JP5490461B2 - Stepping motor drive device - Google Patents

Description

The present invention relates to a stepping motor driving apparatus that microsteps a stepping motor.

  Stepping motors are widely used in various devices by taking advantage of characteristics such as easy positioning control and confirmation in an open loop without using a position sensor. As one of the methods for driving the stepping motor, there is a microstep driving method in which the driving current supplied to the motor winding is finely increased / decreased so that it can be driven in a minute angle unit compared to the basic step angle unique to the motor. As a conventional example of a microstep drive type drive device, there is one disclosed in Patent Document 1 or the like.

JP 2001-197783 A

  However, in the case of the above conventional example, it is possible to drive the stepping motor with high resolution. However, in reality, the uniformity of the angle division is not maintained, and it is difficult to achieve high accuracy. Has been. Further, the number of phase of the stepping motor to be used is generally determined by the reduction ratio of the mechanical system and the coordinate system to be controlled, and in this connection, it is relatively inexpensive compared to other motors. A two-phase or three-phase stepping motor may be used, and another problem is pointed out that it is difficult to reduce the cost.

  The present invention was created under the above-described background, and an object of the present invention is to provide a stepping motor driving device capable of achieving high accuracy and low cost of the device including the stepping motor. There is to do.

In order to solve the above-described problems, the stepping motor driving device of the present invention is a PWM current control type stepping motor driving device in which current data necessary for microstep driving of the stepping motor is sequentially obtained for each microstep angle. A pre-recorded memory unit, an address generation unit that sequentially reads out current data on the memory unit in accordance with an input pulse, and a PWM that generates a PWM signal having a duty ratio corresponding to the current data read from the memory unit A signal generator, a phase excitation counter that counts the number of steps in the excitation sequence according to the input pulse input, and a phase distribution pattern corresponding to the number of steps indicated by the phase excitation counter for phase-distributing the PWM signal and exciting each phase. A phase distribution circuit section for generating a signal, a plurality of switching elements, and each switch; A switching unit for generating each phase current of the stepping motor a quenching device turns on and off in response to the phase excitation signal, the switching element is in an active state, H-level when it is inactive, the current values of L level A current balance adjustment section that enables fine adjustment , and the memory section is finely adjusted in advance for each microstep angle so that a stepping motor that is actually used can rotate at an equal division angle.

According to the present invention described above, since the current data recorded in the memory unit is finely adjusted for each microstep angle, as a result, when the stepping motor is driven by a microstep, the uniformity of the angle division is maintained, Along with this, it becomes possible to increase the accuracy of driving the motor. In addition, since the current balance adjusting unit is provided, when the current values of the H level and the L level when the other switching elements are in the active state and the inactive state are finely adjusted in the ± direction, The current value of the switching element related to the control is also finely adjusted in the opposite direction. Therefore, even if there are variations in the characteristics of the output stage of the two-phase stepping motor or the driving device, it is possible to appropriately balance the current between the switching elements. Therefore, the advance angle of the motor can be made accurate, and as a result, it is possible to improve the precision of microstep drive.

  As for the phase distribution circuit unit of the above-mentioned device, in addition to the PWM signal generated by the PWM signal generation unit with the phase distribution pattern corresponding to the number of steps indicated by the phase excitation counter unit, an H level signal and an L level signal are output. It is preferable that the phase excitation signal is generated by phase distribution.

  According to the invention of the subordinate concept described above, since the switching elements related to the fine current control necessary for the micro step drive are not all phases but only a part, the configuration relating to the fine current control is simplified. Further, since the H level or L level signal is distributed to the other switching elements, there is another effect that high torque can be obtained in this respect.

  The above-described apparatus may have a configuration having a resolution setting unit for setting and inputting a resolution when the stepping motor is micro-step driven. In this case, as the address generation unit, it is preferable to use a configuration in which when reading current data sequentially from the memory unit, the read address is changed for each input pulse by the number C of jumps corresponding to the resolution.

  According to the above-described invention of the subordinate concept, it is possible to easily realize the uniformity of the angle division described above, and to obtain a merit in terms of cost.

