JPH0454564Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention relates to an amplification integrated circuit for a tape recorder, and in particular, by changing the external circuit, it can be used for either a metal tape compatible function or a tape running direction display function. It also relates to something that can also be used.

[Technical background of the invention] As is well known, the integrated circuit (preamplifier IC) used for the main amplification of tape recorders is
For tape recorders with an auto-reverse function, it is equipped with an LED connection pin to connect a light emitting diode (hereinafter referred to as LED) to indicate the tape running direction.
It is equipped with an external circuit connection pin to connect an external circuit for metal tape, for a so-called auto-reverse compatible device that has the function of lighting up the LED, and for a tape recorder that has a metal tape recording and playback function. There are so-called metal tape compatible products that have the following characteristics.

[Problems in the Background Art] However, the conventional amplification integrated circuits as described above are manufactured as separate integrated circuits for auto-reverse and metal tape, and the user has to choose the one for the purpose of use. At present, they are selected and used as appropriate.

[Purpose of the invention] This invention was made based on the above circumstances, and by changing the external circuit with the same integrated circuit, it can be used for both metal tape compatible function and tape running direction display function. An object of the present invention is to provide an extremely good amplification integrated circuit for a tape recorder.

[Summary of the invention] That is, the amplification integrated circuit for a tape recorder according to the invention selectively changes to the first to third electrical states, which are different from each other, corresponding to the metal tape mode, normal tape mode, and tape running direction display mode. a first terminal that is set to a first electrical state and a second terminal that is selectively set to different first and second electrical states corresponding to forward running of the tape and reverse running of the tape; When the terminals of are set to the first electrical state, they are both in the first state, and when the first terminals are set to the second electrical state, they are both in the second state. 3
third and fourth terminals, one of which is in the first state and the other of which is in the second state, depending on the setting state of the second terminal when the electrical state is set to the electrical state of the third and fourth terminals; An external circuit compatible with a metal tape or a display unit for displaying the tape running direction, in which the fourth terminal is in a driving state in the first state and in a non-driving state in the second state, is selected as the third and fourth terminals. By connecting the same integrated circuit, the same integrated circuit can be used for both the metal tape compatible function and the tape running direction display function by simply changing the external circuit.

[Embodiment of the invention] Hereinafter, an embodiment of the invention will be described in detail with reference to the drawings. 1 and 2, 11 is the integrated circuit main body, output pins 11a and 11b for left and right channel signals, metal display pins 11c and 11d, mode switching pin 11e, tape running pin 11f, and tape forward playback. time left and right channel signal input pins 11g, 11h,
Input pins 11i and 11j are provided for left and right channel signals during tape reverse playback, respectively.

Among these, input pin 11 is supplied with the left channel playback signal when playing the tape in the forward and reverse directions.
g, 11i pass through the preamplifiers 12, 13, respectively, and then the forward/reverse switch 14 and the main amplifier 1.
5 to the output pin 11a. Also, an input pin 11 to which a right channel playback signal is supplied when playing the tape in the forward and reverse directions.
h, 11j pass through the preamplifiers 16, 17, respectively, and then the forward/reverse switch 18 and the main amplifier 1.
9 to the output pin 11b. The output pins 11a and 11b are connected to, for example, a speaker (not shown) via output terminals 20 and 21, respectively.

In addition, the above metal display pins 11c and 11d
are connected to common terminals 22a and 23a of changeover switches 22 and 23, respectively. Each of the first fixed terminals 22 of the changeover switches 22 and 23
b and 23b are connected in common through LEDs 24 and 25 for indicating the tape running direction and resistors Ra and Rb in series with the polarity shown, respectively, and the common connection point is connected to the power supply terminal 26 to which DC voltage +B is applied. has been done.

On the other hand, each of the second fixed terminals 22c and 23c of the changeover switches 22 and 23 is connected to a capacitor.
It is connected to the output terminals 20 and 21 via metal tape compatible external circuits 27 and 28 made up of Ca and Cb and resistors Rc and Rd. The changeover switches 22 and 23 are switched together in conjunction with each other.

