JPH0624439B2 - Switching Regulator - Google Patents
Switching RegulatorInfo
- Publication number
- JPH0624439B2 JPH0624439B2 JP59208736A JP20873684A JPH0624439B2 JP H0624439 B2 JPH0624439 B2 JP H0624439B2 JP 59208736 A JP59208736 A JP 59208736A JP 20873684 A JP20873684 A JP 20873684A JP H0624439 B2 JPH0624439 B2 JP H0624439B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- output
- voltage
- series
- transistor
- 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
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
- H02M3/338—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 in a self-oscillating arrangement
Description
【発明の詳細な説明】 〔発明の利用分野〕 本発明はスイツチングレギユレータに係り、特にその出
力短絡保護手段に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching regulator, and more particularly to an output short circuit protection means for the switching regulator.
第３図は、従来のトランジスタ飽和型弛張発振回路の一
例を示す回路図である。同図において、負極が接地され
ている直流電源１があり、その正極はトランス９の一次
巻線に接続され、この一次巻線の他端は発振トランジス
タ３および抵抗５を介して接地されている。また、前記
発振トランジスタ３のベースは起動抵抗２を介して前記
直流電源１の正極に接続されている。一方、前記トラン
ス９には一端が接地された別個の一次巻線がありこの他
端は抵抗７とコンデンサ８の並列体を介して前記発振ト
ランジスタ３のベースに接続されている。FIG. 3 is a circuit diagram showing an example of a conventional transistor saturation type relaxation oscillation circuit. In the figure, there is a DC power supply 1 whose negative electrode is grounded, its positive electrode is connected to the primary winding of a transformer 9, and the other end of this primary winding is grounded via an oscillation transistor 3 and a resistor 5. . The base of the oscillation transistor 3 is connected to the positive electrode of the DC power supply 1 via the starting resistor 2. On the other hand, the transformer 9 has a separate primary winding, one end of which is grounded, and the other end of which is connected to the base of the oscillation transistor 3 via a parallel body of a resistor 7 and a capacitor 8.
また、トランス９の１つの二次巻線の両端には整流ダイ
オード１０とコンデンサ１２の直列体が接続され、該コ
ンデンサ１２間には直列型定電圧回路１５が接続されて
いる。そして、この直列型定電圧回路１５の出力側には
コンデンサ１４が並列接続されている。さらにトランス
９の他の二次巻線には整流ダイオード１１とコンデンサ
１３の直列体が接続され、この整流ダイオード１１とコ
ンデンサ１３の接続点は電圧誤差検出回路の入力端子の
一に接続されており、この電圧誤差検出回路の出力端子
は制御トランジスタ４のベース、および抵抗６を介して
前記発振トランジスタ３と抵抗５の接続点に接続されて
いる。なお、前記制御トランジスタ４は前記発振トラン
ジスタ３のベースと接地間に介在されたものである。A series body of a rectifying diode 10 and a capacitor 12 is connected to both ends of one secondary winding of the transformer 9, and a series type constant voltage circuit 15 is connected between the capacitors 12. The capacitor 14 is connected in parallel to the output side of the serial constant voltage circuit 15. Further, a series body of a rectifying diode 11 and a capacitor 13 is connected to the other secondary winding of the transformer 9, and the connection point of the rectifying diode 11 and the capacitor 13 is connected to one of the input terminals of the voltage error detection circuit. The output terminal of this voltage error detection circuit is connected to the base of the control transistor 4 and the connection point between the oscillation transistor 3 and the resistance 5 via the resistance 6. The control transistor 4 is interposed between the base of the oscillation transistor 3 and the ground.
このように構成されたスイツチングレギユレータは、出
力短絡時に一次側の発振トランジスタ３に過電流が流れ
るのを過電流検出用の抵抗５によつて検出し、この抵抗
５間の電圧が必要以上に上昇した場合、制御トランジス
タ４のベースにベース電流を供給するようになつてい
る。そして、該発振トランジスタ３のベース電流を抑制
して二次側の出力を抑制するようになつている。The switching regulator configured as described above detects that an overcurrent flows through the oscillation transistor 3 on the primary side when the output is short-circuited by the resistor 5 for detecting the overcurrent, and the voltage across the resistor 5 is required. When the voltage rises above the level, the base current is supplied to the base of the control transistor 4. Then, the base current of the oscillation transistor 3 is suppressed to suppress the output on the secondary side.
