JPS6328260A - Overcurrent protective circuit of switching power source - Google Patents
Overcurrent protective circuit of switching power sourceInfo
- Publication number
- JPS6328260A JPS6328260A JP16850586A JP16850586A JPS6328260A JP S6328260 A JPS6328260 A JP S6328260A JP 16850586 A JP16850586 A JP 16850586A JP 16850586 A JP16850586 A JP 16850586A JP S6328260 A JPS6328260 A JP S6328260A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- overcurrent
- secondary side
- switching power
- power supply
- 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
- 230000001681 protective effect Effects 0.000 title 1
- 238000001514 detection method Methods 0.000 claims description 12
- 230000007423 decrease Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000010355 oscillation Effects 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 238000011084 recovery Methods 0.000 description 2
- FBOUIAKEJMZPQG-AWNIVKPZSA-N (1E)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pent-1-en-3-ol Chemical compound C1=NC=NN1/C(C(O)C(C)(C)C)=C/C1=CC=C(Cl)C=C1Cl FBOUIAKEJMZPQG-AWNIVKPZSA-N 0.000 description 1
- 208000010201 Exanthema Diseases 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 201000005884 exanthem Diseases 0.000 description 1
- 206010037844 rash Diseases 0.000 description 1
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Abstract
Description
【発明の詳細な説明】
〔概要〕
本発明のスイッチング電源の過電流保護回路は、二次側
で過電流を検出し、フォトカプラにより一次側にフ仁
１バツクして供給電圧を低下・已しめる方式であり、
フォトカプラの発光素子に逆方向バイアス電圧を供給す
るとともに、過電流検出によって発光せしめ、フォトト
ランジスタの導通により、スイッチングトランジスタの
ヘース電ｉＩｉ！ｔを側流せしめるように構成したもの
である。[Detailed Description of the Invention] [Summary] The overcurrent protection circuit for a switching power supply of the present invention detects overcurrent on the secondary side, and connects the overcurrent to the primary side using a photocoupler.
This is a method in which the supply voltage is lowered or increased by one step back.A reverse bias voltage is supplied to the light-emitting element of the photocoupler, and the light is emitted by detecting an overcurrent.The conduction of the phototransistor causes the switching transistor's Heath voltage ii! The structure is such that t is allowed to flow to the side.
本発明は、スイッチング電源における過電流保護回路の
改良に関する。The present invention relates to improvements in overcurrent protection circuits in switching power supplies.
スイッチング電源の二次側過電流保護回路には、一次側
で過電流を検出して一次側の発振を停止する方法とか、
二次側で過電流を検知して二〕次側電流通路を遮断また
は一次側発振を停止する等の方法がある。The secondary side overcurrent protection circuit of a switching power supply has a method that detects overcurrent on the primary side and stops oscillation on the primary side.
There are methods such as detecting overcurrent on the secondary side and cutting off the secondary side current path or stopping the primary side oscillation.
し２かし、電源垂下特性を持たせ、旧つ二次側短絡に対
しても安全に保護機能を持たせるとと７）に、復帰が容
易なものは少なく、これらの特性を備えた簡易な過電流
保護回路が求められている。However, there are few products that have power supply droop characteristics and have a safe protection function against short circuits on the secondary side. There is a need for a reliable overcurrent protection circuit.
第３図はスイッチング電源のブし１７９図であり、二次
側で過電流を検出し、一次側の発振を停止する過電流保
護回路例を示したものである。FIG. 3 is a schematic diagram of a switching power supply, showing an example of an overcurrent protection circuit that detects overcurrent on the secondary side and stops oscillation on the primary side.
このスイッチング電源は、スイッチングトランスタ０１
がスイッチングトランス′ＦによるｉＩＥ（Ｍぷで発振
し、二次側に設けられた整流回路（ダイオードＤｌおよ
びコンデンリ−Ｃ１）で所定の直流電圧を１２する周知
のものである。This switching power supply is a switching transformer 01
This is a well-known system in which the switching transformer 'F oscillates at iIE (Mp), and a rectifier circuit (diode Dl and capacitor C1) provided on the secondary side generates a predetermined DC voltage.
