JPH0843456A - Ac level detection circuit - Google Patents
Ac level detection circuitInfo
- Publication number
- JPH0843456A JPH0843456A JP17785894A JP17785894A JPH0843456A JP H0843456 A JPH0843456 A JP H0843456A JP 17785894 A JP17785894 A JP 17785894A JP 17785894 A JP17785894 A JP 17785894A JP H0843456 A JPH0843456 A JP H0843456A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor diode
- diode
- differential amplifier
- level
- signal
- 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
- 238000001514 detection method Methods 0.000 title claims abstract description 26
- 230000003321 amplification Effects 0.000 claims abstract description 5
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 5
- 239000004065 semiconductor Substances 0.000 claims description 35
- 238000010586 diagram Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 1
Landscapes
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は交流信号のレベル検出回
路に関し、特に温度に対して安定な検出回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC signal level detection circuit, and more particularly to a temperature stable detection circuit.
【０００２】[0002]
【従来の技術】従来の温度補償型レベル検出回路では、
図２に示すように交流信号１のレベルを検波ダイオード
２によって検出する際に、微少交流電圧まで検出する場
合に、ダイオード２の順方向にわずかの電流が流れるま
で電圧源８と抵抗４でバイアスを与え、かつ第２のダイ
オード３に抵抗５でバイアスを与え、ダイオード２と３
を同特性にし、抵抗４と５を同じ値とし、差動増幅器９
よって両ダイオードの端子電圧の差を増幅して出力する
ことにより、温度変化によるダイオード２の端子電圧の
変動を打ち消すようにしている。この図２の回路では、
交流信号１の大きさによってダイオード２の端子電圧が
変化し、ひいては差動増幅器９の出力が交流信号１の大
きさに応じて変動することを利用して、交流信号１のレ
ベルを検出している。2. Description of the Related Art In a conventional temperature compensation type level detection circuit,
As shown in FIG. 2, when detecting the level of the AC signal 1 by the detection diode 2, when detecting a minute AC voltage, the voltage source 8 and the resistor 4 bias until a slight current flows in the forward direction of the diode 2. And biasing the second diode 3 with the resistor 5
To have the same characteristics, resistors 4 and 5 have the same value, and the differential amplifier 9
Therefore, by amplifying and outputting the difference between the terminal voltages of both diodes, variations in the terminal voltage of the diode 2 due to temperature changes are canceled. In the circuit of FIG.
The level of the AC signal 1 is detected by utilizing the fact that the terminal voltage of the diode 2 changes according to the magnitude of the AC signal 1 and that the output of the differential amplifier 9 fluctuates according to the magnitude of the AC signal 1. I have.
【０００３】温度によってダイオード２のバイアス点が
変動することは、図２の回路の採用によって回避できる
が、図３に示すようにダイオードでは電圧−電流特性の
微分値が温度によって変化し、同じバイアス電流でも検
波出力は低温ほど小さくなる。The variation of the bias point of the diode 2 due to temperature can be avoided by employing the circuit shown in FIG. 2. However, as shown in FIG. 3, in the diode, the differential value of the voltage-current characteristic changes with temperature, and Even with current, the detection output decreases as the temperature decreases.
【０００４】従って従来は、図２のように、抵抗１０と
サーミスタ１１によって温度が上昇するほど分圧比の大
となる分圧回路を設けて、上記の検波効率の変動を補償
した結果を出力端子１２に出していた。Therefore, conventionally, as shown in FIG. 2, a voltage dividing circuit having a larger voltage dividing ratio as the temperature rises by the resistor 10 and the thermistor 11 is provided, and the result of compensating the fluctuation of the detection efficiency is output to the output terminal. I had 12
【０００５】[0005]
【発明が解決しようとする課題】この従来の方式では、
温度補償用の素子、すなわち温度に敏感な素子がダイオ
ード３とサーミスタ１１との２個であり、実装上はこの
両者を検波ダイオード２に熱的に結合する必要があっ
て、構造上複雑となる。また、本来、温度特性の異なる
ダイオードとサーミスタを互いに特性を打ち消すように
調整することはやっかいである。In this conventional system,
There are two temperature-compensating elements, that is, temperature-sensitive elements, the diode 3 and the thermistor 11, and it is necessary to thermally couple both of them to the detection diode 2 for mounting, which complicates the structure. . Also, it is originally troublesome to adjust a diode and a thermistor having different temperature characteristics so that the characteristics cancel each other.
