JP2621798B2 - Level detection circuit - Google Patents
Level detection circuitInfo
- Publication number
- JP2621798B2 JP2621798B2 JP12224094A JP12224094A JP2621798B2 JP 2621798 B2 JP2621798 B2 JP 2621798B2 JP 12224094 A JP12224094 A JP 12224094A JP 12224094 A JP12224094 A JP 12224094A JP 2621798 B2 JP2621798 B2 JP 2621798B2
- Authority
- JP
- Japan
- Prior art keywords
- diode
- capacitor
- input terminal
- detection circuit
- level detection
- 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
- Measurement Of Current Or Voltage (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は交流信号のレベルを検出
するレベル検出回路に関し、特に、温度変化に対して安
定な検出出力を有するレベル検出回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a level detection circuit for detecting a level of an AC signal, and more particularly to a level detection circuit having a detection output which is stable against a temperature change.
【０００２】[0002]
【従来の技術】従来のレベル検出回路は、図２に示すよ
うに、入力端子１に第１コンデンサ４の一端を接続し、
第１コンデンサ４の他端を第１ダイオード２のアノード
及びコイル５の一端に接続し、第１ダイオード２のカソ
ードを出力端子８に接続し、コイル５の他端を第２ダイ
オード３のアノード及び第２抵抗９の一端に接続し、第
２ダイオードのカソードを接地し、第２抵抗９の他端を
直流電圧源１０の正の端子に接続し、直流電圧源１０の
負の端子を接地し、出力端子８と接地間に第１抵抗６と
第２コンデンサ７を並列に接続して構成されている。2. Description of the Related Art In a conventional level detection circuit, as shown in FIG. 2, one end of a first capacitor 4 is connected to an input terminal 1;
The other end of the first capacitor 4 is connected to the anode of the first diode 2 and one end of the coil 5, the cathode of the first diode 2 is connected to the output terminal 8, and the other end of the coil 5 is connected to the anode of the second diode 3 and One end of the second resistor 9 is connected, the cathode of the second diode is grounded, the other end of the second resistor 9 is connected to the positive terminal of the DC voltage source 10, and the negative terminal of the DC voltage source 10 is grounded. The first resistor 6 and the second capacitor 7 are connected in parallel between the output terminal 8 and the ground.
【０００３】図２において、第２ダイオード３に対し、
直流電圧源１０と第２抵抗９によってバイアス電流を加
え、第２ダイオード３の端子電圧を第１ダイオード２に
加える。この際、第１ダイオード２と第２ダイオード３
の特性を等しく選ぶことにより、第２ダイオード３の端
子電圧が第１ダイオード２のバイアス電圧をその立上り
電圧の温度変化に追随して変化させ得るので、温度に対
して安定な検出回路が得られるというものであった。In FIG. 2, for the second diode 3,
A bias current is applied by the DC voltage source 10 and the second resistor 9, and the terminal voltage of the second diode 3 is applied to the first diode 2. At this time, the first diode 2 and the second diode 3
By selecting the same characteristics, the terminal voltage of the second diode 3 can change the bias voltage of the first diode 2 following the temperature change of the rising voltage, so that a temperature-stable detection circuit can be obtained. It was that.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、この従
来のレベル検出回路では、第１ダイオード２と第２ダイ
オード３の直流帰路は第２抵抗９を含み、入力端子１に
加えられた交流信号１４の増減によって変化する第１ダ
イオード２と第２ダイオード３の平均電流の変化が第２
抵抗９によってバイアス電圧の変化を生じて最適点から
ずれるという欠点があった。また、平均電流の変化に起
因するバイアス電圧の変化を減少するために抵抗９を小
さい値にすると、図３において、負荷直線３１が負荷直
線３２となり、かつ、直流電圧源１０の電圧ＶＣ１を電
圧ＶＣ２に下げなければ、室温において、最適のバイア
ス電圧ＶＢが得られず、この状態で温度が−２０℃から
＋６０℃に変化すると、図３に示したように、ダイオー
ド電流がＩＢ２からＩＢ３へと大幅に変化してしまう。However, in this conventional level detection circuit, the DC return path of the first diode 2 and the second diode 3 includes the second resistor 9 so as to detect the AC signal 14 applied to the input terminal 1. The change of the average current of the first diode 2 and the second diode 3 which changes by
There is a disadvantage that the bias voltage is changed by the resistor 9 and deviates from the optimum point. When the resistance 9 is set to a small value in order to reduce the change in the bias voltage caused by the change in the average current, the load straight line 31 becomes the load straight line 32 and the voltage VC1 of the DC voltage source 10 is changed to the voltage in FIG. Unless lowered to VC2, the optimum bias voltage VB cannot be obtained at room temperature. When the temperature changes from -20 ° C to + 60 ° C in this state, the diode current changes from IB2 to IB3 as shown in FIG. It changes drastically.
