JP2008219438A - Capacitor switching circuit - Google Patents
Capacitor switching circuit Download PDFInfo
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- JP2008219438A JP2008219438A JP2007053576A JP2007053576A JP2008219438A JP 2008219438 A JP2008219438 A JP 2008219438A JP 2007053576 A JP2007053576 A JP 2007053576A JP 2007053576 A JP2007053576 A JP 2007053576A JP 2008219438 A JP2008219438 A JP 2008219438A
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- 239000003990 capacitor Substances 0.000 title claims abstract description 21
- 239000004065 semiconductor Substances 0.000 claims description 4
- 238000005513 bias potential Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000009499 grossing Methods 0.000 description 1
Abstract
Description
本発明は、全波受信機などの高周波回路に関し、さらに詳しくは、高周波同調回路の同調周波数を変更してバンド切り替えをする場合の同調用のコンデンサ切り替え回路に関する。 The present invention relates to a high-frequency circuit such as a full-wave receiver, and more particularly to a tuning capacitor switching circuit for switching a band by changing a tuning frequency of a high-frequency tuning circuit.
図１は従来の全波受信機などの高周波要部の回路図であり、同図においてＪ１はアンテナ端子、Ｌは整合トランス、Ｌ１は整合トランスの１次側、Ｌ２は整合トランスの２次側である。Ｌ２とＣ１、Ｃ２で同調回路を形成して、必要な周波数帯を選択する同調回路を形成する。
トランジスタＴＲ１１、ＴＲ１２は同調用コンデンサＣ１、Ｃ２をオン、オフすることにより同調周波数を切り替えるスイッチの役目をする。
FIG. 1 is a circuit diagram of a high-frequency main part of a conventional full-wave receiver or the like, in which J1 is an antenna terminal, L is a matching transformer, L1 is a primary side of the matching transformer, and L2 is a secondary side of the matching transformer. It is. A tuning circuit is formed by L2, C1, and C2, and a tuning circuit that selects a necessary frequency band is formed.
The transistors TR11 and TR12 serve as switches for switching the tuning frequency by turning on and off the tuning capacitors C1 and C2.
ＳＴＥＰ１にビット切り替え電圧を印加すると、この電圧がＲ１１を経てトランジスタＴＲ１１のベースに印加され、ＴＲ１１はオンとなり、同調コンデンサＣ１は、トランジスタＴＲ１１のコレクタを経て高周波的に接地されＬ２と同調回路を形成する。このＣ１の容量により同調周波数が決まる。 When a bit switching voltage is applied to STEP1, this voltage is applied to the base of transistor TR11 via R11, TR11 is turned on, and tuning capacitor C1 is grounded in high frequency via the collector of transistor TR11 to form a tuning circuit with L2. To do. The tuning frequency is determined by the capacitance of C1.
次に、ＳＴＥＰ１のビット切り替え電圧を０Ｖにして、ＳＴＥＰ２にビット切り替え電圧を印加すると、この電圧がＲ１２を経てトランジスタＴＲ１２のベースに印加され、ＴＲ１２はオンとなり、同調コンデンサＣ２は、トランジスタＴＲ１２のコレクタを経て高周波的に接地されＬ２と同調回路を形成する。このＣ２の容量により同調周波数が決まる。
このようにして、必要な同調回路を切り替えることができ、周波数帯を選択することができる。
Next, when the bit switching voltage of STEP1 is set to 0 V and the bit switching voltage is applied to STEP2, this voltage is applied to the base of the transistor TR12 via R12, TR12 is turned on, and the tuning capacitor C2 is connected to the collector of the transistor TR12. And is grounded at a high frequency to form a tuning circuit with L2. The tuning frequency is determined by the capacitance of C2.
In this way, a necessary tuning circuit can be switched and a frequency band can be selected.
図１に示す従来例では、トランジスタＴＲ１１がオンになる時、Ｃ１のコレクタ側の電位がバイアスＶｂ電位から０Ｖになり、トランジスタＴＲ１１がオフになる時には０Ｖからバイアス電位Ｖｂに変化するために切り替え時にノイズが発生して、受信機の音声出力よりノイズが出てしまう。 In the conventional example shown in FIG. 1, when the transistor TR11 is turned on, the potential on the collector side of C1 is changed from the bias Vb potential to 0V, and when the transistor TR11 is turned off, the potential changes from 0V to the bias potential Vb. Noise is generated and noise is generated from the audio output of the receiver.