Further, the mode switching pin 11e is connected to a common terminal 29a of the mode switching switch 29. This mode changeover switch 29 is used to switch between tape running direction display mode, normal tape mode, and metal tape mode, and its first fixed terminal 29b (corresponding to tape running direction display mode) is connected when DC voltage +Vcc is applied. The second fixed terminal 29c (corresponding to normal tape mode) is open, and the third fixed terminal 29d (corresponding to metal tape mode) is grounded.

Further, the tape running pin 11f is connected to a common terminal 31a of the tape running switch 31. Is this tape running switch 31 set so that the tape recorder mechanism (not shown) is running the tape in the forward direction? It is switched depending on whether the tape is running in the reverse direction, and the first fixed terminal 31b (corresponding to the tape forward running state) is opened, and the second fixed terminal 31c (corresponding to the tape running state in the reverse direction) is opened. ) is grounded.

Here, the mode switching pin 11e is connected to the collector of a pnp transistor Q1 via a constant current source 32 in the integrated circuit main body 11, and is also connected to a forward/reverse switching switch 34 via a constant current source 33. It is connected to the common terminal 34a of.

In addition, the above metal display pins 11c and 11d
are respectively inside the integrated circuit main body 11.
It is connected to the collectors of npn type transistors Q2 and Q3. The emitters of these transistors Q2 and Q3 are both grounded, and the bases are connected to the first and second fixed terminals 34b and 3 of the forward/reverse changeover switch 34.
4c, and to the collectors of pnp transistors Q4 and Q5. And these transistors Q1, Q4, Q
5 are connected in common, and their emitters are both connected to a power supply terminal 35 to which a DC voltage +Vc is applied.

Here, the forward/reverse switch 14, 18, 3
4, depending on whether the tape running pin 11f is in an open state or in a grounded state, that is, the tape running switch 3
1 is connected to the first fixed terminal 31b side or the second fixed terminal 31c side. That is, when the tape running switch 31 is in the open state as shown in FIG. 1, the forward/reverse changeover switches 14, 18, and 34 are in the state shown in FIG. 2. Therefore, the playback signals of the left and right channels during tape forward playback supplied to the input pins 11g and 11h are transmitted through the preamplifiers 12 and 16, the forward/reverse changeover switches 14 and 18, and the main amplifiers 15 and 19, respectively. and is guided to output pins 11a and 11b. Further, when the tape running switch 31 is in the grounded state opposite to that shown in FIG.
The situation is opposite to that shown in the figure. For this reason,
The playback signals of the left and right channels during tape reverse playback supplied to the input pins 11i and 11j are sent to the preamplifiers 13 and 17 and the forward/reverse changeover switches 14 and 1.
8 and main amplifiers 15 and 19, respectively, to output pins 11a and 11b.

Further, the constant current sources 32 and 33 are connected depending on whether the mode switching pin 11e is applied with DC voltage +Vcc, open, or grounded, that is, the mode switching switch 29 is connected to the first fixed terminal 29b. The drive is controlled depending on whether the terminal is connected to the second fixed terminal 29c or the third fixed terminal 29d. That is, when the mode changeover switch 29 is connected to the first fixed terminal 29b side, the constant current source 33
is in a driven state, and the constant current source 32 is in a non-driven state. Further, when the mode changeover switch 29 is connected to the third fixed terminal 29d side, the constant current source 32 is in a driven state and the constant current source 33 is in a non-driven state.
Further, when the mode changeover switch 29 is connected to the second fixed terminal 29c side, the constant current sources 32, 33
Both are in a non-driving state.

Further, when the mode changeover switch 29 is connected to the first fixed terminal 29b side, the changeover switches 22 and 23 are connected to the first fixed terminals 22b and 29b.
3b side, and the mode changeover switch 2 is switched to the 3b side.
9 is connected to the second and third fixed terminals 29c and 29d, both the second fixed terminals 22c and 23
It can be switched to the c side.

