JPH0295191A - Rotational frequency controller for motor - Google Patents

Abstract

PURPOSE:To change a rotational frequency quickly and stably, and to realize a fast access time by detecting the change of a speed control signal and generating an acceleration signal or a deceleration signal. CONSTITUTION:In as rotational frequency controller for a DC motor whose rotational frequency is variable, means 10, 12, 13 detecting the level of a speed control output at the time of the transition of the rotational frequency and outputting an acceleration signal S15 and a deceleration signal S16 are provided. Means 14, 15, 19 detecting the level of a phase control output and outputting a rotational frequency lock signal S3 are furnished. A circuit detecting the levels of the speed control output and the phase control output is constituted by using comparators 12, 13, 14, 15. Consequently, the acceleration signal S15 and the deceleration signal S16 are generated on the transition of the rotational frequency. Accordingly, the transition time is shortened, thus shortening the access time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a DC motor rotation speed control device, and relates to a reverse torque brake mechanism included in a rotation speed control circuit of a spindle motor (DC brushless motor) in an information recording and reproducing device. , a positive torque acceleration mechanism, and a rotation speed lock signal.

[Prior Art] Conventionally known information recording and reproducing devices are numerically composed of a spindle motor that rotates a disk-shaped recording medium at high speed, and a head unit that performs recording and reproducing.

Furthermore, since large capacity and high transfer rate and high speed access are required, spindle motors are required to have high rotation accuracy, high rotation, fast start-up, and quick stop operation.

In order to meet these demands, DC three-phase brushless motors are often used as spindle motors for information recording devices.

FIG. 3 shows a conventionally known spindle motor control circuit. Here, 1 is a motor driver (IC), which has an FG amplifier 2 built therein. 34.5 is each phase (U
, V, W). 6, 7.8 are each phase (U
, V, W).

That is, the rotor is rotated by detecting the rotational phase angle of the rotor (not shown) by the Hall element 67.8 and bipolar driving any two of the drive coils.

9 is an FG coil, and lO is a servo control IC. This servo control 1010 uses the FG signal (S7)
A speed comparison and a phase comparison are performed using a reference clock (S2), and the results are output as a speed control signal (S5) and a phase control signal (S6), respectively. After the speed control signal (S5) and the phase control signal (S6) are added, they are manually input to the motor driver (IC) 10 control signal input S8 through the diode D1. S4 is the brake output, and the motor driver (
IC) 1 is connected to the rotational direction human power S9 and to the control signal human power S8 via the diode D2. Diodes DI and D2 are for switching.

Next, the operation of the motor drive circuit shown in FIG. 3 will be explained using FIG. 4. Motor 0N (51) (t+)(-
means low level) Then, the control signal S8 becomes high level, and the motor accelerates. When the motor rotation speed becomes close to the target (t2), the rotation speed Lock signal becomes Low level, the speed control output S5 and the phase control output S6 are fed back to the control signal S8, and constant speed rotation is realized. Here, the rotation speed Lock signal is about -5 of the target rotation speed.
Output when the percentage is reached.

Then, recording and reproduction are performed while the motor is rotating at a constant speed with an error of about ±0.1%.

In disc-shaped recording media, the outer and inner circumferences have different lengths, so in order to increase the recording density and transfer rate, the rotation speed is slowed down at the outer circumference and increased in steps toward the inner circumference (M
CAV) may be taken. The operation at this time will be explained next using FIG. 4.

From time t, it rotates (rotation number ω1) at the frequency f1 of the reference clock S2. At t3, change the frequency from fl to f
Raise it to 2. The motor is accelerated and reaches the target rotation speed ω at L4.
2 rotates at a constant speed. Next, at t5, the reference clock 52 is set to f.

Lower it from f3. The control signal S8 becomes 0 volts, but
Since the brake output S4 is at the 1.0W level, no deceleration force is generated. The motor rotates due to inertia and finally reaches ω3 at time t6.
Rotates at a constant speed. The rotation speed transition time Δτ is Δτ (low speed → high speed) (Δτ (high speed − low speed)).

When the motor is turned off at time t7, the brake output S4 of the motor control 1010 becomes High and reverse torque is generated, so the motor rapidly decelerates and stops at time t8.