  When the number of phases of the stepping motor (full step angle: x) is N (N ≧ 2), the resolution setting unit has an advance angle per step with the N phase stepping motor (full step angle: y). It is preferable that the resolution RM corresponding to the advance angle of the M (M ≠ N) phase stepping motors having the same can be set and inputted. The address generation unit is configured to change the read address for each input pulse input by the number of jumps C corresponding to the resolution RN obtained by multiplying the resolution RM by x / y when sequentially reading current data from the memory unit. To do.

  According to the invention of the subordinate concept described above, the lead angle of the M-phase stepping motor is realized while actually using the N-phase stepping motor. There is no need to select the number of phases of the motor according to the reduction ratio or the like. In addition, it is possible to use a relatively inexpensive two-phase and three-phase stepping motor for all controlled objects and the like, and a great merit is obtained in terms of cost.

  As the memory unit of the above-described device, it is preferable to use a memory unit in which the number W of current data is a multiple of M and is set to a value that can be divided by the number C of jumps corresponding to the resolution of the resolution setting unit. Preferably, the number W of current data is a common multiple of M and N, and an integer multiple of W is set to a value that can be divided by the number of jumps C corresponding to the resolution of the resolution setting unit. good.

  According to the invention of the subordinate concept described above, the resolution setting range can be increased without increasing the capacity of the memory unit, and a great merit can be obtained in terms of cost.

It is a block diagram of the stepping motor drive device concerning an embodiment of the invention. It is a figure for demonstrating the data content recorded on the memory part of the apparatus. It is a figure which shows the relationship between the resolution of a stepping motor, a lead angle, etc. for demonstrating operation | movement of the address setting part of the apparatus. It is a figure which shows the excitation sequence employ | adopted as the same apparatus. It is a figure which shows the waveform of the various excitation signals which turn on / off each switching element of the apparatus. It is explanatory drawing which shows the direction etc. of the electric current which flows into a switching motor for every step. It is the figure which showed typically the change of the electric current which flows into each phase coil of the stepping motor. It is a figure for demonstrating the stepping motor drive device which concerns on the modification of the apparatus, Comprising: It is a figure corresponding to FIG. It is a figure corresponding to FIG. 5 of the same apparatus.

  A stepping motor driving device (hereinafter simply referred to as a driving device) according to an embodiment of the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, the driving device 1 exemplified here is a device that microsteps the stepping motor m by a PWM (pulse width modulation) current method in accordance with the input pulse α. In this embodiment, a two-phase stepping motor (phase number N = 2, full step angle x = 1.8 °) is used as the stepping motor m, and a five-phase stepping motor (phase number M = 5, full step angle y = 0.72 °). ) Lead angle can be obtained. In the figure, 10 is a switching unit, 20 is a memory unit, 30 is an address generation unit, 40 is a PWN signal generation unit, 50 is a phase distribution circuit unit, 60 is a phase excitation counter unit, 70 is a resolution setting unit, and 91 is a current power supply circuit. Reference numeral 92 denotes a constant current circuit section. The drive device 1 is configured by these units.

  The stepping motor m is a two-phase stepping motor having a motor structure with a rotor magnetic pole number of 50 and HB, the coil connection method is A and B phase independent type, and four lead wires for the driving device 1 Is attached externally.

  The power supply circuit unit 91 is a circuit in which a power transformer, a rectifying diode bridge, and the like are combined. The input commercial AC is converted into a predetermined level of DC voltage and supplied to each circuit component.

  The constant current circuit unit 92 is a circuit connected between the power circuit unit 91 and the switching unit 10, and the power source current supplied from the power circuit unit 91 to the switching unit 10 is negatively fed back using a transistor or the like. The current is controlled and constant.

  The switching unit 10 is a bipolar drive circuit using switching elements Q1 to Q8 which are NPN transistors, and includes a full bridge circuit 11 of switching elements Q1 to Q4 and a full bridge circuit 12 of switching elements Q1 to Q4. Are used to generate each current flowing in the A-phase and B-phase coils of the stepping motor M.

