KR940000257B1 - Loading motor driving device - Google Patents

Abstract

The circuit includes a tape-regenerating unit for inputting the key-input or sensor signal, a microcomputer for generating the signals (forward or reverse rotation signal) according to the input signals of key-input or sensor signal, loading motor driving transistors (Q1,Q2) for applying power to the motor by the control signal of the microcomputer, and current control transistors (Q3,Q4) for controlling the direction of motor revolution by the control signal of the microcomputer. This method improves the driving efficiency of the loading motor.

Description

Loading motor drive circuit

1 is a circuit diagram for driving a loading motor of a video cassette recorder according to the prior art.

2 is a schematic block diagram of a video cassette recorder having a loading motor driving circuit according to the present invention.

3 is a detailed view of the loading motor driving circuit according to the present invention shown in FIG.

4 is a control flowchart of a microcomputer usable for this invention.

* Explanation of symbols for main parts of the drawings

1: key matrix 2: microcomputer

3: various sensors 4: control circuit

5: deck portion 6: loading motor driving circuit

Q1, Q2: Motor driving transistor Q3, Q4: Current control transistor

M: Loading Motor

The present invention relates to a circuit for driving a tape traveling system and a loading system as a single motor in a video cassette recorder, and more particularly, to fast forward (FF), rewind (REW), and play back a tape using only a plurality of transistors. A loading motor drive circuit for efficiently driving a loading motor for recording / stopping.

The video cassette recorder drives a loading system for driving a tape in a tape cassette to record information on the tape or to reproduce information recorded on the tape. A capstan motor that drives a loading motor and a tape reel (supply reel and take-up reel) is required. Currently, only one motor (hereinafter referred to as a loading motor) is used to drive both the loading system and the odometer. In order to drive the motor, a dedicated integrated circuit IC1 for driving a loading motor as shown in FIG. 1 was used. That is, the loading motor driving integrated circuit IC1 includes a plurality of input / output terminals ① to ⑩, and the control signals F and R from the microcomputer (not shown) are applied to the terminals ⑤ and ⑥. It was. Therefore, the loading motor M is capable of forward and reverse rotation by the state of the control signals F and R, and is driven by the control signals F and R input to the loading motor driving integrated circuit IC1. Table 1 shows the state of the loading motor (M) to be as follows.

TABLE 1

However, in the case of using the integrated motor IC1 for driving the loading motor, as shown in FIG. 1, not only peripheral components such as resistors R1, capacitors C1 and C2, zener diodes ZD, etc. are used. Since the integrated circuit IC1 is very expensive, there is a problem of increasing the cost of the video cassette recorder.

The present invention is to solve the problems as described above, the object of the present invention, instead of using an expensive dedicated IC, a simple configuration of the loading motor drive circuit that can easily control the loading motor to reduce the production cost of the product In providing the furnace.

The characteristic of the loading motor driving circuit according to the present invention for achieving the above object is to provide a control signal to the circuit unit and the deck unit for receiving a signal from a variety of input keys or various sensors to play a tape and the various key input unit or A loading motor driving circuit of a video cassette recorder having a microcomputer for generating signals (F, R) for forwarding, reversely rotating and stopping the loading motor in response to an input signal from a sensor, the loading motor driving circuit comprising: Two loading motor driving transistors which are turned on / off according to the state of the motor control signal to supply power to the loading motor, and are turned on / off according to the state of the loading motor control signal when power is applied to the transistors. Two current control transistors for controlling the current flowing through the motor to determine the rotation direction of the motor In the teoro points configured.

Hereinafter, a preferred embodiment of the loading motor driving circuit according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic block diagram of a general video cassette recorder having a loading motor driving circuit according to the present invention. Explain accordingly. Therefore, when the loading motor is rotated forward, the take-up reel is driven to perform fast forwarding of the tape (FF) or recording / reproducing operation. When the loading motor is reversed, the supply reel is driven to rewind the tape (REW). Assume that the operation is performed. In FIG. 2, when a user presses a predetermined key in the key matrix 1, the corresponding key input signal is applied to the micro computer 2, and the micro computer 2 is connected to the key matrix 1 or the sensor 3. The circuit section 4 and the deck section 5, which are capable of reproducing a tape by receiving an input signal from the system, are controlled. In addition, the microcomputer 2 provides control signals F and R to the loading motor driving circuit 6 according to the present invention so that the loading motor M can be forward, reverse or stopped. The loading motor driving circuit 6 is simply composed of the loading motor driving transistors Q1 and Q2 and the current control transistors Q3 and Q4 as shown in FIG.

3, when the control signals F and R generated by the microcomputer 2 are all at the low level L, that is, FR = LL, the transistors Q1 and Q2 are turned off so that the loading motor M The power supply (Vcc) is not applied at all, the loading motor (M) is not rotated. However, when the control signal is FR = HL, a high level is applied to the bases of the transistors Q1 and Q4, and a low level is applied to the bases of the transistors Q2 and Q4. At this time, since the transistor Q1 is turned on, the power supply Vcc is applied to one terminal A of the loading motor M through the collector-emitter of the transistor Q1, but the transistor Q2 is not turned on, so the loading motor The power supply Vcc is not applied to the other terminal B of (M). Since the transistor Q4 is turned on by the high level signal, the current flowing in the loading motor M becomes A → B, and the loading motor M is rotated forward to supply the reel to the take-up reel. Perform fast forward (FF) to rewind.

