JPS6322510B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a light source control device in which a predetermined light source among a plurality of light sources is turned on when the power is turned on, and unnecessary light sources are turned off without turning on for a moment when the power is turned off. purpose.

Recent television receivers are capable of monaural broadcasting,
Can receive double broadcast and stereo broadcast,
Four switches A, B, C, D and corresponding four light sources are provided so that the two speakers can be set in four states. In the case of monaural broadcasting, monaural broadcasting is emitted from the two speakers no matter which switch is pressed. In the case of dual broadcasting, pressing switch A will emit Japanese broadcasts from both speakers, pressing switch B will emit English broadcasts from both speakers, and pressing switch C will emit Japanese broadcasts from the left speaker. , the English broadcast will be emitted from the right speaker, and when switch D is pressed, the Japanese broadcast will be emitted from both speakers. Next, in the case of stereo broadcasting, pressing any of switches A, B, or C will cause stereo broadcasting to be emitted from both speakers, and pressing switch D will cause monaural sound to be emitted.

These switches A, B, C, and D are touch switches, for example, and send pulse-like signals. Therefore, since the A switch is generally pressed when the power is turned on, the light source corresponding to each switch must also ensure that the lamp corresponding to the A switch is lit.

Therefore, the present invention aims to provide a light source control device in which a predetermined light source is always turned on when the power is turned on when a plurality of light sources are present.Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, light emitting diodes 2b and 2a, which are light sources, are connected between the DC power supply terminal 1 and the reference potential point.
Connect the series circuit with 2b and 2c. Furthermore, a series circuit of transistor 3, resistors 4, 5, and transistor 6, a series circuit of resistors 7, 8, and transistor 9, a series circuit of transistor 10, resistors 11, 12, and transistor 13 are connected between the DC power supply terminal 1 and the reference potential point. A series circuit of resistors 14 and 15 and a transistor 16 are connected. The connection point between resistors 4 and 5 is the light emitting diode 2a.
and 2b, and the connection point between resistors 11 and 12 is connected to the connection point between light emitting diodes 2c and 2b. Emitter of transistor 3
A resistor 17 is connected between the bases, and a transistor 18 is connected between the base of the transistor 3 and the DC power supply terminal 1. This transistor 18
The base of is connected to the connection point between resistors 7 and 8. Further, a resistor 19 is connected between the emitter and the base of the transistor 10, and a transistor 2 is connected between the base of the transistor 10 and the DC power supply terminal 1.
0 is connected. The base of transistor 20 is connected to the connection point between resistors 14 and 15.
The bases of the transistors 9, 6, 16, and 13 are connected to four output terminals of the lamp switching circuit 21a of the mode switching circuit 21. Furthermore, transistors 22, 23, 24, and 25 are connected to the bases of the transistors 6, 9, 13, and 16 and the reference potential point. A voltage dividing circuit consisting of a series circuit of resistors 26a and 26b is provided between the terminal 1 and the reference potential point, and the bases of transistors 27 and 28 are connected to the voltage dividing point. The emitters of these transistors 27 and 28 are connected to the emitters of transistors 29 and 30 whose collectors are connected to a reference potential. Emitters of transistors 27 and 29,
Emitters 28 and 30 are transistors 31 and 32
It is connected to terminal 1 through a series circuit of resistors 33 and 34. A series circuit of a transistor 35 and resistors 36, 37, and 38 is connected between the terminal 1 and a reference potential point. The base of the transistor 35 is connected to the terminal 1 via a resistor 39, and is also connected to a reference potential via a diode 40 and a Zener diode 41 which is a constant voltage element.
The bases of the transistors 31 and 32 are connected to the terminal 1 through a series circuit of a resistor 42 and a diode 43, and further connected to a reference potential point through a resistor 44. The collectors of the transistors 27 and 28 are connected to a reference potential point via resistors 45 and 46, and also to the bases of the transistors 47 and 48. The collector of the transistor 47 is connected to the terminal 1, the emitter is connected to the reference potential point via a resistor 49, and to the bases of the transistors 22, 23, 24, 25 via resistors 50, 51, 52, 53. The collector of the transistor 48 is connected to the terminal 1, the emitter is connected to a reference potential point via a resistor 54, and further connected to the bases of transistors 57 and 58 via resistors 55 and 56.
The emitters of transistors 57 and 58 are connected to a reference potential point, and the collectors are connected to flip-flops ' ₁ and ' ₂ of flip-flops 21b and 21c of mode switching circuit 21. These flip-flops 21b and 2
1c, Q ₁ , ₁ , Q ₂ , ₂ are lamp switching circuits 21
It is connected to the input terminal of a. Terminal 1 is applied to a switch mode switching circuit 59 via switches 60a, 60b, 60c, and 60d, and the four outputs of this switch mode switching circuit 59 are R ₁ , S ₁ , R ₂ , and S ₂ of flip-flops 21b and 21c. added to. Flip-flops 21b and 21c are constructed as shown in FIG.

