JPS61116998A - Circuit device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Applicability] The present invention has two half-windings per phase, and each half-winding of each phase is in series with the switch to be controlled. , is connected to the supply voltage of the step knob motor and further has a current sensor for the step motor current, the output signal of the current sensor is led to a comparator, the output signal of the comparator is The present invention relates to a circuit arrangement for controlling a unipolar step motor, referred to as controlling a step motor current.

[Conventional technology]

A circuit arrangement for controlling both half-windings of a unipolar stepper motor using controlled switches comprises:
``Schriftmotoren Aufbau, Functionsweise Land Ambendung'',
Co-authored by H. Klaus and G. Heine.
bH, 1981. The output per unit volume of a unipolar step motor is smaller than that of a bipolar step motor, but because the cost of the motor control circuit is lower, unipolar step motors are especially suitable for low-output step motors. structure is often used.

When using a step motor as a servo motor,
The advantage is that, in many cases, relays are no longer necessary, since appropriate control allows for precisely reproducible settings. The limits of reproducible settings are defined by the mechanical load and the step frequency. If either or both the mechanical load and the step frequency become too high, steps will be lost, which is unacceptable for many control technology applications.

Attempts have therefore been made to use very expensive control circuits to ensure a precise course of the magnetizing current in the windings of the stepping motor.

The problem is that high movement occurs when the current suddenly increases.
These are the time constant of the coil that requires the σ operating voltage, and the high voltage due to self-induction and mutual induction that occurs during the switching process. For example, in a circuit arrangement of the type mentioned at the outset, the energy remaining in the coil when it is turned off is dissipated by a zener diode.

For the reasons mentioned above, attempts are often made to obtain as sinusoidal a course of the magnetizing current as possible. However, conventional circuits for this purpose are expensive.

For example, German Published Patent Application No. 29 of the form mentioned at the beginning.
The circuit known from No. 44355 is apparently similar to the circuit according to the invention described below. This known circuit essentially comprises a comparator, a controlled current source with a flip-flop and an output transistor. A single measuring resistor is used in the common emitter circuit of the transistor switch that switches the magnetizing current as an output switch. The current source operates according to the descending control principle. The diode in the collector circuit of the output run sister is a unidirectional diode (Free
lanqdiode) is used.

The two transistor switches, in contrast to the circuit arrangement of the invention, are not used to control the current in the phase windings. The transistor switch conducts in response to the selected step and is not reversed for the duration of one step. Therefore, the final stage of the circuit becomes extremely expensive.

Control is performed in a pseudo-analog manner via weighted resistors. Additionally, digital circuits are used to switch the direction of the current. Furthermore, the energy stored in the winding must be dissipated by the inherent limiter.

[Problem that the invention seeks to solve]

The object of the invention is to improve a circuit arrangement of the type mentioned at the outset so as to make it possible to realize a predetermined curve-shaped magnetizing current, in particular a sinusoidal magnetizing current, in good approximation and at low cost. The purpose is to reduce output loss as much as possible.

[Means for solving problems]

The object is to provide a circuit arrangement of the type mentioned at the outset, in which, according to the invention, each half-winding-switch series circuit has a current sensor, in particular a series resistor, and each of the outputs of the current sensor has a comparator. The output of the comparator is connected to one of the two inputs of the control signal, to which the reference signal is supplied, and the output of the comparator is connected to one of the two inputs of the This is achieved by being connected to a control input.

According to the invention, the magnetizing current is connected to a preset reference signal,
In particular, it is possible to control a unipolar step motor so that it follows a sinusoidal reference signal to a good approximation. The cost of the circuit is very low.

Particularly in the case of high switching frequencies, the first half-winding - the first controlled switch and the second half-winding -
In parallel with the parallel circuit of the two series circuits of the second controlled switch, connect a capacitor to this capacitor via a diode.
(Dk4tBE Kenreisha 8) Revenue and expenditure will be significantly improved.

The series resistor can be very easily connected to the input of the comparator by allowing a voltage proportional to the winding current applied to the series resistor to be supplied to the input of the comparator via a decoupling or voltage dividing resistor. be combined.

This reference signal is particularly preferably supplied to the input of the comparator via a decoupling circuit or a voltage dividing circuit.

The dynamic switching hysteresis of the comparator can be determined most simply by an RC circuit inserted in its feedback loop.

