JP3400216B2 - Power supply - Google Patents
Power supplyInfo
- Publication number
- JP3400216B2 JP3400216B2 JP30565095A JP30565095A JP3400216B2 JP 3400216 B2 JP3400216 B2 JP 3400216B2 JP 30565095 A JP30565095 A JP 30565095A JP 30565095 A JP30565095 A JP 30565095A JP 3400216 B2 JP3400216 B2 JP 3400216B2
- Authority
- JP
- Japan
- Prior art keywords
- power supply
- overcurrent
- current
- circuit
- voltage
- 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 - Lifetime
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- Measurement Of Current Or Voltage (AREA)
- Continuous-Control Power Sources That Use Transistors (AREA)
- Dc-Dc Converters (AREA)
- Inverter Devices (AREA)
Description
【0001】[0001]
【発明の属する技術分野】本発明は、過電流検出回路を
用いる電源装置に関する。The present invention relates to relates to a power supply apparatus using <br/> overcurrent detection circuitry.
【0002】[0002]
【従来の技術】過電流検出回路は過負荷状態が発生した
際、その状態を検知し電源装置を停止し、負荷を遮断
し、あるいは電流/電圧を制限し、電源装置及び/又は
負荷装置を保護するために使用される。従来の過電流検
出回路では、負荷回路へ流れる電流の大きさを検出する
ために負荷電流が流れる電流検出用抵抗を設け、該抵抗
に発生する電圧降下(負荷電流に比例する電圧)とトラ
ンジスタのベ−ス・エミッタ間順方向電圧を比較し、負
荷電流が過大になれば、この電圧降下が大きくなるので
当該トランジスタが作動(導通)し、電源の停止,負荷
の遮断あるいは電源又は負荷の過電流抑制のための信号
を発生するようになっていた。この場合、周囲温度の変
化によりトランジスタのベ−ス・エミッタ間順方向電圧
が変化するため、当該トランジスタの作動点(過電流検
出点)が変化するので、正確な過電流検出閾値を設定す
ることは困難であった。2. Description of the Related Art When an overload condition occurs, an overcurrent detection circuit detects the condition and stops the power supply device, shuts off the load, or limits the current / voltage to prevent the power supply device and / or the load device. Used to protect. In the conventional overcurrent detection circuit, a current detection resistor through which the load current flows is provided to detect the magnitude of the current flowing into the load circuit, and a voltage drop (voltage proportional to the load current) generated in the resistor and a transistor The forward voltage between the base and the emitter is compared, and if the load current becomes excessive, this voltage drop becomes large, and the transistor in question operates (conducts), stopping the power supply, shutting off the load, or overloading the power supply or load. It was designed to generate a signal for current suppression. In this case, since the base-emitter forward voltage of the transistor changes due to changes in ambient temperature, the operating point (overcurrent detection point) of the transistor changes, so set an accurate overcurrent detection threshold value. Was difficult.
【0003】そこで過電流検出回路の周囲温度変化によ
る誤作動を低減するため、例えば、実開平4−6977
0号公報においては、下記のような手段が取られてい
る。当該過電流検出回路の構成を図4に示す。図4にお
いて、電源装置1からの出力電圧V1は電流検出用抵抗
器2を通り負荷装置3に接続されている。負荷への電流
は電流検出用抵抗器2で電圧降下を起こし負荷装置3の
入力電圧はV2となる。Therefore, in order to reduce malfunctions of the overcurrent detection circuit due to changes in the ambient temperature, for example, the actual open flat wire 4-6977 is used.
In JP-A-0, the following measures are taken. The configuration of the overcurrent detection circuit shown in FIG. In FIG. 4 , the output voltage V1 from the power supply device 1 is connected to the load device 3 through the current detecting resistor 2. The current to the load causes a voltage drop in the current detecting resistor 2 and the input voltage of the load device 3 becomes V 2 .
【0004】電源出力電圧V1を抵抗4,5で分圧し、
エミッタバイアス電圧V3を得、又、電圧V2を抵抗6,
7で分圧しベ−スバイアス電圧V4を得る。V3とV4の
電圧差をトランジスタ8のエミッタ・ベ−ス間順方向電
圧と比較し、電圧差が大きくなった時に過電流発生と判
定してコレクタ電流を流し(過電流検出信号)、電源装
置1を停止するように動作する。この装置において、V
3,V4の電圧差は任意に決定可能なため、検出精度を向
上させる効果があり、また周囲温度変化により変化する
トランジスタ8のエミッタ・ベ−ス間順方向電圧を、エ
ミッタに接続されているダイオ−ド9の温度特性により
補正している。つまり、周囲温度変化によるトランジス
タ8の特性変化をダイオ−ド9の温度特性で相殺する様
にエミッタバイアス電圧が変化するので、周囲温度が変
化しても誤動作しにくい。The power supply output voltage V 1 is divided by resistors 4 and 5,
The emitter bias voltage V 3 is obtained, and the voltage V 2 is applied to the resistors 6 and 6.
