JPH03143221A - Overcurrent detector - Google Patents
Overcurrent detectorInfo
- Publication number
- JPH03143221A JPH03143221A JP27727689A JP27727689A JPH03143221A JP H03143221 A JPH03143221 A JP H03143221A JP 27727689 A JP27727689 A JP 27727689A JP 27727689 A JP27727689 A JP 27727689A JP H03143221 A JPH03143221 A JP H03143221A
- Authority
- JP
- Japan
- Prior art keywords
- potential
- source
- current mirror
- mirror element
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 claims abstract description 19
- 239000004065 semiconductor Substances 0.000 claims description 2
- 230000005856 abnormality Effects 0.000 abstract description 2
- 230000003190 augmentative effect Effects 0.000 abstract 1
- 239000006185 dispersion Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野］
この発明は過電流検出回路に関するもので、特に保護機
能等を１チツプに集積したスマートパワーＩＣ等に有効
な過電流検出回路に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overcurrent detection circuit, and particularly to an overcurrent detection circuit that is effective for smart power ICs and the like in which protection functions and the like are integrated into one chip.
第２図にモトローラ社のＲａｎｄａｌｌ らによる従来
技術（Ｒａｎｄａｌｌ、ｅｔ ａｌ、、Ｅｌｅｃｔｒｏ
、Ｍｉｎｉ／Ｍｉｃｒ。Figure 2 shows the conventional technology by Randall et al. of Motorola (Randall, et al., Electro
, Mini/Micr.
Ｎｏｒｔｈｅａｓｔ Ｃｏｎｆ、Ｒｅｃ、、 １３１５
（１９８１ｉ））の例を示す。Northeast Conf, Rec, 1315
(1981i)).
ＮチャネルＭＯ５ＦＥＴからなる出力素子１のドレイン
１１は電源に、ソース１２は負荷３に、ゲート１３はド
ライブ回路７につながっており、制御回路６の信号によ
りドライブ回路７が出力素子１のゲート１３をバイアス
し、オンオフを制御する。The drain 11 of the output element 1 consisting of an N-channel MO5FET is connected to the power supply, the source 12 to the load 3, and the gate 13 to the drive circuit 7. The drive circuit 7 controls the gate 13 of the output element 1 according to a signal from the control circuit 6. Bias and control on/off.
カレントミラー素子２はゲート２３とドレイン２１が出
力素子１と並列につながれ、ソース２２は検出抵抗４０
につながり、検出抵抗４０の他端は出力素子１のソース
１２に接続されている。The current mirror element 2 has a gate 23 and a drain 21 connected in parallel with the output element 1, and a source 22 connected to the detection resistor 40.
The other end of the detection resistor 40 is connected to the source 12 of the output element 1.
この構成において、出力素子１とカレントミラー素子２
のセル数やチャネル幅の比を、例えばｎ：ｌとしたとき
、出力素子１のオン時の抵抗Ｒ０ｎはカレントくラー素
子２の抵抗Ｒ６ｎ２の１／ｎとなっている。したがって
検出抵抗４０（抵抗値をＲ９とする）の両端には、理想
的には
で表される主電流■１に比例する電圧ｖ３が発生ずるの
で、これを比較器５により検知し、制御回路６に入力す
る過電流検知の信号とする。In this configuration, output element 1 and current mirror element 2
When the ratio of the number of cells and the channel width is, for example, n:l, the resistance R0n of the output element 1 when it is on is 1/n of the resistance R6n2 of the current cooler element 2. Therefore, across the detection resistor 40 (resistance value R9), a voltage v3 proportional to the main current 1, which is ideally expressed by This is the overcurrent detection signal input to 6.