The excitation signals input to the bases of the switching elements Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are represented by A +, A−, / A +, / A−, B +, B−, / B +, / B
-Is represented as-.

  An excitation sequence for turning on / off the switching elements Q1 to Q8 is as shown in FIG. The current actually flowing through the A phase coil and the B phase coil of the stepping motor m by this excitation sequence is as shown in FIGS.

  4, 6, and 7, “0” to “3” shown in the upper part indicate the number of basic steps, and “0-1” to “3-” shown in the lower part thereof. “2” indicates the number of half steps.

   “PWM A phase → / A phase” in FIG. 6 indicates that the current flowing from the A terminal of the A phase coil to the / A terminal is changed every moment by PWM control. “PWM / A phase → A phase”, “PWM B phase → / B phase” and “PWM / B phase → B phase” are also expressed in a similar manner. “A phase → / A phase” in FIG. 6 means that the current flowing from the A terminal of the A phase coil to the / A terminal is controlled to be constant. “/ A phase → A phase”, “B phase → / B phase” and “/ B phase → B phase” are also expressed in a similar manner. FIG. 6 shows the electrical angle of the stepping motor m.

   That is, as shown in FIG. 7, during the period of basic step 0, the current flowing through the A-phase coil is sequentially changed from the positive direction to the negative direction, and the current flowing through the B-phase coil is maintained at the H level in the positive direction. 1, the current flowing in the A phase coil is maintained at the H level in the negative direction, the current flowing in the B phase coil is sequentially changed from the positive direction to the negative direction, and the current flowing in the A phase coil in the basic step 2 period It is changed sequentially from the negative direction to the positive direction, the current flowing through the B phase coil is maintained at the H level in the negative direction, and the current flowing through the A phase coil at the basic step 3 is maintained at the H level in the positive direction. The current flowing through is sequentially changed from the negative direction to the positive direction.

  Thus, in the basic steps 0 and 2, the magnitude and direction of the current flowing through the A phase coil of the stepping motor m change, and the magnitude of the current flowing through the B phase coil is maintained at the H level or the L level. On the other hand, in basic steps 1 and 3, the magnitude of the current flowing through the A-phase coil is maintained at the L level or the H level, and the magnitude and direction of the current flowing through the B-phase coil changes.

  Of the A-phase and B-phase coils of the stepping motor m, the coil on the side that maintains the current at the H level or the L level in each period of the basic steps 0 to 3 is a current maintaining phase coil, and the basic steps 0 to 3 The coil that changes the current in the period is a current changing phase coil.

  In the memory unit 20, current data necessary for driving the stepping motor m in microsteps is sequentially recorded in advance for each microstep angle. In the present embodiment, the duty ratio data of the PWM waveform necessary for PWM control of the output current of the switching elements Q1 to Q8 related to the current changing phase is recorded for each microstep angle.

  FIG. 2 shows the contents of data recorded in the memory 20 when microstep driving is performed by dividing the stepping motor m by 1000 with respect to the full step angle (1.8 °). The horizontal axis of the graph in FIG. 2 indicates the microstep angle, and the vertical axis indicates the duty ratio of the PWM waveform.

  The data groups indicated by “I” and “II” in FIG. 2 are data necessary for generating the PWM signals related to “PWM (I)” and “PWM (II)” shown in FIG. The current data recorded in the read addresses 0 to 499 belong to the data group “I” (current data of microstep angle θN = 0.000 ° to 0.900 °), while the current data recorded in the read addresses 500 to 999 It belongs to the data group of “II” (current data of microstep angle θN = 0.918 ° to 1.800 °). FIG. 6 shows read addresses of current data on the memory 20 necessary for generating PWM signals related to “PWM (I)” and “PWM (II)”.

  The current data recorded in the memory unit 20 is not represented by a linear formula as in the prior art, but varies as shown in the partially enlarged view of FIG. Specifically, the duty ratio data of the PWM waveform on the memory unit 20 is experimental data obtained by actually driving the stepping motor m by microstep driving and measuring the advance angle. It is finely adjusted every microstep angle (0.0018 ° in the illustrated example) so that it can be rotated with an even division angle in practice.

