JPH0774665A - Amplifier with both ac/dc power supplies - Google Patents

Abstract

PURPOSE:To provide the amplifier for AC/DC power supply which can be used both in the AC power supply and the DC power supply. CONSTITUTION:An AC power supply circuit consisting of a transformer 3 which decends the ac voltage from the commercially available power supply, rectifier 4 rectifying and smoothing, capacitor C4, and regulator 5 for stabilization and a DC power supply circuit consisting of a relay 2 which is driven by the DC voltage supplied from an output terminal 9 and a contact 22 of the relay 2 which supplies the DC voltage to the output of the regulator 5 are provided in a booster 20. The power is supplied to the amplifier 1 from the circuit which has power from among the power supply circuits.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amplifier capable of operating with an AC power supply or a DC power supply, and is particularly suitable for application to a CATV booster installed indoors or outdoors. .

[0002]

2. Description of the Related Art Recently, a cable television system capable of avoiding a radio interference such as a ghost and transmitting image signals such as television broadcasts and movies in an area having a radio interference, a housing complex or an urban area. (CA
TV) is used. In order to join the CATV and receive a television broadcast, a movie, or the like, it is necessary to branch a signal from the CATV line that is stretched and lead the transmission line indoors.

In this case, the electric field of the TV signal propagating in the space may be stronger than the electric field received from the CATV line, for example, in the case of a strong electric field region. In such a case, it is called a front ghost. The ghost is generated by the signal that should be received. Further, since the line drawn from the CATV line indoors is further branched and connected to a plurality of TV receivers or the like, the electric field received from the CATV line may be insufficient and noise may be generated on the screen. . For this reason, using a booster, C
It has been conventionally practiced to amplify the signal from the ATV line and then pull the signal indoors, thereby preventing a front ghost and noise.

This pattern will be described with reference to FIGS. 4 and 5. FIG. 4 shows the case where the booster 102 is installed outdoors, and FIG. 5 shows the case where the booster 108 is installed indoors. Booster 1 as shown in FIG.
When 02 is installed outdoors, the booster 10 is installed by some means, because generally no outlet is provided outdoors.
2 must be powered. Therefore, it has been considered to supply power to the booster 102 indoors.

That is, the power is supplied as follows. Switch 1 inserted from the CATV line 100
The signal branched by 01 is supplied to the booster 102 via the protector 103. The signal amplified by the booster 102 travels along the lead-in line 104 and is drawn indoors to be input to the power supply unit 105. This power supply unit 105
Is a commercial power supply of AC100V, and the AC power supply that has been stepped down (for example, AC30V) is drawn into the lead-in line 10
4 to the booster 102.

In this way, the AC power source supplied to the booster 102 is converted into DC by the rectifying / smoothing means provided in the booster 102 and then supplied to the amplifier in the booster 102. Then, the signal from the CATV line 100 amplified by the amplifier in the booster 102 passes through the lead-in line 104 and the power supply unit 105 and is input to the home terminal 106 provided indoors as described above. From this home terminal 106 to T
A signal is supplied to the V receiver 107. It should be noted that the protector 103 is provided to prevent a TV receiver or the like installed indoors from being affected by a lightning or the like guided to the CATV line 100. This protector 103 is generally composed of an arrester.

Next, FIG. 5 shows a case where the booster 108 is installed indoors. In this case, as a matter of course, the power source is supplied to the booster 108 using the outlet of the commercial power source provided indoors. That is, the signal from the CATV line 100 is branched by the branching device 101 and drawn into the room through the protector 103. Then, it is amplified by the booster 108 installed indoors and input to the home terminal 106. AC 100V is supplied to the booster 108 from an outlet provided indoors.

Therefore, the power supply circuit provided in the booster 108 steps down, rectifies, and smoothes the supplied AC 100 V and supplies it to the amplifier provided in the booster 108. The home terminal 106
The image signal supplied from the CATV line 100 to the TV receiver 107 is displayed on the screen of the TV receiver 107.