これを解決する方法としてスイッチ波形をなだらかにする目的でＴＲ１１のベースにコンデンサＣ１１を付ける方法があるがビット切り替え速度が遅くなる欠点がある。 As a method of solving this, there is a method of attaching a capacitor C11 to the base of TR11 for the purpose of smoothing the switch waveform.
本発明は、上述の点に鑑みて為されたものであって、ＴＲ１１のベースにコンデンサを付けることなく、切り替えスイッチのイイズ発生を無くして、受信機の音声出力からノイズを出さない回路を提供することを目的とする。 The present invention has been made in view of the above points, and provides a circuit that does not generate noise from the audio output of the receiver without adding a capacitor to the base of the TR 11 and eliminating the noise generation of the changeover switch. The purpose is to do.
本発明では、上述の目的を達成するために次のように構成している。 The present invention is configured as follows in order to achieve the above-described object.
すなわち、本発明は、高周波同調回路において、同調用コンデンサを切り替える半導体にフォトトランジスタを使用して、このフォトトランジスタの電源に、プラス電源とマイナス電源を使用している。 That is, according to the present invention, a phototransistor is used as a semiconductor for switching a tuning capacitor in a high frequency tuning circuit, and a positive power source and a negative power source are used as a power source for the phototransistor.
また、本発明は、高周波同調回路において、同調用コンデンサを切り替える半導体にトランジスタを使用して、このトランジスタの電源に、プラス電源とマイナス電源を使用し、前記トランジスタを駆動するのにフォトトランジスタを使用して、このフォトトランジスタの電源に、プラス電源とマイナス電源を使用している。 Further, the present invention uses a transistor as a semiconductor for switching a tuning capacitor in a high-frequency tuning circuit, uses a positive power source and a negative power source as a power source of the transistor, and uses a phototransistor to drive the transistor A positive power source and a negative power source are used as the power source of the phototransistor.
本発明によれば、高周波同調回路において、同調用コンデンサを切り替えても、切り替えのノイズが発生せず、受信機の音声出力よりノイズが出ることはなくなる。 According to the present invention, even when the tuning capacitor is switched in the high frequency tuning circuit, switching noise does not occur, and noise does not occur from the audio output of the receiver.
以下、図面によって本発明の実施例について、詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
図２は、本発明の高周波要部の回路図であり、図１の従来例に対応する部分には、同一の参照符号を付す。 FIG. 2 is a circuit diagram of the high-frequency main part of the present invention, and parts corresponding to the conventional example of FIG.
同図においてＪ１はアンテナ端子、Ｌは整合トランス、Ｌ１は整合トランスの１次側、Ｌ２は整合トランスの２次側である。Ｌ２とＣ１、Ｃ２で同調回路を形成して、必要な周波数帯を選択する同調回路を形成する。フォトトランジスタＵ２１,Ｕ２２は同調用コンデンサＣ１を、フォトトランジスタＵ２３,Ｕ２４は同調用コンデンサＣ２をオン、オフすることにより同調周波数を選択するスイッチの役目をする。Ｕ２１,Ｕ２２およびＵ２３,Ｕ２４には図の様にプラス電源とマイナス電源を印加して、この電源の中点電位が同調コンデンサＣ１、Ｃ２のバイアス電位とする。 In the figure, J1 is an antenna terminal, L is a matching transformer, L1 is a primary side of the matching transformer, and L2 is a secondary side of the matching transformer. A tuning circuit is formed by L2, C1, and C2, and a tuning circuit that selects a necessary frequency band is formed. The phototransistors U21 and U22 serve as a switch for selecting a tuning frequency by turning on and off the tuning capacitor C1, and the phototransistors U23 and U24 by turning on and off the tuning capacitor C2. A positive power source and a negative power source are applied to U21, U22 and U23, U24 as shown in the figure, and the midpoint potential of this power source becomes the bias potential of the tuning capacitors C1, C2.
ＳＴＥＰ１にビット切り替え電圧印加すると、Ｒ２５を経てフォトトランジスタＵ２１,Ｕ２２に印加されＵ２１,Ｕ２２がオンとなり、プラス電源からマイナス電源へ抵抗器Ｒ２２,Ｒ２１を経て電流が流れるが、Ｒ２１＝Ｒ２２のとき、Ｃ１の電位は変わらないので切り替えのノイズが発生することはなく、受信機の音声出力からのノイズが出ることはない。
ビット切り替え電圧がＣＭＯＳあるいはＴＴＬレベルの場合に対応するため駆動する回路をフォトトランジスタとした。
When a bit switching voltage is applied to STEP 1, it is applied to phototransistors U 21 and U 22 via R 25, U 21 and U 22 are turned on, and a current flows from the positive power source to the negative power source through resistors R 22 and R 21, but when R 21 = R 22, Since the potential of C1 does not change, switching noise does not occur, and noise from the audio output of the receiver does not appear.
