JPS5895924A - Protecting circuit - Google Patents
Protecting circuitInfo
- Publication number
- JPS5895924A JPS5895924A JP19539981A JP19539981A JPS5895924A JP S5895924 A JPS5895924 A JP S5895924A JP 19539981 A JP19539981 A JP 19539981A JP 19539981 A JP19539981 A JP 19539981A JP S5895924 A JPS5895924 A JP S5895924A
- Authority
- JP
- Japan
- Prior art keywords
- load
- current
- down resistor
- circuit
- power supply
- 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.)
- Pending
Links
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
この発明は、保護回路に関し、特にたとえば直流電源に
接続された負荷が短絡することによって生じる過大電流
の防止を図るための保護回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protection circuit, and more particularly to a protection circuit for preventing excessive current caused by a short circuit in a load connected to a DC power source, for example.
従来、直流電源に負荷を接続する場合、たとえば負荷が
短絡しても過大電流が流れないように直流電源と負荷と
の間にヒユーズやブレーカなどの限流手段を設けたもの
があった。ところで、直流電源の出力電圧を所定の電圧
に降下させて負荷に与えるために、限流手段と負荷との
間に降圧抵抗を介挿する場合がある。このような場合、
直流電源と負荷との間に直列抵抗を有することになる。Conventionally, when a load is connected to a DC power source, a current limiting means such as a fuse or a breaker is provided between the DC power source and the load to prevent excessive current from flowing even if the load is short-circuited. Incidentally, in order to lower the output voltage of the DC power supply to a predetermined voltage and apply it to the load, a step-down resistor may be inserted between the current limiting means and the load. In such a case,
There will be a series resistance between the DC power source and the load.
そのため、たとえ負荷が短絡されても前記降圧抵抗で電
力が消費され限流手段が機能しないことがあった。この
ような状態で長時間放置されると、降圧抵抗が異常に発
熱し、火災の原因となったりまわりの１路へ悪影響を与
えたりする。Therefore, even if the load is short-circuited, power is consumed by the step-down resistor, and the current limiting means may not function. If left in this condition for a long time, the step-down resistor will generate abnormal heat, which may cause a fire or adversely affect the surrounding circuits.
それゆえに、この発明の主たる目的は、負荷に過大電流
が流れたとき確実にａ流手段を機能させ得る保護回路を
提供することである。Therefore, the main object of the present invention is to provide a protection circuit that can reliably function the a-flow means when an excessive current flows through the load.
この発明は、要約すれば、限流手段と降圧抵抗と負荷と
が直流電源に画列に接続されるような回路において、負
荷に過大電流が流れたとき降圧抵抗に流れる電流を側路
し限流手段によって直流電源の出力を確実に遮断させる
ための側路手段を降圧抵抗に並列的に接続するようにし
たものであるこの発明の上述の目的およびその他の目的
と特１！は、図面を参照して行なう以下の詳細な説明か
ら一層明らかとなろう。In summary, the present invention provides a circuit in which a current limiting means, a step-down resistor, and a load are connected in series to a DC power supply, and when an excessive current flows through the load, the current flowing through the step-down resistor is shunted and limited. The above-mentioned objects and other objects and features of the present invention are such that a bypass means for reliably cutting off the output of a DC power source by a current means is connected in parallel to a step-down resistor.1! will become clearer from the detailed description below with reference to the drawings.
図面はテレビジョン受＊＊に適用したこの発明の一実施
例を示す回路図である。構成において、直流電１１１の
出力電圧はヒユーズなどの限流素子２の一方端子に与え
られる。このヒユーズ２の他方端子は直流電源１の出力
電圧を所定の電圧まで降圧せさるための降圧１Ｎ３に接
続される。この降圧回路３はその一端がｌ流素子２の他
方端子に接続される降圧抵抗３１と、この降圧抵抗３１
の他端に接続されかつ接地される平滑コンデンサ３２と
を含む。この降圧回路３の出力は降圧抵抗３１と平滑コ
ンデンサ３２との接続点から得られ、その出力は負荷４
に与えられる。The drawing is a circuit diagram showing an embodiment of the present invention applied to a television receiver**. In the configuration, the output voltage of the DC current 111 is applied to one terminal of a current limiting element 2 such as a fuse. The other terminal of this fuse 2 is connected to a step-down voltage 1N3 for stepping down the output voltage of the DC power supply 1 to a predetermined voltage. This step-down circuit 3 includes a step-down resistor 31 whose one end is connected to the other terminal of the l-flow element 2, and this step-down resistor 31.
