KR0170961B1 - Apparatus for driving a drum motor for use in a vcr - Google Patents

Abstract

The present invention relates to a drum motor driving apparatus of V. C. R, wherein the magnetic flux is induced by the power supply unit (Vcc) for supplying the driving power of the drum motor 10 and the power supplied from the power supply unit (Vcc). Connected to the coil L, the power supply Vcc, and the switching flow element 7, and when a switching current is applied from the switching hall element 7, it is turned on to supply the power supply Vcc. Switching unit (S) consisting of SCR (semiconductor controlled rectifier) for providing the power supplied from the coil (L), and when the switching unit (S) is turned off (Off-Off) due to the back EMF remaining in the coil It is configured to include a current-emitting portion Df composed of a diode for emitting a current i _Dlf .

Therefore, the present invention can simplify the circuit configuration and reduce the manufacturing cost of V.C. By eliminating the current caused by the counter electromotive force, it is possible to improve the uniformity of the rotation of the motor.

Description

VC's drum motor drive

1 is a cross-sectional view of a drum motor used in a conventional V.C. egg.

2 is a circuit diagram of a conventional V. C. drum motor drive device.

Third, V. according to the present invention. Seed. Circuit diagram of egg's drum motor drive.

4 shows a V according to the invention shown in FIG. Seed. A diagram for explaining the flow of electric current in a circuit diagram of an egg drum motor driving apparatus.

* Explanation of symbols for main parts of the drawings

1: rotor case 2: magnet

3, L: Coil for driving 4: Stator core

5: printed circuit board 6: rotating shaft

7,100,200: Switching Hall element Q: Transistor

R: Resistance Vcc, -Vcc: Power

Df: Diode S: SCR

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a drum motor driving apparatus for a video cassette recorder (hereinafter abbreviated as V. C. Al.), And in particular, a V that can simplify the circuit configuration and improve the uniformity of rotation. Seed. It relates to an egg drum motor driving apparatus.

Typically, a recording and playback head is used to perform functions such as recording and playback in a V.C. egg. By the way, such a recording and reproducing head is mounted on a drum, and this drum is commonly called a head drum.

On the other hand, when V.C.R is in the recording and reproducing mode, the drum on which the reproducing and recording head is mounted rotates at a predetermined speed so that playback can be performed from the cassette tape proceeding at a constant speed or recording to the cassette tape. do.

In addition, a drum motor is generally used as a device for driving the head drum. A drum motor is generally divided into two parts, a stator and a rotor. Magnets are mounted on the inside and the bottom of the rotor, and a predetermined number of pulse generators and circuits generate pulses according to the rotation of the coil and the rotor. It is equipped with a switching Hall element for providing rotational force to the electron.

1 is a cross-sectional view showing a conventional V. C. drum motor.

As shown in FIG. 1, a conventional V. C. drum motor includes a rotor case (1), a magnet (2), a stator core (4), a driving coil (3), and a printed circuit board. and includes a circuit board (PCB), a rotating shaft 6, and a switching hall element 7.

On the other hand, the driving of the drum motor is briefly described as follows.

The Hall effect occurs in the two switching Hall elements 7 under the influence of the magnetic field formed in the magnet 2, whereby a voltage is induced in the Hall element 7. Then, the induced voltage is applied to the driving coil 3, and thus, the magnet 2 is rotated by moving the magnet 2 by the change of the magnetic flux induced by the driving coil 3 to drive the drum motor. Done.

2 is a circuit diagram of a conventional conventional V. C. drum motor driving apparatus, which is disclosed in Korean Patent No. 95-28112 filed by the present inventors on August 31, 1995

