JPS60217558A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To supply an optimum output to a spindle motor by providing a driving circuit which detects load variation from past rotating speed data and readjusts the pulse width of control pulses on the basis of the mean value of the detected load variation. CONSTITUTION:Pulses outputted by a position detecting circuit 4 connected to the driving part 6 of the motor 2 which drives a magnetic disk 1 are detected and a microcomputer 5 performs next arithmetic. Speed data generated by measuring the period of the output pulses is added in a dedicated memory firstly and when the frequency of the addition attains to a specific value, the mean speed is calculated, conversion is performed with its check data according to a speed- pulse width conversion table, and the current speed check is made. Consequently, a current is supplied to the spindle motor 3 with pulses from the computer 5 and pulses from the circuit 4 to supply the optimum output.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a magnetic disk device.
Ru.

[Conventional technology]

Conventionally, as a spindle motor drive circuit for this pole of a magnetic disk drive, the one shown in FIG. 1 has rarely been used. In the figure, (11 is a magnetic disk, (2) is the above magnetic disk +1
1 is held by the spindle, (3 is the spindle holding the above spindle (2)
); (4) is a position detection circuit that detects the rotational position of the spindle motor (3);
(5) is a microcomputer system that detects multiple rotational speeds based on the output signal of the position detection circuit (4), and compares it with a predetermined speed value to reduce the output pulse width; (6) is the above-mentioned The spindle motor is driven by the output signal of the position detection circuit (4) and the output pulse of the microcomputer system (5).

Next, the operation will be explained. The period of the pulse output from the position detection circuit (1) is measured by the microcomputer system (5).The microcomputer system compares the period with the period corresponding to the preset rotation speed, and A pulse with the specified pulse width is output to the drive unit (6).The drive unit (6)
The phase in which the current of the spindle motor (3) should be adjusted is determined from the output pattern of the output circuit (4), and a current corresponding to the output pulse width of the microcomputer system (5) is supplied to the spindle motor (3) K. .

Figure 2 shows a timing chart of the position detection signal a!υ, which is the output pulse of the position detection circuit (410), and the control pulse (2), which is the output pulse of the microcomputer system (5). The vertical axis shows the end filling level of
In (2), the 9 units on the horizontal axis indicating time are measured in seconds.

FIG. 3 shows the relationship between the rotational speed deviation of the spindle motor (3) and the average value of the drive current.

Since the conventional spindle motor drive circuit is configured as described above, when the load on the shear spindle motor fluctuates due to environmental changes such as temperature and humidity.

It often had drawbacks such as fluctuations in rotational speed.

[Summary of the invention]

゛This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it averages the past rotational speed data and determines the pulse width of the control pulse based on the average.
The present invention provides a magnetic disk drive equipped with a spindle motor drive circuit that is not affected by load fluctuations of the shear spindle motor by adjusting t4+.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

The hardware configuration is basically the same JmM as the conventional one, but in this invention, the computer system (5) is the same as the above fIL+! The rotational speed is detected by the output signal of the IL output circuit (4), compared with a predetermined speed value, and the output is determined by referring to the average value of past rotational speed data. Ip! can be configured to reduce the pulse width by a fraction. I can copy it.

Next, the operation will be explained. When a pulse is output from the detection circuit (4), the microcomputer system (
5) detects this and starts a predetermined control operation. The control operation will be explained below with reference to the flowchart of FIG. First, the cycle of the output pulse of the preceding km output circuit (4) is measured by the speed setting routine to generate speed data (Sl). Next, calculate the speed data in a dedicated memory (
SL). Next, it is checked whether the number of times the sword has been calculated has reached a predetermined number (83), and if it has not reached the predetermined number, the process proceeds to the speed check routine (8B). Next, in a pulse duck decoration routine, pulse smoothness data corresponding to the speed check data is taken out from the conversion table, and the pulses are output to the m manufacturing department (S9). If the predetermined number of times has been reached in the 1,00 calculation count check, the average speed within a certain period of time is calculated by dividing the speed data obtained by the 7IO calculation by the predetermined number of times (S4). Next, check the average speed using the speed check routine (85).

Based on the check data, the velocity-pulse@henkyo table is modified (S6). After post-processing such as clearing the addition memory (87), the current speed check is performed (S8). In this way, the microcomputer system (5) outputs a pulse, and the output circuit (4) outputs that pulse and outputs a pulse from the output circuit (4) to the shear spindle motor (3). supply flow.

The gs diagram shows an example of the relationship between the rotation speed deviation of the spindle motor (3) and the average value of the drive current after changing the speed-pulse width variation table. In the figure, 1 point melting shows before the change, and real paddy shows after the change.

&O. In the above embodiment, pulse m control was shown in controlling the spindle motor, but the output may be an analog output.

[Young fruit of invention]

As described above, according to the present invention, load fluctuations are calculated from past rotational speed data and the output level is reset, so that load fluctuations of the spindle motor can be closely followed. effective.

[Brief explanation of the drawing]

Fig. 1 is a hardware diagram of a spindle motor drive circuit for explaining a conventional example and an embodiment of the present invention, Fig. 2 is a timing chart of a position detection signal and fBiJii1 pulse, and Fig. 3 is a conventional spindle motor drive circuit. Rotational speed deviation and output average of the drive circuit; Fig. 4 is a flowchart of the control operation according to an embodiment of the present invention; g5
The figure shows a rotation of 1M1M and an average output of 1! of a spindle motor drive circuit according to an embodiment of the present invention. It is a flow characteristic diagram. (1) is a magnetic disk, (2) is a spindle, +31U
Spindle motor, (4) is a position detection circuit, (5) is a microcomputer system, +e+hamm86° In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claim] A rotation control circuit for a spindle motor that rotates a magnetic disk based on the first position tk and the detected key signal. Detect load fluctuation from past rotational speed data and #I. A magnetic disk drive equipped with a spindle motor drive circuit that provides the optimal output for the current load.