  The number W of current data on the memory unit 20 is determined by the relationship between the memory capacity and the resolution setting range of the resolution setting unit 70, and is 1000 in this embodiment.

  The resolution setting unit 70 is a switch or the like for setting and inputting a resolution when the stepping motor m is micro-step driven. In this embodiment, the resolution RM corresponding to the lead angle of a five-phase stepping motor having the same lead angle per full step with the two-phase stepping motor can be set and input. As shown in FIG. From 400 to 400 can be set and input in multiple steps. FIG. 3 also shows the resolution RN and lead angle of the two-phase stepping motor corresponding to the resolution RM of the five-phase stepping motor.

  The address generation unit 30 is a circuit unit that sequentially reads current data on the memory unit 22 in accordance with the input of the input pulse α as shown in FIG. In the present embodiment, when sequentially reading the current data from the memory unit 20, the read address is set to the resolution RN obtained by multiplying the resolution RM set by the resolution setting unit 70 by 2.5 (x / y = 5/2). A corresponding number of jumps C (= W / RN) is changed for each input pulse. The read address is increased according to the input of the input pulse α when the direction signal β indicates normal rotation, while it is decreased according to the input of the input pulse α when the direction signal β indicates reverse rotation. In addition, since the number W of current data in the memory unit 20 is 1000, the read address counter overflows due to 1000 inputs of the input pulse α.

  Incidentally, there is a close relationship between the resolution setting range of the resolution setting unit 70 and the number W of current data in the memory unit 20. The number W of current data in the memory unit 20 is a) a value that is a multiple of 5 (= M) and is divisible by the number of jumps C corresponding to the resolution RM (or resolution RN) of the resolution setting unit 70. Or b) a common multiple of 5 (= M) and 2 (= N) and an integer multiple of W (the integer value is A), the resolution RM (or resolution) of the resolution setting unit 70 It is determined according to the rule that it is set to a value that can be divided by the number of skips C corresponding to (RN). On the contrary, when the number W of current data in the memory unit 20 is first determined in relation to the memory capacity or the like, the resolution RM (or resolution RN) range of the decomposition setting unit 70 is the same as that in a) or b) above. It will be decided according to the rules.

  In this embodiment, the resolution RM = 2, 4, 8, 10, 16, 20, 40, 50, 80, 100, 200, and 400 shown in FIG. 3 is determined according to the rule a). The resolutions RM = 1, 2.5, 5 and 25 are determined according to the rule b).

   The resolution RM shown in FIG. 3 is an example, but it can be determined not only according to the rule a) but also according to the rule b). Therefore, the resolution setting range of the resolution setting unit 70 is remarkably increased in this respect. It became wide.

  When the number W of current data is 1000, it is impossible to include the resolution RM = 3 as a target under the rule a) or b). When the resolution RM = 3 needs to be included in the target because of the step angle to be realized, the number of current data on the memory unit 20 is preferably changed to W = 600 or 900.

  The operation of the address generator 30 is as follows. For example, if the resolution RM = 10 is set through the resolution setting unit 70, the advance angle of the stepping motor m is 0.072 ° and the read address jump number C is 40 as shown in FIG. When the direction signal β indicates normal rotation, the read address of the memory unit 20 increases by the jump number C = 40 for each input of the input pulse α. In this process, current data having microstep angles θN of 0.072 °, 0.144 °, 0.216 °, 0.288 °,... Are sequentially read from the memory unit 20. Thereafter, when the microstep angle θN exceeds 1.8 °, 3.6 °, 5.4 °, and 7.2 °, the read address is reset. On the other hand, when the direction signal β indicates reverse rotation, the read address of the memory unit 20 is decreased by the number of jumps C = 40 every time the input pulse α is input, and the same operation as described above is performed.

