JPS5933137Y2 - Amplifier speaker switching circuit - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a speaker switching circuit for an amplifier.

Conventionally, speaker switching circuits for large output amplifiers have used small current switches, power switches, relays, etc. for general electronic signal circuits, but these have had the following drawbacks.

(1) When using a switch for general electronic signal circuits, if the timing is bad and the switch is made at high output, the arc will fly off, damaging the contacts and causing poor contact, and in severe cases, they will weld and become inoperable.

(2) Using a power switch eliminates the problem described in (1), but it is expensive and the contacts are not self-cleaning, so contact failure is likely to occur when the current is small (small output).

(3) When a power switch is used, the operating force is generally large and unbalanced compared to other switches.

(4) If relays are used, the cost will be high;
When creating multiple circuits, a large space is required.

An object of the present invention is to provide a speaker switching circuit for an amplifier that solves the various drawbacks of the prior art as described above.

Now, FIG. 1 shows one embodiment of the switch device used in the speaker switching circuit of the present invention, and is a sectional view of the switch device constructed from a bush type switch.

As shown in FIG. 1, the button switch 1 has contact a.

It has a first switch S1 of one circuit and two contacts, which is composed of b1 common terminal C and switching contact piece d, and a second switch S2, which is composed of contact e1, common terminal f, and switching contact piece g.

When the lever 2 of the bushing type switch 1 is pressed, the changeover contacts d and g fixed to the shaft 3 move, and as a result, in the first switch Sl, conduction initially occurs between contacts a and e, and contact b
The one that was open between contacts b and c is conductive between contacts b and c, and the one that was open between contacts a and
At the same time, in conjunction with the first switch S1, in the second switch S2, the contacts e and f were initially open, but become conductive during the switching operation of the first switch S1, and the switching operation is completed. It is configured so that it can be opened again afterward.

FIG. 2 is an electrical connection diagram of the switch device shown in FIG. The timing of the opening and closing operations of the second switch S2, which is composed of the e1 common terminal f and the switching contact g, is set to the following conditions.

FIG. 3 is a time chart of the switch device shown in FIG.

In the figure, from the switching operation start time To to the switching operation completion time Te of the switching device, T2 is the time when the conduction between contacts a and C disappears, T3 is the time when the conduction between contacts b and c starts, and T3 is the time when the conduction between contacts b and c starts, and the time when the contact e is If the time when the conduction between contacts e and f starts to break is T1, and the time when the continuity between contacts e and f starts to break is T4, then T o (T 1 (T 2...)・・・
・・・・・・・・・・・・(1) TI<T3・・・・・・
・・・・・・・・・・・・・・・・・・(2) T 3
(T 4 (T e・・・・・・・・・・・・・・・
・・・・・・・・・(3) T2<T4・・・・・・・・・
・・・・・・・・・・・・・・・(4) Above (1)～(
The timing of the first switch S1 and the second switch S2 is adjusted so as to satisfy Equation 4).

That is, in FIG. 2, just before the contact a and the switching contact piece d of the first switch S1 are separated, the contact f and the switching contact piece g of the second switch S2 are connected, and the contact point of the first switch S1 is connected. Immediately after the switching contact d is connected, the contact f of the second switch S2 and the switching contact g are configured to separate.

Above, we have described an example in which the switch device used in the speaker switching circuit of the present invention is implemented as a bush type switch, but the timing of the switching operation of the two interlocking switches is configured so as to satisfy the above-mentioned requirements. It can be implemented with any type of switch, such as a rotary set or a slide type.

Next, an embodiment of an amplifier speaker switching circuit of the present invention constructed using the above switching device will be described.

FIG. 4 is a circuit diagram showing an embodiment of the present invention.

In the figure, a signal applied to an input terminal 41 is amplified by an amplifier 42, and then passed through a first switch S1 to a speaker S.
Supplied to P1.

The second switch S2 that is interlocked with the first switch S1 is
It is connected between amplifier 42 and ground.