On the other hand, when the control signal is FR = LH, the transistors Q2 and Q3 are turned on. At this time, the other terminal B of the loading motor M supplies the power supply Vcc to the collector-emitter of the transistor Q2. Through the transistor Q3 is turned on, the current flowing in the loading motor M becomes B → A, and the loading motor M is reversely rotated. Thus, the rewind mode can be performed such that the tape is unwound from the take-up reel and wound onto the supply reel.

In addition, when the control signal is FR = HH, since all the transistors Q1 to Q4 are turned on, the potential difference between the terminals A and B of the loading motor M becomes the same so that the loading motor M does not rotate. . Therefore, it is preferable to program the control signal FR = HH in advance in the microcomputer 2 to perform the same function as FR = LL.

4 shows a control flowchart in which the microcomputer 2 drives the loading motor M and controls the deck unit 5. When the power is applied, the microcomputer 2 is driven from the key matrix 1. It continuously scans whether there is a key input (step S1). When the stop mode key is input from the key matrix 1 at the time of such key scan, the microcomputer 2 advances the program from step S2 to step S3 so that the control signal is FR = LL and the loading motor driving circuit is executed. As shown in (6), in this case, since the transistors Q1 and Q2 are both kept off as described above, the loading motor M does not rotate.

On the other hand, when it is determined in step S2 that the currently inputted key signal is not a stop key but fast-forward (FF), rewind (REW) or play / record key, the microcomputer 2 executes the program from step S2. The process proceeds to step S4. In this case, the microcomputer 2 first determines whether the input key is a rewind key. When the rewind key is input, the program proceeds from step S4 to step S5, where the microcomputer 2 provides the control signal to the loading motor drive circuit 6 with FR = LH. At this time, as can be seen in FIG. 3, the transistors Q2 and Q3 are turned on so that the loading motor M is reversely rotated as described above, so that the tape is rewound to an unillustrated supply reel. When the tape is wound around the supply reel, the start sensor of the various sensors 3 detects the start portion of the tape (which is a non-magnetic white portion) and provides a start detection signal to the microcomputer 2. Then, the microcomputer 2 recognizes that the tapes are all wound and advances the program from step S6 to step S7, and sets the control signal FR = LL to automatically load motor M as described above. Stop it.

On the other hand, if it is determined in step S4 that the currently input key is a fast forward (FF) key instead of a rewind key, the program proceeds from step S4 to step S8, but the microcomputer 2 The program is advanced from step S8 to step S9 to fast forward the tape. When the tape is all wound on the take-up reel during the fast forwarding, the end sensor of the various sensors 3 detects an end portion (white portion) of the tape and provides an end detection signal to the microcomputer 2. The microcomputer 2 then recognizes that the tape has been fast-forwarded and advances the program from step S10 to step S11 to perform the automatic rewind mode of the tape. In this case, the microcomputer 2 controls The program proceeds from step S11 to step S5 so that the signal is supplied to the loading motor drive circuit 6 with FR = LH to perform the above-described rewind mode.

However, if it is determined in step S8 that the currently pressed key is not a fast-forward key, the program proceeds from step S8 to step S12. When the playback and recording keys are pressed, the microcomputer 2 controls. The signal is applied to the loading motor driving circuit 6 with FR = HL to cause the loading motor M to rotate forward as described above (step S13). The deck unit 5 during the forward rotation of the loading motor M causes a loading system (not shown) to compress the tape to the rotating drum. When the loading of the tape is completed, the loading detection switch of the various sensors 3 is taped. A signal is provided to the microcomputer 2 indicating that the loading of is completed. At this time, when the microcomputer 2 senses a signal from the load detecting switch, the program advances from step S14 to step S15 to continuously operate the loading motor to play and record the tape.

As described above, according to the loading motor driving circuit according to the present invention, the loading motor can be easily driven with a simple circuit configuration instead of using an expensive dedicated integrated circuit.

Claims (1)

Signals for providing control signals to circuits and decks for receiving tapes from various input keys or sensors and reproducing tape, and for forwarding, reversing, and stopping the loading motor in response to input signals from the various input keys or sensors. A loading motor driving circuit of an audio cassette recorder having a microcomputer for generating (F, R); Power is supplied to the loading motor driving transistors Q1 and Q2 and the transistors Q1 and Q2 that are turned on / off according to the state of the control signals F and R generated from the microcomputer to apply the loading motor power. When applied, a loading motor driving circuit comprising current control transistors Q3 and Q4 for determining the rotational direction of the motor by controlling the current flowing in the motor by turning on / off according to the state of the control signals F and R. .