JPS5850020A - Constant voltage circuit protected from short-circuit - Google Patents
Constant voltage circuit protected from short-circuitInfo
- Publication number
- JPS5850020A JPS5850020A JP56148145A JP14814581A JPS5850020A JP S5850020 A JPS5850020 A JP S5850020A JP 56148145 A JP56148145 A JP 56148145A JP 14814581 A JP14814581 A JP 14814581A JP S5850020 A JPS5850020 A JP S5850020A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- circuit
- load
- short
- output
- 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
- 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
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)
- Electronic Switches (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は、負荷の短絡事故による回路素子の破壊を防
止するようにした短絡保護付電圧回路に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage circuit with short-circuit protection that prevents damage to circuit elements due to a load short-circuit accident.
従来、直流定電圧回路の過電流保護回路としては、最大
負荷電流を設定して、負荷抵抗が減少しても負荷電流が
設定値を越えないで出力電流が一定に保たれる定電流型
の定電圧回路や、また最大負荷電流を越えて負荷抵抗が
小さくなった場合、出力電圧が低下すると同時に出力電
流も低減する電流低減型の定電圧回路、更に最大負荷電
流を越える電流が流れると、ヒユーズ、リレー、ＳＣＲ
等で電流を完全に遮断してしまう電流遮断型の定電圧回
路等が提供されていた。Conventionally, overcurrent protection circuits for DC constant voltage circuits have been of the constant current type, which sets the maximum load current and keeps the output current constant without causing the load current to exceed the set value even if the load resistance decreases. Constant voltage circuits, current reduction type constant voltage circuits that reduce the output voltage and output current at the same time when the maximum load current is exceeded and the load resistance becomes small, and furthermore, when the current exceeding the maximum load current flows, Hughes, relay, SCR
A current cut-off type constant voltage circuit, etc., which completely cuts off the current, has been provided.
ところが、上記定電流型定電圧回路の場合、負荷の短絡
時に制御用トランジスタに全入力電圧が、ｈｌかり制御
用トランジスタの電力損失が非常に大きくなり、それに
耐えられるような大きな放熱板を設けるか、あるいは容
量の大きな制御用トランジスタを使用する必要があり、
コスト高になる欠点があった。また、上記電流低減型定
電圧回路の場合も負荷電流を検出して保護回路を働かせ
ているため、負荷短絡時にも出力電流を０にできず制御
用トランジスタの電力損失が大きい。更に、上記電流遮
断型定電圧回路の場合、負荷の短絡時には制御用トラン
ジスタに電流が流れないため電力損失はないが、一度保
護回路が働くと負荷が正常にもっても自動的に復帰せず
、ヒユーズを取替えたり、セット操作をする必要があり
回路が複雑となって高価で小形化が不可能であった。However, in the case of the above-mentioned constant current type constant voltage circuit, when the load is short-circuited, the total input voltage to the control transistor is hl, and the power loss of the control transistor becomes extremely large, so it is necessary to provide a large heat sink to withstand this. , or it is necessary to use a control transistor with a large capacity,
It had the disadvantage of high cost. Furthermore, in the case of the current reduction type constant voltage circuit as well, since the load current is detected and the protection circuit is operated, the output current cannot be reduced to 0 even when the load is short-circuited, and the power loss of the control transistor is large. Furthermore, in the case of the above-mentioned current cutoff type constant voltage circuit, when the load is short-circuited, no current flows through the control transistor, so there is no power loss, but once the protection circuit is activated, it will not automatically recover even if the load returns to normal. It was necessary to replace fuses and perform set operations, making the circuit complicated, expensive, and impossible to miniaturize.
この発明は、簡単な構成で負荷に短絡事故が発生しても
制御用トランジスタがＯＦＦして過負荷による回路素子
の破壊を防止し、かつ負荷側の異常が解除、されれば自
動的に復帰させることもできる短絡保護付電圧四路を提
供することを目的とする。This invention has a simple configuration, and even if a short-circuit accident occurs in the load, the control transistor is turned off to prevent circuit elements from being destroyed due to overload, and it is automatically restored when the abnormality on the load side is resolved. The purpose of the present invention is to provide a four-way voltage circuit with short-circuit protection that can also be used.
この発明は、上記の目的を連成するために、オペアンプ
に、特定の入力信号電圧を境にその出力レベルが急激に
反転する転位電圧を有した同相入力電圧特性のものを使
用したことを特徴とする。In order to achieve the above object, the present invention uses an operational amplifier with common-mode input voltage characteristics that has a transition voltage whose output level rapidly reverses at a specific input signal voltage. shall be.
