JPS5922298B2 - automatic stop device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an automatic stop device used in a magnetic recording/playback device, and aims to enable restart after automatic stop, and to reduce power consumption during automatic stop. It is something.

In general, automatic stop devices for detecting the end of a magnetic tape and automatically stopping the magnetic tape in a magnetic recording/playback device are known, but there are not many that are suitable for integrated circuit implementation.

The present inventor invented an automatic stop device as shown in FIG. 1 as an integrated circuit. In Figure 1,
1 is a fast-forward power switch that is turned on in conjunction with the fast-forward operation button; 2 is a recording power switch that is turned on in conjunction with the record button or playback button; 3 is a power source; 4 is a fast-forward constant current circuit; 5 is a constant current circuit for recording and reproducing 15, 6 is a latch circuit, 7 is
, 8 are transistors forming the latch circuit 6, 9, 10
is a constant current circuit, 11, 13, 15 are PNP transistors, 12, 14, 25 are NPN transistors, 16 is a motor governor, IT is a tape drive motor 20, 18, 1
9, 20, 21, 22 are resistors, 23 are capacitors, 26
is an output transistor, 2T is a frequency divider, 28 is a differential circuit,
29 is a rotation detection circuit, 30 is a reed switch, 31 is a magnet fixed to the reel stand, 32 is an oscillation circuit, 33
is frequency divider 252T) Differentiator circuit 28, output transistor 2
This is a constant current circuit that supplies current to 6. In FIG. 1, when the fast-forward power switch 1 or the recording/playback power switch 2 is turned on, a power supply voltage is applied to the constant current circuit 4 or 5.
A predetermined 30-degree voltage is applied to the latch circuit 6.

Therefore, in the latch circuit 6, one transistor T is turned on and the other transistor 8 is turned off by the action of the capacitor 23. As a result, transistors 11, 12, 1
3, 14, and 15 are turned on in sequence, and motor governors 16, 3
5. A predetermined voltage is applied to all of the constant current circuit 33, oscillation circuit 32, and rotation detection circuit 29. When the motor IT rotates, the magnet 31 rotates in conjunction with it.
Since the reed switch 31 repeats on and off, its output is sent to the frequency divider 2 via the rotation detection circuit 29 and the differentiation circuit 28.
The signal is now applied to the reset terminal 7 as a reset pulse. Therefore, even if a predetermined voltage is applied to the oscillation circuit 32 and the frequency divider 27 and they operate normally, the output of the oscillation circuit 32 will not be completely divided by the frequency divider 27 to the final stage and will always be The frequency divider 27 will be reset in the middle.
No output appears at the output terminal of . Therefore, in this state, the transistor 26 is turned off, and the transistors 7 and 8 forming the reset circuit 6 remain in the same state. Now, in FIG. 1, if the tape has run to the end and the reel has stopped rotating, the magnet 31 will also be in a stopped state, so there will be no set pulse to the frequency divider 27, and the frequency divider 27 will be able to control the oscillation circuit 32. The output is completely frequency-divided to the final stage, an output appears from the frequency divider 27, and the transistor 26 is turned on after a certain period of time. Therefore, the transistor 7 constituting the latch circuit 6
is turned off, and transistors 11, 12, 13, 14, 15
are sequentially turned off, and the rotation of the motor 17 is stopped. In this way, even with the automatic stop device shown in FIG.
2, power supply voltage is supplied to the motor 17, and when the tape reaches the end and the rotation of the reel stops, it is possible to automatically stop the power supply to the motor 17. However, with the automatic stop device shown in Figure 1,
When the transistors 11, 12, 13, 14, and 15 are turned off and the motor 17 stops rotating, the capacitors . Since a predetermined charge has been accumulated in the transistor 23, the transistor 8 is in an on state, so even if you immediately turn on the power switch 2 and try to enter the recording or playback state, there is a problem in that it is impossible. Ta. Furthermore, the automatic stop device shown in FIG. 1 has the problem that even when the motor 17 is automatically stopped, a dark current flows through the resistor 22 and the transistor 25, which is extremely inconvenient in terms of power consumption.

