Precharge system for a semiconductor memory device

Abstract

A method for precharging a bit line pair or data line pair in a semiconductor memory device includes generating a precharge pulse signal when a write enable line is deactivated at the beginning of a read cycle. The line pair is rapidly precharged by a pair of large transistors which turn on in response to the pulse signal. The pulse signal ends and turns of the transistors before a word line is enabled during the read cycle to prevent the large transistors from interfering with the bit sensing operation. A precharge circuit for precharging a bit line pair or data line pair in a semiconductor memory device includes a pulse generator having a delay circuit that determines the pulse width of a precharge pulse which is generated when a write enable line is deactivated. A write and precharge circuit includes two large transistors connected between a line pair and a power source that turn on and rapidly precharge the line pair during the precharge pulse. A third large transistor is connected between the lines of the line pair to equalize the voltages of the lines when the precharge pulse is generated.