過電流検出は抵抗１？１および１−ランンスタＱ２で行
われ、設定した過電流が負荷ｌに流れると、抵抗Ｒ１に
よる電圧降下でトランジスタＱ２がオンとなり、フォト
カプラＧ１の発光素子Ｇｌｂが発光してフォトサイリス
クの受光素子Ｇ１ａｆＪ＜導通し、一次側の供給電圧■
が低下して発振を停止させる。Overcurrent detection is performed by resistor 1?1 and 1-run star Q2, and when the set overcurrent flows to load l, transistor Q2 is turned on due to the voltage drop across resistor R1, and light emitting element Glb of photocoupler G1 emits light. The photoreceiving element G1afJ of the photosilisk is conductive, and the supply voltage on the primary side is
decreases and stops oscillation.
以上の結果、二次側電圧は０■となり、設定された過電
流以上で電圧が０となる電源垂下特性が得られる。As a result of the above, the secondary side voltage becomes 0■, and a power supply drooping characteristic in which the voltage becomes 0 when the overcurrent exceeds the set value is obtained.
なお、フォトカプラは一次側と二次側とを絶縁する効果
を与えるものである。Note that the photocoupler provides an effect of insulating the primary side and the secondary side.
上記例の過電流保護回路は、一次側にフォトサイリスク
を使用しているため復帰機能はなく、過電流が発生した
ときは、一次側電源を切断し、二次側の過′ｔｈ流原因
を除去した後、電源を再投入しなければならないという
不便がある。The overcurrent protection circuit in the above example uses photothyrist on the primary side, so there is no recovery function, and when an overcurrent occurs, the primary side power is cut off, and the overcurrent on the secondary side is removed. There is an inconvenience that the power must be turned on again after removing the .
本発明は電源垂下特性を倫え且つ復帰可能な簡易な過電
流保護回路を提供することを目的とするものである。SUMMARY OF THE INVENTION An object of the present invention is to provide a simple overcurrent protection circuit that maintains power supply droop characteristics and is capable of recovery.
ト記目的のため、本発明のス・イツチング電源の過電流
保護回路は、第１図本発明の原理説明図に示すように、
二次側においてＩ″Ｌ荷の過電流状態を検出゛４る検出
手段（Ｒ１）と、
二次側出力電圧に対して逆方向の電圧を発生する発生手
段（２）を設け、この電圧をフォトカプラの発光素子（
Ｑ３ｂ）にバイアス電圧として供給するとともに、前記
検出手段により過電流状態を検出したとき、該発光素子
を発光せしめる１段（Ｑ２）と、
該フォトトランジスタ（Ｑ３ａ）の導通により、一次側
スイッチングトランスタ（Ｑ１）のペース電流を側流し
二次側出力電圧を低下せしめる手段（３）と、
を設けたものである。For this purpose, the overcurrent protection circuit of the switching power supply of the present invention detects the overcurrent state of the I″L load on the secondary side, as shown in FIG. 1, a diagram explaining the principle of the present invention. A detection means (R1) is provided, and a generation means (2) is provided that generates a voltage in the opposite direction to the secondary side output voltage, and this voltage is applied to the photocoupler light emitting element (
Q3b) as a bias voltage, and when the detection means detects an overcurrent state, conduction between the first stage (Q2) that causes the light emitting element to emit light and the phototransistor (Q3a) causes the primary side switching transformer to be activated. Means (3) for diverting the pace current of (Q1) to lower the secondary side output voltage is provided.
供給電圧と逆方向の電圧を発生してフＡｌ・カブラの発
光素子に逆バイアス電圧を供給し、過電流検出により発
光せしめる。A voltage in the opposite direction to the supply voltage is generated to supply a reverse bias voltage to the light emitting element of the aluminum fogger, which causes it to emit light by detecting an overcurrent.
これにより、負荷が完全短絡してＯＶとなっても発光を
継続する。As a result, light emission continues even if the load is completely short-circuited and becomes OV.
