rotation rest state of FIG. The state of forward rotation detection state 4 of 6 (e) is repeated intermittently 5 times.

  The rotor 101 is in the transition state from STEP 4 to STEP 5 in FIG. 7A, the rotation direction of the rotor 101 changes from D1 to D2, and the direction of the magnetic flux generated from the rotor 101 applied to the magnetic poles 1021a and 1021b is switched. As in the second section 4022 in FIG. 11A-2, a counter electromotive current opposite to that in the first section 4021 is generated in the coils 103a and 103b.

  Since the driver circuit 201 and the rotation detection circuit 202 are in the normal rotation detection state 4, the output SO2 of the circuit unit 200 is the VDD potential, and the output SO1 of the circuit unit 200 is connected to the VDD potential via the resistor R2. Therefore, a counter electromotive current flows through the resistor R2, and a counter electromotive voltage is generated at the output SO1 of the circuit unit 200 as in the second section 4022 in FIG.

The control unit 300 counts the number of times that the back electromotive voltage generated at the output SO1 of the circuit unit 200 exceeds the predetermined threshold voltage V1 to the VSS side, and in the second section 4022 of FIG. The number of times that the back electromotive voltage generated at the output SO1 of the circuit unit 200 exceeds the threshold voltage V1 to the VSS side is two.
The second section 4022 ends when a predetermined time elapses, and the rotor 101 stops at the static stable position of the rotor 101 at the phase angle w of 225 [deg] as in the state of STEP 5 in FIG.

If the count of the first section 4021 is two times or more and the count of the second section 4022 is one or more times, the controller 300 determines that “the rotor 101 has rotated normally” and the drive cycle is the correction pulse period 403. In the rest period 404, the state of the rotation detection circuit 202 is set to the forward rotation rest state of FIG. 6A, and the outputs SO1 and SO2 of the circuit unit 200 are set to the VDD potential.
Next, a case where the rotor 101 does not rotate normally due to an impact or load fluctuation will be described.

Note that the phase angle w of the rotor 101 at the start of driving is 225 [deg], and the rotor 101 is in the state of STEP 1 in FIG. 7B. The switches TG1 and TG2 are turned on and the switches TG3 and TG4 are turned off. In the normal hand movement pulse period 401, the rotation detection circuit 202 is in the forward rotation state 2 of FIG. 6C, and the rotor 101 has a rotation angle w of 315 [deg] or less as shown in STEP 3 of FIG. 7B. Rotate slowly to position.
In the second embodiment, as in the first embodiment, when the normal hand movement pulse period 401 ends, the driving cycle shifts from the normal hand movement pulse period 401 to the first section 4021 of the rotation detection period 402.
When the drive cycle is the first section 4021, the driver circuit 201 and the rotation detection circuit 202 are intermittently switched between the normal rotation pause state of FIG. 6A and the normal rotation detection state 2 of FIG. Repeat three times.

When the phase angle w of the rotor 101 exists below 315 [deg] and no magnetic flux is generated from the coils 103a and 103b, the rotor 101 rotates to the nearest static stable position at the phase angle w of 225 [deg]. Therefore, the direction of rotation changes from the D1 direction to the D2 direction, and the transition from the state of STEP 3 in FIG. 7B to the state of STEP 4 starts, and the direction of the magnetic flux generated from the rotor 101 applied to the magnetic poles 1021a and 1021b is switched. As shown in (b-2), back electromotive currents of the coils 103a and 103b are generated.
Since the driver circuit 201 and the rotation detection circuit 202 are in the normal rotation detection state 4, the output SO2 of the circuit unit 200 is the VDD potential, and the output SO1 of the circuit unit 200 is connected to the VDD potential via the resistor R2. Therefore, a counter electromotive current flows through the resistor R2, but since the electrical polarity is opposite, no counter electromotive voltage is generated at the output SO1 of the circuit unit 200 as shown in FIG.

The control unit 300 counts the number of times that the back electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the predetermined threshold voltage V1 toward the VSS side, and in the second embodiment, the first interval in FIG. In 4021, the number of times that the counter electromotive voltage generated at the output SO1 of the circuit unit 200 exceeds the threshold voltage V1 to the VSS side is zero.
Further, the driving cycle shifts from the first section 4021 to the second section 4022 when a predetermined time has elapsed.

  In the case where the driving cycle is the second section 4022, the states of the driver circuit 201 and the rotation detection circuit 202 are the switches TG1 and TG2 turned on, the switches TG3 and TG4 are turned off, and the forward rotation rest state of FIG. The state of forward rotation detection state 1 of 6 (d) is repeated 5 times intermittently.

  Since the rotor 101 is moving from STEP 3 to STEP 4 in FIG. 7B as in the first section 4021, the coils 103 a and 103 b are connected to the first section 4021 and the coil 103 a and 103 b as shown in FIG. A counter electromotive current in the same direction is generated.

  Since the states of the driver circuit 201 and the rotation detection circuit 202 are the forward rotation detection state 1, the output SO1 of the circuit unit 200 becomes the VDD potential, and the output SO2 of the circuit unit 200 is connected to the VDD potential via the resistor R1. Therefore, a counter electromotive current flows through the resistor R1, but since the electrical polarity is opposite, no counter electromotive voltage is generated at the output SO2 of the circuit unit 200 as shown in FIG.

