JP2860670B2 - Amplifier current detection circuit - Google Patents
Amplifier current detection circuitInfo
- Publication number
- JP2860670B2 JP2860670B2 JP1237256A JP23725689A JP2860670B2 JP 2860670 B2 JP2860670 B2 JP 2860670B2 JP 1237256 A JP1237256 A JP 1237256A JP 23725689 A JP23725689 A JP 23725689A JP 2860670 B2 JP2860670 B2 JP 2860670B2
- Authority
- JP
- Japan
- Prior art keywords
- resistor
- operational amplifier
- output
- terminal
- current
- 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
- Inverter Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
- Control Of Ac Motors In General (AREA)
Description
【発明の詳細な説明】 （１）発明の目的 ［産業上の利用分野］ 本発明は増幅器の電流検出回路に係り、特にベースド
ライバ回路により駆動される出力段トランジスタ回路の
出力電流を検出する構成に関するものである。DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention [Industrial Application Field] The present invention relates to a current detection circuit of an amplifier, and particularly to a configuration for detecting an output current of an output stage transistor circuit driven by a base driver circuit. It is about.
［従来の技術］ 第２図は従来より実施されている電動機制御装置の構
成を示す回路図で、１は３相の商用電源、２は主開閉
器、３は主整流器、４は平滑コンデンサ、５は出力段ト
ランジスタ、６はベースドライバー回路、７は電動機、
８はベースドライバー回路の電源を得る整流器、９はベ
ースドライバー回路の信号入力端子、10は電流検出抵
抗、11はオペアンプ、12,13,14は抵抗、15はオペアンプ
の出力端子である。[Prior Art] FIG. 2 is a circuit diagram showing a configuration of a motor control device which has been conventionally implemented. 1 is a three-phase commercial power supply, 2 is a main switch, 3 is a main rectifier, 4 is a smoothing capacitor, 5 is an output transistor, 6 is a base driver circuit, 7 is a motor,
Reference numeral 8 denotes a rectifier for obtaining the power of the base driver circuit, 9 denotes a signal input terminal of the base driver circuit, 10 denotes a current detection resistor, 11 denotes operational amplifiers, 12, 13, and 14 resistors, and 15 denotes an operational amplifier output terminal.
図示の回路は、３相の商用電源１を主開閉器２を介し
て主整流器３に導き整流して平滑コンデンサ４で平滑に
した直流を、出力段トランジスタ５供給し、前記出力段
トランジスタ５の出力を電動機７に供給する主回路と、
出力段トランジスタ５を駆動するベーイドライバー回路
６と、該ベースドライバー回路６を動作させる電源８と
により構成される副回路とがあり、入力端子９より入力
した制御信号に従い、複数の出力段トランジスタ５のベ
ースに順次電流を流し、出力段トランジスタ５の出力で
電動機７に電流を流し、電動機７を回転駆動させるもの
である。The circuit shown in the figure supplies the output stage transistor 5 with a direct current which is obtained by directing the three-phase commercial power source 1 to the main rectifier 3 via the main switch 2 and rectifying the rectified and smoothed by the smoothing capacitor 4 to the output stage transistor 5. A main circuit for supplying an output to the motor 7,
There is a sub-circuit comprising a bay driver circuit 6 for driving the output stage transistor 5 and a power supply 8 for operating the base driver circuit 6, and a plurality of output stage transistors are provided in accordance with a control signal inputted from an input terminal 9. 5, a current is sequentially supplied to the base of the motor 5, and an electric current is supplied to the motor 7 by the output of the output stage transistor 5, thereby driving the motor 7 to rotate.
更に図示の回路においては電動機７を高精度に制御す
るため、出力段トランジスタ５の（−）側端子と主整流
器３の（−）側端子の間に電流検出抵抗10を介挿し、該
電流検出抵抗10の両端を抵抗12及び14を介してオペアン
プ11の両入力端子に接続し、該オペアンプ11の出力端子
15より出力段トランジスタの電流を検出し、（図示され
ていない）制御装置の信号処理回路に帰還するように構
成されている。Further, in the circuit shown in the figure, in order to control the motor 7 with high accuracy, a current detecting resistor 10 is inserted between the (-) terminal of the output transistor 5 and the (-) terminal of the main rectifier 3 to detect the current. Both ends of the resistor 10 are connected to both input terminals of the operational amplifier 11 via the resistors 12 and 14, and the output terminal of the operational amplifier 11 is connected.