The present invention solves these problems. Embodiments of the present invention will be described below with reference to FIG. In FIG. 2, the same reference numerals as in FIG. 1 indicate the same components as in FIG. 34 to 40 are transistors, 41 and 42 are constant current sources, 43 is a capacitor, and 4
4 is a latch circuit for playback and recording, 45 and 46 are resistors, 47
is a latch circuit for fast forwarding.

In FIG. 2, when the power switch 1 for fast forwarding is turned on, the power supply voltage is applied to the latch circuit 47, the transistor 7 is turned on, and the transistors 11, 12, 34, 25, 14,
15 are turned on in sequence, the power supply voltage is applied to the constant current circuit 33, the oscillation circuit 32, and the rotation detection circuit 29, the motor 17 rotates, and the magnet 31 rotates to enter a normal fast-forwarding state.

When the tape is run to the end and the reel stops rotating, the magnet 31 also stops rotating, the output transistor 35 is turned on, and the operation of the latch circuit 47 is reversed, and the transistors 11, 12, 34, 25, 14, 15 are turned on. are all turned off, and the rotation of the motor 17 is stopped. By the way, in the embodiment shown in FIG. 2, the latch circuit 44 for recording and playback is separately provided, so when the power switch 1 for fast forwarding is turned on, the capacitor 43 that constitutes the latch circuit 4 for recording and playback is not charged. Therefore, when the recording/reproducing power switch 2 is turned on, the transistor 39 can be turned on immediately, and the transistors 38, 37, 36, 14, and 15 can be turned on in sequence, and the motor 17 can be driven. .

Further, in the embodiment shown in FIG. 2, the base of the transistor 25 connected to the motor governor 16 is connected to the collector of the transistor 34 driven by the output of the fast-forward latch circuit 47. When the transistor 34 is turned off, no current flows into the transistor 25, and power consumption during automatic shutdown can be significantly reduced. As is clear from the above embodiments, according to the automatic stop device of the present invention, after starting fast forwarding and automatically stopping at the end of the tape, it is possible to immediately enter the recording or playback state. There is little power consumption in the automatic stop state, which is extremely advantageous in practice.

Although the present invention requires a slightly larger number of components, all of these components can be integrated into an integrated circuit, and there is no problem in terms of manufacturing and cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electrical wiring diagram of an automatic stop device previously developed by the present inventor, and FIG. 2 is an electrical wiring diagram of an embodiment of the present invention. 1...Fast forward switch, 2...Recording/playback switch, 3...Power supply, 4, 5...
Constant current circuit, 7, 8, 11, 12, 14, 15, 25,
34-40...Transistor, 16...
・Motor governor, 17...Motor, 31...
...Magnet, 30...Reed switch,
32... Oscillation circuit, 29... Rotation detection circuit, 28... Differentiation circuit, 27... Frequency divider, 47, 44...・Latch circuit.

Claims (1)

[Claims] 1. The reel is rotated by applying the output of a rotation detection circuit that detects the rotation of the reel and generates a pulse signal according to the rotation of the reel as a reset signal of a frequency divider that sequentially divides the output of the oscillation circuit. In some cases, the output from the frequency divider does not appear, and the output from the frequency divider appears only when the reel is stopped rotating. The power switch, the fast-forward latch circuit connected to the recording/playback power switch, and the recording/playback latch circuit are connected in series to the motor by the respective outputs of the fast-forward latch circuit and the recording/playback latch circuit. When the reel stops rotating and a predetermined output appears from the frequency divider, the power supply to the motor is cut off and the motor is stopped. Each circuit is provided with a capacitor to operate the latch circuit in a predetermined direction when the power switch is turned on, and a motor governor is connected in series with the motor, and this motor governor is operated only by the output of the latch circuit for fast forwarding. An automatic stop device configured to be controlled by a controlled transistor.