JP2007318398A - Crystal oscillator circuit - Google Patents

Crystal oscillator circuit Download PDF

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JP2007318398A
JP2007318398A JP2006145050A JP2006145050A JP2007318398A JP 2007318398 A JP2007318398 A JP 2007318398A JP 2006145050 A JP2006145050 A JP 2006145050A JP 2006145050 A JP2006145050 A JP 2006145050A JP 2007318398 A JP2007318398 A JP 2007318398A
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circuit
input
crystal
monopulse
input terminal
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Masashi Takamatsu
昌史 高松
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Seiko NPC Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystal oscillator circuit which is simple in circuit configuration and can shorten a period of time required for establishing a steady oscillation state after input of an activation signal. <P>SOLUTION: The crystal oscillator circuit 1 includes an external crystal vibrator 2, a feedback resistance 3, and an inverter 6 which amplifies the oscillation amplitude of the crystal vibrator 2, and is provided with a switching element, comprising a transistor 9 turning on for a predetermined time with an actuation signal to lower the potential at an input terminal A, at the input terminal A. The transistor 9 is controlled to turn on while a monopulse generating circuit 10 generating a monopulse on input of the activation signal outputs a monopulse signal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、水晶発振回路に関する。   The present invention relates to a crystal oscillation circuit.

水晶発振回路は、水晶振動子の発振振幅を増幅させる増幅回路（インバータ）を備え、その入力端は、発振停止時には電源電圧に固定され、起動信号が与えられると、入力端は電源電圧から切り離されて、徐々に発振が開始される。水晶発振回路は入力信号を必要とせず、発振条件さえ満たしていれば、徐々に発振するのであるが、入力端の電位が定常状態の電位レベルにまで下がるのに時間がかかり、安定動作に達するまでには長時間を要するのが一般的である。   The crystal oscillation circuit includes an amplifier circuit (inverter) that amplifies the oscillation amplitude of the crystal resonator, and its input terminal is fixed to the power supply voltage when oscillation is stopped, and the input terminal is disconnected from the power supply voltage when a start signal is given. The oscillation starts gradually. A crystal oscillation circuit does not require an input signal and oscillates gradually as long as the oscillation conditions are met. However, it takes time for the potential at the input terminal to drop to a steady-state potential level, resulting in stable operation. It usually takes a long time to complete.

従来においても、電源投入後の発振開始から安定した発振までの起動時間の短縮を図ったものとして、水晶発振子の両端に、互いに位相の異なるクロック信号を一定時間与えて、水晶振動子の励振を促進することが提案されている。（特許文献１）
特開平１１−２８４４３８号公報 In the past, it was assumed that the startup time from the start of oscillation after power-on to the stable oscillation was shortened, and clock signals with different phases were given to both ends of the crystal oscillator for a certain period of time to excite the crystal resonator. It has been proposed to promote. (Patent Document 1)
Japanese Patent Laid-Open No. 11-284438

ところが、上述した改良提案では、発振回路が待機状態にあるときでもクロック信号を生成する回路やクロック信号をカウントするカウンタなどを必要とするので、回路構成が複雑になるという不都合がある。本発明は、この不都合を解消した水晶発振回路を提供することを目的とする。   However, the above-described improvement proposal requires a circuit that generates a clock signal and a counter that counts the clock signal even when the oscillation circuit is in a standby state. An object of the present invention is to provide a crystal oscillation circuit that eliminates this inconvenience.

本発明は、起動信号入力前には電源電圧と同レベルにある入力端の電位を、起動信号の入力時に、一時的に接地方向に下げて、定常状態になるのを促進するもので、具体的には、本発明の請求項１に係る水晶発振回路は、例えば水晶振動子を外付けし、この水晶振動子の発振振幅を増幅させる増幅回路を備えた水晶発信回路において、この水晶発振回路の入力端に、起動信号によって所定時間オン動作して前記入力端の電位を下げるスイッチング素子を設けたものである。   The present invention promotes the steady state by lowering the potential of the input terminal, which is at the same level as the power supply voltage before inputting the activation signal, temporarily in the ground direction when the activation signal is input. Specifically, a crystal oscillation circuit according to claim 1 of the present invention is a crystal oscillation circuit including an amplification circuit that externally attaches a crystal resonator and amplifies the oscillation amplitude of the crystal resonator. Is provided with a switching element that is turned on for a predetermined time by an activation signal to lower the potential of the input terminal.