【０００６】[0006]
【課題を解決するための手段】前述の課題を解決するた
めに本発明は次の手段を提供する。In order to solve the above-mentioned problems, the present invention provides the following means.
【０００７】交流信号を第１の半導体ダイオードによ
って検波することによって該交流信号の大きさを検出す
る回路であって、該第１の半導体ダイオードに最適のバ
イアスを与えるために電流バイアスを加え、かつ前記第
１の半導体ダイオードと同じ特性の第２の半導体ダイオ
ードに同じ量のバイアス電流を与え、両半導体ダイオー
ドに流れる直流電流または両半導体ダイオードの端子電
圧を差動増幅器に加え、この差動増幅器の出力が前記第
１の半導体ダイオードに印加される交流信号の大きさに
応じて変ることを利用し、該差動増幅器の出力によっ
て、前記交流信号のレベルを検出し、前記第１の半導体
ダイオードのバイアス点の温度変化を補償するようにし
たレベル検出回路において、前記第２の半導体ダイオー
ドの端子電圧に応じて、前記差動増幅器を含むレベル信
号増幅系の利得を制御する交流レベル検出回路。A circuit for detecting the magnitude of the alternating current signal by detecting the alternating current signal by the first semiconductor diode, wherein a current bias is applied to give an optimum bias to the first semiconductor diode, and The same amount of bias current is applied to the second semiconductor diode having the same characteristics as the first semiconductor diode, and the direct current flowing through both semiconductor diodes or the terminal voltage of both semiconductor diodes is applied to the differential amplifier. Utilizing the fact that the output changes according to the magnitude of the AC signal applied to the first semiconductor diode, the level of the AC signal is detected by the output of the differential amplifier, and the output of the first semiconductor diode of the first semiconductor diode is detected. In a level detection circuit configured to compensate for a temperature change at a bias point, the level detection circuit according to the terminal voltage of the second semiconductor diode AC level detector circuit for controlling the gain of the level signal amplification system comprising the differential amplifier.
【０００８】前記第１の半導体ダイオードに第１の抵
抗を直列に接続し、前記第２の半導体ダイオードに第２
の抵抗を直列に接続し、前記第１の半導体ダイオードお
よび第１の抵抗でなる第１の直流回路ならびに前記第２
の半導体ダイオードおよび第２の抵抗でなる第２の直流
回路を並列に接続して前記電流バイアス用の直流電圧を
加え、前記第１の半導体ダイオードおよび第１の抵抗の
接続点である第１の節点と前記第２の半導体ダイオード
および第２の抵抗の接続点である第２の節点とを前記差
動増幅器の差動入力端子にそれぞれ接続したことを特徴
とする上記に記載の交流レベル検出回路。[0008] A first resistor is connected in series to the first semiconductor diode, and a second resistor is connected to the second semiconductor diode.
Connected in series with each other, and a first DC circuit composed of the first semiconductor diode and the first resistor, and the second DC circuit.
A second DC circuit composed of a semiconductor diode and a second resistor is connected in parallel, a DC voltage for the current bias is applied, and a first point, which is a connection point between the first semiconductor diode and the first resistor, is connected. The AC level detection circuit as described above, wherein a node and a second node, which is a connection point between the second semiconductor diode and the second resistor, are respectively connected to a differential input terminal of the differential amplifier. .
【０００９】前記レベル信号増幅系は、前記差動増幅
器と、この差動増幅器の出力を増幅する利得可変増幅器
とでなり、前記第２の半導体ダイオードの端子電圧に応
じて該利得可変増幅器の利得を制御することを特徴とす
る上記またはに記載の交流レベル検出回路。The level signal amplifying system comprises the differential amplifier and a variable gain amplifier for amplifying the output of the differential amplifier, and the gain of the variable gain amplifier depends on the terminal voltage of the second semiconductor diode. The AC level detection circuit according to the above or above, which controls
【００１０】前記第２の半導体ダイオードの端子電圧
を第２の差動増幅器で増幅して前記利得可変増幅器の利
得制御端子に加えることを特徴とする上記に記載の交
流レベル検出回路。The AC level detection circuit as described above, wherein the terminal voltage of the second semiconductor diode is amplified by a second differential amplifier and applied to a gain control terminal of the variable gain amplifier.
