JPS6129920A - Constant current source - Google Patents

Constant current source

Info

Publication number
JPS6129920A
JPS6129920A JP15094884A JP15094884A JPS6129920A JP S6129920 A JPS6129920 A JP S6129920A JP 15094884 A JP15094884 A JP 15094884A JP 15094884 A JP15094884 A JP 15094884A JP S6129920 A JPS6129920 A JP S6129920A
Authority
JP
Japan
Prior art keywords
voltage
base
input
proportional
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.)
Pending
Application number
JP15094884A
Other languages
Japanese (ja)
Inventor
Manabu Iwasaki
学 岩崎
Yoshihiro Matsumoto
吉弘 松本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fuji Electric Co Ltd
Original Assignee
Fuji Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fuji Electric Co Ltd filed Critical Fuji Electric Co Ltd
Priority to JP15094884A priority Critical patent/JPS6129920A/en
Publication of JPS6129920A publication Critical patent/JPS6129920A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
    • G05F3/02—Regulating voltage or current
    • G05F3/08—Regulating voltage or current wherein the variable is dc
    • G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
    • G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
    • G05F3/20—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
    • G05F3/22—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations wherein the transistors are of the bipolar type only
    • G05F3/222—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations wherein the transistors are of the bipolar type only with compensation for device parameters, e.g. Early effect, gain, manufacturing process, or external variations, e.g. temperature, loading, supply voltage

Abstract

PURPOSE:To obtain an inexpensive constant current circuit extracting an output current proportional to a set voltage by inserting a diode whose forward voltage drop is equal to a base-emitter voltage of a transistor (TR) between a base of the TR and an earth. CONSTITUTION:An output voltage Vout of an operational amplifier 4 is proportional to an input set voltage Vin and the input voltage Vout of a TR11 and an input current IE are not accurately proportional because the current amplification factor hBE characteristic gives the effect. Thus, two diodes 13 are connected in series with a base of the TR11 having the large hBE and the diodes are earthed and the base is given with a negative potential by a resitor 12 connected to a negative power supply -VCC, then it is the same as the case with neglecting a base-emitter voltage VBE apparently because of the forward voltage drop VD of a diode 13. Thus, the voltage Vin versus output current IC have a linearity and an output current proportional to the input setting voltage is obtained.

Description

【発明の詳細な説明】 ［発明の属する技術分野１ この発明は定電流源回路に関する。[Detailed description of the invention] [Technical field to which the invention pertains 1 The present invention relates to a constant current source circuit.

Ｉ従来技術とその問題点ま たとえば入力設定電圧に比例した周波数を出力するＶ／
Ｆフンバータにおいて、従来、その回路を構成するのに
専用の回路を用いる方法があるが高価である。そこで、
安価で簡単に周波数を出力させる回路としてタイマＩＣ
を用いた第６図に示すような発振回路が知られている。I Conventional technology and its problems For example, a V/V that outputs a frequency proportional to the input setting voltage.
Conventionally, there is a method of using a dedicated circuit to configure the F-fumverter, but this method is expensive. Therefore,
Timer IC as a cheap and easy circuit to output frequency
An oscillation circuit as shown in FIG. 6 using the oscillation circuit is known.

ると、タイマＩＣ２１にその入力電圧が印加されると共
に、電流ｉにより抵抗２２を介してコンデンサ２３が充
電される６コンデンサ２３の充電々圧が一定になると抵
抗２４を介してタイマＩＣ２１のピン（７）と（１）間
にコンデンサ２３の電荷が放電され、この時タイマｊｃ
２１の出力端子２４にパルスが出力される。このため発
振周期は、コンデンサ２３の充電時間に依存していて、
抵抗２２とコンデンサ２３とのＲＣ時定数で決まる周波
数が出力される。Then, the input voltage is applied to the timer IC 21, and the capacitor 23 is charged by the current i via the resistor 22. When the charging voltage of the capacitor 23 becomes constant, the input voltage is applied to the timer IC 21 via the resistor 24 ( The charge in the capacitor 23 is discharged between 7) and (1), and at this time the timer jc
A pulse is output to the output terminal 24 of 21. Therefore, the oscillation period depends on the charging time of the capacitor 23,
A frequency determined by the RC time constant of the resistor 22 and capacitor 23 is output.

