JPH0332111Y2

JPH0332111Y2 -

Info

Publication number: JPH0332111Y2
Application number: JP1985147842U
Authority: JP
Priority date: 1985-09-27
Filing date: 1985-09-27
Publication date: 1991-07-08
Also published as: JPS6257432U

Description

【考案の詳細な説明】以下の順序で本考案を説明する。[Detailed explanation of the idea] The present invention will be explained in the following order.

Ａ産業上の利用分野Ｂ考案の概要Ｃ従来の技術Ｄ考案が解決しようとする問題点Ｅ問題点を解決するための手段（第１図）Ｆ作用Ｇ実施例 G₁ 回路構成 G₂ 回路動作Ｈ考案の効果Ａ産業上の利用分野この考案は、例えばテレビジヨン放送を受信す
る場合等に用いて好適な選局回路に関する。A. Field of industrial application B. Overview of the invention C. Conventional technology D. Problem that the invention aims to solve E. Means for solving the problem (Fig. 1) F. Effect G. Example G. ₁ circuit configuration G. ₂ circuit operation H Effects of the invention A Field of industrial application This invention relates to a channel selection circuit suitable for use, for example, in receiving television broadcasts.

Ｂ考案の概要この考案は、第１の電源が可動端子に供給され
る第１のスイツチの第１の固定端子を第１のトラ
ンジスタの主電極路を介してチユーナの第１の電
源端子に接続すると共に可変抵抗部及び１接点型
のスイツチ部からなる選局用可変抵抗器の上記ス
イツチ部を介して上記チユーナの第２の電源端子
に接続し、上記第１のスイツチの第２の固定端子
を上記チユーナの第３の電源端子に接続し、上記
第１のトランジスタの制御電極を第１のダイオー
ドを介して基準電源に接続し、第２の電源が可動
端子に供給される第２のスイツチの第１の固定端
子を第１の抵抗器を介して上記可変抵抗部の中間
端子に接続すると共に第２のダイオード及び第２
の抵抗器を介して上記可変抵抗部の一端に接続
し、上記第２のスイツチの第２の固定端子を第３
の抵抗器を介して上記可変抵抗部の一端に接続
し、この可変抵抗部の他端を第４の抵抗器を介し
て上記基準電源に接続すると共に上記可変抵抗部
の摺動端子を上記チユーナの制御電圧端子に接続
し、上記第１の抵抗器と上記可変抵抗部の中間端
子の接続点を第５の抵抗器及び第２のトランジス
タの主電極路を介して上記基準電源に接続し、上
記第２のトランジスタの制御電極を上記スイツチ
部の一端及び上記チユーナの第２の電極端子に接
続すると共に第３のダイオードを介して上記第１
のダイオードのカソード側にこの第１のダイオー
ドと極性が逆になるようにして接続して成る構成
とすることにより、トランジスタや抵抗器等の回
路部品の点数を削減し、低廉化、小型化を図るよ
うにしたものである。B. Summary of the invention This invention connects the first fixed terminal of the first switch, whose movable terminal is supplied with the first power, to the first power supply terminal of the tuner through the main electrode path of the first transistor. At the same time, it is connected to the second power terminal of the tuner through the switch section of a variable resistor for tuning consisting of a variable resistance section and a one-contact type switch section, and a second fixed terminal of the first switch. is connected to a third power supply terminal of the tuner, a control electrode of the first transistor is connected to a reference power supply via a first diode, and a second switch is connected to a movable terminal of the tuner. A first fixed terminal of the variable resistance section is connected to an intermediate terminal of the variable resistance section via a first resistor, and a second diode and a second
The second fixed terminal of the second switch is connected to one end of the variable resistance section through the resistor of the third switch.
The other end of the variable resistance section is connected to the reference power source via a fourth resistor, and the sliding terminal of the variable resistance section is connected to the tuner. and connecting a connection point between the first resistor and the intermediate terminal of the variable resistance section to the reference power supply via a fifth resistor and a main electrode path of the second transistor; A control electrode of the second transistor is connected to one end of the switch section and a second electrode terminal of the tuner, and the control electrode of the second transistor is connected to the first terminal via a third diode.
By connecting the first diode to the cathode side of the first diode so that the polarity is opposite to that of the first diode, the number of circuit components such as transistors and resistors can be reduced, resulting in lower cost and smaller size. This is what I tried to do.

