JPH0477675A - Overcurrent protection circuit - Google Patents
Overcurrent protection circuitInfo
- Publication number
- JPH0477675A JPH0477675A JP19205290A JP19205290A JPH0477675A JP H0477675 A JPH0477675 A JP H0477675A JP 19205290 A JP19205290 A JP 19205290A JP 19205290 A JP19205290 A JP 19205290A JP H0477675 A JPH0477675 A JP H0477675A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- power supply
- overcurrent protection
- constant current
- current
- 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
Landscapes
- Measurement Of Current Or Voltage (AREA)
- Emergency Protection Circuit Devices (AREA)
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】
産業上の利用分野
本発明は、電源回路から負荷への電源供給時にその過電
流の保護を行なう過電流保護回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an overcurrent protection circuit that protects against overcurrent when power is supplied from a power supply circuit to a load.
従来の技術
従来、例えばテレビジョン受像機にはその水平偏向回路
への電源供給時に過電流の保護を行なう過電流保護回路
が設けられており、第２図に示す如く構成されていた。2. Description of the Related Art Conventionally, for example, a television receiver has been provided with an overcurrent protection circuit for protecting against overcurrent when power is supplied to its horizontal deflection circuit, and has a configuration as shown in FIG.
即ち、（１）は商用交流電源を整流平滑し直流電源とし
て出力する電源回路、（２）は電源回路（１）からの電
源供給を受けて作動し水平偏向コイルへの偏向電流の供
給とフライバンクトランスによる高電圧発生を行なわせ
る水平偏向回路、（３）はその電源供給線路（４）上に
設けられた電流検出用抵抗、（５）は電流検出用抵抗（
３）の両端にエミッタ・ベース間が接続されその電流検
出用抵抗（３）での電圧降下を増幅してコレクタ側より
出力する増幅用トランジスタ、（６）はそのバイアス抵
抗、（７）は増幅用トランジスタ（５）からの増幅出力
が電流制限用抵抗（８）を介して供給される制御回路で
、該制御回路（７）は増幅用トランジスタ（５）からの
増幅出力を受けて電源回路（１）の動作を停止させるよ
うになっている。In other words, (1) is a power supply circuit that rectifies and smoothes commercial AC power and outputs it as DC power, and (2) is operated by receiving power from power supply circuit (1) and supplies deflection current to the horizontal deflection coil and fly. A horizontal deflection circuit that generates high voltage by a bank transformer, (3) is a current detection resistor provided on its power supply line (4), and (5) is a current detection resistor (
3) is an amplification transistor whose emitter and base are connected to each other, and which amplifies the voltage drop across the current detection resistor (3) and outputs it from the collector side; (6) is its bias resistor; and (7) is the amplification transistor. This is a control circuit to which the amplified output from the amplifying transistor (5) is supplied via the current limiting resistor (8), and the control circuit (7) receives the amplified output from the amplifying transistor (5) and supplies it to the power supply circuit ( 1) is stopped.
ここで、正常な電源供給状態においては、電源供給線路
（４）に流れる電流によって生じる電流検出用抵抗（３
）での電圧降下が、増幅用トランジスタ（５）の非導通
領域であるように設定されているものとする。Here, in a normal power supply state, the current detection resistor (3) generated by the current flowing in the power supply line (4)
) is set so that it is a non-conducting region of the amplification transistor (5).
従って、異常な電源供給状態になった場合、例えば水平
偏向回路（２）側のフライバックトランスにレアショー
ト等の故障が生じてその電源供給線路（４）に流れる電
流が増大した場合には、電流検出用抵抗（３）での電圧
降下が大きくなるため、増幅用トランジスタ（５）が非
導通状態から導通（能動）状態となってそのコレクタ側
に電圧降下に応じた増幅出力を生じ、制御回路（７）は
その増幅出力を受けて電源回路（１）の動作を停止させ
るようになっている。Therefore, if an abnormal power supply condition occurs, for example, if a failure such as a layer short occurs in the flyback transformer on the horizontal deflection circuit (2) side and the current flowing through the power supply line (4) increases, As the voltage drop across the current detection resistor (3) increases, the amplification transistor (5) changes from a non-conducting state to a conducting (active) state, producing an amplified output on its collector side in accordance with the voltage drop, and controlling The circuit (7) receives the amplified output and stops the operation of the power supply circuit (1).
