JP2861312B2 - Forward DC-DC converter - Google Patents
Forward DC-DC converterInfo
- Publication number
- JP2861312B2 JP2861312B2 JP19023390A JP19023390A JP2861312B2 JP 2861312 B2 JP2861312 B2 JP 2861312B2 JP 19023390 A JP19023390 A JP 19023390A JP 19023390 A JP19023390 A JP 19023390A JP 2861312 B2 JP2861312 B2 JP 2861312B2
- Authority
- JP
- Japan
- Prior art keywords
- winding
- switching element
- transformer
- main switching
- control
- 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
Landscapes
- Dc-Dc Converters (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はフォワード型DC−DCコンバータに関する。Description: TECHNICAL FIELD The present invention relates to a forward DC-DC converter.
従来のフォワード型DC−DCコンバータの一例を第２図
に示す。入力電源５の正極と、トランス１の第１の巻線
1aの巻き始めと、第１の巻線1aと同回数巻いた第２の巻
線1bの巻き終りとが接続され、第１の巻線1aの巻き終り
はメインスイッチング素子７の電流入力端子に接続され
ている。第２の巻線1bの巻き始めはトランス１のリセッ
ト電流導通用のダイオード16のカソード端子に接続さ
れ、ダイオード16のアノード端子は入力電源５の負極と
メインスイッチング素子７の電流出力端子とに接続され
ている。トランス１の第３の巻線1cの巻き始めと巻き終
りとは各々整流平滑回路４の２つの入力端子に接続さ
れ、整流平滑回路４の正負の出力は各々正負の出力端子
20,21と安定化制御回路18とに入力されている。安定化
制御回路18の出力はメインスイッチング素子７のON/OFF
制御端子に接続され、出力電源が安定化されるようにメ
インスイッチング素子のON時間を制御するようになって
いる。FIG. 2 shows an example of a conventional forward type DC-DC converter. Positive electrode of input power supply 5 and first winding of transformer 1
The winding start of 1a and the end of the second winding 1b wound the same number of times as the first winding 1a are connected, and the end of the winding of the first winding 1a is connected to the current input terminal of the main switching element 7. It is connected. The beginning of winding of the second winding 1b is connected to the cathode terminal of the reset current conducting diode 16 of the transformer 1, and the anode terminal of the diode 16 is connected to the negative electrode of the input power supply 5 and the current output terminal of the main switching element 7. Have been. The beginning and end of the third winding 1c of the transformer 1 are connected to two input terminals of the rectifying / smoothing circuit 4, respectively, and the positive and negative outputs of the rectifying / smoothing circuit 4 are respectively positive and negative output terminals.
20, 21 and the stabilization control circuit 18. The output of the stabilization control circuit 18 is the ON / OFF of the main switching element 7.
It is connected to a control terminal and controls the ON time of the main switching element so that the output power is stabilized.
上述した従来のフォワード型DC−DCコンバータでは、
第１の巻線と第２の巻線の巻数を増した際に、巻線の浮
遊容量が増大し、メインスイッチング素子のOFF時に第
２の巻線に発生する逆起電力が、メインスイッチング素
子のON時に発生する逆電力よりも小さくなってしまうた
めに、リセット電流導通用のダイオードが導通せずにリ
セット電流が流れなくなり、トランスが磁気飽和を起し
やすくなるという欠点がある。In the conventional forward type DC-DC converter described above,
When the number of turns of the first winding and the second winding is increased, the stray capacitance of the winding increases, and the back electromotive force generated in the second winding when the main switching element is turned off is generated by the main switching element. Is smaller than the reverse power generated when the transistor is turned on, the reset current conduction diode does not conduct, so that the reset current does not flow, and the transformer is liable to cause magnetic saturation.
