Abstract: A method for controlling a stepping motor that moves an object from an initial position by a target distance. The method includes calculating a moved distance of the object, calculating a remaining moving distance of the object, updating a first velocity value until the moved distance exceeds a first reference value, updating a first position value indicating the present position of the accelerated object by adding the updated first velocity value to the first position value, updating a second velocity value when the remaining distance is less than the second reference value by subtracting a second acceleration value from the second velocity value, and updating a second position value indicating the present position of the decelerated object by adding the updated second velocity value to the second position value.

Abstract: The controller comprises current sensors for detecting motor currents, an inverter containing a current control means for feeding currents to motor windings, a coordinate transformer that transforms the motor currents in a fixed coordinates system into currents in a first rotational coordinates system, and an angle calculator that transforms a command pulse into a command angle. A second rotational coordinates system composed of a dp axis and a qp axis perpendicular to the dp axis is determined from the command angle. A command current on the dp axis is set to be a value corresponding to a motor current amplitude and another command current on the qp axis is set to be zero. The motor current is projected on the dp and qp axes and controlled so as to make the components on the dp and qp axes coincide with the respective command currents on the dp and qp axes.

Abstract: The invention relates to a mains-commutated, synchronous AC motor (1) with permanent-magnet excitation, which is configured as an external-rotor motor with a permanent-magnet external rotor (6) which rotates around an inner stator. In this case, an electronic starting apparatus (2) is provided which actuates the stator (4) in order to start the external rotor (6) in such a manner that the external rotor (6) is accelerated in a controlled manner to its synchronous rotation speed, and then continues to run in the mains-commutated synchronous mode.

Abstract: A system for programming and controlling the movement of a probe of a voice coil actuator along a path includes a control module that is mounted on a voice coil actuator. Specifically, the control module is connected to a clock and to an encoder to selectively establish a plurality of sequential positions for the probe. Each position in this sequence is defined by a location on the path (translation and rotation), and a time at the location. More specifically, the control module includes a key pad for inputting data to identify each position and also, there is a display for providing a visual presentation of the data. In operation the plurality of sequential positions specify a work cycle for the probe and the voice coil actuator uses the input data to perform a series of work cycles.

Abstract: The invention relates to a device for producing and controlling an alternating current with a direct current source in at least one inductive load, in particular for driving a stepper motor, preferably in microsteps.

Abstract: A vehicle lamp system 1 having a leveling mechanism 2 for controlling the posture of a reflector RF and a stepping motor 3 as a driving source of the leveling mechanism. The lamp system has a detector 5 which may determine whether an external force, such as a vibration or a shock is given to the reflector RF or if there is a possibility that the vibration or shock may be given to the reflector. A rotor is prevented from being deviated from the original position by exciting each phase coil of the stepping motor with the same excitation phase as the last excitation phase at the time when the stepping motor 3 was last driven or otherwise a coil in only one of the last excitation phases at the time when the stepping motor 3 was last driven, and before vibration or a shock is given to the reflector RF after the coils in the respective phases are totally set to a non-excited condition in the stepping motor 3.

Abstract: A digital encoder control method of a digital control apparatus has a driving unit, a frequency signal generating unit for generating a pulse signal of a frequency according to a driving velocity of a driven member which is driven by the driving unit, an edge detecting unit for detecting a rising-up edge and a falling-down edge of the pulse signal, and a period data detecting unit for counting period data between edges detected by the edge detecting unit. Each time the edges are detected by the edge detecting unit, the period data between the same edges as the detected edges is outputted as control velocity data of the driving unit.

Abstract: The stepping motor controller comprising an excitation signal generator, a switching circuit, a PWM constant current control circuit and a current sensor further comprises a motor detector circuit that transmits a control signal for generating a constant current for a predetermined time for detecting the motor, a constant current generator that receives the control signal and generates the constant current to be supplied to the winding, a reference voltage generator that generates a reference voltage, a voltage comparator circuit that compares the reference voltage with a voltage drop at the winding, and a current value setting signal generator circuit that transforms an output of the voltage comparator circuit into a current value setting signal for the PWM constant current control circuit. An output of the current value setting signal generator circuit is connected to a current value setting terminal of the PWM constant current control circuit.