The voltage is divided by 7 to obtain the base bias voltage V 4 . The voltage difference between V 3 and V 4 is compared with the forward voltage between the emitter and the base of the transistor 8, and when the voltage difference becomes large, it is determined that an overcurrent has occurred and a collector current is passed (overcurrent detection signal). It operates so as to stop the power supply device 1. In this device, V
3, the voltage difference V 4 because any decidable, has the effect of improving the detection accuracy, the emitter-base of the transistor 8 which changes depending on the ambient temperature change - the scan forward voltage, connected to the emitter The temperature characteristics of the diode 9 are corrected. That is, since the emitter bias voltage changes so that the temperature characteristic of the diode 9 cancels the characteristic change of the transistor 8 due to the ambient temperature change, malfunction does not easily occur even if the ambient temperature changes.
【0005】図5に、図4に示す過電流検出回路を組込
んだ電源装置の一例を示す。DC/DCコンバ−タを構
成するトランス25の1次巻線に接続されたMOS−F
ET24を、制御IC44が、繰返しON/OFFして
1次電流をチョッピングする。[0005] FIG. 5 shows an example of incorporating power supply overcurrent detection circuit shown in FIG. MOS-F connected to the primary winding of the transformer 25 which constitutes a DC / DC converter
The control IC 44 repeatedly turns ON / OFF the ET 24 to chop the primary current.
【0006】これにより出力電圧Vo1,Vo2が発生
する。制御IC44は、その電源電圧端(コンデンサ2
3の正極)の電圧が零レベルから所定レベル以上に立上
るときに内部回路がリセット(電源オン・リセット)さ
れて、上述のMOS−FET24の繰返しON/OFF
を開始し、フォトカプラ41のフォトトランジスタが導
通(ON)して負電位(コンデンサ23の負極電位)に
なるとこれに応答してMOS−FET24をOFFとし
てON/OFFを停止し、再度電源オン・リセットがか
かるまでOFFを維持する。As a result, output voltages Vo1 and Vo2 are generated. The control IC 44 has its power supply voltage end (capacitor 2
When the voltage of the positive electrode 3) rises from the zero level to a predetermined level or more, the internal circuit is reset (power on / reset), and the above-mentioned MOS-FET 24 is repeatedly turned on / off.
When the phototransistor of the photocoupler 41 becomes conductive (ON) and becomes a negative potential (negative potential of the capacitor 23), the MOS-FET 24 is turned off in response to this, the ON / OFF is stopped, and the power is turned on again. It stays off until it is reset.
【0007】負荷に過電流が発生した時には上述のよう
に電流検出用トランジスタ8が作動(導通:ON)し、
続いて該トランジスタ8に接続された電流増幅用トラン
ジスタ40が導通(ON)して、フォトカプラ41の発
光ダイオ−ドが通電されて発光し、該フォトカプラ41
のフォトトランジスタが導通(ON)する。これに応答
して制御IC44が、MOS−FET24をOFFとし
てON/OFFを停止し、再度電源オン・リセットがか
かるまでOFFを維持する。すなわち、制御用IC44
を停止させることにより、チョッパ用MOS−FET2
4を停止させて2次交流出力(変圧トランス25出力)
を零とし、従って2次直流出力(Vo1,Vo2)も零
となる。When an overcurrent occurs in the load, the current detection transistor 8 operates (conduction: ON) as described above,
Then, the current amplification transistor 40 connected to the transistor 8 is turned on (ON), the light emitting diode of the photocoupler 41 is energized to emit light, and the photocoupler 41 is turned on.
The phototransistor of turns on. In response to this, the control IC 44 turns off the MOS-FET 24 to stop the on / off, and keeps the off until the power is turned on / reset again. That is, the control IC 44
MOS-FET2 for chopper by stopping
4 is stopped and secondary AC output (transformer transformer 25 output)
Is zero, and therefore the secondary DC output (Vo1, Vo2) is also zero.
【0008】[0008]
【発明が解決しようとする課題】前述の電源装置(図
5)においては、急峻な出力短絡時や、特に出力短絡起
動時などの場合には、前記増幅回路(40,41,4
5)が使用する電圧を過電流検出回路20が監視する電
源出力ライン(Vo1)から得ている為、回路20の過
電流保護動作(トランジスタ8のON)前に該電圧が低
下すると、増幅回路(40,41,45)が動作しない
(トランジスタ40がONしない)という問題がある。[SUMMARY OF THE INVENTION] The foregoing power supplies (Figure
In 5 ), when the output is short-circuited suddenly, or particularly when the output is short-circuited, the amplifier circuit (40, 41, 4) is used.
Since the voltage used in 5) is obtained from the power supply output line (Vo1) monitored by the overcurrent detection circuit 20, if the voltage drops before the overcurrent protection operation of the circuit 20 (ON of the transistor 8), the amplifier circuit There is a problem that (40, 41, 45) does not operate (transistor 40 does not turn on).
