JPH075597Y2 - Power supply circuit for tape recorder with radio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a power supply circuit of a tape recorder with a radio having a timer circuit.

(B) Conventional technology Incorporating a radio receiver into the tape recorder and using the tape recorder or radio receiver alone, the radio receiver and the tape recorder are operated simultaneously, and the broadcast signal received by the radio receiver is received. There is a tape recorder with a radio that allows recording with a tape recorder. When a timer circuit is used in such a tape recorder with radio, the radio receiver is automatically operated when the time set by the timer is reached even when not in use, and the radio broadcast signal received by operating the tape recorder is recorded. There is something like this.

As shown in FIG. 2, such a tape recorder with a radio conventionally controls a control transistor (2) by a timer output signal from a timer circuit (1), and a switching transistor which is turned on and off by the control transistor (2). Timer switch (4) on the emitter and collector of (3)
Are connected. When the timer circuit (1) is not used, the timer switch (4) is turned on, and the changeover switch (5) is switched to the state shown in the figure, the power supply voltage is applied to the radio / amplification circuit (6), and the radio broadcast signal is transmitted. When the recording button is turned on in such a state, the tape switch (7) is turned on, the power supply voltage is supplied to the motor circuit (8), the motor is rotated to put the tape recorder into the recording state, and the received radio broadcast signal is transmitted. Record. On the other hand, when the selector switch (5) is switched to the side opposite to that shown in the figure and the reproduction button is pressed, the tape switch (7) is turned on, voltage is supplied to the motor circuit (8), and the radio / amplification circuit (via the selector switch (5) is supplied. A power supply voltage is supplied to 6) to bring the device into a reproducing state. On the other hand, when the timer switch (4) is turned off when timer recording is performed using the timer circuit (1), the control transistor (2) is turned off without generating a timer output signal from the timer circuit (1) until the set time comes. Since the switching transistor (3) is not turned on, the power supply voltage is not supplied to the radio / amplification circuit (6) and the motor circuit (8). However, when the set time comes, a timer output signal is generated from the timer circuit (1) to turn on the control transistor (2), and the switching transistor (3) is also turned on, so that the changeover switch (5) is switched to the state shown in the figure. If the tape switch (7) is turned on, the radio / amplifying circuit (6) is operated and the motor circuit (8) is also operated to record the received broadcast signal.

(C) Problems to be solved by the invention As described above, the conventional power supply circuit has the timer switch (4) in parallel with the switching transistor (3) which is turned on / off by the timer output from the timer circuit (1). When the timer circuit (1) is connected, current flows to the radio / amplification circuit (6) and the motor circuit (8) through the timer switch (4), so the timer switch (4) is connected.
Since it is necessary to increase the current capacity of the switch, the switch cannot be increased in size.

The present invention provides a power supply circuit for a tape recorder with a radio that eliminates the above drawbacks.

(D) Means for solving the problem The power supply circuit of the tape recorder with a radio of the present invention generates a timer output signal at a set time and a timer circuit that generates a different operation signal when the time is set and when it is not set. Between the power supply and the radio / amplification circuit, a switching transistor that is turned on / off by an operation signal from the timer circuit, a timer output signal generated by the timer circuit at a set time or a control transistor controlled by the switching transistor, A power supply transistor connected between the power supply and the motor circuit, a second power supply transistor connected between the power supply and the motor circuit and turned on by the control transistor, and a power supply voltage from the power supply First only via a tape switch or
It is composed of a power supply transistor and a changeover switch which supplies the second power supply transistor.

(E) Action Since the power supply circuit of the tape recorder with radio of the present invention has the above-mentioned configuration, the opening / closing transistor is turned off by the operation signal from the timer circuit when the time is set, the control transistor is turned off, and the first power supply is turned on. Transistor and second
Bias current to the power transistor is cut off. Therefore, the power supply voltage is not supplied to the radio / amplification circuit and the motor circuit, and when the set time comes, the control transistor is turned on by the timer output signal from the timer circuit.
The power supply voltage is supplied to the amplifier circuit to receive the broadcast signal. On the other hand, the power supply voltage is supplied to the motor circuit through the tape switch which is turned on in advance, and the tape recorder is set in the recording state to record the broadcast signal. When the time is not set, the open / close transistor is turned off by the operation signal from the timer circuit and the bias current is supplied to the control transistor. Therefore, the radio receiver, the tape recorder, or both are operated according to the closing of the changeover switch or the tape switch. be able to.

