JPH03222153A - Spindle motor control circuit for magnetic disk device - Google Patents

Abstract

PURPOSE:To shorten reset time to a steady state, and to suppress power consumption at the time of re-start by making a steady rotational speed signal from a spindle motor and a reduced rotational speed signal slower than it into a standard by switching them by a rotation waiting signal from a host device. CONSTITUTION:The rotation waiting signal 14 is sent from the host device, and controls the selection of the rotational speed of the spindle motor 10. A selection circuit 13 instructs to select to use either the steady rotational speed signal 11 or the reduced rotational speed signal 12 as the reference speed signal 3 of the revolution of the motor by the signal 14. Thus, at the time of the re-start of a device, the time required for resetting the motor 10 to the steady state that it can operate is shortened, and simultaneously, the power consumption can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spindle motor control circuit for a magnetic disk drive, and in particular to a magnetic disk drive that controls the rotational speed of a spindle motor by comparing a reference speed signal and a rotational speed pulse. The present invention relates to a spindle motor control circuit for an apparatus.

[Conventional technology]

FIG. 2 is a block diagram showing an example of a spindle motor control circuit of a conventional magnetic disk device.

In FIG. 2, a rotation speed detection circuit 1 is a circuit that detects the rotation speed of the spindle motor 10, and generates a speed signal 2 corresponding to the rotation speed of the spindle motor 10. The reference speed signal 3 is a reference signal for controlling the rotational speed of the spindle motor 10, and indicates the rotational speed of the spindle motor 10 during steady rotation. Pulse width modulation circuit 4
is a rotational speed pulse 5 having a width corresponding to the rotational speed of the spindle motor 10 from the reference speed signal 3 indicating the rotational speed of the spindle motor 10 during steady rotation and the speed signal 2 corresponding to the rotational speed of the spindle motor 10. occurs. The comparison circuit 6 generates a rotation speed pulse 5 having a width corresponding to the rotation speed of the spindle motor 10 and a reference speed signal 3 indicating the rotation speed of the spindle motor 10 during steady rotation.
A control current 7 is generated according to the difference between the two.

The power amplifier 8 amplifies the control current 7 to generate an output current 9 for controlling the rotational speed of the spindle motor 10, thereby controlling the rotational speed of the spindle motor 10 according to the reference speed signal 3 to be kept constant. do.

[Problem to be solved by the invention]

Generally speaking, for magnetic disk drives (devices) and spare magnetic disk drives (devices) that do not receive many commands from a host device, it is desirable to stop the rotation of the spindle motor from the viewpoint of power consumption. If the rotation of the motor is stopped, the rotation state of the spindle motor when the device is restarted will take a considerable amount of time to return from the stopped state to a steady state in which the device can operate. When the spindle motor starts rotating, there is a large temperature rise in the device due to heat generated by the rotation of the magnetic disk plate, so the reliability of data may be low even if data is read or written until the temperature of the device stabilizes. Therefore, as mentioned above, in conventional magnetic disk drives, the rotational speed of the spindle motor is always maintained at a steady speed even in devices that do not receive many commands from the host device or in standby devices. It has the disadvantage of consuming power.

[Means to solve the problem]

A spindle motor control circuit for a magnetic disk device according to the present invention includes a spindle motor, a rotation speed detection circuit that detects the rotation speed of the spindle motor, and a speed signal from the rotation speed detection circuit that controls the rotation speed of the spindle motor. a pulse width modulation circuit that inputs a reference speed signal to output a rotation speed pulse having a width corresponding to the rotation speed of the spindle motor; and a pulse width modulation circuit that inputs and compares the rotation speed pulse and the reference speed signal. In a spindle motor control circuit of a magnetic disk device, which includes a comparison circuit that outputs a control signal according to the difference between the two, and a power amplifier that inputs the control signal and supplies an amplified output current to the spindle motor, A steady rotation speed signal indicating a rotation speed and a deceleration rotation speed signal indicating a rotation speed slower than the steady rotation speed are input, and one of them is set as the reference speed signal by a rotation standby signal input from a host device. It is equipped with a selection circuit for output.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

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

In FIG. 1, a steady rotational speed signal 11 is a signal indicating the rotational speed of the spindle motor 10 during steady rotation,
The deceleration rotational speed signal 12 is a signal that indicates a rotational speed of the spindle motor 10 that is slower than in a steady state. The rotation standby signal 14 is a signal sent from a host device,
This is a signal that controls selection of the rotation speed of the spindle motor 10. The selection circuit 13 uses the steady rotation speed signal 11 as the reference speed signal 3 for the rotation of the spindle motor 10 or uses the deceleration rotation speed signal 1 according to the rotation standby signal 14.
This is a signal instructing the selection of whether to use 2. When the rotation standby signal 14 is active, the decelerated rotation speed signal 12 is selected as the reference speed signal 3, and when the rotation standby signal 14 is inactive, the steady rotation speed signal 11 is selected as the reference speed signal 3. As a result, when the rotation standby signal 14 is active, the rotation of the spindle motor 10 is decelerated rotation, and when the rotation standby signal 14 is active, the rotation of the spindle motor 10 is steady rotation.

The structure and operation other than those described above are the same as those of the conventional example shown in FIG.

〔Effect of the invention〕

As explained above, the spindle motor control circuit for a magnetic disk device of the present invention increases the rotational speed of the spindle motor when restarting the device, thereby shortening the time it takes for the device to return to a steady state in which it can operate. Moreover, it has the effect of suppressing power consumption.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a spindle motor control circuit of a conventional magnetic disk device. 1... Rotation speed detection circuit, 2... Speed signal, 3... Reference speed signal, 4... Pulse width modulation circuit, 5...・Rotation speed pulse, 6...
... Comparison circuit, 7 ... Control current, 8 ...
...Power amplifier, 9...Output current, 10.
... Spindle motor, 11 ... Steady rotation speed signal, 12 ... Deceleration rotation speed signal, work 3
...Selection circuit, ■4...Rotation standby signal.

Claims (1)

[Claims] A spindle motor, a rotation speed detection circuit that detects the rotation speed of the spindle motor, and a speed signal from the rotation speed detection circuit and a reference speed signal for controlling the rotation speed of the spindle motor are inputted to control the spindle motor. a pulse width modulation circuit that outputs a rotational speed pulse having a width corresponding to the rotational speed of the motor; and a comparison circuit that inputs and compares the rotational speed pulse and the reference speed signal and outputs a control signal according to the difference. and a power amplifier that inputs the control signal and supplies an amplified output current to the spindle motor, wherein A magnetic disk device characterized by comprising a selection circuit which inputs a deceleration rotational speed signal instructing a rotational speed slower than the reference speed signal and outputs one of them as the reference speed signal in response to a rotation standby signal inputted from a host device. spindle motor control circuit.