JPH0648556B2 - Power supply circuit - Google Patents

Description

The present invention relates to an I ² L logic circuit and a power supply circuit of a memory circuit for switching the operating state of the I ² L logic circuit.

(B) Conventional Technology Some auto-reverse type tape recorders store the tape running direction when the operation is completed and make the tape run in the same direction as the above when the next operation is performed. As a method of storing the tape running direction, (1) mechanically holding the running direction switching mechanism that determines the tape running direction in the same operating condition, and (2) switching the tape running direction by rotating the motor rotation direction. In some cases, the rotation direction of the motor before the end of the operation is electrically stored, but recently, many tape recorders have started to change the operation, including the switching of the tape running direction, by a plunger. Therefore, a flip-flop is often used to electrically store the rotation direction of the motor. Storing the operating state by using a flip-flop is described in, for example, Syokai 59-14.
It is described in Japanese Patent No. 4935.

(C) Problems to be Solved by the Invention As described above, a flip-flop is used to store the tape running direction during operation even after operation, and the motor circuit such as a transistor is controlled by the output of the flip-flop. However, after the operation is restarted, the tape is made to run in the same direction as before.

By the way, in a portable tape recorder, since a battery is used as a power source, it is necessary that the current consumption is small and that the portable tape recorder be operated at a low voltage. Particularly in recent tape recorders, it is necessary to operate at a low voltage because it is operated by a single battery for downsizing. for that reason,
As the logic circuit controlled by the output of the flip-flop, the I ² L logic circuit that operates at the lowest voltage is used. The I ² L logic circuit can operate at a low voltage, but the current consumption per gate is 20 to 30 μA.
And there is a big drawback. Since the flip-flop stores the tape running direction during operation, it is necessary to constantly supply a holding current, but it is not necessary to supply a current to the I ² L logic circuit when not operating.

Therefore, the present invention provides a power supply circuit in which the operating current is supplied only to the memory circuit when it is not operating, and the operating current does not flow to the I ² L logic circuit, so that battery consumption is reduced.

The present invention further minimizes battery consumption during non-operation by supplying only the holding current required for memory retention of the memory circuit during non-operation, and at the same time supplies operating current to the I ² L logic circuit. The present invention provides a power supply circuit in which a large operating current is also supplied to a memory circuit to increase the operating speed of the memory circuit.

(D) Means for Solving the Problems The power supply circuit of the present invention is composed of a memory circuit to which an operating current is constantly supplied and an I ² L logic circuit to which an operating current is supplied only when the device is operating.

The power supply circuit of the present invention is a memory circuit to which a power supply current is supplied via the emitter / collector of the first transistor, a constant current circuit for flowing a constant current of the first transistor, and a starter circuit for starting the constant current circuit. And an I ² L logic circuit,
It is composed of an I ² L logic circuit which is turned on when the power switch is turned on and an operating current supply circuit which supplies an operating current to the starting circuit.

Further, in the power supply circuit of the present invention, the emitter / collector is connected in parallel to the emitter / collector of the first transistor,
It is composed of a second transistor operated by the operating current supply circuit.

(E) Operation The power supply circuit of the present invention has the above-described configuration, and when the device is not operating, the operating current flows only in the memory circuit, and the battery consumption is reduced.

If the power supply current to the memory circuit is supplied through the emitter / collector of the first transistor which is turned off when the device is not operating, the consumption of the battery during the non-operating is extremely reduced.

Further, since the second transistor is connected in parallel to the first transistor and the operating current is supplied to the memory circuit via the emitter / collector of the first transistor and the second transistor during operation, the operating speed of the memory circuit is increased.

(F) Embodiment FIG. 1 is a circuit diagram for explaining the operation principle of the power supply circuit of the present invention, FIG. 2 is an embodiment of the power supply circuit of the present invention, and FIG. ^{It is a 2} L logic circuit diagram.

In FIG. 1, (1) is a flip-flop, which is an input terminal
It has (2) and an output terminal (Q) (), and the operating current from the battery (3) is constantly supplied to the power supply terminals (4) and (5). (6) is an I ² L logic circuit, which is an output terminal (Q) of the flip-flop (1).
() Is connected to the input terminals (7) and (8), and an operating current from the battery (3) is applied to the power terminals (10) and (11) through the power switch (9).

