JPS58225712A - Automatic gain control circuit - Google Patents
Automatic gain control circuitInfo
- Publication number
- JPS58225712A JPS58225712A JP10790482A JP10790482A JPS58225712A JP S58225712 A JPS58225712 A JP S58225712A JP 10790482 A JP10790482 A JP 10790482A JP 10790482 A JP10790482 A JP 10790482A JP S58225712 A JPS58225712 A JP S58225712A
- Authority
- JP
- Japan
- Prior art keywords
- output
- comparator
- amplifier
- circuit
- terminal
- 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.)
- Granted
Links
- 238000009499 grossing Methods 0.000 claims abstract description 11
- 230000007423 decrease Effects 0.000 abstract 3
- 238000010586 diagram Methods 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 2
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
- H03G3/301—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers the gain being continuously variable
- H03G3/3015—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers the gain being continuously variable using diodes or transistors
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Control Of Amplification And Gain Control (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は温度変化、素子のばらつきに依らず安定に動作
する自動利得制御回路（以下ＡＧＯ回路と称す）を提供
するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention provides an automatic gain control circuit (hereinafter referred to as an AGO circuit) that operates stably regardless of temperature changes and element variations.
図において１は入力端子、２は出力端子、３は増幅器、
４は整流素子、５は抵抗６とコンデンサ７とからなる平
滑回路、８は抵抗、９は可変抵抗、１０はトランジスタ
、１１は抵抗である。入力端子１に入力された信号は増
幅器３で増幅されｆ出力端子２に出力される。この出力
の一部は整流素子４で整流され、平滑回路５を介して直
流電圧に変換され、この電圧によりトランジスタ１ｏの
抵抗値を可変し、抵抗１１との抵抗比により損失量を変
化させ、出力が一定になるよう制御する。例えば、第２
図に示すように、ある入力レベルｖ１から出力が一定に
なるよう制御する場合には、トランジスタ１０の動作点
を変えるよう平滑回路５の出力電圧を可変抵抗９で調整
する。しかし、トランジスタ１０は温度によって素子特
性が変化するため、調整後温度が変化した場合には、第
２図の動作点Ｖ＋がずれてし壕う。又、トランジスタ１
０にバラツキがある場合、各回路毎に調整をしなければ
ならない欠点がある。In the figure, 1 is an input terminal, 2 is an output terminal, 3 is an amplifier,
4 is a rectifying element, 5 is a smoothing circuit consisting of a resistor 6 and a capacitor 7, 8 is a resistor, 9 is a variable resistor, 10 is a transistor, and 11 is a resistor. A signal input to input terminal 1 is amplified by amplifier 3 and output to f output terminal 2. A part of this output is rectified by the rectifying element 4 and converted to a DC voltage via the smoothing circuit 5, and this voltage changes the resistance value of the transistor 1o, and the amount of loss is changed by the resistance ratio with the resistor 11. Control the output to be constant. For example, the second
As shown in the figure, when controlling the output to be constant from a certain input level v1, the output voltage of the smoothing circuit 5 is adjusted by a variable resistor 9 so as to change the operating point of the transistor 10. However, since the element characteristics of the transistor 10 change depending on the temperature, if the temperature changes after adjustment, the operating point V+ in FIG. 2 will shift. Also, transistor 1
If there is variation in 0, there is a drawback that adjustment must be made for each circuit.
３べ゛
本発明は上記従来の欠点を除去するものであり、温度変
化、トランジスタのバラツキに依らず安定に動作する自
動利得制御回路を提供するものである０
第３図に本発明の一実施例を示す。第１図と同部品には
同一番号を記している。第３図において１２は比較器、
１３は基準電圧電源である。入力端子１に入力された信
号は増幅器３で増幅され、出力端子２に出力される。こ
の出力の一部は比較器１２の（」→端子に入力される。3. The present invention eliminates the above-mentioned conventional drawbacks and provides an automatic gain control circuit that operates stably regardless of temperature changes and transistor variations. FIG. 3 shows an embodiment of the present invention. Give an example. The same parts as in FIG. 1 are given the same numbers. In FIG. 3, 12 is a comparator;
13 is a reference voltage power supply. A signal input to input terminal 1 is amplified by amplifier 3 and output to output terminal 2. A part of this output is input to the (''→ terminal of the comparator 12).
