JPH061857B2 - Oscillator circuit - Google Patents
Oscillator circuitInfo
- Publication number
- JPH061857B2 JPH061857B2 JP33196288A JP33196288A JPH061857B2 JP H061857 B2 JPH061857 B2 JP H061857B2 JP 33196288 A JP33196288 A JP 33196288A JP 33196288 A JP33196288 A JP 33196288A JP H061857 B2 JPH061857 B2 JP H061857B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- resistor
- oscillator
- capacitor
- differential amplifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Oscillators With Electromechanical Resonators (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は発振回路に係り、特にＩＣ（集積回路）に内蔵
する発振回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillator circuit, and more particularly to an oscillator circuit incorporated in an IC (integrated circuit).
従来の技術 ＩＣに内蔵する発振回路としては、第４図及び第５図に
示すように２端子型の回路と１端子型の回路とがあっ
た。第４図に示す２端子型の回路はＩＣ内に設けられた
インバータ３の入出力を外付け用端子Ｔ１，Ｔ３として
外付け用端子Ｔ２，Ｔ３間に抵抗Ｒ３及び水晶振動子Ｚ
を並列に接続すると共に夫々の外付け用端子Ｔ２，Ｔ３
と接地とはコンデンサＣ２，Ｃ３を介して接続するいわ
ゆるコルピッツ型の構成が主流であった。2. Description of the Related Art Oscillation circuits built in an IC include a two-terminal type circuit and a one-terminal type circuit as shown in FIGS. The fourth two-terminal circuit shown in FIG resistor R 3 and a crystal oscillating between for external terminal T 2, T 3 input and output of the inverter 3 provided in the IC as external terminals T 1, T 3 Child Z
Are connected in parallel and the external terminals T 2 and T 3 are connected.
The mainstream was a so-called Colpitts type configuration in which the capacitor and the ground are connected via capacitors C 2 and C 3 .
また、第５図の１端子型の回路は増幅回路４の入力端子
を外付け用端子Ｔ４として、この外付け用端子Ｔ４と接
地間に水晶振動子Ｚを接続する構成であった。Moreover, first terminal-type circuit of Figure 5 is an input terminal of the amplifier circuit 4 as external terminals T 4, and a configuration for connecting the crystal oscillator Z between ground and the external terminal T 4.
発明が解決しようとする課題 しかるに、第４図に示す２端子型の発振回路は外付けす
る部品が多く、また、外付け用端子も２つ必要となり、
ＩＣの機能の複号化の上で好ましくない。また、第５図
に示す１端子型の発振回路ではスプリアス発振を防ぐた
め、増幅回路４の出力側に比較的大きい容量のコンデン
サＣ４，Ｃ５を設ける必要があったため、これをＩＣ内
に内蔵しようとするとＩＣ化が困難である等の問題点が
あった。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, the two-terminal type oscillation circuit shown in FIG. 4 has many external parts, and two external terminals are required.
It is not preferable in terms of decoding the IC function. Further, in the one-terminal type oscillating circuit shown in FIG. 5, in order to prevent spurious oscillation, it was necessary to provide capacitors C 4 and C 5 having a relatively large capacitance on the output side of the amplifying circuit 4. However, there is a problem that it is difficult to form an IC when it is built in.
本発明は上記の点に鑑みてなされたもので、ＩＣ化が容
易となる発振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 an object of the present invention is to provide an oscillation circuit that can be easily integrated into an IC.
課題を解決するための手段 本発明は第１の抵抗がコンデンサに対向し、かつ、第２
の抵抗が第１の抵抗に接続されると共に振動子に対向す
る構成のブリッジ回路と、 第１及び第２の抵抗の接続点にその出力端が接続され、
かつ、第２の抵抗とコンデンサの接続点に第１の入力端
子が接続されると共に第１の抵抗と振動子の接続点に第
２の入力端子が接続された差動増幅回路とよりなる。Means for Solving the Problems According to the present invention, a first resistor faces a capacitor, and a second resistor is provided.