Next, the operation of this circuit will be explained. When the power is turned on, the potential at terminal 1 remains at t ₄ as shown in Figure 3 for a certain period of time.
Afterwards, a constant DC voltage is reached. Therefore, resistance 26
The connection point between a and 26b has the characteristics shown in FIG. 3A. On the other hand, the characteristic of the voltage at the connection point between the resistors 36 and 37 increases until the constant voltage element 41 operates, as shown in FIG. 3B. Similarly, the voltage characteristics at the connection point between the resistors 37 and 38 are as shown in Figure 3c. The voltages of B and C become constant at time t ₁ and intersect with the voltage characteristics of A at times t ₂ and t ₃ .

Until time _t2, the potential at the bases of transistors 29 and 30 is higher than the potential at the bases of transistors 27 and 28, so transistors 27 and 28 are conductive.
The base potentials of transistors 47 and 48 become high level, and transistors 47 and 48 become conductive.
As a result, transistors 22, 23, 24, 25
conducts, transistors 3, 6, 9, 10, 1
Transistors 3, 16, 18, and 20 are cut off, and transistors 57 and 58 are also turned on.

Transistors 3, 6, 9, 10, 13, 16,
Since 18 and 20 are blocking, light emitting diode 2
Sufficient current does not flow through a, 2b, 2c, and 2d, so they do not light up. At this time, _Q'1 of the flip-flop 21b is 0, and _Q'2 of the flip-flop 21c is also 0. At this time, the switches 60a, 60
b, 60c, 60d are not pressed again, so R ₁ , S ₁ , R ₂ , of flip-flops 21b, 21c
All S ₂ are 0. Therefore flip-flop 2
1b, 21cQ ₁ becomes 1, ₁ becomes 0, Q ₂ becomes 0, ₂ becomes 1. As a result, the output terminals a, b, c, and d of the lamp switching circuit 21a are in the state of [1, 0, 0, 0]. Between time t ₂ and t ₃ , transistor 28
is cut off, and transistor 30 becomes conductive. As a result, transistor 48 is cut off and transistor 5
Since 7 and 58 are also blocked, flip-flop 21
The ' ₁ and Q' ₂ terminals of flip-flops 21b and 21c are open, and the outputs of flip-flops 21b and 21c maintain their previous states.

When terminals a, b, c, and d are [1, 0, 0, 0], 9 of transistors 9, 16, 6, and 13
However, since transistor 23 is conductive, transistor 9 is not actually turned on and light emitting diode 2a does not emit light. Between time t ₃ and t ₄ ,
Since transistor 27 is cut off and transistor 29 is turned on, transistors 22, 23, 24, 2
5 is cut off, and as a result, transistor 9 becomes conductive and light emitting diode 2a lights up. When the power is turned on in this way, switches 60a, 60b, 60
Light emitting diode 2a without operating c, 60d
The switching of the audio multiplexing circuit that is always issued by the flip-flops 21b and 21c is performed by the outputs Q ₁ , ₁ , Q ₂ ,
₂ .

