JPS6318413B2 - - Google Patents
Info
- Publication number
- JPS6318413B2 JPS6318413B2 JP54018840A JP1884079A JPS6318413B2 JP S6318413 B2 JPS6318413 B2 JP S6318413B2 JP 54018840 A JP54018840 A JP 54018840A JP 1884079 A JP1884079 A JP 1884079A JP S6318413 B2 JPS6318413 B2 JP S6318413B2
- Authority
- JP
- Japan
- Prior art keywords
- terminal
- electrode
- transistor
- overcurrent
- control
- 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
Links
- 238000001514 detection method Methods 0.000 claims description 13
- 230000003321 amplification Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
- Dc-Dc Converters (AREA)
- Electronic Switches (AREA)
Description
【発明の詳細な説明】 本発明は過電流検出回路に関するものである。[Detailed description of the invention] The present invention relates to an overcurrent detection circuit.
従来の過電流検出回路は、検出しようとする回
路に電流検出用抵抗を直列にそう入しその両端に
生じる電圧をIC等を用いて増幅し検出していた。
この方法は回路構成が複雑となり、部品数が増え
る。また、主回路に抵抗をそう入するため損失が
増えるなどの欠点があつた。 In conventional overcurrent detection circuits, a current detection resistor is inserted in series with the circuit to be detected, and the voltage generated across the resistor is amplified and detected using an IC or the like.
This method complicates the circuit configuration and increases the number of parts. Additionally, since a resistor was inserted into the main circuit, losses increased.
本発明はスイツチングを行なつているトランジ
スタをもつ回路において、スイツチング用トラン
ジスタを同時に電流検出用素子として用いること
を特徴とする。本発明の目的は電流検出を損失が
少なくできるだけ簡単な回路で実現した過電流検
出回路を提供することにある。 The present invention is characterized in that, in a circuit having a transistor performing switching, the switching transistor is simultaneously used as a current detection element. SUMMARY OF THE INVENTION An object of the present invention is to provide an overcurrent detection circuit that realizes current detection with a circuit as simple as possible with minimal loss.
第１図は本発明の実施例であつて、１は電源側
端子、２は負荷側端子、３はON、OFF信号の入
力端子、４は警報出力端子である。TR1はスイツ
チング用のトランジスタであり、端子３より抵抗
R1を介して入つてくるON、OFF信号により端子
１，２間のスイツチングを行なう。TR2はエミツ
タがTR1のエミツタと接続され、端子３より抵抗
R2を介しベースにON、OFF信号が入つてくる。
またTR2のコレクタはTR3のエミツタに接続さ
れ、TR3のベースはTR1のコレクタに接続され
る。TR3のコレクタより警報が出力される。 FIG. 1 shows an embodiment of the present invention, in which 1 is a power supply side terminal, 2 is a load side terminal, 3 is an input terminal for ON and OFF signals, and 4 is an alarm output terminal. TR 1 is a switching transistor, and a resistor is connected from terminal 3.
Switching between terminals 1 and 2 is performed by ON and OFF signals coming in via R1 . The emitter of TR 2 is connected to the emitter of TR 1 , and a resistor is connected from terminal 3.
ON and OFF signals come into the base via R2 .
Also, the collector of TR 2 is connected to the emitter of TR 3 , and the base of TR 3 is connected to the collector of TR 1 . An alarm is output from the TR 3 collector.
この回路の動作は次のとおりである。 The operation of this circuit is as follows.
(1) OFF状態のとき、
端子３よりOFF信号が入るとTR1，TR2が
OFFとなり、端子４は開放状態になる。(1) When in the OFF state, when an OFF signal is input from terminal 3, TR 1 and TR 2
OFF, and terminal 4 becomes open.
(2) ON状態のとき、
端子３よりON信号が入るとTR1，TR2は
ON状態となる。TR1は通常状態では飽和状態
で用いられるため、TR1のコレクタエミツタ電
圧は0.2V程度で、またTR2のコレクタエミツ
タ電圧も0.2V程度となる。従つてTR3のベー
スエミツタ間電圧V3B-Eはほぼ0Vとなり、TR3
はOFF状態となり、端子４は開放状態となる。(2) In the ON state, when the ON signal is input from terminal 3, TR 1 and TR 2 will be
It becomes ON state. Since TR 1 is normally used in a saturated state, the collector-emitter voltage of TR 1 is about 0.2V, and the collector-emitter voltage of TR 2 is also about 0.2V. Therefore, the base-emitter voltage V 3B-E of TR 3 is almost 0V, and TR 3
is in the OFF state, and terminal 4 is in the open state.