The circuit to be driven is a phototransistor to cope with the case where the bit switching voltage is at the CMOS or TTL level.
次に、ＳＴＥＰ１のビット切り替え電圧を０として、ＳＴＥＰ２にビット切り替え電圧印加すると、Ｒ２６を経てフォトトランジスタＵ２３,Ｕ２４に印加されＵ２３,Ｕ２４がオンとなり、プラス電源からマイナス電源へ抵抗器Ｒ２４,Ｒ２３を経て電流が流れるが、Ｒ２４＝Ｒ２３のとき、Ｃ２の電位は変わらないので切り替えのノイズが発生することはなく、受信機の音声出力からのノイズが出ることはない。
ビット切り替え電圧がＣＭＯＳあるいはＴＴＬレベルの場合に対応するため駆動する回路をフォトトランジスタとした。
Next, when the bit switching voltage of STEP1 is set to 0 and the bit switching voltage is applied to STEP2, it is applied to the phototransistors U23 and U24 via R26 and U23 and U24 are turned on, and the resistors R24 and R23 are switched from the positive power source to the negative power source. After that, a current flows, but when R24 = R23, the potential of C2 does not change, so switching noise does not occur, and noise from the audio output of the receiver does not appear.
The circuit to be driven is a phototransistor to cope with the case where the bit switching voltage is at the CMOS or TTL level.
図３は他の実施例である。この例では、同調用コンデンサＣ１およびＣ２を切り替えるのにトランジスタＴＲ３１,ＴＲ３２およびＴＲ３３、ＴＲ３４を使用している。また、これらのトランジスタの電源に、プラス電源とマイナス電源を使用している。これらのトランジスタをオン、オフとするための駆動にフォトトランジスタを使用して、ビット切り替え電圧がＣＭＯＳあるいはＴＴＬレベルの場合に対応している。 FIG. 3 shows another embodiment. In this example, transistors TR31, TR32 and TR33, TR34 are used to switch the tuning capacitors C1 and C2. Further, a positive power source and a negative power source are used as the power source of these transistors. A phototransistor is used for driving to turn these transistors on and off, and the bit switching voltage corresponds to the CMOS or TTL level.
次に実際の動作を説明する。ＳＴＥＰ１にビット切り替え電圧を印加すると、Ｒ３５を経てフォトトランジスタＵ３１,Ｕ３２に印加されＵ３１,Ｕ３２がオンとなると、ＴＲ３１、ＴＲ３２はオンとなり、プラス電源からマイナス電源へ抵抗器Ｒ３２,Ｒ３１を経て電流が流れるが、Ｒ３１＝Ｒ３２のとき、Ｃ１の電位は変わらないので切り替えのノイズが発生することはなく、受信機の音声出力からのノイズが出ることはない。 Next, the actual operation will be described. When a bit switching voltage is applied to STEP1, it is applied to the phototransistors U31 and U32 via R35 and when U31 and U32 are turned on, TR31 and TR32 are turned on, and the current flows from the positive power source to the negative power source through resistors R32 and R31. However, when R31 = R32, the potential of C1 does not change, so switching noise does not occur, and noise from the audio output of the receiver does not appear.
次に、ＳＴＥＰ１のビット切り替え電圧を０Ｖとして、ＳＴＥＰ２にビット切り替え電圧印加すると、Ｒ３６を経てフォトトランジスタＵ３３,Ｕ３４に印加されＵ３３,Ｕ３４がオンとなり、ＴＲ３３、ＴＲ３４はオンとなり、プラス電源からマイナス電源へ抵抗器Ｒ３３,Ｒ３４を経て電流が流れるが、Ｒ３３＝Ｒ３４のとき、Ｃ２の電位は変わらないので切り替えのノイズが発生することはなく、受信機の音声出力からのノイズが出ることはない。 Next, when the bit switching voltage of STEP1 is set to 0V and the bit switching voltage is applied to STEP2, it is applied to the phototransistors U33 and U34 via R36, U33 and U34 are turned on, TR33 and TR34 are turned on, and the positive power supply is changed to the negative power supply. Current flows through the resistors R33 and R34, but when R33 = R34, the potential of C2 does not change, so switching noise does not occur and noise from the audio output of the receiver does not appear.