(F) Embodiment An embodiment of the power supply circuit of the tape recorder with radio of the present invention will be described with reference to FIG.

(10) is a timer circuit, which outputs a timer output signal at the time setting time (11), V _SS terminal (12) and V _DD
It has a terminal (13). (14) is a time switch for switching the timer circuit (10) to a time setting state or a time non-setting state, and (15) is the time switching switch (1
The open / close transistor is turned on / off at 4), and the base of the (16) is the battery (17) and the output terminal (11) of the timer circuit (10) is a high resistance bias resistor (18) (19), respectively.
A first control transistor connected via (20), a collector of a switching transistor (15) between the connection point of the bias resistors (18) and (19) and the V _DD terminal (13) of the timer circuit (10). The emitter is connected. (21) is a second control transistor controlled by the first control transistor (16), (22) is a changeover switch for switching between radio and tape, and (23) is a play button or operation button of a tape recorder. A tape switch that is turned on by
(24) is a first power transistor connected together with the changeover switch (22) between the battery (17) and the radio / amplification circuit (25), and (27) is a tape between the battery (17) and the motor circuit (26). A second power transistor connected via a switch (23).

Next, the operation of the power supply circuit of the tape recorder with a radio of the present invention will be described.

In the unused state, the changeover switch (22) is changed over to the tape side different from the one shown and the tape switch (23) is turned off. Therefore, the radio / amplification circuit (25) and the motor circuit (26) are connected to the battery (17). The voltage is not supplied and the unit is in a non-operation state. Further, when the time switch (14) is switched to a time non-setting state different from that shown in the figure, since the open / close transistor (15) is turned off, the first control transistor (16) is provided with the bias resistors (18) and (19). Although a bias voltage is applied through the bias resistor (18) (19), the bias current is about 3 because the resistance value of the bias resistors (18) and (19) is as high as 1 MΩ.
It becomes less than μA and has almost no effect on the consumption of the battery (17).

When the playback button (not shown) is pressed in this state to put the tape recorder in the playback state, the tape switch (23) is turned on, and the second power transistor (27) is supplied with the battery ( The voltage from the battery (17) is also supplied to the first power supply transistor (24) through the tape switch (23) and the changeover switch (22). On the other hand, since the bias current is supplied to the first control transistor (16), the first control transistor (1)
6) is turned on, and the bias current is amplified by the second control transistor (21).
4) and the second power transistor (27) to the bias resistor (2
8) A bias current is supplied via (29) to the first power transistor (24) and the second power transistor (27).
Turn on the radio / amplifier circuit (25) and motor circuit (26)
Is supplied with a current from the battery (17). In this case, the operating current of the radio / amplifier circuit (25) may be small, so the bias resistance (28) of the first power transistor (24) is 2.2K.
The bias resistance (29) is set to 680 Ω because the motor circuit (26) requires a large operating current, while making the first power supply transistor (24) an unnecessarily large bias current from flowing. It is made small so that a large bias current is supplied to the second power supply transistor (27). As described above, the motor is rotated by the electric current flowing through the motor circuit (26), the tape recorder is put into a reproducing state, the information signal recorded on the tape is reproduced, and the information signal is amplified by the amplifying circuit so that the speaker or the like is reproduced. To drive. At this time, the radio circuit is not operated.

Next, when it is desired to receive a radio broadcast, the selector switch (22) is switched to the radio side shown. Then, the voltage from the battery (17) is applied to the first power transistor (24) through the changeover switch (22), and the first power transistor (2)
4) is turned on and the above voltage is supplied to the radio / amplification circuit (25) to bring it into an operating state. Therefore, when one channel is selected, one broadcast signal is received, and the speaker is sounded after being amplified by the amplifier circuit (25). Since the operating current of the radio / amplifying circuit (25) is small, the bias current supplied to the first power supply transistor (24) is small and the consumption of the battery (17) is reduced. When you want to record the received broadcast signal, press the record button to turn on the tape switch (23) and supply the voltage from the battery (17) to the motor circuit (26) to rotate the motor and put it in the recording state. Therefore, the received broadcast signal is recorded.

