JPH0475533B2 - - Google Patents
Info
- Publication number
- JPH0475533B2 JPH0475533B2 JP58143544A JP14354483A JPH0475533B2 JP H0475533 B2 JPH0475533 B2 JP H0475533B2 JP 58143544 A JP58143544 A JP 58143544A JP 14354483 A JP14354483 A JP 14354483A JP H0475533 B2 JPH0475533 B2 JP H0475533B2
- Authority
- JP
- Japan
- Prior art keywords
- current
- circuit
- output
- resistor
- voltage
- 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
- 230000000630 rising effect Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
- G05F1/569—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for protection
- G05F1/573—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for protection with overcurrent detector
- G05F1/5735—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for protection with overcurrent detector with foldback current limiting
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Continuous-Control Power Sources That Use Transistors (AREA)
Description
【発明の詳細な説明】
この発明は、例えばIC等を使用した回路の出
力側端子の短絡事故等による過電流に対する保護
を行なう電流リミツタ装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a current limiter device that protects an output terminal of a circuit using an IC or the like from overcurrent caused by a short circuit accident.
IC等を含む回路によつて構成される例えば電
子的制御ユニツトから、外部の制御対象となる装
置に対して5V電源を供給するような場合、上記
ユニツトに対して設けられた出力端子から外部装
置に対する駆動信号を取り出す。この場合、例え
ばこの出力回路に用いられる導線にかみ込み等が
発生し、短絡のような障害が発生した場合、上記
ユニツト内のパワートランジスタを破壊する事故
を生ずる。したがつて、このパワートランジスタ
を保護するために、このトランジスタに流れる電
流を検出し、リミツタをかけることが行なわれて
いる。 For example, when an electronic control unit consisting of a circuit including an IC etc. supplies 5V power to an external device to be controlled, an output terminal provided for the unit is connected to the external device. Extract the drive signal for. In this case, for example, if the conductive wire used in the output circuit gets caught and a fault such as a short circuit occurs, an accident may occur that destroys the power transistor in the unit. Therefore, in order to protect this power transistor, the current flowing through this transistor is detected and a limiter is applied.
このような電流リミツタ装置としては、従来に
おいて例えば次のようなものが考えられている。
すなわち、回路に流れる電流値を特定される基準
電流値と対比し、短絡電流が流れる状態でこれを
検出して上記回路を開放するように制御するもの
である。しかし、このような構成の装置では、短
絡時においてのみ効果的な保護動作が実行される
ように設定しているものであるため、過渡的にも
短絡時に非常に大きな電流が流れる状態となる。
また、このような点をさけるために上記基準電流
値を制限した場合には、負荷回路において必要な
充分な電流を取り出すことがでなくなつて電流が
不足し、電子的制御ユニツトによる負荷制御を、
広範囲にわたつて実行させることが困難となる。 Conventionally, the following types of current limiter devices have been considered, for example.
That is, the current value flowing through the circuit is compared with a specified reference current value, and when a short circuit current is flowing, this is detected and the circuit is controlled to be opened. However, in a device having such a configuration, an effective protection operation is performed only in the event of a short circuit, so that a very large current flows even transiently in the event of a short circuit.
In addition, if the above reference current value is limited to avoid such a problem, the load circuit will not be able to take out the sufficient current required, resulting in a current shortage and the load control by the electronic control unit. ,
This makes it difficult to implement it over a wide range of areas.
この発明は上記のような点に鑑みされたもの
で、例えば電子的制御ユニツトから出力電流をり
出すパワートランジスタの出力短絡時における発
熱を充分に押さえることができるばかりか、電流
の許容能力を充に保つことができる電流リミツタ
装置を提供しようとするものである。 This invention was developed in view of the above points, and it not only makes it possible to sufficiently suppress heat generation when the output of a power transistor that outputs an output current from an electronic control unit is short-circuited, but also increases the current tolerance capacity. The present invention aims to provide a current limiter device that can maintain the current.
すなわち、この発明に係る電流リミツタ装置に
あつては、リミツタ値を例えば２段に分けること
により、電流の許容能力を落すことなく負荷短絡
時に電流量を確実に絞ることができるようにする
ものである。 That is, in the current limiter device according to the present invention, the limiter value is divided into two stages, for example, so that the amount of current can be reliably reduced in the event of a load short circuit without reducing the current tolerance. be.