【0009】本発明は、過電流保護機能が高い電源装置
を提供することを目的とする。[0009] The present invention is directed to purpose an overcurrent protection function to provide a high power device.
【0010】[0010]
【課題を解決するための手段】本発明の電源装置の第1
態様(図1,図2)は、交流電流を直流に変換する整流
ブリッジ(22),トランス(25),該トランスの1次コイル
と前記整流ブリッジ(22)の間の通電ル−プに介挿された
スイッチング手段(24)、および、過電流検出信号に応答
して該スイッチング手段で前記通電ル−プをオフにする
制御手段(44)を含む電源回路(1);該電源回路の出力電
流が流れる抵抗器(2)を含み該抵抗器の前記電源回路側
の電位と負荷側の電位との電位差に基づき過電流を検出
して過電流信号を発生する過電流検出回路(20);およ
び、過電流信号を増幅した過電流検出信号を前記制御手
段(44)に与える増幅手段(40,41,45);を備える電源装置
において、前記増幅手段(40,41,45)の電源電圧印加端に
は、前記過電流検出回路(20)が監視する電力出力ライン
(Vo1)とは別の、所要電圧を与えるライン(Vo2)に接続し
たことを特徴とする。The first power supply device of the present invention, in order to solve the problems]
The mode (FIGS. 1 and 2 ) is such that a rectifying bridge (22) for converting an alternating current into a direct current, a transformer (25), and a conduction loop between the primary coil of the transformer and the rectifying bridge (22). Power supply circuit (1) including inserted switching means (24) and control means (44) for turning off the energization loop by the switching means in response to an overcurrent detection signal; output of the power supply circuit An overcurrent detection circuit (20) that includes a resistor (2) through which a current flows and that detects an overcurrent based on the potential difference between the power supply circuit side potential and the load side potential of the resistor, and generates an overcurrent signal; And a power supply device comprising amplification means (40, 41, 45) for giving an overcurrent detection signal obtained by amplifying an overcurrent signal to the control means (44), wherein the power supply voltage of the amplification means (40, 41, 45) The power output line monitored by the overcurrent detection circuit (20)
It is characterized in that it is connected to a line (Vo2) that gives a required voltage, which is different from (Vo1).
【0011】更に本発明の第2態様の電源装置(図3)
は、交流電流を直流に変換する整流ブリッジ(22),トラ
ンス(25),該トランスの1次コイルと前記整流ブリッジ
(22)の間の通電ル−プに介挿されたスイッチング手段(2
4),過電流検出信号に応答して該スイッチング手段で前
記通電ル−プをオフにする制御手段(44),トランスの2
次巻線に接続した整流器(26,27),その整流出力を平滑
化するためのチョ−クコイル(30),アノ−ドが該チョ−
クコイルの該整流器側に接続されたダイオ−ド(44)、お
よび、該ダイオ−ドのカソ−ドと前記チョ−クコイルの
他方側に接続されたコンデンサ(47)を含む電源回路
(1);該電源回路の出力電流が流れる抵抗器(2)を含み該
抵抗器の前記電源回路側の電位と負荷側の電位との電位
差に基づき過電流を検出して過電流信号を発生する過電
流検出回路(20);および、前記過電流信号を増幅した過
電流検出信号を前記制御手段(44)に与える増幅手段であ
って、その電源電圧印加端が前記ダイオ−ド(44)のカソ
−ドに接続された増幅手段(40,41,45);を備える。Further, the power supply device according to the second aspect of the present invention (FIG. 3 )
Is a rectifying bridge (22) for converting an alternating current into a direct current, a transformer (25), a primary coil of the transformer and the rectifying bridge.
Switching means (2) inserted in the energizing loop between (22)
4), control means (44) for turning off the energization loop by the switching means in response to the overcurrent detection signal, and transformer 2
The rectifier (26, 27) connected to the next winding, the choke coil (30) for smoothing the rectified output, and the anode are the choke.
Power supply circuit including a diode (44) connected to the rectifier side of the coil coil, and a capacitor (47) connected to the cathode of the diode and the other side of the choke coil.
(1); Includes a resistor (2) through which an output current of the power supply circuit flows, and detects an overcurrent based on a potential difference between the power supply circuit side potential and the load side potential of the resistor to generate an overcurrent signal An overcurrent detection circuit (20) for amplifying the overcurrent signal, and an amplification means for giving an overcurrent detection signal obtained by amplifying the overcurrent signal to the control means (44), the power supply voltage application terminal of which is the diode (44). Amplification means (40, 41, 45) connected to the cathode.
【0012】なお、理解を容易にするためにカッコ内に
は、図面に示し後述する実施例の対応要素又は対応事項
の符号を、参考までに付記した。In order to facilitate understanding, the reference numerals of the corresponding elements or corresponding matters of the embodiments shown in the drawings and described later are added in parentheses for reference.
