JPS61231616A - Constant current circuit - Google Patents
Constant current circuitInfo
- Publication number
- JPS61231616A JPS61231616A JP7195785A JP7195785A JPS61231616A JP S61231616 A JPS61231616 A JP S61231616A JP 7195785 A JP7195785 A JP 7195785A JP 7195785 A JP7195785 A JP 7195785A JP S61231616 A JPS61231616 A JP S61231616A
- Authority
- JP
- Japan
- Prior art keywords
- current
- circuit
- constant current
- mirror circuit
- collector
- 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
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
- G05F3/26—Current mirrors
- G05F3/265—Current mirrors using bipolar transistors only
Abstract
Description
【発明の詳細な説明】
〔発明の属する技術分野〕
この発明は一定の電流ケ出力する定電流回路の回路構成
に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a circuit configuration of a constant current circuit that outputs a constant current.
この種の定電流回路としては第３図に示す回路構成のも
のが知られている。図において１は回路電源、２は定電
流源、３，４．５はトランジスタで、トランジスタ３．
４はエミ、り面積比がにｍなるカレントミラー回路を構
成しており、トランジスタ５、トランジスタ３．４にペ
ース電流を供給している。As this type of constant current circuit, a circuit configuration shown in FIG. 3 is known. In the figure, 1 is a circuit power supply, 2 is a constant current source, 3, 4.5 are transistors, and transistors 3.
Reference numeral 4 constitutes a current mirror circuit having an emitter-to-area ratio of m, and supplies a pace current to the transistor 5 and the transistor 3.4.
この回路において定電流源２からの電流値を■ｉｎｓト
ランジスタ３ 、４ 、５のコレクタ電流をそれぞれＩ
に３ ＋ ’Ｃ４＋ ■Ｃ５、電流増幅惠をそれぞれ１
１ＦＦ！１ ＋ ）’ＦＥ４ ＋ ”ＦＩ５とすると、
各トランジスタ３゜４．５の電流増幅率は略々等しいか
らｈＰＥ３二ｈＦＥ４” ）ｌＦｇｓ ＝ ｈｙｚとお
き、ｈＦｇ ＞ １ およびｍ＞１とすると次式が成立
する。In this circuit, the current value from the constant current source 2 is set to the collector current of transistors 3, 4, and 5.
3 + 'C4+ ■C5, current amplification 1 each
1FF! 1 + )'FE4 + ``FI5,
Since the current amplification factors of each transistor 3°4.5 are approximately equal, if hPE32hFE4'')lFgs=hyz and hFg>1 and m>1, the following equation holds true.
さらにトランジスタ３．４のエミ、り面積比１：ｍの実
用的範囲においては ｈｙＥ＞ ｍが成立するから（１
）〜（３）式はさらに次式で示される。Furthermore, in a practical range where the emitter and area ratio of transistor 3.4 is 1:m, hyE>m holds true (1
) to (3) are further expressed by the following equations.
ｉｃ’ａζＩｉｎ ・・・・・・・四囲（４）ＩＯ２
嬌ｍ Ｉ ｉ。・・・・・・・・・・・・・・・（５）
Ｉｃｓ ＃ ｆｉｎ ＝−・（６１ｌＰＫ
ここで、この定電流回路の出力電流■ｏ＝■ｃ４を駆動
するのに必要な回路゛電源１の消費電流ＩＯＣは次式で
示される。ic'aζIin ・・・・・・Square (4) IO2
嬌mIi.・・・・・・・・・・・・・・・(5)
Ics # fin =- (61lPK Here, the current consumption IOC of the circuit power supply 1 necessary to drive the output current o = c4 of this constant current circuit is expressed by the following equation.
ＩＣＣ＝＝ Ｉ ｉｌｌ ＋ＩＣ５＃ （１＋ 、、
、 ）”Ｉｉｔ、””””・（７１出力電流Ｉｏ＝ｍＩ
ｊｎを得るための消費電流ＩＯＣとしては、入力電流Ｉ
ｉｎのみであれば理想的であるが（７）式より明らかな
ようにこの回路を用いると消費電流Ｉ。０は兄７・Ｉｉ
ｎだけ増える。とくに低消費化を図りつつ大出力電流を
取りたい用途に対してはエミ、り面積比ｍを大きくする
必要がある。ICC== I ill +IC5# (1+ ,,
, )”Iit,””””・(71 Output current Io=mI
The current consumption IOC for obtaining jn is the input current I
It would be ideal if there was only in, but as is clear from equation (7), if this circuit is used, the current consumption I. 0 is older brother 7.Ii
Increases by n. In particular, for applications where it is desired to obtain a large output current while reducing power consumption, it is necessary to increase the emitter area ratio m.