以下図面を参照してこの発明の一実施例を説明
する。第１図はその構成を示したもので、直流電
源１１からの出力電流は、抵抗１２およびこの電
流回路を開閉制御するトランジスタ１３を介して
出力端子１４に供給されるもので、この出力端子
１４に対しては図では示してないが負荷回路が接
続される。上記抵抗１２の電源１１側の一端は、
さらに抵抗１５を介して電圧を比較する動作をす
るオペレーシヨンアンプ１６（以下オペアンプと
称する）の正側端子に接続し、また抵抗１２の他
端はオペアンプ１６の反転側端子に接続する。こ
の抵抗１２，１５は電流に対応する電圧を検出す
るために用いられるもので、抵抗１５に対しては
第１および第２の定電流回路１７，１８で定めら
れる定電流が流れるように設定される。この場
合、上記第１および第２の定電流回路１７，１８
は並列的に設けられるもので、第１の定電流回路
１７はスイツチ１９によつて選択的に遮断される
ものである。すなわち、スイツチ１９の閉じた状
態では抵抗１５に「I1＋I2」の電流が流れ、スイ
ツチ１９が開いた状態では「I2」の電流が流れる
ようにされる。したがつて、オペアンプ１６の正
側端子の電位は、上記抵抗１５に流れる電流量に
よつて特定されるようになる。 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows its configuration. The output current from a DC power supply 11 is supplied to an output terminal 14 via a resistor 12 and a transistor 13 that controls opening and closing of this current circuit. Although not shown in the figure, a load circuit is connected to. One end of the resistor 12 on the power supply 11 side is
Further, the resistor 12 is connected to the positive side terminal of an operational amplifier 16 (hereinafter referred to as an operational amplifier) which operates to compare voltages, and the other end of the resistor 12 is connected to the inverting side terminal of the operational amplifier 16. The resistors 12 and 15 are used to detect the voltage corresponding to the current, and are set so that a constant current determined by the first and second constant current circuits 17 and 18 flows through the resistor 15. Ru. In this case, the first and second constant current circuits 17, 18
are provided in parallel, and the first constant current circuit 17 is selectively cut off by a switch 19. That is, when the switch 19 is closed, a current of "I 1 +I 2 " flows through the resistor 15, and when the switch 19 is open, a current of "I 2 " flows through the resistor 15. Therefore, the potential of the positive terminal of the operational amplifier 16 is determined by the amount of current flowing through the resistor 15.
上記トランジスタ１３のベースは、制御用のト
ランジスタ２０によつて制御されるもので、この
トランジスタ２０のベースには、上記オペアンプ
１６から出力信号をインバータ２１で反転した信
号、およびオペアンプ２２からの出力信号を合成
して供給する。このオペアンプ２２は基準電源２
３を、抵抗２４＋抵抗２５／抵抗２４で増幅する非反転
増
幅器で、一定電圧を作るものである。 The base of the transistor 13 is controlled by a control transistor 20, and the base of the transistor 20 receives a signal obtained by inverting the output signal from the operational amplifier 16 using an inverter 21, and an output signal from the operational amplifier 22. Synthesize and supply. This operational amplifier 22 is the reference power supply 2
3 is amplified by resistor 24+resistor 25/resistor 24 to create a constant voltage.
また、上記基準電位と出力電位とは比較回路２
６で比較し、出力電位が第２図に示すＢまで下が
つた時に上記スイツチ１９を開くように制御する
ものである。 Furthermore, the reference potential and the output potential are the same as those of the comparator circuit 2.
6, and the switch 19 is controlled to open when the output potential drops to B shown in FIG.
このように構成される電流リミツタ装置は、抵
抗１２および１５の電圧を検出してリミツタをか
ける。すなわち、抵抗１５から定電流を引き出し
て一定の電圧を保たせ、また抵抗１２に流れる電
流によつて生ずる電圧降下分の電圧を上記一定の
電圧とオペアンプ１６で比較する。 The current limiter device configured in this manner detects the voltages of the resistors 12 and 15 and applies a limiter. That is, a constant current is drawn from the resistor 15 to maintain a constant voltage, and the operational amplifier 16 compares the voltage corresponding to the voltage drop caused by the current flowing through the resistor 12 with the above-mentioned constant voltage.
