JP2519524Y2 - Voltage controlled oscillation loop filter circuit - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention relates to a voltage-controlled oscillation (hereinafter referred to as "VCO") loop filter circuit, particularly a VCO loop that changes a capture range when driving a rotating disk.
Regarding a filter circuit.

2. Description of the Related Art Conventionally, when a rotary disc is driven, a motor that rotates the rotary disc and a pickup unit that detects a signal of the rotary disc are driven by a driver, and the driver is controlled by a control unit and a processing unit (CPU). Is. The control unit is composed of a phase comparator, a filter, a VCO VCO loop circuit, a constant linear velocity circuit (CLV), and the like.

That is, the frequency of the signal detected by the pickup unit is
When the frequency is input to the VCO loop circuit and the free-running frequency of the VCO loop circuit is synchronized, the CLV controls the motor by the frame synchronization signal so that the linear velocity of the outer and inner circumferences of the rotating disk becomes constant. . In this case, the frequency range in which the frequencies are synchronized (locked) is called the lock range, and the frequency range between the rising threshold and the falling threshold of the locked frequency range is called the capture range.

Here, the capture range can be switched in order to enable an access operation when the free-running frequency shifts. A VCO loop filter circuit in this case is shown in FIG. In FIG. 3, a capacitor C ₁₁ is connected in parallel to a series circuit of a capacitor C ₁₀ and a resistor R ₁₀ from a filter 30 (pulse width modulation carrier component removal filter) of the VCO loop circuit and grounded. The connection point of the capacitor C ₁₀ and resistor R ₁₀ is connected the collector of the transistor Tr ₁₀ is, the emitter is grounded. Then, a frame synchronization signal (GFS) is input to the base of the transistor Tr ₁₀ from the pickup section via the control section.
That is, when GFS is at a high level (frame synchronization locked state), the transistor Tr ₁₀ is in the on state, and operates in the capture range set in the play state.
On the other hand, at the time of access such as a track jump, GFS becomes low level and the transistor Tr ₁₀ is turned off. When the transistor Tr ₁₀ is turned off, the circuit constant is changed by the resistor R ₁₀ , and the cutoff frequency in the filter 30 is changed, so that the capture range is maximized. This facilitates pulling into the locked state during access.

However, the GFS signal changes from the low level to the high level during the search for each access jump even during the access of the track jump, for example. In this case, immediately after the capture range is switched from a wide range to a narrow range, VC rises due to the delay in the rise time of transistor Tr ₁₀ and other factors.
There is a problem that the O is not pulled into the locked state, the motor is disturbed, and the whole access time is delayed.

Then, this invention is made | formed in view of the said subject, and it aims at providing the VCO loop filter circuit which prevents delay of access time.

Means for Solving the Problems In order to solve the above problems, the present invention focuses on maintaining a constant circuit constant in a cutoff circuit for switching a capture range, and has the following configuration. .

A motor for driving a rotating disc on which information is recorded,
A voltage-controlled oscillation loop filter circuit for controlling the rotation of the motor of a rotating disk drive device comprising a head for reading information recorded on the rotating disk, the frame being extracted from a read signal from the head. A voltage control oscillation loop whose oscillation frequency is controlled based on the frequency of a synchronization signal, wherein the voltage is within a capture range that is a frequency range in which the frequency of the frame synchronization signal and the free-running frequency of the voltage control oscillation loop are synchronized. In a voltage controlled oscillation loop filter circuit that controls the rotation of the motor based on the output of a controlled oscillation loop, the voltage controlled oscillation loop includes a frequency of a frame synchronization signal extracted from a read signal from the head and the voltage control. Generates a sync signal (GFS) that indicates that the free-running frequency of the oscillation loop is synchronized. The voltage-controlled oscillation loop filter circuit is provided with a cut-off circuit for changing the capture range of the voltage-controlled oscillation loop by switching a circuit constant, and when the track jump is accessed, the head is When there is a signal from the outside that indicates that a track jump is being accessed to the rotating disk, the cut-off circuit is operated to expand the capture range regardless of the presence or absence of the sync signal (GFS). Is characterized by.

Operation The present invention has a switching means for switching the capture range in the cutoff circuit. This switching is performed not only by the synchronizing signal from one voltage controlled oscillation loop but also by the signal indicating that the track jump is being accessed. Therefore, during a predetermined operation, the capture range can be maintained within a fixed range without switching, the VCO in the motor drive can be easily pulled into the locked state, and the motor disturbance can be prevented. This allows
Delays in overall access time during a given operation are prevented.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block circuit diagram for driving a rotating disk by a VCO (voltage controlled oscillation) loop filter circuit of the present invention. In FIG. 1, a rotating disk 1 is rotated by, for example, a spindle motor 2, and a pickup (PU) unit 3 detects a signal. The spindle motor 2 and the pickup unit 3 are driven by a driver 4. The control unit 5 inputs the detection signal of the pickup unit 3 to the phase comparator 6, and the phase comparator 6, the filter 7, and the VCO 8 make the VCO
Make a loop. The output of VCO 8 is output to CLV (constant linear velocity circuit) 9, and CLV 9 controls driver 4.
The central processing unit (CPU) 10 sends and receives various signals such as a mute signal (MUTG) to the control unit 5. On the other hand, the filter 7 is provided with a cutoff circuit 11 and a switching means 12. That is, in the cutoff circuit 11, the capacitor C ₂ is connected in parallel to the series circuit of the capacitor C ₁ and the resistor R ₁ from the filter 7, and is grounded. The collector of the transistor Tr ₁ is connected to the connection point between the capacitor C ₁ and the resistor R ₁ , and the emitter is grounded. Then, GFS (frame synchronization signal) is applied from the control unit 5 to the base of the transistor Tr ₁ via the resistor R ₂ and is also supplied to the collector of the transistor Tr ₂ . The emitter of the transistor Tr ₂ is grounded, and MUTG (silence signal) is applied from the CPU 10 to the base. The transistor Tr ₁ and the transistor Tr ₂ constitute a switching means 12 for switching the capture range.