The I ² L logic circuit (6) includes a PNP multi-collector transistor (12) for common bias, as shown in FIG.
Each base is the PNP multi-collector transistor (12)
Of the NPN multi-collector transistors (13) and (14) connected to the collectors of the NPN multi-collector transistors (13) and (14). The signal from terminal (Q) () is applied.

Since the I ² L logic circuit (6) is constructed as described above, the minimum operating voltage is NPN multi-collector transistor.
(13) Base emitter voltage of (14) 0.7V and PN
It can operate at about 0.8 volts, which is the sum of the collector-emitter saturation voltage of the P multi-collector transistor 12 of about 0.1 volts. On the other hand, however, the current consumption per gate is usually as large as 20 to 30 μA, which is a drawback.

When the power supply circuit shown in FIG. 1 is used for the reverse operation of the tape recorder, it is assumed that the tape is first run in the forward direction and is reproduced. This state is flip-flop (1)
If the output terminal (Q) is set to the high level and the output terminal () is set to the low level, the NPN multi-collector transistor (13) turns on and the NPN multi-collector transistor (14) turns off. The motor (not shown) is rotated in the forward direction, and the tape is run in the forward direction as described above. When the tape runs to the end, it detects that and generates a pulse, and the input terminal (2) of the flip-flop (1)
Apply a clock signal to. As a result, the flip-flop (1) is inverted, the output terminal (Q) is set to low level, and the output terminal
Since () is set to the high level, this time, the NPN multi-collector transistor (13) of the I ² L logic circuit (6) is turned off and the NPN multi-collector transistor (14) is turned on,
Until then, the tape is run in the reverse direction by rotating the motor in the reverse direction and playing in the reverse direction.

By the way, when the stop switch (not shown) is turned off in order to finish the reproduction of the tape, the power switch (9) is also turned off, so that the voltage from the battery (3) is supplied to the I ² L logic circuit (6). No, NPN multi-collector transistor (13)
All of (14) are turned off, and the reproduction is stopped by stopping the motor or the like. However, since the flip-flop (1) continues to be supplied with the current from the battery (3) to the power supply terminals (4) and (5), the flip-flop (1) maintains the operating state immediately before the stop. That is, if it is stopped in the reverse playback state described above, the flip-flop
The output terminal (Q) of (1) keeps the low level and the output terminal () keeps the high level. Therefore, the power switch (9) is turned on by the next reproduction operation, and the I ² L logic circuit is turned on.
When the voltage of the battery (3) is supplied to (6), the NPN multi-collector transistor (14) is turned on and the tape is reproduced in the reverse direction as before the stop.

Next, the embodiment of the present invention shown in FIG. 2 will be described.
(15) is a first transistor whose emitter / collector is connected between the power supply terminal (4) of the flip-flop (1) and the battery (3),
(16) is a constant current circuit for supplying a constant current to the first transistor (15), and is composed of transistors (17) to (20), and the transistors (19) and (20) and the first transistor (15) are current It is a mirror circuit. Reference numeral (21) is a starting circuit, which includes a transistor (22), a base (23) whose base is connected to the collector of the transistor (22) and a base which is connected to the collector of the transistor (23), and a collector (transistor (23)). 22) connected to the base of the transistor (2
4) and (25) is an operating current supply circuit consisting of transistors (26), (27) and (28), the collector of the transistor (28) is connected to the base of the transistor (22), and
The emitter / collector of (27) is connected to the power supply line and the I ² L logic circuit (6), and further the transistors (26) (27) (28)
Second transistor (29) that forms a current mirror circuit with
The emitter-collector of is connected in parallel with the emitter-collector of the first transistor (15).

The operation of FIG. 2 will be described next. The power switch (9) is turned on by operating the play button. As a result, the operating current supply circuit (25) is operated to supply an operating current of about 20 μA to the I ² L logic circuit (6) via the transistor (27). The operating current is supplied to the starting circuit (2
It is applied to the base of the transistor (22) of 1) to turn on the transistor (22) and turn on the transistors (17) to (23) that have been turned off until then. Therefore flip-flops
To (1), an operating current of about 20 μA is supplied via the first transistor (15) and an operating current of about 20 μA is supplied via the second transistor (29), and a large operating current of about 40 μA in total flows.

Since the flip-flop (1) stores the tape running direction as in FIG. 1, when the operating current is supplied to the I ² L logic circuit (6), for example, if the tape is running in the reverse direction. For example, the NPN multi-collector transistor shown in FIG.
When (14) is turned on, the motor is rotated in the reverse direction, and the reverse reproduction is performed.