It is configured so that the current of the output stage transistor is detected from 15 and fed back to the signal processing circuit of the control device (not shown).
図示の回路においては電流検出抵抗10の電圧降下を高
増幅率のオペアンプ11で増幅し電流を検出する構成であ
るから、電流検出抵抗10の抵抗値は極めて小さくてよ
く、其の結果電流検出抵抗10の中の電圧降下は極めて小
さくなり損失を減少させることができる。In the illustrated circuit, the voltage drop of the current detection resistor 10 is amplified by the operational amplifier 11 having a high amplification factor to detect the current, so that the resistance value of the current detection resistor 10 may be extremely small. The voltage drop in 10 can be very small and losses can be reduced.
［発明が解決しようとする課題］ ところが第２図に示した従来技術による制御回路にお
いては、出力段トランジスタ５の（−）側端子が接地さ
れており、オペアンプ11の（＋）側入力端子が接地され
ているから、出力段トランジスタ５の電流が流れると、
電流検出抵抗10の電圧降下により出力段トランジスタ５
の（−）側端子とオペアンプ11の（＋）側端子の電位が
変動し、正確な電流値が検出できないという問題があっ
た。[Problems to be Solved by the Invention] However, in the control circuit according to the prior art shown in FIG. 2, the (-) terminal of the output stage transistor 5 is grounded, and the (+) input terminal of the operational amplifier 11 is Since it is grounded, when the current of the output stage transistor 5 flows,
The output stage transistor 5 is generated by the voltage drop of the current detection resistor 10.
The potential of the (−) side terminal of the operational amplifier 11 and the potential of the (+) side terminal of the operational amplifier 11 fluctuate, and an accurate current value cannot be detected.
本発明は上記のような従来技術における問題を解決
し、出力段トランジスタの電流によりオペアンプの接地
電位が変動せず正確な電流の検出ができる電流検出回路
を得るにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to provide a current detection circuit capable of accurately detecting a current without changing a ground potential of an operational amplifier due to a current of an output transistor.
（２）発明の構成 ［課題を解決するための手段］ 本発明においては電流検出抵抗の両端を抵抗を介して
オペアンプの両入力端子に接続すると共に、ベースドラ
イバー回路を動作させる電源の出力端子の両端に抵抗と
ツエナーダイオードを直列に接続し、前記ツエナーダイ
オードの（＋）側端子を抵抗を介して前記オペアンプの
（＋）側端子に接続し、オペアンプの出力端子と、前記
ツエナーダイオードの（＋）側端子との間に電流に比例
した電圧を得る構成により達成する。(2) Configuration of the Invention [Means for Solving the Problems] In the present invention, both ends of a current detection resistor are connected to both input terminals of an operational amplifier via resistors, and an output terminal of a power supply for operating a base driver circuit is connected. A resistor and a Zener diode are connected in series at both ends, a (+) side terminal of the Zener diode is connected to a (+) side terminal of the operational amplifier via a resistor, and an output terminal of the operational amplifier and a (+) of the Zener diode are connected. This is achieved by a configuration that obtains a voltage proportional to the current between the side terminals.
［作用］ オペアンプの（＋）側端子の電位がツエナーダイオー
ドの電圧で固定され、電流検出抵抗の電圧降下を差動増
幅する構成となっているので正確な電流検出をすること
ができる。[Operation] The potential of the (+) side terminal of the operational amplifier is fixed by the voltage of the Zener diode, and the voltage drop of the current detection resistor is differentially amplified, so that accurate current detection can be performed.
［実施例］ 第１図は本発明を実施した電動機制御装置の構成を示
す回路図で、第２図に示した従来技術と同じ構成の部分
は同じ符号を付けて説明を省略する。[Embodiment] FIG. 1 is a circuit diagram showing a configuration of a motor control device embodying the present invention. The same components as those of the prior art shown in FIG.
