JPH0363099U

JPH0363099U -

Info

Publication number: JPH0363099U
Application number: JP12166489U
Authority: JP
Priority date: 1989-10-19
Filing date: 1989-10-19
Publication date: 1991-06-20
Anticipated expiration: 2004-10-19
Also published as: JP2581580Y2

Description

[Brief explanation of drawings]

第１図は本考案の一実施例による過電流時間監
視回路の回路図、第２図は第１図の過電流時間監
視回路における各部の信号の波形図、第３図はプ
ログラマブル・インターバル・タイマ回路のモー
ド説明図、第４図はプログラマブル・インターバ
ル・タイマ回路における過電流監視状態の説明図
、第５図は従来の定電流チヨツパ駆動回路の回路
図、そして第６図は第５図の回路における負荷に
流れる電流の波形図である。１……過電流時間監視回路、２……ピーク値ホ
ールド回路、２ａ……オペアンプ、３……コンパ
レータ回路、３ａ……コンパレータ、４……タイ
マ回路、４ａ……プログラマブル・インターバル
・タイマ回路（８２５３）、４ｂ……ＮＡＮＤ回
路（論理回路）、２１……ハイブリツドＩＣ、Ｌ
１，Ｌ３……負荷、ＲＳ……電流検出用抵抗器。 Figure 1 is a circuit diagram of an overcurrent time monitoring circuit according to an embodiment of the present invention, Figure 2 is a waveform diagram of signals at various parts in the overcurrent time monitoring circuit of Figure 1, and Figure 3 is a programmable interval timer. An explanatory diagram of the mode of the circuit, Fig. 4 is an explanatory diagram of the overcurrent monitoring state in the programmable interval timer circuit, Fig. 5 is a circuit diagram of a conventional constant current chopper drive circuit, and Fig. 6 is the circuit of Fig. 5. FIG. 3 is a waveform diagram of a current flowing through a load in FIG. DESCRIPTION OF SYMBOLS 1... Overcurrent time monitoring circuit, 2... Peak value hold circuit, 2a... Operational amplifier, 3... Comparator circuit, 3a... Comparator, 4... Timer circuit, 4a... Programmable interval timer circuit (8253 ), 4b...NAND circuit (logic circuit), 21...Hybrid IC, L
1, L3...Load, RS...Resistor for current detection.

Claims

[Scope of Claim for Utility Model Registration] An overcurrent time monitoring circuit for a dielectric load in a constant current chopper drive circuit in which control means temporarily causes an overcurrent exceeding the rating of the inductive load to flow through the inductive load. , a peak value hold circuit that smoothes the chopper voltage in the current detection resistor used to detect the current flowing through the inductive load, a comparator circuit that processes the output pulse from the peak value hold circuit at a predetermined slice level, and from the comparator circuit. a logic circuit that performs a logical operation between the output pulse of the logic circuit and a clock pulse given by an appropriate means, and the output pulse from the logic circuit is used as a trigger to count a preset number of counts based on a predetermined clock cycle; An overcurrent time monitoring circuit for an inductive load, which is equipped with a programmable interval timer circuit that outputs a predetermined signal when an overcurrent occurs.