すなわち、抵抗１２に対して抵抗１５に流れる
電流より上のリミツタ電流が流れると、オペアン
プ１６の出力はハイ（Ｈ）レベルとなり、したが
つてインバータ２１からの出力はロー（Ｌ）レベ
ルとなつて、トランジスタ２０のエミツタとコレ
クタ間をオフ状態とする。このため、トランジス
タ１３もオフ状態とされ、出力電流が断たれる。
例えば負荷側で短絡等があつた場合には、トラン
ジスタ１３で電源出力を断ち、電源回路の保護動
作をするようになる。 That is, when a limiter current higher than the current flowing through the resistor 15 flows through the resistor 12, the output of the operational amplifier 16 becomes a high (H) level, and therefore the output from the inverter 21 becomes a low (L) level. , the emitter and collector of the transistor 20 are turned off. Therefore, the transistor 13 is also turned off, and the output current is cut off.
For example, if a short circuit occurs on the load side, the transistor 13 cuts off the power output and protects the power supply circuit.
ここで、オペアンプ１６の抵抗１５に対して
は、定常時はスイツチ１９が閉じて「I1＋I2」の
電流が流れており、この電流値に対応した電圧が
オペアンプ１６に対して基準値として与えられて
いる。したがつて、第１段階では第２図Ａで示す
レベルでリミツタ動作をする。 Here, in the steady state, the switch 19 is closed and a current of "I 1 + I 2 " flows through the resistor 15 of the operational amplifier 16, and the voltage corresponding to this current value is applied to the operational amplifier 16 as a reference value. It is given. Therefore, in the first stage, the limiter operates at the level shown in FIG. 2A.
そして、出力電圧が第２図のＢ示す電圧まで降
下する状態となつた時に、比較回路２６の出力に
よつてスイツチ１９が開かれ、抵抗１５に流れる
リミツタ電流を図にＣ点で示すように例えば半分
となるようにする。したがつて、例えば負荷が短
絡したような時（出力電圧が零）の電流は半分に
絞られ、電源回路の例えばパワートランジスタを
効果的に保護できるものである。 When the output voltage drops to the voltage indicated by B in FIG. 2, the switch 19 is opened by the output of the comparator circuit 26, and the limiter current flowing through the resistor 15 is changed as shown by point C in the figure. For example, make it half. Therefore, for example, when the load is short-circuited (output voltage is zero), the current is halved, and the power transistor in the power supply circuit, for example, can be effectively protected.
これを具体例で示すと、例えば出力端子１４に
接続された負荷抵抗RLが例えば10Ω以上の場合
に、すなわち第１段において5V（500mA）の定
電圧出力が出力される状態で、負荷抵抗RLが例
えば10〜４Ωとされると、出力電圧が2Vととな
り、500ｍＡの定電流出力が得られる。そして、
さらに負荷抵抗RLが４Ω以下の状態となると、
この状態が比較回路２６で検出され、スイツチ１
９が開かれて250mA（1V）の定電流出力が得ら
れるようになり、図２で示したように電流制限を
２段階で切り換えるようになる。 To give a concrete example of this, for example, when the load resistance R L connected to the output terminal 14 is 10Ω or more, that is, when the first stage outputs a constant voltage output of 5V (500mA), the load resistance When R L is set to, for example, 10 to 4Ω, the output voltage becomes 2V, and a constant current output of 500mA is obtained. and,
Furthermore, when the load resistance R L becomes 4Ω or less,
This state is detected by the comparator circuit 26, and the switch 1
9 is opened to obtain a constant current output of 250mA (1V), and the current limit can be switched in two stages as shown in Figure 2.
尚、このリミツタ電流を制限しない従来の装置
にあつては、負荷短絡時の電流はＤ点である。 In a conventional device that does not limit the limiter current, the current when the load is short-circuited is at point D.
尚、上記実施例において、オペアンプ１６，２
２はそのまま電圧比較回路によつて構成してもよ
いのであり、またスイツチ１９は半導体等のスイ
ツチで構成してもようことはもちろんである。 In addition, in the above embodiment, the operational amplifiers 16 and 2
It goes without saying that 2 may be constructed as a voltage comparator circuit as it is, and switch 19 may be constructed as a semiconductor switch or the like.
以上のようにこの発明にれば、例えば負荷回路
に短絡等が発生した場合でも、電源回路を構成す
る例えばパワートランジスタに不要に大電流を流
すことなく効果的な保護動作を行なわせることの
できるものであり、また同時に負荷に対する電流
の許容能力も充分に保つことのできるものであ
る。 As described above, according to the present invention, even if a short circuit occurs in a load circuit, for example, it is possible to perform an effective protective operation without unnecessarily flowing a large current to, for example, a power transistor that constitutes a power supply circuit. At the same time, it is possible to maintain sufficient current tolerance for the load.