When the switch 60b is pressed in this state, the output states of the flip-flops 21b and 21c change, and the outputs of the terminals a, b, c, and d become [0010]. As a result, transistor 9 is cut off, transistor 6 is turned on, and light emitting diode 2b emits light. Similarly, when the switches 60c and 60d are pressed, the light emitting diodes 2c and 2d emit light.

When the power is turned off, the potentials at points A, B, and C in FIG. 1 decrease in accordance with the characteristics A, B, and C in FIG. 3.

That is, in the period from _t3 to _t2 , the transistor 22,
Since 23, 24, and 25 are cut off, the light emitting diodes 2a, 2b, 2c, and 2d are turned off. If transistors 57 and 58 are transistors 22 and 2
If the light emitting diode 2b is turned on before the light emitting diode 3, 24, and 25, the light emitting diode 2b will turn off, and the light emitting diode 2a will emit light and then turn off, which is not preferable.

As described above, the present invention provides a plurality of light sources 2a, 2b,
2c, 2d, and any one of these multiple light sources
The first switching circuit 3, 6, 18, 9, 10, 13, 16, 1 sets the lights to a state where they can be lit.
8, 20, and a plurality of switches 60a, 60b, 60c, and 60d corresponding to the plurality of light sources, and a plurality of output states are created by the operation of these plurality of switches, and in this output state, the first switching circuit a mode switching circuit 21 which controls the light source corresponding to the activated switch to enable lighting; and a mode switching circuit 21 which operates with a constant voltage at the rise of the voltage when the power is turned on or the fall of the voltage when the power is turned off. , a second switching circuit 2 that sets the mode switching circuit to enter a specific mode state up to this constant voltage, and releases the specific mode state when the constant voltage is generated;
8, 30, 48, 57, and 58, the plurality of voltages are switched by the first switching circuit to a constant voltage higher than the constant voltage at the rise of the voltage when the power is turned on or the fall of the voltage when the power is turned off. A third circuit controls the light source so that it does not light up, and controls one of the plurality of light sources to ignite by the first switching circuit when this constant voltage is generated.
switching circuits 27, 29, 47, 22, 2
3, 24, and 25, it is possible to always turn on a predetermined light source among the plurality of light sources after the power is turned on, and when the power is turned off, unnecessary light sources are turned on momentarily. The light source lights up without any need to do so.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a light source control device according to an embodiment of the present invention, FIG. 2 is a specific circuit diagram of a part of the device, and FIG. 3 is a characteristic diagram for explaining the device. 1...DC power supply terminal, 2a, 2b, 2c, 2d
...Light emitting diode, 3, 6, 9, 10, 13,
16, 18, 20, 22, 23, 24, 25, 2
7, 28, 2930, 35, 47, 48, 57,
58... Transistor, 26a, 26b... Voltage dividing resistor, 41... Zener diode, 45, 4
6...Resistor, 21...Mode switching circuit, 21b,
21c...Flip-flop, 21a...Lamp switching circuit, 60a, 60b, 60c, 60d...
Switch.

Claims (1)

[Claims] 1. A plurality of light sources, a first switching circuit that sets any one of the plurality of light sources to a lighting-enabled state, a plurality of switches corresponding to the plurality of light sources, and a switch that operates according to the operation of the plurality of switches. a mode switching circuit that generates a plurality of output states, controls the first switching circuit in the output state, and sets the light source corresponding to the activated switch to a ready state; and a mode switching circuit that controls the voltage when the power is turned on. The switching operation is performed at a constant voltage at the rise or fall of the voltage when the power is cut off, and the mode switching circuit is set to be in a specific mode state until this constant voltage is reached, and when the constant voltage is raised, the mode switching circuit is set to be in the specific mode state. the plurality of light sources by the second switching circuit for releasing the light source and the first switching circuit to a certain voltage higher than the certain voltage at the rise of the voltage when the power is turned on or the fall of the voltage when the power is turned off. and a third switching circuit that controls the light source so that the light source does not light up, and controls the first switching circuit so that one of the plurality of light sources lights up when the constant voltage is generated. Light source control device.