[Problems to be Solved by the Invention] As described above, the circuit configuration of the conventional example described above has the following drawbacks because the accelerating force is small and no decelerating force is generated when changing the rotational speed.

(1) It takes a long time to transition from one rotational speed to a different rotational speed, and the access time becomes long.

Further, since the rotation speed lock signal is output when the rotation speed reaches approximately -5% of the target rotation speed, there are the following drawbacks.

(2) Since recording and reproduction are not possible unless the rotational fluctuation is about ±0.1%, the rotational speed lock signal cannot be used as a discrimination signal.

SUMMARY OF THE INVENTION Therefore, in view of the above-mentioned points, an object of the present invention is to provide a motor rotation speed control device that can always quickly switch the rotation speed and use a rotation speed lock signal to determine whether recording and reproduction are possible or not. It's about doing.

The circuit can be configured using, for example, a comparator.

[Function] The motor rotation speed control device according to the invention generates an acceleration signal and a deceleration signal at the time of rotation speed transition, thereby shortening the transition time and shortening the access time.

Further, the range of the rotational speed Lock signal is set to, for example, ±0.1% of the target rotational speed, and it is determined whether recording and reproduction are possible or not based on the rotational speed Lock signal.

[Means for Solving the Problems] In the present invention, in a rotation speed control device for a DC motor having a variable rotation speed, means is provided for detecting the level of a speed control output at the time of a rotation speed transition and outputting an acceleration signal and a deceleration signal. Be equipped.

In addition, the level of the phase control output is detected and the rotation speed Lo
A means for outputting a k signal is provided.

Detecting the Levels of Speed Control Output and Phase Control Output [Embodiment] Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.

According to a preferred embodiment of the present invention, in the rotation speed control circuit of a DC brushless motor, a change in the speed control signal is detected when switching the rotation speed to form an acceleration signal or a deceleration signal;
This speeds up the access time by shortening the rotation speed transition time. Also, when establishing the rotation speed, a change in the phase control signal is detected to form a rotation speed Lock signal, and the rotation speed Lock is detected.
This makes it possible to determine whether recording/reproduction is possible or not based on the k signal. That is, by detecting changes in the phase control signal, it is possible to detect rotational fluctuations of about ±0.1%.

FIG. 1 shows an embodiment of the invention. Here, explanations of elements that overlap with those in FIG. 3 will be omitted. 11 is a programmable counter, which manually sets the reference clock from S2;
The clock whose frequency is divided by the frequency division ratio determined in 11.12 and 13.14 is output from 510. 12. +3.14
゜15 is a comparator, and each reference voltage is set to v.
3. v,,v2. Let v. And V3<L, V
There is a relationship of l<V2.

When the speed control signal V, is V>V<, an acceleration signal (-Vcc) is output to S15.

V, X<V3 (516 km deceleration signal (-Vcc when D)
) is output.

The phase control signal V is V, <Vp<V2 At this time, a rotation speed lock signal (20v) is output.

Comparators 12 and 13 compare speed control signals, and comparators 14 and 15 compare phase control signals. Each output is pulled up to the power supply voltage through R1, R2, R3, and R4. 16 is an inverter, 17 is an AND gate, 18 is an OR gate, and 19 is a NAND gate.

D3 is a switching diode, DI, D2
It has the same function as .

Next, the operation of this embodiment will be explained using FIGS. 1 and 2. FIG. 2 is a timing chart.

The motor is turned on at time t1. Speed control signal v1. ．． Both the phase control signal V and the phase control signal V are saturated near the power supply voltage (~Vcc). The output 515 of the comparator 13 is the old GH (
-Vcc), and the motor accelerates. Since V, > V2, the rotation speed lock signal is the old gh (~Vcc). The motor has maximum acceleration and reaches the rotational speed ω1 at time t2.

At time t3, the rotation speed is increased from ω1 to ω2. The speed control signal V becomes v, JJ>v4, the phase control signal VP becomes vP>v2, an acceleration signal is output to S15, and the motor is set at maximum acceleration to the rotational speed ω2 at time t4. Rotation speed Lock
The signal becomes old gh when the motor accelerates, and the rotation speed error is ±
If it is set at around 0.1%, it becomes L6w.