Ｂ ＜” しよ゛と る量
ところが、断る従来構成の過電流保護回路では、例えば
水平偏向回路（２）側のフライバックトランスに生じた
ショートの状態によっては、電源回路（１）の出力電圧
が低下して、増幅用トランジスタ（５）のエミッタ側電
位が低下してそのコレクタ側からの出力電流が低下する
場合があり、その際過大な増幅出力による過電流防止の
ための電流制限用抵抗（８）が介在しているため、増幅
用トランジスタ（５）のコレクタ側より制御回路（７）
に充分な電流を供給することが出来ず、制御回路（７）
の動作が不安定になると云った問題を生していた。However, in the conventional overcurrent protection circuit, the output voltage of the power supply circuit (1) may decrease depending on the short circuit that occurs in the flyback transformer on the horizontal deflection circuit (2) side. As a result, the potential on the emitter side of the amplification transistor (5) decreases, and the output current from its collector side may decrease. (8), the control circuit (7) is connected to the collector side of the amplification transistor (5).
It is not possible to supply sufficient current to the control circuit (7).
This caused problems such as unstable operation.
本発明はこのような点に鑑み成されたものであって、電
源回路の出力電圧が低下した場合においても、制御回路
を安定に動作させて、過電流保護を確実に行なわせるよ
うにした信頼性の高い過電流保護回路を提供することを
目的とする。The present invention has been made in view of the above points, and is a reliable system that allows the control circuit to operate stably and ensure overcurrent protection even when the output voltage of the power supply circuit decreases. The purpose of this invention is to provide a highly reliable overcurrent protection circuit.
課 を”°するための“
上記した目的を達成するため本発明では、電源回路から
負荷への電源供給時に過電流の保護を行なう過電流保護
回路において、電源供給線路上に設けられた電流検出用
抵抗と、該電流検出用抵抗の電圧降下を増幅して出力す
る増幅回路と、該増幅回路からの増幅出力を受けて定電
流出力を行なう定電流回路と、該定電流回路からの定電
流出力を受けて電源回路の動作制御を行なう制御回路と
より構成したものである。In order to achieve the above object, the present invention provides an overcurrent protection circuit that protects against overcurrent when power is supplied from a power supply circuit to a load. an amplifier circuit that amplifies and outputs the voltage drop of the current detection resistor, a constant current circuit that receives the amplified output from the amplifier circuit and outputs a constant current, and a constant current output from the constant current circuit. It consists of a control circuit that receives the output and controls the operation of the power supply circuit.
作−■
このような構成によると、定電流回路により、制御回路
には常に一定した充分な電流が供給され、制御回路の安
定した動作が得られることになる。According to this configuration, a constant and sufficient current is always supplied to the control circuit by the constant current circuit, and stable operation of the control circuit can be obtained.
叉」Ｌ貫 以下、本発明の一実施例について図面と共に説明する。”L” An embodiment of the present invention will be described below with reference to the drawings.
尚、従来と同一部分については同一符号を付すと共にそ
の説明を省略する。It should be noted that the same parts as those in the prior art will be given the same reference numerals and the explanation thereof will be omitted.
本実施例では第１図の電流制限用抵抗（８）に替えて、
第２図に示すように増幅用トランジスタ（５）のコレク
タと制御回路（７）の間に定電流回路（９）を設けたも
ので、該定電流回路（９）は定電流用トランジスタ（１
０）と、そのバイアス抵抗（１１）。In this embodiment, instead of the current limiting resistor (8) in Fig. 1,
As shown in Fig. 2, a constant current circuit (9) is provided between the collector of the amplifying transistor (5) and the control circuit (7), and the constant current circuit (9) is connected to the constant current transistor (1).
0) and its bias resistance (11).
バイアス用ダイオード（１２） 、帰還抵抗（１３）と
で構成されており、増幅用トランジスタ（５）の出力を
受けてその出力の大小に拘らず制御回路（７）に定電流
出力を行なうようになっている。It is composed of a bias diode (12) and a feedback resistor (13), and receives the output of the amplification transistor (5) and outputs a constant current to the control circuit (7) regardless of the magnitude of the output. It has become.