Ｃ従来の技術従来の選局回路の一例として例えば第２図に示
すようなものがある。すなわち、第２図におい
て、１，２は夫々異なる正の電極＋V_B1，V_B2（＋
V_B1＜V_B2）が可動端子に供給されるバンド切換
スイツチであつて、スイツチ１，２が固定端子ａ
側に接続されるとVHF受信状態、固定端子ｂ側
に接続されるとUHF受信状態となる。スイツチ
１の固定端子ａはトランジスタ３のエミツターコ
レクタ路を介してチユーナ４の電源端子LB
（VHFのローチヤンネル用電源端子）に接続され
ると共にトランジスタ５のエミツターコレクタ路
を介してチユーナ４の電源端子HB（VHFのハイ
チヤンネル用電源端子）に接続される。トランジ
スタ３，５のエミツタ−ベース間には夫々抵抗器
６，７が接続される。スイツチ１の固定端子ｂは
チユーナ４の電源端子UB（UHF用電源端子）に
接続されると共にトランジスタ８のベースに接続
される。C. Prior Art An example of a conventional channel selection circuit is shown in FIG. 2, for example. That is, in FIG. 2, 1 and 2 are different positive electrodes +V _B1 and V _B2 (+
V _B1 <V _B2 ) is supplied to the movable terminal, and switches 1 and 2 are supplied to the fixed terminal a.
When connected to the side, it is in VHF reception mode, and when connected to the fixed terminal b side, it is in UHF reception mode. The fixed terminal a of the switch 1 is connected to the power supply terminal LB of the tuner 4 via the emitter-collector path of the transistor 3.
(VHF low channel power supply terminal) and is also connected to the tuner 4's power supply terminal HB (VHF high channel power supply terminal) via the emitter-collector path of transistor 5. Resistors 6 and 7 are connected between the emitters and bases of transistors 3 and 5, respectively. A fixed terminal b of the switch 1 is connected to the power supply terminal UB (UHF power supply terminal) of the tuner 4 and also to the base of the transistor 8.

スイツチ２の固定端子ａは抵抗器９、可変抵抗
器１０及びトランジスタ１１のコレクタ−エミツ
タ路を介して接地されると共にダイオード１２及
び可変抵抗器１３を介して可変抵抗部１４及び２
接点型スイツチ部１５から成る選局毛可変抵抗器
１６の可変抵抗部１４の一端に接続される。可変
抵抗部１４とスイツチ部１５の各摺動端子は連動
し、可変抵抗部１４は中間端子を中心としてその
上側摺動部はVHFのハイチヤンネルのとき使用
され、その下側摺動部はVHFのローチヤンネル
のとき使用され、またスイツチ部１５はその摺動
端子がVHFのハイチヤンネルのときは上側接点
に接続され、VHFのローチヤンネルのときは下
側接点に接続される。スイツチ２の固定端子ｂは
可変抵抗器１７を介して可変抵抗部１４の一端に
接続される。 A fixed terminal a of the switch 2 is grounded via a resistor 9, a variable resistor 10, and a collector-emitter path of a transistor 11, and is connected via a diode 12 and a variable resistor 13 to variable resistors 14 and 2.
It is connected to one end of the variable resistance section 14 of a tuning hair variable resistor 16 comprising a contact type switch section 15 . The sliding terminals of the variable resistance section 14 and the switch section 15 are interlocked, and the upper sliding section of the variable resistance section 14 is used for VHF high channel, centering on the intermediate terminal, and the lower sliding section is used for VHF high channel. When the sliding terminal is a low channel of VHF, the switch part 15 is connected to the upper contact, and when the sliding terminal is a low channel of VHF, it is connected to the lower contact. A fixed terminal b of the switch 2 is connected to one end of the variable resistance section 14 via a variable resistor 17.

可変抵抗部１４の摺動端子はチユーナ４の制御
電圧端子VC（図示せずも可変容量素子に選局周波
数に応じて異なる制御電圧が与えられるようにな
されている）に接続され、可変抵抗部１４の他端
は接続器１８及びトランジスタ８のコレクタ−エ
ミツタ路を介して接地されると共に抵抗器１９を
介して接地され、可変抵抗部１４の中間端子は並
列接続の可変抵抗器２２及びダイオード２３（逆
向き）を介してトランジスタ１１のコレクタ側に
接続される。スイツチ部１５の一端は抵抗器２０
を介してトランジスタ５のベースに接続され、ス
イツチ部１５の摺動端子は接地され、スイツチ部
１５の他端は抵抗器２１を介してトランジスタ３
のベースに接続される。 The sliding terminal of the variable resistance section 14 is connected to the control voltage terminal VC of the tuner 4 (a variable capacitance element, not shown, is configured to be given a different control voltage depending on the tuning frequency), and the variable resistance section The other end of the variable resistor 14 is grounded via a connector 18 and the collector-emitter path of the transistor 8, and is also grounded via a resistor 19, and the intermediate terminal of the variable resistor 14 is connected to a variable resistor 22 and a diode 23 connected in parallel. (in the opposite direction) to the collector side of the transistor 11. One end of the switch section 15 is a resistor 20
The sliding terminal of the switch section 15 is grounded, and the other end of the switch section 15 is connected to the base of the transistor 3 via a resistor 21.
connected to the base of