本発明のフォワード型DC−DCコンバータは、入力電源
と；同一回数巻かれた第１及び第２の巻線と第３の巻線
とを有し第１の巻線の巻始めと第２の巻線の巻終りがと
もに前記入力電源の一方の極に接続されたトランスと；
前記トランスの第１の巻線の巻終りと前記入力電源の他
方の極との間に接続され入力電流のスイッチングを行う
メインスイッチング素子と；前記トランスの第２の巻線
の巻始めと前記入力電源の前記他方の極との間に接続さ
れスイッチングにともなうリセット電流のON/OFFを行う
リセット電流導通用素子と；前記トランスの第３の巻線
の出力を入力し整流平滑した出力を外部に供給する整流
平滑回路と；前記整流平滑回路の出力に基づいて前記メ
インスイッチング素子のON/OFF制御を行う第１の制御信
号と前記リセット導通用素子のON/OFF制御を行う第２の
制御信号とを出力する安定化制御回路とを備え、前記メ
インスイッチング素子のON時間を、外部に供給する出力
電圧が所定の値になるようにスイッチング周期の1/2を
越えない範囲内で制御し、前記メインスイッチング素子
のON時間の後縁からそのON時間と同じ時間だけ前記リセ
ット電流導通用素子のON制御を行う構成である。A forward type DC-DC converter according to the present invention comprises: an input power source; first and second windings and a third winding wound the same number of times; A transformer whose winding ends are both connected to one pole of the input power source;
A main switching element connected between the end of the first winding of the transformer and the other pole of the input power supply for switching the input current; and the beginning of the winding of the second winding of the transformer and the input A reset current conducting element which is connected between the other pole of the power supply and turns on / off a reset current associated with switching; an output of the third winding of the transformer which is input and rectified and smoothed is output to the outside A rectifying / smoothing circuit to be supplied; a first control signal for performing ON / OFF control of the main switching element based on an output of the rectifying / smoothing circuit, and a second control signal for performing ON / OFF control of the reset conducting element. And a stabilization control circuit for outputting the ON time, the ON time of the main switching element is controlled within a range not exceeding 1/2 of the switching cycle so that the output voltage supplied to the outside becomes a predetermined value, Serial is a rim for the same time as the ON time from the configuration for performing ON control of the reset current conducting element after ON time of the main switching element.
次に、本発明について図面を参照して説明する。 Next, the present invention will be described with reference to the drawings.
第１図は本発明の一実施例の回路図である。トランス
１の巻線1aは、入力電源５の正極と巻始めが接続され、
巻終りはメインスイッチング素子７の電流入力端子に接
続される。巻線1bは、巻線1aと同回数巻かれ、巻終りが
巻線1aの巻始めに接続され、巻始めはリセット電流導通
用素子６の電流出力端子に接続される。リセット電流導
通用素子６の電流入力端子は入力電源５の負極とメイン
スイッチング素子７の電流出力端子と接続される。巻線
1cは巻始めと巻終りが各々整流平滑回路４の２つの入力
端子に接続される。整流平滑回路４の正負の出力は各々
正負の出力端子20,21と、安定化制御回路８とに入力さ
れる。安定化制御回路８からの第１の制御信号C1は、メ
インスイッチング素子７のON/OFF制御端子に入力され、
出力電圧が安定化されるようにメインスイッチング素子
のON時間をスイッチング周期の1/2を越えない範囲内で
制御する。第２の制御信号C2は、リセット電流導通用素
子６のON/OFF制御端子に入力され、メインスイッチング
素子７のON時間の後縁からON時間と同じ時間だけリセッ
ト電流導通用素子６をONさせ、その他の時間はOFFさせ
る。FIG. 1 is a circuit diagram of one embodiment of the present invention. The winding 1a of the transformer 1 is connected to the positive electrode of the input power supply 5 at the beginning of winding.
The end of winding is connected to the current input terminal of the main switching element 7. The winding 1b is wound the same number of times as the winding 1a, the end of the winding is connected to the beginning of the winding 1a, and the beginning of the winding is connected to the current output terminal of the reset current conducting element 6. The current input terminal of the reset current conducting element 6 is connected to the negative electrode of the input power supply 5 and the current output terminal of the main switching element 7. Winding
1c is connected to two input terminals of the rectifying / smoothing circuit 4 at the beginning and end of winding, respectively. The positive and negative outputs of the rectifying and smoothing circuit 4 are input to positive and negative output terminals 20 and 21 and a stabilization control circuit 8, respectively. The first control signal C1 from the stabilization control circuit 8 is input to the ON / OFF control terminal of the main switching element 7,
The ON time of the main switching element is controlled so as not to exceed 1/2 of the switching cycle so that the output voltage is stabilized. The second control signal C2 is input to the ON / OFF control terminal of the reset current conducting element 6, and turns on the reset current conducting element 6 for the same time as the ON time from the trailing edge of the ON time of the main switching element 7. And off at other times.
第３図に安定化制御回路８の制御信号波形の一例を示
す。FIG. 3 shows an example of a control signal waveform of the stabilization control circuit 8.
メインスイッチング素子７のON時間の後縁からON時間
と同じ時間だけリセット電流導通用素子６をONさせるこ
とによってリセット電流を流してやり、トランス１をリ
セットする。The reset current is passed by turning on the reset current conducting element 6 for the same time as the ON time from the trailing edge of the ON time of the main switching element 7, and the transformer 1 is reset.