First, when playing back a normal tape, the mode changeover switch 29 is connected to the second fixed terminal 29c. Then, the constant current sources 32 and 33 are both in the non-driven state, and the transistors Q2 and Q3 are both in the off state (that is, the metal display pins 11c and 11d are both in the high impedance state) regardless of the switching state of the tape running switch 31. It will be done. Therefore, the reproduction signals of the left and right channels output from the output pins 11a and 11b of the integrated circuit main body 11 have no influence on the external circuits 27 and 28 connected to the metal display pins 11c and 11d. The normal tape playback signal is guided to the output terminals 20 and 21, where the normal tape playback signal is amplified.

Next, when playing metal tapes,
The mode selector switch 29 is connected to the third fixed terminal 2.
Connect to 9d side. Then, only the constant current source 32 is driven, and the transistors Q2 and Q3 are both turned on regardless of the switching state of the tape running switch 31 (that is, the metal display pin 11c,
11d are both in a low impedance state). Therefore, the output pin 11 of the integrated circuit body 11
The playback signals of the left and right channels output from a and 11b are output from metal display pins 11c and 11d.
Under the influence of the external circuits 27 and 28 connected to the metal-compatible state, the output terminals 20 and
21, where the metal tape reproduction signal is amplified.

Further, when displaying the tape running direction, the mode changeover switch 29 is connected to the first fixed terminal 29b side. Then, the constant current source 3
Only transistor Q3 is in the driving state, and transistors Q2 and Q
3 is selectively turned on in accordance with the switching state of the tape running switch 31. Therefore, the LED 24 or 25 connected to the metal display pins 11c and 11d corresponding to the turned-on transistor Q2 or Q3 turns on, and the tape running direction is displayed here. . Also. Integrated circuit main body 11 is output pin 1
The reproduction signals of the left and right channels outputted from 1a and 11b are directly led to output terminals 20 and 21, where the normal tape reproduction signal is amplified and the tape running direction is displayed.

Therefore, according to the configuration of the above embodiment, the user can freely select and use one integrated circuit main body 11 for the tape running direction display function (that is, for auto-reverse compatibility) and for the metal tape compatibility. It is something that you will be able to do. Further, the number of pins of the integrated circuit main body 11 does not increase, making it extremely suitable for practical use.

Note that this invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the invention] Therefore, as detailed above, according to this invention, the same integrated circuit can be used for both the metal tape compatible function and the tape running direction display function by changing the external circuit. Thus, it is possible to provide an extremely good amplification integrated circuit for a tape recorder.

[Brief explanation of the drawing]

FIGS. 1 and 2 are block circuit configuration diagrams showing one embodiment of an amplifying integrated circuit for a tape recorder according to the present invention, respectively. 11... integrated circuit body, 12, 13... preamplifier, 14... forward/reverse changeover switch, 15... main amplifier, 16, 17... preamplifier, 18... forward/reverse changeover switch, 19... Main amplifier, 20, 21...
...Output terminal, 22, 23...Selector switch, 2
4, 25...LED, 26...power terminal, 27,
28... External circuit, 29... Mode selection switch, 30... Power terminal, 31... Tape running switch, 32, 33... Constant current source, 34... Forward/reverse switching switch, 35... Power terminal.

Claims (1)

[Scope of utility model registration request] a first terminal that is selectively set to different first to third electrical states corresponding to metal tape mode, normal tape mode, and tape running direction display mode; a second terminal that is selectively set to correspondingly different first and second electrical states, and when the first terminal is set to the first electrical state, both are in the first state; When the first terminal is set to a second electrical state, both are in the second state, and when the first terminal is set to a third electrical state, according to the setting state of the second terminal. third and fourth terminals, one of which is in the first state and the other in the second state;
An external circuit compatible with metal tape or a display unit for displaying the tape running direction is selectively connected to the third and fourth terminals, the terminals being in a driving state in the first state and in a non-driving state in the second state. An integrated circuit for amplification of a tape recorder, characterized in that it is connected to each other.