JPH0724476B2 - Motor control circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control circuit, and in particular, generates a reverse rotation torque in response to a brake command signal to apply a braking force to the motor, thereby stopping the motor. The present invention relates to a motor control circuit that determines whether or not there is a motor based on the rotation speed of the motor.

[Prior art]

Generally, in a motor control circuit of this kind, when a brake command signal is given, the polarity of the drive torque of the motor is reversed to generate a braking force by the reverse rotation torque, the stop state of the motor is detected, and the motor is stopped. If so, the reverse rotation torque is released to stop the motor by the reverse rotation torque brake.

[Problems to be solved by the invention]

In the conventional circuit, the motor stop detection operation described above is a method of detecting when the number of rotations of the motor becomes a certain value or less (stop mode) or when the rotation direction becomes (reverse rotation mode). , In either case, the stop cannot be detected unless the motor rotates even slightly.

In the conventional circuit, even when both the device and the motor are stopped, the brake command signal is input and the device is started by turning on the power as it is, the device follows the procedure from to. Operate. Therefore, the stop cannot be detected unless the motor is once rotated. Therefore, the motor is momentarily rotated, and it is not preferable in terms of reliable stopping by the brake.

In particular, assuming that the motor is used as a drive device for a floppy disk, for example, the motor or disk will rotate just by starting the device before driving the motor or disk, which will not only annoy the user. The problem arises that the stop position of the floppy disk shifts.

Therefore, a primary object of the present invention is to provide a motor control circuit that does not undesirably rotate the motor when starting the device.

[Means for solving problems]

This invention is a drive circuit (12) for driving a motor (14).
Rotation direction detecting means (38) and drive control means (40, 2
8), stop detection means (36), brake command signal detection means (58), first drive circuit off means (52), second
And a third drive circuit OFF means (54) and a third drive circuit OFF means (54), wherein the rotation direction detecting means (38) is provided when the motor (14) rotates. The generated rotation signal is applied and a rotation direction detection signal indicating the rotation direction of the motor (14) is output. The drive control means (40, 28) instructs the rotation direction detection signal and the braking of the motor (14). And a forward / reverse command signal for instructing the rotation direction of the motor (14) are applied, and a drive signal corresponding to each state of the rotation direction detection signal, the brake command signal and the forward / reverse command signal is output. While controlling the drive circuit (12), it outputs a determination signal for determining whether or not the drive control means (40, 28) operates normally, and the stop detection means (36) outputs a brake command signal and The rotation signal is applied and the brake command signal is When a rotation signal is generated and the rotation signal disappears, a stop signal indicating that the motor has stopped is output, and brake command signal detection means (58)
Applies a brake command signal and outputs a drive-off signal only during a period when the brake command signal is applied when the motor (14) is started. The first drive circuit-off means (5
2) operates in response to the determination signal indicating that the drive control means (40, 28) is not operating normally, and disconnects the current path of the drive circuit (12) to drive the drive circuit. (12)
For turning off the second drive circuit off means (56)
Is a circuit for turning off the drive circuit (12) by shutting off the current path of the drive circuit (12) when the stop signal is applied, and the third drive circuit off means (54) receives the drive off signal. , The current path of the drive circuit (12) is cut off only during the period when the brake command signal is applied when the motor (14) is started.
This is a motor control circuit that turns off 2) and prevents the motor from causing undesired rotation when the motor is started.

[Action]

A torque is applied to the motor according to the rotation direction commanded by the drive circuit, and the motor is rotationally driven in that direction. When the brake command signal is given during the rotation of the motor, the drive control means operates the drive circuit so that the torque applied to the motor has a reverse polarity, for example.

When the motor approaches the stop according to the braking force and the number of revolutions becomes a certain value or less, the stop detection means detects that the motor has stopped. When the stop detection means detects the stop of the motor, the second drive circuit OFF means operates to release the braking force by the drive circuit means.