【０００５】本発明の目的は、交流信号が増減しても、
バイアス電圧の変化を少なくし、また、温度が変化して
も、バイアス電圧が大幅に変化しないレベル検出回路を
提供することにある。[0005] An object of the present invention is to reduce or increase an AC signal.
It is an object of the present invention to provide a level detection circuit in which a change in a bias voltage is reduced and a bias voltage does not largely change even when a temperature changes.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、本発明は、入力端子に第１コンデンサの一端を接続
し、第１コンデンサの他端を第１ダイオードのアノード
及びコイルの一端に接続し、第１ダイオードのカソード
を出力端子に接続し、コイルの他端を、入力側が高イン
ピーダンスで出力側が低インピーダンスであるインピー
ダンス変換器の出力端及び第３コンデンサの一端に接続
し、第３コンデンサの他端を接地し、インピーダンス変
換器の入力端に第２ダイオードのアノード及び定電流源
の一端を接続し、第２ダイオードのカソード及び定電流
源の他端を接地し、出力端子と接地間に第１抵抗及び第
２コンデンサを並列に接続したものである。In order to achieve the above-mentioned object, according to the present invention, one end of a first capacitor is connected to an input terminal, and the other end of the first capacitor is connected to an anode of a first diode and one end of a coil. And the other end of the coil is connected to the output end of an impedance converter having a high impedance on the input side and a low impedance on the output side, and to one end of a third capacitor. The other end of the capacitor is grounded, the anode of the second diode and one end of the constant current source are connected to the input end of the impedance converter, the cathode of the second diode and the other end of the constant current source are grounded, and the output terminal is grounded. A first resistor and a second capacitor are connected in parallel between them.
【０００７】本発明は、インピーダンス変換器を利得１
の増幅器で構成したものである。また、本発明は、利得
１の増幅器を、正の入力端と負の入力端を有し負の入力
端を出力端に接続し正の入力端を入力端とした増幅器で
構成したものである。According to the present invention, the impedance converter has a gain of 1.
Of the amplifier. According to the present invention, an amplifier having a gain of 1 includes an amplifier having a positive input terminal and a negative input terminal, the negative input terminal being connected to the output terminal, and the positive input terminal being the input terminal. .
【０００８】[0008]
【作用】図１において、第２ダイオード３は定電流源１
２により駆動されるので、温度が変化しても、第２ダイ
オード３に流れる電流は一定であり、図３において、負
荷直線は直線３３となる。利得１の増幅器１１は第２ダ
イオード３の端子電圧をそのままの電圧で低インピーダ
ンスに変換し、コイル５を通して第１ダイオード２に供
給する。In FIG. 1, the second diode 3 is a constant current source 1
2, the current flowing through the second diode 3 is constant even if the temperature changes, and the load straight line becomes a straight line 33 in FIG. The amplifier 11 having a gain of 1 converts the terminal voltage of the second diode 3 into a low impedance with the voltage as it is, and supplies it to the first diode 2 through the coil 5.
【０００９】したがって、温度が大幅に変化しても、第
１ダイオード２には同じバイアス電流が流れるようなバ
イアス電圧が供給され、かつ、交流信号が増大してもバ
イアス電圧が低下するという現象は発生しない。Therefore, even if the temperature greatly changes, the first diode 2 is kept under such a condition that the same bias current flows.