and a smoothing capacitor 32 connected to the other end and grounded. The output of the step-down circuit 3 is obtained from the connection point between the step-down resistor 31 and the smoothing capacitor 32, and the output is obtained from the load 4.
given to.
また、前記ｉ＊本子２の他方端子は低インピーダンスの
直流−直流コンバータ５に接続される。Further, the other terminal of the i* main unit 2 is connected to a low impedance DC-DC converter 5.
この直流−１ｉｒ流コンバータ５はフライバックトラン
ス５１と、水平ドライブ回路５２と、水平出力トランジ
スタ５３と、平滑回路を構成するダイオード５４および
コンデンサ５５とを含む。この直流−直流コンバータ５
において、直流電１ｌｉ１の出力はフライバックトラン
ス５１の１次コイル５１８に与えられるとともに、水平
ドライブ回路５２に駆動電圧として与えられる。また、
図面に示すフライバンクトランス５１の２次コイル５１
ｂは低電圧用の２次コイルである。This DC-1IR current converter 5 includes a flyback transformer 51, a horizontal drive circuit 52, a horizontal output transistor 53, and a diode 54 and a capacitor 55 forming a smoothing circuit. This DC-DC converter 5
In this case, the output of the DC current 1li1 is applied to the primary coil 518 of the flyback transformer 51, and is also applied to the horizontal drive circuit 52 as a driving voltage. Also,
Secondary coil 51 of flybank transformer 51 shown in the drawing
b is a secondary coil for low voltage.
上述のｉ！ｉ流−＊流コンバータ５の出力は負荷６に与
えられるとともに、ダイオード７を介して負ＩＩ＠４に
与えられる。なお、ダイオード７は直流−直流コンバー
タ５から負荷４へ向かう方向が順方向となるようにその
アノードが直流−直流コンバータ５側に接続され、その
カソードが負Ｍ４側に接続される。The above i! The output of the i-current-* current converter 5 is applied to a load 6 and also to a negative II@4 via a diode 7. Note that the diode 7 has its anode connected to the DC-DC converter 5 side and its cathode connected to the negative M4 side so that the direction from the DC-DC converter 5 to the load 4 is the forward direction.
ここで、負荷４に正常に電流が流れている場合、降圧回
路３の出力電圧ｖ２が直流−直流コンバータ５の出力電
圧■３よりも大きくなるように回路設定が行なわれる。Here, when current is normally flowing through the load 4, the circuit is set so that the output voltage v2 of the step-down circuit 3 is larger than the output voltage 3 of the DC-DC converter 5.
動作において、負荷４に正常に電流が流れている場合、
前述のようにＶ２＞Ｖ３となっているためダイオード７
は非導通となっている。そのため、負荷４には直流側１
から降圧抵抗３１を介して電流が与えられる。During operation, if current is flowing normally to load 4,
As mentioned above, since V2>V3, diode 7
is non-conducting. Therefore, load 4 has DC side 1
A current is applied from the voltage drop resistor 31 through the step-down resistor 31.
一方、たとえば負荷４が知略し、負荷４に過大電流が流
れた場合、降圧回路３ケ負荷４とダイオード７との接続
点８の電位も接地電位となる。したがって、ダイオード
７のカソード電位が７ノ一ド亀位よりも低くなり、ダイ
オード７が導通する。On the other hand, if, for example, the load 4 is unaware of this and an excessive current flows through the load 4, the potential at the connection point 8 between the three voltage step-down circuits, the load 4, and the diode 7 also becomes the ground potential. Therefore, the cathode potential of the diode 7 becomes lower than the 7th node voltage, and the diode 7 becomes conductive.
