JPS63156579U

JPS63156579U -

Info

Publication number: JPS63156579U
Application number: JP4953287U
Authority: JP
Priority date: 1987-03-31
Filing date: 1987-03-31
Publication date: 1988-10-13

Description

[Brief explanation of the drawing]

第１図はこの考案の実施例である短絡保護回路
の要部の回路を示す図である。第２図は同短絡保
護回路の動作を説明するための図、第３図は従来
の短絡保護回路を含むスイツチングレギユレータ
の欠点を説明するための図、第４図は従来の短絡
保護回路を含むスイツチングレギユレータの概略
ブロツク図である。Ｑ…電源出力端子、Ｌ…負荷、Ｑ１…出力トラ
ンジスタ、Ｃ…制御回路、Ｄ…短絡保護回路、Ｄ
１…コンパレータ（短絡検出用比較手段）、Ｄ２
…短絡保護用タイマ回路、Ｑ３…トランジスタ（
スイツチ回路）、Ｄ４…誤動作防止用タイマ回路
。 FIG. 1 is a diagram showing a main part of a short-circuit protection circuit according to an embodiment of this invention. Figure 2 is a diagram to explain the operation of the short-circuit protection circuit, Figure 3 is a diagram to explain the drawbacks of a switching regulator that includes a conventional short-circuit protection circuit, and Figure 4 is a diagram to explain the short-circuit protection circuit. 1 is a schematic block diagram of a switching regulator including circuitry; FIG. Q...Power output terminal, L...Load, Q1...Output transistor, C...Control circuit, D...Short circuit protection circuit, D
1...Comparator (comparison means for short circuit detection), D2
...Timer circuit for short circuit protection, Q3...transistor (
switch circuit), D4...Timer circuit for preventing malfunction.

Claims

[Claims for Utility Model Registration] Comprising a control circuit that compares a power supply output with a reference value and controls the on-time of an output transistor based on the comparison output, and further sets the power supply output or the comparison output to another reference value. a short-circuit detection comparison means for determining whether or not the power supply output is in a short-circuit condition; a short-circuit protection timer circuit comprising a CR time constant circuit for timing the short-circuit condition detection time; A switching regulator comprising a short-circuit protection circuit including means for setting the output transistor to a substantially OFF state when time is measured, the short-circuit protection circuit including a switch circuit connected in parallel to the capacitor of the CR time constant circuit; A short-circuit protection circuit for a switching regulator, characterized in that it is provided with a timer circuit for preventing malfunction, which sets the switch circuit in an ON state for a certain period of time after the power is turned on.