一次側スイツチングトランジスタのヘ−スミ流を減少せ
しめると、発振矩形波のデユーティが低下して二次側電
圧が低下するがら、フォＩ・カプラにより過電流検出を
フィートバンクしてペース電流を側流する。これにより
、二次側電圧が低下する。When the Hesmi current of the primary side switching transistor is reduced, the duty of the oscillating square wave decreases and the secondary side voltage decreases. Flow. This causes the secondary voltage to drop.
以上により、過電流検出とともにスイッチング電源保護
に必要な電圧まで低下する電源垂下特性が得られ、また
フォトカプラは逆バイアス電圧が加えられているため発
光を継続し、過電流原因が除去されるとスイッチング電
源の動作は正常に復帰する。As a result of the above, a power droop characteristic is obtained in which the voltage drops to the level required for protection of the switching power supply when overcurrent is detected, and since a reverse bias voltage is applied to the photocoupler, it continues to emit light, and when the cause of the overcurrent is removed. The operation of the switching power supply returns to normal.
本発明の実施例を第２図を参照しつつ説明する。 An embodiment of the present invention will be described with reference to FIG.
第２図（ａ）は、正電圧を負荷１に供給スイソチングミ
源のブ１１ツク図であって、
Ｒ１は過電流検出用抵抗、
Ｃ３は、発光素子（発光ダイオード）Ｃ３ｂと、受光素
子がフォトトランジスタＱ３ａで構成されるフォトカプ
ラ、
２は、整流用ダイオードＤ２およびコンデンサＣ２で構
成される逆電圧（負電圧）発生回路で、その出力は発光
ダイオ−１”Ｃ３ｂ４こ供給されるもの、
３は、スイッチングトランジスタＱｌのベース回路に挿
入され、フォトトランジスタＱ３ａが導通したときヘ−
スミ流を側流する側流回路、であり、その他、第２図と
同−符壮は同一対象物を表す。FIG. 2(a) is a block diagram of a switching source that supplies positive voltage to load 1, where R1 is a resistor for overcurrent detection, C3 is a light emitting element (light emitting diode) C3b, and a light receiving element is a photodetector. 2 is a reverse voltage (negative voltage) generation circuit composed of a rectifying diode D2 and a capacitor C2, the output of which is supplied to the light emitting diode 1''C3b4; 3 is a photocoupler made up of a transistor Q3a; , is inserted into the base circuit of the switching transistor Ql, and when the phototransistor Q3a conducts, the
This is a side flow circuit that flows the Sumi flow sideways, and the same symbols as in Fig. 2 represent the same objects.
以上構成の過電流保護回路の動作は以下の通りである。The operation of the overcurrent protection circuit having the above configuration is as follows.
負荷ｌに過電流原因が発生し、過電流検出用抵抗Ｒ１に
所定電流以」−の過電ｄｔが流れると、過電流検出用ト
ランジスタＱ２が導通し、フォトカプラの発光素子Ｑ３
ｂに電流１１が流れ、発光する。When an overcurrent cause occurs in the load L and an overcurrent dt of a predetermined current or more flows through the overcurrent detection resistor R1, the overcurrent detection transistor Q2 becomes conductive, and the photocoupler's light emitting element Q3
A current 11 flows through b, and light is emitted.
スイッチングトランス′ｒの二次側には正負両極性のパ
ルスが誘起されているから、二次側（負荷１）が完全短
絡されても負電圧は発生し、上記動作は継続される。Since pulses of both positive and negative polarities are induced on the secondary side of the switching transformer 'r, even if the secondary side (load 1) is completely short-circuited, a negative voltage is generated and the above operation continues.
上記過電流検出によって発光素子Ｑ３ｂか発光すると、
フォトトランジスタＱ３ａが導通し、以下の動作が行わ
れる。When the light emitting element Q3b emits light due to the overcurrent detection,
Phototransistor Q3a becomes conductive, and the following operation is performed.
ダイオードＤ３およびコンデンサＣ３により正バイアス
電圧を発生し、フォトトランジスタＱ３ａの導通により
、抵抗Ｒ２を介して側流用トランジスタＱ４が導通し、
側流電流Ｉ２が流れる。A positive bias voltage is generated by the diode D3 and the capacitor C3, and the conduction of the phototransistor Q3a causes the side flow transistor Q4 to conduct through the resistor R2.