  The phase excitation counter unit 60 has the number of half steps 0-1 to 3- of the excitation sequence of the stepping motor m shown in FIGS. 4, 6 and 7 according to the resolution RM set through the input of the input pulse α and the resolution setting value 70. 2 is a counter that counts two. The counting direction is the direction indicated by the direction signal β, and the counting result is output to the PWM signal generation unit 40 and the phase distribution circuit unit 50.

  The PWM signal generation unit 40 is a circuit unit that generates a PWM signal having a duty ratio corresponding to the current data read from the memory unit 20. That is, when the current data on the memory unit 20 is read by the address generation unit 30, a PWM signal ("PWM (I)" or "PWM (II) having a PWM waveform having a duty ratio equal to the read data is obtained. ) ") Is generated and output to the phase distribution circuit unit 50.

  The phase distribution circuit unit 50 outputs the PWM signal output from the PWM signal generation unit 23 in the phase distribution pattern shown in FIG. 4 corresponding to the half step numbers 0-1 to 3-2 of the excitation sequence indicated by the phase excitation counter unit 60. In addition, the switching element Q1 is divided by the phase-distributed excitation signals A +, A-, / A +, / A-, B +, B-, / B +, / B- while distributing the H level signal and the L level signal. , Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are turned on and off. The H level signal and the L level signal are generated by the phase distribution circuit unit 50.

  Here, the H level signal means a signal having a voltage level at which the switching element Q1 and the like are completely activated, and the L level signal completely brings the switching element Q1 and the like into an inactive state. A signal having a level voltage.

   “H” in FIG. 4 indicates that an H level signal is distributed to each excitation signal for each half step, and for “L” in FIG. 2, an L level signal is provided for each half step. It shows that the excitation signal is distributed. As for “PWM (I)” and “PWM (II)” in FIG. 4, the PWM signals related to “PWM (I)” and “PWM (II)” generated by the PWM signal generation unit 40 are the excitation signals. To be distributed. FIG. 5 shows the waveform of each excitation signal at a predetermined timing during the half step 0-1. T in FIG. 5 indicates a PWM cycle.

  In the case of the driving device 1 configured as described above, the current data recorded in the memory unit 20 is finely adjusted for each microstep angle. As a result, when the stepping motor m is driven by the microstep, the angle The uniformity of the division is maintained, and accordingly, it becomes possible to increase the accuracy of driving the motor. Of the switching elements Q1 to Q8 related to the fine current control necessary for microstep driving, only a part of the PWM signal is distributed, and an H level or L level signal is distributed for the other parts. Therefore, the configuration relating to the fine current control is simplified and high torque can be obtained. Furthermore, since the advance angle of the five-phase stepping motor is realized while actually using the two-phase stepping motor, it is possible to achieve a significant cost reduction of the entire apparatus including the stepping motor.

  Next, a modification of the excitation sequence of the drive device 1 will be described with reference to FIGS. The description will focus on differences from the example shown in FIG. 1 and the like, and the description of common parts will be omitted. 8 and 9 correspond to FIGS. 4 and 5 in the above example, respectively.

  The excitation sequence employed in the phase distribution circuit unit 50 is as shown in FIG. 8, and the waveforms of the excitation signals at the predetermined timing during the half step 0-0 are as shown in FIG. In FIG. 9, T represents the PWM cycle. “Had” and “Lad” in FIG. 8 indicate that signals having an H level signal and a signal close to an L level signal and having a finely adjusted voltage level are assigned.

  When the half step number of the excitation sequence indicated by the phase excitation counter 60 is 0-0, during that period, the PWM signal related to “PWM (I)” is distributed to the excitation signal A +, and the L level signal is the excitation signal. A-, / A + and / A- are respectively distributed, "Had" signals are respectively distributed to excitation signals B- and / B +, and "Lad" signals are respectively distributed to excitation signals B + and / B-. . In this case, the switching element Q1 is controlled for each microstep, the switching elements Q2 to Q4 are in an active state or inactive state, and the switching elements Q5 to Q8 are in an active state or near inactive state.