本発明は、高周波同調回路において、同調用コンデンサを切り替えても、切り替えノイズが発生することがなく、受信機の音声出力よりノイズが出ることがない切り替え回路として利用可能である。 INDUSTRIAL APPLICABILITY The present invention can be used as a switching circuit in a high-frequency tuning circuit in which switching noise does not occur even when the tuning capacitor is switched, and noise is not generated from the audio output of the receiver.
Ｊ１…アンテナ端子、 Ｃ１，Ｃ２…同調用コンデンサ、 Ｌ…整合トランス、
Ｌ１…整合トランス１次側、 Ｌ２…整合トランス２次側、
Ｖｂ…バイアス電圧、 −Ｖ…マイナス電源、 ＋Ｖ…プラス電源、
ＳＴＥＰ１，ＳＴＥＰ２…切り替え電圧、
ＴＲ１１，ＴＲ１２，ＴＲ３１，ＴＲ３２，ＴＲ３３，ＴＲ３４…トランジスタ、
Ｕ２１，Ｕ２２，Ｕ２３，Ｕ２４，Ｕ３１，Ｕ３２，Ｕ３３，Ｕ３４…フォトトランジスタ
J1 ... antenna terminal, C1, C2 ... tuning capacitor, L ... matching transformer,
L1 ... matching transformer primary side, L2 ... matching transformer secondary side,
Vb: Bias voltage, -V: Negative power supply, + V: Positive power supply,
STEP1, STEP2 ... Switching voltage,
TR11, TR12, TR31, TR32, TR33, TR34 ... transistors,
U21, U22, U23, U24, U31, U32, U33, U34 ... Phototransistor
Claims (2)
In a high-frequency tuning circuit, a transistor is used as a semiconductor for switching a tuning capacitor, a positive power source and a negative power source are used as a power source of the transistor, and a phototransistor is used to drive the transistor. Capacitor switching circuit for tuning, characterized in that a positive power source and a negative power source are used as the power source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007053576A JP4693801B2 (en) | 2007-03-05 | 2007-03-05 | Capacitor switching circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007053576A JP4693801B2 (en) | 2007-03-05 | 2007-03-05 | Capacitor switching circuit |
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| Publication Number | Publication Date |
|---|---|
| JP2008219438A true JP2008219438A (en) | 2008-09-18 |
| JP4693801B2 JP4693801B2 (en) | 2011-06-01 |
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| JP2007053576A Expired - Fee Related JP4693801B2 (en) | 2007-03-05 | 2007-03-05 | Capacitor switching circuit |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS575428A (en) * | 1980-05-09 | 1982-01-12 | Motorola Inc | Analog-to-digital converter |
| JPS58196714A (en) * | 1982-05-13 | 1983-11-16 | Oki Electric Ind Co Ltd | Tuning circuit |
| JP2002094381A (en) * | 2000-09-14 | 2002-03-29 | Sharp Corp | Digital to analog converter circuit and image display device using the same |
| JP2004222249A (en) * | 2003-01-09 | 2004-08-05 | Phonak Communications Ag | Method of tuning lc resonator, integrated circuit for tuning lc resonator and electrical apparatus having lc resonator |
| JP2006295483A (en) * | 2005-04-08 | 2006-10-26 | Alps Electric Co Ltd | Receiving device |
| JP2006324773A (en) * | 2005-05-17 | 2006-11-30 | Alps Electric Co Ltd | Receiving device |
-
2007
- 2007-03-05 JP JP2007053576A patent/JP4693801B2/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS575428A (en) * | 1980-05-09 | 1982-01-12 | Motorola Inc | Analog-to-digital converter |
| JPS58196714A (en) * | 1982-05-13 | 1983-11-16 | Oki Electric Ind Co Ltd | Tuning circuit |
| JP2002094381A (en) * | 2000-09-14 | 2002-03-29 | Sharp Corp | Digital to analog converter circuit and image display device using the same |
| JP2004222249A (en) * | 2003-01-09 | 2004-08-05 | Phonak Communications Ag | Method of tuning lc resonator, integrated circuit for tuning lc resonator and electrical apparatus having lc resonator |
| JP2006295483A (en) * | 2005-04-08 | 2006-10-26 | Alps Electric Co Ltd | Receiving device |
| JP2006324773A (en) * | 2005-05-17 | 2006-11-30 | Alps Electric Co Ltd | Receiving device |
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| JP4693801B2 (en) | 2011-06-01 |
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