A side current I2 flows.
これにより、ヘ−ス回路電流ＩｔかトランジスタＱ４に
側流したことになり、スイッチングトランジスタＱ１の
ベース電流１ｂが減少する。As a result, the base circuit current It flows to the transistor Q4, and the base current 1b of the switching transistor Q1 decreases.
このため、発振周期は低下し、且つオン時間が減少（デ
ユーティが低下）して二次側に発生ずる電圧が低下する
。Therefore, the oscillation period decreases, the on-time decreases (duty decreases), and the voltage generated on the secondary side decreases.
この結果、負荷１の電流が制限され、二次側過電流によ
るスイッチング電源の破壊を防止する。As a result, the current of the load 1 is limited, and destruction of the switching power supply due to secondary side overcurrent is prevented.
第２図（ｂｌは上記動作特性を表したもので、過電流検
出電流１０を検出したとき、一次側は発振を継続したま
ま二次側電圧をＥＯよりＥｌに低下せしめ、電源垂下特
性を持たせることができる。Figure 2 (bl represents the above operating characteristics. When an overcurrent detection current of 10 is detected, the primary side continues to oscillate and the secondary side voltage is lowered from EO to El, resulting in a power droop characteristic. can be set.
以上のごとく、逆バイアス電圧によって発光を維持され
たフォトトランジスタを使用して、安価な過電流保護回
路を提供することができる。As described above, an inexpensive overcurrent protection circuit can be provided using a phototransistor whose light emission is maintained by a reverse bias voltage.
本発明は、逆電圧によって発光維持されたフォトトラン
ジスタで構成されるフ第１・カプラを使用し、電源垂下
特性を備え且つ完全短絡時にも安定した保護機能が得ら
れるとともに、復帰が容易な保護回路を安価に提供する
ことができ、簡易な装置電源における効果は極めて人で
ある。The present invention uses a first coupler consisting of a phototransistor that maintains light emission by a reverse voltage, and has a power droop characteristic and provides a stable protection function even in the event of a complete short circuit, as well as protection that can be easily restored. The circuit can be provided at a low cost, and the effect on a simple device power supply is extremely simple.
第１図は本発明の原理説明図、
第２図ｔａ＋は実施例のスイッチング電源ブロック図、
第２図（ｂｌは動作特性を表す図、
第３図は従来のスイッチング電源ブロック図、である。
図中、
１は負荷、
２は逆電圧発生回路、
３は側流回路、
Ｒ１は抵抗で構成される過電流検出手段、Ｒ２は抵抗、
Ｃ１，Ｃ２，Ｃ３は整流用のコンデンサ、Ｑｌはスイッ
チングトランジスタ、
Ｃ２は過電流検出用トランジスタ、
Ｃ３はフォトカブラで、Ｃ３ａはフス）・トランジスタ
で構成される受光素子、Ｃ３ｂは発光素子、Ｃ４は側流
用トランジスタ、
１） １〜Ｄ３はダイオード、
Ｔはスイッチングトランス、
である。
萌Ｐ疹県い 品FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 (ta+) is a block diagram of a switching power supply of an embodiment, FIG. 2 (bl is a diagram showing operating characteristics, and FIG. 3 is a block diagram of a conventional switching power supply). In the figure, 1 is a load, 2 is a reverse voltage generation circuit, 3 is a side current circuit, R1 is an overcurrent detection means composed of a resistor, R2 is a resistor, C1, C2, and C3 are rectifying capacitors, and Ql is a switching circuit. Transistor, C2 is a transistor for overcurrent detection, C3 is a photocoupler, C3a is a light-receiving element composed of a FUS) transistor, C3b is a light-emitting element, C4 is a side flow transistor, 1) 1 to D3 are diodes, T is a It is a switching transformer. MoeP rash prefecture product
Claims (1)
スタ（Ｑ１）を発振せしめ、二次側に発生した電圧を整
流して所定電圧を負荷に供給するスイッチング電源にお
いて、 前記二次側において負荷の過電流状態を検出する検出手
段（Ｒ１）と、 前記所定電圧に対して逆方向の電圧を発生する発生手段
（２）を設け、この電圧をフォトカプラの発光素子（Ｑ
３ｂ）にバイアス電圧として供給するとともに、前記検
出手段により過電流状態を検出したとき、該発光素子を
発光せしめる手段（Ｑ２）と、 該フォトトランジスタ（Ｑ３ａ）の導通により、一次側
スイッチングトランジスタ（Ｑ１）のベース電流を側流
し前記所定電圧を低下せしめる手段（３）と、 を設けたことを特徴とするスイッチング電源の過電流保
護回路。[Scope of Claims] A switching power supply that causes a switching transistor (Q1) to oscillate on the primary side of a switching transformer, rectifies the voltage generated on the secondary side, and supplies a predetermined voltage to a load, comprising: A detection means (R1) for detecting an overcurrent state and a generation means (2) for generating a voltage in the opposite direction to the predetermined voltage are provided, and this voltage is applied to a light emitting element (Q) of a photocoupler.
