Patent ID: 6710634
Filing Date: 2004-03-23
Classification: H03K

Abstract:
A power on reset circuit incorporated in a semiconductor device and generating a reset signal for resetting said semiconductor device when power is turned on, comprising:an inverter driving said reset signal to an activated level in response to reception of a power supply potential and a reference potential, and driving said reset signal to an inactivated level in response to a potential of an input node of the inverter exceeding a predetermined threshold potential; a first resistance element having one electrode receiving said power supply potential and another electrode connected to the input node of said inverter; and a first transistor of a first conductivity type having a first electrode receiving said reference potential and a second electrode connected to the input node of said inverter, and rendered conductive in response to said reset signal attaining the activated level; wherein said first resistance element includes a second transistor of a second conductivity type having a first electrode receiving said power supply potential, a second electrode connected to the input node of said inverter and an input electrode receiving said reference potential; wherein said inverter includes a third transistor of the second conductivity type having a first electrode receiving said power supply potential, a second electrode connected to an output node of said inverter and an input electrode connected to the input node of said inverter, and a fourth transistor of the first conductivity type having a first electrode receiving said reference potential, a second electrode connected to said output node and an input electrode connected to said input node, said predetermined threshold potential being made approximately equal to a threshold potential of said fourth transistor; a seventh transistor of the first conductivity type having a first electrode and an input electrode both receiving said reference potential and a second electrode connected to the input node of said inverter; and an eighth transistor of the second conductivity type having a first electrode and an input electrode both receiving said power supply potential and a second electrode connected to the output node of said inverter.