  When the number of half steps of the excitation sequence indicated by the phase excitation counter unit 60 is 0-1, during that period, the PWM signal related to “PWM (II)” is distributed to the excitation signal / A +, and the L level signal is excited. The signals A +, A− and / A− are respectively distributed, the “Had” signal is respectively distributed to the excitation signals B− and / B +, and the “Lad” signal is respectively distributed to the excitation signals B + and / B−. . In this case, the switching element Q3 is controlled for each microstep, the switching elements Q1, Q2, and Q4 are in an active state or inactive state, and the switching elements Q5 to Q8 are in an active state or nearly inactive state. The same applies to the case where the number of half steps of the excitation sequence indicated by the phase excitation counter unit 60 is 1-1 to 3-2.

  The excitation sequence is sequentially changed to half steps 0-1, 0-2, etc., and the switching elements Q1 to Q8 are switched by the excitation signal A + or the like. As a result, the A phase and B phase coils of the stepping motor M are switched. The magnitude of the current flowing and its change are exactly the same as those shown in FIGS.

  As described above, the phase distribution circuit unit 50 outputs not only H level and L level signals but also “Had” and “Lad” signals as shown in FIG. In the present embodiment, the signals “Had” and “Lad” are PWM signals as in “PWM”, but are different from the signals in “PWM” in that the duty ratio is not adjusted for each microstep angle. . The duty ratios of the signals “Had” and “Lad” can be adjusted by a current balance adjusting unit 80 shown in FIG.

  The current balance adjusting unit 80 is a switch or the like for finely adjusting the duty ratio of each signal of “Had” and “Lad”. That is, the duty ratio of each signal of “Had” and “Lad” generated by the phase distribution circuit unit 50 through the current balance adjustment unit 80 is finely adjusted. As a result, the A phase coil or B phase coil of the stepping motor m The magnitude of the current related to the current maintenance phase can be finely adjusted.

  According to the modification configured as described above, the following effects can be obtained. In the driving device 1 shown in FIG. 1 and the like, the stepping motor m has different characteristics due to variations in characteristics such as residual magnetic characteristics, winding resistance, and inductance of each phase coil of the stepping motor m and variations in characteristics of the output stage of the driving device 1. The balance between the current related to the current changing phase and the current related to the current maintaining phase cannot be made appropriate, and as a result, the desired step angle cannot be obtained simply by controlling the current related to the current changing phase. There is. In this regard, in the case of the driving device 1 according to the modification, since the current related to the current maintaining phase is fine-tunable with constant current control, when the current related to the current maintaining phase is finely adjusted in the ± direction, Accordingly, the current related to the current changing phase changes in the opposite direction. This is irrelevant whether or not the midpoint of the stepping motor m is connected. As a result, the balance between the current related to the current changing phase and the current related to the current maintaining phase can be made appropriate, and as a result, the advance angle at the time of microstep driving becomes accurate. Therefore, it is possible to improve the accuracy of the micro step drive without being greatly affected by the characteristics of the stepping motor m and the variations in the output stage of the drive device 1.

  Note that the stepping motor driving apparatus according to the present invention may be appropriately changed according to the object to be driven, regardless of the number of phases of the stepping motor, the phase coil connection method, the excitation sequence, and the like. In particular, the lead angle of the three-phase stepping motor can be realized by the same method as described above using a two-phase stepping motor. That is, the advance angle of a stepping motor having a phase number different from that of the stepping motor to be used can be realized in the same manner. For the memory unit, the number of current data, the current value, and the like may be appropriately changed as long as current data necessary to drive the stepping motor in microsteps is sequentially recorded in advance for each microstep angle. As long as the resolution setting unit is configured to be able to set and input the resolution for driving the stepping motor in microsteps, the resolution of two or more types of stepping motors having different numbers of phases can be used regardless of the setting input method. Setting input may be made possible. As long as the address generation unit is configured to sequentially read current data on the memory unit according to the input of the input pulse, the same function may be realized using software regardless of the circuit configuration. In order to realize the lead angle of the stepping motor that is actually used, the read address may be changed for each input pulse by the number of jumps corresponding to the resolution set through the resolution setting unit. As long as the PWM signal generation unit generates a PWM signal having a duty ratio corresponding to the current data read from the memory unit, the same function is realized using software regardless of the signal waveform or circuit configuration. May be. For the phase excitation counter unit, the same function can be realized using software regardless of the circuit configuration as long as the number of steps such as full step, half step, or division step of the excitation sequence is counted according to the input of the input pulse. good. As for the phase distribution circuit unit, as long as the phase distribution pattern corresponding to the number of steps indicated by the phase excitation counter unit distributes the PWM signal to generate each phase excitation signal, the type of signal to be phase distributed, the phase distribution pattern, The same function may be realized using software regardless of the circuit configuration. As long as the switching unit has a switching element and can generate each phase current of the stepping motor by turning on and off each switching element according to the phase excitation signal, the type and circuit configuration of the switching element are questioned. Absent.