Next, at time t5, the rotation speed is decreased from ω2 to ω3. The speed control signal V is V, <V3, and the phase control signal vP is VP<V.

Then, a deceleration signal is outputted to 516, and the motor is set to the rotational speed ω3 at the maximum deceleration at time t6. At this time, the rotation direction is also in reverse mode ()Iigh. Rotation speed Lo
After the ck signal becomes High, it is set to Low at t6.

Next, the motor is turned off at time t7. speed control signal V,
, f, phase control signal V, is %=OV<V3. Although VP=OV<V, the output of the inverter 16 becomes Low, so the deceleration signal from 516 is not output to S8 and 59. However, the brake signal S4 (High
h) is output. The motor rapidly decelerates due to the brake signal S4 and stops at time t8.

The rotation speed LOCK signal becomes the old 8h.

As mentioned above, by detecting the voltage change of the speed control signal when changing the rotation speed and outputting an acceleration signal or deceleration signal, it is possible to quickly change the rotation speed and significantly shorten the access time. It is. In addition, by setting the rotation speed Lock signal from the voltage change of the phase control signal, the rotation speed can be locked when the rotation speed error is within ±0.1%.
Since the signal can be output, it is possible to determine whether recording/reproducing is possible or not based on the rotation speed lock signal.

However, as shown in FIG. 2, the rotation speed lock signal may cause chattering due to the transient response waveform of the phase control signal. As a countermeasure, a low-pass filter is attached after the phase control signal S6, and then the comparators 14 and 1
5 can be done manually. By setting an appropriate cutoff frequency fc, it is possible to obtain a rotation speed lock signal that is free from chattering and has a good response.

A diagram showing a control drive circuit, Figure 2 is the timing diagram of Figure 1, Figure 3 is a diagram showing a conventional motor rotation speed control drive circuit; FIG. 4 is a timing diagram of FIG. 3.

[Effects of the Invention] As described above, according to the present invention, since the configuration is such that an acceleration signal or deceleration signal is generated by detecting a change in the speed control signal, it is possible to quickly and stably change the rotation speed. , fast access times can be achieved.

In addition, since the configuration is such that the rotation speed lock signal can be generated by detecting changes in the phase control signal, it is possible to detect the rotation speed lock with a rotation accuracy of about ±0.1%, for example.
It can be used as an effective judgment signal when entering the recording/playback mode.

1...Motor drive IC.

2...FG amplifier, 10...Servo control IC1 11...Presettable counter, 12, I3.14.15...Comparator, S4...
- Brake output, S5...speed control signal output, S6...phase control signal output, S8...control signal manually, S9...forward/reverse rotation signal input.

[Brief explanation of drawings]

Claims (1)

[Scope of Claims] 1) A DC motor rotation speed control device comprising: a frequency dividing circuit for switching the rotation speed; a circuit that generates an acceleration signal when transitioning from low speed rotation to high speed rotation; A motor rotation speed control device comprising: a circuit that generates a deceleration signal when the rotation speed is set; and a circuit that generates a rotation speed lock signal immediately after the rotation speed is established. 2) The motor rotation speed control device according to claim 1, wherein the frequency dividing circuit is comprised of a presettable counter. 3) The acceleration signal generation circuit compares the speed control signal and the reference voltage (V_4) and determines that the speed control signal voltage>the reference voltage (
2. The motor rotation speed control device according to claim 1, wherein the motor rotation speed control device generates an acceleration signal when V_4). 4) The deceleration signal generation circuit compares the speed control signal and the reference voltage (V_3) and determines that the speed control signal voltage<the reference voltage (V_3).
2. The motor rotation speed control device according to claim 1, wherein the motor rotation speed control device generates a deceleration signal when V_3). 5) The lock signal generation circuit compares the phase control signal with the reference voltages (V_1, V_2) and determines the reference voltage (V_2).
2. The motor rotation speed control device according to claim 1, wherein the rotation speed lock signal is generated when >phase control signal voltage>reference voltage (V_1).