By the way, when it is desired to record a broadcast signal during absence, the time selector switch (14) is switched to the illustrated time setting state. Then, a voltage of 1.5 V is applied from the V _SS terminal (12) of the timer circuit (10) to the base of the switching transistor (15) to arm the emitter, so that the switching transistor (15) is turned on and the first control transistor (15) is turned on. Bias current to 16) is cut off. Therefore, even if the selector switch (22) is switched to the radio side as shown in the figure and the tape switch (23) is turned on as described above, the radio / amplification circuit (2
5) and the motor circuit (26) are not supplied with voltage and are in a standby state.

Therefore, if the timer circuit (10) is set at the start time of the broadcast signal desired to be recorded, a timer output signal is generated from the timer output terminal (11) at the start time, and the timer output signal is the bias resistor (20). Is applied to the base of the first control transistor (16) via to turn on the first control transistor (16). As a result, the second control transistor (21) is also turned on, the first power transistor (24) and the second power transistor (27) are turned on, and the radio
A voltage is supplied to the amplifier circuit (25) to receive a broadcast signal selected in advance, and at this time, the tape signal is recorded in a tape recorder.

(G) Effect of the invention As described above, the power supply circuit of the tape recorder with a radio of the present invention separates the power supply path between the radio / amplification circuit and the motor circuit, and connects the power supply transistors to each of them, and these power supply transistors are connected to the radio The bias current is set so that the minimum operating current required for the amplifier circuit and the motor circuit flows. Therefore, particularly when receiving a radio broadcast, the bias current flowing through the power supply transistor or the like is reduced, and battery consumption can be reduced. Further, since the operation signal generated by the timer circuit is different between when the time is set and when the time is not set, the opening / closing transistor is turned on / off, and the bias current of the control transistor for controlling the power supply transistor is cut off. It is possible to eliminate the need for a changeover switch for switching the power supply circuit between time setting and non-time setting as in the conventional case.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a power supply circuit of a tape recorder with a radio of the present invention, and FIG. 2 is a circuit diagram of a power supply circuit of a conventional tape recorder with a radio. Explanation of main drawing numbers (10) …… Timer circuit, (11) …… Timer output terminal, (15) …… Opening and closing transistor, (16) (21) …… First and second control transistors, (22) ...... Changeover switch, (23) …… Tape switch, (24) …… First power transistor, (25) …… Radio / amplifier circuit, (26) ……
Motor circuit, (27) …… Second power transistor.

Claims (1)

[Scope of utility model registration request] 1. A timer circuit that generates a timer output signal at a set time and a different operation signal when the time is set and when the time is not set, and on / off by an operation signal output from the timer circuit. An emitter / collector path is connected between the power supply and the radio / amplifier circuit, and an open / close transistor, a timer output signal output from the timer circuit at a set time or a control transistor whose operation is controlled by the open / close transistor. A first power supply transistor whose operation is controlled by the control transistor, and a second power supply transistor which is connected between the power supply and the motor circuit and whose operation is controlled by the control transistor Power transistor and tape switch closed when the tape recorder is in operation The power supply first when in the radio-use position switches the radio using the tape used
A switching switch for supplying power to the transistor and supplying power to the first transistor and the second transistor via the tape switch when in the tape use position, and when the time is not set, the opening / closing transistor is turned off. A bias current is constantly supplied to the control transistor by the power switch, and when the changeover switch is switched to the radio use position, the first power transistor is turned on to supply power to the radio / amplification circuit.
Further, when the tape switch is closed, power is supplied to the radio / amplification circuit and the motor circuit by turning on the first power transistor and the second power transistor, and the timer circuit sets when the time is set. A bias current is supplied to the control transistor by a timer output signal output at time, so that when the changeover switch is switched to the radio use position, the first power supply transistor is turned on to turn on the radio / amplification circuit. Power is supplied, and power is supplied to the radio / amplification circuit and the motor circuit by turning on the first power transistor and the second power transistor when the tape switch is closed. Power circuit for tape recorder with radio.