比較器１２の（→端子には基準電圧が印加される。この
基準電圧は比較器１２の出力が第２図に示すところの動
作点Ｖ１以上の時に（」→となるように設定されている
。比較器１２の出力は平滑回路５を介してトランジスタ
１０のベースに印加されるが、Ｉ・ランジスタ１０の抵
抗はベース電圧が高くなるにつれて小さくなる。したが
って、入力端子１に第２図の７１以上のレベルが入力さ
れた場合には、比較器１２の出力は（刊となり、トラン
ジスタ１０の抵抗は小さくなり、抵抗１１との比で入力
レベルが減衰し、増幅器３の出力が小さくなる。同時に
比較器１２の出力は増幅器３の出力レベルが基準電圧以
下になった時点で（→の電圧となる方向に動作し、再度
初期の状態に戻る。A reference voltage is applied to the (→ terminal of the comparator 12. This reference voltage is set so that when the output of the comparator 12 is at or above the operating point V1 shown in FIG. The output of the comparator 12 is applied to the base of the transistor 10 via the smoothing circuit 5, but the resistance of the I transistor 10 becomes smaller as the base voltage increases. When the above level is input, the output of the comparator 12 becomes When the output level of the amplifier 3 becomes lower than the reference voltage, the output of the comparator 12 operates in the direction of the voltage (→) and returns to the initial state again.
第４図ａ１１〕、Ｃはそれぞれ第３図における増幅器３
の出力、比較器１２の出力および平滑回路５の出力を示
している。なお、比較器１２の動作は第４図すの如くに
なり、増幅器３の出力変動を抑えるため、平滑回路５０
時定数は長くしている。Fig. 4 a11], C are the amplifiers 3 in Fig. 3, respectively.
, the output of the comparator 12, and the output of the smoothing circuit 5. The operation of the comparator 12 is as shown in FIG.
The time constant is long.
上記の回路動作により、増幅器３の出力は一定となる。Due to the above circuit operation, the output of the amplifier 3 becomes constant.
ここで温度が変化したり、トランジスタ１０の抵抗にバ
ラツキがあっても、増幅器３の出力は比較器１２に印加
され墨監視されるため、温度変化まだはトランジスタ１
０のバラツキにかかわらず、安定した出力が得られるも
のである。Even if the temperature changes or there is a variation in the resistance of the transistor 10, the output of the amplifier 3 is applied to the comparator 12 and monitored,
A stable output can be obtained regardless of the variation in zero.
なお、上記実施例においてトランジスタ１０を用いてい
るが、トランジスタに限らず、平滑回路５の出力電圧に
応じてインピーダンスが変化するインピーダンス可変素
子又は、インピーダンス可変回路であればよいものであ
る。Although the transistor 10 is used in the above embodiment, it is not limited to a transistor, and any variable impedance element or variable impedance circuit whose impedance changes depending on the output voltage of the smoothing circuit 5 may be used.
５ベシ
本発明は上記のような構成であり、本発明によれば無調
整で、温度変化まだは素子のバラツキにかかわらず、安
定に動作する自動利得制御回路が実現できるものである
・The present invention has the above configuration, and according to the present invention, it is possible to realize an automatic gain control circuit that operates stably without adjustment, regardless of temperature changes and element variations.
