JPS61287303A - Crystal oscillation circuit - Google Patents
Crystal oscillation circuitInfo
- Publication number
- JPS61287303A JPS61287303A JP12811785A JP12811785A JPS61287303A JP S61287303 A JPS61287303 A JP S61287303A JP 12811785 A JP12811785 A JP 12811785A JP 12811785 A JP12811785 A JP 12811785A JP S61287303 A JPS61287303 A JP S61287303A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- voltage
- trq1
- crystal
- oscillator
- 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.)
- Pending
Links
Landscapes
- Oscillators With Electromechanical Resonators (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、水晶発振回路に係り、特に低励振レベル領域
のインピーダンスが高くなった水晶振動子を用いても、
電源電圧の立上り時間の影響を受けず起動可能な発振回
路に関する。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a crystal oscillation circuit, and in particular, even if a crystal resonator with high impedance in a low excitation level region is used,
The present invention relates to an oscillation circuit that can be activated without being affected by the rise time of a power supply voltage.
従来の水晶発振回路は、「トランジスタ回路入門」（昭
和３８年３月２０日発行、柳沢健 著）の１０゜２．３
項に記載されている通りである。The conventional crystal oscillator circuit has a 10°2.3
As stated in section.
しかし、この回路は、Ｗ、４図に示す異常品のインピー
ダンス特性を持った水晶片が回路に組込まれた場合、起
動不良を起すことが多かった。これは、電源電圧の立上
り過渡期では、回路の増幅度が小さく、水晶片のインピ
ーダンスが高いからであり、電源電圧の立上りが遅い場
合に多く発生する。However, this circuit often causes startup failures when a crystal piece having the impedance characteristics of the abnormal product shown in FIG. 4 is incorporated into the circuit. This is because the amplification of the circuit is small and the impedance of the crystal piece is high during the transition period when the power supply voltage rises, and often occurs when the power supply voltage rises slowly.
本発明の目的は、水晶発振回路において、電源電圧の立
上り時間を全く考慮しなくても、確実に起動する発振回
路を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a crystal oscillation circuit that can be started up reliably without any consideration of the rise time of the power supply voltage.
従来の水晶発振回路では、電源電圧の立上り時間が遅い
場合、発振回路が起動する電源電圧が。In conventional crystal oscillator circuits, if the rise time of the power supply voltage is slow, the power supply voltage at which the oscillation circuit starts up is low.
電源電圧の立上り時間が速い場合に比較し高くなり、条
件しだいでは、規定の電源電圧で起動しない特性があっ
た。この原因は、水晶振動子の低励振レベル領域に、イ
ンピーダンスの高い部分があり、電源電圧の立上り時間
が遅いと、この領域を通過できないためである。本発明
は、トランジスタのベースバイアス電圧が、コレクタ電
圧より遅れて、しかも急激に立上る回路を設けたことを
特徴とするものである。The rise time of the power supply voltage is higher than when it is fast, and depending on the conditions, it has a characteristic that it will not start at the specified power supply voltage. The reason for this is that there is a high impedance portion in the low excitation level region of the crystal resonator, and if the power supply voltage has a slow rise time, it cannot pass through this region. The present invention is characterized in that a circuit is provided in which the base bias voltage of the transistor rises rapidly and later than the collector voltage.
以下、本発明の一実施例を第１図により説明する。 An embodiment of the present invention will be described below with reference to FIG.
第１図において、 Ｑ１＄Ｑ２はトランジスタ、Ｄｌは
ツェナーダイオード、ＣＩ、Ｃ２はコンデンサ、損〜Ｒ
４は抵抗、１は水晶振動子、２は電源端子、３は出力端
子、４はＧＮＤ端子である。In Figure 1, Q1$Q2 is a transistor, Dl is a Zener diode, CI, C2 is a capacitor, loss ~ R
4 is a resistor, 1 is a crystal resonator, 2 is a power supply terminal, 3 is an output terminal, and 4 is a GND terminal.
この回路は、第２図に示す公知の無調整発振回路にトラ
ンジスタＱ１．ツェナーダイオードＤ１、抵抗Ｒ４から
成る回路を付加したものである。This circuit consists of the well-known unregulated oscillation circuit shown in FIG. 2 and the transistor Q1. A circuit consisting of a Zener diode D1 and a resistor R4 is added.
第１図および第２図の発振回路の動作原理は、トランジ
スタＱ１のベース、コレクタ間に水晶発振子１とＣＩ、
Ｃ２より成るπ形回路が接続されているため、トランジ
スタＱ１のコレクタから出力された信号は、前述のπ形
回路により位相が１８σ変化ししかも、水晶の共振周波
数と同じ周波数成分のみが、トランジスタＱｌのベース
に帰還されるため、水晶振動子１の共振周波数で発振が
起る。しかし第２図の回路においては、電源端子２に印
加される電源の立上り時間が速い場合は、素子および回
路の容量のため、トランジスタＱ１のベースとコレクタ
電圧が同時に立上らず発振を起こすが、ＪｖＩＬ源の立
上り時間が遅い場合は、トランジスタＱ１のベースとコ
レクタ電圧が、はぼ同時に立上るため、水晶振動子のイ
ンピーダンスが高い場合や１回路の増幅度が小さい場合
には、起動しにくい欠点がある。The operating principle of the oscillation circuits shown in FIGS. 1 and 2 is that crystal oscillator 1 and CI are connected between the base and collector of transistor Q1.