Abstract: To prevent erroneous detection when a step motor is not rotated by a simple constitution. A control circuit controls to make a transistor to ON/OFF in a rotation detection period immediately after finishing a drive pulse in a state in which transistors is made ON. A comparator compares detection voltage produced at a connection point OUT2 between a resistor for detection and a coil with threshold voltage Vss, determines that a step motor is rotated when the detection voltage is equal to or lower than Vss and determines that the step motor is not rotated when the detection voltage is not equal to or lower than Vss. In this case, current ia does not flow immediately after finishing the drive pulse and therefore, the detection voltage produced at the connection point OUT2 becomes voltage having a polarity reverse to that of the threshold voltage Vss and does not become equal to or lower than Vss and therefore, the comparator determines that the step motor is not rotated.

Abstract: A method for controlling a stepping motor that moves an object from an initial position by a target distance. The method includes calculating a moved distance of the object, calculating a remaining moving distance of the object, updating a first velocity value until the moved distance exceeds a first reference value, updating a first position value indicating the present position of the accelerated object by adding the updated first velocity value to the first position value, updating a second velocity value when the remaining distance is less than the second reference value by subtracting a second acceleration value from the second velocity value, and updating a second position value indicating the present position of the decelerated object by adding the updated second velocity value to the second position value.

Abstract: In an electronic apparatus including a generator device for generating power, a storage device for storing the generated electric energy, and a motor driven by the electric energy stored in the storage device, it is detected whether a magnetic field is generated by power generation. If it is detected that a magnetic field is generated by power generation, a correcting driving-pulse signal having an effective power larger than a normal driving-pulse signal, which is output for controlling the driving of the motor, is output to the motor. In performing this operation, a determination is made by assuming that a magnetic field is generated while the storage device is in the charging state.

Abstract: In an image forming apparatus, change in electrical current value flowing through an exciting coil of a motor is measured for a predetermined time period, and, if a measurement result of the change in electrical current value obtained by the measuring means by the measurement for the predetermined time period exceeds a predetermined value, it is judged that loss of synchronism is generated. There are provided loss of synchronism detecting means, sheet detecting means disposed in a sheet conveying path of a sheet conveying system driven by the motor, and jam detecting means for judging that jam is generated if a sheet detecting condition of the sheet detecting means is continued for a certain time period or if the sheet is not detected by the sheet detecting means while the motor is being driven.

Abstract: A device is provided for chopping a control signal of an initial excitation phase or a final excitation phase by a predetermined cycle during low speed rotation control of an excitation phase control signal (excitation control signal) of a stepping motor when acceleration control and deceleration control of the stepping motor are effected, thereby reducing an excessively great driving current created during low speed rotation of the stepping motor, particularly the initial retaining excitation period during acceleration control and the final retaining excitation period during deceleration.

Abstract: A stepper motor controlling apparatus having a storing unit storing driving data for generating a stepper motor driving phase signal in each of plural controlling circuits, which share the driving data in the storing unit, thereby decreasing the total amount of the driving data. It is therefore possible to minimize the required capacity of the storing unit required for the driving data.

Abstract: This invention provides a scanner, which is capable of scanning document images based on a stepping control table and a method to generate such a table. This scanner includes a scanning module to scan a document and generates a responding image signal, a stepping motor to drive the scanning module or the document and a control device to control the operation of the scanning module and the stepping motor. This control device includes a stepping control table, which contains the stepping numbers for the stepping motor to drive the scanning module or the document. While scanning a document, this device will accurately control the stepping motor according to the stepping numbers relating to the locations of the lines to be scanned, and further move the scanning module or the document to a pre-defined position for a scanning task. A design like this will reduce errors in a scanning module's movement caused by the mechanical deviation.

