JPS5939819B2 - Drive circuit for magnetic recording and playback equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when the tape being recorded or played reaches the end, the tape running motor automatically stops, and if the rewind operation is performed in that state, the review state is entered and the rewind operation is then performed. When you release the button, it automatically returns to the recording or playback state, and when the tape being rewound reaches the end, the motor for running the tape automatically stops, and if you perform a recording or playback operation in that state, it will enter the queue state. The purpose of the present invention is to provide a drive circuit for a recording/playback device which is capable of automatically returning to the rewinding state when the recording or playback operation is subsequently canceled, has excellent operability, and is suitable for integration into an integrated circuit. It is something.

Although drive circuits for magnetic recording and reproducing devices of this type are generally known, there are not many that are suitable for integration into integrated circuits.

The present inventor previously developed a drive circuit for a magnetic recording/reproducing device as shown in FIG. 1, which is suitable for integrated circuit implementation.
In FIG. 1, 1 is a recording/playback power switch that is turned on in conjunction with recording and playback operations; 2 is a fast-winding power switch that is turned on in conjunction with fast-forwarding and rewinding operations;
3 is a latch circuit for recording and playback, 4 is a latch circuit for fast winding,
5 to 8 are transistors forming latch circuits 3 and 4, respectively; 9, 11, 13, and 15 | 16 are PNP transistors; 10, 12, and 14 are NPN transistors; IT is a frequency divider; and 18 and 19 are latch circuits, respectively. 3 and 4 are constant current circuits that supply current, 20 is an oscillation circuit, 21 is a motor,
22 is a power supply, 23 and 24 are power switches 1 and 2, respectively.
25 is a reset circuit, 26 is a rotation detection circuit, 2T is a reed switch, and 28 is a magnet connected to the reel. In FIG. 1, when a recording or playback operation is performed, the power switch 1 for recording and playback is turned on, so that a predetermined current flows into the latch circuit 3 for recording and playback through the constant current circuit 18.

Then, when the power switch 1 is turned on, the trigger is simultaneously activated.
Since the circuit 23 operates, a negative trigger pulse is output from the trigger circuit 23 and is applied to the base of the transistor 5. Therefore, the latch circuit 3 is the transistor 5
is off, and transistor 6 is turned on, which subsequently turns on transistors 9, 10, 11, 12, and 13 in sequence. Therefore, a power supply voltage is applied to each of the motor 21, the oscillation circuit 20, and the rotation detection circuit 26 via the transistor 13, and the magnetic recording/reproducing device enters a recording or reproducing state. In this state, since the magnetic tape is being run by the rotation of the motor 21, the reel stand is also rotating, and the magnet 28 attached to the reel stand is also rotating. Therefore, the reed switch 27 is repeatedly turned on and off, and a predetermined output pulse appears from the rotation detection circuit 26. Since the output pulse is applied to the reset terminal of the frequency divider 17 via the reset circuit 25, a predetermined voltage is applied to the oscillation circuit 20 and the frequency divider 17, even if these are operating normally. The output of the oscillation circuit 20 is not completely divided by the frequency divider 17 until the final stage, but is always reset midway through. Therefore, in this state, no output appears from the frequency divider 17. If the magnetic tape currently being recorded or played reaches its end, the rotation of the reel will stop, and so the rotation of the magnet 28 will also stop.

Therefore, at this time, the reed switch 27 is stopped in either the on or off state, and the frequency divider 1
No more set pulse to 7. Therefore, frequency divider 17
The output of the oscillation circuit 20 is completely frequency-divided up to the final stage, and a predetermined output appears from the frequency divider 17 after a certain period of time. The output of the frequency divider 17 is applied via the output transistor to the base of the transistor 6 constituting the latch circuit 3, so that the latch circuit 3 has the transistor 6 turned off and the transistor 5 turned on. As a result, the transistors 9, 10, 11, 12, and 13 are turned off in sequence, the rotation of the motor 21 is stopped, and the oscillation circuit 20, the frequency divider 17, and the rotation detection circuit 26 are all rendered inactive. In this state,
If the rewinding operation is continued, the power switch 2 for fast winding is turned on, so current is supplied to the latch circuit 4 for fast winding, forming the latch circuit 7 for fast winding, and the base of the transistor 7. A negative trigger pulse obtained by the trigger circuit 24 is applied to the trigger circuit 24.

Therefore, in latch 4, transistor 8 is turned on and transistor 7 is turned off, which subsequently turns on transistors 15, 14, 16, 12, and 13 in sequence. As a result, voltages are applied to each of the motor 21, the oscillation circuit 20, and the rotation detection circuit 26 in the same way as when the recording/reproducing power switch 1 is turned on, and the magnetic recording/reproducing apparatus enters the review state. In this way, the drive circuit shown in Fig. 1 can also automatically stop the rotation of the motor 21 when the magnetic tape being recorded or played reaches its end, and if the rewinding operation is subsequently performed in this state. It can be automatically set to the first review status.

However, in the drive circuit shown in FIG. 1, even if an attempt is made to cancel the rewind operation from the review state and immediately switch to the recording or playback state, the transistor 6 constituting the latch circuit 3 for recording and playback will not divide the frequency at the time of automatic stop. The transistor 13 is turned off by the output of the device 17 and remains in that state, so if the rewinding operation is simply canceled, the transistor 13 will be turned off, and the motor 21 will not rotate and the state will be switched to recording or playback. I can't. Therefore, when switching to the recording or playback state, it was necessary not only to cancel the rewind operation, but also to cancel the recording or playback operation each time and then restart the recording or playback operation. In addition, this means that after performing a rewind operation and turning on the power switch 2, the rotation of the motor 21 is automatically stopped at the end of the tape, and then the recording or playback operation is performed to bring the recording state into a single state. The same applies when the recording or playback operation is subsequently canceled and the original rewinding state is returned again.