ところがｍを大きくするとＨ，丁■Ｉｎの値が増大し、
損失が大きくなるという欠点があった。However, when m is increased, the value of H and In increases,
The disadvantage was that losses would be large.
この発明は上述した事情に鑑み、低消費電流化・ を図
ってなお損失を少なく大きな定電流値が得られる、定電
流回路を提供することを目的とする。In view of the above-mentioned circumstances, it is an object of the present invention to provide a constant current circuit that can achieve a large constant current value with less loss while reducing current consumption.
〔発明の要点〕
この発明はカレントミラー回路と、該カレントミラー回
路の入力側に接続した定電流源と、前記カレントミラー
回路に駆動電流を供給するトランジスタを備えた定電流
回路において、前記トランジスタのコレクタを前記カレ
ントミラー回路の出力端に接続することによって、前記
駆動電流を前記カレントミラー回路の出力電流の一部と
なして、前記カレントミラー”回路の回路電源の消費電
流としては略々前記定電流源の電流だけにしようとする
ものである。[Summary of the Invention] The present invention provides a constant current circuit including a current mirror circuit, a constant current source connected to the input side of the current mirror circuit, and a transistor that supplies a driving current to the current mirror circuit. By connecting the collector to the output end of the current mirror circuit, the drive current becomes part of the output current of the current mirror circuit, and the current consumption of the circuit power supply of the current mirror circuit is approximately equal to the above-mentioned constant. This is intended to limit the current to only the current source.
第１図はこの発明の実施例を示すもので、各構成要素は
第３図の従来のものと同様であるが、従来と異なってい
る点はトランジスタ５のコレクタを定電流源２に接伏し
ないで、トランジスタ４のコレクタに接続したことであ
る。このように構成すれば出力端子６から取出される出
力電流■ｏと回路電源１の消費電流Ｉｃｃは次式で示さ
れる。FIG. 1 shows an embodiment of the present invention. Each component is the same as the conventional one shown in FIG. 3, but the difference from the conventional one is that the collector of the transistor 5 is connected to the constant current source 2. Instead, it was connected to the collector of transistor 4. With this configuration, the output current ``o'' taken out from the output terminal 6 and the consumption current Icc of the circuit power supply 1 are expressed by the following equation.
＃ ｎｌ ’ Ｉ ｉ（１四囲曲・・四囲・・・・四囲
曲・四囲曲（８１１ｃｃ＝Ｉｉｎ ・・・叩・曲（
９）ここで従来例の（７）式と前記（９）式を比べれば
明らかなように出力電流Ｉｇ＝ｍ・Ｉｉｎ’＋得るため
に必要・な消費電流Ｉｃｅは従来例に比べて」し・Ｉｉ
ｎ だけ少ない値となる。とくに大きな定電流出力ＩＯ
を得る場合には、トランジスタ３と４のエミ、り面積比
ｍｖ大きくしなければなら゛ないのでその時の消費電流
の低減には効果が大きい。。# nl 'I i (1 4-circle song, 4-circle song, 4-circle song, 4-circle song (811cc=Iin...beat, song (
9) If we compare the formula (7) of the conventional example with the formula (9) above, it is clear that the consumption current Ice required to obtain the output current Ig=m・Iin'+ is smaller than that of the conventional example.・Ii
The value will be smaller by n. Especially large constant current output IO
In order to obtain this, it is necessary to increase the emitter area ratio mv of transistors 3 and 4, which is very effective in reducing current consumption. .
第２図はこの発明の他の実施例を示すもので、第１図に
示す例と異なる点はトランジスタ３と４をエミ、り面積
比１：１のトランジスタ７と８で置き換えるとともに、
エミ、りに抵抗体９とｌ０Ｑｉれぞれ接続したことであ
る。このように電流比をエミ、り面積比で決めていたも
めを抵抗体９゜１０の抵抗値の比で決めることにより、
トランジスタ８０面積を節約することができる。この回
路にぶいてトランジスタ７と８のコレクタ電流をそれぞ
れ■。７ ｅ ＩＯ８、抵抗体９と１０の抵抗値をそれ
ぞれｎ、、 ＊ Ｒａとすれば■ｃ７．Ｉｃ８．■ｃｓ
は次式で褒せる。FIG. 2 shows another embodiment of the invention, which differs from the example shown in FIG. 1 in that transistors 3 and 4 are replaced with transistors 7 and 8 having an area ratio of 1:1, and
The resistor 9 and l0Qi are connected to the emitter and the resistor, respectively. In this way, the current ratio was determined by the emitter and area ratio, but by determining it by the ratio of the resistance values of the resistors 9° and 10,
The area of transistor 80 can be saved. The collector currents of transistors 7 and 8 are applied to this circuit. 7 e If the resistance values of IO8 and resistors 9 and 10 are n, , *Ra, ■c7. Ic8. ■cs
can be expressed by the following formula.