3b) as a bias voltage, and when an overcurrent state is detected by the detection means, the primary side switching transistor (Q1 An overcurrent protection circuit for a switching power supply, comprising: means (3) for lowering the predetermined voltage by diverting the base current of the switching power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16850586A JPS6328260A (en) | 1986-07-17 | 1986-07-17 | Overcurrent protective circuit of switching power source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16850586A JPS6328260A (en) | 1986-07-17 | 1986-07-17 | Overcurrent protective circuit of switching power source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6328260A true JPS6328260A (en) | 1988-02-05 |
Family
ID=15869305
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16850586A Pending JPS6328260A (en) | 1986-07-17 | 1986-07-17 | Overcurrent protective circuit of switching power source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6328260A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010502533A (en) * | 2006-08-31 | 2010-01-28 | オーチス エレベータ カンパニー | Managing power fluctuations in elevator drive systems |
| JP2010124648A (en) * | 2008-11-21 | 2010-06-03 | Nichicon Corp | Switching power supply apparatus |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58107924A (en) * | 1981-12-22 | 1983-06-27 | Nec Corp | Constant current supply device |
| JPS6091864A (en) * | 1983-10-20 | 1985-05-23 | Sanken Electric Co Ltd | Dc/dc converter |
| JPS60197165A (en) * | 1984-03-16 | 1985-10-05 | Sanken Electric Co Ltd | Self-excited oscillator |
| JPS60204261A (en) * | 1984-03-27 | 1985-10-15 | Sanken Electric Co Ltd | Self-excited oscillator |
| JPS61124268A (en) * | 1984-11-20 | 1986-06-12 | Matsushita Electric Ind Co Ltd | Pulse drive controlling method of ringing choke converter |
-
1986
- 1986-07-17 JP JP16850586A patent/JPS6328260A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58107924A (en) * | 1981-12-22 | 1983-06-27 | Nec Corp | Constant current supply device |
| JPS6091864A (en) * | 1983-10-20 | 1985-05-23 | Sanken Electric Co Ltd | Dc/dc converter |
| JPS60197165A (en) * | 1984-03-16 | 1985-10-05 | Sanken Electric Co Ltd | Self-excited oscillator |
| JPS60204261A (en) * | 1984-03-27 | 1985-10-15 | Sanken Electric Co Ltd | Self-excited oscillator |
| JPS61124268A (en) * | 1984-11-20 | 1986-06-12 | Matsushita Electric Ind Co Ltd | Pulse drive controlling method of ringing choke converter |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010502533A (en) * | 2006-08-31 | 2010-01-28 | オーチス エレベータ カンパニー | Managing power fluctuations in elevator drive systems |
| US8333265B2 (en) | 2006-08-31 | 2012-12-18 | Otis Elevator Company | Elevator system with regulated input power |
| JP2010124648A (en) * | 2008-11-21 | 2010-06-03 | Nichicon Corp | Switching power supply apparatus |
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