HIGH-POTENTIAL DETECTION CIRCUIT

摘要

PURPOSE:To obtain a high-potential detection circuit which can limit a stress voltage which is applied between a gate and a source of a MOS transistor of an inverter circuit for shaping waveform when detecting a high-potential input by an input-stage circuit and can prevent deterioration and damage of a gate insulation film. CONSTITUTION:An enhancement-type PMOS transistor PI and an enhancement- type NMOS transistor N1 where the source and the back gate are short-circuited are connected in series between an input node and a grounding potential node and are provided with an input stage circuit 12 where the drain of the NMOS transistor N1 becomes an output node and a waveform-shaping circuit 13 which is connected to the next stage of the input-starve circuit. Furthermore, a depletion-type MOS transistor ND which is inserted in series with a path between the input node of the input stage circuit and that of the waveform-shaping circuit and whose gate is connected to a power supply potential node is provided.