【００１１】[0011]
【作用】本発明では、第２のダイオードの端子電圧でレ
ベル信号増幅系の利得を制御しているので、ダイオード
の検波効率が温度によって変動しても、レベル信号増幅
系においてその変動を補償できる。In the present invention, since the gain of the level signal amplification system is controlled by the terminal voltage of the second diode, even if the detection efficiency of the diode fluctuates with temperature, the fluctuation can be compensated for in the level signal amplification system. .
【００１２】[0012]
【実施例】図１は本発明の一実施例の回路図である。FIG. 1 is a circuit diagram of an embodiment of the present invention.
【００１３】補償用のダイオード３の端子電圧は差動増
幅器２１によって増幅されて可変利得増幅器２２の利得
を制御する。この可変利得増幅器２２は２つのダイオー
ド２，３の端子電圧の差を増幅する差動増幅器９の出力
を増幅して出力する。The terminal voltage of the compensating diode 3 is amplified by the differential amplifier 21 to control the gain of the variable gain amplifier 22. The variable gain amplifier 22 amplifies and outputs the output of the differential amplifier 9 which amplifies the difference between the terminal voltages of the two diodes 2 and 3.
【００１４】例えば、低温になるほどダイオード２，３
の端子電圧を上昇し、これを差動増幅器２１によって反
転増幅した出力は温度に比例した電圧となり、これによ
って可変利得増幅器２２の利得が上昇する方向に制御す
る。この制御電圧と利得の関係をあらかじめ検波ダイオ
ードの電流・電圧の微分値の温度変化に対して適当に選
んでおけば、温度による検波効率の変化を打ち消せる。For example, the lower the temperature is, the diodes 2, 3
, And the output obtained by inverting and amplifying the voltage by the differential amplifier 21 becomes a voltage proportional to the temperature, whereby the gain of the variable gain amplifier 22 is controlled to increase. If the relationship between the control voltage and the gain is properly selected in advance with respect to the temperature change of the differential value of the current / voltage of the detection diode, the change of the detection efficiency due to the temperature can be canceled.
【００１５】[0015]
【発明の効果】以上の説明したように、本発明は、バイ
アス電流補償用のダイオードの端子電圧の温度による変
化によって検波効率の変化を補償するので、別の補償素
子を必要とせず、温度に敏感な素子を検波ダイオードと
補償用ダイオードとの２個に限定できるので構造上簡単
になり、また補償調整が容易となる利点を有する。As described above, the present invention compensates for the change in the detection efficiency by the change in the terminal voltage of the bias current compensating diode due to the temperature, so that another compensating element is not required and the temperature is reduced. Since the number of sensitive elements can be limited to two, that is, the detection diode and the compensation diode, there is an advantage that the structure is simple and the compensation adjustment is easy.
【図１】本発明の一実施例の回路図。FIG. 1 is a circuit diagram of an embodiment of the present invention.
【図２】従来例の回路図。FIG. 2 is a circuit diagram of a conventional example.
【図３】温度補償作用を説明するためのダイオードの電
圧・電流静特性。FIG. 3 is a diagram showing static voltage / current characteristics of a diode for explaining a temperature compensation operation.
