JPS59122399A - Drive control circuit for stepping motor - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy by correcting the target stopping position of a magnetic head in response to the different amount when the target stopping position is different from a theoretical position. CONSTITUTION:An error pulse signal EP produced when a stopping position is improper, an output of a monostable circuit 2 and an output signal by a delay circuit 4b are generated. A stepping motor starts moving by a signal G and a signal H corresponding to the first pulse F1 of a signal F. The exciting phase of a stepping motor is returned to the original state by the two pulses F2, and the signal H. In this manner, the stepping motor rotatably drives in a slight period during when rotating in one step and drives to the target stopping position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a stepping motor drive control circuit used, for example, in a flexible magnetic disk device.

[Technical background of the invention and its problems]

In general, flexible magnetic disc devices (hereinafter simply ()
In this disk device, etc., a stepping motor is used to control the positioning of the magnetic head. In positioning control using a stepping motor, the magnetic head is
It is easy to control as it can move one track with a pulse, and high positioning accuracy can be obtained.

However, in reality, even if the performance of the stepping motor is the same, the positioning accuracy is not constant due to changes in the friction system of the mechanism related to positioning control.

Moreover, there are usually variations in performance of stepping motors, and it is difficult to obtain the same performance.

Therefore, for example, in a disk device, even if the same medium is used and the magnetic head seeks on the same track, it may not be located on the same circle on the medium. In some cases, parts constituting the disk device expand and contract due to temperature, humidity, etc., which may have an adverse effect on the positioning control.

That is, conventionally, it has been extremely difficult to control the positioning of a magnetic head using a stepping motor with high accuracy in a disk device or the like.

[Purpose of the invention]

This invention was made in view of the above circumstances, and its purpose is to control the positioning of the magnetic head of a disk device (herein, when the intended stop position of the magnetic head is different from the theoretical position, An object of the present invention is to provide a stamping motion thought and movement control circuit that can improve positioning accuracy by correcting the positioning accuracy.

[Summary of the invention]

The present invention controls the excitation phase of the stepping motor based on a step pulse corresponding to positioning and a direction indicating signal indicating the direction of rotational drive. After a predetermined positioning operation, when the step pulse generation stops, a pulse signal having a predetermined pulse width is output from a pulse generating means such as a monostable based on the positioning error pulse signal fδ. Based on this pulse signal, the logic gate circuit outputs a drive pulse signal corresponding to a step pulse and a signal corresponding to a direction instruction signal to control the excitation phase of the stepping motor again. Thereby, in the first positioning operation, the corrective positioning operation is performed in response to the positioning error pulse signal that is output when the target stop position is different from the theoretical position.

[Embodiments of the invention]

Embodiment C of the present invention will be described below with reference to the drawings. FIG. 1 shows a stepping motor 1u according to the present invention.
1 is a first monostable multi-pie break (hereinafter referred to as monostable circuit), which responds to the input of the step pulse SP (that is, after a certain period of time after the input stops) 2) Output a pulse signal A with a predetermined pulse width and its inverted signal B, respectively. The second monostable circuit 2 operates for a period corresponding to the input of the pulse signal B, and outputs the pulse signal C in synchronization with the input of the positioning error pulse signal (referred to as the error pulse signal in the lower half of μ). Output. This pulse signal C is
The signal is applied to one input terminal of an exclusive logic circuit (hereinafter referred to as an EX-OR circuit) 3a, and is applied to one input terminal of an EX-OR circuit 3b via a first delay circuit (DLl) 4a. The other input terminal of the EX OR circuit 3a is
A pulse signal C is applied via a second delay circuit (DL2) Jb. The other input terminal of the EX OR circuit 3b is
A direction signal indicating the direction of rotation of the stepping motor is provided. The EX OR circuit 3C has one input terminal supplied with the step pulse SP, and the other input terminal supplied with the output signal F of the EX OR circuit 3a. EX
Both OR circuits 3b and 3c output signals H and H, respectively.
G is output to the excitation division circuit 5 of the stepping motor.