第１図は従来の自動利得制御回路の電気回路図、第２図
は同回路の入出力特性図、第３図は本発明の一実施例に
おける自動利得制御回路の電気回路図、第４図ａ１ｂ、
Ｃは同回路の各部の波形図である。
１ ・入力端子、２・・出力端子、３・・増幅器、５・
・・平滑回路、６・・・抵抗、７・・・コンデンサ、１
０・・・トランジスタ、１１・・抵抗、１２・・・比較
器、１３・・・基準電圧電源〇
代理人の氏名 弁理士 中 尾 敏 男 ほか１名第１
図
■
第２図
ｌ
入力ｔ／’・・ルFig. 1 is an electric circuit diagram of a conventional automatic gain control circuit, Fig. 2 is an input/output characteristic diagram of the same circuit, Fig. 3 is an electric circuit diagram of an automatic gain control circuit according to an embodiment of the present invention, and Fig. 4 a1b,
C is a waveform diagram of each part of the circuit. 1. Input terminal, 2.. Output terminal, 3.. Amplifier, 5.
...Smoothing circuit, 6...Resistor, 7...Capacitor, 1
0...Transistor, 11...Resistor, 12...Comparator, 13...Reference voltage power supply Name of agent Patent attorney Toshio Nakao and 1 other person 1st
Figure ■ Figure 2 l Input t/'...le
Claims (1)
この増幅器の出力と基準電圧とを比較する比較器と、こ
の比較器の出力を平滑する平滑回路と、上記抵抗と上記
増幅器の入力端の接続点とアースとの間に接続されたイ
ンピーダンス可変素子まだは、インピーダンス可変回路
とを有し、上記平滑回路の出力電圧によって上記インピ
ーダンス可変素子又はインピーダンス可変回路のインピ
ーダンスを変化させ、上記入力信号を上記抵抗と上記イ
ンピーダンス可変素子又はインピーダンス可変回路で分
圧することを特徴とする自動利得制御回路・an amplifier that amplifies an input signal applied through a resistor;
A comparator that compares the output of this amplifier with a reference voltage, a smoothing circuit that smoothes the output of this comparator, and a variable impedance element connected between the connection point of the resistor and the input end of the amplifier and ground. Still, it has a variable impedance circuit, and changes the impedance of the variable impedance element or variable impedance circuit according to the output voltage of the smoothing circuit, and divides the input signal by the resistor and the variable impedance element or variable impedance circuit. An automatic gain control circuit characterized by
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10790482A JPS58225712A (en) | 1982-06-23 | 1982-06-23 | Automatic gain control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10790482A JPS58225712A (en) | 1982-06-23 | 1982-06-23 | Automatic gain control circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58225712A true JPS58225712A (en) | 1983-12-27 |
| JPH0141047B2 JPH0141047B2 (en) | 1989-09-01 |
Family
ID=14471009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10790482A Granted JPS58225712A (en) | 1982-06-23 | 1982-06-23 | Automatic gain control circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58225712A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59108413A (en) * | 1982-12-14 | 1984-06-22 | Rohm Co Ltd | Automatic level adjusting circuit |
| CN101964169A (en) * | 2009-07-23 | 2011-02-02 | 瑞萨电子株式会社 | Signal-line driving circuit and liquid crystal indicator |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50104846A (en) * | 1974-01-21 | 1975-08-19 | ||
| JPS5437616A (en) * | 1977-08-31 | 1979-03-20 | Fujitsu Ltd | Input level supervising system for variable attenuator |
-
1982
- 1982-06-23 JP JP10790482A patent/JPS58225712A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50104846A (en) * | 1974-01-21 | 1975-08-19 | ||
| JPS5437616A (en) * | 1977-08-31 | 1979-03-20 | Fujitsu Ltd | Input level supervising system for variable attenuator |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59108413A (en) * | 1982-12-14 | 1984-06-22 | Rohm Co Ltd | Automatic level adjusting circuit |
| JPH041524B2 (en) * | 1982-12-14 | 1992-01-13 | Rohm Kk | |
| CN101964169A (en) * | 2009-07-23 | 2011-02-02 | 瑞萨电子株式会社 | Signal-line driving circuit and liquid crystal indicator |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0141047B2 (en) | 1989-09-01 |
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