In order to protect the final stage of the circuit arrangement from disturbances due to overvoltage, which can occur, for example, due to disconnection of conductors, the terminals of the stepper motor winding on the side of the switch to be controlled are connected to a reference voltage, preferably consisting of a zener diode and a measuring resistor. It is desirable to connect the source to the series ground circuit through a diode. In that case, the measuring signal of the measuring resistor is fed to one input of the comparator, the reference signal is fed to the other input, and the output signal of the comparator is fed to the blocking input of the control circuit of the final switch. Supplied as a blocking signal. With this circuit
If so, a highly reliable blocking effect can be obtained at the final stage of the circuit at a low circuit cost.

According to a preferred embodiment of the invention, a second comparator is provided, one input of this comparator (non-inverting input)
is supplied with the output voltage of the first comparator, and its non-inverting input is grounded through a series circuit of a resistor and a capacitor, and is connected to the operating voltage via a resistor. A reference signal is supplied to the other input section (inverting input section) of the comparator, and the output voltage of the first comparator and the output voltage of the second comparator are led to an OR circuit. The output signal is routed to the control circuit as a blocking signal. The use of the second comparator makes it possible to introduce relatively long time constants for the reduction of the blocking signal.

The time constant of the first comparator can be easily realized by inserting an RC series circuit into the feedback loop of the first comparator.

Making the time constant of the resistor and capacitor connected to the non-inverting input part of the second comparator and the operating voltage larger than the time constant of the first comparator contributes to improved safety. .

To enable rapid discharging and slow charging of the capacitor, which together define the time constant of the second comparator, the value of the resistance of the series circuit at the non-inverting input of the second comparator is It is desirable that the resistance be small compared to the value of the resistance of the non-inverting input connected to the operating voltage.

To lengthen the circuit end stage in case the operating voltage is too low, the reference voltage of the first comparator is formed by a voltage divider, which can be connected to ground or via a zener diode. a voltage divider connected to the operating voltage, the zener diode forming a reference voltage for the second comparator;
and a resistor connected to the non-inverting input of this second comparator.

Next, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

〔Example〕

In Figure 1, both half-windings L+, Lm of one phase of a unipolar stench motor are connected to one pole of the stench motor's operating voltage at the midpoint of all their common windings. has been done.

The half-windings, , t, and z are strongly magnetically coupled to each other in a step motor of ordinary construction.

Each half-winding is connected to ground or to the second pole of the operating voltage via a controlled switch St, Sz and a resistor Rl, Rz, respectively.

Resistors R+, Rz are used as current sensors. The voltage drop occurring across these resistors is proportional to the currents 1, 2 passing through the half-windings, , L,. The differential voltage Δn generated between the two non-grounded points of the resistors R1 and R2 is expressed by Δn=R(1++12)=R·IN if R+=Rz=R. Here 17 is the magnetizing current passing through the field coil of the motor.

The differential voltage Δn is connected to two decoupling resistors R:+ at both inputs to a comparator with a resistor R5 in the feedback loop.
, R<. output on the comparator) "Belief%"!, -'jiO) system?i[11 a Fl-'
) ': l 4-/ f S + (') system? It is led directly to the i11 input and to the corresponding input of the second switch s2 via an inverter INV. One input to the comparator has a direct current I for setting the operating point. is the power supply Q. The other input is the current Is, which is the reference current that the magnetizing current should ultimately follow, from the current RQs. This reference current generally consists of a direct current part and an alternating current signal, preferably sinusoidal, superimposed on this direct current part.

In FIG. 2, in which the same parts as in FIG. There is. The positive supply voltage +UM is supplied via the diode D1, the capacitor C1 follows the diode D1 and the half-winding L1-switch S1-
The resistor R1 and the half-winding L2 are connected in parallel with the parallel circuit of each series branch of the switch S, resistor R2. Further, according to this embodiment, unidirectional diodes Dz, D11 are connected in parallel with the switches S, , S2. These diodes can be used for example with MOSFET type outputs.
It is already included in the n-transistor and is not treated as a special switching element in this case.

The inverting element in the control part of the controlled switch could of course be omitted if complementary semiconductor components were used. One capacitor 03, C4 is connected from the input to the comparator towards ground. Resistor R3 - capacitor C3 and resistor R4 - forming an RC circuit
Capacitor-04 is used to suppress disturbance voltages generated by the switching process. The feedback loop to the comparator is connected to a resistor R6 and a capacitor C9 forming an RC series circuit for defining the dynamic switching hysteresis.