Abstract: An available input of to a motor controller is used to measure the motor power supply voltage. Typically, a scaled down version of the voltage is sensed. The microprocessor is used to calculate the motor control current, in that case, is then calculated from the scaled down version. A scale factor that depends upon the sensitivity of the motor current to the motor supply voltage is calculated by the microprocessor. Driving parameters in the controller are then adjusted to account for the scale factor. In a preferred embodiment, the driving parameters are PWM parameters, and the microprocessor multiplies the measured power supply voltage to obtain a scale factor that can then be multiplied by the nominal PWM values to obtain the new PWM values.

Abstract: A motor failure detecting module and a motor driving circuit with the module are proposed. The driving circuit includes a sensing unit, a comparator, an AND gate, a switch and a failure detecting module. The sensing unit is to measure the current flowing through the motor and generating a detecting voltage. The comparator is used to compare the detecting voltage with a reference voltage and generate a compared signal. The AND gate receives the compared signal and a control signal and generates a motor driving signal to control the switch. The switch controls the coils of the stepping motor. And the failure detecting module is used to detect whether the motor is failure according to the frequency and/or duration of the compared signal.

Abstract: During the actuation of the flap, the drive frequency of the stepper motor is reduced as a function of the requirements for torque delivered by the motor in order to shift the flap. To that end, information is continuously gathered representing the requirements for torque delivered by the motor in order to shift the flap, the drive frequency is reduced, if appropriate, in response to a detected increase in the torque requirements and, when the drive frequency is below a predetermined maximum frequency, the drive frequency is increased, if appropriate, in response to a detected reduction in the torque requirements.

Abstract: The invention is a low-cost stepper motor drive system comprising a microstepping motor and a logic circuit. The logic circuit includes two integrated circuits for controlling one or more phases of the microstepping motor. Each one of the integrated circuits is a motor driver capable of producing up to sixteen microsteps per full step. Further, each one of the integrated circuits takes a set of analog/digital bits and a phase bit as input. Additionally, within the logic circuit, there is included a microcontroller for controlling the microstepping motor. The microcontroller comprises six control bits, which direct the controller in outputting a set of step sequences to the integrated circuits.

Abstract: In a motor drive control apparatus, without using a current control circuit, a gate circuit, and a minus power supply, a short period (a period in which either one of Nch and Pch FETs is turned on without supplying currents from the FET elements to coils of a motor at the same time at electrical power supply points) is provided between one cycle of duty control of the FET elements and the next cycle, and a total current flowing to the motor is controlled by controlling a width of the period.

Abstract: In a drive apparatus, an operating member is driven by a step motor under control of a control section in response to a signal from a detection section. The control section sets the operating member to an initial position from a mechanically stopped position by forward rotating the step motor at a predetermined step number. At a time of starting an operation of the operating member from the initial position, the control section temporarily reverse rotates the step motor to move the operating member to a detection zone so that the detecting section may detect the signal when the operating member performs a normal movement. Then, the control section responds to the signal to forward rotate the step motor so as to move the operating member to a target position.

Abstract: A method for controlling a step motor of a scanner by using three sets of parameters is provided. The three sets of parameters include a pulse count number PCN, a count base CB, and a motor constant speed interval MCSI. The method includes the follow steps. First, generate a synchronous trigger signal in correspondence with each exposure trigger signal CVTR generated by an image sensing module of the scanner and clear a base accumulator BA. Then, add the count base CB to the base accumulator in correspondence with each reference pulse. Finally, generate an asynchronous trigger signal and clear the base accumulator when the base accumulator is greater than or equal to the pulse count number PCN. Since the speed of the step motor only relates to the pulse count number PCN and the count base CB, the step motor can be controlled by only setting these parameters.

