JPS62236386A - Driving circuit for stepper motor - Google Patents

Abstract

PURPOSE:To obtain a stable rotary torque of a stepper motor by raising an exciting current switching level higher than that at 2-phase exciting timing in the l-phase exciting timing of each phase of the motor. CONSTITUTION:l-2 phase exciting signals are input to transistors 9-12 of phases. The outputs of output voltage converters 30, 31 which input the output of a timing generator 27 become at current detecting reference voltage at the l-phase exciting timing higher than a current detecting reference voltage at the timing in the 2-phase exciting, and exciting currents 5-8 flow to phase windings l-4 of a stepper motor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a 1-2 phase excitation drive circuit for a stepping motor, and particularly to a 1-2 phase excitation drive circuit using the Terra-Tsuba method.

[Conventional technology]

Conventionally, a drive circuit for this type of stepping motor has been constructed as shown in FIG. In Figure 3, 1.2.3.
4 is the winding for each phase (1 is 1 phase, 2 is 2 phases.

3Fi 3 phase, 4 corresponds to 4 phase), 5.6.7.8
9, 10, 11.12 are transistors for controlling conduction and non-conduction of each phase.

13 is a 1-phase and 3-phase common transistor, 14 is a 2-phase and 4-phase common transistor, 15 is a 1-phase and 3-phase current detection resistor, 16 is a 2-phase and 4-phase current detection resistor, 17
is the reference voltage for current detection, 18 is the excitation current flowing in the 1st or 3rd phase (output of the current detection resistor 15) and the reference voltage 17 for current detection is compared, and the excitation current flowing in the 1st or 3rd phase is compared to the reference voltage. When the level is low, the common transistor 13 is made conductive.

A common transistor control circuit 19 makes the current non-conductive if it is high, and compares the excitation current (output of current detection 16) flowing in the 2 or 4 phases with the reference voltage 17 for current detection, and determines the current flow in the 2 or 4 phases. 3. A common transistor control circuit that makes the common transistor 14 conductive when the excitation current is lower than the reference value and non-conductive when it is higher than the reference value; 20.
21 is an excitation current supply power source and a ground.

Figure 4 shows the operation time chart and waveform diagram of Figure 3. Control transistors 9 and 1 for each phase
0. The 1-2 phase excitation signal (1
corresponds to the 1st phase, 2 to the 2nd phase, 3 to the 3rd phase, and 4 to the 4th phase, and when the transistor is turned on at the H (high) level and off when it is at the L (low) level, each phase of the motor is input. The windings have exciting currents of 5, 6, 7.8 (5 is 1 phase, 6 is 2 phase, 7 is 3 phase, 8
(corresponds to 4 phases) flows, and the rotational torque generated is shown in Figure 4.9.
It looked like this (conceptual diagram).

[Problem that the invention seeks to solve]

In the above-mentioned conventional stepping motor drive circuit, the 1-2 phase excitation drive circuit is based on the chip type.

Rotational torque generated at the timing of one-phase excitation (first,
41D90A-BoCm) d! 2aliE[c7]
/-(i Rotational torque generated at y/ (a@ in Fig. 4, 9)
There is a drawback that it is smaller than the beC section) and stable rotational torque cannot be obtained.

[Means for solving problems]

The stepping motor drive circuit of the present invention is a stepping motor drive circuit using 1-2 phase excitation drive using the Tetsutsuba method, in which the excitation current switching level is set to 2 at the timing of 1-phase excitation of each phase of the stepping motor.
It is configured to include means for increasing the switching level at the timing of phase excitation.

〔Example〕

Next, one aspect of the present invention will be explained with reference to the first page.

FIG. VI1 is a circuit diagram of an embodiment of the present invention. 1゜2
．． 3.4 is the winding of each phase of the motor (1 is 1 phase, 2 is 2 phases,
3 corresponds to 3 phases, 4 corresponds to 4 phases), 5, 6, 7° 8 is the exciting current flowing in each phase, 9, 10, 11.12 is the continuity of each phase,
Transistor for non-conducting control.

13 is a 1-phase and 3-phase common transistor, 14 is a 2-phase and 4-phase common transistor, 15 is a 1-phase and 3-phase current detection resistor, 16 is a 2-phase and 4-phase current detection resistor, 27
is a timing generation circuit that generates the timing when each phase becomes one phase from the input signal of each phase.

