HIGH EFFICIENCY CHARGE PUMP CIRCUIT FOR SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE: A high-efficiency charge pump circuit of a semiconductor memory device is provided to improve the efficiency of charge supply and to reduce of a power consumption by providing boosting voltage to an end load output terminal. CONSTITUTION: A pull-up transistor(25) pre-charges boosted voltage(Vpp) to VDD-Vt at initial power-up. A high-voltage detecting unit(22) generates a high level signal(HVDET) when source voltage(VDD) reaches to predetermined voltage after powering-up, thereby stopping the operation of a double booster circuit in a charge pump(25). A regulator(23) outputs an on-signal with a high-level when a level of voltage lower than the predetermined voltage is inputted, while monitoring the boosted voltage(Vpp). A controller(21) provides an RAS pulse of high-level to the charge pump(25) during a predetermined period, for the charge pump(25) to perform a pumping operation. An oscillator(24) an oscillated pulse signal(OSCH) with a constant period in response to the on-signal of high-level from the regulator(23). The charge pump(25) performs the pumping operation in response to the oscillated pulse signal(OSCH), until the boosted voltage reaches to VDD+2Vt.