Abstract: A motor combination system with operating method for operating as an induction motor or a stepping motor is disclosed. The disclosed system basically encompasses a switch device, an induction motor control module, and a stepping motor control module. Driving signals generated by the induction motor control module and the stepping motor control module are fed into the switch device. The induction motor control module receives a feedback signal for compensating simulation distortion when the disclosed system operates as an induction motor. The switch device is responsive to a mode selection signal to decide which driving signals being selected for driving the disclosed system for operating. In the beginning, the disclosed system operates as a stepping motor for providing torque enough for switching purpose. According to the mode selection signal, the disclosed system may switch to operate as an induction motor when the torque is large enough.

Abstract: A method and apparatus for automatically detecting an occlusion or drive system failure in a medication infusion system is provided. The electrical current to an infusion pump is measured and compared against a baseline average current. If the current exceeds a threshold amount, an alarm is triggered. Alternatively, pump motor encoder pulses are measured during a pump cycle. If the number of pulses do not correspond within a normal range, an alarm is triggered. After any alarm is triggered, the pump motor is driven in reverse for an incremental distance in order to relieve the fluid pressure in the system.

Abstract: A stepping motor with an electrical activation circuit for electrical control of its exciter windings, is made as a driving motor and also as a braking motor with an adjustable braking action. The predefinable braking action is achieved passively without any current feed into the exciter windings. For this purpose a stipulated impedance with an adjustable duty factor can be connected to each exciter winding. One such stepping motor that is controlled in its braking action is used in an arrangement in which a strip or filament material can be transported braked from a storage.

Abstract: A stepper motor is initialized so that the exciting signal is applied to coils with the step shifted by the half of a one electric cycle from the rebounding step being synchronized with the timing when the stopper piece is brought into contact with a fixed stopper. The rebounding step, in which the rotor of the stepper motor reverses its rotating direction, can be easily detected. If the rebounding step can be detected, the position for initializing can be easily defined in the angle shifting manner as described above.

Abstract: A method and apparatus for automatically detecting an occlusion or drive system failure in a medication infusion system is provided. The electrical current to an infusion pump is measured and compared against a baseline average current. If the current exceeds a threshold amount, an alarm is triggered. Alternatively, pump motor encoder pulses are measured during a pump cycle. If the number of pulses do not correspond within a normal range, an alarm is triggered. After any alarm is triggered, the pump motor is driven in reverse for an incremental distance in order to relieve the fluid pressure in the system.

Abstract: The stepping motor controller comprising an excitation signal generator, a switching circuit, a PWM constant current control circuit and a current sensor further comprises a motor detector circuit that transmits a control signal for generating a constant current for a predetermined time for detecting the motor, a constant current generator that receives the control signal and generates the constant current to be supplied to the winding, a reference voltage generator that generates a reference voltage, a voltage comparator circuit that compares the reference voltage with a voltage drop at the winding, and a current value setting signal generator circuit that transforms an output of the voltage comparator circuit into a current value setting signal for the PWM constant current control circuit. An output of the current value setting signal generator circuit is connected to a current value setting terminal of the PWM constant current control circuit.

Abstract: In an FDD control apparatus for controlling a floppy disk drive for driving a floppy disk loaded in the floppy disk drive, an FDD control part including a floppy disk controller (FDC) is disposed in an FDD side in lieu of a host side (a SET side). The host side (SET side) is loaded with a USB connector connected to the FDD control part. The FDD control part includes a flash ROM for storing a program for adjusting a step timing of a stepping motor.

Abstract: A DC motor control device and a DC motor control method are configured to calculate driving motion time and DC motor current flow per unit time, or DC motor total current flow and driving motion time, every continuous driving motion of the DC motor, and interpose a drive stopping time to stop the DC motor for a time corresponding to the calculated value every time before a subsequent driving motion starts. Alternatively, they are configured to interpose a drive stopping time to stop the DC motor for a time calculated by cumulating such time corresponding to the calculated value over a plurality of occurrences every time before a subsequent block of driving motions starts after each block of driving motions.