（発明が解決しようとする課題）
上記従来技術の場合、電圧ｖｓは理想的には■式で表さ
れるが、ＲＯｎ２に対してＲｓが十分に小さくないと、
カレントミラー素子２のソース２２の電位が出力素子１
のソース１２の電位からずれて来てしまうので、これを
さけるため、Ｒ５の値が非常に小さい値に制限されてし
まう。したがってＲ，の値が小さいということは検出電
圧ＶＳの値も非常に小さい値となるので、比較器５によ
る正確な検出が難しくなり、結果として過電流検出の電
流値が大きくばらつくことになるという欠点があった。(Problem to be Solved by the Invention) In the case of the above-mentioned conventional technology, the voltage vs is ideally expressed by the formula (■), but if Rs is not sufficiently small with respect to ROn2,
The potential of the source 22 of current mirror element 2 is the same as that of output element 1.
In order to avoid this, the value of R5 is limited to a very small value. Therefore, if the value of R is small, the value of the detection voltage VS will also be a very small value, making accurate detection by the comparator 5 difficult, and as a result, the current value for overcurrent detection will vary widely. There were drawbacks.
本発明の目的は以」二のような問題を解決した過電流検
出回路を提供することにある。An object of the present invention is to provide an overcurrent detection circuit that solves the following two problems.
（課題を解決するための手段）
上記目的を達成するため、本発明は出力素子のカレント
ミラー素子を備えた半導体装置において、カレントミラ
ー素子に定電流を流すための定電流源と、前記出力素子
の出力端子の電位と前記カレントミラー素子の出力端子
の電位とを比較することによって前記出力素子の過電流
状態を検出する手段とを具える。(Means for Solving the Problems) In order to achieve the above object, the present invention provides a semiconductor device including a current mirror element as an output element, including a constant current source for causing a constant current to flow through the current mirror element, and a constant current source for causing a constant current to flow through the current mirror element; and means for detecting an overcurrent state of the output element by comparing the potential of the output terminal of the current mirror element with the potential of the output terminal of the current mirror element.
（作 用）
本発明によれば、上記構成によって、出力素子の出力端
子の電位とカレントミラー素子の出力端子の電位とが比
較され、きわめて高精度な過電流検出が行なわれる。(Function) According to the present invention, with the above configuration, the potential of the output terminal of the output element and the potential of the output terminal of the current mirror element are compared, and overcurrent detection is performed with extremely high accuracy.
（実施例） 第１図は本発明実施例を示す。(Example) FIG. 1 shows an embodiment of the invention.
第１図に示すように、カレントミラー素子２のソース２
２にＮチャンネルデプレッション型ＭＯ５ＦＥＴからな
る定電流源４を直列に接続し、出力素子１のソース１２
の電位とカレントミラー素子２のソース２２の電位とを
比較器５により比較することによって過電流検出を行な
う。他の構成は第２図と同様である。As shown in FIG. 1, the source 2 of the current mirror element 2
A constant current source 4 consisting of an N-channel depletion type MO5FET is connected in series to the source 12 of the output element 1.
Overcurrent detection is performed by comparing the potential of the source 22 of the current mirror element 2 with the potential of the source 22 of the current mirror element 2 by the comparator 5. The other configurations are the same as in FIG. 2.
上記構成においては、出力素子１とカレントミラー素子
２のセル数の比をｎ：１とした場合、例えば主電流１１
＝ＩＩＭＡＸで過電流検出を行なうには定電流源４の電
流値Ｉ２を
Ｉ２＝ＩＩＭＡＸ／ｎ
に設定しておくだけで良い。In the above configuration, when the ratio of the number of cells of the output element 1 and the current mirror element 2 is set to n:1, for example, the main current 11
To perform overcurrent detection at =IIMAX, it is sufficient to set the current value I2 of the constant current source 4 to I2=IIMAX/n.