いま、VHFのローチヤンネルの受信時にはス
イツチ１，２が接点ａ側に切換わると共にスイツ
チ部１５が下側接点に接続される。すると、トラ
ンジスタ３がオンし、正の電源＋V_B1がチユーナ
４の電源端子LBに供給される。スイツチ２の固
定端子ａに与えられる正の電源＋V_B2より電流が
ダイオード１２−可変抵抗器１３−可変抵抗部
（全摺動部）−抵抗器１９の系路で流れると共に抵
抗器９−可変抵抗器１０−ダイオード２３−可変
抵抗部１４の中間端子−可変抵抗部１４の下側摺
動部−抵抗器１９の系路で流れる。従つて、可変
抵抗部１４の下側摺動部の範囲内でその摺動端子
を動かすことによりチユーナ４の制御電圧端子
VCに対応した制御電圧が供給され、これにより
所要の選局が可能となる。そしてこのVHFのロ
ーチヤンネル受信時の制御電圧のスタート電圧は
抵抗器１９により設定され、エンド電圧は可変抵
抗器１５によつて設定される。 Now, when receiving the VHF low channel, switches 1 and 2 are switched to the contact a side, and the switch section 15 is connected to the lower contact. Then, the transistor 3 is turned on, and the positive power supply +V _B1 is supplied to the power supply terminal LB of the tuner 4. Current flows from the positive power supply +V _B2 applied to the fixed terminal a of the switch 2 through the diode 12 - variable resistor 13 - variable resistor part (all sliding parts) - resistor 19, and at the same time, the current flows through the diode 12 - variable resistor 13 - variable resistor section (all sliding parts) - resistor 19. The current flows through the path of the resistor 10 - the diode 23 - the intermediate terminal of the variable resistance section 14 - the lower sliding part of the variable resistance section 14 - the resistor 19. Therefore, by moving the sliding terminal within the range of the lower sliding portion of the variable resistance section 14, the control voltage terminal of the tuner 4 can be adjusted.
A control voltage corresponding to the VC is supplied, thereby making it possible to select the desired channel. The start voltage of the control voltage when receiving the VHF low channel is set by a resistor 19, and the end voltage is set by a variable resistor 15.

また、VHFのハイチヤンネルの受信時にはス
イツチ１，２が接点ａ側に接続されたまゝの状態
でスイツチ部１５が上側接点に切換わり、これに
よりトランジスタ３がオフすると共にトランジス
タ５がオンし、正の電源＋V_B1がチユーナ４の電
源端子HBに供給される。またトランジスタ５の
オンによりトランジスタ１１もオンするようにな
る。スイツチ２の固定端子ａに与えられる正の電
源＋V_B2より電流がダイオード１２−可変抵抗器
１３−可変抵抗部１４（全摺動部）−抵抗器１９
の系路で流れると共に抵抗器９−可変抵抗器１０
−トランジスタ１１のコレクタ−エミツタ路の系
路で流れる。また、このとき可変抵抗器２２は可
変抵抗部１４の下側摺動部と抵抗器１９の直列回
路に並列接続されることになる。従つて、可変抵
抗部１４の上側摺動部の範囲内でその摺動端子を
動かすことによりチユーナ４の制御電圧端子VC
に対応した制御電圧が供給され、これにより所要
の選局が可能となる。そしてこのVHFのハイチ
ヤンネル受信時の制御電圧のスタート電圧は可変
抵抗器２２で設定され、エンド電圧は可変抵抗器
１３で設定される。 Furthermore, when receiving the VHF channel, the switch section 15 switches to the upper contact while switches 1 and 2 remain connected to the contact a side, which turns off the transistor 3 and turns on the transistor 5. The power supply +V _B1 is supplied to the power supply terminal HB of the tuner 4. Further, when transistor 5 is turned on, transistor 11 is also turned on. From the positive power supply +V _B2 applied to fixed terminal a of switch 2, current flows through diode 12 - variable resistor 13 - variable resistor section 14 (all sliding parts) - resistor 19
flows in the path of resistor 9-variable resistor 10.
- flows through the collector-emitter path of transistor 11; Further, at this time, the variable resistor 22 is connected in parallel to the series circuit of the lower sliding part of the variable resistance section 14 and the resistor 19. Therefore, by moving the sliding terminal within the range of the upper sliding portion of the variable resistance section 14, the control voltage terminal VC of the tuner 4 can be adjusted.
A control voltage corresponding to the channel is supplied, thereby making it possible to select the desired channel. The start voltage of the control voltage when receiving the VHF high channel is set by the variable resistor 22, and the end voltage is set by the variable resistor 13.

また、UHFの受信時にはスイツチ１，２が接
点ｂ側に切換えられ、これにより正の電源＋V_B1
がチユーナ４の電源端子UBに供給されると共に
トランジスタ８がオンし、トランジスタ３，５及
び１１はオフとなる。スイツチ２の固定端子ｂに
与えられる正の電源＋V_B2より電流が可変抵抗器
１７及び可変抵抗部１４（全摺動部）を通り、更
に抵抗器１９と抵抗器１８及びトランジスタ８の
コレクタ−エミツタ路の並列回路を介して流れ
る。従つて、可変抵抗部１４の全摺動部の範囲内
でその摺動端子を動かすことによりチユーナ４の
制御電圧VCに対応した制御電圧が供給され、こ
れにより所要の選局が可能となる。このUHFの
受信時の制御電圧のスタート電圧は抵抗器１８及
び１９により設定され、エンド電圧は可変抵抗器
１７で設定される。 Also, when receiving UHF, switches 1 and 2 are switched to the contact b side, which causes the positive power supply +V _B1
is supplied to the power supply terminal UB of tuner 4, transistor 8 is turned on, and transistors 3, 5 and 11 are turned off. Current flows from the positive power supply +V _B2 applied to the fixed terminal b of the switch 2 through the variable resistor 17 and the variable resistor section 14 (all sliding sections), and then between the resistor 19, the resistor 18, and the collector-emitter of the transistor 8. Flows through parallel circuits. Therefore, by moving the sliding terminal within the range of the entire sliding portion of the variable resistance section 14, a control voltage corresponding to the control voltage VC of the tuner 4 is supplied, thereby making it possible to select a desired channel. The start voltage of the control voltage during UHF reception is set by resistors 18 and 19, and the end voltage is set by variable resistor 17.