The phenomenon that the bias voltage decreases even when the bias voltage is supplied and the AC signal increases does not occur.
【００１０】[0010]
【実施例】次に、本発明について図面を参照して説明す
る。図１は本発明の一実施例のレベル検出回路である。Next, the present invention will be described with reference to the drawings. FIG. 1 shows a level detection circuit according to one embodiment of the present invention.
【００１１】本実施例は、図１に示すように、入力端子
１に第１コンデンサ４の一端を接続し、第１コンデンサ
４の他端を第１ダイオード２のアノード及びコイル５の
一端に接続し、第１ダイオード２のカソードを出力端子
８に接続し、コイル５の他端を利得１の増幅器１１の出
力端及び第３コンデンサ１３の一端に接続し、第３コン
デンサ１３の他端を接地し、利得１の増幅器１１の負の
入力端を利得１の増幅器１１の出力端に接続し、利得１
の増幅器１１の正の入力端に第２ダイオード３のアノー
ド及び定電流源１２の一端を接続し、第２ダイオード３
のカソード及び定電流源１２の他端を接地し、出力端子
８と接地間に第１抵抗６及び第２コンデンサ７を並列に
接続して構成されている。In this embodiment, as shown in FIG. 1, one end of a first capacitor 4 is connected to an input terminal 1, and the other end of the first capacitor 4 is connected to an anode of a first diode 2 and one end of a coil 5. Then, the cathode of the first diode 2 is connected to the output terminal 8, the other end of the coil 5 is connected to the output end of the amplifier 11 having a gain of 1 and one end of the third capacitor 13, and the other end of the third capacitor 13 is grounded. Then, the negative input terminal of the gain 1 amplifier 11 is connected to the output terminal of the gain 1 amplifier 11,
The anode of the second diode 3 and one end of the constant current source 12 are connected to the positive input terminal of the
And the other end of the constant current source 12 are grounded, and the first resistor 6 and the second capacitor 7 are connected in parallel between the output terminal 8 and the ground.
【００１２】図１において、第２ダイオード３は定電流
源１２により駆動されるので、温度が変化しても、第２
ダイオード３に流れる電流は一定であり、図３におい
て、負荷直線は直線３３となる。利得１の増幅器１１は
第２ダイオード３の端子電圧をそのままの電圧で低イン
ピーダンスに変換し、コイル５を通して第１ダイオード
２に供給する。In FIG. 1, since the second diode 3 is driven by the constant current source 12, even if the temperature changes,
The current flowing through the diode 3 is constant, and the load straight line is a straight line 33 in FIG. The amplifier 11 having a gain of 1 converts the terminal voltage of the second diode 3 into a low impedance with the voltage as it is, and supplies it to the first diode 2 through the coil 5.
【００１３】したがって、温度が大幅に変化しても、第
１ダイオード２には同じバイアス電流が流れるようなバ
イアス電圧が供給され、かつ、交流信号１４が増大して
もバイアス電圧が低下するという現象は発生しない。Therefore, even if the temperature greatly changes, the first diode 2 is kept under such a condition that the same bias current flows.
Even when the bias voltage is supplied and the AC signal 14 increases, the phenomenon that the bias voltage decreases does not occur.
【００１４】[0014]
【発明の効果】本発明は、以上説明したように構成され
ているので、交流信号が増減しても、バイアス電圧の変
化が少なくなり、また、温度が変化しても、バイアス電
圧が大幅に変化しないという効果を有する。Since the present invention is constructed as described above, the change in the bias voltage is reduced even if the AC signal is increased or decreased, and the bias voltage is largely changed even if the temperature is changed. It has the effect of not changing.
【図１】本発明の一実施例のレベル検出回路を示す図で
ある。FIG. 1 is a diagram showing a level detection circuit according to one embodiment of the present invention.
【図２】従来のレベル検出回路を示す図である。FIG. 2 is a diagram illustrating a conventional level detection circuit.
【図３】ダイオードの静特性の温度変化を示す図であ
る。FIG. 3 is a diagram showing a temperature change of a static characteristic of a diode.