In the above block circuit diagram, first, the detection signal of the pickup unit 3 is compared with the continuous signal of the free-running frequency in the VCO 8 by the phase comparator 6 of the control unit 5, and CLV9 is synchronized until the lock state is achieved within the capture range. Controls the motor 2 via the driver. In this case, the filter 7 removes the carrier component of the pulse width modulation (PWM) of the phase comparator 6 and changes the capture range of the cutoff circuit 11 by the switching means 12. Here, when the operation state is the play state, GFS (frame synchronization signal) in the control unit 5 is at high level, and MUTG (silence signal) from the CPU 10 is at low level. Therefore, the transistor Tr ₂ is turned off and the transistor Tr ₁ is turned on.
As a result, the cut-off circuit constant of the filter 7 is determined by the parallel circuit of the capacitors C ₁ and C ₂ , and the motor 2 is controlled in the capture range of the play operation.

Next, the case where the operation state is the access state will be described with reference to the time chart of FIG. FIG. 2 shows a case where a track jump is performed, for example. 10 in access status
When jumping 0 tracks (Fig. 2 (A)), GFS
The (frame synchronization signal) falls to the low level during the jump, and at the same time, the MUTG (silence signal) becomes the high level (FIGS. 2 (B) and (C)). Here, GFS is low level only during jump even if it is in access status, and becomes high level during search, but MUTG is GFS during access.
Maintain high level regardless of. Therefore, referring back to FIG. 2, the MUTG is at the high level and the transistor
Since Tr ₂ is turned on, transistor Tr ₁ is turned off regardless of GFS. Therefore, the circuit constant of the cutoff circuit 11 changes due to the resistance R ₁ . As a result, the cutoff frequency in the filter 7 is narrowed and the capture range is maximized.

In this way, the capture range is always expanded in the access state, and the capture range is expanded even during the search in the track jump. Therefore, the spindle motor 2 performs a smooth search without causing disorder. Therefore, there is no delay in the total access time.

As described above, according to the present invention, the cutoff circuit for switching the capture range is provided with the switching means for switching with any one of a plurality of signals, so that the delay of the entire access time can be prevented. It is possible to maintain a smooth access operation state.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an embodiment of the present invention, FIG. 2 is a time chart of the access state in FIG. 1, and FIG. 3 is a circuit diagram showing a conventional VCO loop filter circuit. 1 ... Rotating disk, 2 ... Spindle motor, 3 ...
Pickup (PU) part, 4 ... Driver, 5 ... Control part, 6 ... Phase comparator, 7 ... Filter, 8 ... VCO,
9 …… CLV, 10 …… CPU, 11 …… Cutoff circuit, 12 ……
Switching means.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takehiro Ishikawa 960 Itoda Co., Ltd., Isehara City, Kanagawa Prefecture Toda Corp. B (72) Inventor, Sachio Ide, 1103 Tsurumaki, Hadano City, Kanagawa Prefecture 101, Fukagawa Corp. (72) Inventor, Kirii Atsushi Yamagata Prefecture 630-3 Oishida Ko, Oishida-cho, Kitamurayama-gun (56) Reference JP-A 1-253832 (JP, A) JP-A 59-12168 (JP, A) JP-A 59-71166 (JP, A) Actual development Sho 62-2392 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. A voltage-controlled oscillation loop for controlling rotation of the motor of a rotary disk drive device, comprising a motor for driving a rotary disk on which information is recorded, and a head for reading information recorded on the rotary disk. A filter circuit, comprising a voltage control oscillation loop whose oscillation frequency is controlled based on the frequency of the frame synchronization signal extracted from the read signal from the head, wherein the frequency of the frame synchronization signal and the voltage control oscillation loop In a capture range, which is a frequency range in which the free-running frequency of the voltage control oscillation loop is synchronized, in a voltage control oscillation loop filter circuit that controls rotation of the motor based on the output of the voltage control oscillation loop, the voltage control oscillation loop is Frequency of frame sync signal extracted from read signal from head and voltage controlled oscillation The voltage-controlled oscillation loop filter circuit switches a circuit constant to generate a synchronization signal (GFS) indicating that the voltage-controlled oscillation loop is synchronized with the free-running frequency of the loop. It is equipped with a cut-off circuit that changes the range. When there is a track jump access, and there is an external signal that indicates that the head is accessing the rotating disk for a track jump, the sync signal (GFS ), The voltage controlled oscillation loop filter circuit is characterized in that the cutoff circuit is operated to expand the capture range.