Ｄ考案が解決しようとする問題点ところが、上述の如き構成を成す従来回路の場
合、VHFのローチヤンネルとハイチヤンネルの
切換えはトランジスタ３及び５を用いて行い、ま
たUHFへの切換え時トランジスタ８をオンして
抵抗器１８を抵抗器１９に並列接続してVHF受
信時の制御電圧のスタート電圧を調整するように
しているので、部品点数が多く回路構成が複雑と
なり、コスト的に高価になると共に、小型化が困
難である等の欠点があつた。D Problems to be solved by the invention However, in the case of the conventional circuit configured as described above, switching between VHF low channel and high channel is performed using transistors 3 and 5, and when switching to UHF, transistor 8 is used. Since the start voltage of the control voltage during VHF reception is adjusted by turning on the resistor 18 and connecting it in parallel with the resistor 19, the number of parts is large and the circuit configuration is complicated, which increases the cost. However, it had drawbacks such as difficulty in miniaturization.

また、選局用可変抵抗器１６のスイツチ部１５
に２接点型を用いると、２接点を形成する銀の経
時変化による成長のために２接点間が接触するよ
うになるいわゆるマイグレーシヨン現象を生ずる
が、このために両接点に夫々カーボンを被せるな
どの対策を施すと、接点と摺動端子（可動端子）
の間の接触抵抗が増大し、これに伴つて接触抵抗
を流れる電流による電圧降下が増大し、この結果
減電圧に弱く、特に、低電圧駆動のセツトでは問
題であつた。 In addition, the switch section 15 of the variable resistor 16 for channel selection
When a two-contact type is used, a so-called migration phenomenon occurs in which the two contacts come into contact due to the growth of the silver that forms the two contacts over time. When measures are taken, contacts and sliding terminals (movable terminals)
The contact resistance between the two increases, and the voltage drop due to the current flowing through the contact resistance increases.As a result, the contact resistance is susceptible to voltage reduction, which is particularly a problem in low-voltage drive sets.

更にVHFのハイチヤンネルの使用時、制御電
圧に寄与する可変抵抗部１４側を流れる電流の外
に、制御電圧には無関係な大きな電流（約1mA
程度）が抵抗器９、可変抵抗器１０及びトランジ
スタ１１のコレクタ−エミツタ路を介して流れて
いるので、無駄な電流が多く消費電力が大きくな
り、バツテリーの寿命時間を短縮させる等の欠点
があつた。 Furthermore, when using the VHF high channel, in addition to the current flowing through the variable resistor 14 side that contributes to the control voltage, there is also a large current (approximately 1 mA) that is unrelated to the control voltage.
Since the current flows through the collector-emitter path of the resistor 9, the variable resistor 10, and the transistor 11, there are disadvantages such as a large amount of wasted current, increased power consumption, and shortened battery life. Ta.

この考案は斯る点に鑑みてなされたもので、部
品点数を低減できると共に、減電圧や消費電力の
問題を解消することができる選局回路を提供する
ものである。 This invention was made in view of these points, and aims to provide a channel selection circuit that can reduce the number of parts and solve the problems of voltage reduction and power consumption.

Ｅ問題点を解決するための手段この考案による選局回路は第１の電源＋V_B1が
可動端子に供給される第１のスイツチ１の第１の
固定端子ａを第１のトランジスタ３の主電極路を
介してチユーナ４の第１の電源端子LBに接続す
ると共に可変抵抗部１４及び１接点型のスイツチ
部１５′からなる選局用可変抵抗器１６′の上記ス
イツチ部１４を介して上記チユーナ４の第２の電
源端子HBに接続し、上記第１のスイツチ１の第
２の固定端子ｂを上記チユーナ４の第３の電源端
子UBに接続し、上記第１のトランジスタ３の制
御電極を第１のダイオード２５を介して基準電源
（アース）に接続し、第２の電源＋V_B2が可動端
子に供給される第２のスイツチ２の第１の固定端
子ａを第１の抵抗器２４を介して上記可変抵抗部
１４の中間端子に接続すると共に第２のダイオー
ド１２及び第２の抵抗器１３を介して上記可変抵
抗部１４の一端に接続し、上記第２のスイツチ２
の第２の固定端子ｂを第３の抵抗器１７を介して
上記可変抵抗部１４の一端に接続し、この可変抵
抗部１４の他端を第４の抵抗器１９を介して上記
基準電源に接続すると共に上記可変抵抗部１４の
摺動端子を上記チユーナ４の制御電圧端子VCに
接続し、上記第１の抵抗器２４と上記可変抵抗部
１４の中間端子の接続点を第５の抵抗器２２及び
第２のトランジスタ１１の主電極路を介して上記
基準電源に接続し、上記第２のトランジスタ１１
の制御電極を上記スイツチ部１５′の一端及び上
記チユーナ４の第２の電源端子HBに接続すると
共に第３のダイオード２６を介して上記第１のダ
イオード２５のカソード側にこの第１のダイオー
ド２５と極性が逆になるようにして接続するよう
構成している。E. Means for Solving Problems The channel selection circuit according to this invention connects the first fixed terminal a of the first switch 1, whose movable terminal is supplied with the first power supply +V _B1 , to the main electrode of the first transistor 3. The tuner is connected to the first power supply terminal LB of the tuner 4 through the channel, and is connected to the tuner 4 through the switch section 14 of the variable resistor 16' for tuning, which is composed of a variable resistor section 14 and a one-contact switch section 15'. The second fixed terminal b of the first switch 1 is connected to the third power terminal UB of the tuner 4, and the control electrode of the first transistor 3 is connected to the second power terminal HB of the first transistor 3. The first fixed terminal a of the second switch 2 is connected to the reference power supply (earth) through the first diode 25, and the second power supply +V _B2 is supplied to the movable terminal. The second switch 2
The second fixed terminal b of is connected to one end of the variable resistance section 14 through a third resistor 17, and the other end of this variable resistance section 14 is connected to the reference power source through a fourth resistor 19. At the same time, the sliding terminal of the variable resistance section 14 is connected to the control voltage terminal VC of the tuner 4, and the connection point between the first resistor 24 and the intermediate terminal of the variable resistance section 14 is connected to a fifth resistor. 22 and the main electrode path of the second transistor 11 to the reference power supply, and the second transistor 11
The control electrode of the first diode 25 is connected to one end of the switch section 15' and the second power supply terminal HB of the tuner 4, and the first diode 25 is connected to the cathode side of the first diode 25 via the third diode 26. It is configured to connect with the polarity reversed.