The excitation division circuit 5 includes EX-OR circuits 6a, 6b and D-type flip-flops (IJ, hereinafter simply referred to as flip-flops) 7a, 7b to which output signals I, J of the EX-OR circuits 6a, 6b are applied, respectively. We are prepared. The EX-OR circuit 6a has one input terminal supplied with the output signal H of the EX-OR circuit 3b, and the other input terminal supplied with the inverted output signal of the flip-flop 7b.

Further, the EX OR circuit 6b has one input terminal supplied with the above output signal H, and the other input terminal supplied with each clock terminal C.
The output signal G of the EX-OR circuit 3C is commonly applied to LK. Flip-flops 7a and 7b output each normal output signal, M and each inverted output signal, and N to a driver circuit 8, respectively. The driver circuit 8 outputs a peak to each output signal from the flip-flops 7a and yb.

Excitation pulse signals Q, ~Q are supplied to the coil 9 of the stepping motor at timings based on M and H. Here, 10 is a power supply circuit for driving a stepping motor, and the power output is switched by a power supply switching driver (for example, an open collector transistor) 111 to which the output signal A of the monostable circuit 1 is normally applied.

This power supply circuit 10 outputs power to a driver circuit 8 via, for example, a Zener diode I2, and also outputs power to a coil 9 (
It also supplies power. In this case, the power supply circuit 10 is
Normally, a high voltage power source (for example, -1-V of 12V) is output at the beginning of driving the stepping motor, and then a low voltage aE power source (for example, 5.times.+2.times.2) is outputted to save power.

In addition, in the figure, RJ ~ I't 3 is a resistor, 138 ~ 1
3C is a capacitor, 14 is a transistor, and 15 is a diode.

The operation of this configuration will be explained. now,
When a step pulse SP as shown in FIG. 2 is output and applied to the monostable circuit 1 and the EX-OR circuit 3c, the output signal B of the monostable circuit 1 becomes rOJ. Due to this, the monostable circuit 2 is in an inoperable state. Therefore, as shown in FIG.
Both are rOJ, and the EX-OR circuit 3C outputs a pulse signal G synchronized with the step pulse SP. on the other hand,
A direction signal indicating the direction of rotation of the stepping motor, that is, the direction of movement of the magnetic head in the disk device is output, and is supplied to the EX-OR circuit 3b.

As a result, the EX-OR circuit 3b outputs an output signal H corresponding to the direction signal to the EX-OR circuits 6a and 6bl. The flip-flops 7a, 7b receive a signal G corresponding to the step pulse SP as a clock signal, and output signals K, L, M, according to the input of each output signal I, J of the EX-OR circuit a2.6b. Output N. As a result, the driver circuit 8 supplies excitation pulse signals Q, .about.Q, as shown in FIG. 2, to the coil 9 of the stepping motor. The stepping motor is rotationally driven with an excitation phase based on pulse signals Q, ~Q, and a signal D (
The magnetic head is moved in the corresponding direction (for example, toward the inner circumference of the disk surface) by the number of pulses of the step pulse SP (for example, 31-rack). When the magnetic head stops, data is read from and written to the disk surface at the stopped position.

By the way, as mentioned above, the operation of the stepping motor 1
- Therefore, if the magnetic head stops at a predetermined position, the stopping position is incorrect (it is located before the target position).
Suppose that an error occurs when reading or writing data. In this case, the controller of the disk device (not shown) outputs an error pulse signal BP as shown in FIG. 2 (not shown).

Here, the monostable circuit I has a step pulse SP
After a certain period of time after input stop +h, signal A.