The present invention solves these problems, and when returning from the review state to the recording or playback state, it is only necessary to cancel the rewind operation, and when returning from the record state to the rewind state, The configuration is such that simply canceling the recording or playback operation is sufficient.

FIG. 2 is a specific electrical wiring diagram of an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same components as in FIG. 1.

The difference between FIG. 2 and FIG. 1 is that the recording/playback latch circuit 3
The collector of one transistor 6 constituting the fast winding latch circuit 4 is connected to the base of the other transistor 7 constituting the fast winding latch circuit 4, and the collector of one transistor 8 constituting the fast winding latch circuit 4 is connected to the recording/reproducing latch circuit. 3 is connected to the base of the other transistor 5 constituting the transistor 3. With this configuration, in the embodiment shown in FIG. 2, when a recording or playback operation is performed, the power switch 1 is turned on, the motor 21 is rotated, and the magnetic recording/playback device enters the recording or playback state. In this state, after the tape has run to the end and the rotation of the motor 21 has automatically stopped, if you want to start the rewinding operation and turn on the power switch 2 to set the review state and return to the recording or playback state, simply It is sufficient to return to the recording or playback state simply by canceling the previous fast-forward operation. That is, even in the embodiment shown in FIG. 2, when the tape runs to the end and automatically stops, the latch circuit 3 for recording and playback has the transistor 6 off and the transistor 5 on, but the review When the rewind operation is started and the power switch 2 is turned on, at the same time one of the transistors 8 forming the latch circuit 4 for fast winding is turned on. Since the other transistor 5 constituting the latch circuit 3 is turned off and the one transistor 6 constituting the latch circuit 3 is turned on, the transistor 13 will not operate the latch circuit 3 even if the rewinding operation is canceled thereafter. The on state is maintained by the output of the constituent transistor 6, so there is no need to cancel the recording or playback operation each time and start the recording or playback operation again as shown in FIG. Simply canceling the rewinding operation is enough to switch to recording or playback mode. Note that the speed switching of the motor 21 between playback (recording) and fast winding is not shown, but in reality, the transistor 16 is configured as a multi-collector and the collector controls the drive circuit of the motor 21. When power switches 1 and 2 are both on, transistors 11 and 16 are both on,
In addition, it is configured to perform one review and one read operation.

Further, the motor 21 rotates in only one direction, and the tape rewinding and fast forwarding directions are mechanically switched using gears, pulleys, etc. This means that after rewinding, turn on the power switch 2, then automatically stop the rotation of the motor 21 at the end of the tape, perform the recording or playback operation, set the recording state, and then continue recording or playing. The same applies when canceling the playback operation and returning to the original rewinding state.

That is, in this case, when the recording or playback operation is started and the power switch 1 is turned on in order to set the recording/playback latch circuit 3, the fast winding latch circuit is activated by the output of the transistor 6 that constitutes the recording/playback latch circuit 3. Since the other transistor 7 constituting the fast winding latch circuit 4 is turned off and one transistor 8 constituting the fast winding latch circuit 4 is turned on, the transistor 13 remains in the on state even if the recording or playback operation is canceled. Therefore, without having to cancel the rewinding operation each time and then starting the rewinding operation again, it is possible to immediately enter the rewinding state simply by canceling the recording or playback operation. As is clear from the above embodiments, according to the first drive circuit of the present invention, after automatically stopping the running of the tape, it starts running the tape in a different mode, and then runs the tape in the original mode midway through. Even if you want to do so, the operation is extremely simple.

In the embodiment, only the case where the recording or playback state is switched to the review state and then switched back to the recording or playback state, and the case where the rewind state is switched to the playback state and then switched back to the rewind state are explained. , 2 are turned on in connection with a recording or playback operation, a fast forwarding operation, or a rewinding operation, respectively. Therefore, it is also possible to sequentially switch the mode in each order other than the above by combining each operation.

[Brief explanation of the drawing]

Figure 1 shows one of the magnetic recording and reproducing devices that the inventor developed earlier.
A specific electrical wiring diagram in the drive circuit. FIG. 2 is a specific electrical wiring diagram of an embodiment of the present invention. 1... Power switch for recording/playback, 2... Power switch for fast winding, 3... Latch circuit for recording/playback, 4... Latch for fast winding. Circuit, 17...
・Frequency divider, 18, 19... Constant current circuit, 20.
...Oscillation circuit, 21...Motor, 22.
...Power supply, 23, 24 ... Triker circuit, 25 ... Reset circuit, 26 ... Rotation detection circuit, 27 ... Reed switch , 28・
...Magnet.

Claims (1)

[Claims] 1 When the power is turned on and the first
A latch circuit for recording and playback is switched to a stable state, and then switched to a second stable state when the tape has run to the end, and a latch circuit for recording and playback is switched to the first stable state when the power is turned on when fast forwarding or rewinding is performed. and a tape running motor that operates when these latch circuits are in the first stable state. , and the one latch circuit and the other latch circuit are such that when one latch circuit is in the second stable state and the other latch circuit is switched to the first stable state, the one latch circuit is switched to the first stable state. A drive circuit for a magnetic recording and reproducing device, characterized in that the drive circuits are interconnected so as to be forcibly brought into a first stable state by the output of the other latch circuit.