しかしながら、過電流の設定は、二次側出力の定格最大
電力が供給できるように設定される必要があるもので、
このため、二次側出力短絡時には、定格最大電力以上の
電力が負荷に供給されることになる。したがつて、直列
型定電圧回路１５出力が短絡した場合、直列定電圧回路
１５に過電流が流れ、この直列型定電圧回路１５が熱破
壊するという欠点が生じる。However, the setting of the overcurrent needs to be set so that the rated maximum power of the secondary output can be supplied,
For this reason, when the secondary side output is short-circuited, the electric power of the rated maximum electric power or more is supplied to the load. Therefore, when the output of the series-type constant voltage circuit 15 is short-circuited, an overcurrent flows in the series-type constant-voltage circuit 15 and the series-type constant-voltage circuit 15 is thermally destroyed.
本発明の目的は、このような事情に基づいてなされたも
のであり、直列型定電圧回路の出力短絡時に、該直列型
定電圧回路の破損を防止するようにしたスイツチングレ
ギユレータを提供するにある。The object of the present invention has been made under such circumstances, and provides a switching regulator which prevents damage to the series type constant voltage circuit when the output of the series type constant voltage circuit is short-circuited. There is.
このような目的を達成するために、本発明は、トランジ
スタ飽和型弛張発振回路と、このトランジスタ飽和型弛
張発振回路によつて駆動されるトランスと、このトラン
スの出力を整流する第１整流回路と、この第１整流回路
の出力側に接続される直列型定電圧回路と、前記トラン
スの出力を整流する第２整流回路と、この第２整流回路
の出力に応じて前記トランジスタ飽和型弛張発振回路の
トランジスタのベース電流を制御する電圧誤差検出回路
とを具備するスイツチングレギユレータにおいて、通常
動作時における前記直列型定電圧回路の入出力電圧差よ
りも大きい電圧差を基準電圧とし、前記入出力電圧差が
前記基準電圧より大きい場合は、前記トランジスタ飽和
型弛張発振回路の発振を停止する手段を設けるようにし
たものである。In order to achieve such an object, the present invention provides a transistor saturation type relaxation oscillation circuit, a transformer driven by the transistor saturation type relaxation oscillation circuit, and a first rectification circuit for rectifying the output of the transformer. A series constant voltage circuit connected to the output side of the first rectifier circuit, a second rectifier circuit that rectifies the output of the transformer, and the transistor saturation type relaxation oscillation circuit according to the output of the second rectifier circuit. In the switching regulator including a voltage error detection circuit for controlling the base current of the transistor, the voltage difference larger than the input / output voltage difference of the series type constant voltage circuit during normal operation is used as the reference voltage, When the output voltage difference is larger than the reference voltage, means for stopping the oscillation of the transistor saturation type relaxation oscillation circuit is provided.
第１図は本発明によるスイツチングレギユレータの一実
施例を示す回路図である。同図において、第３図と同符
号のものは同一部品を示している。第３図と異なる構成
は、直列型定電圧回路１５の入出力間に出力端から順次
抵抗１７、ツエナーダイオード２１フオトカプラ２０の
発光素子が直列に接続されている。そして負極が接地さ
れた直流電源１８の正極が前記フオトカプラ２０の受光
素子および抵抗１９を順次介して電圧誤差検出回路の出
力端に接続されている。FIG. 1 is a circuit diagram showing an embodiment of a switching regulator according to the present invention. In the figure, the same reference numerals as those in FIG. 3 indicate the same parts. The configuration different from that of FIG. 3 is such that a resistor 17, a Zener diode 21 and a light emitting element of a photocoupler 20 are sequentially connected in series from the output terminal between the input and output of the series type constant voltage circuit 15. The positive electrode of the DC power supply 18 whose negative electrode is grounded is connected to the output end of the voltage error detection circuit through the light receiving element of the photocoupler 20 and the resistor 19 sequentially.
ここで、第１図に示すスイツチングレギユレータは、通
常動作時は、Ｎ２巻線出力で、定電圧制御されており、
Ｎ３巻線出力つまり、直列型定電圧回路１５の入力電圧
Ｖ１もほぼ一定に制御され、直列型定電圧回路１５の入
出力電圧差は、ある一定の範囲の電圧に保たれる。ツエ
ナダイオード２１のツエナー電圧Ｖｚを、直列型電圧回
路１５の通常時の入出力電圧差より大きく選ぶことによ
り、通常動作時は、フオトカプラ２０は、動作せず、制
御用トランジスタ４は、電圧誤差検出回路１６により制
御されている。次に、Ｎ３巻線の出力Ｖ０の短絡時は、
直列型電圧回路１５の入出力電圧差Ｖ１−Ｖ０は、ツエ
ナーダイオード２１のツエナー電圧Ｖｚより高くなりフ
オトカプラ２０の発光ダイオードに電流が流れ、直流電
源１８より、抵抗１９を通して、制御用トランジスタ４
にベース電流を供給し、発振トランジスタ３の発振を抑
制し、二次側の出力を抑える。Here, the switching regulator shown in FIG. 1 is under constant voltage control with N 2 winding output during normal operation.