【0013】[0013]
【発明の実施の形態】本発明の電源装置の過電流検出回
路(20)は、電流検出用抵抗器(2)と電流検出用トランジ
スタ(8)と、そのトランジスタ(8)のベース・エミッタ間
順方向電圧の温度変化をダイオードの順方向電圧の温度
変化で相殺するバイアス手段(9)と、電流検出設定手段
(4,5)を備える。また、増幅手段は、増幅用トランジス
タ(40),サイリスタ(48)又はトライアックを含む。BEST MODE FOR CARRYING OUT THE INVENTION An overcurrent detection circuit (20) for a power supply device of the present invention comprises a current detection resistor (2), a current detection transistor (8), and a base-emitter of the transistor (8). Bias means (9) for canceling forward voltage temperature change by diode forward voltage temperature change, and current detection setting means
Equipped with (4,5). Further, the amplification means includes an amplification transistor (40), a thyristor (48) or a triac.
【0014】本発明の他の目的および特徴は、図面を参
照した以下の実施例の説明より明らかになろう。Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.
【0015】[0015]
【実施例】−第1実施例−
図1に、本発明の電源回路の一実施例を示す。図1にお
いて交流電源21を整流用ダイオ−ドブリッジ22にて
整流し、平滑用コンデンサ23にて平滑して直流(第1
次)に変換する。この直流(第1次)の出力回路にはM
OS−FET24と変圧用トランス25の1次側が直列
に接続されている。MOS−FET24は制御用IC4
4により繰返しON/OFF駆動される。制御用IC4
4は、図5に示す従来例に用いられているものと同じ機
能のものである。MOS−FET24の繰返しのON/
OFFにより、トランス25の二次側の1つのコイルに
交流電圧(第2次の交流)が発生する。この交流をダイ
オ−ド26,27が直流(第2次)に変換しチョ−クコ
イル30およびコンデンサ32が、脈動直流を定レベル
に平滑化する。この定レベル直流が抵抗器2を介して、
更にコンデンサ42で平滑されて出力される。これが第
1の出力回路である。この回路の直流出力電圧Vo1
は、電圧検出回路43にてレベルをモニタされている。
電圧検出回路43は、検出電圧Vo1を示すフィ−ドバ
ック信号を制御IC44に与え、制御IC44は、検出
電圧Vo1が設定値(目標値)に合致するように、MO
S−FET24のONデュ−ティを調整する。Embodiments- First Embodiment-FIG. 1 shows an embodiment of a power supply circuit according to the present invention. In FIG. 1 , an AC power source 21 is rectified by a rectifying diode bridge 22 and smoothed by a smoothing capacitor 23 to generate a direct current (first
To the next). This direct current (first order) output circuit has M
The OS-FET 24 and the primary side of the transformer 25 for transformation are connected in series. The MOS-FET 24 is a control IC 4
4 is repeatedly turned ON / OFF. Control IC4
4 is of the same functions as those used in the conventional example shown in FIG. Repeated ON / OFF of MOS-FET24
When turned off, an AC voltage (secondary AC) is generated in one coil on the secondary side of the transformer 25. The alternating current is converted into direct current (secondary) by the diodes 26 and 27, and the choke coil 30 and the capacitor 32 smooth the pulsating direct current to a constant level. This constant level direct current is passed through the resistor 2
Further, the output is smoothed by the capacitor 42. This is the first output circuit. DC output voltage Vo1 of this circuit
Is monitored by the voltage detection circuit 43.
The voltage detection circuit 43 gives a feedback signal indicating the detection voltage Vo1 to the control IC 44, and the control IC 44 sets the MO so that the detection voltage Vo1 matches the set value (target value).
The ON duty of the S-FET 24 is adjusted.
【0016】トランス25の二次側のもう1つのコイル
にも交流電圧(第2次の交流)が発生する。この交流を
ダイオ−ド28,29が直流(第2次)に変換しチョ−
クコイル31およびコンデンサ33が、脈動直流を定レ
ベルに平滑化する。この定レベル直流が出力される。こ
れが第2の出力回路50である。An AC voltage (secondary AC) is also generated in the other coil on the secondary side of the transformer 25. This alternating current is converted into direct current (secondary) by the diodes 28 and 29, and the cho
The coil 31 and the capacitor 33 smooth the pulsating direct current to a constant level. This constant level DC is output. This is the second output circuit 50.