以下、この発明の実施例を図面に基づいて詳細に説明す
る。Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
第１図は、この発明に係る短絡保護付アナログ方式定電
圧回路の回路例を示し、図において、出力電圧制御用ト
ランジスタ１のエミッタには非安定化入力電圧Ｅが印加
され、トランジスタ１の出力はコンデンサ４で平滑され
、出力電圧Ｖが負荷に供給される。また、オペアンプ２
は非反転入力端子に出力電圧Ｖを抵抗８．９で分圧した
電圧ＶＤが、反転入力端子に抵抗７を介して入力電圧Ｅ
が加えられた定電圧ダイオード３によって与えられる基
準電圧■ｚがそれぞれ入力されている。そして、オペア
ンプ２は基準電圧ｖＺと分圧電圧ＶＤとの差を増幅し、
抵抗６を通して出力電圧制御用トランジスタ１のベース
電流を調整することで、負荷変動に対して一定の出力電
圧Ｖが確保されるのは周知の通°りである。そして、従
来は、負荷が何等かの原因で短絡すると、ＶＺ＞ＶＤ−
０となって、オペアンプ３の出力はＬレベルに固定され
る結果、出力電圧制御用トランジスタ１は過電流によっ
て破壊されるから種々の対策が施されていたことは上述
のとうりである。FIG. 1 shows a circuit example of an analog type constant voltage circuit with short circuit protection according to the present invention. In the figure, an unregulated input voltage E is applied to the emitter of an output voltage control transistor 1, and an output is smoothed by a capacitor 4, and the output voltage V is supplied to the load. Also, operational amplifier 2
The voltage VD obtained by dividing the output voltage V by a resistor 8.9 is applied to the non-inverting input terminal, and the input voltage E is applied to the inverting input terminal via a resistor 7.
The reference voltage ■z given by the constant voltage diode 3 to which is added is inputted. Then, the operational amplifier 2 amplifies the difference between the reference voltage vZ and the divided voltage VD,
It is well known that by adjusting the base current of the output voltage control transistor 1 through the resistor 6, a constant output voltage V can be secured against load fluctuations. Conventionally, if the load is short-circuited for some reason, VZ>VD-
0, the output of the operational amplifier 3 is fixed at L level, and as a result, the output voltage control transistor 1 is destroyed by overcurrent, so various countermeasures have been taken as described above.
なお、１０は自動復帰用ダイオードである。Note that 10 is an automatic recovery diode.
ここで注目すべきことは、特性上数多くの種類が存在す
るオペアンプはその同相入力電圧特性によって２種類に
大別されることである。すなわち、１つは、第２図に示
すように、オペアンプの基本機能を実現するリニア領域
と飽和領域よりなる種類で、これは７０９，７４１系で
代表され、一般に常用されているものである。他の１つ
は、第３図に示すように、上記２つの領域と、特定の入
力電圧を境にして出力が急激、に反転する転位電圧ＶＡ
を持った変位領域とからなる種類で、これは４５５８系
で代表される。そして、この発明に係るオペアンプは変
位領域を持った後者の種類のオペアンプを使用するので
ある。What should be noted here is that operational amplifiers, which come in many types due to their characteristics, can be roughly divided into two types depending on their common-mode input voltage characteristics. Specifically, one type, as shown in FIG. 2, consists of a linear region and a saturation region that realize the basic functions of an operational amplifier, and this type is represented by the 709,741 series and is commonly used. The other is, as shown in Figure 3, the transition voltage VA where the output suddenly reverses between the above two regions and a specific input voltage.
This type is represented by the 4558 series. The operational amplifier according to the present invention uses the latter type of operational amplifier having a displacement region.
第３図に示す特性は、＋１５Ｖの電源によった場合を示
しでいるが、転位電圧ＶＡは一１５Ｖにさしかかる手前
に存在する。よって、このオペアンプを＋３０Ｖの単一
電源で使用すれば、−１５ＶがＯｖとなり、転位電圧Ｖ
ＡはＯｖの手前数Ｖの所に存在することになる。つまり
、第１５！！ｌに示した回路の入力電圧Ｅは＋３０Ｖに
なっている。The characteristics shown in FIG. 3 show the case where a power supply of +15V is used, but the transposition voltage VA exists just before reaching -15V. Therefore, if this operational amplifier is used with a single power supply of +30V, -15V becomes Ov, and the transposition voltage V
A will exist a number V before Ov. In other words, number 15! ! The input voltage E of the circuit shown in FIG. 1 is +30V.