Also, the conventional V shown in FIG. Seed. The drum motor driving device of an egg is a rotor case of the drum drum motor of an V drum motor of an V drum driving device for driving a drum motor for rotating the head drum of the VC egg. According to the polarity of the magnet mounted on the inner surface, the first and second switching flow elements alternately generating positive and negative voltages, and the first switching flow element are connected to each other, so that the positive voltage is A first transistor that is turned off when it occurs, a third transistor that is connected in parallel with the first transistor and turned on when a positive voltage occurs in the first switching hall device; A fourth transistor connected to the second switching flow element and turned off when a positive voltage is generated in the second switching hole element, and a second switching hole connected in parallel with the fourth transistor; Positive charge in the device A sixth transistor turned on when the voltage occurs. A first power supply for supplying positive power, a second power supply for supplying negative power, and being connected to the first power supply and the first transistor to be turned on when the first transistor is turned off A fifth transistor connected to a second transistor, the second power supply and the fourth transistor, and turned on when the fourth transistor is turned off; and between the second transistor and the collector terminal of the fifth transistor. And a first coil and a second coil connected in parallel to each other to induce magnetic flux according to a power supplied from the first or second power supply when the second transistor or the fifth transistor is turned on.

Looking at the operation of the conventional V. C. drum motor drive device configured as described above are as follows.

When a positive voltage is induced in the first switching hall element 100, the voltage is applied to the transistors Q1 and Q3 through the input terminal A and the resistor R5. Accordingly, transistor Q1, which is a pnp type transistor, is turned off and transistor Q3, which is an npn type transistor, is turned on.

The transistor Q2 is turned on by the voltage difference between the base terminal and the emitter terminal, and the supply power of the first power supply Vcc is connected in parallel to each other through the turned-on transistor Q2 and in the opposite direction. The current flows through the wound first and second coils La and Lb.

Accordingly, magnetic fluxes φa and φb in opposite directions are formed in the first and second coils La. Lb, and the magnetic fluxes φa and φb become driving forces for rotating the drum motor. The current passing through the first and second coils La and Lb flows through the transistor Q3.

On the other hand, at this time, that is, when a positive voltage is induced in the first switching hall element 100, a negative voltage is generated in the second switching hall element 200 to generate an input terminal B and a resistor R6. Is applied to the transistor Q4 and the transistor Q6. However, since the transistor Q4 is of the pnp type, it is turned on by the applied voltage, and the transistor Q6 is turned off because of the npn type. Accordingly, a closed loop is formed in the second power supply unit -Vcc and the transistor Q4, and the supply power of the second power supply unit -Vcc is the first and second coils La and Lb. ) Will not be affected.

Also. On the contrary, when a negative voltage is induced in the first switching flow element 100 and a positive voltage is induced in the second switching hole element, the power supplied from the first power supply unit Vcc is the same as described above. And the second coil is not affected, and the magnetic flux is induced in the first and second coils La and Lb by the power of the second power supply unit (-Vcc), and the induced magnetic flux is the first switching hole. The magnetic flux is formed in a direction opposite to the directions of the magnetic flux? A and? B induced by the element 100 and the first power supply Vcc.

That is, since the winding directions of the first and second coils La and Lt are opposite to each other, magnetic fluxes are induced in opposite directions, and the magnetic fluxes simultaneously give a driving force to the rotating magnet 2 to rotate the drum motor. do.

However, the conventional V.C.R drum motor driving apparatus as described above has a somewhat uneven rotation due to the counter electromotive force remaining in the coil, and uses a large number of power transistors to supply a large current. In addition, since the price of power transistors is high, there is a problem of increasing the manufacturing cost of V.C.R.

Therefore, the present invention has been proposed to solve such a problem, and an object of the present invention is to simplify the circuit configuration of the drum motor driving apparatus, thereby reducing the manufacturing cost, and also eliminating the residual counter electromotive force to more uniformly rotate the drum motor. To provide V. C. R. drum motor drive.

According to a preferred embodiment of the present invention for achieving the above object, according to the polarity of the magnet mounted on the inner surface of the rotor case of the drum motor for driving the drum motor for rotating the head drum of V.C. A V including a switching flow element that alternately generates positive and negative voltages that are induced. Seed. An egg drum motor driving apparatus comprising: a power supply unit for supplying power for driving the V.C.al drum motor, a coil for inducing a predetermined magnetic flux by a power source provided from the power supply unit, and A switching unit which is connected to a power supply unit and the switching hall element and is turned on when the switching current is supplied from the switching hall element to provide power supplied from the power supply unit to the coil, and the switching unit When turned off (offed) is configured to include a current discharge unit for releasing the current by the back electromotive force accumulated in the coil.