Ｆ作用 VHFのローチヤンネル受信時にはスイツチ１
が接点ａ側に切換つてトランジスタ３がオンし、
これによりチユーナ４の電源端子LBに第１の電
源＋V_B1が与えられ、また、スイツチ２が接点ａ
側に切換つて、第２の電源＋V_B2に基づいて選局
用可変抵抗器１６′の可変抵抗部１４の下側摺動
部に関連した制御電圧がチユーナ４の制御電圧端
子VCに供給される。F Effect Switch 1 when receiving VHF roach channel.
switches to contact a side, transistor 3 turns on,
As a result, the first power supply +V _B1 is applied to the power supply terminal LB of the tuner 4, and the switch 2 is connected to the contact a.
The control voltage associated with the lower sliding part of the variable resistance section 14 of the tuning variable resistor 16' is supplied to the control voltage terminal VC of the tuner 4 based on the second power supply +V _B2 . .

また、VHFのハイチヤンネル受信時にはスイ
ツチ１が接点ａ側に切換わると共に選局用可変抵
抗器１６′のスイツチ部１５′が（上側）接点に接
続され、これによりトランジスタ３がオフになる
と共に、チユーナ４の電源端子HBに第１の電源
＋V_B1が与えられ、また、スイツチ２が接点ａ側
に切換わつて、第２の電源＋V_B2に基づいて選局
用可変抵抗器１６′の可変抵抗部１４の上側摺動
部に関連した制御電圧がチユーナ４の制御電圧端
子VCに供給される。 Further, when receiving the VHF high channel, the switch 1 is switched to the contact a side, and the switch part 15' of the channel selection variable resistor 16' is connected to the (upper side) contact, thereby turning off the transistor 3, and The first power supply +V _B1 is applied to the power supply terminal HB of the tuner 4, and the switch 2 is switched to the contact a side, and the variable resistance of the tuning variable resistor 16' is changed based on the second power supply +V _B2 . A control voltage associated with the upper sliding part of the section 14 is supplied to a control voltage terminal VC of the tuner 4.

更に、UHF受信時には、スイツチ１が接点ｂ
側に接続されて、これによりチユーナ４の電源端
子UBに第１の電源＋V_B1が与えられ、またスイ
ツチ２が接点ｂ側に接続されて、第２の電源＋
V_B2に基づいて選局用可変抵抗器１６′の可変抵
抗部１４の全摺動部に関連して制御電圧がチユー
ナ４の制御電圧端子VCに供給される。 Furthermore, when receiving UHF, switch 1 is connected to contact b.
The switch 2 is connected to the contact b side, thereby giving the first power supply +V _B1 to the power terminal UB of the tuner 4, and the switch 2 is connected to the contact b side, giving the second power supply +V B1 to the power terminal UB of the tuner 4.
Based on V _B2 , a control voltage is supplied to the control voltage terminal VC of the tuner 4 in relation to all the sliding parts of the variable resistance section 14 of the tuning variable resistor 16'.

斯る構成により部品点数が削減され、また減電
圧に強く、しかも消費電力が小さくなる。 Such a configuration reduces the number of parts, is resistant to voltage reduction, and consumes less power.

Ｇ実施例以下、この考案の一実施例を第１図に基づいて
詳しく説明する。なお、同図において、第２図と
対応する部分には同一符号を付し、その詳細説明
は省略する。G. Example Hereinafter, an example of this invention will be described in detail based on FIG. 1. In this figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