The resistor is connected to the first resistor and the output terminal is connected to the connection point of the bridge circuit and the first and second resistors that are opposed to the vibrator.
The differential amplifier circuit has a first input terminal connected to the connection point of the second resistor and the capacitor and a second input terminal connected to the connection point of the first resistor and the oscillator.
作用 振動子を差動増幅回路と接地との間に設けることができ
る。また、振動子の共振点と反共振点以外の周波数領域
では振動子は容量性を示すため、付加コンデンサの容量
を振動子の電極間容量より十分に小さくすることにより
正帰還ループ側に設けられた振動子のインピーダンスに
比し、負帰還ループ側に設けられた付加コンデンサのイ
ンピーダンスを大きくできるため回路の正帰還ループよ
り負帰還ループのゲインが大きくなり、異常発振を起こ
すことがなく安定した発振を行なえる。このため、付加
コンデンサの容量を小さく、また、振動子を差動増幅回
路と接地間に設ける構成で安定した発振が可能となる。The oscillator can be provided between the differential amplifier circuit and the ground. In addition, since the oscillator exhibits capacitive properties in the frequency range other than the resonance point and anti-resonance point of the oscillator, it is provided on the positive feedback loop side by making the capacitance of the additional capacitor sufficiently smaller than the capacitance between the electrodes of the oscillator. Since the impedance of the additional capacitor provided on the negative feedback loop side can be made larger than the impedance of the oscillator, the gain of the negative feedback loop becomes larger than that of the positive feedback loop of the circuit, and stable oscillation without abnormal oscillation occurs. Can be done. Therefore, the capacity of the additional capacitor is small, and stable oscillation is possible with the configuration in which the vibrator is provided between the differential amplifier circuit and the ground.
実施例 第１図は本発明の原理ブロツク図を示す。１は差動増幅
回路、Ｚは水晶振動子を示す。Embodiment FIG. 1 shows a block diagram of the principle of the present invention. Reference numeral 1 represents a differential amplifier circuit, and Z represents a crystal oscillator.
ブリッジ回路は抵抗Ｒ１，Ｒ２，水晶振動子Ｚ，コンデ
ンサＣａよりなり、抵抗Ｒ１，Ｒ２を直列に接続し、水
晶振動子ＺとコンデンサＣａとを直列に接続してブリッ
ジを構成している。ブリッジ回路の抵抗Ｒ１と抵抗Ｒ２
との接続点は差動増幅回路１の出力端子に接続され、抵
抗Ｒ２とコンデンサＣａとの接続点は差動増幅回路１の
反転入力端子に接続され、抵抗Ｒ１と水晶振動子Ｚとの
接続点は差動増幅回路１の非反転入力端子に接続され
る。また、水晶振動子ＺとコンデンサＣａとの接続点は
接地される。The bridge circuit comprises resistors R 1 and R 2 , a crystal oscillator Z, and a capacitor Ca. The resistors R 1 and R 2 are connected in series, and the crystal oscillator Z and the capacitor Ca are connected in series to form a bridge. ing. Resistance R 1 and resistance R 2 of the bridge circuit
Is connected to the output terminal of the differential amplifier circuit 1, the connection point of the resistor R 2 and the capacitor Ca is connected to the inverting input terminal of the differential amplifier circuit 1, and the resistor R 1 and the crystal oscillator Z are connected. The connection point of is connected to the non-inverting input terminal of the differential amplifier circuit 1. The connection point between the crystal unit Z and the capacitor Ca is grounded.
したがって、抵抗Ｒ１、機械振動子Ｚとにより正帰還ル
ープが構成され、抵抗Ｒ２付加コンデンサＣａにより負
帰還ループが構成され、発振が行なわれる構成である。Therefore, the resistor R 1 and the mechanical oscillator Z form a positive feedback loop, and the resistor R 2 additional capacitor Ca forms a negative feedback loop to oscillate.