Output B (which is rlJ). As a result, the monostable circuit 2 becomes operational, and the error pulse signal E
A pulse signal C having a constant pulse width synchronized with Pζ is output. This pulse signal C includes the characteristics of the stepping motor, and is a pulse set based on the rotation time of the stepping motor to the theoretical stop position (that is, the target stop position). The EX-OR circuit 3a outputs an output signal F as shown in FIG. 2 by being supplied with both the pulse signal c1 and the pulse signal C delayed by a certain period of time in the delay circuit 4b. From this, the EX OR circuit 3C outputs the signal F.
and step pulse SP (i.e., the generation of the pulse is stopped and is "1") (responsively, the pulse signal G as shown in FIG. 2 is output. This is as described above. Since the magnetic head has stopped before the target position, in order to cause the stepping motor to rotate in the normal direction again (rotation direction based on the signal DI), a pulse corresponding to the step pulse SP, which is an inversion of the signal F, must be output. By the way, the EX OR circuit 3a generates two pulses as the signal F at the front and rear edges of the pulse signal C using the delay circuit 4b and the pulse signal C. Among these, the first pulse (
F, ) in FIG. 2 sets the excitation phase of the stepping motor to the next state by one step in the forward rotation direction (timing X in FIG. 2). Therefore, the pulse signal C is delayed by the delay circuit 4a and applied to the EX-OR circuit 3bl, and the stepping motor is rotated in the forward direction while the signal F is maintained. The delay time in this delay circuit 4al is set so that the leading edge of the output signal H of the ID X-OR circuit 3b is between two pulses that are the output signal F of the EX-OR circuit 3a.

In this way, the first pulse F of the signal F.

With the signals G and H corresponding to , the stepping motor starts its rotor to move. Then, by the second pulse F2 and signal H, the excitation phase of the stepping motor is returned to its original state (that is, the horizontal magnetic phase when generation of the step pulse SP is stopped). As a result, the stepping motor only takes a small amount of time (
In other words, it is rotated by the time based on the pulse signal C),
Drive to the target stop position. Therefore, even if the stopping position of the magnetic head by the stepping motor is different from Purpose 1 due to the characteristics of the disk device (characteristics of the magnetic head and the friction system of the stepping motor, etc.), the stopping position can be changed to the target position as described above. This means that it can be corrected. In addition, in this case, the accuracy of position correction is improved by reducing the first movement phase (timing of X in Fig. 2) and performing the second movement (timing of Y in Fig. 2). You can also do that.

In the above embodiment ζ, the delay circuit (DL,
1) By removing 4a, a position correction operation can be performed when the stepping motor goes too far and stops.

〔Effect of the invention〕

As detailed above, according to the present invention, in positioning control of a magnetic head using a stepping motor, etc.
Even if the characteristic of the disk device is f, the stop position can be corrected in accordance with the larger amount l. Therefore, positioning control can be performed with high precision, and tracking failures of the disk device:ffi can be prevented.

Furthermore, when designing a disk mounting surface, it is no longer necessary to consider temperature, accuracy with respect to 7W degrees, etc., and accuracy with respect to a friction system when selecting component materials, making the design easier.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the stepping motor control circuit according to the present invention (stepping motion control circuit 2c).
+ is the timing 1000 yards to explain its operation. 1.2... Monostable multi-by-break, 3a
~,? C, t; a, 6 b...exclusive OR circuit, =ia, ,/b...delay circuit, 7a
, 7b... D-type flip 70 tube, 8..., driver circuit, 9. ,,coil. Applicant's agent Patent attorney Takehiko Suzue 61

Claims (1)

[Claims] In a stepping motor drive control circuit that performs positioning control from the rotational drive E of the stepping motor, the excitation phase of the stepping motor is controlled based on a step pulse corresponding to the positioning and a direction instruction signal that instructs the direction of the rotational drive. driver means for controlling;
After a certain period of time after the generation of the step pulses stops, the first pulse generating means outputs a predetermined pulse signal, and the first pulse generating means operates in synchronization with the pulse signal output from the first pulse generating means to generate a positioning error pulse signal. a second pulse generating means for outputting a pulse signal whose pulse width is set in advance based on the output; and a driving pulse signal corresponding to the step pulse based on the pulse signal generated from the second pulse generating means. and a logic gate circuit that outputs both of the driver means (and a logic gate circuit that outputs the signal corresponding to the direction instruction signal).