本発明においては、電流検出抵抗10の出力段トランジ
スタ５の（−）側端子に接続された側をオペアンプ11の
（＋）側端子に、主整流器３の（−）側端子に接続され
た側をオペアンプ11の（−）側端子に、夫々同じ抵抗1
2,14を介して接続し、ベースドライバー回路６を動作さ
せる整流器８の出力端子に抵抗17とツエナーダイオード
18とを直列に接続し、ツエナーダイオード18の（＋）側
端子を抵抗16を介してオペアンプ11の（＋）側端子に接
続し、オペアンプ11の出力端子と前記ツエナーダイオー
ド18の（＋）側端子より電流に比例した出力電圧を得る
構成で、抵抗13はオペアンプ11の帰還率を定める帰還抵
抗である。In the present invention, the side of the current detection resistor 10 connected to the (−) side terminal of the output stage transistor 5 is connected to the (+) side terminal of the operational amplifier 11, and the side connected to the (−) side terminal of the main rectifier 3. To the (−) side terminal of the operational amplifier 11
The resistor 17 and the Zener diode are connected to the output terminal of the rectifier 8 which is connected through
18 is connected in series, the (+) side terminal of the Zener diode 18 is connected to the (+) side terminal of the operational amplifier 11 via the resistor 16, and the output terminal of the operational amplifier 11 and the (+) side of the Zener diode 18 are connected. The resistor 13 is a feedback resistor that determines the feedback ratio of the operational amplifier 11 in a configuration that obtains an output voltage proportional to the current from the terminal.
図示の電流検出回路においては、電流検出抵抗10の電
圧降下を増幅するオペアンプ11の（＋）側電位をツエナ
ーダイオード18で固定し、オペアンプ11の両入力端子に
接続した入力抵抗12,14を同じ値とし、帰還抵抗13と接
地抵抗16の値を調節してオペアンプ11を差動増幅器とし
て動作させる構成としてあるのでオペアンプ11の（＋）
側端子の電位が出力段トランジスタ５の電流により変動
せず、安定な検出電流に比例する出力電圧を得ることが
できる。In the illustrated current detection circuit, the (+) side potential of the operational amplifier 11 for amplifying the voltage drop of the current detection resistor 10 is fixed by a Zener diode 18, and the input resistors 12 and 14 connected to both input terminals of the operational amplifier 11 are the same. And the value of the feedback resistor 13 and the ground resistor 16 are adjusted to operate the operational amplifier 11 as a differential amplifier.
The potential of the side terminal does not fluctuate due to the current of the output stage transistor 5, and a stable output voltage proportional to the detected current can be obtained.
［発明の効果］ 本発明になる増幅器の電流検出回路は前記のような構
成であるからオペアンプの（＋）側端子の電位が固定さ
れ、差動増幅するようになっているので出力段トランジ
スタの電流を正確に検出できる効果がある。[Effect of the Invention] Since the current detection circuit of the amplifier according to the present invention has the above-described configuration, the potential of the (+) side terminal of the operational amplifier is fixed and the differential amplification is performed. This has the effect of accurately detecting the current.
第１図は本発明の構成を示す制御装置の回路図、第２図
は従来より実施されている制御装置の構成を示す回路図
である。 符号の説明 １…３相の商用電源,2…主開閉器,3…主整流器,4…平滑
コンデンサ,5…出力段トランジスタ,6…ベースドライバ
ー回路,7…電動機,8…ベースドライバー回路を動作させ
る整流器,9…制御信号の入力端子,10…電流検出抵抗,11
…オペアンプ,12,13,14,16,17…抵抗,15…オペアンプの
出力端子,18…ツエナーダイオード。FIG. 1 is a circuit diagram of a control device showing a configuration of the present invention, and FIG. 2 is a circuit diagram showing a configuration of a conventionally implemented control device. DESCRIPTION OF SYMBOLS 1 ... three-phase commercial power supply, 2 ... main switch, 3 ... main rectifier, 4 ... smoothing capacitor, 5 ... output stage transistor, 6 ... base driver circuit, 7 ... electric motor, 8 ... base driver circuit Rectifier, 9 ... input terminal of control signal, 10 ... current detection resistor, 11
... operational amplifiers, 12, 13, 14, 16, 17 ... resistors, 15 ... output terminals of operational amplifiers, 18 ... Zener diodes.
