Charge pump circuit for a semiconductor memory device

摘要

A charge pump circuit of a semiconductor memory device provides high efficiency. A high voltage detector outputs a high voltage detection signal. A regulator outputs a high level and a controller is triggered at a descent edge of a row access strobe bar signal and outputs a high level row access strobe bar pulse signal. An oscillator generates an oscillation pulse signal in accordance with the high level turn-on signal outputted from the regulator. A charge pump performs a pumping operation until the oscillation pulse signal reaches a potential of (Vdd+2Vt) when the oscillation pulse signal is applied thereto, and halts the pumping operation when the high level high voltage detection signal is applied. A pull-up transistor precharges the raised voltage Vpp to a potential of (Vdd-Vt) when power is turned on. The circuit enables a charge pump to have a double booster and a pumping capacitor, thereby satisfying a fast charge supply at a low level voltage and to supply an appropriate amount of charge at a high level voltage.