JPH03266259A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To manage with one set of a microprocessor, and to realize the miniaturization and the cost reduction of a device by controlling the movement and the positioning of an actuator, and simultaneously, calculating duty ratio by the single microprocessor. CONSTITUTION:The revolution detection signal of a DC motor 18 is supplied to a position difference detection circuit 25, and is compared with the revolution detection signal from a terminal 17, and phase difference between both the signals is supplied to the microprocessor 26. The microprocessor 26 executes the control processing of the movement and the positioning of the actuator 13 and the recording and reproducing processing of data in conformity to the instruction of a host device 11, and simultaneously, it reads the phase difference of the phase difference detection circuit 25 by using idle time, and obtains the adequate revolving speed of the DC motor 18, and calculates the duty ratio of a pulse width modulation (PWN) signal for it, and sets this duty ratio in a PWM output circuit 27. According, the calculation of the duty ratio can be executed together with the moving.positioning control of the actuator 13 by the single microprocessor 26. Thus, one set of the microprocessor is enough, and the miniaturization and the cost reduction of the device are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic disk device, which uses a microprocessor to control disk rotation and actuator movement.
The present invention relates to a magnetic disk device that performs positioning control.

In recent years, fixed magnetic disk drives have been used mainly for the purpose of high-speed data transfer, by synchronizing the rotation of the disks of multiple fixed magnetic disk drives, making it possible to read data from multiple fixed magnetic disk drives at once. . It is required that this rotation synchronization function be built into the main body of a fixed magnetic disk device.

[Conventional technology]

FIG. 4 shows a block diagram of an example of a conventional device.

In the figure, a microprocessor 10 performs movement and positioning control processing for the actuator 13 according to instructions from a host device 11, and a servo circuit 2812 moves the actuator 13 according to the control signal, and a read/write circuit 14 sends a read/write head. to record and reproduce data.

The microb0 setter 16 generates a pulse width modulation (PWM) signal so that the rotation detection signal of the DC motor 18 is synchronized with the rotation synchronization signal input from the terminal 17, and controls the DC motor 1.
8 and its rotation is controlled, and the disk 19 is rotated by the DC motor 18.

(Problems to be Solved by the Invention) In the conventional device, the microprocessor 16 always generates a PWM signal and supplies it to the DC motor 18.

Therefore, the processing executed by the microprocessor 10 and the processing executed by the microprocessor 16 cannot be executed by a single microprocessor, and two microprocessors 10.16 are required, which becomes an obstacle to miniaturizing the device. However, there was a problem that the equipment was expensive.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a magnetic disk mounting device that can be miniaturized and inexpensive.

(Means for Solving the Problems) A magnetic disk device of the present invention is a magnetic disk device that performs disk rotation control and actuator movement/positioning control. A phase difference detection circuit detects the phase difference with the signal, controls the movement and positioning of the actuator according to instructions from the host device, and generates pulses to bring the DC motor to the desired rotation speed based on the phase difference from the rotation detection circuit. a single microprocessor that calculates a duty ratio of a width modulation signal; a pulse width modulation signal output circuit that generates a pulse width modulation signal according to the duty ratio set by the microprocessor and supplies it to the drive section of the DC motor; has.

[Effect]

In the present invention, the microprocessor uses the phase difference detected by the phase difference detection circuit to find the duty ratio and simply sets it in the pulse width modulation signal output circuit, so that the pulse width modulation signal output circuit generates the pulse width modulation signal. , the duty ratio can be calculated together with the movement and positioning control of the actuator by setting the microb 0 in A-A. Therefore, only one microprocessor is required, making the II smaller and cheaper.

(Embodiment) FIG. 1 shows a block diagram of an embodiment of the apparatus of the present invention. In this figure, the same parts as in FIG. 4 are given the same reference numerals, and their explanations will be omitted.

In FIG. 1, the rotation detection signal of the DC motor 18 is supplied to a phase difference detection circuit 25, where it is compared with the rotation detection signal from the terminal 17, and the phase difference between the two signals is supplied to the microprocessor 26. Ru.

Like the microprocessor 10 of the conventional device, the microb0 setter 26 performs movement and positioning control processing of the actuator 13 and data recording/reproduction processing according to instructions from the host device 11, and also uses free time to control the phase difference detection circuit 25. The appropriate rotational speed of the DC motor 18 is determined by reading the phase difference, the duty ratio of the PWM signal for that purpose is calculated, and this duty ratio is set in the PWM output circuit 27.

The PWM output circuit 27 outputs PW from the set duty ratio.
The pulse width of the M signal is determined and this PWM signal is supplied to the decoder 28. This duty ratio does not need to be set all the time; until it is reset by the microprocessor 26, the P
Outputs WM signal.

The decoder 28 and the DC motor 18 have the configuration shown in FIG. In the figure, position sensors U, V in the DC motor 18,
Figure 3 (A) shows the detection of each W.

The rotation detection signals shown in (B) and (C) are sent to the decoder 28.
3 (D>, (E)).

(F) Shaped into rectangular waves u', v', and w' shown respectively. Further, the decoder 28 is connected to the terminal 31 as shown in FIG.
) is input. The decoding circuit receives the switching signals UT, UB, VT, VB, WT, W shown in FIG. 3 (H) to (M) from the rectangular waves u', v', w'.
When the PWM signal is at L level, all switching signals are at L level. The above switching signal is generated by the following equation.

UT=PWM-u'(-V')UB=PWM
・(-u')-v'VT=PWM・v'(-w')VB=PWM
-(-V')-W'WT=PWM-w'(-u')WB=PWM-(-W')-Ll' Switching of transistors 01 to Q6 of the current driver using the above switching signals UT-WB, respectively to control the DC motors 18's L+ and L2.

A drive current is applied to L3.

In this way, the microprocessor 26 uses the phase difference detected by the phase difference detection circuit 25 to determine the duty ratio and calculates the PW
Since the PWM output circuit generates a pulse width modulation signal by simply setting it in the M output circuit 27, it is possible to control the movement and positioning of the actuator 13 and calculate the duty ratio with a single microbe O set+J26. Therefore, only one microprocessor is required, and the device can be made smaller and less expensive.

〔Effect of the invention〕

As described above, the magnetic disk device of the present invention is operated by a single microprocessor, making the device compact and low in temperature, making it extremely useful in practice.

Figure 3 is a signal timing chart of each part of the circuit in Figure 2, FIG. 4 is a block diagram of a conventional circuit.

In the figure, 11 is placed in the top 5A, 13 is an actuator; 18 is a DC motor, 19 is a disk, 25 is a phase difference detection circuit; 26 is a microprocessor; 27 is a PWM output circuit, 28 is a decoder shows.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the circuit of the present invention, Fig. 2 is a block diagram of a decoder and a DC motor,
Blow/Figure 2 decoder and 0゛ze]Ll-J'-Figure 2

Claims (1)

[Claims] In a magnetic disk device that controls disk rotation and movement and positioning of an actuator, a phase difference between a rotation detection signal of a DC motor (18) for disk rotation and a reference rotation synchronization signal is detected. Phase difference detection circuit (2
5) and the actuator (1) according to instructions from the host device (11).
3), and also determines the duty ratio of a pulse width modulation signal to bring the DC motor (18) to a desired rotational speed from the phase difference from the rotation detection circuit (25). a microprocessor (26); and a pulse width modulation signal that generates a pulse width modulation signal according to the duty ratio set by the microprocessor (26) and supplies the pulse width modulation signal to the drive unit (28) of the DC motor (18). A magnetic disk device characterized by having an output circuit (27).