28 is the output of the timing generation circuit 27, which is either 1 phase or 3 phase.
29 is the output of the timing generation circuit 27 and is a timing signal at which 2 or 4 phases become 1-phase excitation (1-phase excitation a at high level); 30 is an output voltage switching circuit whose output voltage level is switched in response to the timing signal 28, 31 is an output voltage switching circuit whose output voltage level is switched in response to the timing signal 29, and 32 is the output of the output voltage switching circuit 30, which is one phase. Or 2-phase current detection reference voltage %33 is the output voltage switching circuit 3
Reference voltage for current detection for 2 or 4 phases with 1 output, 18
is the exciting current flowing in 1 phase or 3 phases (current detection resistor 1
5) and the current detection reference voltage 32, and depending on whether it is larger or smaller, the common transistor 1 of the 1st phase and 3rd phase
3 is non-conductive.

Common transistor control circuit for conduction.

19 compares the excitation current (output of the current detection resistor 16) flowing in the 2-phase or 4-phase with the current detection reference voltage 33,
A common transistor control circuit makes the two-phase and four-phase common transistors 14 non-conductive and conductive depending on whether they are large or small, 20 is a power supply, and 21 is a ground, respectively.

FIG. 2 is a diagram showing the operation time chart and operation waveforms of FIG. 1. Transistors for each phase 9゜10.11,
12, 1-2 phase excitation signals 51, 52, 5 shown in FIG.
3,54 (1 is 1 phase, 2 is 2 phases.

3 corresponds to 3 phases, 4 corresponds to 4 phases, the transistor is conductive at the 'H' level, and the transistor is non-conductive at the 'L' level), the timing of the timing generation circuit 17 shown in FIG. 1 is input. The signal 28゜29 has a waveform as shown in Fig. 2 ('H'' level is the timing of one-phase excitation), and the current detection reference voltage 32゜330 waveform, which is the output of the output voltage switching circuit 30, 31, has the second waveform. The waveform is as shown in the figure (the reference voltage for current detection at the timing of one-phase excitation is higher than the reference voltage for current detection at the timing of two-phase excitation), and the excitation current 5, 6
, 7.8 (corresponds to 1 phase, 5.2 phase, 6. 3 phase, 7 to 4 phase, 8 to 4 phase), and the rotational torque generated by flow 1 is shown in the waveform 34 (in Figure 2).
It will look like this (conceptual diagram).

By appropriately setting the ratio of the magnitude of the current detection reference voltages 32 and 33 at the timing of one-phase excitation and the timing of two-phase excitation, the rotational torque generated at the timing of one-phase excitation of the stepping motor (Fig. Waveform 34 shown in
The difference between the rotational torque generated at the timing of two-phase excitation (waveforms 340a, b, and c shown in FIG. 2) can be reduced or eliminated.

〔Effect of the invention〕

As explained above, the present invention is based on the 1-2 method using the chi-1 method.
In the stepping Tanabata drive circuit using phase excitation,
It has a circuit that makes the switching level of the excitation current higher at the timing of 1-phase excitation of each phase than the switching level at the timing of 2-phase excitation, and the ratio of the switching level between the timing of 1-phase excitation and the timing of 2-phase excitation is Proper installation makes it possible to reduce or eliminate the difference between the rotational torque generated at the timing of one-phase excitation and the rotational torque generated at the timing of two-phase excitation, resulting in the effect of obtaining stable rotational torque.

[Brief explanation of drawings]

1 and 2 are a circuit diagram of an embodiment of the present invention and an operational configuration diagram of FIG. 1, respectively, FIG. 2 is a time chart, and FIGS. 3 and 4 are a diagram of a conventional stepping motor drive circuit. They are a circuit diagram and a time chart. 1, 2. 3. 4... Winding of each phase, 5.
6. 7゜8...Exciting current flowing through each phase, 9
．． 10. 11゜12... Each phase transistor, 15.16... Current detection resistor, 17...
...Reference voltage for current detection S 18°19...
comparison circuit and common transistor control circuit,
20...Power supply, 21...Ground. 27... Timing generation circuit S 2B, 29.
...Timing signal, 30.31...Output voltage switching circuit. Agent Patent Attorney Susumu Uchihara Minnie 5 1st Kaya 2

Claims (1)

[Claims] A driving circuit for a stepping motor using 1-2 phase excitation drive using a chopper method, including means for making the switching level of the excitation current higher at the timing of one-phase excitation of each phase of the stepping motor than the switching level at the timing of Z-phase excitation. This is a stepping motor drive circuit characterized by the following.