KR19980058016A - Driving circuit of 3-phase unipolar head drum motor - Google Patents

Abstract

The present invention relates to a driving circuit of a three-phase unipolar head drum motor, which is connected to each other according to a three-phase wiring method set on the magnet coil of the head drum motor, and supplies a driving current to the magnet coils, respectively. And a hall sensor connected to the base end of the driving transistor to detect the rotational position of the head drum motor. The head drum motor is controlled by a simple circuit configuration, thereby simplifying the driving circuit. Since it is composed of a simple switching element, the manufacturing cost of the driving circuit can be significantly reduced accordingly.

Description

Driving circuit of 3-phase unipolar head drum motor

The present invention relates to a driving circuit of a three-phase unipolar head drum motor, and in particular, by simplifying the step of detecting the rotational position of the motor by eliminating the digital detection switching unit for detecting the position of the head drum motor. The present invention relates to a driving circuit of a three-phase unipolar head drum motor which can reduce manufacturing costs of the driving circuit accordingly.

In general, the VRC system has a very small dimension of recording a video signal, a track width of about 0.2-0.02 mm, a recording wavelength of about several microns, and is recorded in the tape width direction. Therefore, during recording and playback, it is necessary to perform stable control of the head drum rotation so as not to change as the time axis of the video signal increases. In addition, in order to maintain tracking of the video track, it is necessary to drive the head drum rotation and the tape running state (speed and position relationship) as in recording.

Then, referring to FIG. 1, the conventional driving circuit of the head drum motor of V-Cal as described above, the plurality of Hall sensors 71A-C detecting the rotational position of the head drum motor 70 of the V-C at a predetermined angle. A detection switch 72 connected to the output terminal of the Hall sensors 71A-C to switch the detection voltage, and an amplifier for amplifying the detection signal output from the detection switch 72 to a predetermined level. 73 and a drive control unit 75 connected via resistors R1-R3 to one end of the amplifier 73 to input driving currents to the magnet coils 74A-C of the head drum motor 70. )

In addition, the detection switch unit 72 is connected to an output terminal of the hall sensor 71A to output a detection switching signal, and a NAND gate 76, and the hall sensor 71B alternately switched with the hall sensor 71A. And a NAND gate 77 connected to the NAND gate 77 for outputting a detection switching signal, and a NAND gate 78 connected to the hall sensor 71C which is alternately switched with the hall sensor 71B, and outputting a detection switching signal. . In addition, an inverter 79 connected to the hall sensor 71C is connected to an input terminal of the NAND gate 76, and an inverter 80 connected to the hall sensor 71A is connected to an input terminal of the NAND gate 77. The inverter 81 connected to the hall sensor 71B is connected to an input terminal of the NAND gate 78.

In addition, the amplifying unit 73 is connected to the output terminal of the NAND gate 76 via a resistor R1 and a PNP type amplifying transistor 82 connected to the output terminal of the NAND gate 77 via a resistor R2. A PNP amplifying transistor 83 and a PNP amplifying transistor 84 connected via a resistor R3 to an output terminal of the NAND gate 78 are constituted.

In addition, a drive control transistor 85 is connected to the drive control unit 75 via a resistor R4 at one end of the amplifying transistor 82 to input a drive current to the magnet coil 74A of the head drum motor 70. And a driving control transistor 86 connected to one end of the amplifying transistor 83 via a resistor R5 to input a driving current to the magnet coil 74B of the head drum motor 70, and the amplifying transistor 84. It is composed of a drive control transistor 87 is connected via a resistor (R6) to one end of the input to drive the drive current to the magnet coil (74C) of the head drum motor (70).

In addition, a bias power source E is connected to the emitter terminals of the amplifying transistors 82 to 84.

Here, the amplifiers 82-84 are constituted by PNP transistors.

Meanwhile, referring to the operation of the conventional head drum motor driving circuit having the above configuration, first, when the play mode or the recording mode signal is input to the V-C, an arbitrary detection voltage is applied to the hall sensor 71A during the first driving. I will let you. Then, the hall sensor 71A inputs a detection signal according to the detection voltage, for example, a high signal to the NAND gate 76 of the detection switching unit 72. The detection voltage of the hall sensor 71A is an inverter. The 80 is inverted to a low signal and input to the NAND gate 77.