前述のように、直流−直流コンバータ５は低インピーダ
ンスであるため、負荷４には過大電流が流れ続ける。そ
のため、限流素子２が溶断され、直流側１の出りが遮断
される。As described above, since the DC-DC converter 5 has low impedance, an excessive current continues to flow through the load 4. Therefore, the current limiting element 2 is fused and the output of the DC side 1 is cut off.
以上のごとく、この実施例ではｆＡ葡４が知略されれば
、ｉ流電１１からの電流が直流−ｉｋ流コンバータ５お
よびダイオード７を介して負荷４に流れ込み、確実に限
流素子２を機能させる。したがって、降圧抵抗３１が異
常に発熱するのを防止することができる。As described above, in this embodiment, if the fA 4 is ignored, the current from the i current 11 flows into the load 4 via the DC-ik current converter 5 and the diode 7, ensuring that the current limiting element 2 functions properly. let Therefore, it is possible to prevent the step-down resistor 31 from generating abnormal heat.
なお、上述の説明ではテレビジョン受像機に適用した場
合を示したが、他の回路にも適用Ｃきることは勿論であ
る。In addition, although the above description shows the case where it is applied to a television receiver, it goes without saying that it can also be applied to other circuits.
以上のように、この発明によれば、負荷に過大電流が流
れたとき降圧抵抗に流れる電流を側路し限流手段によっ
て確実に直流電源の出力を遮断させるようにしたので、
負荷に過大電流が流れても確実に回路を保護することが
できる。As described above, according to the present invention, when an excessive current flows through the load, the current flowing through the step-down resistor is shunted and the output of the DC power supply is reliably cut off by the current limiting means.
The circuit can be reliably protected even if excessive current flows through the load.
図面はこの発明の一実施例を示す回路図である。
図において、１は直流電源、２は限流素子、３は降圧回
路、４は負荷、５は直流−直流コンバータ、７はダイオ
ード、３１は降圧抵抗を示す。The drawing is a circuit diagram showing an embodiment of the present invention. In the figure, 1 is a DC power supply, 2 is a current limiting element, 3 is a step-down circuit, 4 is a load, 5 is a DC-DC converter, 7 is a diode, and 31 is a step-down resistor.
Claims (2)
段、 前記限流手段と前記負荷との間に介挿される降圧抵抗、
および 前記降圧抵抗に並列的に接続され、かつ前記負荷に過大
電流が流れたとき前記降圧抵抗に流れる電流を側路し、
前記Ｉｉ流手段によって前記直流電源の出力を遮断する
ための側路手段を備える、保護回路。(1) a DC power supply, a load, a current limiting means interposed between the 111i1E power supply and the load, a step-down resistor interposed between the current limiting means and the load,
and is connected in parallel to the step-down resistor, and bypasses the current flowing to the step-down resistor when an excessive current flows through the load;
A protection circuit comprising bypass means for cutting off the output of the DC power supply by the Ii flow means.
圧抵抗の出力電圧よりも大きくなる回路手段と、 前記四路手段と前記負荷との圀に介挿されるダイオード
とを備える、特許請求の範囲第１項記載の保護回路。(2) The bypass means is inserted between the circuit means whose output voltage becomes larger than the output voltage of the step-down resistor when an excessive current flows through the load, and the four-way means and the load. The protection circuit according to claim 1, comprising a diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19539981A JPS5895924A (en) | 1981-12-03 | 1981-12-03 | Protecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19539981A JPS5895924A (en) | 1981-12-03 | 1981-12-03 | Protecting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5895924A true JPS5895924A (en) | 1983-06-07 |
Family
ID=16340478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19539981A Pending JPS5895924A (en) | 1981-12-03 | 1981-12-03 | Protecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5895924A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62132638U (en) * | 1986-02-14 | 1987-08-21 |
-
1981
- 1981-12-03 JP JP19539981A patent/JPS5895924A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62132638U (en) * | 1986-02-14 | 1987-08-21 |
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