JPS5932990B2 - switching regulator - Google Patents
switching regulatorInfo
- Publication number
- JPS5932990B2 JPS5932990B2 JP2386280A JP2386280A JPS5932990B2 JP S5932990 B2 JPS5932990 B2 JP S5932990B2 JP 2386280 A JP2386280 A JP 2386280A JP 2386280 A JP2386280 A JP 2386280A JP S5932990 B2 JPS5932990 B2 JP S5932990B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- output
- error amplifier
- switching regulator
- transformer
- 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
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
- H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Protection Of Static Devices (AREA)
Description
【発明の詳細な説明】
本発明は、トランスを有するスイッチング・レギュレー
タの改良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in switching regulators having transformers.
この種のスイッチング・レギュレータは第１図に示すよ
うに、入力電圧Ｅ１がトランス１の一次巻線ｎｌとスイ
ッチング素子であるトランジスタ２の直列回路に加えら
れる。In this type of switching regulator, as shown in FIG. 1, an input voltage E1 is applied to a series circuit of a primary winding nl of a transformer 1 and a transistor 2, which is a switching element.
そしてトランジスタ２がオンになると一次電流ｉｌが流
れ、オフになるとｉｌによつてトランス１の鉄心に貯え
られたエネルギが二次巻線ｎ２、ｎ３側に二次電流ｉ２
、ｉ３として放出される。二次巻線ｎ２側の二次電流ｉ
２は整流平滑回路３で整流平滑され、出力電圧Ｅｏとな
つて出力端子ＯＵＴに生ずる。また二次巻線ｎ３側の二
次電流ｉ３は整流平滑回路４で整流平滑された後抵抗Ｒ
１ 、Ｒ２で分圧され、出力電圧Ｅｏに関連した帰還電
圧Ｅｆとなつて誤差増幅器５に与えられる。誤差増幅器
５は帰還電圧Ｅｆと基準電圧Ｅｓとの偏差を増幅し、そ
の出力が比較器６で発振器７からの三角波の比較電圧Ｅ
ｒと比較される。その比較結果に基づいて駆動回路８が
トランジスタ２のオンオフを制御する。このようにして
トランジスタ２がＥｆ＝Ｅｓになるようにオンオフを繰
り返し、出力電圧Ｅｏを一定値に制御する。このような
構成のスイッチング・レギュレータにおいては、帰還回
路を構成するトランス１の二次巻線ｎ３に断線事故が発
生したり、整流平滑回路４および抵抗Ｒ１ 、Ｒ２に故
障が生ずると、トランジスタ２がほとんどオンになるた
め、出力側に過電圧が発生する。その値は正常値の２倍
以上にもなり、特に入力電圧範囲が例えば２４Ｖ〜１０
０Ｖのように広い場合にはその値が大きくなるので、対
策が必要となる。ところで、トランスを有するスイッチ
ング・レギュレータでは、トランジスタ２がオンからオ
フに切換わり 次電流が流れたとき、一次側にフライバ
ック電圧が誘起される。When the transistor 2 is turned on, the primary current il flows, and when the transistor 2 is turned off, the energy stored in the iron core of the transformer 1 is transferred to the secondary windings n2 and n3 through the secondary current i2.
, i3. Secondary current i on secondary winding n2 side
2 is rectified and smoothed by the rectification and smoothing circuit 3, and is generated as an output voltage Eo at the output terminal OUT. Further, the secondary current i3 on the side of the secondary winding n3 is rectified and smoothed by the rectifying and smoothing circuit 4, and then resistor R
1 and R2, and is applied to the error amplifier 5 as a feedback voltage Ef related to the output voltage Eo. The error amplifier 5 amplifies the deviation between the feedback voltage Ef and the reference voltage Es, and its output is sent to the comparator 6 as a triangular wave comparison voltage E from the oscillator 7.
compared with r. The drive circuit 8 controls on/off of the transistor 2 based on the comparison result. In this way, the transistor 2 is repeatedly turned on and off so that Ef=Es, and the output voltage Eo is controlled to a constant value. In a switching regulator having such a configuration, if a disconnection occurs in the secondary winding n3 of the transformer 1 that constitutes the feedback circuit, or if a failure occurs in the rectifier and smoothing circuit 4 and the resistors R1 and R2, the transistor 2 Since it is almost turned on, an overvoltage occurs on the output side. The value is more than twice the normal value, especially when the input voltage range is from 24V to 10V.
If the voltage is wide such as 0V, the value becomes large, so countermeasures are required. By the way, in a switching regulator having a transformer, when the transistor 2 is switched from on to off and the next current flows, a flyback voltage is induced on the primary side.