[0009]

As shown in FIGS. 4 and 5, the power supply method differs depending on whether the booster is installed outdoors or indoors. It is necessary to prepare a booster with a product as a product, which requires different specifications,
There is a problem that the cost increases due to an increase in the number of parts. Therefore, an object of the present invention is to provide an AC / DC power supply type amplifier that can be used with an AC power supply or a DC power supply.

[0010]

In order to achieve the above object, the present invention is directed to an AC power supply unit for stepping down and rectifying and smoothing AC100V which is a commercial power supply, and a direct current sent from a room through a signal line. The power source is provided in the booster with a DC power source unit that can be switched so that the DC power source is automatically detected by the fact that the DC power source is being supplied.

[0011]

According to the present invention, since it is possible to use either an AC power supply or a DC power supply, it is not necessary to increase the number of products, so that the cost can be reduced by the effect of mass production. Further, since the supply of DC power is automatically detected and switched, it is possible to prevent misuse due to difference in power supply.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a booster of a first embodiment which is an AC / DC power supply type amplifier of the present invention. In the booster 20 shown in this figure, 8 is an input terminal to which a signal from the CATV line is input, and the signal input from this input terminal 8 is input to the amplifier 1 via the coupling capacitor C ₁ and the amplifier 1 Amplified and coupled capacitor C ₂
Is output from the output terminal 9 via. Power is supplied to the amplifier 1 from a power line.

First, the case where the booster 20 is installed indoors will be described. When the booster 20 is installed indoors, a commercial power supply AC100V is applied to the transformer 3, and a low AC voltage that is transformed by the transformer 3 and stepped down to the secondary side is output. This AC voltage is full-wave rectified by the full-wave rectifier _{4 and} smoothed by the capacitor C ₄ .
Further, the voltage across the capacitor C ₄ is stabilized by the regulator 5 and supplied to the amplifier 1 via the power supply line. The capacitor C ₃ connected to the output side of the regulator 5 is a capacitor for stabilizing the DC voltage. At this time, the contact 22 of the relay 2 is opened so that the smoothed voltage is not output from the output terminal 9.

Next, the case where the booster 20 is installed outdoors will be described. When the booster 20 is installed outdoors, the commercial AC power of AC100V supplied to the power supply unit 10 from the outlet provided indoors is the power supply unit 10.
Inside, the voltage is stepped down, rectified and smoothed, converted into a DC voltage, and then supplied to the output terminal 9 of the booster 20 via the line 11. The DC voltage supplied to the output terminal 9 is applied to the relay coil 21 of the relay 2 via the choke coil 6. Then, the relay coil 21
Is now energized by this DC voltage and the relay 2
The contact 22 of is closed. Therefore, the DC voltage applied to the output terminal 9 is supplied to the regulator 5 via the contact 22 and is stabilized, and then supplied to the amplifier 1. In this case, the DC voltage connected to the input side of the regulator 5 is not blocked by the full-wave rectifier 4 and applied to the transformer 3.

The line 11 is a line 11 through which the amplified signal output from the output terminal 9 is transmitted, and the signal passes through the power supply unit 10 and is supplied to a TV or the like. Alternatively, the signal may be supplied to the TV via the home terminal. Further, the choke coil 6 prevents the signal amplified by the amplifier 1 from being transmitted to the power supply side by utilizing the fact that the impedance of the inductance is high at high frequencies. Furthermore, the capacitor C ₂
Uses the fact that direct current does not pass, and prevents the direct current voltage supplied to the output terminal 9 from being applied to the amplifier 1. The lightning arrester 7 is composed of an arrester or the like and drops the lightning transmitted through the line 11 to the ground as its name suggests.

In the AC / DC power supply dual type amplifier shown in FIG. 1, when the booster 20 is operated by supplying DC power from the power supply unit 10 provided indoors, the booster 20 is erroneously supplied with a commercial power supply AC100V. When supplied, the AC voltage induced on the secondary side of the transformer 3 is full-wave rectified by the rectifier _{4 and} smoothed by the capacitor C ₄ . This smoothed voltage is applied to the relay coil 21 via the contact 22 of the relay 2 and is output from the output terminal 9 via the choke coil 6.