At this time, since the other Hall sensors 71B and 71C do not perform a detection operation, a detection signal is input to the NAND gates 77 and 78, for example, and the low signal of the Hall sensor 71C is an inverter. It is inverted via 79 and then input to the NAND gate 77.

Therefore, since both signals are input to the NAND gate 77, the low signal is outputted to the amplifying transistor 82 of the amplifier 73 via the resistor R1. Then, the amplifying transistor 82 composed of the PNP type transistor is turned on according to the low signal of the NAND gate 76 to input the amplified detection signal to the base terminal of the driving transistor 85 via the resistor R4. This drive transistor 85 is then turned on. Accordingly, the bias power source E flows through the magnet coil 74A of the drum motor 70 to the driving transistor 85 and thus magnetic flux is generated in the magnet coil 74A of the drum motor 70. (Not shown) will attract the magnetic poles of the drum motor 70 is rotated by a predetermined rotation angle. On the other hand, when the drum motor 70 is rotated as in the above process, the detection switching unit 72 is operated in contrast to the above process, so that magnetic flux is generated in the magnet coil 74B of the drum motor 70. Will rotate.

When the hall sensors H1-3 perform the detection operation as described above, the NAND gates 76-78 of the detection switch unit 72 are switched to switch the magnets of the drum motor 1. Since the driving power is sequentially applied to the coils 74A-C, the drum motor 1 continuously rotates, and accordingly, the head drum (not shown) interlocked with the drum motor 1 also rotates. The head mounted on the back of the video tape to play or record information.

However, the driving circuit of the conventional head drum motor as described above is composed of digital devices, such as NAND gates 76-78 or inverters 79-81, in which the components constituting the detection switching unit 72 are relatively expensive. As a result, the manufacturing cost of the driving circuit which must be installed has increased considerably, and since the detection switching unit 72 is composed of a complicated circuit, there is a disadvantage in that the complexity of the component circuit is increased accordingly.

Accordingly, the present invention has been made to solve the above-mentioned disadvantages, simplifying the switching position detection circuit by simplifying the step of detecting the rotational position of the motor by removing the digital detection switching unit for detecting the position of the head drum motor. Accordingly, the object of the present invention is to provide a driving circuit of a three-phase unipolar head drum motor which can reduce the manufacturing cost of the driving circuit.

The present invention for achieving the above object is a drive transistor which is connected in accordance with the three-phase connection method set to the magnet coil of the head drum motor, respectively supplying a drive current to the magnet coil, and the drive transistor It is characterized in that the hall sensor is connected to each of the base end for detecting the rotation position of the head drum motor.

1 is an explanatory diagram illustrating a driving circuit of a conventional head drum motor.

2 is an explanatory diagram illustrating a head drum motor to which the present invention is applied;

3 is a circuit diagram illustrating a circuit of the present invention.

Explanation of symbols on the main parts of the drawing

1: Head drum motor 2: Rotor

3: stator 4: head drum

5: fixed printed circuit board 6a-n: magnet coil

7: core 8: stimulation

9a-c: Drive transistor 10: Microcomputer

H1-3: Hall sensor R1-4: Resistance

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention is applied to a driving circuit for driving a head drum motor. First, the head drum motor 1 will be described with reference to FIG. 2. The head drum motor 1 has a large rotor 2 and a stator 3. It will consist of. At this time, the stator 3 is installed in the form of a core 7 wound with a magnet coil 6a-n on a fixed printed circuit board 5 installed below the head drum 4, and the stator 3 In the opposite position, a rotor 2 having a plurality of magnets of N and S poles magnetized on the inner surface of the rotating cylinder with a predetermined gap is installed.

And, as shown in Fig. 3, the design circuit is connected to each other according to the three-phase wiring method set on the magnet coils 6a-c of the head drum motor 1, and the magnet coils 6a- are connected. c) Hall transistors 9a-c for respectively supplying a drive current to the drive current; and Hall sensors H1-3 connected to the base ends of the drive transistors 9a-c to detect the rotational position of the head drum motor 1, respectively. ).