Abstract: A scanner determines whether a target is a bar code symbol and, if so, whether that symbol is one-dimensional or two-dimensional. For two-dimensional symbols, the scanner aligns a scanning pattern with the symbol and expands the scanning pattern to reach only to the top and bottom edges of the symbol, not beyond. The scanner also has a microprocessor-control scanning engine that uses a coil to drive a scanning element and pick up feed back signals from the scanning element. A pulse-width-modulated regulator also provides fast and efficient operation for driving the coil. The scanning engine can also be designed to generate a pattern that precesses across the target, and a powerful interface to the scanning engine allows decoding and control logic to work efficiently with and independently of the scan engine.

Abstract: In a method and device for controlling several stepping motor modules in printing or copying machines, sets of ramp data are centrally calculated in a computer in a calculation phase and are transmitted via a bus system to one logic unit each in a loading phase. The ramp data are stored in the stepping motor modules in non-volatile memories and are loaded to corresponding main memories depending on operating conditions. When a stepping motor module is operational, the current set of ramp data is transmitted by a control unit. A start signal transmitted by the control unit initiates the conversion of the set of ramp data selected in the corresponding logic unit into impulses of variable distance.

Abstract: A control device for stepping motor including a driving pulse supplying unit for supplying a plurality of driving pulses to a driving coil for driving a rotor. A rotation detecting pulse supplying unit supplies rotation detection pulses for detecting whether the rotor rotated. A magnetic field pulse supplying unit supplies a plurality of magnetic field detection pulses for detecting the presence of magnetic field external to said stepping motor. A detection unit determines whether the driving rotor rotated and whether a magnetic field is present. An auxiliary pulse supplying unit supplies an auxiliary pulse when either rotor was not detected or when said an external magnetic field was detected. Before the driving pulse, is output, two said magnetic field detecting means magnetic field detecting pulses having different polarities are output.

Abstract: A speed control device, whereby individual motor phases of an electronically commutated multiphase electric motor are supplied via corresponding individual phase shifters from a constant voltage supply unidirectionally and unpulsed during time blocks which are derived from stored time block pulse patterns specific to certain speeds. The speed control device permits setting a variety of speeds with relatively little expense and with low operating losses. The speed control device further provides a simple device for setting intermediate speeds by means of low-frequency switching between at least two time block pulse patterns.

Abstract: A rotor composite type three-phase stepping motor having a stator consisting of two stator elements each having 6 n pieces of stator magnetic pole with Ns pieces of pole tooth formed on the tip end of each stator magnetic pole piece, and a permanent magnet held by the two stator elements therebetween, a rotor of magnetic material arranged so as to face to a periphery of the stator through an air gap, Nr pieces of pole tooth being formed on a periphery of the rotor, and exciting windings wound around each stator magnetic pole piece of the stator elements consisting of two sets of three-phase windings each wound around 3n pieces of stator magnetic pole among the 6 n pieces of stator magnetic pole.

Abstract: A step motor drive control circuit, which is suitably employed in an image scanner, reduces the uneven rotation characteristics of a step motor and improves the scanning quality in the image scanner. The step motor drive control circuit generates a phase signal for driving the step motor from a phase signal generator in accordance with a driving pulse signal. The step motor drive control circuit controls switching devices of a driver in accordance with the phase signal so as to perform bipolar driving of the step motor. The step motor drive control circuit includes at least two switching devices with different switching characteristics in order that bipolar driving of the step motor is performed. A constant-current signal from a constant-current signal generator is added to the switching devices, thereby setting switching characteristics of the switching devices to be uniform.

Abstract: The present invention regards an electronic device for controlling the electromagnetic self-braking current in reversible rotating electric commutator machines, fitted with an inductor winding and an armature winding, in which there are reversing means to control the functioning of the electric machine as a generator by mutual inversion of the polarity of said inductor winding and said armature winding. The device includes a switchable current control circuit and an excitation circuit distinct from each other. The control circuit includes an electric load, a power device for connecting and disconnecting said electric load in series in the input circuit of said inductor winding to dissipate the power produced by said electric machine when it functions as a generator, and a variable duration pulse generator for controlling the switching of said power device.