Therefore, even if the power supply unit 10 is turned off, the relay 2 continues to operate, so that the state in which the DC voltage is output to the output terminal 9 is maintained. In this case, if the output terminal 9 is short-circuited for some reason, the output terminal 9
Since the voltage is reduced, no current is supplied to the relay coil 21, and the relay 2 recovers, but an excessive short-circuit current may flow through the transformer 3 and the rectifier 4 before the relay 2 recovers, which may adversely affect them. Therefore, an embodiment of an AC / DC power supply / combined amplifier in which this drawback does not occur will be described below.

FIG. 2 shows an AC / DC power supply / combined type amplifier according to a second embodiment of the present invention. The AC / DC power supply dual-purpose amplifier shown in FIG. 2 is different from that shown in FIG. 1 in that the relay 2 is further provided with a second relay contact 23, and the second relay contact 23 is used as one output of the transformer 3. , And is connected to the rectifier 4. However, the second relay contact 23 is a contact that is closed when the relay 2 is not operating. In this way, when the second relay contact 23 is connected, the relay 2 operates when DC power is applied to the output terminal 9 as described above, and the contact 22 provided on the relay 2 is closed to The relay contact 23 of is opened. Therefore, the DC power supply is the regulator 5
, But the input side of the rectifier 4 is cut off by the second relay contact 23 connected between the rectifier 4 and the transformer 3.

Therefore, even if the AC power is erroneously supplied when the DC power is applied to the output terminal 9, the AC power is not applied to the rectifier 4, and the output of the rectifier 4 is applied to the relay coil 21 and the relay coil 21. The output to the output terminal 9 is prevented. When only the AC power source is applied, the second relay contact 23 is closed, so this AC power source is supplied to the rectifier 4, smoothed, and then stabilized by the regulator 5. The second embodiment of the present invention shown in FIG. 2 is similar in configuration and operation to the first embodiment of the present invention shown in FIG. 1 except for the points described above.
Description of other parts will be omitted.

Next, FIG. 3 shows a third embodiment of the AC / DC power supply type amplifier of the present invention. Compared to the second embodiment, the third embodiment is configured so that the contacts of the relay may be one circuit contact, and a low-cost general-purpose relay can be used. is there. This Figure 3
The AC / DC power supply dual-purpose amplifier shown in FIG. 2 is provided with a single circuit relay contact 24 instead of the relay contact 22 and the relay contact 23 of the relay 2 shown in FIG. The movable contact a and the fixed contact c of this relay contact 24
Is provided between the output of the rectifier 4 and the regulator 5, and the fixed contact b and the movable contact a are provided between the choke coil 6 and the regulator 5. However, the movable contact a and the fixed contact c of the relay contact 24 are normally closed contacts that are closed when the relay 2 is not operating, and the fixed contact b and the movable contact a are not operating the relay 2. It is a normally open contact that is sometimes open.

As described above, when the relay contact 24 is connected, the relay 2 is provided in the relay 2 because a current is supplied to the relay coil 21 to operate when a DC power source is applied to the output terminal 9 as described above. The movable contact a and the fixed contact b are closed, and the movable contact a and the fixed contact c are opened. Therefore, the DC power supplied to the output terminal 9 is applied to the input of the regulator 5, but the movable contact a and the fixed contact c of the relay contact 24 connected between the rectifier 4 and the regulator 5 cause the rectifier 4 to move. The output side of will be shut off.