また、本発明の請求項２に係る水晶発振回路は、上述のスイッチング素子を、水晶発振回路の入力端と接地間に挿入されたトランジスタで構成し、このトランジスタは、起動信号が入力するとモノパルスを発生するモノパルス発生回路によってオンオフ制御されるよう構成したものである。   In the crystal oscillation circuit according to claim 2 of the present invention, the switching element described above is configured by a transistor inserted between the input terminal of the crystal oscillation circuit and the ground, and this transistor outputs a monopulse when an activation signal is input. It is configured to be on / off controlled by a generated monopulse generation circuit.

本発明に係る水晶発振回路によれば、起動信号の入力時に水晶発振回路の入力端の電位を一時的に下げることにより、起動信号が入力して発振を開始してから発振動作が安定する定常状態になるまでの時間を短縮することができるという効果を奏する。   According to the crystal oscillation circuit according to the present invention, when the activation signal is input, the potential at the input terminal of the crystal oscillation circuit is temporarily lowered, so that the oscillation operation is stabilized after the activation signal is input and oscillation is started. There is an effect that the time until the state is reached can be shortened.

以下、本発明の好適な実施形態を、図１に示す概略的な回路図に基づいて説明する。水晶発振回路１は、外付けした水晶発振子２と、帰還抵抗３と、この帰還抵抗３と直列に挿入し、水晶発振回路１の待機時にはオフ状態で、起動信号が入力するとオン状態になるトランスファゲート回路４と、前記帰還抵抗３と前記トランスファゲート回路４の接続点と電源との間に挿入し、水晶発振回路１の待機時にはオン状態で、起動信号がゲートに入力するとオフ状態になるＭＯＳトランジスタ５と、反転増幅回路であるインバータ６と、発振動作安定用のキャパシタ７，８とからなる。   Hereinafter, a preferred embodiment of the present invention will be described based on a schematic circuit diagram shown in FIG. The crystal oscillation circuit 1 is inserted in series with an externally attached crystal oscillator 2, a feedback resistor 3, and the feedback resistor 3, and is turned off when the crystal oscillation circuit 1 is on standby, and turned on when a start signal is inputted. Inserted between the transfer gate circuit 4, the connection point of the feedback resistor 3 and the transfer gate circuit 4 and the power supply, and is turned on when the crystal oscillation circuit 1 is on standby, and turned off when the start signal is input to the gate. It comprises a MOS transistor 5, an inverter 6 as an inverting amplifier, and capacitors 7 and 8 for stabilizing the oscillation operation.

水晶発振回路１の入力端Ａと接地間には、ＮＭＯＳトランジスタ９を挿入し、このＮＭＯＳトランジスタ９のゲートには、起動信号が入力するとモノパルス信号を出力するモノパルス発生回路１０の出力端を接続している。図２はモノパルス発生回路１０の構成を示し、ＤＦＦ（ディレイフリップフロップ）１１と、ＡＮＤ回路１２と、インバータ１３，１４とからなる。ＤＦＦ１１の入力端子Ｄには電源電圧が入力し、ＤＦＦ１１の入力端子ＣとＡＮＤ回路１２の一方の入力端に起動信号が入力し、また、ＤＦＦ１１の入力端子ＣＬにはインバータ１４からのクリア信号が入力する。さらに、ＤＦＦ１１の出力端子Ｑから、起動信号あるいはクリア信号の入力に応じてなされる出力は、ＡＮＤ回路１２の他方の入力端に入力し、ＡＮＤ回路１２の出力は、ＮＭＯＳトランジスタ９に出力されるとともに、インバータ１３に入力する。   An NMOS transistor 9 is inserted between the input terminal A of the crystal oscillation circuit 1 and the ground, and the output terminal of the monopulse generation circuit 10 that outputs a monopulse signal when an activation signal is input is connected to the gate of the NMOS transistor 9. ing. FIG. 2 shows a configuration of the monopulse generation circuit 10, which includes a DFF (delay flip-flop) 11, an AND circuit 12, and inverters 13 and 14. A power supply voltage is input to the input terminal D of the DFF 11, an activation signal is input to the input terminal C of the DFF 11 and one input terminal of the AND circuit 12, and a clear signal from the inverter 14 is input to the input terminal CL of the DFF 11. input. Further, the output made in response to the input of the activation signal or the clear signal from the output terminal Q of the DFF 11 is input to the other input terminal of the AND circuit 12, and the output of the AND circuit 12 is output to the NMOS transistor 9. At the same time, it is input to the inverter 13.