The control unit 300 counts the number of times that the counter electromotive voltage generated at the output SO2 of the circuit unit 200 exceeds the predetermined threshold voltage V1 to the VSS side, but the counter electromotive voltage is generated at the output SO2 of the circuit unit 200. Therefore, the count in the second section 4022 is zero.
The second section 4022 shifts to the correction pulse period 403 when a predetermined time has elapsed.

As described above, in the second embodiment, it is possible to determine whether the rotor 101 is rotating or not rotating in two rotation detection sections by changing the connection state of the coils 103a and 103b in the rotation detection period 401 and the rotation detection period 402. Therefore, rotation detection can be performed more accurately than in the first embodiment.

  In the second embodiment, the rotation and non-rotation determination of the rotor 101 is performed after the first section 4021 and the second section 4022 are implemented. However, if it can be determined that the rotor 101 does not rotate in the first section 4021, the rotation detection period 402. The rotor 101 may be rotated in the correction pulse period 403 without executing the above.

  Further, when the rotation is detected by switching the switches TG1, TG2, TG3, and TG4, switch noise is generated when the switches TG1, TG2, TG3, and TG4 are switched. Therefore, after the switches TG1, TG2, TG3, and TG4 are switched. The rotation may be detected after a certain time has elapsed.

[Description of effects]
As described above, when the rotation of the rotor 101 is detected in the two-coil step motor, the rotation of the rotor 101 can be reliably detected if the terminal outputs of the coils 103a and 103b are switched appropriately and connected in parallel. Therefore, it is possible to operate with a pulse of a marginal energy according to the load condition, so that the power consumption can be reduced.

DESCRIPTION OF SYMBOLS 100 Motor part 101 Rotor 1020 Rotor hole 1021a, 1021b, 1021c Magnetic pole 1022a, 1022b Slit part 1022c Magnetic flux saturation part 1023a, 1023b Notch part 103a Coil 103a
103b Coil 103b
DESCRIPTION OF SYMBOLS 200 Circuit part 201 Driver circuit 202 Rotation detection circuit 2021 1st detection circuit 2022 2nd detection circuit 300 Control part 301 Pulse generation circuit 302 Rotation detection signal generation circuit 303 Pulse selection circuit 304 Control circuit 401 Normal hand movement pulse period 402 Rotation detection area 4021 First section 4022 Second section 403 Correction pulse period

Claims (4)

A rotor composed of a two-pole magnetized permanent magnet;
A first coil and a second coil for supplying magnetic force for rotating the rotor;
A stator having a rotor hole for accommodating the rotor, and for inducing magnetic force generated from the first coil and the second coil to the rotor;
A stepping motor control device comprising:
Includes a circuit portion and a rotation detecting circuit and drivers circuit, and a control unit for controlling the circuit unit,
The control unit includes a control circuit that controls a pulse generation circuit and a rotation detection signal generation circuit that outputs a rotation detection signal for detecting an operation state of the rotor ,
The pulse generation circuit generates a correction pulse stronger than the normal movement pulse together with the normal movement pulse,
The rotation detection circuit outputs the rotation detection signal from the rotation detection signal generation circuit to the driver circuit after the normal hand movement pulse is applied to the first coil and the second coil. at the timing of the good Ri rotation detecting period, wherein the normal rotation detecting a state where the first coil and the second coil is connected to the rotation detecting circuit, the timing is not said rotation detection period, said by the driver circuit A normal rotation pause state in which the first coil and the second coil are not connected to the rotation detection circuit;
Wherein the rotation detection signal generating circuit, and outputs a rotation detection signal Ru was intermittently repeated the forward hibernation and the normal rotation detecting state to the driver circuit,
Wherein the control unit, the rotation output from the detection circuit performs detection of by Ri counter electromotive current to the free vibration of the rotor, determines the rotation and non-rotation by observing the front and rear of the counter current the rotor is rotated 180deg When the rotor is detected to be non-rotating, the correction pulse for rotating the rotor is output to the driver circuit. When the rotor is detected to be rotated, the correction pulse is output to the driver. Control not to output to the circuit, and connect the first coil and the second coil in parallel when detecting rotation,
The stepping motor control device is characterized in that the counter electromotive current is detected by using a counter electromotive current obtained by superimposing a counter electromotive current generated in the first coil and a counter electromotive current generated in the second coil. The stepping motor control device according to claim 1 , wherein the first coil and the second coil are directly connected to the common driver circuit. One terminal of the first coil and one terminal of the second coil are connected to a first switch;
The other terminal of the first coil and the other terminal of the second coil are connected to a second switch;
The control circuit is at least in a section during the rotation detection,
By closing the first switch and the second switch,
The stepping motor control device according to claim 1 , wherein the first coil and the second coil are connected in parallel. One terminal of the first coil and the other terminal of the second coil are connected to a third switch;
The other terminal of the first coil and one terminal of the second coil are connected to a fourth switch;
The rotation detection section has at least a first detection section and a second detection section,
In the first detection interval,
Close the first switch and the second switch;
By opening the third switch and the fourth switch,
Connecting the first coil and the second coil in parallel;
In the second detection interval,
Open the first switch and the second switch;
By closing the third switch and the fourth switch,
The stepping motor control device according to claim 3 , wherein the first coil and the second coil are connected in parallel.

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