G₁ 回路構成本実施例では、第１の電源＋V_B1が可動端子に
供給される第１のスイツチすなわちバンド切換ス
イツチ１の第１の固定端子ａを第１のトランジス
タ３の主電極路すなわちエミツタ−コレクタ路を
介してチユーナ４の第１の電源端子すなわち
VHFのローチヤンネル用電源端子LBに接続する
と共に可変抵抗部１４及び１接点型のスイツチ部
１５′からなる選局用可変抵抗器１６′のスイツチ
部１５′を介してチユーナ４の第２の電源端子す
なわちVHFのハイチヤンネル用電源端子HBに
接続する。なお、本実施例ではスイツチ部１５′
は第２図に破線で示すようにVHFのローチヤン
ネルに対応する下側接点はなく、VHFのハイチ
ヤンネルに対応する上側接点のみを有する１接点
型である。また、スイツチ１の第２の固定端子ｂ
をチユーナ４の第３の電源端子すなわちUHF用
電源端子UBに接続し、トランジスタ３の制御電
極を第１のダイオード２５及び抵抗器２１を介し
て基準電源（アース）に接続する。 _G1 Circuit Configuration In this embodiment, the first switch, that is, the first fixed terminal a of the band changeover switch 1, to which the first power supply +V _B1 is supplied to the movable terminal, is connected to the main electrode path of the first transistor 3, that is, the emitter. - the first power supply terminal of the tuner 4 via the collector path, i.e.
The second power source for the tuner 4 is connected to the VHF low channel power supply terminal LB and connected to the switch section 15' of the variable resistor 16' for tuning, which is composed of the variable resistor section 14 and the one-contact switch section 15'. Connect to the VHF Haiti channel power supply terminal HB. In addition, in this embodiment, the switch section 15'
As shown by the broken line in FIG. 2, it is a one-contact type that has no lower contact corresponding to the VHF low channel, but only an upper contact corresponding to the VHF low channel. In addition, the second fixed terminal b of the switch 1
is connected to the third power supply terminal of the tuner 4, that is, the UHF power supply terminal UB, and the control electrode of the transistor 3 is connected to the reference power supply (ground) via the first diode 25 and the resistor 21.

第２の電源＋V_B2が可動端子に供給される第２
のスイツチすなわちバンド切換スイツチ２の第１
の固定端子ａを第１の抵抗器すなわち可変抵抗器
２４を介して可変抵抗部１４の中間端子に接続す
ると共に第２のダイオード１２及び第２の抵抗器
すなわち可変抵抗器１３を介して可変抵抗部１４
の一端に接続する。また、スイツチ２の第２の固
定端子ｂを第３の抵抗器すなわち可変抵抗器１７
を介して可変抵抗部１４の一端に接続し、この可
変抵抗部の他端を第４の抵抗器１９を介して基準
電源に接続すると共に可変抵抗部１４の摺動端子
をチユーナ４の制御電圧端子VCに接続する。更
に抵抗器２４と可変抵抗部１４の中間端子の接続
点を第５の抵抗器すなわち可変抵抗器２２及び第
２のトランジスタ１１の主電極路すなわちコレク
タ−エミツタ路を介して基準電源に接続し、トラ
ンジスタ１１の制御電極をスイツチ部１５′の一
端及びチユーナ４の電源端子HBに接続すると共
に第３のダイオード２６を介してダイオード２５
のカソード側にこのダイオード２５と極性が逆に
なるようにして接続する。なお、ダイオード２
５，２６は１つのチツプに形成され得るものであ
る。 A second power supply +V _B2 is supplied to the movable terminal.
, that is, the first switch of band changeover switch 2.
The fixed terminal a of is connected to the intermediate terminal of the variable resistance section 14 via the first resistor, that is, the variable resistor 24, and the variable resistance is connected via the second diode 12 and the second resistor, that is, the variable resistor 13. Part 14
Connect to one end of the In addition, the second fixed terminal b of the switch 2 is connected to a third resistor, that is, a variable resistor 17.
The other end of the variable resistance section is connected to the reference power source via the fourth resistor 19, and the sliding terminal of the variable resistance section 14 is connected to the control voltage of the tuner 4. Connect to terminal VC. Furthermore, the connection point between the intermediate terminal of the resistor 24 and the variable resistor section 14 is connected to a reference power source via the fifth resistor, that is, the variable resistor 22, and the main electrode path, that is, the collector-emitter path of the second transistor 11; The control electrode of the transistor 11 is connected to one end of the switch section 15' and the power supply terminal HB of the tuner 4, and the control electrode of the transistor 11 is connected to the diode 25 via the third diode 26.
The diode 25 is connected to the cathode side of the diode 25 so that its polarity is opposite to that of the diode 25. In addition, diode 2
5 and 26 can be formed into one chip.

G₂ 回路動作次にこの第１図の回路動作を説明する。 _G2 Circuit Operation Next, the operation of the circuit shown in FIG. 1 will be explained.