【0017】この実施例では、第1の出力回路に過電流
検出回路20が接続されている。この過電流検出回路2
0の電流検出用トランジスタ8の出力は、電流増幅用ト
ランジスタ40のベ−スに印加される。コンデンサ45
は平滑用のものである。電流増幅用トランジスタ40の
コレクタは、フォトカプラ41の発光ダイオ−ドを経由
して、別系統の第2の出力回路50から電圧(Vcc)
を得ている。In this embodiment, the overcurrent detection circuit 20 is connected to the first output circuit. This overcurrent detection circuit 2
The output of the current detection transistor 8 of 0 is applied to the base of the current amplification transistor 40. Capacitor 45
Is for smoothing. The collector of the current amplifying transistor 40 is supplied with a voltage (Vcc) from the second output circuit 50 of another system via the light emitting diode of the photocoupler 41.
Is getting
【0018】正常動作中は、電流検出用トランジスタ8
はOFFであり、従って電流増幅用トランジスタ40も
OFFで、フォトカプラ41の発光ダイオ−ドは発光せ
ず、フォトトランジスタがOFFで、制御IC44には
負電位(機器ア−ス)は与えられない。During normal operation, the current detection transistor 8
Is OFF, therefore the current amplification transistor 40 is also OFF, the light emitting diode of the photocoupler 41 does not emit light, the phototransistor is OFF, and a negative potential (device ground) is not applied to the control IC 44. .
【0019】しかし過電流,負荷短絡あるいは短絡起動
が発生すると、電流検出用トランジスタ8がONし、別
系統ライン(50の出力ライン)に接続されている電流
増幅用トランジスタ40がONし、フォトカプラ41の
発光ダイオ−ドが発光してフォトトランジスタがONし
て、制御IC44に負電位(機器ア−ス)が、フォトカ
プラ41から与えられる。制御IC44はこれに応答し
てMOS−FET24をOFFとし、ON/OFFを停
止する。電源電圧(コンデンサ23の正極電圧)が、0
から所定レベル以上に立上って電源オン・リセットが働
くまで、制御IC44は、MOS−FET24のOFF
を継続する。したがってMOS−FET24による直流
チョッパ動作が停止し、トランス25の2次側の交流出
力(第2次)が無くなり、直流(2次)出力も無くなる
ので出力停止となる。なお、制御用IC44自身の電源
は第1次直流から得ているので、過電流等が発生した場
合でも制御機能が損なわれることはない。However, when an overcurrent, a load short circuit or a short circuit start occurs, the current detection transistor 8 is turned on, the current amplification transistor 40 connected to another system line (50 output line) is turned on, and the photocoupler is turned on. The light emitting diode of 41 emits light to turn on the phototransistor, and a negative potential (apparatus ground) is applied to the control IC 44 from the photocoupler 41. In response to this, the control IC 44 turns off the MOS-FET 24 and stops ON / OFF. The power supply voltage (the positive voltage of the capacitor 23) is 0
The control IC 44 turns off the MOS-FET 24 until the power is turned on / reset after the voltage rises above the predetermined level.
To continue. Therefore, the DC chopper operation by the MOS-FET 24 stops, the AC output (secondary) on the secondary side of the transformer 25 disappears, and the DC (secondary) output also disappears, so the output stops. Since the power source of the control IC 44 itself is obtained from the primary DC, the control function is not impaired even when an overcurrent or the like occurs.
【0020】以上のように、過電流に伴って直流出力電
圧Vo1が急激に低下した場合においても、別系統ライ
ン(出力回路50)から増幅回路用電圧を得ているの
で、電源遮断機能を失うことなく、過電流保護が確実に
行なわれる。As described above, even when the DC output voltage Vo1 suddenly drops due to the overcurrent, the amplifier circuit voltage is obtained from the separate system line (output circuit 50), so that the power cutoff function is lost. Without fail, overcurrent protection is reliably performed.
【0021】−第2実施例−
図2には、電源装置に使用される、過電流信号増幅回路
において、電流増幅用トランジスタ40の代わりにサイ
リスタ(あるいはトライアック)48を使用した一例を
示す。図2も図1と大略同様な動作であるが、電流増幅
用トランジスタ40の代わりにサイリスタ(あるいはト
ライアック)48を使用しており、電流検出用トランジ
スタ8がONし、一旦サイリスタ(あるいはトライアッ
ク)48にゲ−ト(G)信号が入力されると、サイリス
タ(あるいはトライアック)48がONをし、通電レベ
ルが実質上零になるまでONを継続する(ラッチされ
る)ため、フォトカプラ41がONし制御用IC44の
MOS−FET24に関するON/OFF制御を停止す
るので、電源装置は出力停止となる。その他の構成およ
び動作は第1実施例と同様であるので説明は省略する。 Second Embodiment FIG. 2 shows an example in which a thyristor (or triac) 48 is used instead of the current amplification transistor 40 in an overcurrent signal amplification circuit used in a power supply device. The operation of FIG. 2 is almost the same as that of FIG. 1 , but a thyristor (or triac) 48 is used instead of the current amplifying transistor 40, and the current detecting transistor 8 is turned on to temporarily turn on the thyristor (or triac) 48. When the gate (G) signal is input to the thyristor (or triac) 48, the photocoupler 41 is turned on because the thyristor (or triac) 48 is kept on (latched) until the energization level becomes substantially zero. Since the ON / OFF control of the MOS-FET 24 of the control IC 44 is stopped, the power supply device stops the output. Other configurations and operations are the same as those in the first embodiment, and the description thereof will be omitted.