1 Drive unit (Stepping motor drive unit)
DESCRIPTION OF SYMBOLS 10 Switching part Q1-Q8 Switching element 20 Memory part 30 Address generation part 40 PWM signal generation part 50 Phase distribution circuit part 60 Phase excitation counter part 70 Resolution setting part 80 Current balance adjustment part m Stepping motor

Claims (6)

In a PWM current control type stepping motor driving device, current data necessary for microstep driving of the stepping motor is sequentially recorded in advance for each microstep angle, and on the memory unit according to input pulse input. An address generator for sequentially reading current data, a PWM signal generator for generating a PWM signal having a duty ratio corresponding to the current data read from the memory, and counting the number of steps of the excitation sequence according to the input pulse input A phase excitation counter unit, a phase distribution circuit unit for phase-distributing the PWM signal in a phase distribution pattern corresponding to the number of steps indicated by the phase excitation counter unit to generate each phase excitation signal, and a plurality of switching elements In addition, each switching element is turned on / off according to the phase excitation signal to change the stepping mode. Comprising a switching unit for generating each phase current of motor, the switching element is in an active state, H-level when it is inactive, and a current balance adjustment unit that enables fine adjustment of the respective current values of the L level, the The stepping motor driving apparatus characterized in that the memory unit finely adjusts current data in advance for each microstep angle so that a stepping motor that is actually used can rotate at an equal division angle.   2. The stepping motor drive device according to claim 1, wherein the phase distribution circuit unit includes an H signal in addition to the PWM signal generated by the PWM signal generation unit with a phase distribution pattern corresponding to the number of steps indicated by the phase excitation counter unit. A stepping motor driving apparatus characterized in that a phase excitation signal is generated by phase-distributing a level signal and an L level signal. 2. The stepping motor driving apparatus according to claim 1, further comprising a resolution setting unit for setting and inputting a resolution for microstep driving of the stepping motor, wherein the address generation unit sequentially reads current data from the memory unit. The stepping motor driving apparatus is characterized in that the read address is changed for each input pulse by the number C of jumps corresponding to the resolution . 4. The stepping motor drive device according to claim 3, wherein the stepping motor has N (N ≧ 2) phases, and the resolution setting unit has a common lead angle per step with the N-phase stepping motor. The resolution RM corresponding to the lead angle of the M (M ≠ N) phase stepping motor to be set can be set and input. The full step angle of the N phase stepping motor is set to x, and the full step of the M phase stepping motor is set. When the angle is y, the address generation unit reads the current data from the memory unit in order to read the input address by the number of jumps C corresponding to the resolution RN obtained by multiplying the resolution RM by x / y. A stepping motor driving device characterized in that it is configured to change for each input . 5. The stepping motor driving apparatus according to claim 4, wherein the memory unit is set to a value that allows the number W of current data to be a multiple of M and to be divisible by a jump number C corresponding to the resolution of the resolution setting unit. stepping motor driving apparatus characterized by there. 5. The stepping motor driving apparatus according to claim 4, wherein the memory unit is configured such that the number W of current data is a common multiple of M and N, and an integer multiple of W is divisible by a jump number C corresponding to the resolution of the resolution setting unit. Is set to a possible value . A stepping motor driving apparatus characterized in that

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