続いて、上述した水晶発振回路１の動作を説明する。水晶発振回路１の待機状態においては、ＭＯＳトランジスタ５がオン状態にあって、電源電圧が帰還抵抗３を介して入力端Ａに与えられるが、トランスファゲート回路４はオフ状態にあり、帰還路が形成されないので発振は開始しない。起動信号が入力すると、ＭＯＳトランジスタ５はオフとなって水晶発振回路１は電源電圧から切り離されるとともに、トランスファゲート回路４がオン動作して帰還路が形成され、発振が開始する。   Subsequently, the operation of the above-described crystal oscillation circuit 1 will be described. In the standby state of the crystal oscillation circuit 1, the MOS transistor 5 is in the on state and the power supply voltage is applied to the input terminal A through the feedback resistor 3, but the transfer gate circuit 4 is in the off state and the feedback path is Since it is not formed, oscillation does not start. When the activation signal is input, the MOS transistor 5 is turned off and the crystal oscillation circuit 1 is disconnected from the power supply voltage, and the transfer gate circuit 4 is turned on to form a feedback path and oscillation starts.

この時、起動信号はモノパルス発生回路１０にも入力し、ＤＦＦ１１の出力端Ｑから「Ｈ」が出力される。これによって、ＡＮＤ回路１２の両入力端に「Ｈ」が入力し、前記ＡＮＤ回路１２は「Ｈ」を出力する。この出力はＮＭＯＳトランジスタ９をオンさせ、これによって水晶発振回路１の入力端Ａの電位は下降する一方、各インバータ１３，１４を介してクリア信号としてＤＦＦ１１の入力端子ＣＬに入力し、出力端子Ｑの出力は「Ｌ」となる。これによって、ＡＮＤ回路１２の出力も「Ｌ」となり、前記ＮＭＯＳトランジスタ９はオフとなる。すなわち、モノパルス発生回路１０のＡＮＤ回路１２から出力されるモノパルス信号は、ＤＦＦ１１に起動信号が入力してからクリア信号が入力するまでの時間出力されて、この時間だけＮＭＯＳトランジスタ９がオンされる（図３参照）。   At this time, the activation signal is also input to the monopulse generation circuit 10, and “H” is output from the output terminal Q of the DFF 11. As a result, “H” is input to both input terminals of the AND circuit 12, and the AND circuit 12 outputs “H”. This output turns on the NMOS transistor 9, whereby the potential of the input terminal A of the crystal oscillation circuit 1 is lowered, and is input to the input terminal CL of the DFF 11 as a clear signal via the inverters 13 and 14, and the output terminal Q Becomes “L”. As a result, the output of the AND circuit 12 also becomes “L”, and the NMOS transistor 9 is turned off. That is, the monopulse signal output from the AND circuit 12 of the monopulse generation circuit 10 is output for a period of time from when the activation signal is input to the DFF 11 until the clear signal is input, and the NMOS transistor 9 is turned on only during this time ( (See FIG. 3).

ＮＭＯＳトランジスタ９がオフになると、水晶発振回路１の入力端Ａの電位の下降も停止し、通常の発振動作が継続されて、従来よりも早く安定した定常状態で発振する。発振動作が定常状態になるまでの時間は、従来の約１／３である。   When the NMOS transistor 9 is turned off, the drop of the potential at the input terminal A of the crystal oscillation circuit 1 is also stopped, and the normal oscillation operation is continued to oscillate in a stable steady state earlier than before. The time until the oscillation operation reaches a steady state is about 1/3 of the conventional time.