The output of the N 3 winding, that is, the input voltage V 1 of the series constant voltage circuit 15 is also controlled to be substantially constant, and the input / output voltage difference of the series constant voltage circuit 15 is maintained within a certain range of voltage. By selecting the Zener voltage V z of the Zener diode 21 to be larger than the normal input / output voltage difference of the series voltage circuit 15, the photocoupler 20 does not operate during normal operation, and the control transistor 4 has a voltage error. It is controlled by the detection circuit 16. Next, when the output V 0 of the N 3 winding is short-circuited,
The input / output voltage difference V 1 -V 0 of the series voltage circuit 15 becomes higher than the zener voltage V z of the zener diode 21, and a current flows through the light emitting diode of the photocoupler 20, and the DC power source 18 passes through the resistor 19 to control transistor. Four
A base current is supplied to suppress the oscillation of the oscillation transistor 3 and suppress the output on the secondary side.
したがって、本実施例は、前述したような短絡保護回路
を設けることによつて、直列型定電圧回路１５の出力短
絡時にも、直列型定電圧回路１５の入出力電圧差が、Ｖ
ｚ以上になるのを防ぎ、なおかつ、スイツチングレギユ
レータの出力電力を絞り込むことによつて、直列型定電
圧回路１５の熱破壊を防ぐとともに、出力に過電流の流
れるのを防ぐことができる。Therefore, in the present embodiment, by providing the short-circuit protection circuit as described above, even when the output of the series-type constant voltage circuit 15 is short-circuited, the input-output voltage difference of the series-type constant-voltage circuit 15 becomes V.
It is possible to prevent the series constant voltage circuit 15 from being destroyed by heat and to prevent an overcurrent from flowing to the output by preventing the voltage from becoming equal to or higher than z and reducing the output power of the switching regulator. .
また、本実施例においては、電圧誤差検出回路１６が異
常となり、制御トランジスタ４に正常な帰還がかからな
くなり、二次側電圧が大きくなつた場合も、直列型定電
圧回路１５の入出力電圧差が、ツエナーダイオード２１
のツエナー電圧より大きくなり、発振トランジスタ３の
発振を抑制し、直列型定電圧回路１５に過電圧のかかる
のを防ぐことができる。Further, in the present embodiment, even when the voltage error detection circuit 16 becomes abnormal, normal feedback is not applied to the control transistor 4, and the secondary side voltage increases, the input / output voltage of the series type constant voltage circuit 15 is also increased. The difference is the Zener diode 21
It is possible to suppress the oscillation of the oscillation transistor 3 and prevent an overvoltage from being applied to the series-type constant voltage circuit 15 because the voltage becomes higher than the Zener voltage of 1.
本発明の他の実施例を第２図に示す。回路構成は、第１
図とほぼ同様で、フオトカプラ２０の出力側に、抵抗１
９を通して、サイリスタ２２のゲートに接続されてい
る。Another embodiment of the present invention is shown in FIG. The circuit configuration is the first
In the same way as the figure, the resistor 1 is connected to the output side of the photo coupler 20.
It is connected to the gate of the thyristor 22 through 9.
前記サイリスタ２２は、ゲートにＯＮ信号が与えられる
と、発振トランジスタ３のベース、エミツタを短絡し、
発振を停止する。つまり、直列型定電圧回路１５の入出
力電圧差がツエナーダイオード２１のツエナー電圧より
大きくなつた場合は、フオトカプラ２０の発光ダイオイ
ードに電流が流れ、サイリスタ２２をＯＮさせ、スイツ
チングトランジスタの発振を停止させることにより、短
絡保護を行うことができる。The thyristor 22 short-circuits the base and the emitter of the oscillation transistor 3 when an ON signal is applied to its gate,
Stop oscillation. That is, when the input / output voltage difference of the series type constant voltage circuit 15 becomes larger than the Zener voltage of the Zener diode 21, a current flows in the light emitting diode of the photocoupler 20, the thyristor 22 is turned on, and the oscillation of the switching transistor is stopped. By doing so, short-circuit protection can be performed.