On the other hand, at the time of start-up, if the brake command signal is input, the drive circuit is turned off by the third drive circuit off means, so the drive torque is not applied to the motor and the motor does not rotate.

When the brake command signal is released, for example, the one-way RS flip-flop is brought into the first state, so that the third drive circuit OFF means and the normal operation can be performed without operating.

〔The invention's effect〕

According to the present invention, since the drive circuit is disabled by the start detecting means and the third drive circuit turning off means when the brake command signal is given at the time of starting, the motor is not desired at the time of starting like the conventional circuit. There is no problem that it will rotate to.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention. The motor control circuit 10 includes a driving circuit 12, the driving circuit 12 includes a plurality of transistors 12 _U1 to 12 _W4. The drive circuit 12 _{supplies a} drive voltage to the motor 14 by sequentially turning on these transistors 12 _{U1 to} 12 _W4 to control the rotation direction and the rotation speed of the motor 14.

The rotation direction and the number of rotations of the motor 14 are, for example, Hall ICs.
It is detected by magnetic sensors 16 to 20 composed of, for example. The magnetic sensors 16 to 20 detect the rotational direction by detecting the magnetic flux of the permanent magnet embedded in the rotor of the motor 14, for example, and the rotational speed by detecting how many times per unit time. Since the detection signals from the magnetic sensors 16 to 20 are weak, they are amplified by the amplifiers 22 to 26, respectively.

The amplified detection signals from the magnetic sensors 16 to 20 are output to the motor.
It is input to the matrix circuit 28 as a feedback signal for controlling the rotation speed of 14. Also a magnetic sensor
The amplified signals of 16 to 20 are respectively shaped by the waveform shapers 30 to 34, and then input to the stop detection circuit 36.

The outputs of the two waveform shapers 30 and 32 are applied to the data terminal D and the clock terminal CL of a D-type flip-flop (hereinafter referred to as "D-FF") 38, respectively. D-FF
38 is the magnetic sensor 16 and when the motor 14 is rotating.
By alternately detecting the magnetic flux by 18 and alternately outputting signals from the waveform shapers 30 and 32, it is detected in which direction the motor 14 is rotating. For example, if there is a "0" signal from the magnetic sensor 18 first,
In the D-FF38, since "0" is input to the clock terminal CL when the data terminal D is "1", the output terminal Q
"1" is output to. On the contrary, if the magnetic sensor 16 first outputs a signal and then there is a signal from the magnetic sensor 18, D
-FF38 is a clock terminal when the data terminal D is "0".
Since "0" is input to CL, "0" is output to the output terminal Q. In this way, the D-FF 38 detects in which direction the motor 14 is currently rotating.

The output terminal Q of the D-FF 38 is connected to the input of the forward / reverse controller 40. Therefore, the forward / reverse controller 40 is provided with "1" or "0" representing the current rotation direction of the motor 14.

The forward / reverse controller 40 is supplied with a brake command signal B and a forward / reverse command signal F / R from a device control system (not shown) such as a microcomputer. The brake command signal B is given as "1" when applying a braking force to the rotating motor 14 and as "0" during normal rotation. The forward / reverse command signal F / R is given as "1" when designating rotation in the forward direction and "0" when designating rotation in the reverse direction.

The forward / reverse controller 40 indicates the direction of rotation of the motor 14 based on the rotation direction signal of the motor 14, the brake command signal B, and the forward / reverse command signal F / R. A setting signal is output, and this rotation direction setting signal is given to the input terminal F of the matrix rotation 28, inverted by the inverter 42, and given to the input terminal R of the same matrix circuit 28. For example, the forward / reverse controller 40 issues an instruction to reverse the rotation direction of the matrix circuit 28 when the brake command signal B changes to "1" and when the forward / reverse command signal F / R is reversed. Output to the input terminals F and R.