なお、本発明は上述の実施形態に限定されるものではなく、例えば、スイッチング素子はＮＭＯＳトランジスタ９に限らないが、入力端Ａの電位を下げるための通電時間の制御を考えると、モノパルス発生回路１０とＭＯＳトランジスタとの組み合わせが好適であり、ＭＯＳトランジスタはＮ型に限定されない。   The present invention is not limited to the above-described embodiment. For example, the switching element is not limited to the NMOS transistor 9, but considering the control of the energization time for lowering the potential of the input terminal A, the monopulse generation circuit A combination of 10 and a MOS transistor is suitable, and the MOS transistor is not limited to an N-type.

水晶発振回路の概略的な回路図。1 is a schematic circuit diagram of a crystal oscillation circuit. モノパルス発生回路の概略的な回路図Schematic circuit diagram of monopulse generator circuit 起動信号とモノパルス発生回路の出力との関係を示すグラフ。The graph which shows the relationship between a starting signal and the output of a monopulse generation circuit.

符号の説明Explanation of symbols

１ 水晶発振回路
２ 水晶振動子
３ 帰還抵抗
４ トランスファゲート回路
５ ＭＯＳトランジスタ
６ インバータ
７，８ キャパシタダイオード
９ ＮＭＯＳトランジスタ
１０ モノパルス発生回路
１１ ＤＦＦ
１２ ＡＮＤ回路
１３，１４ インバータ
DESCRIPTION OF SYMBOLS 1 Crystal oscillation circuit 2 Crystal oscillator 3 Feedback resistance 4 Transfer gate circuit 5 MOS transistor 6 Inverter 7, 8 Capacitor diode 9 NMOS transistor 10 Monopulse generation circuit 11 DFF
12 AND circuit 13, 14 Inverter

Claims (2)

水晶振動子の発振振幅を増幅させる増幅回路を備えた水晶発振回路において、
この水晶発振回路の入力端に、起動信号によって所定時間オン動作して前記入力端の電位を下げるスイッチング素子を設けた
ことを特徴とする水晶発振回路。 In a crystal oscillation circuit equipped with an amplifier circuit that amplifies the oscillation amplitude of the crystal resonator,
A crystal oscillation circuit, characterized in that a switching element is provided at the input end of the crystal oscillation circuit to turn on for a predetermined time by an activation signal to lower the potential at the input end. スイッチング素子は水晶発振回路の入力端と接地間に挿入されたトランジスタからなり、このトランジスタは、起動信号が入力するとモノパルスを発生するモノパルス発生回路によってオンオフ制御されることを特徴とする請求項１記載の水晶発振回路。
2. The switching element comprises a transistor inserted between the input terminal of the crystal oscillation circuit and the ground, and this transistor is ON / OFF controlled by a monopulse generating circuit that generates a monopulse when an activation signal is input. Crystal oscillation circuit.
JP2006145050A 2006-05-25 2006-05-25 Crystal oscillator circuit Pending JP2007318398A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103036506A (en) * 2011-09-28 2013-04-10 精工爱普生株式会社 Oscillator circuit, oscillator, electronic apparatus, and activation method of oscillator circuit
RU2498498C1 (en) * 2012-11-16 2013-11-10 Закрытое акционерное общество "Научно-производственный центр "Алмаз-Фазотрон" Low-noise crystal oscillator with automatic gain control
RU2748218C1 (en) * 2020-02-04 2021-05-21 Алексей Валерьевич Голубев Ultra-low-noise quartz oscillator

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59205802A (en) * 1983-05-10 1984-11-21 Fujitsu Ltd Oscillating circuit with start trigger
JPH02118312U (en) * 1989-03-09 1990-09-21

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59205802A (en) * 1983-05-10 1984-11-21 Fujitsu Ltd Oscillating circuit with start trigger
JPH02118312U (en) * 1989-03-09 1990-09-21

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103036506A (en) * 2011-09-28 2013-04-10 精工爱普生株式会社 Oscillator circuit, oscillator, electronic apparatus, and activation method of oscillator circuit
JP2013074510A (en) * 2011-09-28 2013-04-22 Seiko Epson Corp Oscillation circuit, oscillator, electronic apparatus, and method of starting oscillation circuit
RU2498498C1 (en) * 2012-11-16 2013-11-10 Закрытое акционерное общество "Научно-производственный центр "Алмаз-Фазотрон" Low-noise crystal oscillator with automatic gain control
RU2748218C1 (en) * 2020-02-04 2021-05-21 Алексей Валерьевич Голубев Ultra-low-noise quartz oscillator

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