【0022】−第3実施例−
図3には、第1の出力回路の上流段で、電流増幅用トラ
ンジスタ40の電源電圧を得る態様を示す。図3の実施
例も、図1の実施例と大略同様な構造および動作である
が、図3において電流増幅用トランジスタ40及びフォ
トカプラ41の発光ダイオ−ドの電源電圧(Vcc)は、
直流(第2次)の全波整流直後、すなわち整流用ダイオ
−ド26,27と平滑用チョ−クコイル30の接続点よ
り分岐して得ている。ダイオ−ド44は整流用であり、
コンデンサ47は電源電圧(Vcc)の平滑用である。 Third Embodiment FIG. 3 shows a mode in which the power supply voltage of the current amplification transistor 40 is obtained in the upstream stage of the first output circuit. The embodiment of FIG. 3 is also a embodiment and generally similar construction and operation of the FIG. 1, the light emitting diode of the current amplifying transistor 40 and the photo-coupler 41 in FIG. 3 - de power supply voltage (Vcc) is,
Immediately after direct-current (secondary) full-wave rectification, that is, obtained by branching from the connection point of the rectifying diodes 26 and 27 and the smoothing choke coil 30. The diode 44 is for rectification,
The capacitor 47 is for smoothing the power supply voltage (Vcc).
【0023】このような回路構成としたので、負荷回路
に短絡等が生じて出力電圧Vo1が大幅に低下したとし
ても、電流検出用抵抗器2及びチョ−クコイル30の上
流側より分岐して電源を得ているので、電流増幅用トラ
ンジスタ40及びフォトカプラ41の電源電圧(Vc
c)を確保することが出来、電流増幅用トランジスタ4
0及びフォトカプラ41で成る遮断回路の過電流保護動
作が確実である。他の構成および動作は第1実施例と同
様であるので説明は省略する。With this circuit configuration, even if the output voltage Vo1 drops significantly due to a short circuit or the like in the load circuit, the power is diverted from the upstream side of the current detection resistor 2 and the choke coil 30. Is obtained, the power supply voltage (Vc
c) can be secured, and the current amplification transistor 4
It is certain that the overcurrent protection operation of the cutoff circuit composed of 0 and the photocoupler 41 is performed. The other structure and operation are the same as those in the first embodiment, and the description thereof will be omitted.
【0024】以上に説明した各実施例の効果を要約する
と次の通りである。
(1) 本発明の電源装置(図1,図2,図3)では、図5
に示す従来の回路と比較し、保護回路に使用される電流
増幅用トランジスタ20及びフォトカプラ21から成る
遮断回路の電源電圧(Vcc)を別系統の電源から得るこ
とにより、出力短絡及び出力短絡起動などの異常時にお
いても、電源電圧(Vcc)低下による遮断回路が作動し
なくなる不具合を解消することが出来、確実な過電流保
護動作を行なうことが出来る。
(2) 本発明の電源装置(図2)において、保護回路に使
用される電流増幅用トランジスタ20の代わりにサイリ
スタ(又はトライアック)28を使用することにより、
過電流発生時により一旦ゲ−ト(G)に信号が加われば
その状態をラッチし、フォトカプラ21を作動させるこ
とにより制御用ICを作動させ、確実に電源停止するこ
とが可能となる。
(3) 本発明の電源装置(図3)において、保護回路に使
用される電流増幅用トランジスタ20及びフォトカプラ
21から成る遮断回路の電源電圧(Vcc)を、直流(2
次)の整流ダイオ−ド出力直後から分岐して別回路によ
り電圧(Vcc)を得ることにより、出力短絡及び出力短
絡起動などの異常時においても、電源電圧を確保するこ
とが出来るので、電源電圧低下による保護回路が作動し
なくなる不具合を解消することが出来、確実な過電流保
護動作を行なうことが出来る。The effects of each embodiment described above are summarized as follows. (1) In the power supply device of the present invention (FIGS. 1, 2, 3), 5
Compared with the conventional circuit shown in FIG. 1, by obtaining the power supply voltage (Vcc) of the interruption circuit composed of the current amplification transistor 20 and the photocoupler 21 used in the protection circuit from the power supply of another system, the output short circuit and the output short circuit start are performed. Even in the event of an abnormality such as the above, it is possible to solve the problem that the cutoff circuit does not operate due to a decrease in the power supply voltage (Vcc), and a reliable overcurrent protection operation can be performed. ( 2 ) In the power supply device of the present invention (FIG. 2 ), by using a thyristor (or triac) 28 instead of the current amplification transistor 20 used in the protection circuit,
Once a signal is applied to the gate (G) due to the occurrence of an overcurrent, the state is latched, and the photocoupler 21 is operated to operate the control IC, so that the power supply can be surely stopped. ( 3 ) In the power supply device of the present invention (FIG. 3 ), the power supply voltage (Vcc) of the interruption circuit composed of the current amplification transistor 20 and the photocoupler 21 used in the protection circuit is set to the direct current (2).