From the terminals U to W of the matrix circuit 28, the motor 14 is moved in the direction according to the rotation direction setting signal from the forward / reverse controller 40.
In order to form a rotating magnetic field by its windings so as to rotate, pulses or phase difference signals each having a phase difference of 120 ° are output. For example, when the motor 14 is rotated in the forward direction, the phase difference signals are output from the terminals U to W in the order of U → V → W. When rotating in the reverse direction, the phase difference signals are output from the matrix circuit 28 in the order of W → V → U. In this way, the matrix circuit 28
Whenever a phase difference signal is output from, a predetermined transistor is turned on each time and a current from the constant current source 44 flows in,
A rotating magnetic field is generated in the Y-connected winding of the motor 14.

The emitters of the three transistors 12 _{U2 to} 12 _W2 of the drive circuit 12 are commonly connected to the collector of the transistor 46 whose emitters are grounded. The base of transistor 46, together with transistors 52, 54 and 56, is the output of the AND circuit.
Together with the collector and the base of the transistor 48 constituting the above, the collectors of the transistors 52 to 56 are commonly connected. When the transistor 46 is off, the collector current paths of the transistors 12 _{U2 to} 12 _W2 are cut off, and the drive circuit 12 as a whole is turned off or disabled. On the other hand, when transistor 46 is on, transistor 12
_Since a collector current path of _{U2 to} 12 _W2 is formed, the motor
14 drives are possible.

The comparator 50 compares the drive torque generated by the motor 14 with a torque command signal from a microcomputer (not shown) and changes the collector current of the transistor 46 to control the torque.

The base of one transistor 52 forming the above-mentioned AND circuit is connected to the output terminal of the forward / reverse controller 40. From this output terminal, when the forward / reverse controller 40 is operating normally, that is, regardless of whether the forward rotation or the reverse rotation is instructed,
"0" is output.

The base of the transistor 54 is connected to the output terminal Q of a one-way stable RS flip-flop (hereinafter simply referred to as “RS-FF”) 58. The reset terminal R of RS-FF58 is always kept at "1", and the brake command signal B is set to the set terminal S.
Is given. Therefore, the RS-FF 58 sets the output terminal Q to "1" only when the brake command signal B is given as "1" at the time of starting.

Here, the specific circuit of the RS-FF58 will be described with reference to FIG. RS-FF58 has 2 characteristics with good matching.
It is formed by one transistor 60 and 62, four resistors 64-70 and a level shift diode 72. The resistance value of each of the resistances 64 to 70 is the resistance 64 = resistance 66, resistance
It is set to the relationship of 68 = resistance 70. The base of the transistor 62 is configured as the set input terminal S, and the base of the transistor 60 is configured as the reset input terminal R. The output terminal Q is drawn from the collector of the transistor 60, and the output terminal is drawn from the collector of the transistor 62.

The power supply Vcc is applied to the base of the transistor 62, that is, the set input terminal S through resistors 64 and 68, and the power supply Vcc is applied to the base of the transistor 60, that is, the reset input terminal R through resistors 66 and 70 and the diode 72.
Is applied. Therefore, the set input terminal S is "0".
In case of, the reset input terminal R is set to "1" by the power supply Vcc.
Therefore, the output terminal Q is "0" and the output terminal is "1".
Becomes Then, the brake command signal B is "1" at the time of startup.
Given, both the set input terminal S and the reset input terminal R become "1", the output terminal Q becomes "1", and the output terminal becomes "0", which stabilizes.

The base of the remaining transistor 56 forming the AND circuit is connected to the output terminal of the stop detection circuit 36. In the stop detection circuit 36, the brake command signal B is "1" as described above.
When it is detected that the motor 14 is stopped at, the output terminal outputs "1". At this time, the transistor 56 is turned on.

When any one of the transistors 52 to 56 described above is in the on state, the bases of the transistors 46 and 48 are at the low level, so that the transistor 46 is in the off state. Also, if all transistors 52-56 are in the off state, transistor 48 is on, and the base of transistor 46 will therefore carry current from the constant current source associated with comparator 50, thus turning transistor 46 on. Becomes As described above, the drive circuit 12 is activated (on) or disabled (off) by turning on or off the transistor 46.