The inputs to the comparator are connected to a resistor R6 and a resistor R? in order to fix the potential according to the DC voltage at these inputs. , Re
is connected to voltage U via. The voltage divider (resistors Rh, R3+R2 and R8+R1, R1+Rt) is
Define the operating point. The AC voltage reference signal U, is the resistance R,
+ R, to the inverting input of the comparator, in which case it is in principle of no importance which of the two inputs the reference signal is led to. Moreover, this connection may be made through a capacitor or a transformer, for example, in addition to the resistor circuit.

The operation of the circuit according to the invention will be explained according to the diagram in FIG. FIG. 3 shows the half avAL + -switch Sl-
Resistor R2 and half winding L2 - switch S2 - 2 of resistor R2
Current flowing in each of the two series shunts 1. ．． 12 and the actual magnetizing current of the field winding (reference signal U,
(indicated by a broken line) and the transition of the voltage Uc of the capacitor 01 are illustrated. The comparator receives a reference signal U as shown.

Correspondingly, in this example it is switched around a sinusoidally time-varying operating point. Half volume 61 L,, L2
The current flowing through it also changes periodically, and the actual magnetizing current Iy changes around the curve given by the reference voltage No. 1 U. The switching frequency is defined not only by the ratio U, /L, but also by the RC circuit (resistor R9 and capacitor Cz) that fixes the dynamic switching hysteresis in the comparator.

As mentioned above, along with capacitor 01, diode D
, it becomes possible to utilize the energy accumulated in the half winding 3, Lx after the cutoff. The capacitor peak voltage U, c is approximately expressed by the formula C4...Forward voltage R5 of the diode D, Dz...
- Ohm resistance L of field winding...36 Inductance of winding tag-πJ Ding Ding...Given by reversal time.

When a negative current flows through one half-winding or R2, the capacitor C is charged from this half-winding, and the diode D de-energizes the supply voltage U. This causes the voltage to rise to an excessive value, as shown in FIG. 3, and in the next switching cycle, the current in the switched half-winding increases rapidly. A precondition for this mode of operation to occur is a good magnetic coupling of the two half-windings L+, Lz.

The circuit diagram in FIG. 4 shows the final stage circuit configuration of the steering knob motor to which the present invention is applied. The illustrated circuit is designed to control two phases of each two half-windings of a two-phase unipolar stepper motor with sinusoidal waves having a phase shift of 90'. However, most of the circuit for exciting the second phase is omitted to simplify the illustration since the circuit configurations for both phases are completely symmetrical. This circuit will be briefly explained below.

The core parts of this circuit correspond to the circuit of FIG. 2 and are therefore designated by the same reference numerals as the circuit elements of FIG. Two MOSFET transistors are used for the switches Sl and Sz, which include in their construction the unidirectional diodes D2 and D3 shown in FIG. The control of the sui-nochi S2, Sl is carried out via inverters INVI, INV3 (1) respectively, these inverters are used to form normals, the output signals of which are connected to the transistors T, , T, and T3, T4. It is supplied via resistors RIS and Rho to a complementary driver stage consisting of resistors R3 and R18 and R2 and Ro. The function of inverter NV in FIG. 1.2 is appropriate for the inverter INV2. The signal is supplied to the gate of the MOSFET run sister (switch S1, Sz) via resistors R17 and R2□. Setting or limiting the switching current can be done using resistors RIS and Rit.
Alternatively, this can be done by selecting corresponding resistance values of R2° and R2□. The reference potential of the first stage of the driver is set by MOSFET transistors (switches S, S
1), to which the blocking capacitors C0 and C7 are also connected.

In order to avoid redundant switching of switches S, ,S,, the on-operation is delayed through an RC circuit (resistor RI4 and capacitor 〇, or resistor R1, and capacitor C,), and a sufficiently long dead time is obtained. make sure you get it. The diodes D4 and D5 cause a difference in time constants when charging and discharging the capacitors C5 and Cb.

The reference signal is preset by a microprocessor (not shown).
The microprocessor sets the operating point of the inverting input to the comparator via binary weighted resistors R'9, R1°, RI2. The 16 possible values provide approximate analog control with the desired curve shape.