Abstract: In an image forming apparatus, change in electrical current value flowing through an exciting coil of a motor is measured for a predetermined time period, and, if a measurement result of the change in electrical current value obtained by the measuring means by the measurement for the predetermined time period exceeds a predetermined value, it is judged that loss of synchronism is generated. There are provided loss of synchronism detecting means, sheet detecting means disposed in a sheet conveying path of a sheet conveying system driven by the motor, and jam detecting means for judging that jam is generated if a sheet detecting condition of the sheet detecting means is continued for a certain time period or if the sheet is not detected by the sheet detecting means while the motor is being driven.

Abstract: A DC motor control device and a DC motor control method are configured to calculate driving motion time and DC motor current flow per unit time, or DC motor total current flow and driving motion time, every continuous driving motion of the DC motor, and interpose a drive stopping time to stop the DC motor for a time corresponding to the calculated value every time before a subsequent driving motion starts. Alternatively, they are configured to interpose a drive stopping time to stop the DC motor for a time calculated by cumulating such time corresponding to the calculated value over a plurality of occurrences every time before a subsequent block of driving motions starts after each block of driving motions.

Abstract: A stepper motor control system is disclosed. The stepper motor including a rotor positioned within a stator for relative motion. The stepper motor further includes a control system associated with the stator and rotor for controlling relative motion. The control system is a resonant circuit which conserves electrical charge includes a first winding positioned between a first electrical charge source and a first capacitor assembly; a first switch controlling the flow of electrical charge between the first electrical charge source and the first capacitor assembly through the first winding in a first direction; and a second switch controlling the flow of electrical charge from the first capacitor assembly and through the first winding in a second direction. In use, phase one begins with the opening of the first switch, causing the flow of electrical charge through the first winding in a first direction and a predetermined relative movement between the stator and rotor.

Abstract: A CPU for a motor driving apparatus of an image forming apparatus excites a predetermined phase winding among plural phases of a stepping motor for a predetermined time period. Thereafter, before a rotation of the motor is started, it is judged whether there is the possibility of deviating a positional relationship between a rotor and a stator of the motor from a positional relationship determined by the excitation of the predetermined phase winding for the predetermined time period, by an external force, on the basis of judgement whether a door is opened for jam treatment. If the possibility of deviation is judged, the predetermined phase winding among plural phases of the stepping motor is excited again for a predetermined time period.

Abstract: A lens controlling apparatus includes a lens-driving stepping motor, a driving current forming circuit for forming a driving current waveform to be supplied to the stepping motor, an inputting circuit for inputting a stop instruction to stop the lens-driving stepping motor, a stopping circuit for performing the operation of stopping the stepping motor in accordance with the stop instruction, a phase detecting circuit for detecting the phase of the driving current waveform to be supplied to the stepping motor, and an inhibiting circuit for inhibiting the stop instruction from being executed except when the phase of the driving current waveform detected by the phase detecting circuit is a predetermined phase.

Abstract: A method and apparatus for driving a stepper motor such that when the motor is stepped, the velocity of the motor is substantially zero upon reaching a new stepped position, thereby eliminating overshoot and ringing, and the wasted energy associated with these effects. The method comprises energizing at least one of the stepper motor windings at a predetermined current level for a predetermined step time, wherein the current level is determined as a function of the step time and dynamic single-step response characteristics of the stepper motor and load so that the motor velocity is substantially zero when the adjacent stepped position is reached. At this point, the stepper motor windings that were energized to make the rotor of the motor move are de-energized, whereupon the rotor is held in place by the inherent detent torque of the stepper motor. Since the velocity of the motor is substantially zero when the adjacent stepped position is achieved, there is no overshoot, and thus ringing is eliminated.

