[54] SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE HAVING SUBSTRATE POTENTIAL DETECTING CIRCUIT LESS DAMAGED BY STATIC CHARGE PROPAGATED THERETO THROUGH SHARED CONDUCTIVE LINE
[75] Inventor: Makoto Miyazawa, Kanagawa, Japan
[73] Assignee: NEC Corporation, Tokyo, Japan
[21] Appl. No.: 838,037
[22] Filed: Apr. 22, 1997
[30] Foreign Application Priority Data
Apr. 25, 1996 [JP] Japan 8-105249
[51] Int. CI. H02H 3/20
[52] U.S. CI 361/91; 327/535
[58] Field of Search 361/18, 56, 91,
361/111; 327/77, 80, 530, 534, 535, 537, 538, 542, 543, 545
[56] References Cited
U.S. PATENT DOCUMENTS
4,691,287 9/1987 Suzuki et al 364/490
4,733,285 3/1988 Ishioka et al 257/23.13
4,833,650 5/1989 Hirayama et al 365/225.7
4,951,254 8/1990 Ontrop et al 365/201
4,970,727 11/1990 Miyawaki et al 371/21.3
5,315,166 5/1994 Arimoto 327/535
5,379,174 1/1995 Kasamoto 361/56
5,659,550 8/1997 Mehrotra et al 371/21.4
FOREIGN PATENT DOCUMENTS
0 144 680 6/1985 European Pat. Off H01L 23/54
0 317 014 5/1989 European Pat. Off G11C 29/00
Primary Examiner—Ronald W. Leja
Attorney, Agent, or Firm—-Young & Thompson
[57] ABSTRACT
A semiconductor integrated circuit device communicates with an external device through signal terminals, and is powered through power terminals; protective circuits are respectively connected to the signal terminals for discharging static electric charge through a shared conductive line to the power terminal connected to a ground line, and a potential level ol the semiconductor substrate is propagated through the shared conductive line to a detecting circuit for reversely biasing the semiconductor substrate at intervals; and an interrupting circuit discriminates isolating state ol the power terminal from the ground line so as to cut off a current path between the shared conductive line and the detecting circuit.
4 Claims, 3 Drawing Sheets