このときトランスの漏れインダクタンスによりスパイク
電圧が発生するので、図に示すようにトランス１の一次
巻線ｎｌに並列にダイオードＤ１と抵抗Ｒ３およびコン
デンサＣからなるスナバ回路９が一般に付加されている
。このスナバ回路９にはフライバック電圧の平均値Ｅｆ
ｌが貯えられている。そしてフライバック電圧の平均値
Ｅｆｌと出力電圧Ｅｏとの間にはトｎ１ランス１の巻線
比をＫ（＝）とするとＥｆｌ．＋ＫＥＯなる関係がある
。At this time, a spike voltage is generated due to the leakage inductance of the transformer, so a snubber circuit 9 consisting of a diode D1, a resistor R3, and a capacitor C is generally added in parallel to the primary winding nl of the transformer 1, as shown in the figure. This snubber circuit 9 has an average value Ef of the flyback voltage.
l is stored. Between the average value Efl of the flyback voltage and the output voltage Eo, if the winding ratio of the transformer n1 and the lance 1 is K (=), Efl. There is a +KEO relationship.
そこで本発明では、フライバツク電圧を監視し帰還回路
が異常になつたときその値を制限するようにして、過電
圧の発生を有効に防止できるスイツチング・レギユレー
タを実現したものである。Therefore, the present invention realizes a switching regulator that can effectively prevent the occurrence of overvoltage by monitoring the flyback voltage and limiting its value when the feedback circuit becomes abnormal.
第２図は本発明の一実施例を示す接続図である。第２図
において第１図の従来例と異るところは、第２の誤差増
幅器１０を設け、その一方の入力端子にフライバツク電
圧の平均値Ｅｆｌと入力電圧Ｅｌの和を抵抗Ｒ４，Ｒ５
で分圧して与え、他方の入力端子に入力電圧Ｅｌおよび
制限電圧Ｅｌをそれぞれ抵抗Ｒ６，Ｒ７およびＲ８を介
して与えることによつて、その出力端にＥｌとＥｆｌの
偏差に関連した出力電圧Ｅｂを生じさせるとともに、こ
の出力電圧Ｅｂと第１の誤差増１陽器５の出力Ｅａの大
きい方を選択して比較器６に与えるための選択回路１１
を設けた点である。なお選択回路１１として図にはダイ
オードＤ２，Ｄ３からなるものが例示してある。そして
また正常時にはＥａ＞Ｅｂになるように、制限電圧Ｅ，
の値を正常時のＥｆ！の１．４倍程度に選んである。し
たがつて本発明においては、正常時には第１の誤差増幅
器出力Ｅａが第２の誤差増幅器出力Ｅｂより大きく、第
１の誤差増幅器５側で従来同様出力電圧ＥＯを制御して
いる。FIG. 2 is a connection diagram showing one embodiment of the present invention. The difference in FIG. 2 from the conventional example shown in FIG. 1 is that a second error amplifier 10 is provided, and the sum of the average value Efl of the flyback voltage and the input voltage El is connected to one input terminal of the resistor R4, R5.
By applying the input voltage El and the limiting voltage El to the other input terminal via resistors R6, R7 and R8, respectively, an output voltage Eb related to the deviation between El and Efl is applied to the output terminal. A selection circuit 11 selects the larger of this output voltage Eb and the output Ea of the first error amplifier 5 and supplies it to the comparator 6.
The point is that It should be noted that the selection circuit 11 is illustrated in the figure as an example consisting of diodes D2 and D3. Also, in order to make Ea>Eb during normal operation, the limiting voltage E,
The value of Ef! It is selected to be about 1.4 times that of the previous year. Therefore, in the present invention, the first error amplifier output Ea is larger than the second error amplifier output Eb during normal operation, and the output voltage EO is controlled on the first error amplifier 5 side as in the conventional case.
ところで第１の誤差増幅器５側の帰還回路に異常が生じ
て出力電圧ＥＯが高くなつた場合には、フライバツク電
圧が大きくなるので、Ｅｂ＞Ｅａとなり第２の誤差増幅
器１０側が働き、Ｅｆｌ＝Ｅｌとなるようにトランジス
タ２のオンオフが制御され、フライバツク電圧を制限す
る。その結果出力電圧ＥＯも正常時の１．４倍程度に制
限され、出力側に過電王が発生するのを有効に防止でき
る。なお、上述では、選択回路１１としてダイオードＤ
ｌ，Ｄ２からなるものを例示したが、両誤差増幅器出力
Ｅａ，Ｅｂのうちスイツチング素子２のオン時間を短か
くする方向の出力を選択するものであれば、例えば第１
，第２の誤差増幅器５，１０の出力段のトランジスタの
エミツタを共通に接続する等必要に応じて種々の構成の
ものを用いることができる。By the way, if an abnormality occurs in the feedback circuit on the first error amplifier 5 side and the output voltage EO becomes high, the flyback voltage becomes large, so Eb>Ea, and the second error amplifier 10 side works, and Efl=El. The on/off of transistor 2 is controlled so that the flyback voltage is limited. As a result, the output voltage EO is also limited to about 1.4 times the normal voltage, and it is possible to effectively prevent overvoltage from occurring on the output side. In addition, in the above description, the diode D is used as the selection circuit 11.