従って、水平偏向回路（２）側のフライバックトランス
のショート等により電源供給線路（４）に過電流が流れ
て、例えば電源回路（１）の出力電圧が低下した場合に
おいても、即ち増幅用トランジスタ（５）のエミッタ側
電位が低下してそのコレクタ側からの出力電流が低下し
ても、定電流回路（９）を通じて、制御回路（７）に一
定した充分な駆動用の電流を供給することが出来るので
、安定した制御回路の動作が得られ、過電流保護を確実
に行なわせることが出来る。Therefore, even if an overcurrent flows in the power supply line (4) due to a short circuit in the flyback transformer on the horizontal deflection circuit (2) side, and the output voltage of the power supply circuit (1) decreases, for example, the amplification transistor Even if the emitter side potential of (5) decreases and the output current from its collector side decreases, a constant and sufficient driving current is supplied to the control circuit (7) through the constant current circuit (9). Therefore, stable operation of the control circuit can be obtained, and overcurrent protection can be performed reliably.
光凱勿燕来
上述した如く本発明の過電流保護回路に依れば、過電流
が生じた際にその電源回路の電源電圧が低下しても、定
電流回路を通じて制御回路に常に一定した充分な電流を
供給することが出来るので、過電流保護を確実に行なわ
せることが出来る。As described above, according to the overcurrent protection circuit of the present invention, even if the power supply voltage of the power supply circuit decreases when an overcurrent occurs, the control circuit always receives a constant sufficient voltage through the constant current circuit. Since the current can be supplied, overcurrent protection can be performed reliably.
第１図は本発明の一実施例を示す回路図、第２図は従来
例を示す回路図である。
（１）−・電源回路、 （３） −電流検出用抵抗。
（４） −増幅用トランジスタ、 （７） −制御回路
。
（９） 一定電流回路。FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional example. (1) - Power supply circuit, (3) - Current detection resistor. (4) -Amplification transistor, (7) -Control circuit. (9) Constant current circuit.
Claims (1)
を行なう過電流保護回路において、電源供給線路上に設
けられた電流検出用抵抗と、該電流検出用抵抗の電圧降
下を増幅して出力する増幅回路と、該増幅回路からの増
幅出力を受けて定電流出力を行なう定電流回路と、該定
電流回路からの定電流出力を受けて電源回路の動作制御
を行なう制御回路とより成ることを特徴とする過電流保
護回路。(1) In an overcurrent protection circuit that protects against overcurrent when power is supplied from the power supply circuit to the load, a current detection resistor provided on the power supply line and the voltage drop across the current detection resistor are amplified. Consisting of an output amplifier circuit, a constant current circuit that receives the amplified output from the amplifier circuit and outputs a constant current, and a control circuit that receives the constant current output from the constant current circuit and controls the operation of the power supply circuit. An overcurrent protection circuit characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19205290A JPH0477675A (en) | 1990-07-20 | 1990-07-20 | Overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19205290A JPH0477675A (en) | 1990-07-20 | 1990-07-20 | Overcurrent protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0477675A true JPH0477675A (en) | 1992-03-11 |
Family
ID=16284819
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19205290A Pending JPH0477675A (en) | 1990-07-20 | 1990-07-20 | Overcurrent protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0477675A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009048434A1 (en) | 2008-10-15 | 2010-04-22 | Nec Tokin Corp., Sendai | Conductive polymer composition, process for its preparation and solid electrolytic capacitor |
| US9854670B2 (en) | 2013-08-22 | 2017-12-26 | Showa Denko K.K. | Transparent electrode and method for producing same |
-
1990
- 1990-07-20 JP JP19205290A patent/JPH0477675A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009048434A1 (en) | 2008-10-15 | 2010-04-22 | Nec Tokin Corp., Sendai | Conductive polymer composition, process for its preparation and solid electrolytic capacitor |
| US9854670B2 (en) | 2013-08-22 | 2017-12-26 | Showa Denko K.K. | Transparent electrode and method for producing same |
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