フロントページの続き (56)参考文献 特開 昭60−131093（ＪＰ，Ａ) 特開 昭62−100188（ＪＰ，Ａ) 特開 昭64−34192（ＪＰ，Ａ) 特開 平１−278290（ＪＰ，Ａ) 特開 昭56−87866（ＪＰ，Ａ) 特開 昭56−74660（ＪＰ，Ａ) 実開 昭59−109299（ＪＰ，Ｕ) 実開 昭63−158472（ＪＰ，Ｕ) 実開 昭64−6152（ＪＰ，Ｕ) 実開 昭61−67570（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01R 19/00 - 19/32 H02M 7/48 - 7/5395 H02P 7/288 H02P 7/36 - 7/66Continuation of the front page (56) References JP-A-60-131093 (JP, A) JP-A-62-100188 (JP, A) JP-A-64-34192 (JP, A) JP-A-1-278290 (JP) JP-A-56-87866 (JP, A) JP-A-56-74660 (JP, A) JP-A-59-109299 (JP, U) JP-A-63-158472 (JP, U) JP-A-63-158472 (JP, U) 64-6152 (JP, U) Fully open Sho 61-67570 (JP, U) (58) Fields investigated (Int. Cl. 6 , DB name) G01R 19/00-19/32 H02M 7/48-7 / 5395 H02P 7/288 H02P 7/36-7/66
Claims (1)
を駆動する電動機駆動用増幅器の出力電流を検出する回
路で、出力段トランジスタの接地側端子と電源の（−）
端子の間に挿入した電流検出抵抗の電圧をオペアンプで
増幅して電流を検出する構成のものにおいて、前記電流
検出抵抗の両端を抵抗を介してオペアンプの両入力端子
に接続し、電流検出抵抗の電源の（−）端子に接続され
た側のオペアンプの入力端子と出力端子の間に帰還抵抗
を接続し、前記ベースドライバ回路を動作させる電源回
路の（＋）と（−）の端子間に抵抗とツエナーダイオー
ドを接続し、抵抗とツエナーダイオードの接続点と前記
オペアンプの他の入力端子の間に前記帰還抵抗と同じ値
の抵抗を接続し、オペアンプの出力端子と、前記抵抗と
ツエナーダイオードとの接続点より、前記出力段トラン
ジスタの出力電流に比例した電圧を得る構成を特徴とす
る増幅器の電流検出回路。1. A circuit for detecting an output current of a motor drive amplifier for driving an output transistor in a base drive circuit, wherein a ground terminal of the output transistor and a power supply (-)
In a configuration in which the voltage of the current detection resistor inserted between the terminals is amplified by an operational amplifier to detect current, both ends of the current detection resistor are connected to both input terminals of the operational amplifier via the resistor, and A feedback resistor is connected between the input terminal and the output terminal of the operational amplifier on the side connected to the (-) terminal of the power supply, and a resistor is provided between the (+) and (-) terminals of the power supply circuit for operating the base driver circuit. And a Zener diode, and a resistor having the same value as the feedback resistor is connected between a connection point of the resistor and the Zener diode and another input terminal of the operational amplifier, and an output terminal of the operational amplifier and the resistor and the Zener diode are connected. A current detection circuit for an amplifier, wherein a voltage proportional to an output current of the output stage transistor is obtained from a connection point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1237256A JP2860670B2 (en) | 1989-09-14 | 1989-09-14 | Amplifier current detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1237256A JP2860670B2 (en) | 1989-09-14 | 1989-09-14 | Amplifier current detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03100469A JPH03100469A (en) | 1991-04-25 |
| JP2860670B2 true JP2860670B2 (en) | 1999-02-24 |
Family
ID=17012716
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1237256A Expired - Lifetime JP2860670B2 (en) | 1989-09-14 | 1989-09-14 | Amplifier current detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2860670B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997037855A1 (en) * | 1996-04-10 | 1997-10-16 | Sony Corporation | Display system, display method, ink ribbon, printer and image formation apparatus |
| JP4613523B2 (en) * | 2004-06-16 | 2011-01-19 | ダイキン工業株式会社 | Current measuring device |
-
1989
- 1989-09-14 JP JP1237256A patent/JP2860670B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03100469A (en) | 1991-04-25 |
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