1 and D2, but if the output in the direction of shortening the ON time of the switching element 2 is selected from among both error amplifier outputs Ea and Eb, for example, the first
, the emitters of the output stage transistors of the second error amplifiers 5 and 10 are connected in common, and various configurations can be used as required.
以上説明したように本発明においては、フライバツク電
圧を監視し、異常時にその値を制限するようにしている
ので、簡単な構成で出力側に過電圧が発生するのを有効
に防止できるスイツチング・レギユレータが得られる。As explained above, in the present invention, the flyback voltage is monitored and its value is limited in the event of an abnormality, so a switching regulator that can effectively prevent overvoltage from occurring on the output side with a simple configuration is provided. can get.
第１図は従来のスイツチング・レギユレータの一例を示
す接続図、第２図は本発明スイツチング・レギユレータ
一の一実施例を示す接続図である。
１・・・・・・トランス、２・・・・・・スイツチング
素子、３，４・・・・・・整流平滑回路、５，１０・・
・・・・誤差増幅器、６・・・・・・比較器、７・・・
・・・発振器、９・・・・・・スナバ回路、１１・・・
・・・選択回路。FIG. 1 is a connection diagram showing an example of a conventional switching regulator, and FIG. 2 is a connection diagram showing an embodiment of the switching regulator of the present invention. 1... Transformer, 2... Switching element, 3, 4... Rectifying and smoothing circuit, 5, 10...
...Error amplifier, 6...Comparator, 7...
...Oscillator, 9...Snubber circuit, 11...
...Selection circuit.
Claims (1)
いて、出力電圧に関連する帰還電圧と基準電圧との偏差
を増幅する第１の誤差増幅器と、トランスの一次巻線に
発生するフライバック電圧に関連する電圧と制限電圧と
の偏差を増幅する第２の誤差増幅器と、第１の誤差増幅
器の出力と第２の誤差増幅器の出力のいずれか一方を選
択する手段と、選択された出力と比較電圧とを比較し、
その比較結果に基づいてスイッチング素子のオンオフを
制御する手段とを具え、前記両誤差増幅器出力のうちス
イッチング素子のオン時間を短かくする方向の出力を選
択手段が選択するようにして、出力側を過電圧から保護
することを特徴とするスイッチング・レギュレータ。1. In a switching regulator having a transformer, a first error amplifier amplifies the deviation between the feedback voltage related to the output voltage and the reference voltage, and the voltage related to the flyback voltage generated in the primary winding of the transformer and the limiting voltage. a second error amplifier for amplifying the deviation between the first error amplifier and the second error amplifier; means for selecting either the output of the first error amplifier or the output of the second error amplifier; and comparing the selected output with a comparison voltage;
means for controlling the on/off of the switching element based on the comparison result, and the selection means selects the output in the direction of shortening the on time of the switching element among the outputs of both error amplifiers, so that the output side is controlled. A switching regulator that features overvoltage protection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2386280A JPS5932990B2 (en) | 1980-02-27 | 1980-02-27 | switching regulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2386280A JPS5932990B2 (en) | 1980-02-27 | 1980-02-27 | switching regulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56121366A JPS56121366A (en) | 1981-09-24 |
| JPS5932990B2 true JPS5932990B2 (en) | 1984-08-13 |
Family
ID=12122244
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2386280A Expired JPS5932990B2 (en) | 1980-02-27 | 1980-02-27 | switching regulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5932990B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5866578A (en) * | 1981-10-15 | 1983-04-20 | Shindengen Electric Mfg Co Ltd | One-element type forward converter |
| JPS5872949U (en) * | 1981-11-06 | 1983-05-17 | 三菱電機株式会社 | capacitor charging power supply |
| JPS634186U (en) * | 1986-06-25 | 1988-01-12 | ||
| JPH0636650B2 (en) * | 1987-07-06 | 1994-05-11 | エルコ−株式会社 | Overvoltage protection circuit for switching regulator |
| US4924369A (en) * | 1988-01-26 | 1990-05-08 | Siemens Aktiengesellschaft | Regulated blocking converter wherein switch conduction time increases with higher output voltages |
| JP7044093B2 (en) * | 2019-05-08 | 2022-03-30 | 横河電機株式会社 | Overvoltage protection circuit and power supply |
-
1980
- 1980-02-27 JP JP2386280A patent/JPS5932990B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56121366A (en) | 1981-09-24 |
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