１ 入力端子 ２ 第１ダイオード ３ 第２ダイオード ４ 第１コンデンサ ５ コイル ６ 第１抵抗 ７ 第２コンデンサ ８ 出力端子 １１ 利得１の増幅器 １２ 定電流源 １３ 第３コンデンサ １４ 交流信号 DESCRIPTION OF SYMBOLS 1 Input terminal 2 1st diode 3 2nd diode 4 1st capacitor 5 Coil 6 1st resistance 7 2nd capacitor 8 Output terminal 11 Amplifier of 1 gain 12 Constant current source 13 3rd capacitor 14 AC signal
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−142272（ＪＰ，Ａ) 特開 平１−92664（ＪＰ，Ａ) 特開 平４−370770（ＪＰ，Ａ) 特開 昭63−94168（ＪＰ，Ａ) 特開 平３−62708（ＪＰ，Ａ) 実開 平４−4282（ＪＰ，Ｕ) 実開 昭57−156869（ＪＰ，Ｕ) 実開 昭49−16712（ＪＰ，Ｕ) 実開 昭48−103078（ＪＰ，Ｕ) 特公 昭61−34297（ＪＰ，Ｂ２) ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-142272 (JP, A) JP-A-1-92664 (JP, A) JP-A-4-370770 (JP, A) JP-A-63-142 94168 (JP, A) JP-A-3-62708 (JP, A) JP-A-4-4282 (JP, U) JP-A-57-156869 (JP, U) JP-A-49-16712 (JP, U) 48-03078 (JP, U) JP-B 61-34297 (JP, B2)
Claims (3)
し、第１コンデンサの他端を第１ダイオードのアノード
及びコイルの一端に接続し、第１ダイオードのカソード
を出力端子に接続し、コイルの他端を、入力側が高イン
ピーダンスで出力側が低インピーダンスであるインピー
ダンス変換器の出力端及び第３コンデンサの一端に接続
し、第３コンデンサの他端を接地し、インピーダンス変
換器の入力端に第２ダイオードのアノード及び定電流源
の一端を接続し、第２ダイオードのカソード及び定電流
源の他端を接地し、出力端子と接地間に第１抵抗及び第
２コンデンサを並列に接続したことを特徴とするレベル
検出回路。An input terminal is connected to one end of a first capacitor, the other end of the first capacitor is connected to an anode of a first diode and one end of a coil, and a cathode of the first diode is connected to an output terminal. Is connected to the output terminal of an impedance converter whose input side is high impedance and the output side is low impedance and one end of a third capacitor, the other end of the third capacitor is grounded, and the other end is connected to the input terminal of the impedance converter. 2 The anode of the diode and one end of the constant current source are connected, the cathode of the second diode and the other end of the constant current source are grounded, and the first resistor and the second capacitor are connected in parallel between the output terminal and ground. Characteristic level detection circuit.
構成した請求項１記載のレベル検出回路。2. The level detection circuit according to claim 1, wherein the impedance converter is constituted by an amplifier having a gain of 1.
端を有し負の入力端を出力端に接続し正の入力端を入力
端とした増幅器で構成した請求項２記載のレベル検出回
路。3. An amplifier having a gain of 1 and comprising a positive input terminal and a negative input terminal, the negative input terminal being connected to the output terminal, and the positive input terminal being the input terminal. Level detection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12224094A JP2621798B2 (en) | 1994-06-03 | 1994-06-03 | Level detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12224094A JP2621798B2 (en) | 1994-06-03 | 1994-06-03 | Level detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07333264A JPH07333264A (en) | 1995-12-22 |
| JP2621798B2 true JP2621798B2 (en) | 1997-06-18 |
Family
ID=14831062
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12224094A Expired - Lifetime JP2621798B2 (en) | 1994-06-03 | 1994-06-03 | Level detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2621798B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104345208B (en) * | 2013-07-26 | 2017-02-22 | 北京航天计量测试技术研究所 | Driving circuit for improving balance micro torque calibration instrument accuracy |
-
1994
- 1994-06-03 JP JP12224094A patent/JP2621798B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07333264A (en) | 1995-12-22 |
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