その結果、負荷が短絡し、ＶＤが０に向かって５−
下降しても、ＶＯ−Ｏとなる直前でオペアンプ２は転位
電圧ＶＡ （＞Ｏ）に達する。そして、ｖＡ＜ＶＺとな
るので、その出力がＨレベルに急激に反転し、出力電圧
制御用トランジスタ１を急速にＯＦＦさせる。その後、
ＶＯ−Ｏとなるが、オペアンプ３は変位領域に追い込ま
れる結果、出力電圧制御用トランジスタ１はＯＦＦ状態
に保持され、上述の如き素子の破壊は未然に防止される
のである。そして負荷の短絡状態が解除されると、抵抗
７とダイオード１０を介して負荷に電流が供給され、分
圧・電圧ＶＤが上昇する。分圧電圧ＶＤが上昇して、Ｖ
Ｄ＞ＶＡになるとオペアンプ２の出力はＬレベルに反転
して、出力電圧制御用トランジスタ１がＯＮする結果、
出力電圧■ は自動的に復帰する。なお、自動ｖＡ帰を
させない場合には、ダイオード１０を外せばよい。すな
わち、負荷の知略状態が解除されたときに、負荷への電
流供給がないため、出力電圧制御用トランジスタ１がＯ
ＦＦ状態を継続するのである。この場合に、復帰させる
ときには一旦入力電圧をＯＦＦにして電源６−
を再投入すれば良い。As a result, even if the load is short-circuited and VD drops by 5-degrees toward 0, the operational amplifier 2 reaches the transposition voltage VA (>O) just before reaching VO-O. Then, since vA<VZ, the output is rapidly inverted to H level, and the output voltage control transistor 1 is rapidly turned off. after that,
However, as a result of the operational amplifier 3 being forced into the displacement region, the output voltage control transistor 1 is held in the OFF state, and the above-mentioned destruction of the element is prevented. When the short-circuited state of the load is released, current is supplied to the load via the resistor 7 and diode 10, and the divided voltage VD increases. As the divided voltage VD increases, V
When D>VA, the output of the operational amplifier 2 is inverted to L level, and the output voltage control transistor 1 is turned on.
The output voltage ■ will automatically recover. Note that if automatic vA return is not to be performed, diode 10 may be removed. In other words, when the load is released from the unintentional state, there is no current supply to the load, so the output voltage control transistor 1 is turned off.
The FF state continues. In this case, when returning to normal operation, it is sufficient to turn off the input voltage once and then turn on the power supply 6- again.
次に、この発明に係る短絡保護付電圧回路をスイッチン
グレギュレータに適用した場合には例えば第４図および
第５図に示すような回路構成となる。Next, when the voltage circuit with short circuit protection according to the present invention is applied to a switching regulator, the circuit configuration will be as shown in FIGS. 4 and 5, for example.
第４図において、この回路は、自動復帰型の短絡保護付
スイッチングレギュレータを示しており、第１図に示し
た回路に、チョークコイル１２と、チョークコイル１２
のサージを吸収するダイオード１１と、安定したスイッ
チング動作を得るための正帰還用抵抗１３を付加しであ
る。 このような回路構成としたので、出力電圧■の変
動はオペアンプ２で検出して、その出力はＨレベルとＬ
レベルを繰り返し、これに同期して出力電圧Ｉｌｌ ｍ
用トランジスタ１がＯＮとＯＦＦを繰り返して負荷に安
定した出力を供給する。このとき、負荷に短絡事故が発
生すると上述のようにオペアンプ２の出力はＨレベルと
なって出力電圧制御用トランジスタ１は０ＦＦＬ、過電
流が流れることなく保護される。そして負荷の知略状態
が解除されると、抵抗５．抵抗′１３．抵抗１４を通し
て抵抗９に電流が流れ、オペアンプ２の非反転入力端子
に与えられる電圧Ｖ＋は転位電圧ＶＡよりも大きくなっ
て、出力はＬレベルに反転し、出力電圧制御用トランジ
スタ１はＯＮＬ、て、出力電圧Ｖは自動的に復帰するの
である。In FIG. 4, this circuit shows an automatic reset type switching regulator with short-circuit protection, and the circuit shown in FIG.
A diode 11 for absorbing surges and a positive feedback resistor 13 for stable switching operation are added. With this circuit configuration, fluctuations in the output voltage ■ are detected by operational amplifier 2, and its output is divided into H level and L level.