ところが第７図で示すようにコンデンサ２３の充電々圧
Ｖｃと充電時間ｔとは比例しないため、この発振回路に
電圧が入力されてもその電圧に比例した周波数を出力す
ることは出来ない。However, as shown in FIG. 7, the charging voltage Vc of the capacitor 23 and the charging time t are not proportional, so even if a voltage is input to this oscillation circuit, it cannot output a frequency proportional to the voltage.

一方、第６図の発振回路の入力端子２０に定電流源を接
地した場合、第８図で示すようにコンデンサ２３の充電
々圧Ｖｃと充電時開ｔとは比例関係にあるため、この発
振回路は入力電流に比例した周波数を出力する。しかし
、このためには入力が必要となり、従来この定電流源回
路は高価であった。On the other hand, if a constant current source is grounded to the input terminal 20 of the oscillation circuit shown in FIG. 6, the oscillation The circuit outputs a frequency proportional to the input current. However, this requires an input, and conventional constant current source circuits have been expensive.

［発明の目的］ この発明は上述の事情を考慮してなされたものであって
、簡単な構成で安価な定電流源回路を提供することを目
的とするものである。[Object of the Invention] The present invention has been made in consideration of the above-mentioned circumstances, and it is an object of the present invention to provide a constant current source circuit that has a simple configuration and is inexpensive.

［発明の構成］ この発明の定電流源回路は演算増幅器とベース接地で用
いられたＬＩＦＥの天外いトランジスタで構成され、こ
のトランジスタのベースと接地との間に順方向電圧降下
かこのトランジスタのＶＢＥ電圧と等しいダイオードを
挿入してなり、設定電圧に対して直線的に出力電流を比
例させることができる。[Structure of the Invention] The constant current source circuit of the present invention is composed of an operational amplifier and a LIFE transistor with a common base. By inserting a diode equal to the voltage, the output current can be made linearly proportional to the set voltage.

第１図は本発明の実施例を示す回路図で以下この回路図
により説明する。FIG. 1 is a circuit diagram showing an embodiment of the present invention, and the following description will be made with reference to this circuit diagram.

１は電圧ＶｉｎがＯＶよりマイナス１０■まで可変の設
定電圧源でこの設定電圧源のマイナス側端子は入力抵抗
３を介して演算増幅器４の反転入力端子５に接続される
。演算増幅器４の非反転入力端子６は抵抗７を介して接
地される。Reference numeral 1 denotes a set voltage source whose voltage Vin is variable from OV to minus 10 cm, and the negative terminal of this set voltage source is connected to an inverting input terminal 5 of an operational amplifier 4 via an input resistor 3. A non-inverting input terminal 6 of the operational amplifier 4 is grounded via a resistor 7.

演算増幅器４の出力端子８は帰還抵抗９を介して反転入
力端子５に接続されると共にこの出力端子８は半固定抵
抗１０を介してトランジスタ１１のエミッタに接続され
る。トランジスタ６のべ一入には、他方をマイナス電源
（−入Ｉ’ｃｃ）に接続した抵抗１２と２個直列接続し
たダイオード１３のアノード側とが接続され、ダイオー
ド１３のカソード側は接地される。トランジスタ１１の
コレクタは出力端子１４を介して前述のタイマＩＣ２１
のピン（６）に接続される。The output terminal 8 of the operational amplifier 4 is connected to the inverting input terminal 5 via a feedback resistor 9, and this output terminal 8 is connected via a semi-fixed resistor 10 to the emitter of a transistor 11. A resistor 12 whose other end is connected to a negative power supply (-input I'cc) and an anode side of two diodes 13 connected in series are connected to one terminal of the transistor 6, and the cathode side of the diode 13 is grounded. . The collector of the transistor 11 is connected to the above-mentioned timer IC 21 via the output terminal 14.
is connected to pin (6) of

上記のように構成した回路は次のように動作する。設定
電圧は演算増幅器４の反転入力端子５に印加され、演算
増幅器４の出力端子８には上記設定電圧に対応した電圧
が出力され、トランジスタ１１のエミッタに印加される
。The circuit configured as described above operates as follows. The set voltage is applied to the inverting input terminal 5 of the operational amplifier 4, and a voltage corresponding to the set voltage is outputted to the output terminal 8 of the operational amplifier 4 and applied to the emitter of the transistor 11.

そしてＦランラスタ１１のコレクタには上記設定電圧に
対応した電流が出力される。A current corresponding to the set voltage is output to the collector of the F run raster 11.