VHFのローチヤンネルの受信時にはスイツチ
１，２が接点ａ側に切換わると共にスイツチ部１
５′が（上側）接点より解放されて何も接点のな
い所に位置するようになる。すると、トランジス
タ３がオンし、正の電極＋V_B1がチユーナ４の電
源端子LBに供給される。スイツチ２の固定端子
ａに与えられる正の電源＋V_B2より電流がダイオ
ード１２−可変抵抗器１３−可変抵抗部１４（全
摺動部）−抵抗器１９の系路で流れると共に可変
抵抗器２４−可変抵抗部１４の下側摺動部−抵抗
器１９の系路で流れる。従つて、可変抵抗部１４
の下側摺動部の範囲内でその摺動端子を動かすこ
とによりチユーナ４の制御電圧端子VCに対応し
た制御電圧が供給され、これにより所要の選局が
可能となる。そして、このVHFのローチヤンネ
ル受信時の制御電圧のスタート電圧は抵抗器１９
により設定され、エンド電圧は可変抵抗器２４に
より設定される。なお、抵抗器１９の抵抗値は、
可変抵抗器１３と可変抵抗部１４の上側摺動部の
抵抗値と可変抵抗器２４の抵抗値の並列合成値よ
り十分小さな値とされており、これによりチユー
ニング電圧のバラツキや抵抗値のバラツキの影響
を受けることがなくなる。 When receiving VHF low channel, switches 1 and 2 switch to contact a side, and switch part 1
5' is released from the (upper) contact and is located where there is no contact. Then, the transistor 3 is turned on, and the positive electrode +V _B1 is supplied to the power supply terminal LB of the tuner 4. Current flows from the positive power supply +V _B2 applied to the fixed terminal a of the switch 2 through the diode 12 - variable resistor 13 - variable resistor section 14 (all sliding parts) - resistor 19, and also flows through the variable resistor 24 - The current flows through the path between the lower sliding portion of the variable resistance section 14 and the resistor 19 . Therefore, the variable resistance section 14
By moving the sliding terminal within the range of the lower sliding portion of the tuner 4, a control voltage corresponding to the control voltage terminal VC of the tuner 4 is supplied, thereby enabling desired tuning. The start voltage of the control voltage when receiving this VHF low channel is connected to the resistor 19.
The end voltage is set by the variable resistor 24. Note that the resistance value of the resistor 19 is
The value is sufficiently smaller than the parallel composite value of the resistance value of the upper sliding part of the variable resistor 13 and the variable resistor section 14, and the resistance value of the variable resistor 24, thereby reducing variations in tuning voltage and resistance value. will no longer be affected.

また、VHFのハイチヤンネルの受信時にはス
イツチ１，２が接点ａ側に接続されたまゝの状態
でスイツチ部１５′が（上側）接点に切換わり、
これによりトランジスタ３がオフすると共にトラ
ンジスタ１１がオンし、正の電源＋V_B1がチユー
ナ４の電源端子HBに供給される。スイツチ２の
固定端子ａに与えられる正の電源＋V_B2より電流
がダイオード１２−可変抵抗器１３−可変抵抗部
１４（全摺動部）−抵抗器１９の系路で流れると
共に可変抵抗器２４−可変抵抗部１４の下側摺動
部−抵抗器１９の系路及び可変抵抗器２４−可変
抵抗器２２−トランジスタ１１のコレクタ−エミ
ツタ路の系路を流れる。従つて、可変抵抗部１４
の上側摺動部の範囲内でその摺動端子を動かすこ
とによりチユーナ４の制御電圧端子VCに対応し
た制御電圧が供給され、これにより所要の選局が
可能となる。そしてこのVHFのハイチヤンネル
受信時の制御電圧のスタート電圧は可変抵抗器２
２で設定され、エンド電圧は可変抵抗器１３で設
定される。このVHFのハイチヤンネル受信時、
可変抵抗器２４及び２２を介してトランジスタ１
１側に流れる電流は上述の如く可変抵抗器２４が
大きい値に設定されていので小さく、従つて無駄
な電流の消費が少ない。 Also, when receiving the VHF Haiti channel, the switch 15' switches to the (upper) contact while switches 1 and 2 remain connected to the contact a side.
As a result, the transistor 3 is turned off and the transistor 11 is turned on, and the positive power supply +V _B1 is supplied to the power supply terminal HB of the tuner 4. Current flows from the positive power supply +V _B2 applied to the fixed terminal a of the switch 2 through the diode 12 - variable resistor 13 - variable resistor section 14 (all sliding parts) - resistor 19, and also flows through the variable resistor 24 - It flows through the lower sliding part of the variable resistance section 14 - the resistor 19 path and the variable resistor 24 - variable resistor 22 - collector-emitter path of the transistor 11 . Therefore, the variable resistance section 14
By moving the sliding terminal within the range of the upper sliding portion of the tuner 4, a control voltage corresponding to the control voltage terminal VC of the tuner 4 is supplied, thereby enabling desired tuning. The start voltage of the control voltage when receiving this VHF Haiti channel is set by variable resistor 2.
2, and the end voltage is set by a variable resistor 13. When receiving this VHF Haiti channel,
Transistor 1 via variable resistors 24 and 22
The current flowing to the 1 side is small because the variable resistor 24 is set to a large value as described above, and therefore unnecessary current consumption is small.

また、VHFの受信時にはスイツチ１，２が接
点ｂ側に切換えられ、これにより正の電源＋V_B1
がチユーナ４の電源端子UBに供給される。スイ
ツチ２の固定端子ｂに与えられる正の電源＋V_B2
より電流が可変抵抗器１７、可変抵抗部１４（全
摺動部）及び抵抗器１９を介して流れる。従つ
て、可変抵抗部１４の全摺動部の範囲内でその摺
動端子を動かすことによりチユーナ４の制御電圧
端子VCに対応した制御電圧が供給され、これに
より所要の選局が可能となる。そして、この
UHFの受信時の制御電圧のスタート電圧は抵抗
器１９で設定され、つまりVHFのローチヤンネ
ル受信時と兼用され、エンド電圧は可変抵抗器１
７で設定される。 Also, when receiving VHF, switches 1 and 2 are switched to the contact b side, which causes the positive power supply +V _B1
is supplied to the tuner 4's power terminal UB. Positive power supply +V _B2 applied to fixed terminal b of switch 2
More current flows through the variable resistor 17, the variable resistance section 14 (all sliding sections), and the resistor 19. Therefore, by moving the sliding terminal within the range of all the sliding parts of the variable resistance section 14, a control voltage corresponding to the control voltage terminal VC of the tuner 4 is supplied, thereby making it possible to select the desired channel. . And this
The start voltage of the control voltage during UHF reception is set by resistor 19, which is also used when receiving VHF low channel, and the end voltage is set by variable resistor 1.
It is set at 7.