Abstract: A process is disclosed for recognizing the step of stepping motors by analyzing the current that flows through the motor, without using any sensors. In order to overcome the problems caused by the use of a shunt resistance, the resulting current measurement errors and toggling, and to ensure an as disturbance-free and reliable operation as possible in all operation states of both unipolar and bipolar stepping motors, the disclosed process has the following steps: a defined current is transmitted to a motor winding after a reversal of the current flow direction in a first motor winding; a motor winding connection is switched with a high ohmic value; the response signal at the motor winding connection switched with a high ohmic value is sensed; the length of the response signal is evaluated. Alternatively, triggering is provoked by an external triggering signal, independently of the reversal of the current flow direction.

Abstract: A stage apparatus for moving a table, on which a work is carried, of a semiconductor producing equipment or the like on a base by way of a driving shaft and positioning the table at a predetermined position. The stage apparatus comprises a guide mechanism for guiding and supporting the table on the base; a linear motor provided between the base and the table along a direction in which the table is fed; and controlling means for controlling, for a predetermined period before the table is stopped, stopping operations of the driving shaft and the linear motor in a mutually associated relationship in accordance with predetermined controlling conditions.

Abstract: A position control apparatus includes a stepping motor, a lead screw arranged to be rotated by the stepping motor being driven, a moving member arranged to move according to rotation of the lead screw, a first detecting device which detects that the moving member passes a particular position, a second detecting device which detects that the lead screw passes a particular rotating position, and a determination device which determines an amount of deviation of the moving member from a reference position on the basis of outputs from the first detecting device and the second detecting device.

Abstract: A step-motor-driving device includes (a) a step-motor having driving-windings in plurality of phases, (b) an exciter for supplying power to excite driving-windings, (c) a position detector for detecting a position of a mover of the motor and outputs a position-detecting-signal, and (d) an excitation-timing-controller for receiving a driving-instruction-signal and a position-detecting-signal, and outputs an exciting signal to the exciter responsive to an input of one of the driving-instruction-signal and the position-detecting-signal.

Abstract: In an electronic device having a stepping motor which can be driven more quickly than in a normal driving operation without causing a significant increase in power consumption, a detecting coil control circuit is provided which controls a connection circuit serving to open and close a detecting coil that is wound coaxially with a driving coil, in such a manner that the detecting coil is opened during the period in which a quick driving pulse is supplied to the driving coil. After supplying the quick driving pulse, a driving controller controls a driving circuit so as to open the driving coil, while the driving controller closes the detecting coil so that a voltage induced in the detecting coil by an electromotive force is detected by a position detecting circuit thereby determining the position of a rotor. The chance that the driving coil and the detecting coil act as electromagnetic brakes is minimized thereby ensuring that the quick driving operation is performed with low power consumption.

Abstract: A stepping motor control unit is capable of driving a stepping motor fast through feedback control. Slits bored in a disk fixed to a rotor of a stepping motor are located at positions that precede magnetically stable positions of the rotor in a direction of rotation of the rotor. Light passing through the slits is detected by an optical sensor, and a signal t is output thereby. The signal t is delayed by a predetermined time according to the rotating speed of the rotor and then transmitted to a control unit. The control unit receives a position detection signal earlier according to the rotating speed of the rotor. Therefore, the wait time required for switching phases can be shortened. Moreover, when the signal t is generated twice or more during a signal t detection time during which a signal t indicating a certain phase is detected, the second and subsequent signals t are ignored. Thus, incorrect detection can be avoided.

Abstract: A driving apparatus of a stepping motor has a simplified circuit structure and a bipolar driving system. The stepping motor has two exciting coils, which are driven by respective bridge circuits. Transistors provided respectively on two sides of one of the bridge circuits are commonly used by both of the bridge circuits. Accordingly, the driving circuit is formed with a reduced number of transistors.