A small capacitor C in the feedback loop to the comparator? The use of this capacitor 07 is appropriate, as it ensures a rapid rise in voltage, keeping in mind the undesirable human capacitance in the comparator. Resistor RZ& is used to set the operating point of the non-inverting input to the comparator. C1□ is a filter capacitor.

A series circuit of resistor RZ4-capacitor IO and resistor RZS-capacitor 〇11 in parallel with the half-windings Lz, L+ is used to cancel overshoot peaks during the off-operation.

In the circuit consisting of transistor T3, zener diode D8, capacitor C11 and resistors R2ff, R28, Rzq, transistor T is cut off as long as the operating voltage is below a predetermined value. in this case,
Since the switches St, Sz are cut off by the diodes DI, , D7, the circuit will not operate below the minimum operating voltage.

FIG. 5 illustrates the principle of the circuit arrangement according to the invention with a special protection circuit for the final stage. One phase semi-SQL L2 of the step motor is controlled by one controlled switch S+, Sz (e.g. field effect transistor)
is connected to the motor supply voltage +Ub. The switches Sl and SZ are controlled via control circuits AI and A2 corresponding to the control circuits detailed above. Reference signal U
S L I, U□2 can be supplied to the control circuits A I, A z via, for example, a microprocessor (not shown).

j Half windings Ll, Lm (step motor windings) connected to switches S+, Sz (final stage switch)
The terminals of are each connected to a diode D9 in a series circuit of a zener diode DI+ (URI) and a measuring resistor RM, which are either grounded or connected to the other pole of the motor supply voltage.
,D. connected via.

Measuring signal U generated at measuring resistor R7 with respect to earth potential.

is applied to the comparator at input 3 (inverted input for the selected voltage polarity). The other input (non-inverting input) of the comparator is supplied with a reference voltage UR□. This reference voltage is, for example, the operating voltage U! 4 can be easily output from + via a voltage divider. The output signal of 3 to the comparator is connected to the blocking inputs E, , E2 of the control circuit AI, A2.
is supplied as the blocking signal USP.

Next, the operation of the circuit shown in FIG. 5 will be explained.

During normal operation, voltages that are not dangerous to the switches S, , St are developed in the half-windings, , L2.

Zener diode D11 is characterized so that it is blocked when this voltage is applied.

However, abnormal operating conditions such as half-windings L1 and L2 breaking can cause overvoltage, which causes
Switches SI and S2 may be disturbed.

When this overvoltage occurs in one of the switches, S, , S, the zener diode, D, will cause the diodes, D9, DI. The voltage value at the inverting input of the comparator 3 rises because a voltage drop (measuring signal UP) occurs across the measuring resistor R, which conducts through one of the measuring resistors. When the voltage value at this inverting input exceeds the reference voltage Ul+2 at the non-inverting input, the output voltage of comparator 3 changes abruptly. This output voltage is supplied as a blocking signal to the blocking inputs E + , E z of the control circuits A, , A2, so that the switches Sr and St are blocked.

In the principle circuit diagram explained above, in order to simplify the illustration, only circuit elements important to the present invention are illustrated, and only half of the control circuit of the two-phase unipolar step motor is illustrated. ing. Switch Sl
, St can be maintained for a sufficiently long period of time by connecting a known time-regulated RC circuit to the signal path of the blocking voltage, or by inserting a flip-flop controllable by an external signal.

An actual circuit specifically designed to hold this blocked state for a sufficiently long period of time is detailed in FIG.

The circuit shown in Figure 6, excluding the protection circuit, consists of two half-windings each of a two-phase unipolar step motor.
It basically corresponds to the circuit shown in FIG. 4, which was designed to control the phase by a sine wave with a phase shift of 90'. The illustration of the circuit portion for controlling the second phase is also omitted to simplify the drawing since the circuit configurations for the two phases are completely symmetrical.

The controlled switches S+ and Sz include two MOSFs.
ET) Runsister is used. motor 1
One terminal of the two half-windings L+, Lz of the phase is connected via a diode D zIlo and a choke Lzo+ to the operating voltage -1-U. The other terminal of the half-winding wire, L2, is connected to the ground GND via the switches Sz, Sz and the current sensor (resistors RZ81, R211□). Diode D z[l.

The capacitor 〇 280 placed after is used to increase the efficiency of the circuit and corresponds to capacitor C, in Fig. 2.4.