A pulse is generated when the tape is run to the end. The flip-flop (1) inverts when it receives the pulse,
The output terminal (Q), which was low level until then, is set to high level and the NPN multi-collector transistor (13) is turned on.
Rotate the motor in the forward direction to run the tape in the forward direction.

In the above description, the flip-flop (1) is supplied with a large operating current through the first and second transistors (15) and (29) to increase the inversion speed, but the second transistor (29)
Is not necessary when it is not necessary to increase the reversal speed.

When the reproduction is finished, the power switch (9) is turned off.
As a result, the transistors (26) of the operating current supply circuit (25)
(28) is turned off and the supply of operating current to the I ² L logic circuit (6) is stopped. On the other hand, the transistor (22) of the starting circuit (21)
Is turned off when the transistor (24) is turned on, and the transistor (24) is turned off when the transistor (28) is turned off. Therefore, the transistors 17 to 20 and the first transistor 15 are turned off, and the holding current is supplied to the flip-flop 1 only through the emitter / collector of the turned off first transistor 15. This holding current is about 1 μA
However, it is sufficient because it only holds the holding state of the flip-flop (1).

(G) Effect of the Invention As described above, the power supply circuit of the present invention has both a storage circuit that stores an operating state such as a flip-flop when the device is operating and an I ² L logic circuit controlled by the storage circuit. A device that drives an I ² L logic circuit that operates at a low voltage but consumes a relatively large current by a battery because a holding current is supplied only to a memory circuit when the device does not operate Can be used efficiently.

If a large operating current is supplied to the memory circuit during operation and a small holding current required for holding is supplied during non-operation, battery consumption can be minimized while increasing the reversal speed.

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining the operating principle of the power supply circuit of the present invention, FIG. 2 is an embodiment of the power supply circuit of the present invention, and FIG. 3 is an I ² L logic circuit diagram used in the present invention. Is. Description of main figure numbers (1) …… Flip-flop, (6) …… I ² L logic circuit, (15) …… First transistor, (16) …… Constant current circuit,
(21) …… Starting circuit, (29) …… Second transistor.

Claims (2)

[Claims] 1. A storage circuit for supplying an operating current between an emitter and a collector of a transistor and storing and holding an operating state of a device, a constant current circuit for supplying a constant current to the transistor, and starting the constant current circuit. A starting circuit,
An I ² L logic circuit that is controlled according to the operating state of the memory circuit and switches the operating state of the device, and is turned on when the power switch is turned on and supplies an operating current to the I ² L logic circuit and the starting circuit. An operating current supply circuit for supplying the memory holding current to the memory circuit through the emitter-collector of the transistor in the off state when the power switch is in the off state,
When the power switch is in the ON state, the operating current supply circuit is turned on to supply the operating current to the I ² L logic circuit and the operating circuit to supply the operating current to start the constant current circuit. Let
A power supply circuit characterized in that an emitter-collector current of the transistor flowing in accordance with a current flowing through the constant current circuit is supplied as an operating current of the memory circuit. 2. A storage circuit for supplying an operating current between the emitter and collector of the first transistor and storing and holding the operating state of the device, a constant current circuit for supplying a constant current to the first transistor, and the constant current. A starter circuit for starting the circuit, an I ² L logic circuit which is controlled according to the operating state of the memory circuit and switches the operating state of the device, and an I ² L logic circuit which is turned on when a power switch is turned on and the I ²
An operating current supply circuit for supplying an operating current to the L logic circuit and the starting circuit, and an emitter-collector connected in parallel between the emitter-collector of the first transistor when the power switch is in an ON state, and the operating current. A second transistor whose base is supplied with the voltage from the supply circuit, and when the power switch is in the off state, the emitter of the first transistor in the off state
A memory holding current is supplied to the memory circuit through the collector, and when the power switch is in the ON state, the operating current supply circuit is turned on to supply the operating current to the I ² L logic circuit and the start circuit. The constant current circuit is started by supplying an operating current to the first constant current circuit, and the first current flowing in response to the current flowing in the constant current circuit.
A power supply circuit characterized in that an emitter-collector current of a transistor and an emitter-collector current of the second transistor flowing according to a current of the operating current supply circuit are supplied as an operating current of the memory circuit. .