In such a circuit, the timing of the first switch S1 and the second switch S2 is adjusted so that the above equations (1) to 0) are satisfied, and the first switch S1 is switched to the speaker switching circuit. For example, the second switch S2 closes immediately before the signal supply to the speaker SP1 is cut off by the first switch S1, and the input signal applied to the input terminal 41 flows to the ground side, so that the output side of the amplifier 42 becomes a no-current state.

Immediately after the first switch S1 switches to the speaker switching circuit, the second switch S2 opens again, so the input signal applied to the input terminal 41 flows to the amplifier 42 side, is amplified, and is supplied to the speaker SP2. Become so.

In this way, the output side of the amplifier 42 is in a no-current state during the switching operation, so even if the speaker is switched at high output, there is no risk of arcing or the like occurring in the first switch 81, and even a small current switch can be used. Can be used with high reliability.

Moreover, FIG. 5 is a circuit diagram showing another embodiment of the present invention, and is an example of application to a speaker switching circuit of a stereo amplifier.

In the figure, stereo signals applied to input terminals 51 and 52 are amplified by amplifiers 53 and 54, respectively, and passed through a first switch S1 and a third switch S, which performs the same switching operation as the first switch S1, to a speaker SP3. ．． SP4
is supplied to

Transistors Q1 . The collector terminals of Q2 are connected, and the bases are commonly connected and connected to the 10B power supply via the second switch S2 and resistor R1.

In this circuit, when the second switch S2 is closed, a 10B power supply is applied as a bias to the bases of the transistors Ql and Q20 via the resistor R1 and the second switch S2, and the transistors Q1 and Q2 become conductive, and the input terminal 5
1.52 The stereo signal applied to transistor Q1
．． Flows to the ground side via Q2.

Therefore, the output sides of the amplifiers 53 and 54 are in a no-current state, so that the first switch S1 and the third switch S3 can be switched safely.

Furthermore, FIG. 6 is a circuit diagram showing another embodiment of the present invention.

The large current signal is supplied to the load RL1 via the input terminal 61, the collector/emitter of the transistor Q3, and the first switch S1.

A resistor R2 is connected between the collector and base of the transistor Q3, and a series circuit of the resistor R3 and the second switch S2 is connected between the base and ground.

The values of the resistors R2 and R3 are set so that when the second switch S2 is closed, the transistor Q3 is turned off, and when the second switch S2 is opened, the transistor Q3 is turned on.

In such a configuration, the first switch S1 is connected to the load R
If an attempt is made to switch to the Lz side, the second switch S2 closes and the transistor Q3 becomes non-conductive. After the switching is completed, the second switch S2 opens and the transistor Q3 becomes conductive again, and the large current signal is transferred to the load RL2. is supplied to

In this case as well, since the switching operation of the first switch S1 is performed in a no-current state, it is possible to use a small current switch.

As described above, the amplifier speaker switching circuit of the present invention has the following effects.

(a) It becomes possible to switch large current circuits using general electronic signal circuit switches.

(b) When switching, it is possible to eliminate arcs that damage the contacts and shorten their lifespan.

(c) Since a general electronic signal circuit switch is used,
No contact failure occurs even with minute currents.

2) The operating force can be reduced compared to large current switches.

(E) The same effect can be obtained without using large current switches, relays, etc., resulting in a significant cost reduction.

(f) Manufacturing is easy because no special parts are used.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the switch device used in the speaker switching circuit of the present invention, FIG. 2 is an electrical connection diagram of the switch device shown in FIG. 1, and FIG. 3 is a cross-sectional view of the switch device shown in FIG. The time chart, FIG. 4, FIG. 5, and FIG. 6 are circuit diagrams each showing an embodiment of the speaker switching circuit of the present invention.

Claims (1)

[Scope of utility model registration request] an amplifier, first and second speakers, a first switch means for switchingly connecting the first or second speaker to the output end of the amplifier, and interlocking with the first switch means, for cutting off the input signal of the amplifier for a predetermined period of time from the time when the connection between the amplifier and one speaker is disconnected, and after a predetermined time after the time when the amplifier and the other speaker are connected; A speaker switching circuit for an amplifier, comprising a second switching means.