SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

摘要

PROBLEM TO BE SOLVED: To enhance the efficiency of a step-up voltage generation circuit by isolating a second well region formed on a first well region through a third well region and forming an MOSFET for transmitting a step-up voltage to a capacitor on the output side in the second well region thus isolated. SOLUTION: A step-up voltage circuit transmits a step-up voltage to a capacitor on the output side through an MOSFET M1. A second D well region is formed on a first p well region which is isolated through a third n well region and the MOSFET M1 is formed in the second well region pWELL thus isolated. According to the structure, level loss can be reduced by supplying a step-up voltage to the second well region pWELL corresponding to the back gate of the MOSFET M1 thereby preventing the threshold voltage from increasing due to substrate effect.