By branching immediately after the output of the rectifying diode in (next) and obtaining the voltage (Vcc) from another circuit, the power supply voltage can be secured even in the event of an output short circuit or an output short circuit start. It is possible to solve the problem that the protection circuit does not operate due to the decrease, and it is possible to perform a reliable overcurrent protection operation.
【図1】 本発明の電源装置の1つである第1実施例を
示す電気回路図である。FIG. 1 is an electric circuit diagram showing a first embodiment which is one of the power supply devices of the present invention.
【図2】 本発明の電源装置の1つである第2実施例を
示す電気回路図である。FIG. 2 is an electric circuit diagram showing a second embodiment which is one of the power supply devices of the present invention.
【図3】 本発明の電源装置の1つである第3実施例を
示す電気回路図である。FIG. 3 is an electric circuit diagram showing a third embodiment which is one of the power supply devices of the present invention.
【図4】 従来の過電流検出回路の1つを示す電気回路
図である。FIG. 4 is an electric circuit diagram showing one of conventional overcurrent detection circuits.
【図5】 従来の電源装置の1つを示す電気回路図であ
る。FIG. 5 is an electric circuit diagram showing one of conventional power supply devices.
1:電源回路 2:電流検出用抵抗器
3:負荷装置 4〜7:分圧用抵抗器
8:電流検出用トランジスタ
9:温度補正用ダイオード
10:分圧用抵抗器 11:電流制限用抵抗器
12:ツェナーダイオード
20:過電流検出回路 21:交流電源
22:整流ブリッジ 23:平滑コンデンサ
24:MOS−FET 25:トランス
26〜29:ダイオ−ド
30,31:チョ−クコイル
32,33:平滑コンデンサ
40:電流増幅用トランジスタ
41:フォトカプラ 42:平滑コンデンサ
43:電圧検出回路 4:制御用IC
45:平滑コンデンサ 46:ダイオ−ド
47:平滑コンデンサ 48:サイリスタ(又はトライ
アック)
50:第2の出力回路 P:パッケ−ジ1: Power supply circuit 2: Resistor for current detection 3: Load device 4-7: Resistor for voltage division 8: Transistor for current detection 9: Diode for temperature correction 10: Resistor for voltage division 11: Resistor for current limitation 12: Zener diode 20: Overcurrent detection circuit 21: AC power supply 22: Rectifying bridge 23: Smoothing capacitor 24: MOS-FET 25: Transformers 26 to 29: Diodes 30, 31: Choke coils 32, 33: Smoothing capacitor 40: Current amplification transistor 41: Photocoupler 42: Smoothing capacitor 43: Voltage detection circuit 4: Control IC 45: Smoothing capacitor 46: Diode 47: Smoothing capacitor 48: Thyristor (or triac) 50: Second output circuit P : Package
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7,DB名) G01R 19/165 G01R 19/32 H02H 3/08 G05F 1/56,320 H02M 7/48 H02M 3/00 ─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) G01R 19/165 G01R 19/32 H02H 3/08 G05F 1 / 56,320 H02M 7/48 H02M 3/00
Claims (4)
トランス,該トランスの1次コイルと前記整流ブリッジ
の間の通電ル−プに介挿されたスイッチング手段、およ
び、過電流検出信号に応答して該スイッチング手段で前
記通電ル−プをオフにする制御手段を含む電源回路;該
電源回路の出力電流が流れる抵抗器を含み該抵抗器の前
記電源回路側の電位と負荷側の電位との電位差に基づき
過電流を検出して過電流信号を発生する過電流検出回
路;および、過電流信号を増幅した過電流検出信号を前
記制御手段に与える増幅手段;を備える電源装置におい
て、 前記増幅手段の電源電圧印加端には、前記過電流検出回
路が監視する電力出力ラインとは別の、所要電圧を与え
るラインに接続したことを特徴とする電源装置。1. A rectifying bridge for converting an alternating current into a direct current,
A transformer, a switching means inserted in an energizing loop between the primary coil of the transformer and the rectifying bridge, and the energizing loop is turned off by the switching means in response to an overcurrent detection signal. A power supply circuit including control means; including a resistor through which an output current of the power supply circuit flows, and detecting an overcurrent based on a potential difference between a potential on the power supply circuit side of the resistor and a potential on the load side to generate an overcurrent signal An overcurrent detecting circuit for amplifying an overcurrent signal, and an amplifying means for giving an overcurrent detecting signal obtained by amplifying the overcurrent signal to the control means. A power supply device characterized in that it is connected to a line that provides a required voltage, which is different from the power output line to be monitored.