２ 検波用ダイオード ３ 補償用ダイオード ９，２１ 差動増幅器 ２２ 可変利得増幅器 2 Detection diode 3 Compensation diode 9, 21 Differential amplifier 22 Variable gain amplifier
Claims (4)
て検波することによって該交流信号の大きさを検出する
回路であって、該第１の半導体ダイオードに最適のバイ
アスを与えるために電流バイアスを加え、かつ前記第１
の半導体ダイオードと同じ特性の第２の半導体ダイオー
ドに同じ量のバイアス電流を与え、両半導体ダイオード
に流れる直流電流または両半導体ダイオードの端子電圧
を差動増幅器に加え、この差動増幅器の出力が前記第１
の半導体ダイオードに印加される交流信号の大きさに応
じて変ることを利用し、該差動増幅器の出力によって前
記交流信号のレベルを検出し、前記第１の半導体ダイオ
ードのバイアス点の温度変化を補償するようにしたレベ
ル検出回路において、前記第２の半導体ダイオードの端
子電圧に応じて、前記差動増幅器を含むレベル信号増幅
系の利得を制御する交流レベル検出回路。1. A circuit for detecting the magnitude of an AC signal by detecting an AC signal with a first semiconductor diode, wherein a current bias is applied to apply an optimum bias to the first semiconductor diode. And the first
The same amount of bias current is applied to a second semiconductor diode having the same characteristics as the semiconductor diode of the above, and a DC current flowing through both semiconductor diodes or a terminal voltage of both semiconductor diodes is applied to a differential amplifier. First
Utilizing the fact that it changes according to the magnitude of the AC signal applied to the semiconductor diode, the level of the AC signal is detected by the output of the differential amplifier, and the temperature change of the bias point of the first semiconductor diode is detected. An AC level detection circuit for controlling a gain of a level signal amplification system including the differential amplifier according to a terminal voltage of the second semiconductor diode.
を直列に接続し、前記第２の半導体ダイオードに第２の
抵抗を直列に接続し、前記第１の半導体ダイオードおよ
び第１の抵抗でなる第１の直流回路ならびに前記第２の
半導体ダイオードおよび第２の抵抗でなる第２の直流回
路を並列に接続して前記電流バイアス用の直流電圧を加
え、前記第１の半導体ダイオードおよび第１の抵抗の接
続点である第１の節点と前記第２の半導体ダイオードお
よび第２の抵抗の接続点である第２の節点とを前記差動
増幅器の差動入力端子にそれぞれ接続したことを特徴と
する請求項１に記載の交流レベル検出回路。2. The first semiconductor diode has a first resistor connected in series, the second semiconductor diode has a second resistor connected in series, and the first semiconductor diode and the first resistor are connected in series. And a second DC circuit consisting of the second semiconductor diode and the second resistor are connected in parallel to apply the DC voltage for current bias, and the first semiconductor diode and the second A first node which is a connection point of the first resistor and a second node which is a connection point of the second semiconductor diode and the second resistor are connected to a differential input terminal of the differential amplifier, respectively. The AC level detection circuit according to claim 1, wherein:
と、この差動増幅器の出力を増幅する利得可変増幅器と
でなり、前記第２の半導体ダイオードの端子電圧に応じ
て該利得可変増幅器の利得を制御することを特徴とする
請求項１または２に記載の交流レベル検出回路。3. The level signal amplifying system includes the differential amplifier and a variable gain amplifier for amplifying an output of the differential amplifier, and the variable gain amplifier according to a terminal voltage of the second semiconductor diode. The AC level detection circuit according to claim 1, wherein the gain of the AC level is controlled.
第２の差動増幅器で増幅して前記利得可変増幅器の利得
制御端子に加えることを特徴とする請求項３に記載の交
流レベル検出回路。4. The AC level detecting circuit according to claim 3, wherein a terminal voltage of said second semiconductor diode is amplified by a second differential amplifier and applied to a gain control terminal of said variable gain amplifier. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17785894A JP2576414B2 (en) | 1994-07-29 | 1994-07-29 | AC level detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17785894A JP2576414B2 (en) | 1994-07-29 | 1994-07-29 | AC level detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0843456A true JPH0843456A (en) | 1996-02-16 |
| JP2576414B2 JP2576414B2 (en) | 1997-01-29 |
Family
ID=16038324
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17785894A Expired - Lifetime JP2576414B2 (en) | 1994-07-29 | 1994-07-29 | AC level detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2576414B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009145277A (en) * | 2007-12-17 | 2009-07-02 | Fujitsu Telecom Networks Ltd | Current detection circuit |
| JP2013090144A (en) * | 2011-10-18 | 2013-05-13 | Fujitsu Ltd | Signal detection circuit |
-
1994
- 1994-07-29 JP JP17785894A patent/JP2576414B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009145277A (en) * | 2007-12-17 | 2009-07-02 | Fujitsu Telecom Networks Ltd | Current detection circuit |
| JP2013090144A (en) * | 2011-10-18 | 2013-05-13 | Fujitsu Ltd | Signal detection circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2576414B2 (en) | 1997-01-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 19960910 |