第２図は本発明の実施例の回路図を示す。差動増幅回路
１はＮＰＮトランジスタＴｒ１，Ｔｒ２，Ｔｒ３，抵抗
Ｒ３〜Ｒ６，ダイオードＤ，定電流源Ｃ．Ｃ１，Ｃ．Ｃ
２とよりなり、ダイオードＤと定電流源Ｃ．Ｃ２との接
続点が出力端子２に、トランジスタＴｒ１のベースが非
反転入力端子に、また、トランジスタＴｒ２のベースが
反転入力端子となる。抵抗Ｒ１，Ｒ２は位相シフト用の
抵抗とバイアス用の抵抗とを共用する構成とされてい
る。FIG. 2 shows a circuit diagram of an embodiment of the present invention. The differential amplifier circuit 1 includes NPN transistors T r1 , T r2 , T r3 , resistors R 3 to R 6 , a diode D, a constant current source C. C 1 , C.I. C
2 , a diode D and a constant current source C. Connection point of the C 2 to the output terminal 2, the base of the transistor T r1 is the non-inverting input terminal, and the base of the transistor T r2 is the inverting input terminal. The resistors R 1 and R 2 are configured to share a phase shift resistor and a bias resistor.
また、差動増幅回路１の同相利得は略０とし、逆相利得
は１０程度に確保する。Further, the in-phase gain of the differential amplifier circuit 1 is set to about 0, and the anti-phase gain is set to about 10.
機械振動子Ｚの等価的回路は第３図に示すような構成
で、インダクタンスＬ０，容量Ｃ０，抵抗ｒ０よりなる
直列回路に電極間容量Ｃ１を並列に接続してなる。機械
振動子Ｚのリアクタンス特性は共振周波数ｆｓと反共振
周波数ｆｐとの間の領域で誘導性を示し、それ以外の領
域では容量性を示す。また、電極間容量Ｃ１は５００
ＰＦ程度あり、負帰還ループ側に設けられた付加コンデ
ンサＣａは数十ＰＦ程度と小さい容量に設定され、Ｃ１
≫Ｃａである。このため機械振動子Ｚの共振点と反共振
点との間の周波数領域では非反転端子と接地間のインピ
ーダンスは反転端子と接地間のインピーダンスより十分
に小さくなるため、正帰還ループより負帰還ループ側の
ゲインが大きくなる。このため、異常発振（スプリアス
発振）が生じにくくなる。The equivalent circuit of the mechanical oscillator Z has a configuration as shown in FIG. 3, and is formed by connecting an interelectrode capacitance C 1 in parallel to a series circuit including an inductance L 0 , a capacitance C 0 , and a resistance r 0 . The reactance characteristic of the mechanical oscillator Z is inductive in a region between the resonance frequency fs and the anti-resonance frequency fp, and is capacitive in other regions. The interelectrode capacitance C 1 is 500
There about PF, additional capacitor Ca provided in the negative feedback loop side is set to several tens PF about a small capacitance, C 1
>> Ca. Therefore, in the frequency region between the resonance point and the anti-resonance point of the mechanical oscillator Z, the impedance between the non-inverting terminal and the ground is sufficiently smaller than the impedance between the inverting terminal and the ground. Side gain becomes large. Therefore, abnormal oscillation (spurious oscillation) is less likely to occur.
また、付加コンデンサＣａは機械振動子Ｚそのものの発
振周波数ｆ０近傍で反転入力端子接地間電圧ｅ２を若干
減衰させる。このため、差動増幅回路１に実効的に差動
入力を与える。このため、位相差が生じ、機械振動子Ｚ
自身の並列共振周波数（反共振周波）ｆｐより若干ずれ
た周波数で発振を行なうことになる。このずれはごく微
小なもので発振の安定度は高い。Further, the additional capacitor Ca slightly attenuates the inverting input terminal ground voltage e 2 in the vicinity of the oscillation frequency f 0 of the mechanical oscillator Z itself. Therefore, the differential input is effectively applied to the differential amplifier circuit 1. For this reason, a phase difference occurs and the mechanical oscillator Z
Oscillation is performed at a frequency slightly deviated from its own parallel resonance frequency (anti-resonance frequency) fp. This deviation is very small and the oscillation stability is high.