Since the π-type circuit consisting of C2 is connected, the phase of the signal output from the collector of transistor Q1 changes by 18σ due to the aforementioned π-type circuit, and only the frequency component that is the same as the resonance frequency of the crystal is transmitted to the transistor Ql. Since it is fed back to the base of the crystal resonator 1, oscillation occurs at the resonant frequency of the crystal resonator 1. However, in the circuit shown in Figure 2, if the rise time of the power supply applied to power supply terminal 2 is fast, the base and collector voltages of transistor Q1 will not rise at the same time due to the capacitance of the element and circuit, causing oscillation. , if the rise time of the JvIL source is slow, the base and collector voltages of transistor Q1 rise almost simultaneously, making it difficult to start up if the impedance of the crystal oscillator is high or the amplification of one circuit is small. There are drawbacks.
第１図における本発明では、第３図に示すように、電源
電圧の立上りが遅くても、ツェナーダイオードＤ１のツ
ェナー電圧以上に電圧が上らないとトランジスタＱ２が
ＯＮせず、トランジスタＱ１にベースバイアス電圧が印
加されない。このことにより、電源電圧の立上り時間に
影響されず動作可能である。また、トランジスタＱ１の
ベースバイアス電圧は、ツェナーダイオードＤｌに電流
が流れると同時に、急激にかかるので、水晶振動子に対
して大きな励振エネルギーを与えることができ、発振回
路の起動性を良好九できる。In the present invention shown in FIG. 1, as shown in FIG. 3, even if the rise of the power supply voltage is slow, unless the voltage rises above the Zener voltage of the Zener diode D1, the transistor Q2 will not turn on, and the base of the transistor Q1 will be turned on. No bias voltage applied. This allows operation without being affected by the rise time of the power supply voltage. Further, since the base bias voltage of the transistor Q1 is applied rapidly at the same time as the current flows through the Zener diode Dl, a large excitation energy can be given to the crystal resonator, and the starting performance of the oscillation circuit can be improved.
この原理を第４図により説明する。第４図は水晶振動子
をドライブする励振レベルと共振点インピーダンス特性
を表したものである。水晶振動子は一般に、水晶片に汚
れや異物等が付着した場合、第４図の異常品のように、
励振レベルの低い部分でインピーダンスが高くなる不具
合が発生しゃすい。このような水晶振動子を発振回路に
組込んだ場合、励振レベルの大きな回路では問題なく起
動するが、電源電圧が低かったり、電源電圧の立上りが
遅かった場合、励振レベルが低くなるため起動不良にな
りやすい。本実施例によれば、低励振レベル領域を使用
しないため、水晶発振回路の起動特性を大幅に改善でき
る効果がある。This principle will be explained with reference to FIG. FIG. 4 shows the excitation level that drives the crystal resonator and the resonance point impedance characteristics. In general, when a crystal unit has dirt or foreign matter attached to it, as shown in the abnormal product shown in Figure 4,
Problems such as high impedance are likely to occur in areas where the excitation level is low. When such a crystal resonator is incorporated into an oscillation circuit, it will start up without any problem in a circuit with a large excitation level, but if the power supply voltage is low or the rise of the power supply voltage is slow, the excitation level will be low, causing startup failure. easy to become. According to this embodiment, since the low excitation level region is not used, there is an effect that the starting characteristics of the crystal oscillation circuit can be significantly improved.
本発明によれば、水晶発振回路の起動特性を良好にでき
るため、水晶振動子の特性バラツキや、回路のバラツキ
による起動不良を大幅に改善できると共に、電源電圧立
上り時間の影響をなくせる効果がある。According to the present invention, since the starting characteristics of the crystal oscillator circuit can be improved, it is possible to significantly improve starting defects caused by variations in the characteristics of the crystal resonator and variations in the circuit, and also to eliminate the effect of the power supply voltage rise time. be.
第１図は本発明の一実施例の回路図、第２図は従来の無
調整発振回路図、第３図は第２図の実施回路における各
部の電圧波形図、第４図は水晶の励振レベルとインピー
ダンス特性を示した線図である。Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a conventional unadjusted oscillation circuit diagram, Fig. 3 is a voltage waveform diagram of each part in the implementation circuit of Fig. 2, and Fig. 4 is a crystal excitation diagram. FIG. 3 is a diagram showing level and impedance characteristics.
Claims (1)
ンジスタのベースバイアス電圧が、コレクタ電圧より遅
れて、しかも急激に立上る回路を設けたことを特徴とす
る水晶発振回路。1. A crystal oscillation circuit using a transistor, characterized in that a circuit is provided in which the base bias voltage of the transistor rises rapidly and later than the collector voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12811785A JPS61287303A (en) | 1985-06-14 | 1985-06-14 | Crystal oscillation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12811785A JPS61287303A (en) | 1985-06-14 | 1985-06-14 | Crystal oscillation circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61287303A true JPS61287303A (en) | 1986-12-17 |
Family
ID=14976797
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12811785A Pending JPS61287303A (en) | 1985-06-14 | 1985-06-14 | Crystal oscillation circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61287303A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6133801A (en) * | 1996-04-23 | 2000-10-17 | Nec Corporation | Crystal oscillation circuit |
| WO2002007302A1 (en) * | 2000-07-17 | 2002-01-24 | Toyo Communication Equipment Co., Ltd. | Piezoelectric oscillator |
-
1985
- 1985-06-14 JP JP12811785A patent/JPS61287303A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6133801A (en) * | 1996-04-23 | 2000-10-17 | Nec Corporation | Crystal oscillation circuit |
| WO2002007302A1 (en) * | 2000-07-17 | 2002-01-24 | Toyo Communication Equipment Co., Ltd. | Piezoelectric oscillator |
| US6791424B2 (en) | 2000-07-17 | 2004-09-14 | Toyo Communication Equipment Co., Ltd. | Piezoelectric oscillator |
| JP2009239970A (en) * | 2000-07-17 | 2009-10-15 | Epson Toyocom Corp | Piezoelectric oscillator |
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