第１図はこの発明の一実施例に係るリミツタ装
置を説明する構成図、第２図は上記装置の動作を
説明する動作特性図である。
１１……直流電源、１２，１６……抵抗（電流
検出用）、１３……トランジスタ、１６，２２…
…オペレーシヨンアンプ、１７，１８……定電流
回路、１９……スイツチ、２６……電圧比較回
路。
FIG. 1 is a block diagram illustrating a limiter device according to an embodiment of the present invention, and FIG. 2 is an operating characteristic diagram illustrating the operation of the device. 11...DC power supply, 12, 16...Resistor (for current detection), 13...Transistor, 16,22...
...Operation amplifier, 17, 18... Constant current circuit, 19... Switch, 26... Voltage comparison circuit.
Claims (1)
から第２の抵抗回路を介して電圧信号が供給さ
れ、前記第１の抵抗回路の他端からの電圧信号が
比較電圧として供給される電圧比較回路と、 前記第２の抵抗回路に直列的に接続され、この
第２の抵抗回路に流れる電流量を設定する並列接
続した第１および第２の定電流回路と、 前記電源回路に直列に設けられ、出力電流量を
制御する可変制御素子と、 前記電圧比較回路の出力に対応して前記可変制
御素子を制御する手段と、 前記可変制御素子を介して出力される出力電流
を設定される基準値と比較して、前記出力電流が
上昇する状態で前記第１および第２の定電流回路
の一方を切り離し、前記第２の抵抗回路に流れる
電流量を減ずる２段階制御手段と、 を具備したことを特徴とする電流リミツタ装置。[Claims] 1. A voltage signal is supplied from one end of a first resistor circuit connected in series with a power supply circuit via a second resistor circuit, and the voltage signal from the other end of the first resistor circuit is compared. a voltage comparison circuit supplied as a voltage; first and second constant current circuits connected in series to the second resistance circuit and connected in parallel to set the amount of current flowing through the second resistance circuit; a variable control element that is provided in series with the power supply circuit and controls the amount of output current; means that controls the variable control element in response to the output of the voltage comparison circuit; and a variable control element that is output via the variable control element. two steps of comparing the output current with a set reference value and disconnecting one of the first and second constant current circuits while the output current is rising to reduce the amount of current flowing through the second resistance circuit; A current limiter device comprising: a control means;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14354483A JPS6037018A (en) | 1983-08-05 | 1983-08-05 | Current limiter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14354483A JPS6037018A (en) | 1983-08-05 | 1983-08-05 | Current limiter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6037018A JPS6037018A (en) | 1985-02-26 |
| JPH0475533B2 true JPH0475533B2 (en) | 1992-12-01 |
Family
ID=15341214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14354483A Granted JPS6037018A (en) | 1983-08-05 | 1983-08-05 | Current limiter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6037018A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0752372B2 (en) * | 1986-07-14 | 1995-06-05 | 株式会社ユニシアジェックス | Solenoid drive circuit |
| JPH08115135A (en) * | 1994-10-18 | 1996-05-07 | Nec Eng Ltd | Overcurrent detecting circuit |
| JP3065605B2 (en) | 1998-10-12 | 2000-07-17 | シャープ株式会社 | DC stabilized power supply |
| JP4727294B2 (en) * | 2005-05-16 | 2011-07-20 | ルネサスエレクトロニクス株式会社 | Power circuit |
| JP4845549B2 (en) * | 2006-03-23 | 2011-12-28 | ローム株式会社 | POWER SUPPLY DEVICE AND ELECTRIC DEVICE HAVING THE SAME |
| JP2011166987A (en) * | 2010-02-12 | 2011-08-25 | Fuji Electric Co Ltd | Power supply apparatus |
| JP2014100063A (en) * | 2014-03-03 | 2014-05-29 | Fuji Electric Co Ltd | Power supply device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4914341U (en) * | 1972-05-04 | 1974-02-06 | ||
| JPS5133305U (en) * | 1974-05-25 | 1976-03-11 |
-
1983
- 1983-08-05 JP JP14354483A patent/JPS6037018A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4914341U (en) * | 1972-05-04 | 1974-02-06 | ||
| JPS5133305U (en) * | 1974-05-25 | 1976-03-11 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6037018A (en) | 1985-02-26 |
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