The difference signal generated at the resistors Rzs+ and Rz*z is connected to the RC circuit (resistor RZI?, C210 and resistor Rztas C
z+1) and decoupling resistors R2□8, R2□, and are led to the + input part of the comparator, and the output signal of 1 to the comparator is
Inverter INV and complementary driver one stage T2゜3
, T2゜2, to the switch S1, or to the inverter INVs and the complementary driver stage T2゜3,
They are respectively guided to switch S2 via T2°4.

The presetting of the reference signal to which the magnetizing current of the motor windings should ultimately follow is carried out, as described above, via a microprocessor (not shown), which controls the binary weighted resistors R24° to R246. Via the comparator, the operating point of the input part of! Set.

Resistors R241 to R245 are so-called pull-up resistors for reducing the load on the output section of the microprosensor. The output section SMA informs the microprosensor of the state of the final stage (on or off).

Next, the portions of the circuit shown in FIG. 6 that are related to the present invention will be explained. The voltage at the terminals of the half-turns 35tL, , Lz connected to the switches 5, , S, is the voltage of the zener diode D.
11 (voltage U□) and the measuring resistor R, in a series grounding circuit,
Isolation diode D9, DI. guided through. The conductor is connected to the second phase winding terminal (not shown) of the motor, also via a diode, in a manner not shown.

- As an example, if the motor supply voltage Ul = 12V:
The zener voltage of the zener diode D is selected to be 64V, and the resistance value R of the resistor RM is selected to be 500 mΩ.

The measuring signal Up generated at the measuring resistor RM is fed to the inverting input of the comparator via the resistor R26. This input section goes through the resistor RZsq to the operating voltage needle +UB, and through the capacitor C2□4 to the ground point.
each connected. In the comparator, is the resistor RZ&.

It receives the supply voltage through. A filter capacitor C2□3 is installed here. The non-inverting input of 3 to the comparator is connected to a voltage divider (resistor RZ63, Rzba
) are connected through. This forms the reference voltage U, □ at the non-inverting input of the comparator Kx. As an example of the characteristic value of each circuit element, Rzsq"33 is ohm, R
261・=1 to ohm, Rzas=12 to ohm, Ri
hs = 1 ohm, Uz (Dz+o) =
5.6 V, C224=4.5 nF, RZ66=1
5 ohms, CZ23 = l OOnF.

The feedback loop of 3 to the comparator includes an RC series circuit (resistor Rzbz, 22 ohms and capacitor 02□
5,470nF) is connected.

In addition, there is a resistor RZ6? of a voltage divider R2h6, R2, 7 connected to the operating voltage via a zener diode D210 from the inverting input of this comparator. is grounded as shown. Capacitor C2□7 is connected in parallel with resistor R267.

This forms the reference voltage UR2 at the inverting input. The 4 non-inverting inputs to the comparator include a resistor R26S and a zener diode D! +.

is connected to the operating voltage +tJn through the resistor R2.
It is grounded through a series circuit of b8 and capacitor C2□. The non-inverting input of 4 to the comparator is a diode D.
2°, and is connected to the output of 3 to the comparator.

There is a capacitor c in the feedback loop of 4 in the comparator.
tzb is connected.

An example of the characteristic value of each circuit element is R266” 1.2
k ohm, RZ&? = 12 k ohm, C227 =
47 nF, R245 = 56 kOhm, Rz6
g=680 ohm, C2□,=4.7μF, C2□h=
It is 41 pF.

The output signal U'SP of 3 to the comparator or the output signal U''3 of the comparator is pnp) run sister T2°,
At the base of , resistor R2□. %R2'11.

pnp) There are two resistors RZS in the collector circuit of Runsistor T2゜. , Rzsa are connected in series, of which the resistor R2,8 is connected to the capacitor 02□,
It is re-bypassed by. A resistor R26 is connected between the base and the emitter. The collector is connected to the inputs of the inverters INV, INV5 via diodes D2.2, D2.4. On the conductor,
It is similarly connected to an inverter input of a control circuit (not shown) of the second phase of the step motor. Transistor T2.9 receives at its input two signals U′81, U″
, P operates as a switching stage. A signal USF is generated at the output. An example of the characteristic values of the circuit elements used here is R,6,=R,
? . =Rzz+=33 ohms, Rzs+=6.2
k ohm, R,.

= 3.6 kOhm, C2□+ = 220 pF.