以上説明したように本発明のフォワード型DC−DCコン
バータは、トランスのリセット用巻線の電流をON/OFFす
るリセット電流導通用素子を備え、トランスのスイッチ
ング用巻線に接続されたスイッチング素子のON時間の後
縁からON時間と同じ時間だけリセット電流導通用素子を
ONさせリセット用巻線にリセット電流を流すことによ
り、トランスのリセットを行い、トランスの磁気飽和を
防止できる効果がある。As described above, the forward-type DC-DC converter of the present invention includes the reset current conducting element for turning on / off the current of the reset winding of the transformer, and includes the switching element connected to the switching winding of the transformer. From the trailing edge of the ON time, the reset current conduction element is
The transformer is reset by turning it on and causing a reset current to flow through the reset winding, thereby providing an effect of preventing magnetic saturation of the transformer.
第１図は本発明の一実施例の回路図、第２図は従来のフ
ォワード型DC−DCコンバータの一例を示す回路図、第３
図は安定化制御回路の制御信号波形の一例を示す図であ
る。 １……トランス、1a,1b,1c……巻線、４……整流平滑回
路、５……入力電源、６……リセット電流導通用素子、
７……メインスイッチング素子、8,18……安定化制御回
路、16……ダイオード。FIG. 1 is a circuit diagram of one embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a conventional forward type DC-DC converter, FIG.
The figure shows an example of a control signal waveform of the stabilization control circuit. DESCRIPTION OF SYMBOLS 1 ... Transformer, 1a, 1b, 1c ... Winding, 4 ... Rectifying smoothing circuit, 5 ... Input power supply, 6 ... Reset current conduction element,
7: Main switching element, 8, 18: Stabilization control circuit, 16: Diode.
Claims (1)
２の巻線と第３の巻線とを有し第１の巻線の巻始めと第
２の巻線の巻終りがともに前記入力電源の一方の極に接
続されたトランスと；前記トランスの第１の巻線の巻終
りと前記入力電源の他方の極との間に接続され入力電流
のスイッチングを行うメインスイッチング素子と；前記
トランスの第２の巻線の巻始めと前記入力電源の前記他
方の極との間に接続されスイッチングにともなうリセッ
ト電流のON/OFFを行うリセット電流導通用素子と；前記
トランスの第３の巻線の出力を入力し整流平滑した出力
を外部に供給する整流平滑回路と；前記整流平滑回路の
出力に基づいて前記メインスイッチング素子のON/OFF制
御を行う第１の制御信号と前記リセット導通用素子のON
/OFF制御を行う第２の制御信号とを出力する安定化制御
回路とを備え、前記メインスイッチング素子のON時間
を、外部に供給する出力電圧が所定の値になるようにス
イッチング周期の1/2を越えない範囲内で制御し、前記
メインスイッチング素子のON時間の後縁からそのON時間
と同じ時間だけ前記リセット電流導通用素子のON制御を
行うことを特徴とするフォワード型DC−DCコンバータ。An input power source; first and second windings and a third winding wound the same number of times, wherein the first winding starts and the second winding ends. A transformer connected to one pole of the input power supply; a main switching element connected between an end of the first winding of the transformer and the other pole of the input power supply for switching an input current; A reset current conducting element that is connected between the beginning of winding of the second winding of the transformer and the other pole of the input power supply and that turns on / off a reset current associated with switching; A rectifying / smoothing circuit for receiving the output of the winding of the rectifying / smoothing circuit and supplying a rectified / smoothed output to the outside; a first control signal for performing ON / OFF control of the main switching element based on an output of the rectifying / smoothing circuit; ON of conduction element
And a stabilization control circuit that outputs a second control signal for performing / OFF control, wherein the ON time of the main switching element is set to 1 / of the switching period so that the output voltage supplied to the outside becomes a predetermined value. A forward type DC-DC converter, wherein the control is performed within a range not exceeding 2, and the ON control of the reset current conducting element is performed for the same time as the ON time from the trailing edge of the ON time of the main switching element. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19023390A JP2861312B2 (en) | 1990-07-18 | 1990-07-18 | Forward DC-DC converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19023390A JP2861312B2 (en) | 1990-07-18 | 1990-07-18 | Forward DC-DC converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0479763A JPH0479763A (en) | 1992-03-13 |
| JP2861312B2 true JP2861312B2 (en) | 1999-02-24 |
Family
ID=16254710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19023390A Expired - Lifetime JP2861312B2 (en) | 1990-07-18 | 1990-07-18 | Forward DC-DC converter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2861312B2 (en) |
-
1990
- 1990-07-18 JP JP19023390A patent/JP2861312B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0479763A (en) | 1992-03-13 |
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