過電流状態では、TR1のベース電流をIB1とし、
TR1の直流電流増幅率をh1FEとするとTR1のコ
レクタ電流がh1FE・IB1を越えようとするとTR1
が飽和領域より活性領域に移り、コレクタエミツ
タ間に電圧V1C−Ｅを生じる。これが約1V以上
になるとTR3がON状態となり、端子４はほぼ端
子１の電圧となる。従つて端子４が開放のとき通
常状態、端子１の電圧となるとき過電流状態とす
ることにより、過電流を検出することができる。 In overcurrent condition, the base current of TR 1 is I B1 ,
If the DC current amplification factor of TR 1 is h 1 FE, then when the collector current of TR 1 tries to exceed h 1 FE・I B1 , TR 1
moves from the saturation region to the active region, producing a voltage V 1 C-E between the collector and emitter. When this voltage exceeds approximately 1V, TR 3 becomes ON, and terminal 4 becomes approximately at the voltage of terminal 1. Therefore, an overcurrent can be detected by setting the normal state when the terminal 4 is open and setting the overcurrent state when the voltage reaches the terminal 1.
以上説明したように電流検出をスイツチング用
のトランジスタにより行なうため、電流検出用の
抵抗をそう入する必要がなく、それによる通常時
の損失がない。またIC等を用いる必要がなく簡
単な回路で実現できるなどの利点がある。 As explained above, since current detection is performed by a switching transistor, there is no need to insert a resistor for current detection, and there is no loss during normal operation. Another advantage is that it does not require the use of ICs and can be implemented with a simple circuit.
なお、第１図の実施例ではNPNトランジスタ
を用いた例を示したが、PNPトランジスタを用
いてもよい。また、トランジスタTR3の部分にサ
イリスタを用いることも考えられる。 Although the embodiment shown in FIG. 1 shows an example using an NPN transistor, a PNP transistor may also be used. It is also conceivable to use a thyristor for the transistor TR3 .
また、TR3のベースまたはエミツタに抵抗や電
圧シフト用のダイオード（またはツエナーダイオ
ード）をそう入することも考えられる。 It is also conceivable to insert a resistor or voltage shift diode (or Zener diode) into the base or emitter of TR 3 .
第１図は本発明の実施例の回路図である。
なお図において、１は電源入力側端子、２は出
力端子、３はON、OFF信号入力端子、４は警報
出力端子、TR1〜TR3はトランジスタ、R1，R2
は抵抗である。
FIG. 1 is a circuit diagram of an embodiment of the present invention. In the figure, 1 is the power input side terminal, 2 is the output terminal, 3 is the ON/OFF signal input terminal, 4 is the alarm output terminal, TR 1 to TR 3 are transistors, R 1 , R 2
is resistance.
Claims (1)
オフ制御端子を有し、前記入力端子から負荷端子
への過電流を検出する過電流検出回路において、
制御電極、第１の電極および第２の電極が前記制
御端子、入力端子および負荷端子にそれぞれ結合
され正常導通状態では飽和領域で動作するスイツ
チング用第１のトランジスタと、制御電極および
第１の電極が前記制御端子および入力端子にそれ
ぞれ結合され導通状態では飽和領域で動作する第
２のトランジスタと、制御電極、第１の電極およ
び第２の電極が前記負荷端子、前記第２のトラン
ジスタの第２の電極および前記検出端子にそれぞ
れ結合され、前記第１のトランジスタが過電流導
通状態時に前記第１のトランジスタの第１と第２
の電極間電圧の増加を検出して警報信号を前記検
出端子に出力する手段とを含むことを特徴とする
過電流検出回路。1 Input terminal, load terminal, detection terminal and on/off terminal
An overcurrent detection circuit that has an off control terminal and detects an overcurrent flowing from the input terminal to a load terminal,
A first switching transistor having a control electrode, a first electrode, and a second electrode coupled to the control terminal, an input terminal, and a load terminal, respectively, and operating in a saturation region in a normal conduction state; are coupled to the control terminal and the input terminal, respectively, and operate in the saturation region in a conductive state, and the control electrode, the first electrode, and the second electrode are coupled to the load terminal, and the second transistor and the detection terminal, respectively, and when the first transistor is in an overcurrent conduction state, the first and second electrodes of the first transistor
an overcurrent detection circuit, comprising: means for detecting an increase in interelectrode voltage and outputting an alarm signal to the detection terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1884079A JPS55111618A (en) | 1979-02-20 | 1979-02-20 | Overcurrent detecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1884079A JPS55111618A (en) | 1979-02-20 | 1979-02-20 | Overcurrent detecting circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55111618A JPS55111618A (en) | 1980-08-28 |
| JPS6318413B2 true JPS6318413B2 (en) | 1988-04-18 |
Family
ID=11982747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1884079A Granted JPS55111618A (en) | 1979-02-20 | 1979-02-20 | Overcurrent detecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55111618A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2611214B2 (en) * | 1987-03-23 | 1997-05-21 | 株式会社デンソー | Vehicle turn signal device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54168140U (en) * | 1978-05-18 | 1979-11-27 |
-
1979
- 1979-02-20 JP JP1884079A patent/JPS55111618A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55111618A (en) | 1980-08-28 |
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