なお、差動増幅回路１は第２図に示すような構成のもの
に限ることはなく、同相利得がほぼ０，逆相利得が１０
程度得られるものであればよい。The differential amplifier circuit 1 is not limited to the configuration shown in FIG. 2, and the in-phase gain is almost 0 and the anti-phase gain is 10.
Anything that can be obtained is acceptable.
発明の効果 上述の如く、本発明によれば、振動子を差動増幅回路の
入力端子と接地間に設ければよく、また、付加コンデン
サの容量も小容量のものでよいため、ＩＣ化する際に付
加コンデンサを内蔵でき、また、振動子を外付けする際
の専有端子も１つで済むことからＩＣの機能複合化に際
し有利となる等の特長を有する。EFFECTS OF THE INVENTION As described above, according to the present invention, the oscillator may be provided between the input terminal of the differential amplifier circuit and the ground, and the capacitance of the additional capacitor may be small. In this case, an additional capacitor can be built in, and since only one dedicated terminal is required for externally attaching the vibrator, it is advantageous in compounding IC functions.
第１図は本発明の原理ブロック図、第２図は本発明の一
実施例の回路図、第３図は水晶振動子の等価回路図、第
４図は従来のブロック図、第５図は従来の他の一例のブ
ロック図を示す。 １…差動増幅回路、Ｒ１，Ｒ２…抵抗、Ｃａ…コンデン
サ、Ｚ…水晶振動子。FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a circuit diagram of an embodiment of the present invention, FIG. 3 is an equivalent circuit diagram of a crystal unit, FIG. 4 is a conventional block diagram, and FIG. The block diagram of another conventional example is shown. 1 ... Differential amplifier circuit, R 1 , R 2 ... Resistor, Ca ... Capacitor, Z ... Crystal oscillator.
Claims (1)
第２の抵抗が該第１の抵抗に接続されると共に振動子に
対向する構成のブリッジ回路と、 該第１及び第２の抵抗の接続点にその出力端子が接続さ
れ、かつ、該第２の抵抗と該コンデンサの接続点に第１
の入力端子が接続されると共に該第１の抵抗と該振動子
の接続点に第２の入力端子が接続された差動増幅回路と
よりなることを特徴とする発振回路。1. A first resistor faces a capacitor, and
A bridge circuit having a structure in which a second resistor is connected to the first resistor and facing the vibrator, and an output terminal thereof is connected to a connection point of the first and second resistors, and the second circuit No. 1 at the connection point between the resistor and the capacitor
And an input terminal connected to the first resistor and a differential amplifier circuit having a second input terminal connected to a connection point of the vibrator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33196288A JPH061857B2 (en) | 1988-12-29 | 1988-12-29 | Oscillator circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33196288A JPH061857B2 (en) | 1988-12-29 | 1988-12-29 | Oscillator circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02179105A JPH02179105A (en) | 1990-07-12 |
| JPH061857B2 true JPH061857B2 (en) | 1994-01-05 |
Family
ID=18249591
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33196288A Expired - Lifetime JPH061857B2 (en) | 1988-12-29 | 1988-12-29 | Oscillator circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH061857B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9034961B2 (en) | 2011-10-18 | 2015-05-19 | Bridgestone Corporation | Rubber composition and tire using the same |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3104652B2 (en) * | 1997-09-05 | 2000-10-30 | 日本電気株式会社 | Oscillation circuit |
| WO2016031963A1 (en) * | 2014-08-29 | 2016-03-03 | 株式会社村田製作所 | Oscillator circuit |
-
1988
- 1988-12-29 JP JP33196288A patent/JPH061857B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9034961B2 (en) | 2011-10-18 | 2015-05-19 | Bridgestone Corporation | Rubber composition and tire using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02179105A (en) | 1990-07-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| EXPY | Cancellation because of completion of term |