以下、回路の動作について詳述を判りやすくするために
、トランジスタ１１のべ一又を直接接地した第２図につ
いて説明する。Hereinafter, in order to make the detailed description of the operation of the circuit easier to understand, a description will be given of FIG. 2 in which the base of the transistor 11 is directly grounded.

演算増幅器４の入力電圧即ち設定電圧をＶｉｎ。The input voltage, that is, the set voltage of the operational amplifier 4 is Vin.

出力電圧をＶｏｕｔとし、入力抵抗３と帰還抵抗９の抵
抗値をそれぞれＲ３，Ｒ９とするとＶｏｕｔ　＝−Ｒ９
／Ｒ，・Ｖｉｎとなり平衡が保たれる。この時、トラン
ジスタ１１に流れるエミッタ電流ＩＥは、トランジスタ
１１のベース・エミッタ間電圧■ＢＥを無視すれば＼’
ｏｕｔの値を半固定抵抗１０の抵抗値（Ｒ，、とする）
で割った値となる。即ち、Ｉ　Ｅ＝Ｖｏｕｔ　／　Ｒ＋
ｏとなる。そして、トランジスタ１１の電流増幅率をｌ
＋　Ｆ　Ｅとし、コレクタ電流を■ｃ、ベース電流をＩ
Ｂとすると、　ＩＩ　ｐ　Ｅ　＝Ｉ　ｃ　／　Ｉ　Ｂ又
はｌＩＣ１＝ｌ　ＩＥ＋−１１Ｂ＋の関係があるため、
トランジスタ１１がダーリントントランジスタのように
ｈＦＥが非常に太きけれＩ　Ｃ＝ｉ−Ｉ　、となり負荷
に流れ込む。以上の関係を第３図、第４図、第５図に示
す。When the output voltage is Vout and the resistance values of input resistor 3 and feedback resistor 9 are R3 and R9, respectively, Vout = -R9
/R,·Vin, and equilibrium is maintained. At this time, the emitter current IE flowing through the transistor 11 is \' if the base-emitter voltage ■BE of the transistor 11 is ignored.
The value of out is the resistance value of semi-fixed resistor 10 (R,,)
The value divided by That is, IE=Vout/R+
It becomes o. Then, the current amplification factor of the transistor 11 is set to l
+ F E, the collector current is c, and the base current is I
If B, then there is a relationship of II p E = I c / I B or lIC1 = l IE+-11B+, so
If the transistor 11 is a Darlington transistor, hFE becomes very thick, I C =i-I, and the current flows into the load. The above relationships are shown in FIGS. 3, 4, and 5.

演算増幅器４の出力電圧は入力電圧に比例するが（第３
図の通り）、トランジスタ１１の入力電圧トランジスタ
１１の■ＢＥ特性が影響を与えるため第４図のグラフで
示す破線のように、正確に比例しない。The output voltage of the operational amplifier 4 is proportional to the input voltage (the third
As shown in the figure), the input voltage of the transistor 11 is influenced by the BE characteristic of the transistor 11, so it is not accurately proportional as shown by the broken line in the graph of FIG.

従って、入力設定電圧Ｖｉｎと、トランジスタ１１の出
力電流ＩＣとは第５図のグラフで示す破線ののようにな
り比例しなくなる。Therefore, the input setting voltage Vin and the output current IC of the transistor 11 become as shown by the broken line shown in the graph of FIG. 5, and are no longer proportional to each other.

これを防止するだめの補正回路として第１図の回路図の
如く１１のベースにダイオードを２個直列に挿入し、又
一方をマイナス電源（−Ｖｃｃ）に接続した抵抗１２で
もってトランジスタ１１のベースを負電位にしておくと
、ダイオード１３の順方向電圧降下■ゎのため、ＶＢＥ
の影響をなくすことが出来、見かけ上＼’ＢＥを無視し
た場合と同じようになる。第４図、第５図の実線で示す
ようにＶｏｕｔ対ＩＥ、又Ｖｉｎ対ＩＣは直線性を有し
、入力設定電圧Ｖｉｎに比例した出力電流■。が得られ
る。従ってタイマＩＣ２１からは入力設定電圧に直線的
に比例した周波数のパルスが得られる。As a correction circuit to prevent this, two diodes are inserted in series at the base of transistor 11 as shown in the circuit diagram in Fig. When VBE is set to a negative potential, VBE decreases due to the forward voltage drop of the diode 13.
The effect of \'BE can be eliminated, and the appearance is the same as if \'BE was ignored. As shown by the solid lines in FIGS. 4 and 5, Vout vs. IE and Vin vs. IC have linearity, and the output current is proportional to the input setting voltage Vin. is obtained. Therefore, a pulse with a frequency linearly proportional to the input setting voltage is obtained from the timer IC 21.