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

3 is a circuit diagram of a V. C. drum motor driving apparatus according to a preferred embodiment of the present invention.

As shown in FIG. 3, the present invention provides a power supply unit Vcc for supplying driving power of the drum motor 10 and a coil L for inducing magnetic flux according to the power supplied from the power supply unit Vcc. And a power source connected to the power supply unit Vcc and the switching hall element 7 and turned on when a switching current is applied from the switching flow element 7 to be provided from the power supply unit Vcc. And a switching unit 5 composed of a semiconductor controlled rectifier (SCR) for providing the coil L, and a current i _Df due to the counter electromotive force remaining in the coil when the switching unit 5 is turned off. And a current discharge unit (Df) composed of a diode for emitting ().

Referring to the operation of the present invention configured as described above are as follows.

As shown in FIG. The switching part, i.e., the anode terminal of the SCR 5, is connected to the power supply Vcc, and the gate terminal A is connected to the switching hall element 7, and the gate terminal A is It becomes a switching current input terminal of the switching hall element 7.

When a switching current is applied from the switching hall element 7 to the gate terminal A of the SCR (S), the SCR 5 is turned on, whereby the power supply of the power supply Vcc is the resistor R Is supplied to the coil L to induce magnetic flux, and the magnetic flux induced in the coil L becomes an electromotive force for driving the motor 10.

At this time, since the diode Df is reverse to the current direction provided from the power supply Vcc, the current i1 is provided to the coil L via the resistor R.

On the other hand, if no switching current is supplied from the switching hall element 7 to the gate terminal A, the SCR 5 is turned off, and the power from the power supply Vcc is not provided to the coil L. At this time, the current due to the counter electromotive force generated by the magnetic flux induced in the coil L at the time of turn-on of the SCR 5 is discharged through the diode Df.

Therefore, a switching current is applied to the gate terminal A next, and the SCR 5 is turned on, thereby acting in the opposite direction to the magnetic flux induced by the coil L, thereby preventing normal driving of the motor 10. It is possible to release the residual current.

As a result, the diode Df is used as a free-wheeling diode that emits a residual current due to counter electromotive force, thereby improving uniformity of rotation of the drum motor 10.

That is, as shown in FIG. 4, when SCR (S) is turned on, the same current i2 as current i1 enters into coil L to induce magnetic flux in coil L, and SCR ( When S) is turned off, current (i _Df ) flows out of coil (L) to remove residual magnetic flux caused by counter electromotive force.

Therefore, the present invention constitutes a drum motor driving apparatus using SCR, so that the circuit configuration can be simplified. The manufacturing cost of the C. egg can be lowered and the uniformity of the rotation of the motor can be improved by removing the current caused by the counter electromotive force.

While the invention has been shown and described with respect to certain preferred embodiments, those skilled in the art will recognize that various modifications and changes can be made without departing from the spirit and scope of the invention as set forth in the claims below.

Claims (3)

To drive the drum motor 10 that rotates the head drum of the V.C. egg, the amount of induced voltage and the voltage of the magnetized in accordance with the polarity of the magnet 2 mounted on the inner surface of the rotor case 1 of the drum motor In the V.C.R.m drum motor driving device including the alternating switching Hall elements (7), a power supply unit (Vcc) for supplying power for driving the V.C.R.m. drum motor (10). And the coil L for inducing a predetermined magnetic flux by the power supplied from the power supply Vcc, the power supply Vcc, and the switching hall element 7, 7 is switched on when the switching current is supplied from the switching unit (S) for providing the power supplied from the power supply (Vcc) to the coil (L) and the switching unit (S) When is turned off, the current due to the counter electromotive force accumulated in the coil 5 is emitted. V. Mr. Al of the drum motor drive unit comprising a current-emitting region (Df) to turn on. The apparatus of claim 1, wherein the switching unit (S) is a SCR (semiconductor controlled rectifier). The apparatus of claim 1, wherein the current discharge unit (Df) is a free-wheeling diode.