Patent ID: 6212107
Filing Date: 2001-04-03
Classification: G11C,H02M

Abstract:
A charge pump circuit for performing multiple-voltage rectification by a first clock, a second clock, and a third clock, and outputting a stepped-up voltage, comprising:a first step-up capacitor for receiving said first clock composed of a prescribed cycle;a second step-up capacitor for receiving said second clock that becomes high level during the interval that said first clock is low level;a third step-up capacitor for receiving said third clock that becomes high level during the interval that said first clock is high level;a first transistor that receives the output clock of said first step-up capacitor, that turns ON/OFF in accordance with the output clock of said third step-up capacitor, and that is provided for outputting said stepped-up voltage that is higher than an external power supply voltage supplied from outside;a second transistor that turns ON/OFF in accordance with the output clock of said second step-up capacitor and that is provided for biasing the output voltage of said first step-up capacitor by the external power supply voltage;a third transistor that turns ON/OFF in accordance with the output clock of said second step-up capacitor and that is provided for biasing the output voltage of said third step-up capacitor by the external power supply voltage; anda fourth transistor that turns ON/OFF in accordance with the output clock of said third step-up capacitor and that is provided for biasing the output voltage of said second step-up capacitor by the external power supply voltage;said charge pump circuit further including:a leak current suppressing circuit that outputs said third clock at amplitude of said stepped-up voltage during normal operation and outputs said third clock at amplitude of said external power supply voltage during a burn-in test.