負荷３の正常時は出力素子１のソースの電位はカレント
ミラー素子２のソースの電位よりも常に高くなっている
が、負荷３に異常が発生し、主電流■１が大きくなって
くると、出力素子１のソース電位はしだいに低下して、
ＩＩ”ＩＩＭＡＸのときカレントよラー素子２のソース
の電位と等しくなり、さらに電流が増えようとすると、
比較器４がこれを検出し、過電流検出の信号を発生する
。When the load 3 is normal, the potential of the source of the output element 1 is always higher than the potential of the source of the current mirror element 2, but when an abnormality occurs in the load 3 and the main current ■1 becomes large, The source potential of output element 1 gradually decreases,
When II”IIMAX, the potential becomes equal to the source potential of current deflector element 2, and if the current tries to increase further,
Comparator 4 detects this and generates an overcurrent detection signal.
例えば、本発明を８０Ｖ−３Ａのスマートパワーハイサ
イドスイッチに適用した結果、過電流検出の検出電流値
のばらつきを従来型の回路の場合と比較して約１７３に
まで小さくすることができた。For example, as a result of applying the present invention to an 80V-3A smart power high-side switch, it was possible to reduce the variation in the detected current value for overcurrent detection to about 173 compared to the case of a conventional circuit.
〔発明の効果）
以上説明したように本発明によれば、きわめて高精度に
過電流を検出することができる。[Effects of the Invention] As explained above, according to the present invention, overcurrent can be detected with extremely high accuracy.
第１図は本発明の実施例を示す回路図、第２図は従来の
過電流検出回路図である。FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a conventional overcurrent detection circuit diagram.
Claims (1)
いて、カレントミラー素子に定電流を流すための定電流
源と、前記出力素子の出力端子の電位と前記カレントミ
ラー素子の出力端子の電位とを比較することによって前
記出力素子の過電流状態を検出する手段とを具えたこと
を特徴とする過電流検出回路。In a semiconductor device equipped with a current mirror element as an output element, a constant current source for passing a constant current through the current mirror element, and a potential at an output terminal of the output element and a potential at an output terminal of the current mirror element are compared. An overcurrent detection circuit comprising: means for detecting an overcurrent state of the output element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1277276A JP3011727B2 (en) | 1989-10-26 | 1989-10-26 | Overcurrent detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1277276A JP3011727B2 (en) | 1989-10-26 | 1989-10-26 | Overcurrent detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03143221A true JPH03143221A (en) | 1991-06-18 |
| JP3011727B2 JP3011727B2 (en) | 2000-02-21 |
Family
ID=17581272
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1277276A Expired - Lifetime JP3011727B2 (en) | 1989-10-26 | 1989-10-26 | Overcurrent detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3011727B2 (en) |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5422593A (en) * | 1992-05-12 | 1995-06-06 | Fuji Electric Co., Ltd. | Current-limiting circuit |
| US5903422A (en) * | 1996-06-21 | 1999-05-11 | Nec Corporation | Overcurrent sensing circuit for power MOS field effect transistor |
| US6369556B2 (en) | 2000-02-02 | 2002-04-09 | Yazaki Corporation | Power supply control device and method |
| WO2005112217A1 (en) * | 2004-05-18 | 2005-11-24 | Rohm Co., Ltd | Excess current detecting circuit and power supply device provided with it |
| JP2006173720A (en) * | 2004-12-13 | 2006-06-29 | Toshiba Microelectronics Corp | Overcurrent detector |
| US7180330B2 (en) | 2002-03-07 | 2007-02-20 | Matsushita Electric Industrial Co., Ltd. | Output circuit |
| JP2008117254A (en) * | 2006-11-07 | 2008-05-22 | Nec Electronics Corp | Power supply voltage circuit |
