JPS6425773U

JPS6425773U -

Info

Publication number: JPS6425773U
Application number: JP12032587U
Authority: JP
Priority date: 1987-08-04
Filing date: 1987-08-04
Publication date: 1989-02-13

Description

[Brief explanation of the drawing]

第１図は本考案の一実施例の回路図、第２図は
、従来のハイ・インピーダンス状態検出回路のブ
ロツク図である。図において、１……３ステート出力回路、２，
８，１０……プルアツプ抵抗、３，１１……プル
ダウン抵抗、４……第１の論理回路、５……オー
プンコレクタバツフア回路、６……第２の論理回
路、７……インバータ回路、９……ＡＮＤ回路、
１２……基準電圧源、１３……スイツチ回路、１
４……積分器、１５……制御回路、１６……Ａ−
Ｄ変換器。 FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional high impedance state detection circuit. In the figure, 1...3 state output circuit, 2,
8, 10... Pull-up resistor, 3, 11... Pull-down resistor, 4... First logic circuit, 5... Open collector buffer circuit, 6... Second logic circuit, 7... Inverter circuit, 9 ...AND circuit,
12... Reference voltage source, 13... Switch circuit, 1
4...Integrator, 15...Control circuit, 16...A-
D converter.

Claims

[Scope of utility model registration request]

first and second resistors connected in series between a predetermined power source and ground, and a signal line to be detected in a high impedance state connected to an intermediate connection point thereof; and a potential at the intermediate connection point. , a first logic circuit that detects that the potential at the intermediate connection point is higher than the potential when a predetermined signal is not output to the signal line; A high-voltage device characterized by comprising: a second logic circuit that detects a potential lower than that in a non-output state; and an AND circuit that receives the outputs of the first and second logic circuits as inputs.・Impedance state detection circuit.