ＩＣ？ ＃Ｉｉｎ ・・聞・・・・・・・・・曲・
・（ｉｏ）次に出゛力電流ｉｏと消費電流Ｉｃｅは、次
式で示される。IC? #Iin...listen...song...
・(io) Next, the output current io and the consumption current Ice are expressed by the following equation.
Ｉｃｃ ” Ｉｉｎ ・・・・・・・・・・・・・
・・・・・・・・（１４）上式の（１３）では（８）式
のエミ、り面積比ｍが、流低減の効果は前例第１図のも
のと全く同一である。Icc” Iin・・・・・・・・・・・・・・・
(14) In the above equation (13), the emitter area ratio m in equation (8) is exactly the same as the flow reduction effect shown in FIG. 1 of the previous example.
この発明ではカレントミラー回路を駆動する駆動電流を
トランジスタを用いて増幅したので高精度のしかも大き
な値の定電流出力が得られ、前記トランジスタのコレク
タを前記カレントミラー回路の出力端子に接続したので
、駆醜電流をカレントミラー回路の出力電流の一部とな
すことができ、カレントミラー回路の回路′１源の消費
電流としては駆動電流分を省くことができるので、カレ
ントミラー回路の入力を作定電流源の電流のみとなり、
回路の低消費電流化を図ることができる。In this invention, since the drive current for driving the current mirror circuit is amplified using a transistor, a constant current output with high precision and a large value can be obtained, and the collector of the transistor is connected to the output terminal of the current mirror circuit. Since the drive current can be made part of the output current of the current mirror circuit, and the drive current can be omitted from the current consumption of the circuit '1 source of the current mirror circuit, the input of the current mirror circuit can be Only the current of the current source becomes
The current consumption of the circuit can be reduced.
第１図はこの発明の実施例を示す電気回路図、第２図は
この発明の他の実施例を示す電気回路図、第３図は従来
の定電流回路図である。
２：定電流源、３ 、４ 、５ 、７ 、８・・・トラ
ンジスタ。FIG. 1 is an electric circuit diagram showing an embodiment of the present invention, FIG. 2 is an electric circuit diagram showing another embodiment of the invention, and FIG. 3 is a conventional constant current circuit diagram. 2: Constant current source, 3, 4, 5, 7, 8...transistor.
Claims (1)
ントミラー回路の入力側に接続した定電流源と、前記カ
レントミラー回路に駆動電流を供給するトランジスタと
で構成された定電流回路において；前記トランジスタの
コレクタを前記カレントミラー回路の出力端に接続した
ことを特徴とする定電流回路。1) In a constant current circuit composed of a current mirror circuit that creates a predetermined current ratio, a constant current source connected to the input side of the current mirror circuit, and a transistor that supplies a drive current to the current mirror circuit; A constant current circuit characterized in that a collector of a transistor is connected to an output end of the current mirror circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7195785A JPS61231616A (en) | 1985-04-05 | 1985-04-05 | Constant current circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7195785A JPS61231616A (en) | 1985-04-05 | 1985-04-05 | Constant current circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61231616A true JPS61231616A (en) | 1986-10-15 |
Family
ID=13475464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7195785A Pending JPS61231616A (en) | 1985-04-05 | 1985-04-05 | Constant current circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61231616A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100694466B1 (en) * | 2001-12-27 | 2007-03-12 | 매그나칩 반도체 유한회사 | Bias circuit for compensating for current |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4854460A (en) * | 1971-11-11 | 1973-07-31 |
-
1985
- 1985-04-05 JP JP7195785A patent/JPS61231616A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4854460A (en) * | 1971-11-11 | 1973-07-31 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100694466B1 (en) * | 2001-12-27 | 2007-03-12 | 매그나칩 반도체 유한회사 | Bias circuit for compensating for current |
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