The protection circuit described above operates as follows. When an overvoltage occurs in one of the half windings L+, L2 (or one of the half windings of the unillustrated second phase of the step motor), the zener diode DI+ switches to the isolation diode D? , DIG, and a positive measuring voltage is applied to the measuring resistor R9). . , Yo9, □. E3゜A The voltage at the transfer blade increases (a voltage of about +0.5■ is generated at the non-inverting input of the comparator).

The output signal of the comparator, which had previously been at a positive voltage, is
Descending towards zero. This corresponds to the generation of the blocking signal U'SP. Since the transistor T2° is conductive, the inputs of all the inverters INV, , INVS (and the two not-shown inverters of the second circuit part) are
Approximately, the potential increases to the operating voltage +Us. As a result, all the final stage switches S,,S, are cut off.

To the comparator, after the overvoltage is removed, the output of
During the course defined by the voltage (seconds), the voltage again becomes positive.

Since overvoltages usually only occur for a short time, after the peak voltage has disappeared, all circuit stages are
・Suddenly becomes ready for operation in response to czzs'
This is undesirable for safety reasons.

For this reason, it is important to keep the blocking signal together with its circuit elements.
Delay e f ,L? , :″＞0 comparator′・”′More′
Even.

It is.

When the output signal of comparator 3 becomes zero, the non-inverting input of comparator 4 is pulled to zero potential, so the output of comparator 4 also becomes zero potential. At the same time, previously charged capacitor C2□8 is connected to resistor RZ&8 and diode D2
．． 9 and discharge.

After the overvoltage disappears, when the comparator 3 is again in its output state, the capacitor C2□8 is connected to the resistor RZ611,
It is charged again via R265. Since the value of resistor R265 is higher than the value of resistor R268, charging occurs at a slower rate than discharging until the switching dark value of 4 is again reached in the second comparator. The time constant of 4 in the comparator is approximately 260 m.
seconds, the associated charging time is approximately 600 msec. The discharge time constant during discharge is approximately 3 msec (approximately 1/3 of the reversal time of 3 in the comparator). In the second comparator, the output voltage of increases again towards the operating voltage +U8, and the transistor T2°,
is blocked. As long as the overvoltage does not occur again, the final stage of the circuit becomes operational again.

The illustrated circuit additionally includes protection against unacceptable drops in operating voltage. This will be explained in detail below.

The first comparator has resistors R257 and R257 at its inverting input.
21, (the resistance RzIlo is lower than the resistances Rzsq, RZ&+) is generated. Zener diode DZIO supplies current to voltage divider R26:l, RZ64. This voltage divider causes the comparator to fix the voltage at the non-inverting input of 3. For the characteristic values of the exemplary circuit elements, the inverting input part has the normal operating voltage +U, = 12■, 12/
(33+, L) = 0.35 v, the non-inverting input part has:
(Us −Uz )/(1442)=(12−5,6
)/13=0.5V results.

From this, when the operating voltage U, drops to, for example, 6.times., the voltage at the inverting input drops to about o,is v, and the voltage at the non-inverting input drops to about 3QmV. However, this means that the polarity of the re-input to the first comparator is inverted compared to the normal operating voltage. The voltage at the output of the comparator drops to zero and the final stage of the circuit is switched off via the transistor T2°. The second comparator 4 performs the same function as described above in connection with overvoltage shutdown. Therefore, unspecified switching of the step motor when the operating voltage drops significantly is avoided.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the principle circuit of the present invention, Fig. 2 is a circuit diagram showing a circuit for utilizing the energy stored in the half winding, and Fig. 3 is a circuit diagram according to the present invention. A diagram for explaining the main functions of the device, Figure 4, shows the unipolar
FIG. 5 is a circuit diagram showing a practical circuit according to the invention for controlling two phases of a type step motor; FIG. 6 is a wiring diagram showing the actual detailed configuration of the circuit of FIG. 5 related to the control circuit of the step motor. Description of symbols Ll, L2...half winding, S+, Sz...switch, +U14...supply voltage, K...comparator, U,...AC voltage reference signal (reference signal), ■ . ...Reference signal, R1, R, ...Resistance (series resistance).