Therefore, even if the AC power is erroneously supplied to the transformer 3 while the DC power is applied to the output terminal 9, the voltage obtained by rectifying the AC power by the rectifier 4 is not applied to the regulator 5. The output of the rectifier 4 can be prevented from being output to the relay coil 21 and the output terminal 9. When only the AC power is applied, the movable contact a and the fixed contact c of the relay contact 24 are closed. Therefore, the AC power is supplied to the rectifier 4 and smoothed, and then the regulator 5 is used. Stabilized. The third embodiment of the present invention shown in FIG. 3 is similar in configuration and operation to the first embodiment of the present invention shown in FIG. 1 except for the points described above, and therefore description of other parts will be omitted. And

As described above, according to the present invention, since the DC power source is supplied to the amplifier 1 by using the relay 2, there is almost no voltage drop as compared with the case where the electronic switch is used, and the power source can be effectively used. You can Further, the relay 2 has high reliability, is resistant to surges and has no polarity, and thus is easy to handle. Further, since the relay 2 does not need a circuit for driving the relay 2 in particular, it is not necessary to provide a drive circuit like an electronic switch. However, an electronic switch may be used instead of the relay 2 depending on the application.

In the above description, the present invention has been described as relating to an amplifier for CATV, but the present invention is not limited to this, and can be applied to a general amplifier installed outdoors or indoors. is there. Further, it is preferable to use a coaxial cable for the line for supplying a signal to the booster 20 shown in FIG. 1 and the line for outputting a signal.

[0025]

Since the AC / DC power supply type amplifier of the present invention is configured as described above, it can be used with either an AC power supply or a DC power supply, and it is necessary to prepare two types of products, one for AC and one for DC. Disappears. Therefore, the cost can be reduced due to the effect of mass production. Further, since the supply of the DC power supply is automatically detected and switched to the DC power supply, it is possible to prevent the different power supply from being erroneously supplied to the amplifier. If a relay is used for switching the DC power supply, the voltage drop of the switch can be made almost zero, and the power supply can be effectively used.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a first embodiment of an AC / DC power supply dual-purpose amplifier of the present invention.

FIG. 2 is a circuit diagram of a second embodiment of an AC / DC power supply / combined type amplifier of the present invention.

FIG. 3 is a circuit diagram of a third embodiment of an AC / DC power supply type amplifier of the present invention.

FIG. 4 is a diagram illustrating a power supply method when a conventional booster is installed outdoors.

FIG. 5 is a diagram illustrating a power supply method when a conventional booster is installed indoors.

[Explanation of symbols]

1 amplifier 2 relay 3 transformer 4 rectifier 5 regulator 6 choke coil 7 lightning arrester 8 input terminal 9 output terminal 10, 105 power supply section 11 line 21 relay coil 22, 23, 24 contacts 100 CATV line 101 branch device 102, 108 booster 103 protector 104 lead-in line 106 home terminal 107 TV receiver C ₁ , C ₂ coupling capacitor C ₃ stabilizing capacitor C ₄ smoothing capacitor

Claims (5)

[Claims] 1. An amplifier having an input terminal and an output terminal each connected to a signal line and inserted in series in the line, a power supply circuit for rectifying and smoothing an AC power supply to convert it into a DC power supply, and the amplifier. A relay operated by a DC power source supplied from one of the inserted signal lines, and when the AC power source is supplied, the AC power source is rectified and
Supply power from the power supply circuit to the amplifier after smoothing,
When the DC power is supplied, the relay operates to supply the DC power to the amplifier via the contact of the relay to the amplifier via the power supply circuit. Type amplifier. 2. The AC / DC power supply type amplifier according to claim 1, wherein the relay coil of the relay is connected to the signal line through a choke coil. 3. The power supply circuit is constituted by a rectifying / smoothing circuit and a constant voltage circuit, and a contact on the output side of the relay is connected to an input side of the constant voltage circuit. Alternatively, the AC / DC power supply combined type amplifier described in 2. 4. The relay is provided with a second contact, the second contact is connected to the input side of the rectifying / smoothing circuit, and the input side of the rectifying / smoothing circuit is shut off when the DC power is supplied. 4. The method according to claim 1, wherein
An AC / DC power supply dual-purpose amplifier according to any one of 1. 5. The relay is provided with one circuit contact consisting of a normally-closed contact and a normally-open contact, the normally-closed contact supplies power from the AC power supply side, and the normally-open contact provides power from the DC power supply side. The AC / DC power supply type amplifier according to any one of claims 1 to 3, wherein power is supplied to the amplifier.