JPH01291698A - Pulse motor driving circuit - Google Patents

Abstract

PURPOSE:To drive a pulse motor at an angle smaller than an inherent step angle of the pulse motor by changing the ratio between energization time and interruption time of the current supplied to a winding at a specific period. CONSTITUTION:A micro-computer 1 outputs signals to each of an output port circuit 3, a first timer circuit 4 and a second timer circuit 5 through a system bus 2. An output end of the first timer circuit 4 is connected to the other input end of a two-input AND circuit 6, but, at the same time, it is connected to one input end of a two-input AND circuit 10. An output end of the second timer circuit 5 is connected to the other input end of a two-input AND circuit 8, but, at the same time, it is connected to one input end of a two-input AND circuit 11. By controlling those timer circuits 4 and 5, the energization time and interruption time of the current are changed at a specific period.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a pulse motor drive circuit used in printers, facsimile machines, etc., and more particularly to a pulse motor drive circuit that drives a pulse motor in microsteps.

(B) Prior Art Conventional pulse motor drive circuits, particularly drive circuits for microstep drive, which controls drive at angles smaller than the step angle unique to pulse motors, use pulse motors as shown in FIG. A circuit is known that executes a method of selecting and switching current values flowing through each phase of a motor. In FIG. 6, this analog pulse smoke drive circuit is
For example, by dividing 5V of DC using the resistor circuit 30, the voltage v
+, Vt+ V31 Va, and these voltages V
l+VI V3. One of Va is selected by an analog data selector 31 operated by a selection signal from a CPU (not shown), and is output to a switching motor driver 32. The switching motor driver 32 includes a comparator 33, a switching transistor 34, and a current detection resistor 35.
The voltage vi outputted from the analog data selector 31 is input to the input voltage of 3, and the voltage vj from the current detection resistor 35 is input to the input voltage of 3. The comparator 33 controls the switching transistor 34 so that the voltage vi and the voltage vj are equal. □ Turn on and off so that each phase winding A,
Controls the currents flowing through τ, B, and H. In other words, this current control controls the currents flowing through the windings A, -λ'', B, and T3 of each phase so that the composite torque vector T moves at a small angle on the circumference.

(c) Problems to be solved by the invention However, in the above pulse motor drive circuit, in order to increase the step resolution, it is necessary to use a high-precision resistor in the resistor circuit, which is an analog circuit, which reduces accuracy and cost. It was disadvantageous in that respect.

In other words, step resolution is affected by high-precision resistors, and increasing precision increases manufacturing costs accordingly.

This invention has been made in consideration of the above circumstances, and therefore aims to provide a pulse motor drive circuit that can improve accuracy without increasing cost.

(d) Means for Solving the Problems Thus, according to the present invention, there is provided a winding selection means for selecting a winding to be excited of a pulse motor, and a current to be supplied to the winding selected by the winding selection means. A current supply means that supplies current to the surface winding by changing the ratio of the energization time and the de-energization time at a predetermined cycle, and the pulse motor can be operated at an angle smaller than the step angle specific to the pulse motor. A pulse motor drive circuit is provided, which is characterized in that it is capable of driving a pulse motor.

(e) The active winding selection means selects the non-excited winding of the pulse motor to be driven. A current is supplied to the selected winding from the current supply means. The current is changed by the current supply means at a predetermined cycle of the energization time and the power-off time. As a result, the pulse motor is driven in microsteps at an angle smaller than the step angle specific to the pulse motor.

(F) EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following examples.

The circuit shown in FIG. 1 is of a two-phase excitation force type for a two-phase pulse motor. Signals are output to the timer circuit 4 and the second timer circuit 5, respectively.

The output port 3a of the output port circuit 3 that outputs ○ to the excitation phase signal is connected to one input end of the two-man power AND circuit 6 and NOT
and the input terminals of the circuit 7, respectively. Further, the output port 3b of the output port circuit 3 that outputs the excitation phase signal B0 is connected to one input end of the two-man power AND circuit 8 and the input end of the NOT circuit 9, respectively.

The output terminal of the first timer circuit 4 is a two-man power A N D circuit 6.
When it is connected to the other input terminal of , it is connected to one input terminal of the two-man power AND circuit 10 . The output end of the second timer circuit 5 is connected to the other input end of the two-man power AND circuit 8, and then to one input end of the two-man power AND circuit 11.

The other input end of the two-man power AND circuit 10 is connected to the output end of the NOT circuit 7, and the other input end of the two-man power AND circuit 11711 is connected to the output end of the NOT circuit 9. Each two-person AND circuit 6, 8.10,! The output terminal of I is connected to the current control circuit 20. The current control circuit 20 may have a circuit configuration known in the art, for example, is configured with switching transistors provided corresponding to each winding, and is configured to control the motor output from a motor drive power source having the necessary current capacity. The drive current is ANDed by two people
The motor winding current control signals outputted from the circuits 6, 8, 10, and 11 are supplied to the windings to be excited. 21 is a driven pulse motor.

Microcomputer 1, output port circuit 3.2 Human power A
ND circuit 6.8.10.1+ and NOT circuit 7.
9 constitutes a winding selection means 100. Also, a microcomputer 1 and first and second timer circuits 4.
5 and the current control circuit 20 constitute a current supply means 200.

The first and second timer circuits 4.5 each include a latch circuit 1 connected to the system bus 2, as shown in FIG.
2 and the output terminal 12a of the latch circuit 12,! 2b, 12
Input terminal +3 connected corresponding to c and 12d, respectively
a, 13b, 13c.