［発明の効果１ を出力する定電流源回路が演算増幅器と、トランジスタ
等の少ない部品で構成されるので回路が簡単となりかつ
安価に製作出来る。又、タイマＩＣを利用した発振器と
組合せれば、入力設定電圧に比例した周波数を出力する
Ｖ／Ｆコンバータを安価に作ることが出来る。[Effect of the Invention 1] Since the constant current source circuit that outputs the output is composed of an operational amplifier and a small number of components such as transistors, the circuit becomes simple and can be manufactured at low cost. Furthermore, by combining it with an oscillator using a timer IC, a V/F converter that outputs a frequency proportional to the input set voltage can be manufactured at low cost.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はこの発明の一実施例を示す回路図、第２図は第
１図の回路を簡略化した回路図、第３図は演算増幅器４
の入力電圧対出力電圧の関係を示すグラフ、第４図は演
算増幅器４の出力電圧対トランジスタ１１のエミッタ電
流の関係を示すグラフ、第５図は演算増幅器の入力電圧
対トランジスタ１１のフレフタ出力電流の関係を示すグ
ラフ、第６図は、発振回路の一例を示す回路図、第７図
はコンデンサの充電々圧と充電時間の関係を示すグラフ
、第８図は定電流源を用いた場合のコンデンサ充電々圧
と充電時間の関係を示すグラフである。 １・・・入力設定電圧源、４・・・演算増幅器、１０・
・・半固定抵抗、１１・・・ダーリントントランンスタ
、１３・・・ダイオード。 特許出願人　　富士電機製造株式会社 代理　人　弁理士　青　山　葆外２名 第１図 下 第２図 第３図 第４図 第５図 ＯＶｉｎFIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a simplified circuit diagram of the circuit in FIG. 1, and FIG. 3 is an operational amplifier 4.
4 is a graph showing the relationship between the output voltage of the operational amplifier 4 and the emitter current of the transistor 11. FIG. Figure 6 is a circuit diagram showing an example of an oscillation circuit, Figure 7 is a graph showing the relationship between capacitor charging voltage and charging time, and Figure 8 is a diagram showing the relationship between capacitor charging voltage and charging time. It is a graph showing the relationship between capacitor charging pressure and charging time. 1... Input setting voltage source, 4... Operational amplifier, 10.
...Semi-fixed resistor, 11...Darlington transformer, 13...diode. Patent applicant Fuji Electric Manufacturing Co., Ltd. Agent Patent attorney Aoyama Sogai 2 people Figure 1 Lower Figure 2 Figure 3 Figure 4 Figure 5 OVin

Claims (1)

【特許請求の範囲】[Claims] （１）演算増幅器とベース接地で用いられたｈ＿Ｆ＿Ｅ
の大きいトランジスタで構成され、このトランジスタの
ベースと接地との間に順方向電圧降下がこのトランジス
タのＶ＿Ｂ＿Ｅ電圧と等しいダイオードを挿入したこと
を特徴とする定電流源回路。(1) h_F_E used in operational amplifier and common base
1. A constant current source circuit characterized in that a diode is inserted between the base of the transistor and ground, the forward voltage drop of which is equal to the V_B_E voltage of the transistor.
JP15094884A 1984-07-19 1984-07-19 Constant current source Pending JPS6129920A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15094884A JPS6129920A (en) 1984-07-19 1984-07-19 Constant current source

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15094884A JPS6129920A (en) 1984-07-19 1984-07-19 Constant current source

Publications (1)

Publication Number Publication Date
JPS6129920A true JPS6129920A (en) 1986-02-12

Family

ID=15507914

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15094884A Pending JPS6129920A (en) 1984-07-19 1984-07-19 Constant current source

Country Status (1)

Country Link
JP (1) JPS6129920A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5437131A (en) * 1987-09-29 1995-08-01 Hashimoto Forming Industry Co., Ltd. Window molding members and method of manufacturing same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5437131A (en) * 1987-09-29 1995-08-01 Hashimoto Forming Industry Co., Ltd. Window molding members and method of manufacturing same

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