In addition, a bias power source E is connected to emitter terminals of the driving transistors 9a to c, and resistors R1-3 are connected to ground terminals at one end of each hall sensor H1-3. The bias power source E is connected to the other input terminals of the hall sensor H1-3 via a resistor R4.

Here, the driving transistors 9a-c are formed of PNP transistors, and magnet coils 6a-c are connected to the collector terminals of the driving transistors 9a-c by star connection.

Next, the operation of the present invention having the above configuration will be described.

In the circuit of the present invention, as shown in FIGS. 2 and 3, when the play mode or the recording mode signal is input to the V-CAL, the microcomputer 10 drives the head drum motor 1, in which random detection is performed during the first driving. The voltage is applied to the Hall sensor H1. Then, the Hall sensor H1 inputs a detection signal to the base end of the driving transistor 9a according to the detection voltage, and this detection voltage is applied to the base end of the driving transistor 9a as a low signal. . Then, the driving transistor 9a is turned on in response to the low signal of the hall sensor H1, and accordingly, the driving voltage E is applied to the head drum motor 1 through the emitter terminal and the collector terminal of the driving transistor 9a. The magnetic flux is generated in the magnet coil 6a because the magnet coil 6a flows to the magnet coil 6a, thereby rotating the rotor 2 by a predetermined rotational angle. At this time, the magnet coils 6b and 6c of the other phases do not operate because the driving transistors 9b and 9c are not turned on.

On the other hand, when the magnet coil 6a is driven according to the above process and the rotor 2 of the head drum motor 1 rotates by a predetermined rotation angle, the hall sensor H2 of the next phase becomes the rotor 2. ) Detects the rotation position and outputs a detection signal, for example, a low signal. At this time, the hall sensor H2 inputs the low signal to the base end of the driving transistor 9b. Then, the driving transistor 9b is turned on according to the low signal of the hall sensor H2, and accordingly, the driving voltage E is applied to the head drum motor 1 through the emitter terminal and the collector terminal of the driving transistor 9b. The magnetic flux is generated in the magnet coil 6b because the magnet coil 6b flows to the magnet coil 6b, thereby rotating the rotor 2 by a predetermined rotational angle. At this time, the magnet coils 6a and 6c of the different phases do not operate because the driving transistors 9a and 9c are not turned on.

In addition, when the magnet coil 6c is driven in accordance with the above process and the rotor 2 of the head drum motor 1 rotates by a predetermined rotation angle, the hall sensor H3 of another next phase is rotated. By detecting the rotational position of (2), a detection signal is outputted, for example, a low signal. At this time, the hall sensor H3 inputs the low signal to the base end of the driving transistor 9c. Then, the driving transistor 9c is turned on in response to the low signal of the hall sensor H3, and accordingly, the driving voltage E is applied to the head drum motor 1 through the emitter terminal and the collector terminal of the driving transistor 9c. The magnetic flux is generated in the magnet coil 6b because the magnet coil 6b flows to the magnet coil 6b, thereby rotating the rotor 2 by a predetermined rotational angle. At this time, the magnet coils 6a and 6b of different phases do not operate because the driving transistors 9a and 9b are not turned on.

Therefore, if this process is repeated, the drum motor 1 continuously rotates, and accordingly, the head drum 4 interlocked with the drum motor 1 also rotates, so that the head mounted on the head drum 4 becomes a video. Information is played back or recorded from tape.

As described above, the present invention simplifies the switching position driving circuit by eliminating the digital detection switching unit for detecting the position of the head drum motor, thereby simplifying the switching driving circuit, thereby reducing the manufacturing cost of the driving circuit. There is an effect that can be reduced.

Claims (1)

In the driving circuit of the head drum motor for controlling the driving of the head drum motor 1 having the magnet coils 6a-n, Drive transistors 9a- which are connected to the magnet coils 6a-c of the head drum motor 1 in accordance with a three-phase connection method to supply driving currents to the magnet coils 6a-c, respectively. c) and a Hall sensor (H1-3) connected to the base ends of the drive transistors (9a-c) for detecting the rotational position of the head drum motor (1), respectively. The driving circuit of the drum motor.