このようにして本実施例では第１図の回路に比
し、実質的にトランジスタを２個、抵抗器を４個
削減できる。また、選局用可変抵抗器１６′のス
イツチ部１５′に１接点型を用いたので、マイグ
レーシヨン対策としてカーボンを被せる必要がな
くなり、従つて、接点と摺動端子の間の接触抵抗
を小さくでき、これに生ずる電圧降下も小さくな
るので、特に減電圧使用時有利となる。また、可
変抵抗器２４が可変抵抗器１３と共に抵抗器１９
に比して大きな値となるように設定されているの
で、VHFのハイチヤンネルの受信時可変抵抗器
２７よりトランジスタ１１側に流れ込む電流が小
さい値に抑えられ、これにより無駄な電流が削減
され、消費電力が小さくて済む。 In this way, this embodiment can substantially reduce the number of transistors by two and the number of resistors by four, compared to the circuit shown in FIG. In addition, since a single contact type is used for the switch part 15' of the variable resistor 16' for tuning, there is no need to cover it with carbon as a migration countermeasure, and therefore the contact resistance between the contact and the sliding terminal is reduced. This is especially advantageous when using a reduced voltage because the resulting voltage drop is also small. Further, the variable resistor 24 is connected to the variable resistor 13 as well as the resistor 19.
Since the current flowing into the transistor 11 side from the variable resistor 27 is suppressed to a small value when receiving the VHF Haiti channel, the unnecessary current is reduced. Power consumption is small.

Ｈ考案の効果上述の如くこの考案によれば、従来回路より部
品点数を削減できるので、部品代の低減、マウン
ト工数の低減がなされ、全体として低廉化が図か
れ、またプリント基板上の占有率も低減できるの
で小型化が可能となる。H. Effects of the invention As mentioned above, this invention reduces the number of parts compared to conventional circuits, reducing parts costs and mounting man-hours, leading to lower costs overall, and reducing the occupancy on the printed circuit board. It is also possible to reduce the size of the device.

また、選局用可変抵抗器に１接点型のスイツチ
部を用いたので、こゝで降下する電圧が少なくな
り減電圧使用時有利となり、更にVHFのハイチ
ヤンネルの受信時無駄な電流が少ないので消費電
力が低くて済み、従つて特に低電圧駆動のセツト
に用いて有用である。 In addition, since a single-contact type switch part is used for the variable resistor for channel selection, the voltage drop is reduced, which is advantageous when using reduced voltage.Furthermore, there is less wasted current when receiving the VHF Haitian channel. It requires low power consumption and is therefore particularly useful in low voltage drive sets.

[Brief explanation of drawings]

第１図はこの考案の一実施例を示す回路構成
図、第２図は従来回路の一例を示す回路構成図で
ある。１，２はバンド切換スイツチ、３，１１はトラ
ンジスタ、４はチユーナ、１２，２５，２６はダ
イオード、１３，１７，２２，２４は可変抵抗
器、１４は可変抵抗部、１５′はスイツチ部、１
６′は選局用可変抵抗器、１９は抵抗器である。 FIG. 1 is a circuit diagram showing an embodiment of this invention, and FIG. 2 is a circuit diagram showing an example of a conventional circuit. 1 and 2 are band switching switches, 3 and 11 are transistors, 4 is a tuner, 12, 25, and 26 are diodes, 13, 17, 22, and 24 are variable resistors, 14 is a variable resistance section, 15' is a switch section, 1
6' is a variable resistor for channel selection, and 19 is a resistor.

Claims

[Claims for Utility Model Registration] A first fixed terminal of a first switch whose movable terminal is supplied with a first power source is connected to a first power terminal of the tuner via a main electrode path of a first transistor. and a second fixed terminal of the first switch connected to the second power terminal of the tuner via the switch section of a variable resistor for tuning consisting of a variable resistance section and a one-contact type switch section. is connected to a third power supply terminal of the tuner, a control electrode of the first transistor is connected to a reference power supply via a first diode, and a second switch is connected to a movable terminal of which a second power supply is supplied. A first fixed terminal of the variable resistance section is connected to an intermediate terminal of the variable resistance section via a first resistor and also connected to one end of the variable resistance section via a second diode and a second resistor, A second fixed terminal of the second switch is connected to one end of the variable resistance section via a third resistor, and the other end of the variable resistance section is connected to the reference power source via a fourth resistor. At the same time, the sliding terminal of the variable resistance section is connected to the control voltage terminal of the tuner, and the connection point between the first resistor and the intermediate terminal of the variable resistance section is connected to the fifth resistor and the second transistor. The control electrode of the second transistor is connected to the reference power source via a main electrode path, and the control electrode of the second transistor is connected to one end of the switch section and a second power terminal of the tuner, and the first transistor is connected to the reference power source via a third diode. A channel selection circuit comprising a diode connected to the cathode side of the first diode so that its polarity is opposite to that of the first diode.