The level is repeated, and in synchronization with this, the output voltage Ill m
Transistor 1 repeatedly turns on and off to supply a stable output to the load. At this time, if a short-circuit accident occurs in the load, the output of the operational amplifier 2 becomes H level as described above, and the output voltage control transistor 1 is set to 0FFL, so that no overcurrent flows and is protected. Then, when the load's intelligence state is released, the resistance 5. Resistance '13. Current flows through the resistor 9 through the resistor 14, and the voltage V+ applied to the non-inverting input terminal of the operational amplifier 2 becomes larger than the transition voltage VA, the output is inverted to L level, and the output voltage control transistor 1 is ONL. , the output voltage V automatically recovers.
なお、負荷短絡時には、オペアンプ２のＨレベル出力が
帰還抵抗１３、抵抗１４を介して非反転入力端子に印加
されるが、この自動復帰促進用のダイオード１０がＯＮ
している結果、抵抗８．９からなる直列回路にはダイオ
ード１０の順方向電圧ＶＦがかかる。よって、この時の
非反転入力端子に入力される電圧■＋は、Ｖ十−ＶＦＸ
Ｒ９／（Ｒ１４＋Ｒ９）である。そこで、この回路例で
は、負荷短絡時に確実にＶ＋＜ＶＡとなるように抵抗１
４の抵抗値Ｒ１４は選定しである。Note that when the load is short-circuited, the H level output of the operational amplifier 2 is applied to the non-inverting input terminal via the feedback resistor 13 and the resistor 14, but the diode 10 for promoting automatic recovery is turned on.
As a result, the forward voltage VF of the diode 10 is applied to the series circuit consisting of the resistor 8.9. Therefore, the voltage ■+ input to the non-inverting input terminal at this time is V + - VFX
R9/(R14+R9). Therefore, in this circuit example, in order to ensure that V+<VA when the load is short-circuited,
The resistance value R14 of 4 is selected.
次いで第５図は負荷が短絡状態を解除されても、自動復
帰しないタイプのスイッチングレギュレータの回路構成
である。すなわち、負荷の短絡状態が解除されてもオペ
アンプ２の非反転入力端子には、上述のような電源を供
給する゛ルートがないため、電圧Ｖ＋は０の状態に保持
され、出力電圧制御用トランジスタ１はＯＦＦ状態を継
続する。そして゛出力電圧をＶに復帰させるには入力電
圧を一旦ＯＦＦして再びＯＮするようにする。なお、１
４．１５は安定したスイッチング動作を得るための正帰
還抵抗である。Next, FIG. 5 shows a circuit configuration of a switching regulator that does not automatically recover even if the load is released from the short circuit state. In other words, even if the short-circuited state of the load is released, the non-inverting input terminal of the operational amplifier 2 has no route for supplying power as described above, so the voltage V+ is held at 0, and the output voltage control transistor 1 continues the OFF state. Then, in order to restore the output voltage to V, the input voltage is turned off once and then turned on again. In addition, 1
4.15 is a positive feedback resistor for obtaining stable switching operation.
以上詳細に説明したよう、に、この発明に係る短絡保護
付電圧回路とすれば、負荷短絡を検出する新たな手段を
用いる必要がなく、基本性能である定電圧特性を実現す
る回路自身が負？ｔｉ短絡の検出機能を有しているので
、回路の簡素化が図れ、コストダウンはさることながら
動作信頼性が向上する。As explained in detail above, if the voltage circuit with short circuit protection according to the present invention is used, there is no need to use a new means for detecting a load short circuit, and the circuit itself that realizes the constant voltage characteristic, which is the basic performance, is ? Since it has a Ti short circuit detection function, it is possible to simplify the circuit, reduce costs, and improve operational reliability.
第１図はこの発明の一実施例を示す回路図、第２図は７
０９．７４１系で代表されるオペアンプの同相入力電圧
特性を示す図、第３図はこの発明で使用する４５５８系
で代表されるオペアンプの同相入力電圧特性を示す図、
第４図および第５図９−
はこの発明に係る短絡保護付電圧回路をスイッチングレ
ギュレータに適用した具体例を示すその回路図である。
１・・・・・・・・・出力電圧制御用トランジスタ２・
・・・・・・・・オペアンプ
■ａ・・・・・・転位電圧
特許出願人
立石電機株式会社
１０−
第１図
１
第２図
１乙…ｆ釘武： １ニア↑１）ｓＬ
”ｆ’ｓ随季１収菖
第３図
第４図Fig. 1 is a circuit diagram showing an embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
FIG. 3 is a diagram showing the common-mode input voltage characteristics of an operational amplifier represented by the 4558 series used in this invention,
FIGS. 4 and 5 are circuit diagrams showing specific examples in which the voltage circuit with short circuit protection according to the present invention is applied to a switching regulator. 1...... Output voltage control transistor 2.
・・・・・・Operational amplifier ■a・・・Transposition voltage patent applicant Tateishi Electric Co., Ltd. 10- Fig. 1 1 Fig. 2 1 O...f Kugitake: 1 near ↑ 1) sL
``f's season 1 collection iris figure 3 figure 4
Claims (1)
制御用トランジスタの出力を平滑する平滑回路と、一方
の入力端子に基準電圧が、他方の入力端子に上記平滑四
路の出、力側の電圧がそれぞれ印加され、上記出力電圧
制御用トランジスタを制御するオペアンプとを備えた定
電圧回路において、上記オペアンプは、特定の入力電圧
を境にその出力レベルが急激に反転する転位電圧を有し
た同相入力電圧特性のものからなり、負荷短絡時に該オ
ペアンプの出力レベルが急激に反転し、上記出力電圧制
御用トランジスタをＯＦＦさせるようにしたことを特徴
とする短絡保護付定電圧回路。(1) An output voltage control transistor, a smoothing circuit that smoothes the output of this output voltage control transistor, one input terminal receives the reference voltage, and the other input terminal receives the output voltage of the four smoothing circuits. is applied to each, and an operational amplifier that controls the output voltage control transistor, the operational amplifier has a common-mode input having a transition voltage whose output level rapidly reverses at a specific input voltage. 1. A constant voltage circuit with short-circuit protection, characterized in that the output level of the operational amplifier is rapidly reversed when a load short-circuits, and the output voltage control transistor is turned off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56148145A JPS5850020A (en) | 1981-09-19 | 1981-09-19 | Constant voltage circuit protected from short-circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56148145A JPS5850020A (en) | 1981-09-19 | 1981-09-19 | Constant voltage circuit protected from short-circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5850020A true JPS5850020A (en) | 1983-03-24 |
Family
ID=15446267
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56148145A Pending JPS5850020A (en) | 1981-09-19 | 1981-09-19 | Constant voltage circuit protected from short-circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5850020A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6395721A (en) * | 1986-10-13 | 1988-04-26 | Mitsubishi Electric Corp | Protection circuit for load switching device |
| JPH0553664A (en) * | 1991-08-27 | 1993-03-05 | Sanyo Electric Co Ltd | Constant voltage circuit |
-
1981
- 1981-09-19 JP JP56148145A patent/JPS5850020A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6395721A (en) * | 1986-10-13 | 1988-04-26 | Mitsubishi Electric Corp | Protection circuit for load switching device |
| JPH0553664A (en) * | 1991-08-27 | 1993-03-05 | Sanyo Electric Co Ltd | Constant voltage circuit |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DE4134537B4 (en) | Power supply circuit for a discharge lamp in a motor vehicle | |
| US7609498B2 (en) | Inverted circuit overcurrent protection device and hybrid integrated circuit device with the same incorporated | |
| DE2059687B2 (en) | Circuit arrangement for protecting an electric motor | |
| JPS5850020A (en) | Constant voltage circuit protected from short-circuit | |
| US4427902A (en) | Optimum transistor drive circuit with over load compensation | |
| JPH0475533B2 (en) | ||
| JPH01158515A (en) | Series voltage regulator | |
| JP3833805B2 (en) | Static isolator | |
| US4445160A (en) | Fault-powered low-level voltage clamp circuit | |
| JPS6378208A (en) | Dc power source | |
| JPH06276071A (en) | Overcurrent protecting circuit for transistor for electric power | |
| JPS5950712A (en) | Load shortcircuit protecting circuit | |
| JPH0756582Y2 (en) | Overcurrent detection circuit | |
| JPS6247367B2 (en) | ||
| JPS609220A (en) | Control circuit of switching element | |
| SU1741220A1 (en) | Push-pull power amplifier | |
| JPH0554729B2 (en) | ||
| JPH0526903Y2 (en) | ||
| JPH0441371Y2 (en) | ||
| JPS6129574B2 (en) | ||
| JPH0561557A (en) | Stabilized power source circuit | |
| JP3587056B2 (en) | Overvoltage protection circuit | |
| JPS5930581Y2 (en) | power protection circuit | |
| SU1156036A1 (en) | D.c.voltage stabilizer with short-circuit protection | |
| JPS6110336Y2 (en) |