| JP2009130660A (en) * | 2007-11-26 | 2009-06-11 | Rohm Co Ltd | Short circuit detection circuit |
| US8004256B2 (en) | 2009-03-31 | 2011-08-23 | Panasonic Corporation | Current limiting circuit |
| JP2013083471A (en) * | 2011-10-06 | 2013-05-09 | Fuji Electric Co Ltd | Overcurrent detection circuit |
| JP2018014577A (en) * | 2016-07-20 | 2018-01-25 | 新日本無線株式会社 | Load current detection circuit |
| US10903831B2 (en) | 2018-08-09 | 2021-01-26 | Fuji Electric Co., Ltd. | Semiconductor device |
| CN113300426A (en) * | 2021-04-27 | 2021-08-24 | 珠海迈巨微电子有限责任公司 | Power device, battery management system and detection circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58146111A (en) * | 1982-02-24 | 1983-08-31 | Yokogawa Hokushin Electric Corp | Constant current circuit |
| JPS62165413A (en) * | 1986-01-17 | 1987-07-22 | Hitachi Ltd | Current mirror circuit |
| JPS6315127U (en) * | 1986-07-11 | 1988-02-01 | ||
| JPS63316113A (en) * | 1987-06-18 | 1988-12-23 | Seiko Instr & Electronics Ltd | Constant voltage circuit |
| JPH01193909A (en) * | 1988-01-29 | 1989-08-03 | Hitachi Ltd | Circuit for detecting and protecting state of semiconductor element |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4553084A (en) | 1984-04-02 | 1985-11-12 | Motorola, Inc. | Current sensing circuit |
-
1989
- 1989-10-26 JP JP1277276A patent/JP3011727B2/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58146111A (en) * | 1982-02-24 | 1983-08-31 | Yokogawa Hokushin Electric Corp | Constant current circuit |
| JPS62165413A (en) * | 1986-01-17 | 1987-07-22 | Hitachi Ltd | Current mirror circuit |
| JPS6315127U (en) * | 1986-07-11 | 1988-02-01 | ||
| JPS63316113A (en) * | 1987-06-18 | 1988-12-23 | Seiko Instr & Electronics Ltd | Constant voltage circuit |
| JPH01193909A (en) * | 1988-01-29 | 1989-08-03 | Hitachi Ltd | Circuit for detecting and protecting state of semiconductor element |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5422593A (en) * | 1992-05-12 | 1995-06-06 | Fuji Electric Co., Ltd. | Current-limiting circuit |
| US5903422A (en) * | 1996-06-21 | 1999-05-11 | Nec Corporation | Overcurrent sensing circuit for power MOS field effect transistor |
| US6369556B2 (en) | 2000-02-02 | 2002-04-09 | Yazaki Corporation | Power supply control device and method |
| US7180330B2 (en) | 2002-03-07 | 2007-02-20 | Matsushita Electric Industrial Co., Ltd. | Output circuit |
| WO2005112217A1 (en) * | 2004-05-18 | 2005-11-24 | Rohm Co., Ltd | Excess current detecting circuit and power supply device provided with it |
| JP2006173720A (en) * | 2004-12-13 | 2006-06-29 | Toshiba Microelectronics Corp | Overcurrent detector |
| JP2008117254A (en) * | 2006-11-07 | 2008-05-22 | Nec Electronics Corp | Power supply voltage circuit |
| JP2009130660A (en) * | 2007-11-26 | 2009-06-11 | Rohm Co Ltd | Short circuit detection circuit |
| US8004256B2 (en) | 2009-03-31 | 2011-08-23 | Panasonic Corporation | Current limiting circuit |
| JP2013083471A (en) * | 2011-10-06 | 2013-05-09 | Fuji Electric Co Ltd | Overcurrent detection circuit |
| JP2018014577A (en) * | 2016-07-20 | 2018-01-25 | 新日本無線株式会社 | Load current detection circuit |
| US10903831B2 (en) | 2018-08-09 | 2021-01-26 | Fuji Electric Co., Ltd. | Semiconductor device |
| CN113300426A (en) * | 2021-04-27 | 2021-08-24 | 珠海迈巨微电子有限责任公司 | Power device, battery management system and detection circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3011727B2 (en) | 2000-02-21 |
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