Claims (1)

[Claims] 1) having two half-windings per phase, each half-winding of each phase being connected to the supply voltage of the stepper motor in series with a controlled switch; , further comprising a current sensor for the stepper motor current, the output signal of the current sensor being led to a comparator, the output signal of the comparator being referred to for controlling the stepper motor current. A circuit arrangement for controlling a unipolar step motor, in which each series circuit of half windings (L_1, L_2)-switches (S_1, S_2) is connected to a current sensor, in particular a series resistor (R_1, R_2). and the output of the current sensor is connected to each one of the two inputs of the comparator (K).
One of the inputs is connected to the reference signal (U
_s, I_s), and the output of the comparator K is connected to the control inputs of controlled switches (S_1, S_2) which are switched out of phase with respect to one control signal. switching device. 2) Two series circuits, namely the first half-winding (L_1) and the first
series circuit of the controlled switch (S_1) or the second half-winding (L_2) - the second controlled switch (S_2
A capacitor (C_1) is connected in parallel with a parallel circuit consisting of a series circuit of ), and the capacitor (C_1) is connected to the supply voltage (U_m) of the stepping motor via a diode (D_1). A circuit device according to claim 1. 3) A voltage proportional to the winding current applied to the series resistor is applied to the decoupling resistor or current dividing resistor (R_3, R_4
3. The circuit arrangement according to claim 1, wherein the circuit arrangement is led to the input section of the comparator (K) via the circuit (K). 4) Reference signal (U_s is a decoupling resistor or voltage dividing resistor (
4. The circuit arrangement according to claim 1, wherein the circuit arrangement is led to the input of the comparator (K) via the circuits R_5, R_6, R_7). 5) An RC circuit (R_5,
5. The circuit device according to claim 1, wherein C_2) is connected. 6) a series circuit in which the terminals of the half windings (L_1, L_2) of the step motor connected to the controlled switches (S_1, S_2) are grounded to the reference voltage source (U_R_1);
In particular, the zener diode (D_1_1) and the measuring resistor (R
Diodes (D_9, D_1_
0) and the measurement signal (
U_P) is led to one input of the comparator (K_3),
The other input of the comparator (K_3) is connected to the reference voltage (U_R_
2) is applied, and the output signal of the comparator (K_3) is applied to the control circuit (A_1, A_2) of the switch (S_1, S_2).
A blocking signal (U_s_
6. The circuit arrangement according to claim 1, wherein the circuit arrangement is provided as p). 7) A second comparator (K_4) is created and the comparator (K
_4) is supplied with the output voltage (U_s_p) of the first comparator (K_3) to one input, that is, the non-inverting input;
One input section is grounded through a series circuit of a resistor (R_2_6_8) and a capacitor (C_2_2_8), and is also connected to an operating voltage (+U) through a resistor (R_2_4_5).
_b), and the other input of the second comparator (K_4), namely the inverting input, is applied with the reference voltage (U_R_3), and the output voltage (U'_s_
p) and the output voltage (U″_s) of the second comparator (K_4)
_p) is an OR circuit (R_2_7_0, R_2_7_1
, T_2_0__9), and the output signal of the OR circuit (
U_s_p) is a control circuit (T_2_0_1, T_2_
0_2, INV_4---; T_2_0_3, T_2_
0_4, INV_5, ---) is provided with a blocking signal (U_s_p
) Claim 6 characterized in that it is derived as
The circuit device described in Section. 8) The first comparator (K_3) has a series RC circuit (R_2_6_2, R_2_2_5) in its feedback loop.
A circuit device according to claim 6 or 7, characterized in that the circuit device has: 9) The time constant of the resistor (R_2_6_5) and capacitor (C_2_2_8) connected to the reference voltage and the non-inverting input of the second comparator (K_4) is the time constant of the first comparator (K_3). 9. The circuit device according to claim 7 or 8, characterized in that the length is longer than that of the circuit device. 10) Change the value of the resistance (R_2_6_8) of the series circuit (R_2_6_8, C_2_2_8) at the non-inverting input of the second comparator (K_4) to the value of the resistor (R_2_6_5) that reaches the operating voltage at the non-inverting input. The circuit device according to any one of claims 7 to 9, characterized in that the circuit device is made smaller in comparison. 11) Reference voltage (U_R_2) of the first comparator (K_3)
) is formed by a voltage divider (R_2_6_3, R_2_6_4), which voltage divider is grounded or
The operating voltage (
+U_B) and the zener diode (D_2_1
_0) is the reference voltage (U_R
voltage divider (R_2_6_6, R_2) forming the voltage divider (R_2_6_6, R_2
_6_7) and a resistor (R_2_6_5) connected to the non-inverting input part of the second comparator (K_4).
The circuit device described in Section.