INTERNAL STEP-UP POWER SUPPLY GENERATOR OF SEMICONDUCTOR MEMORY DEVICE

摘要

PROBLEM TO BE SOLVED: To stabilize the voltage step-up, eliminate an active oscillator and reduce a maximum current by a method wherein, when a step-up voltage VPP level is dropped by the leakage in an active cycle, a main pump is operated. SOLUTION: If a step-up voltage VPP level is lower than a target voltage level, a step-up voltage oscillation enable signal VPPOSCE is outputted by logic 'High' from a detector 15 to operate an oscillator 16. The oscillator 16 generates a pulse-shaped step-up driving signal VPPDRV and drives a main pump 17 to supply charge to a step-up voltage VPP terminal. At that time, a detector 18 generates a detection enable signal VPPDET in accordance with a master clock PR to generate the step-up voltage oscillation enable signal VPPOSCE for the driving of the main pump 17. Further, a step-up voltage control signal generator 21 combines a latching signal PNAK with the master clock PR to generate a signal PAKEF and a latching delay signal generator 20 adjusts the time to supply charge to the VPP terminal by a pulse width.