以上、詳述したように、本発明によれば、通常動作時に
おける直列型定電圧回路の入出力電圧差よりも大きい電
圧差を基準電圧とし、前記入出力電圧差が前記基準電圧
より大きい場合は、トランジスタ飽和型弛張発振回路の
発振を停止する手段によつて、前記直列定電圧回路の出
力が短絡した場合に、前記直列定電圧回路の破損を防止
することができ、スイツチングレギユレータの短絡保護
を比較的簡単な回路で行なうことができる。As described above in detail, according to the present invention, when the voltage difference larger than the input / output voltage difference of the series type constant voltage circuit in the normal operation is used as the reference voltage, the input / output voltage difference is larger than the reference voltage. The means for stopping the oscillation of the transistor saturation type relaxation oscillation circuit can prevent the series constant voltage circuit from being damaged when the output of the series constant voltage circuit is short-circuited. The short circuit protection can be performed with a relatively simple circuit.
第１図は本発明によるスイツチングレギユレータの一実
施例を示す回路図、第２図は本発明によるスイツチング
レギユレータの他の実施例を示す回路図、第３図は従来
のスイツチングレギユレータの一例を示す回路図であ
る。 １，１８……直流電源、２……起動抵抗、３……発振ト
ランジスタ、４……制御トランジスタ、５，６，７，１
７，１９……抵抗、８，１２，１３，１４……コンデン
サ、９……トランス、１０，１１……直流ダイオード、
１５……直列型定電圧回路、１６……電圧誤差検出回
路、２０……フオトカプラ、２１……ツエナーダイオー
ド。1 is a circuit diagram showing one embodiment of a switching regulator according to the present invention, FIG. 2 is a circuit diagram showing another embodiment of a switching regulator according to the present invention, and FIG. 3 is a conventional switch. FIG. 3 is a circuit diagram showing an example of an engregulator. 1, 18 ... DC power supply, 2 ... Start-up resistance, 3 ... Oscillation transistor, 4 ... Control transistor, 5, 6, 7, 1
7, 19 ... Resistance, 8, 12, 13, 14 ... Capacitor, 9 ... Transformer, 10, 11 ... DC diode,
15 ... Series constant voltage circuit, 16 ... Voltage error detection circuit, 20 ... Photocoupler, 21 ... Zener diode.
Claims (1)
トランジスタ飽和型弛張発振回路によつて駆動されるト
ランスと、このトランスの出力を整流する第１整流回路
と、この第１整流回路の出力側に接続される直列型定電
圧回路と、前記トランスの出力を整流する第２整流回路
と、この第２整流回路の出力に応じて前記トランジスタ
飽和型弛張発振回路のトランジスタのベース電流を制御
する電圧誤差検出回路とを具備するスイツチングレギユ
レータにおいて、通常動作時における前記直列型定電圧
回路の入出力電圧差よりも大きい電圧差を基準電圧と
し、前記入出力電圧差が前記基準電圧より大きい場合
は、前記トランジスタ飽和型弛張発振回路の発振を停止
する手段を設けるようにしたことを特徴とするスイツチ
ングレギユレータ。1. A transistor saturation type relaxation oscillation circuit, a transformer driven by the transistor saturation type relaxation oscillation circuit, a first rectification circuit for rectifying the output of the transformer, and an output side of the first rectification circuit. A constant voltage circuit connected in series, a second rectifying circuit for rectifying the output of the transformer, and a voltage for controlling the base current of the transistor of the transistor saturation type relaxation oscillation circuit according to the output of the second rectifying circuit. In a switching regulator including an error detection circuit, a voltage difference larger than an input / output voltage difference of the series type constant voltage circuit during normal operation is used as a reference voltage, and the input / output voltage difference is larger than the reference voltage. In this case, a switching regulator is provided with means for stopping the oscillation of the transistor saturation relaxation oscillator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59208736A JPH0624439B2 (en) | 1984-10-04 | 1984-10-04 | Switching Regulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59208736A JPH0624439B2 (en) | 1984-10-04 | 1984-10-04 | Switching Regulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6188766A JPS6188766A (en) | 1986-05-07 |
| JPH0624439B2 true JPH0624439B2 (en) | 1994-03-30 |
Family
ID=16561226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59208736A Expired - Lifetime JPH0624439B2 (en) | 1984-10-04 | 1984-10-04 | Switching Regulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0624439B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE58907619D1 (en) * | 1989-09-29 | 1994-06-09 | Siemens Ag | Circuit arrangement for a flyback switching power supply. |
| JP2993210B2 (en) * | 1991-09-10 | 1999-12-20 | 松下電器産業株式会社 | Power circuit protection device |
| JP5549159B2 (en) * | 2009-09-09 | 2014-07-16 | 富士電機株式会社 | Power supply |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0226166Y2 (en) * | 1984-09-12 | 1990-07-17 |
-
1984
- 1984-10-04 JP JP59208736A patent/JPH0624439B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6188766A (en) | 1986-05-07 |
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