トランス,該トランスの1次コイルと前記整流ブリッジ
の間の通電ル−プに介挿されたスイッチング手段,過電
流検出信号に応答して該スイッチング手段で前記通電ル
−プをオフにする制御手段,トランスの2次巻線に接続
した整流器,その整流出力を平滑化するためのチョ−ク
コイル,アノ−ドが該チョ−クコイルの該整流器側に接
続されたダイオ−ド、および、該ダイオ−ドのカソ−ド
と前記チョ−クコイルの他方側に接続されたコンデンサ
を含む電源回路; 該電源回路の出力電流が流れる抵抗器を含み該抵抗器の
前記電源回路側の電位と負荷側の電位との電位差に基づ
き過電流を検出して過電流信号を発生する過電流検出回
路;および、 前記過電流信号を増幅した過電流検出信号を前記制御手
段に与える増幅手段であって、その電源電圧印加端が前
記ダイオ−ドのカソ−ドに接続された増幅手段;を備え
る電源装置。2. A rectifying bridge for converting an alternating current into a direct current,
Transformer, switching means inserted in the energization loop between the primary coil of the transformer and the rectifying bridge, control means for turning off the energization loop by the switching means in response to an overcurrent detection signal A rectifier connected to the secondary winding of the transformer, a choke coil for smoothing the rectified output of the rectifier, a diode having an anode connected to the rectifier side of the choke coil, and the diode. Power supply circuit including a cathode and a capacitor connected to the other side of the choke coil; a potential of the power supply circuit side and a load side potential of the resistor including a resistor through which an output current of the power supply circuit flows. An overcurrent detection circuit for detecting an overcurrent based on a potential difference between the overcurrent detection circuit and an overcurrent detection circuit; and an amplifying means for giving an overcurrent detection signal obtained by amplifying the overcurrent signal to the control means. Voltage application end the diode - de of cathode - amplification means connected to the de; power device comprising a.
イリスタあるいはトライアックを含む、請求項1又は請
求項2に記載の電源装置。3. The power supply device according to claim 1 , wherein the amplification means includes a current amplification transistor, a thyristor or a triac.
位がベ−スに他端の電位がエミッタに加えられる電流検
出用トランジスタと、該電流検出用トランジスタのベー
ス・エミッタ間順方向電圧の温度変化を順方向電圧の温
度変化で相殺するダイオ−ドを含むバイアス手段と、前
記電流検出用トランジスタの過電流検知閾値を設定する
手段を備える、請求項1,請求項2又は請求項3に記載
の電源装置。4. An overcurrent detection circuit comprising a current detection transistor in which a potential at one end of the resistor is applied to a base and a potential at the other end is applied to an emitter, and a forward direction between a base and an emitter of the current detection transistor. diode to cancel the temperature change of the voltage at the temperature change of the forward voltage - comprises a biasing means including de, means for setting the overcurrent detection threshold of the current detection transistor, according to claim 1, claim 2 or claim The power supply device according to item 3 .
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30565095A JP3400216B2 (en) | 1995-08-22 | 1995-11-24 | Power supply |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP21323895 | 1995-08-22 | ||
JP7-213238 | 1995-08-22 | ||
JP30565095A JP3400216B2 (en) | 1995-08-22 | 1995-11-24 | Power supply |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH09119949A JPH09119949A (en) | 1997-05-06 |
JP3400216B2 true JP3400216B2 (en) | 2003-04-28 |
Family
ID=26519679
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP30565095A Expired - Lifetime JP3400216B2 (en) | 1995-08-22 | 1995-11-24 | Power supply |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3400216B2 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3501119B2 (en) * | 2000-12-06 | 2004-03-02 | 株式会社村田製作所 | Switching power supply |
JP5202119B2 (en) * | 2008-06-11 | 2013-06-05 | 株式会社ケーヒン | Multi-output judgment circuit |
KR101034754B1 (en) * | 2008-12-31 | 2011-05-17 | 엘에스산전 주식회사 | Watt-hour meter and control method using the same |
JP5539262B2 (en) * | 2011-05-24 | 2014-07-02 | 日立オートモティブシステムズ株式会社 | Electromagnetic load control device |
JP7000966B2 (en) * | 2018-04-04 | 2022-01-19 | 株式会社デンソー | Switch overcurrent detection circuit |
JP6919628B2 (en) | 2018-06-25 | 2021-08-18 | 株式会社オートネットワーク技術研究所 | Current detection circuit and power supply |
CN118209776B (en) * | 2024-05-21 | 2024-07-23 | 西安奇点能源股份有限公司 | Overcurrent detection circuit of H-bridge circuit and overcurrent detection method of H-bridge circuit |
-
1995
- 1995-11-24 JP JP30565095A patent/JP3400216B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
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JPH09119949A (en) | 1997-05-06 |
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