13d, a second binary counter 14 that controls the operation of the first binary counter 13, and a ripple carrier terminal (hereinafter referred to as RCO terminal) 13f of the first binary counter 13 has an input terminal thereof. A NOT circuit I5 whose output terminal is connected to the enable E input terminal 13g of the first binary counter 13, and an RCO of the second binary counter 14.
A NOT circuit 16 whose input terminal is connected to the terminal 14a
, the signal output from the NOT circuit 16 and the load input terminal +43j of the second binary counter 14 are input
The timer circuit may be a timer circuit composed of a two-manpower A N D circuit 7 whose output terminal is connected to the load input terminal 13j of the first binary counter I3. .

The first and second binary counters 13,14 are preferably 4-bit binary counters such as 7JLSI61, for example. Second binary counter! 4 input terminal +
4 a, I 4 b, I 4 c, (4d
are connected to ground 18, respectively. A clock signal CLOCK is input to the clock input terminals 13h and 14h of the first and second binary counters 13.14. A gate signal GAT is applied to the enable T input terminal 13 of the second [and second binary counter 13, 14k].
E is human-powered.

Enable E input terminal 14 of second binary counter 14
A power supply voltage of +5V is applied to g.

Next, the operation of this embodiment will be explained with reference to FIGS. 3 and 4.

The output boat circuit 3 connects to the CPLI+ via the system bus 2.
The signals input from each output port 3a
, 3b, as shown in FIG.
”, and the excitation phase signal A becomes “High” at an angle of π/2.The excitation phase signal A and the excitation phase signal BO are respectively output.

Bo chives and each two-man AND circuit 6°8.
10.11 is the first pulse signal D1 and the second pulse signal D2 output from the first and second timer circuits 4.5.
is selectively output to the current control circuit 20 as the motor winding current fil[I signal.

The first and second pulse signals DI and D2 respectively output by the first and second timer circuits 4.5 are (DI) = 1(
+/, /T)+s inθ1(D2)=1 (1/
J2) ・cosθ1CD I) '+ (D2
) = 1. Therefore, as shown in Fig. 4, the magnitude of the resultant torque vector is a constant value independent of the step angle. Torque vector TVI in Fig. 4 is in phase PI in FIG. 3, and similarly torque vectors TV2, 3
．． 4.5 are respectively phase P2. P3. P4. This is in P5.

To explain the operation when the first and second timer circuits 4.5 are the timer circuits shown in FIG.
The first and second pulse signals D1. Data determining the on/off ratio of D2 is input to the latch circuit I2. For this data, the load signal LOAD is Low''
and the RCO terminal 14f of the second binary counter 14
Loaded every time a carry signal is output from . Next, by setting the gate signal GATE input to the respective enable T input terminals 13 and 14k to "High," the respective binary counters 13 and 14 receive the clock signals input to the respective clock input terminals 13h and +4h. Start counting CLOCK.The second binary counter 4 operates as a hexadecimal counter and counts 1
A load signal is first supplied to the inary counter 13 at a period of 6xt (however, the rainbow is the period of the clock signal CLOCK). Assuming that the value of the loaded data is V, the first binary counter 13 receives a signal after a signal is input to the load input terminal +3j and after a time period such that W=(16-v)Xt, as shown in FIG. N because it outputs a carry signal.

T circuit! The output signal from the timer circuit 5 is a signal having a period of 16×t and a duty cycle with an on time of W/16t.

Therefore, by changing the value of the data loaded into the first binary counter 13, the on/off duty cycles of the signals, that is, the first and second pulse signals DI and D2, can be continuously changed. Note that the data to be loaded is from the microcomputer (CDI).
Either calculate a data group that satisfies the relationship '+ (I) 1)' = 1, or store < in the ROM as data in advance and output it to the latch circuit 3 at the required timing. All you have to do is program it. The data loading timing is the I/n period of the switching timing of the excitation phase signals Ao and Bo when realizing a microstep of Ω/n, assuming that the unique step angle of the driven pulse motor is Ω. In FIG. 3, n=4.

(G) Effects of the Invention According to the present invention, a pulse motor drive circuit can be obtained that can improve smooth operation and positioning resolution in microstep drive without using a high-precision resistor.

[Brief Description of the Drawings] Fig. 1 is an electric circuit diagram showing the configuration of an embodiment of the present invention, and Fig. 2 is an electrical circuit diagram showing the configuration of an embodiment of the present invention. and an electric circuit diagram showing the configuration of the second timer circuit, FIG. 3 shows the relationship between the two excitation signals,
A time chart showing the excitation sequence and the relationship between two pulse signals, FIG. 4 is a torque vector diagram of the pulse motor driven in the embodiment, and FIG. FIG. 6 is a time chart showing the relationship with the carry signal output from the two-binary counter, and FIG. 6 is an electric circuit diagram showing the configuration of a conventional example. ■・・・・・・Microcomputer, 3・・・・・・
Output Boat, 6.8.10. I+...2 manual AND circuit, 7
．． 9...N07 circuit, 4...1st timer circuit, 5...2nd timer circuit, 20...
- Current supply circuit, 2I... Pulse motor, 100... Winding selection means, 200... Current supply means. Sash 1 Zutsutsu 4 Diagram 8 value 6 Diagram

Claims (1)

[Claims] 1. A winding selection means for selecting a winding to be excited of the pulse motor, and a ratio between an energization time and a de-energization time of a current supplied to the winding selected by the winding selection means at a predetermined period. and current supply means for supplying current to the windings, the pulse motor drive circuit being capable of driving the pulse motor at an angle smaller than a step angle specific to the pulse motor.