In operation, when the device is started, the brake command signal B, that is, the set input terminal S of RS-FF58 becomes "1" when the power is turned on. On the other hand, as mentioned above, the RS-FF
The reset input terminal R of 58 is always "1" by the power supply Vcc.
Is. Therefore, the output terminal Q of the RS-FF58 becomes "1" and the output terminal becomes "0" and becomes stable.

When the output terminal Q of RS-FF58 is "1", the transistor 54
Turns on and therefore transistor 46 turns off. Therefore, the operation of the drive circuit 12 is stopped and the motor 14 does not rotate.

After that, when the brake command signal B is released and becomes "0", the set input terminal S of the RS-FF58 becomes "0" and the reset input terminal R remains "1". Therefore, the output terminal Q
Is "0" and the output terminal is "1". Therefore, transistor 54 can be turned off, transistor 46 can be turned on, and drive rotation 12 can also be activated.

After that, in RS-FF58, the reset input terminal R is always "1".
Therefore, by the action of the level shift diode 72, the state in which the output terminal Q is "0" and the output terminal is "1" is held regardless of "1" or "0" of the brake command signal B.

Since the other operation modes of this embodiment are the same as those of the conventional one, detailed description thereof will be omitted.

In this way, when the brake command signal B is given at the time of starting the device, the motor 14 whose drive rotation 12 is turned off does not rotate at all. Therefore, according to this embodiment, the motor does not operate at the time of starting the device. The problem of producing the desired rotation does not occur.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. FIG. 2 is a concrete circuit diagram showing an example of RS-FF in the embodiment of FIG. In the figure, 12 is a drive circuit, 14 is a motor, 36 is a stop detection circuit, 46, 48 and 52 to 56 are transistors, and 58 is RS-FF.
Indicates.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Yasohara 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Hiromitsu Nakano 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56) Bibliography Sho 58-127456 (JP, U)

Claims (2)

[Claims] 1. A drive circuit (12) for driving a motor (14)
Rotation direction detecting means (38) and drive control means (40, 2
8), stop detection means (36), brake command signal detection means (58), first drive circuit off means (52), second
And a third drive circuit off means (54), wherein the rotation direction detection means (38) rotates the motor (14). A rotation signal generated at any time is applied, and a rotation direction detection signal representing the rotation direction of the motor (14) is output. The drive control means (40, 28) includes the rotation direction detection signal and the motor ( 14) A brake command signal for instructing braking and a forward / reverse command signal for instructing the rotation direction of the motor (14) are applied, and each of the rotation direction detection signal, the brake command signal and the forward / reverse command signal A drive signal corresponding to the state is output to control the drive circuit (12), and a drive signal for determining whether the drive control means (40, 28) normally operates is output. The stop detecting means (36) is A rake command signal and the rotation signal are applied, and when the brake command signal is generated and the rotation signal disappears, a stop signal indicating that the motor has stopped is output, and the brake command signal detection means. (58) is for outputting the drive off signal only during a period when the brake command signal is applied and the brake command signal is applied when the motor (14) is started. The first drive circuit off means (58) 52) operates in response to the discrimination signal indicating that the drive control means (40, 28) is not operating normally when the discrimination signal is applied, and shuts off the current path of the drive circuit (12). Then the drive circuit (12)
The second drive circuit turning-off means (56) turns off the drive circuit (12) by applying the stop signal and cutting off the current path of the drive circuit (12). The third drive circuit turning-off means (54) applies the drive off signal to the current of the drive circuit (12) only during the period when the brake command signal is applied when the motor (14) is started. A motor control circuit for shutting off a path to turn off the drive circuit (12) to prevent the motor from causing an undesired rotation when the motor is started. 2. The brake command signal detecting means is in a first state regardless of the brake command signal in a steady state in which the motor (14) rotates, and the brake command signal is activated when the motor is started. One-way RS flip-flop (58) that enters the second state in response to a signal
The motor control circuit according to claim 1, wherein the motor control circuit comprises: