JPH075935A - Power source parallel operation system - Google Patents

Power source parallel operation system

Info

Publication number
JPH075935A
JPH075935A JP5147969A JP14796993A JPH075935A JP H075935 A JPH075935 A JP H075935A JP 5147969 A JP5147969 A JP 5147969A JP 14796993 A JP14796993 A JP 14796993A JP H075935 A JPH075935 A JP H075935A
Authority
JP
Japan
Prior art keywords
power supply
voltage
output
fet
power source
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
Application number
JP5147969A
Other languages
Japanese (ja)
Other versions
JP2994174B2 (en
Inventor
Toshiyuki Zaitsu
俊行 財津
Kiyohiko Watanabe
清彦 渡辺
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
NEC Miyagi Ltd
Original Assignee
NEC Corp
NEC Miyagi Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp, NEC Miyagi Ltd filed Critical NEC Corp
Priority to JP5147969A priority Critical patent/JP2994174B2/en
Publication of JPH075935A publication Critical patent/JPH075935A/en
Application granted granted Critical
Publication of JP2994174B2 publication Critical patent/JP2994174B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Abstract

PURPOSE:To remarkably reduce power loss generated in the on/off control of a FET inserted as the one for reverse current prevention to a negative polarity output side and to quickly cope with the fault of a power source in the parallel operation of the power source to convert an input DC voltage to a desired output DC voltage by PWM. CONSTITUTION:In constitution to prevent reverse current from flowing by inserting the FET 6 to the output side of power source units 2-1, 2-2, a control voltage outputted from an output voltage control circuit 5 which controls an output voltage by the PWM of the power source units 2-1, 2-2 by the pulse width control of the PWM is detected, and the FET 6 can be turned on/off by a power source unit separation circuit 7.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は電源並列運転方式に関
し、特にパルス幅変調(PWM)を利用して入力直流電
圧を所定の出力直流電圧に変換出力し、かつ負極性の出
力側にFET(電界効果トランジスタ)を逆流阻止用素
子として介在させた複数の電源ユニットを並列運転する
電源並列運転方式に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply parallel operation system, and more particularly, it utilizes pulse width modulation (PWM) to convert an input DC voltage into a predetermined output DC voltage and outputs the same, and a FET ( Field-effect transistor) as a backflow prevention element, and a power source parallel operation system in which a plurality of power source units are operated in parallel.

【0002】[0002]

【従来の技術】高信頼性が要求される大容量の電源シス
テムにおいては、複数の電源ユニットの出力を並列接続
し、電源ユニットの一台が故障しても他の電源ユニット
には影響を与えず、安定した電力を負荷に供給してい
る。
2. Description of the Related Art In a large-capacity power supply system that requires high reliability, the outputs of a plurality of power supply units are connected in parallel, and even if one power supply unit fails, other power supply units are affected. Instead, it supplies stable power to the load.

【0003】このような並列運転においては、電源ユニ
ットの故障モードとして電源ユニット内部の出力コンデ
ンサが短絡したような場合には、当該電源ユニットを他
の正常な電源ユニットから分離することが必要である。
In such parallel operation, if the output capacitor inside the power supply unit is short-circuited as a failure mode of the power supply unit, it is necessary to separate the power supply unit from other normal power supply units. .

【0004】一般的には、このような分離のために出力
直流電圧の負極性側に他の電源ユニットからの出力電流
の逆流を抑止する接続としたダイオードを用いていた。
これは、ダイオードの逆方向阻止特性を利用したもので
ある。この場合、ダイオードの順電圧Vf によるロスが
発生する。
Generally, for such isolation, a diode connected to the negative side of the output DC voltage to prevent the reverse flow of the output current from another power supply unit has been used.
This utilizes the reverse blocking characteristic of the diode. In this case, a loss occurs due to the forward voltage V f of the diode.

【0005】また、最近では、ダイオードの代りにFE
Tを用いることも行なわれている。これは、オン抵抗が
ダイオードに比して小さいFETを用いればダイオード
よりもロスが小さいという利点を考慮したことによる。
このFET利用の場合も、何らかの方法で異常時にFE
Tをオフとしないと、正常な電源ユニットから電流が逆
流してしまうことになる。
Recently, FE has been used instead of the diode.
It is also practiced to use T. This is because the loss is smaller than that of a diode when an FET having a smaller on-resistance than a diode is used.
In the case of using this FET, the FE is also used when there is an abnormality in some way.
If T is not turned off, current will flow backward from a normal power supply unit.

【0006】図3は、従来の電源並列運転方式の構成図
である。図3の電源並列運転方式は、PWMによるDC
−DC変換で出力を得る2台の電源ユニット20−1と
20−2の並列運転例を示し、それぞれの電源ユニット
は入力直流電源1による入力直流電圧をPWMにより交
流変換する変換回路3と、変換回路3の出力を整流平滑
して所望の直流出力電圧として負荷8に供給する整流/
平滑回路4と、直流出力電圧を入力としてこれを一定に
保持するようにPWMのパルス幅を制御する制御信号S
を出力する出力電圧制御回路5と、逆流阻止用として負
荷性の出力側に挿入したダイオード21とを有する。
FIG. 3 is a block diagram of a conventional power source parallel operation system. The power supply parallel operation method of FIG.
An example of parallel operation of two power supply units 20-1 and 20-2 that obtain an output by DC conversion is shown. Each power supply unit is a conversion circuit 3 that converts the input DC voltage from the input DC power supply 1 into an AC by PWM, Rectification / smoothing of the output of the conversion circuit 3 and supply to the load 8 as a desired DC output voltage
A smoothing circuit 4 and a control signal S for inputting a DC output voltage and for controlling the PWM pulse width so as to hold the DC output voltage constant.
It has an output voltage control circuit 5 for outputting and a diode 21 inserted in the load side output side to prevent backflow.

【0007】[0007]

【発明が解決しようとする課題】上述した従来の電源並
列運転方式では、次のような問題点がある。
The conventional power supply parallel operation system described above has the following problems.

【0008】すなわち、負極性出力側にダイオードを挿
入する場合は、順電圧Vf が大きいため(0.5V〜1
V)発生するロスが大きく、電源の効率低下の原因とな
っている。例えば、5V/10A出力では、Vf =0.
5Vとするとロスは0.5V×10A=5Wとなりこれ
だけで効率が10%低下する。
That is, when a diode is inserted on the negative output side, the forward voltage V f is large (0.5 V to 1 V).
V) The generated loss is large, which causes a decrease in the efficiency of the power supply. For example, with 5 V / 10 A output, V f = 0.
At 5 V, the loss is 0.5 V × 10 A = 5 W, and this alone reduces the efficiency by 10%.

【0009】また、電源ユニットの負極性出力側にFE
Tを挿入する場合は、出力電流を検出してFETをオフ
とする方式(特開平3−103029号公告)や、出力
電圧を検出してFETをオフとする方式(特開昭63−
107460号公告)などが開示されているが、前者は
出力電流を検出しているため、ここでロスが発生し効率
が低下する。また後者は、出力電圧を検出してFETを
オフするため、検出電圧より僅かに大きい出力電圧程度
ではFETはそのままオンしており、他の電源ユニット
の出力電流が逆流してくることが避けられない。
Further, FE is provided on the negative output side of the power supply unit.
When T is inserted, a method of detecting the output current and turning off the FET (JP-A-3-103029) or a method of detecting the output voltage and turning off the FET (JP-A-63-63).
No. 107460) is disclosed, but since the former detects the output current, a loss occurs here and the efficiency decreases. In the latter case, the output voltage is detected and the FET is turned off. Therefore, when the output voltage is slightly higher than the detection voltage, the FET remains on and the output current of another power supply unit is prevented from flowing backward. Absent.

【0010】本発明の目的は上述した問題点を解決し、
電源ユニットの故障状態を検出するための検出ロスを著
しく抑圧し、かつ検出遅れによる他の電源ユニットから
の出力電流の逆流を根本的に抑止しうる電源並列運転方
式を提供することにある。
The object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a power supply parallel operation system capable of significantly suppressing a detection loss for detecting a failure state of a power supply unit and fundamentally suppressing a backflow of an output current from another power supply unit due to a detection delay.

【0011】[0011]

【課題を解決するための手段】本発明の方式は、入力直
流電圧にパルス幅変調を施して所定の出力直流電圧に変
換するとともに負極性の出力側にFETをオン状態で接
続して故障時には前記FETをオフとする電源ユニット
を複数並列運転する電源並列運転方式であって、前記出
力直流電圧の微小変動が所定のしきい値を超えるか否か
を検出し所定のしきい値を超える場合には遅滞なく前記
FETをオフとして当該電源ユニットを他のユニット電
源から分離する電源ユニット分離手段を備える。
According to the method of the present invention, a pulse width modulation is applied to an input DC voltage to convert it into a predetermined output DC voltage, and an FET on the negative output side is connected in an ON state to prevent a failure. A power supply parallel operation method in which a plurality of power supply units that turn off the FETs are operated in parallel, and it is detected whether or not a minute change in the output DC voltage exceeds a predetermined threshold value, and when the predetermined threshold value is exceeded. Is equipped with a power supply unit separation means for separating the power supply unit from other unit power supplies by turning off the FET without delay.

【0012】また本発明の方式は、前記出力直流電圧の
微小変動を、前記パルス幅変調による前記出力直流電圧
の規定値保持のためのパルス幅制御を行なう制御電圧に
よって検出するものとした構成を有する。
Further, the system of the present invention has a structure in which a minute fluctuation of the output DC voltage is detected by a control voltage for performing pulse width control for holding a specified value of the output DC voltage by the pulse width modulation. Have.

【0013】[0013]

【実施例】次に、本発明について図面を参照して説明す
る。図1は本発明の一実施例の構成図である。本実施例
は電源ユニット2−1,2−2の2台並列運転の場合を
例とし、電源ユニット2−1および2−2は同一構成
で、それぞれ入力値電源1と負荷8とに並列接続されて
いる。電源ユニット2−1を例としてその構成を見る
に、入力直流電源1による入力直流電圧にPWMを施し
て交流変換して結合トランスを介して出力する変換回路
3と、変換回路3の出力を整流し平滑化を施して所望の
出力直流電圧として負荷8に出力する整流/平滑回路4
と、整流/平滑回路4の出力を検出して、検出出力が所
定の規定値となるように、変換回路3におけるPWMの
パルス幅を制御するための所定の規定値と検出出力との
差の変動成分としての制御信号を出力する出力電圧制御
回路5と、電源ユニット2−1の負極性の出力側に挿入
したFET6と、本発明に直接かかわる電源ユニット分
離手段を構成する電源ユニット分離回路7とを備える。
DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. In this embodiment, two power source units 2-1 and 2-2 are operated in parallel. The power source units 2-1 and 2-2 have the same configuration and are connected in parallel to the input value power source 1 and the load 8, respectively. Has been done. The configuration of the power supply unit 2-1 will be taken as an example. A conversion circuit 3 that performs PWM on the input DC voltage from the input DC power supply 1 to convert it to AC and outputs it via a coupling transformer, and the output of the conversion circuit 3 are rectified. Rectifying / smoothing circuit 4 which performs smoothing and outputs a desired output DC voltage to the load 8.
And detecting the output of the rectifying / smoothing circuit 4, and determining the difference between the predetermined specified value for controlling the PWM pulse width in the conversion circuit 3 and the detected output so that the detected output has a predetermined specified value. An output voltage control circuit 5 for outputting a control signal as a fluctuation component, an FET 6 inserted in the negative output side of the power supply unit 2-1 and a power supply unit separation circuit 7 constituting a power supply unit separation means directly related to the present invention. With.

【0014】次に、本実施例の動作について図2を参照
して説明する。
Next, the operation of this embodiment will be described with reference to FIG.

【0015】図2は図1の電源ユニット分離回路7の部
分を詳細に示す構成図である。
FIG. 2 is a block diagram showing in detail the portion of the power supply unit separation circuit 7 of FIG.

【0016】図2において、電源ユニット分離回路7
は、電源ユニット分離回路7を電源ユニット2−1の本
体、すなわちPWMによる出力直流電圧発生回路から電
気的には分離して光学的に制御信号を抽出するホトカプ
ラ9aおよび9bと、一定レベル以上の制御信号の変動
を増幅して出力するIC構成のシャントレギュレータ1
3と、シャントレギュレータ13の動作に応動してオン
/オフしFET8のオン/オフを制御するトランジスタ
16ならびに関連抵抗10,11,12,14,15,
17および18を含む。
In FIG. 2, the power supply unit separation circuit 7
Is a photocoupler 9a and 9b that electrically separates the power supply unit separation circuit 7 from the main body of the power supply unit 2-1, that is, an output DC voltage generation circuit by PWM, and optically extracts a control signal. A shunt regulator with an IC configuration that amplifies and outputs fluctuations in control signals
3 and a transistor 16 that turns on / off in response to the operation of the shunt regulator 13 to control on / off of the FET 8 and associated resistors 10, 11, 12, 14, 15,
Includes 17 and 18.

【0017】次に、電源ユニット分離回路7の動作につ
いて説明する。
Next, the operation of the power supply unit separation circuit 7 will be described.

【0018】いま、整流/平滑回路4の出力が例えば5
Vであるとする。定常状態ではシャントレギュレータ1
3の出力は2.5Vと設定される。シャントレギュレー
タ13は、抵抗10および11により分圧された出力5
Vの分圧電圧を受け、この分圧電圧が許容変動範囲を含
む所定の一定値にあるときは出力を基準値としての2.
5Vに設定し、何等かの理由で所定の一定値を超える変
動を生ずるとその変動成分の絶対値を増幅して基準値
2.5Vに重畳する。正常状態にあっては、トランジス
タ16はシャントレギュレータ13による電圧設定でオ
ンとされ、これによってFET6もオン状態に設定され
る。
Now, the output of the rectifying / smoothing circuit 4 is, for example, 5
Suppose that it is V. Shunt regulator 1 in steady state
The output of 3 is set to 2.5V. The shunt regulator 13 outputs the output 5 divided by the resistors 10 and 11.
When the divided voltage of V is received and the divided voltage is within a predetermined constant value including the allowable fluctuation range, the output is set as a reference value.
When the fluctuation is set to 5V and exceeds a predetermined constant value for some reason, the absolute value of the fluctuation component is amplified and superposed on the reference value 2.5V. In the normal state, the transistor 16 is turned on by the voltage setting by the shunt regulator 13, and thereby the FET 6 is also turned on.

【0019】電源ユニット2−1内で障害が発生し、例
えば整流/平滑回路4が出力コンデンサなどのショート
モードで破壊し、直流出力電圧が所定の一定値を超えて
微小低下するとシャントレギュレータ13で変動分を絶
対値増幅し、出力設定値を2.5Vから大きく上昇させ
る。シャントレギュレータ13の増幅度を仮に100と
すると、出力電圧が30m微小低下すればシャントレギ
ュレータ13の出力値は2.5Vに3V重畳され、これ
によってトランジスタ16がオフとなり、FET6もオ
フに制御される。
If a failure occurs in the power supply unit 2-1, the rectifying / smoothing circuit 4 is destroyed in a short mode such as an output capacitor, and the DC output voltage drops slightly below a predetermined constant value, the shunt regulator 13 is used. The variation is amplified in absolute value, and the output set value is greatly increased from 2.5V. Assuming that the amplification degree of the shunt regulator 13 is 100, if the output voltage slightly drops by 30 m, the output value of the shunt regulator 13 is superposed on 2.5 V by 3 V, whereby the transistor 16 is turned off and the FET 6 is also controlled to be turned off. .

【0020】このようにして、電源ユニット分離回路7
は、FET6を定常時はオンとして低ロスで電力を負荷
7に供給させ、異常時には直流出力電圧の微小変化を検
出してFET6をオフとして負荷7との分離を行なう。
この電源ユニット分離回路7がFET6をオフとする直
流出力の微小変動量はあらかじめ設定されるが、上述の
例の如く少なくとも数10mVに達すれば発動され、こ
れにより電源ユニットの異常に対応して極めて低ロスで
遅滞なくFET6をオフとすることができる。
In this way, the power supply unit separation circuit 7
In the steady state, the FET 6 is turned on to supply electric power to the load 7 with a low loss, and when abnormal, a minute change in the DC output voltage is detected and the FET 6 is turned off to separate from the load 7.
The minute fluctuation amount of the direct current output for turning off the FET 6 by the power supply unit separation circuit 7 is set in advance, but it is activated when it reaches at least several tens of mV as in the above-mentioned example, so that the power supply unit becomes extremely responsive to the abnormality. With low loss, the FET 6 can be turned off without delay.

【0021】なお、図3に示す如く、FETの並列構成
がダイオードによる並列構成よりも低ロスとして扱える
範囲は、図3におけるFET特性101とダイオード特
性102の関係からも明らかな如く、出力電流がIma
xよりも小さい領域である。
As shown in FIG. 3, the range in which the parallel configuration of the FETs can be treated as a lower loss than the parallel configuration of the diodes is as shown in the relationship between the FET characteristic 101 and the diode characteristic 102 in FIG. Ima
It is an area smaller than x.

【0022】また、本実施例においては、電源ユニット
が2台の場合を例としたが、3台以上の場合も同様に実
施しうることは明らかである。
Further, in the present embodiment, the case where the number of power supply units is two is taken as an example, but it is clear that the case where the number of power supply units is three or more can be similarly applied.

【0023】[0023]

【発明の効果】以上説明したように本発明は、PWMに
より入力直流電圧から所望の出力直流電圧を得る電源ユ
ニットの出力電圧制御に利用する制御信号を流用して電
源ユニットの負極性の出力側に挿入した逆流抑止用のF
ETをオン/オフ制御することにより、電源ユニット内
のショート等の故障に対して迅速に応動しかつ著しい低
ロス化を図った電源並列運転を可能とする効果を有す
る。
As described above, according to the present invention, the control signal used for the output voltage control of the power supply unit for obtaining the desired output DC voltage from the input DC voltage by PWM is diverted to use the negative output side of the power supply unit. F for backflow prevention inserted in
By controlling the ET on / off, it is possible to quickly respond to a failure such as a short circuit in the power supply unit and to enable parallel operation of the power supplies with significantly reduced loss.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の一実施例の電源並列運転方式の構成図
である。
FIG. 1 is a configuration diagram of a power supply parallel operation system according to an embodiment of the present invention.

【図2】図1の電源ユニット分離回路8の部分を詳細に
示す構成図である。
FIG. 2 is a configuration diagram showing in detail a portion of a power supply unit separation circuit 8 of FIG.

【図3】従来の電源並列運転方式の構成図である。FIG. 3 is a configuration diagram of a conventional power source parallel operation system.

【図4】ダイオードとFETの電圧対電流特性図であ
る。
FIG. 4 is a voltage-current characteristic diagram of a diode and a FET.

【符号の説明】[Explanation of symbols]

1 入力直流電源 2−1,2−2 電源ユニット 3 変換回路 4 整流/平滑回路 5 出力電圧制御回路 6 FET 7 電源ユニット分離回路 8 負荷 9a,9b ホトカプラ 10〜12 抵抗 13 シャントレギュレータ 14,15 抵抗 16 トランジスタ 17,18 抵抗 1 Input DC power supply 2-1 and 2-2 power supply unit 3 conversion circuit 4 rectification / smoothing circuit 5 output voltage control circuit 6 FET 7 power supply unit separation circuit 8 load 9a, 9b photo coupler 10-12 resistance 13 shunt regulator 14, 15 resistance 16 transistors 17 and 18 resistors

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 入力直流電圧にパルス幅変調を施して所
定の出力直流電圧に変換するとともに負極性の出力側に
FETをオン状態で接続して故障時には前記FETをオ
フとする電源ユニットを複数並列運転する電源並列運転
方式であって、前記出力直流電圧の微小変動が所定のし
きい値を超えるか否かを検出し所定のしきい値を超える
場合には遅滞なく前記FETをオフとして当該電源ユニ
ットを他のユニット電源から分離する電源ユニット分離
手段を備えることを特徴とする電源並列運転方式。
1. A plurality of power supply units for converting an input DC voltage into a predetermined output DC voltage by performing pulse width modulation and connecting an FET to a negative output side in an ON state to turn off the FET when a failure occurs. It is a power supply parallel operation system that operates in parallel, and detects whether or not a minute change in the output DC voltage exceeds a predetermined threshold value, and when it exceeds a predetermined threshold value, turns off the FET without delay and A power supply parallel operation system comprising a power supply unit separating means for separating the power supply unit from other unit power supplies.
【請求項2】 前記出力直流電圧の微小変動を、前記パ
ルス幅変調による前記出力直流電圧の規定値保持のため
のパルス幅制御を行なう制御電圧によって検出すること
を特徴とする請求項1記載の電源並列運転方式。
2. The minute fluctuation of the output DC voltage is detected by a control voltage for performing pulse width control for holding a specified value of the output DC voltage by the pulse width modulation. Power supply parallel operation method.
JP5147969A 1993-06-18 1993-06-18 Power supply parallel operation method Expired - Fee Related JP2994174B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5147969A JP2994174B2 (en) 1993-06-18 1993-06-18 Power supply parallel operation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5147969A JP2994174B2 (en) 1993-06-18 1993-06-18 Power supply parallel operation method

Publications (2)

Publication Number Publication Date
JPH075935A true JPH075935A (en) 1995-01-10
JP2994174B2 JP2994174B2 (en) 1999-12-27

Family

ID=15442199

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5147969A Expired - Fee Related JP2994174B2 (en) 1993-06-18 1993-06-18 Power supply parallel operation method

Country Status (1)

Country Link
JP (1) JP2994174B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1146620A2 (en) * 2000-03-30 2001-10-17 Hitachi, Ltd. Driving method of semiconductor switching device and power supply apparatus operated according to said method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60154058A (en) * 1984-01-23 1985-08-13 三井化学株式会社 Polymer composite metal vibration-damping material

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60154058A (en) * 1984-01-23 1985-08-13 三井化学株式会社 Polymer composite metal vibration-damping material

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1146620A2 (en) * 2000-03-30 2001-10-17 Hitachi, Ltd. Driving method of semiconductor switching device and power supply apparatus operated according to said method
EP1146620A3 (en) * 2000-03-30 2001-10-24 Hitachi, Ltd. Driving method of semiconductor switching device and power supply apparatus operated according to said method
US6381152B1 (en) 2000-03-30 2002-04-30 Hitachi, Ltd. Method of driving semiconductor switching device in non-saturated state and power supply apparatus containing such a switching device

Also Published As

Publication number Publication date
JP2994174B2 (en) 1999-12-27

Similar Documents

Publication Publication Date Title
US5347164A (en) Uninterruptible power supply having a 115V or 230V selectable AC output and power saving
US5821730A (en) Low cost battery sensing technique
JP2751962B2 (en) Switching power supply
JP2571942Y2 (en) Boost converter
JPH06343262A (en) Synchronously rectifying converter
JPH075935A (en) Power source parallel operation system
EP0900469B1 (en) Switched-mode power supply arrangement
JPS61244271A (en) Switching regulator
JP2850274B2 (en) Switching power supply
JP3897251B2 (en) Current balance control circuit for power supply
JP3259611B2 (en) DC power supply system
JP2803151B2 (en) Power supply
US6204571B1 (en) Multiple power supply unit with improved overcurrent sensitivity
JPH11164549A (en) Dc-dc converter
JPH1118415A (en) Current balance circuit of parallel operation power unit
JP2555686Y2 (en) Switching power supply
JP2846679B2 (en) Parallel redundant operation of power supply units
JPS6111778Y2 (en)
JPH06121534A (en) Parallel operation system for dc power supply
JPH0116351Y2 (en)
JP2855759B2 (en) Parallel operation power supply control circuit
JPH0612951B2 (en) Power supply
JP3501972B2 (en) Power system
JP2600711B2 (en) Non-control output voltage stabilization circuit in cross regulation
JPH08126315A (en) Overcurrent protection circuit for power source

Legal Events

Date Code Title Description
A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 19960402

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20071022

Year of fee payment: 8

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20081022

Year of fee payment: 9

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20091022

Year of fee payment: 10

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20091022

Year of fee payment: 10

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20101022

Year of fee payment: 11

LAPS Cancellation because of no payment of annual fees