JPH0522980A - Spindle motor control circuit of magnetic disk apparatus - Google Patents

Abstract

PURPOSE:To control the number of rotations of motor only with modification of programs stored in the CPU without changing circuit configuration even for change of the number of poles of motor. CONSTITUTION:A spindle motor control circuit of magnetic disk apparatus comprising a plurality of Hall sensors 6 for detecting rotating angle of a rotor, a frequency divider 2 for dividing an output of only one sensor 1 to 1/2n (n is a natural number), a selector 3 for selecting a plurality of output signals of the frequency divider to determine a dividing ratio and a CPU 4 for obtaining the number of rotations by detecting period of frequency-divided outputs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor control circuit for a magnetic disk.

[0002]

2. Description of the Related Art Conventionally, there is a rotation speed detection circuit of a spindle motor of this type of magnetic disk device as shown in FIG.

In FIG. 3, n / 2 (n: number of poles) pulses are output to the hall sensor 6 per rotation by the rotation of the spindle motor). This is divided by the frequency divider 2, converted into one pulse per one rotation, and applied to the CPU 4. The CPU 4 knows the rotation cycle by measuring the pulse interval, and issues a torque command to the driver 5, and accordingly the driver 5 controls the speed by adjusting the current supplied to the spindle motor.

FIG. 4 shows another conventional example, in which the counter electromotive voltage generated by the rotation of the spindle motor is compared by the comparator 7 between each phase, and n / per rotation is obtained.
2 (n: number of poles) pulses are output. This is frequency-divided by the frequency divider 2, and speed control is performed in the same manner as in the example of FIG.

[0005]

In the spindle motor control circuit of the above-mentioned conventional magnetic disk device, since the frequency division ratio is fixed, the frequency divider is reactivated when the number of poles of the spider motor is changed. It has the drawback of having to be designed.

[0006]

A spindle motor control circuit of a magnetic disk apparatus according to the present invention detects a pulse generated by rotation of a motor and outputs the output of one of the detectors to 1 / 2n (n). Is a natural number), a selector that selects a plurality of signals output from the frequency divider, determines the division ratio, and detects the cycle of the divided output to determine the rotation speed. It is characterized by having a required CPU.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

In FIG. 1, the pulse output from the Hall sensor 6 in accordance with the rotation of the spindle motor is input to the frequency divider 2, and the output is 1/2, 1/4, ... 1/2.
The frequency is divided into n, and each output is input to the selector 3.

The output of the selector 3 is output by the CPU based on data programmed in advance according to the number of poles of the motor.
4 is selected, the divided output is input to the CPU 4, the time of one cycle is measured, and the speed of the spindle motor 1 is controlled.

FIG. 2 is a block diagram of an embodiment of the present invention, in which the counter electromotive current generated by the rotation of the spindle motor 1 is compared by the comparator 7 between the respective phases and inputted to the frequency divider 2 as a pulse. 1 / as in example 1
The frequency is divided into 2, 1/4, ... 1 / 2n and input to the selector 3. Thereafter, speed control is performed in the same manner as in the example of FIG.

[0012]

As described above, according to the present invention, the pulse generated with the rotation of the motor is divided by a plurality of division ratios.
By selecting the output according to the number of poles of the motor and using it as a signal for knowing the rotation cycle, there is an effect that only the program of the CPU needs to be changed without changing the circuit by changing the number of poles of the motor.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of another conventional example of the present invention.

FIG. 3 is a block diagram of a conventional example.

FIG. 4 is a block diagram of another conventional example.

[Explanation of symbols]

1 Spindle motor 2 frequency divider 3 selector 4 CPU 5 drivers 6 Hall sensor 7 comparator 8 resistance

Claims (2)

[Claims] 1. A plurality of Hall sensors for detecting a rotation angle of a rotor, a frequency divider that divides one output into 1 / 2n (n is a natural number), and a plurality of outputs from the frequency divider. A spindle motor control circuit for a magnetic disk device, comprising: a selector that selects a signal to be selected and determines a frequency division ratio; and a CPU that detects the frequency of the frequency-divided output and obtains the number of revolutions by the CPU. 2. A circuit for detecting a counter electromotive voltage generated by the rotation of a rotor, a frequency divider for dividing one output of a detected signal into 1 / 2n (n is a natural number), and a frequency divider. A spindle for a magnetic disk device, comprising: a selector for selecting a plurality of signals output from the power supply device to determine a frequency division ratio; and a CPU 4 for detecting a frequency of the frequency-divided output to obtain a rotation speed. Motor control circuit.